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Sample records for graded visual perception

  1. Visual Arts Teaching in Kindergarten through 3rd-Grade Classrooms in the UAE: Teacher Profiles, Perceptions, and Practices

    Science.gov (United States)

    Buldu, Mehmet; Shaban, Mohamed S.

    2010-01-01

    This study portrayed a picture of kindergarten through 3rd-grade teachers who teach visual arts, their perceptions of the value of visual arts, their visual arts teaching practices, visual arts experiences provided to young learners in school, and major factors and/or influences that affect their teaching of visual arts. The sample for this study…

  2. Relationships between Fine-Motor, Visual-Motor, and Visual Perception Scores and Handwriting Legibility and Speed

    Science.gov (United States)

    Klein, Sheryl; Guiltner, Val; Sollereder, Patti; Cui, Ying

    2011-01-01

    Occupational therapists assess fine motor, visual motor, visual perception, and visual skill development, but knowledge of the relationships between scores on sensorimotor performance measures and handwriting legibility and speed is limited. Ninety-nine students in grades three to six with learning and/or behavior problems completed the Upper-Limb…

  3. Training Grade R teachers to impart visual perceptual skills for early reading

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    Christelle Andrich

    2015-08-01

    Full Text Available Visual Perception is the mind’s ability to interpret or give meaning to what is seen with the eyes (WCED 2006. Grade Reception Phase (R teachers, of five and six year-old learners, need to impart Visual Perceptual Skills (VPS during visual training for pre-reading. These prereading activities in Grade R support early reading progress in Grade 1, which is critical for improving basic literacy and numeracy education in South Africa. A quality Grade R programme which can deliver these visual training outcomes depends on a progressive model for effective pre- and in-service professional development of teachers. A model implemented via academic-governmental collaboration. This article seeks to describe and recommend best practices of such professional development. The recommendations are based on an overview of the current Grade R professional development landscape, a brief exposition of the Subject Content Knowledge (SCK of VPS, a document analysis of the Curriculum and Assessment Policy Statement (CAPS curriculum and, finally, a case study with a discourse analysis involving four Grade R teachers.

  4. Early Local Activity in Temporal Areas Reflects Graded Content of Visual Perception

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    Chiara Francesca Tagliabue

    2016-04-01

    Full Text Available In visual cognitive neuroscience the debate on consciousness is focused on two major topics: the search for the neural correlates of the different properties of visual awareness and the controversy on the graded versus dichotomous nature of visual conscious experience. The aim of this study is to search for the possible neural correlates of different grades of visual awareness investigating the Event Related Potentials (ERPs to reduced contrast visual stimuli whose perceptual clarity was rated on the four-point Perceptual Awareness Scale (PAS. Results revealed a left centro-parietal negative deflection (Visual Awareness Negativity; VAN peaking at 280-320 ms from stimulus onset, related to the perceptual content of the stimulus, followed by a bilateral positive deflection (Late Positivity; LP peaking at 510-550 ms over almost all electrodes, reflecting post-perceptual processes performed on such content. Interestingly, the amplitude of both deflections gradually increased as a function of visual awareness. Moreover, the intracranial generators of the phenomenal content (VAN were found to be located in the left temporal lobe. The present data thus seem to suggest 1 that visual conscious experience is characterized by a gradual increase of perceived clarity at both behavioral and neural level and 2 that the actual content of perceptual experiences emerges from early local activation in temporal areas, without the need of later widespread frontal engagement.

  5. Exploring the Link between Visual Perception, Visual-Motor Integration, and Reading in Normal Developing and Impaired Children using DTVP-2.

    Science.gov (United States)

    Bellocchi, Stéphanie; Muneaux, Mathilde; Huau, Andréa; Lévêque, Yohana; Jover, Marianne; Ducrot, Stéphanie

    2017-08-01

    Reading is known to be primarily a linguistic task. However, to successfully decode written words, children also need to develop good visual-perception skills. Furthermore, motor skills are implicated in letter recognition and reading acquisition. Three studies have been designed to determine the link between reading, visual perception, and visual-motor integration using the Developmental Test of Visual Perception version 2 (DTVP-2). Study 1 tests how visual perception and visual-motor integration in kindergarten predict reading outcomes in Grade 1, in typical developing children. Study 2 is aimed at finding out if these skills can be seen as clinical markers in dyslexic children (DD). Study 3 determines if visual-motor integration and motor-reduced visual perception can distinguish DD children according to whether they exhibit or not developmental coordination disorder (DCD). Results showed that phonological awareness and visual-motor integration predicted reading outcomes one year later. DTVP-2 demonstrated similarities and differences in visual-motor integration and motor-reduced visual perception between children with DD, DCD, and both of these deficits. DTVP-2 is a suitable tool to investigate links between visual perception, visual-motor integration and reading, and to differentiate cognitive profiles of children with developmental disabilities (i.e. DD, DCD, and comorbid children). Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  6. Motor-independent Visual Perception Skill Indexes are Related with Reading Skills in Children with Cerebral Palsy

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    Vahid Reza Khodabandeh

    2015-10-01

    Full Text Available Objective: Cerebral palsy is one of the most common causes of physical disability in childhood that lead to various difficulties for children. These children may have abnormalities in visual perception. Visual perception plays an important role in learning of basic childhood’s skills. This research was designed to study the relation between each of subtests of visual perception with accuracy and speed components of reading skills in school-aged cerebral palsy children. Materials & Methods: In this cross-sectional study, 24 spastic cerebral palsy students in second grade (10 girls and 14 boy were selected be available as from Tehran’s rehabilitation clinics. Visual perception and Reading skills were evaluated with the Test of Visual Perceptual Skill-revised (TVPS-R and Diagnostic Reading Test. Results: The results showed that between standard score of visual perception with accuracy and speed components of reading skills of cerebral palsy student were significantly correlated. Visual Discrimination with accuracy (P<0.001 and with speed (P<0.001, Visual Memory with accuracy  (P=0.002 and with speed (P=0.004, Visual-Spatial with accuracy (P<0.001 and with speed (P<0.001, Form Constancy with accuracy (P=0.003 and with speed (p<0.001, Visual Sequential Memory with accuracy (P=0.023 and with speed (P<0.028, Figure Ground Discrimination with accuracy (P=0.010 and with speed (P<0.011, Visual Closure with accuracy (p=0.009 and with speed (P<0.009 Conclusion: In general we can say that the relationship between visual perception skills with reading skills in first and second grade students with cerebral palsy is evident.

  7. Visual art and visual perception

    NARCIS (Netherlands)

    Koenderink, Jan J.

    2015-01-01

    Visual art and visual perceptionVisual art’ has become a minor cul-de-sac orthogonal to THE ART of the museum directors and billionaire collectors. THE ART is conceptual, instead of visual. Among its cherished items are the tins of artist’s shit (Piero Manzoni, 1961, Merda d’Artista) “worth their

  8. Music Alters Visual Perception

    NARCIS (Netherlands)

    Jolij, Jacob; Meurs, Maaike

    2011-01-01

    Background: Visual perception is not a passive process: in order to efficiently process visual input, the brain actively uses previous knowledge (e. g., memory) and expectations about what the world should look like. However, perception is not only influenced by previous knowledge. Especially the

  9. Perceptions of restaurateurs on quality grading

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    Joseph Roberson

    2014-01-01

    Full Text Available A restaurateur's strategic focus is to maximise wealth for the owner(s. To achieve wealth maximisation, a restaurateur could implement one or more of the following strategies: focus strategy, cost-leadership strategy and/or differentiation strategy. A management intervention a restaurateur could implement to achieve this is quality differentiation. Grading of an establishment will assist a restaurateur in becoming a market leader. Currently there no national restaurant grading system exists in South Africa. As support and participation of restaurateurs in any future quality grading system are essential, it is imperative to test their perceptions of the implementation of a quality grading scale. The aim of this paper is to gather the perceptions of restaurateurs of an envisaged scale that could be used to grade independent full-service restaurants. In this study the researcher tested the perceptions of restaurateurs using nine possible outcomes of implementing quality grading in the independent fullservice restaurant segment. The outcomes to be tested were presented to restaurateurs in a questionnaire uploaded on "survey monkey". This was emailed to 3 286 restaurateurs and 265 responses were received. Respondents who were positive regarding grading indicated that they were enthusiastic about the impact grading would have on international tourism, as well as the fact that it could contribute to an increase in the value of their establishments.

  10. Visual motion perception predicts driving hazard perception ability.

    Science.gov (United States)

    Lacherez, Philippe; Au, Sandra; Wood, Joanne M

    2014-02-01

    To examine the basis of previous findings of an association between indices of driving safety and visual motion sensitivity and to examine whether this association could be explained by low-level changes in visual function. A total of 36 visually normal participants (aged 19-80 years) completed a battery of standard vision tests including visual acuity, contrast sensitivity and automated visual fields and two tests of motion perception including sensitivity for movement of a drifting Gabor stimulus and sensitivity for displacement in a random dot kinematogram (Dmin ). Participants also completed a hazard perception test (HPT), which measured participants' response times to hazards embedded in video recordings of real-world driving, which has been shown to be linked to crash risk. Dmin for the random dot stimulus ranged from -0.88 to -0.12 log minutes of arc, and the minimum drift rate for the Gabor stimulus ranged from 0.01 to 0.35 cycles per second. Both measures of motion sensitivity significantly predicted response times on the HPT. In addition, while the relationship involving the HPT and motion sensitivity for the random dot kinematogram was partially explained by the other visual function measures, the relationship with sensitivity for detection of the drifting Gabor stimulus remained significant even after controlling for these variables. These findings suggest that motion perception plays an important role in the visual perception of driving-relevant hazards independent of other areas of visual function and should be further explored as a predictive test of driving safety. Future research should explore the causes of reduced motion perception to develop better interventions to improve road safety. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

  11. Towards computer-based perception by modeling visual perception : A probalistic theory

    NARCIS (Netherlands)

    Ciftcioglu, O.; Bittermann, M.; Sariyildiz, S.

    2006-01-01

    Studies on computer-based perception by vision modelling are described. The visual perception is mathematically modelled where the model receives and interprets visual data from the environment. The perception is defined in probabilistic terms so that it is in the same way quantified. Human visual

  12. Music alters visual perception.

    Directory of Open Access Journals (Sweden)

    Jacob Jolij

    Full Text Available BACKGROUND: Visual perception is not a passive process: in order to efficiently process visual input, the brain actively uses previous knowledge (e.g., memory and expectations about what the world should look like. However, perception is not only influenced by previous knowledge. Especially the perception of emotional stimuli is influenced by the emotional state of the observer. In other words, how we perceive the world does not only depend on what we know of the world, but also by how we feel. In this study, we further investigated the relation between mood and perception. METHODS AND FINDINGS: We let observers do a difficult stimulus detection task, in which they had to detect schematic happy and sad faces embedded in noise. Mood was manipulated by means of music. We found that observers were more accurate in detecting faces congruent with their mood, corroborating earlier research. However, in trials in which no actual face was presented, observers made a significant number of false alarms. The content of these false alarms, or illusory percepts, was strongly influenced by the observers' mood. CONCLUSIONS: As illusory percepts are believed to reflect the content of internal representations that are employed by the brain during top-down processing of visual input, we conclude that top-down modulation of visual processing is not purely predictive in nature: mood, in this case manipulated by music, may also directly alter the way we perceive the world.

  13. Perception of biological motion in visual agnosia

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    Elisabeth eHuberle

    2012-08-01

    Full Text Available Over the past twenty-five years, visual processing has been discussed in the context of the dual stream hypothesis consisting of a ventral (‘what' and a dorsal ('where' visual information processing pathway. Patients with brain damage of the ventral pathway typically present with signs of visual agnosia, the inability to identify and discriminate objects by visual exploration, but show normal perception of motion perception. A dissociation between the perception of biological motion and non-biological motion has been suggested: Perception of biological motion might be impaired when 'non-biological' motion perception is intact and vice versa. The impact of object recognition on the perception of biological motion remains unclear. We thus investigated this question in a patient with severe visual agnosia, who showed normal perception of non-biological motion. The data suggested that the patient's perception of biological motion remained largely intact. However, when tested with objects constructed of coherently moving dots (‘Shape-from-Motion’, recognition was severely impaired. The results are discussed in the context of possible mechanisms of biological motion perception.

  14. Visual memory and visual perception: when memory improves visual search.

    Science.gov (United States)

    Riou, Benoit; Lesourd, Mathieu; Brunel, Lionel; Versace, Rémy

    2011-08-01

    This study examined the relationship between memory and perception in order to identify the influence of a memory dimension in perceptual processing. Our aim was to determine whether the variation of typical size between items (i.e., the size in real life) affects visual search. In two experiments, the congruency between typical size difference and perceptual size difference was manipulated in a visual search task. We observed that congruency between the typical and perceptual size differences decreased reaction times in the visual search (Exp. 1), and noncongruency between these two differences increased reaction times in the visual search (Exp. 2). We argue that these results highlight that memory and perception share some resources and reveal the intervention of typical size difference on the computation of the perceptual size difference.

  15. The perception of visual emotion: comparing different measures of awareness.

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    Szczepanowski, Remigiusz; Traczyk, Jakub; Wierzchoń, Michał; Cleeremans, Axel

    2013-03-01

    Here, we explore the sensitivity of different awareness scales in revealing conscious reports on visual emotion perception. Participants were exposed to a backward masking task involving fearful faces and asked to rate their conscious awareness in perceiving emotion in facial expression using three different subjective measures: confidence ratings (CRs), with the conventional taxonomy of certainty, the perceptual awareness scale (PAS), through which participants categorize "raw" visual experience, and post-decision wagering (PDW), which involves economic categorization. Our results show that the CR measure was the most exhaustive and the most graded. In contrast, the PAS and PDW measures suggested instead that consciousness of emotional stimuli is dichotomous. Possible explanations of the inconsistency were discussed. Finally, our results also indicate that PDW biases awareness ratings by enhancing first-order accuracy of emotion perception. This effect was possibly a result of higher motivation induced by monetary incentives. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Visual perception skills testing: preliminary results

    CSIR Research Space (South Africa)

    Smith, Andrew C

    2009-02-01

    Full Text Available Good visual perception skills are important in the effective manipulation of Tangible User Interfaces. This paper reports on the application of a test set researchers have developed specifically to quantify the visual perception skills of children...

  17. Development of an automatic visual grading system for grafting seedlings

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    Subo Tian

    2017-01-01

    Full Text Available In this study, a visual grading system of vegetable grafting machine was developed. The study described key technology of visual grading system of vegetable grafting machine. First, the contrasting experiment was conducted between acquired images under blue background light and natural light conditions, with the blue background light chosen as lighting source. The Visual C++ platform with open-source computer vision library (Open CV was used for the image processing. Subsequently, maximum frequency of total number of 0-valued pixels was predicted and used to extract the measurements of scion and rootstock stem diameters. Finally, the developed integrated visual grading system was experimented with 100 scions and rootstock seedlings. The results showed that success rate of grading reached up to 98%. This shows that selection and grading of scion and rootstock could be fully automated with this developed visual grading system. Hence, this technology would be greatly helpful for improving the grading accuracy and efficiency.

  18. Neurocomputational account of memory and perception: Thresholded and graded signals in the hippocampus.

    Science.gov (United States)

    Elfman, Kane W; Aly, Mariam; Yonelinas, Andrew P

    2014-12-01

    Recent evidence suggests that the hippocampus, a region critical for long-term memory, also supports certain forms of high-level visual perception. A seemingly paradoxical finding is that, unlike the thresholded hippocampal signals associated with memory, the hippocampus produces graded, strength-based signals in perception. This article tests a neurocomputational model of the hippocampus, based on the complementary learning systems framework, to determine if the same model can account for both memory and perception, and whether it produces the appropriate thresholded and strength-based signals in these two types of tasks. The simulations showed that the hippocampus, and most prominently the CA1 subfield, produced graded signals when required to discriminate between highly similar stimuli in a perception task, but generated thresholded patterns of activity in recognition memory. A threshold was observed in recognition memory because pattern completion occurred for only some trials and completely failed to occur for others; conversely, in perception, pattern completion always occurred because of the high degree of item similarity. These results offer a neurocomputational account of the distinct hippocampal signals associated with perception and memory, and are broadly consistent with proposals that CA1 functions as a comparator of expected versus perceived events. We conclude that the hippocampal computations required for high-level perceptual discrimination are congruous with current neurocomputational models that account for recognition memory, and fit neatly into a broader description of the role of the hippocampus for the processing of complex relational information. © 2014 Wiley Periodicals, Inc.

  19. Neuroimaging of person perception: A social-visual interface.

    Science.gov (United States)

    Brooks, Jeffrey A; Freeman, Jonathan B

    2017-12-21

    The visual system is able to extract an enormous amount of socially relevant information from the face, including social categories, personality traits, and emotion. While facial features may be directly tied to certain perceptions, emerging research suggests that top-down social cognitive factors (e.g., stereotypes, social-conceptual knowledge, prejudice) considerably influence and shape the perceptual process. The rapid integration of higher-order social cognitive processes into visual perception can give rise to systematic biases in face perception and may potentially act as a mediating factor for intergroup behavioral and evaluative biases. Drawing on neuroimaging evidence, we review the ways that top-down social cognitive factors shape visual perception of facial features. This emerging work in social and affective neuroscience builds upon work on predictive coding and perceptual priors in cognitive neuroscience and visual cognition, suggesting domain-general mechanisms that underlie a social-visual interface through which social cognition affects visual perception. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Crossmodal influences on visual perception

    Science.gov (United States)

    Shams, Ladan; Kim, Robyn

    2010-09-01

    Vision is generally considered the dominant sensory modality; self-contained and independent of other senses. In this article, we will present recent results that contradict this view, and show that visual perception can be strongly altered by sound and touch, and such alterations can occur even at early stages of processing, as early as primary visual cortex. We will first review the behavioral evidence demonstrating modulation of visual perception by other modalities. As extreme examples of such modulations, we will describe two visual illusions induced by sound, and a visual illusion induced by touch. Next, we will discuss studies demonstrating modulation of activity in visual areas by stimulation of other modalities, and discuss possible pathways that could underpin such interactions. This will be followed by a discussion of how crossmodal interactions can affect visual learning and adaptation. We will review several studies showing crossmodal effects on visual learning. We will conclude with a discussion of computational principles governing these crossmodal interactions, and review several recent studies that demonstrate that these interactions are statistically optimal.

  1. Cortical visual prostheses: from microstimulation to functional percept

    Science.gov (United States)

    Najarpour Foroushani, Armin; Pack, Christopher C.; Sawan, Mohamad

    2018-04-01

    Cortical visual prostheses are intended to restore vision by targeted electrical stimulation of the visual cortex. The perception of spots of light, called phosphenes, resulting from microstimulation of the visual pathway, suggests the possibility of creating meaningful percept made of phosphenes. However, to date electrical stimulation of V1 has still not resulted in perception of phosphenated images that goes beyond punctate spots of light. In this review, we summarize the clinical and experimental progress that has been made in generating phosphenes and modulating their associated perceptual characteristics in human and macaque primary visual cortex (V1). We focus specifically on the effects of different microstimulation parameters on perception and we analyse key challenges facing the generation of meaningful artificial percepts. Finally, we propose solutions to these challenges based on the application of supervised learning of population codes for spatial stimulation of visual cortex.

  2. The role of human ventral visual cortex in motion perception

    Science.gov (United States)

    Saygin, Ayse P.; Lorenzi, Lauren J.; Egan, Ryan; Rees, Geraint; Behrmann, Marlene

    2013-01-01

    Visual motion perception is fundamental to many aspects of visual perception. Visual motion perception has long been associated with the dorsal (parietal) pathway and the involvement of the ventral ‘form’ (temporal) visual pathway has not been considered critical for normal motion perception. Here, we evaluated this view by examining whether circumscribed damage to ventral visual cortex impaired motion perception. The perception of motion in basic, non-form tasks (motion coherence and motion detection) and complex structure-from-motion, for a wide range of motion speeds, all centrally displayed, was assessed in five patients with a circumscribed lesion to either the right or left ventral visual pathway. Patients with a right, but not with a left, ventral visual lesion displayed widespread impairments in central motion perception even for non-form motion, for both slow and for fast speeds, and this held true independent of the integrity of areas MT/V5, V3A or parietal regions. In contrast with the traditional view in which only the dorsal visual stream is critical for motion perception, these novel findings implicate a more distributed circuit in which the integrity of the right ventral visual pathway is also necessary even for the perception of non-form motion. PMID:23983030

  3. Visual MRI grading system to evaluate atrophy of the supeaspinatus muscle

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    Lim, Hyun Kyoung; Hong, Sung Hwan; Yoo, Hye Jin; Choi, Ja Young; Kim, Sae Hoon; Choi, Jung Ah; Kang, Heung Sik [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2014-08-15

    To investigate the interobserver reproducibility and diagnostic feasibility of a visual grading system for assessing atrophy of the supraspinatus muscle on magnetic resonance imaging (MRI). Three independent radiologists retrospectively evaluated the occupying ratio of the supraspinatus muscle in the supraspinatus fossa on 192 shoulder MRI examinations in 188 patients using a 3-point visual grading system (1, ≥ 60%; 2, 30-59%; 3, < 30%) on oblique sagittal T1-weighted images. The inter-reader agreement and the agreement with the reference standard (3-point grades according to absolute occupying ratio values quantitatively measured by directly contouring the muscles on MRI) were analyzed using weighted kappa. The visual grading was applied by a single reader to a group of 100 consecutive patients who had undergone rotator cuff repair to retrospectively determine the association between the visual grades at preoperative state and postsurgical occurrences of retear. The inter-reader weighted kappa value for the visual grading was 0.74 when averaged across three reader pairs (0.70-0.77 for individual reader pairs). The weighted kappa value between the visual grading and the reference standard ranged from 0.75 to 0.83. There was a significant difference in retear rates of the rotator cuff between the 3 visual grades of supraspinatus muscle atrophy on MRI in univariable analysis (p < 0.001), but not in multivariable analysis (p = 0.026). The 3-point visual grading system may be a feasible method to assess the severity of supraspinatus muscle atrophy on MRI and assist in the clinical management of patients with rotator cuff tear.

  4. Visual MRI grading system to evaluate atrophy of the supeaspinatus muscle

    International Nuclear Information System (INIS)

    Lim, Hyun Kyoung; Hong, Sung Hwan; Yoo, Hye Jin; Choi, Ja Young; Kim, Sae Hoon; Choi, Jung Ah; Kang, Heung Sik

    2014-01-01

    To investigate the interobserver reproducibility and diagnostic feasibility of a visual grading system for assessing atrophy of the supraspinatus muscle on magnetic resonance imaging (MRI). Three independent radiologists retrospectively evaluated the occupying ratio of the supraspinatus muscle in the supraspinatus fossa on 192 shoulder MRI examinations in 188 patients using a 3-point visual grading system (1, ≥ 60%; 2, 30-59%; 3, < 30%) on oblique sagittal T1-weighted images. The inter-reader agreement and the agreement with the reference standard (3-point grades according to absolute occupying ratio values quantitatively measured by directly contouring the muscles on MRI) were analyzed using weighted kappa. The visual grading was applied by a single reader to a group of 100 consecutive patients who had undergone rotator cuff repair to retrospectively determine the association between the visual grades at preoperative state and postsurgical occurrences of retear. The inter-reader weighted kappa value for the visual grading was 0.74 when averaged across three reader pairs (0.70-0.77 for individual reader pairs). The weighted kappa value between the visual grading and the reference standard ranged from 0.75 to 0.83. There was a significant difference in retear rates of the rotator cuff between the 3 visual grades of supraspinatus muscle atrophy on MRI in univariable analysis (p < 0.001), but not in multivariable analysis (p = 0.026). The 3-point visual grading system may be a feasible method to assess the severity of supraspinatus muscle atrophy on MRI and assist in the clinical management of patients with rotator cuff tear.

  5. The role of visual spatial attention in audiovisual speech perception

    DEFF Research Database (Denmark)

    Andersen, Tobias; Tiippana, K.; Laarni, J.

    2009-01-01

    Auditory and visual information is integrated when perceiving speech, as evidenced by the McGurk effect in which viewing an incongruent talking face categorically alters auditory speech perception. Audiovisual integration in speech perception has long been considered automatic and pre-attentive b......Auditory and visual information is integrated when perceiving speech, as evidenced by the McGurk effect in which viewing an incongruent talking face categorically alters auditory speech perception. Audiovisual integration in speech perception has long been considered automatic and pre...... from each of the faces and from the voice on the auditory speech percept. We found that directing visual spatial attention towards a face increased the influence of that face on auditory perception. However, the influence of the voice on auditory perception did not change suggesting that audiovisual...... integration did not change. Visual spatial attention was also able to select between the faces when lip reading. This suggests that visual spatial attention acts at the level of visual speech perception prior to audiovisual integration and that the effect propagates through audiovisual integration...

  6. Visual Motion Perception and Visual Attentive Processes.

    Science.gov (United States)

    1988-04-01

    88-0551 Visual Motion Perception and Visual Attentive Processes George Spering , New YorkUnivesity A -cesson For DTIC TAB rant AFOSR 85-0364... Spering . HIPSt: A Unix-based image processing syslem. Computer Vision, Graphics, and Image Processing, 1984,25. 331-347. ’HIPS is the Human Information...Processing Laboratory’s Image Processing System. 1985 van Santen, Jan P. It, and George Spering . Elaborated Reichardt detectors. Journal of the Optical

  7. S3-1: The Serial Dependence of Visual Perception

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    David Whitney

    2012-10-01

    Full Text Available In our moment-to-moment perceptual experience, visual scenes can change, but objects rarely spontaneously come into or out of existence. The visual system may therefore delicately balance the need to optimize sensitivity to image changes (e.g., by adapting to changes in color, orientation, object identity, etc with the desire to represent the temporal continuity of objects—the likelihood that objects perceived at this moment tend to exist in subsequent moments. One way that the visual system may promote such stability is through the introduction of serial dependence to visual perception: by biasing the current percept toward what was seen at previous moments, the brain could compensate for variability in visual input that might otherwise disrupt perceptual continuity. Here, in two sets of experiments, we tested for serial dependence in visual perception of orientation and facial expression. We found that on a given trial, a subject's perception of the orientation of a grating reflected not only the currently viewed stimulus, but also a systematic attraction toward the orientations of the previously viewed stimuli. We found the same serial dependence in the perception of facial expression. This perceptual attraction extended over several trials and seconds, and displayed clear tuning to the difference (in orientation or facial expression between the sequential stimuli. Furthermore, serial dependence in object perception was spatially specific and selective to the attended object within a scene. Several control experiments showed that the perceptual serial dependence we report cannot be explained by effects of priming, known hysteresis effects, visual short-term memory, or expectation. Our results reveal a systematic influence of recent visual experiences on perception at any given moment: visual percepts, even of unambiguous stimuli, are attracted toward what was previously seen. We propose that such serial dependence helps to maintain

  8. Haptic perception disambiguates visual perception of 3D shape

    NARCIS (Netherlands)

    Wijntjes, Maarten W A; Volcic, Robert; Pont, Sylvia C.; Koenderink, Jan J.; Kappers, Astrid M L

    We studied the influence of haptics on visual perception of three-dimensional shape. Observers were shown pictures of an oblate spheroid in two different orientations. A gauge-figure task was used to measure their perception of the global shape. In the first two sessions only vision was used. The

  9. Visual perception and imagery: a new molecular hypothesis.

    Science.gov (United States)

    Bókkon, I

    2009-05-01

    Here, we put forward a redox molecular hypothesis about the natural biophysical substrate of visual perception and visual imagery. This hypothesis is based on the redox and bioluminescent processes of neuronal cells in retinotopically organized cytochrome oxidase-rich visual areas. Our hypothesis is in line with the functional roles of reactive oxygen and nitrogen species in living cells that are not part of haphazard process, but rather a very strict mechanism used in signaling pathways. We point out that there is a direct relationship between neuronal activity and the biophoton emission process in the brain. Electrical and biochemical processes in the brain represent sensory information from the external world. During encoding or retrieval of information, electrical signals of neurons can be converted into synchronized biophoton signals by bioluminescent radical and non-radical processes. Therefore, information in the brain appears not only as an electrical (chemical) signal but also as a regulated biophoton (weak optical) signal inside neurons. During visual perception, the topological distribution of photon stimuli on the retina is represented by electrical neuronal activity in retinotopically organized visual areas. These retinotopic electrical signals in visual neurons can be converted into synchronized biophoton signals by radical and non-radical processes in retinotopically organized mitochondria-rich areas. As a result, regulated bioluminescent biophotons can create intrinsic pictures (depictive representation) in retinotopically organized cytochrome oxidase-rich visual areas during visual imagery and visual perception. The long-term visual memory is interpreted as epigenetic information regulated by free radicals and redox processes. This hypothesis does not claim to solve the secret of consciousness, but proposes that the evolution of higher levels of complexity made the intrinsic picture representation of the external visual world possible by regulated

  10. The relationship between gross motor skills and visual perception of preschoolers

    OpenAIRE

    TEPELI, Kezban

    2014-01-01

    Answers were searched for these questions; “Is there a relationship between visual perceptions and gross motor skills of preschool children?”, “Are preschool children's visual perceptions predictors of their gross motor skills?”, “Is there any difference between visual perceptions of the children having low, average and high level of gross motor skills?” within this study where the relationship between preschool children's visual perceptions and their gross motor skills were compara...

  11. Visual perception of ADHD children with sensory processing disorder.

    Science.gov (United States)

    Jung, Hyerim; Woo, Young Jae; Kang, Je Wook; Choi, Yeon Woo; Kim, Kyeong Mi

    2014-04-01

    The aim of the present study was to investigate the visual perception difference between ADHD children with and without sensory processing disorder, and the relationship between sensory processing and visual perception of the children with ADHD. Participants were 47 outpatients, aged 6-8 years, diagnosed with ADHD. After excluding those who met exclusion criteria, 38 subjects were clustered into two groups, ADHD children with and without sensory processing disorder (SPD), using SSP reported by their parents, then subjects completed K-DTVP-2. Spearman correlation analysis was run to determine the relationship between sensory processing and visual perception, and Mann-Whitney-U test was conducted to compare the K-DTVP-2 score of two groups respectively. The ADHD children with SPD performed inferiorly to ADHD children without SPD in the on 3 quotients of K-DTVP-2. The GVP of K-DTVP-2 score was related to Movement Sensitivity section (r=0.368(*)) and Low Energy/Weak section of SSP (r=0.369*). The result of the present study suggests that among children with ADHD, the visual perception is lower in those children with co-morbid SPD. Also, visual perception may be related to sensory processing, especially in the reactions of vestibular and proprioceptive senses. Regarding academic performance, it is necessary to consider how sensory processing issues affect visual perception in children with ADHD.

  12. Dental anatomy grading: comparison between conventional visual and a novel digital assessment technique.

    Science.gov (United States)

    Kwon, So Ran; Restrepo-Kennedy, Natalia; Dawson, Deborah V; Hernandez, Marcela; Denehy, Gerald; Blanchette, Derek; Gratton, David G; Aquilino, Steven A; Armstrong, Steven R

    2014-12-01

    Conventional grading of dental students' projects in preclinical courses has mainly relied on visual evaluation by experienced instructors. The purpose of this study was to compare conventional visual grading in a dental anatomy course at one U.S. dental school to a novel digital assessment technique. A total of sixty samples comprised of two sets of faculty wax-ups (n=30), student wax-ups (n=15), and dentoform teeth of tooth #14 (n=15) were used for this study. Two additional faculty members visually graded the samples according to a checklist and then repeated the grading after one week. The sample wax-up with the highest score based on the visual grading was selected as the master model for the digital grading, which was also performed twice with an interim period of one week. Descriptive statistics and signed rank tests for systematic bias were used for intra- and interrater comparisons. The intraclass correlation (ICC) was used as a measure of intra- and interrater reliability. None of the faculty members achieved the minimum acceptable intrarater agreement of 0.8. Interrater agreement was substantially less than intrarater agreement for the visual grading, whereas all measures of intrarater agreement were greater than 0.9 and considered excellent for the digital assessment technique. These results suggest that visual grading is limited by modest intrarater reliability and low interrater agreement. Digital grading is a promising evaluation method showing excellent intrarater reliability and correlation. Correlation for visual and digital grading was consistently modest, partly supporting the potential use of digital technology in dental anatomy grading.

  13. Contrast and strength of visual memory and imagery differentially affect visual perception.

    Science.gov (United States)

    Saad, Elyana; Silvanto, Juha

    2013-01-01

    Visual short-term memory (VSTM) and visual imagery have been shown to modulate visual perception. However, how the subjective experience of VSTM/imagery and its contrast modulate this process has not been investigated. We addressed this issue by asking participants to detect brief masked targets while they were engaged either in VSTM or visual imagery. Subjective experience of memory/imagery (strength scale), and the visual contrast of the memory/mental image (contrast scale) were assessed on a trial-by-trial basis. For both VSTM and imagery, contrast of the memory/mental image was positively associated with reporting target presence. Consequently, at the sensory level, both VSTM and imagery facilitated visual perception. However, subjective strength of VSTM was positively associated with visual detection whereas the opposite pattern was found for imagery. Thus the relationship between subjective strength of memory/imagery and visual detection are qualitatively different for VSTM and visual imagery, although their impact at the sensory level appears similar. Our results furthermore demonstrate that imagery and VSTM are partly dissociable processes.

  14. Contrast and strength of visual memory and imagery differentially affect visual perception.

    Directory of Open Access Journals (Sweden)

    Elyana Saad

    Full Text Available Visual short-term memory (VSTM and visual imagery have been shown to modulate visual perception. However, how the subjective experience of VSTM/imagery and its contrast modulate this process has not been investigated. We addressed this issue by asking participants to detect brief masked targets while they were engaged either in VSTM or visual imagery. Subjective experience of memory/imagery (strength scale, and the visual contrast of the memory/mental image (contrast scale were assessed on a trial-by-trial basis. For both VSTM and imagery, contrast of the memory/mental image was positively associated with reporting target presence. Consequently, at the sensory level, both VSTM and imagery facilitated visual perception. However, subjective strength of VSTM was positively associated with visual detection whereas the opposite pattern was found for imagery. Thus the relationship between subjective strength of memory/imagery and visual detection are qualitatively different for VSTM and visual imagery, although their impact at the sensory level appears similar. Our results furthermore demonstrate that imagery and VSTM are partly dissociable processes.

  15. Visual perception and radiographic interpretation

    International Nuclear Information System (INIS)

    Papageorges, M.

    1998-01-01

    Although interpretation errors are common in radiology, their causes are still debated. Perceptual mechanisms appear to be responsible for a large proportion of mistakes made by both neophytes and trained radiologists. Erroneous perception of familiar contours can be triggered by unrelated opacities. Conversely, visual information cannot induce a specific perception if the observer is not familiar with the concept represented or its radiographicappearance. Additionally, the area of acute vision is smaller than is commonly recognized. Other factors, such as the attitude, beliefs,.: preconceptions, and expectations of the viewer, can affect what he or she ''sees'' whenviewing any object, including a radiograph. Familiarity with perceptual mechanisms and the limitations of the visual system as well as multiple readings may be necessary to reduce interpretation errors

  16. Does visual attention drive the dynamics of bistable perception?

    Science.gov (United States)

    Dieter, Kevin C; Brascamp, Jan; Tadin, Duje; Blake, Randolph

    2016-10-01

    How does attention interact with incoming sensory information to determine what we perceive? One domain in which this question has received serious consideration is that of bistable perception: a captivating class of phenomena that involves fluctuating visual experience in the face of physically unchanging sensory input. Here, some investigations have yielded support for the idea that attention alone determines what is seen, while others have implicated entirely attention-independent processes in driving alternations during bistable perception. We review the body of literature addressing this divide and conclude that in fact both sides are correct-depending on the form of bistable perception being considered. Converging evidence suggests that visual attention is required for alternations in the type of bistable perception called binocular rivalry, while alternations during other types of bistable perception appear to continue without requiring attention. We discuss some implications of this differential effect of attention for our understanding of the mechanisms underlying bistable perception, and examine how these mechanisms operate during our everyday visual experiences.

  17. Working memory biasing of visual perception without awareness.

    Science.gov (United States)

    Pan, Yi; Lin, Bingyuan; Zhao, Yajun; Soto, David

    2014-10-01

    Previous research has demonstrated that the contents of visual working memory can bias visual processing in favor of matching stimuli in the scene. However, the extent to which such top-down, memory-driven biasing of visual perception is contingent on conscious awareness remains unknown. Here we showed that conscious awareness of critical visual cues is dispensable for working memory to bias perceptual selection mechanisms. Using the procedure of continuous flash suppression, we demonstrated that "unseen" visual stimuli during interocular suppression can gain preferential access to awareness if they match the contents of visual working memory. Strikingly, the very same effect occurred even when the visual cue to be held in memory was rendered nonconscious by masking. Control experiments ruled out the alternative accounts of repetition priming and different detection criteria. We conclude that working memory biases of visual perception can operate in the absence of conscious awareness.

  18. From humans to computers cognition through visual perception

    CERN Document Server

    Alexandrov, Viktor Vasilievitch

    1991-01-01

    This book considers computer vision to be an integral part of the artificial intelligence system. The core of the book is an analysis of possible approaches to the creation of artificial vision systems, which simulate human visual perception. Much attention is paid to the latest achievements in visual psychology and physiology, the description of the functional and structural organization of the human perception mechanism, the peculiarities of artistic perception and the expression of reality. Computer vision models based on these data are investigated. They include the processes of external d

  19. The development of visual speech perception in Mandarin Chinese-speaking children.

    Science.gov (United States)

    Chen, Liang; Lei, Jianghua

    2017-01-01

    The present study aimed to investigate the development of visual speech perception in Chinese-speaking children. Children aged 7, 13 and 16 were asked to visually identify both consonant and vowel sounds in Chinese as quickly and accurately as possible. Results revealed (1) an increase in accuracy of visual speech perception between ages 7 and 13 after which the accuracy rate either stagnates or drops; and (2) a U-shaped development pattern in speed of perception with peak performance in 13-year olds. Results also showed that across all age groups, the overall levels of accuracy rose, whereas the response times fell for simplex finals, complex finals and initials. These findings suggest that (1) visual speech perception in Chinese is a developmental process that is acquired over time and is still fine-tuned well into late adolescence; (2) factors other than cross-linguistic differences in phonological complexity and degrees of reliance on visual information are involved in development of visual speech perception.

  20. Visual and auditory perception in preschool children at risk for dyslexia.

    Science.gov (United States)

    Ortiz, Rosario; Estévez, Adelina; Muñetón, Mercedes; Domínguez, Carolina

    2014-11-01

    Recently, there has been renewed interest in perceptive problems of dyslexics. A polemic research issue in this area has been the nature of the perception deficit. Another issue is the causal role of this deficit in dyslexia. Most studies have been carried out in adult and child literates; consequently, the observed deficits may be the result rather than the cause of dyslexia. This study addresses these issues by examining visual and auditory perception in children at risk for dyslexia. We compared children from preschool with and without risk for dyslexia in auditory and visual temporal order judgment tasks and same-different discrimination tasks. Identical visual and auditory, linguistic and nonlinguistic stimuli were presented in both tasks. The results revealed that the visual as well as the auditory perception of children at risk for dyslexia is impaired. The comparison between groups in auditory and visual perception shows that the achievement of children at risk was lower than children without risk for dyslexia in the temporal tasks. There were no differences between groups in auditory discrimination tasks. The difficulties of children at risk in visual and auditory perceptive processing affected both linguistic and nonlinguistic stimuli. Our conclusions are that children at risk for dyslexia show auditory and visual perceptive deficits for linguistic and nonlinguistic stimuli. The auditory impairment may be explained by temporal processing problems and these problems are more serious for processing language than for processing other auditory stimuli. These visual and auditory perceptive deficits are not the consequence of failing to learn to read, thus, these findings support the theory of temporal processing deficit. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Neural mechanisms underlying temporal modulation of visual perception

    NARCIS (Netherlands)

    Jong, M.C. de

    2015-01-01

    However confident we feel about the way we perceive the visual world around us, there is not a one-to-one relation between visual stimulation and visual perception. Our eyes register reflections of the visual environment and our brain has the difficult task of constructing ‘reality’ from this

  2. Adaptive optics without altering visual perception.

    Science.gov (United States)

    Koenig, D E; Hart, N W; Hofer, H J

    2014-04-01

    Adaptive optics combined with visual psychophysics creates the potential to study the relationship between visual function and the retina at the cellular scale. This potential is hampered, however, by visual interference from the wavefront-sensing beacon used during correction. For example, we have previously shown that even a dim, visible beacon can alter stimulus perception (Hofer et al., 2012). Here we describe a simple strategy employing a longer wavelength (980nm) beacon that, in conjunction with appropriate restriction on timing and placement, allowed us to perform psychophysics when dark adapted without altering visual perception. The method was verified by comparing detection and color appearance of foveally presented small spot stimuli with and without the wavefront beacon present in 5 subjects. As an important caution, we found that significant perceptual interference can occur even with a subliminal beacon when additional measures are not taken to limit exposure. Consequently, the lack of perceptual interference should be verified for a given system, and not assumed based on invisibility of the beacon. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Eye movements and attention in reading, scene perception, and visual search.

    Science.gov (United States)

    Rayner, Keith

    2009-08-01

    Eye movements are now widely used to investigate cognitive processes during reading, scene perception, and visual search. In this article, research on the following topics is reviewed with respect to reading: (a) the perceptual span (or span of effective vision), (b) preview benefit, (c) eye movement control, and (d) models of eye movements. Related issues with respect to eye movements during scene perception and visual search are also reviewed. It is argued that research on eye movements during reading has been somewhat advanced over research on eye movements in scene perception and visual search and that some of the paradigms developed to study reading should be more widely adopted in the study of scene perception and visual search. Research dealing with "real-world" tasks and research utilizing the visual-world paradigm are also briefly discussed.

  4. Visual perception and memory systems: from cortex to medial temporal lobe.

    Science.gov (United States)

    Khan, Zafar U; Martín-Montañez, Elisa; Baxter, Mark G

    2011-05-01

    Visual perception and memory are the most important components of vision processing in the brain. It was thought that the perceptual aspect of a visual stimulus occurs in visual cortical areas and that this serves as the substrate for the formation of visual memory in a distinct part of the brain called the medial temporal lobe. However, current evidence indicates that there is no functional separation of areas. Entire visual cortical pathways and connecting medial temporal lobe are important for both perception and visual memory. Though some aspects of this view are debated, evidence from both sides will be explored here. In this review, we will discuss the anatomical and functional architecture of the entire system and the implications of these structures in visual perception and memory.

  5. Contrast and Strength of Visual Memory and Imagery Differentially Affect Visual Perception

    OpenAIRE

    Saad, Elyana; Silvanto, Juha

    2013-01-01

    Visual short-term memory (VSTM) and visual imagery have been shown to modulate visual perception. However, how the subjective experience of VSTM/imagery and its contrast modulate this process has not been investigated. We addressed this issue by asking participants to detect brief masked targets while they were engaged either in VSTM or visual imagery. Subjective experience of memory/imagery (strength scale), and the visual contrast of the memory/mental image (contrast scale) were assessed on...

  6. Attentional episodes in visual perception

    NARCIS (Netherlands)

    Wyble, Brad; Potter, Mary C.; Bowman, Howard; Nieuwenstein, Mark

    Is one's temporal perception of the world truly as seamless as it appears? This article presents a computationally motivated theory suggesting that visual attention samples information from temporal episodes (episodic simultaneous type/serial token model; Wyble, Bowman, & Nieuwenstein, 2009). Breaks

  7. Visual working memory contaminates perception

    OpenAIRE

    Kang, Min-Suk; Hong, Sang Wook; Blake, Randolph; Woodman, Geoffrey F.

    2011-01-01

    Indirect evidence suggests that the contents of visual working memory may be maintained within sensory areas early in the visual hierarchy. We tested this possibility using a well-studied motion repulsion phenomenon in which perception of one direction of motion is distorted when another direction of motion is viewed simultaneously. We found that observers misperceived the actual direction of motion of a single motion stimulus if, while viewing that stimulus, they were holding a different mot...

  8. Human Occipital and Parietal GABA Selectively Influence Visual Perception of Orientation and Size.

    Science.gov (United States)

    Song, Chen; Sandberg, Kristian; Andersen, Lau Møller; Blicher, Jakob Udby; Rees, Geraint

    2017-09-13

    GABA is the primary inhibitory neurotransmitter in human brain. The level of GABA varies substantially across individuals, and this variability is associated with interindividual differences in visual perception. However, it remains unclear whether the association between GABA level and visual perception reflects a general influence of visual inhibition or whether the GABA levels of different cortical regions selectively influence perception of different visual features. To address this, we studied how the GABA levels of parietal and occipital cortices related to interindividual differences in size, orientation, and brightness perception. We used visual contextual illusion as a perceptual assay since the illusion dissociates perceptual content from stimulus content and the magnitude of the illusion reflects the effect of visual inhibition. Across individuals, we observed selective correlations between the level of GABA and the magnitude of contextual illusion. Specifically, parietal GABA level correlated with size illusion magnitude but not with orientation or brightness illusion magnitude; in contrast, occipital GABA level correlated with orientation illusion magnitude but not with size or brightness illusion magnitude. Our findings reveal a region- and feature-dependent influence of GABA level on human visual perception. Parietal and occipital cortices contain, respectively, topographic maps of size and orientation preference in which neural responses to stimulus sizes and stimulus orientations are modulated by intraregional lateral connections. We propose that these lateral connections may underlie the selective influence of GABA on visual perception. SIGNIFICANCE STATEMENT GABA, the primary inhibitory neurotransmitter in human visual system, varies substantially across individuals. This interindividual variability in GABA level is linked to interindividual differences in many aspects of visual perception. However, the widespread influence of GABA raises the

  9. Human Occipital and Parietal GABA Selectively Influence Visual Perception of Orientation and Size

    Science.gov (United States)

    Andersen, Lau Møller; Blicher, Jakob Udby

    2017-01-01

    GABA is the primary inhibitory neurotransmitter in human brain. The level of GABA varies substantially across individuals, and this variability is associated with interindividual differences in visual perception. However, it remains unclear whether the association between GABA level and visual perception reflects a general influence of visual inhibition or whether the GABA levels of different cortical regions selectively influence perception of different visual features. To address this, we studied how the GABA levels of parietal and occipital cortices related to interindividual differences in size, orientation, and brightness perception. We used visual contextual illusion as a perceptual assay since the illusion dissociates perceptual content from stimulus content and the magnitude of the illusion reflects the effect of visual inhibition. Across individuals, we observed selective correlations between the level of GABA and the magnitude of contextual illusion. Specifically, parietal GABA level correlated with size illusion magnitude but not with orientation or brightness illusion magnitude; in contrast, occipital GABA level correlated with orientation illusion magnitude but not with size or brightness illusion magnitude. Our findings reveal a region- and feature-dependent influence of GABA level on human visual perception. Parietal and occipital cortices contain, respectively, topographic maps of size and orientation preference in which neural responses to stimulus sizes and stimulus orientations are modulated by intraregional lateral connections. We propose that these lateral connections may underlie the selective influence of GABA on visual perception. SIGNIFICANCE STATEMENT GABA, the primary inhibitory neurotransmitter in human visual system, varies substantially across individuals. This interindividual variability in GABA level is linked to interindividual differences in many aspects of visual perception. However, the widespread influence of GABA raises the

  10. Visual Perception with Color for Architectural Aesthetics

    NARCIS (Netherlands)

    Bittermann, M.S.; Ciftcioglu, O.

    2016-01-01

    Studies on computer-based visual perception and aesthetical judgment for architectural design are presented. In the model, both color and the geometric aspects of human vision are jointly taken into account, quantifying the perception of an individual object, as well as a scene consisting of several

  11. Direct Contribution of Auditory Motion Information to Sound-Induced Visual Motion Perception

    Directory of Open Access Journals (Sweden)

    Souta Hidaka

    2011-10-01

    Full Text Available We have recently demonstrated that alternating left-right sound sources induce motion perception to static visual stimuli along the horizontal plane (SIVM: sound-induced visual motion perception, Hidaka et al., 2009. The aim of the current study was to elucidate whether auditory motion signals, rather than auditory positional signals, can directly contribute to the SIVM. We presented static visual flashes at retinal locations outside the fovea together with a lateral auditory motion provided by a virtual stereo noise source smoothly shifting in the horizontal plane. The flashes appeared to move in the situation where auditory positional information would have little influence on the perceived position of visual stimuli; the spatiotemporal position of the flashes was in the middle of the auditory motion trajectory. Furthermore, the auditory motion altered visual motion perception in a global motion display; in this display, different localized motion signals of multiple visual stimuli were combined to produce a coherent visual motion perception so that there was no clear one-to-one correspondence between the auditory stimuli and each visual stimulus. These findings suggest the existence of direct interactions between the auditory and visual modalities in motion processing and motion perception.

  12. Visual working memory contaminates perception.

    Science.gov (United States)

    Kang, Min-Suk; Hong, Sang Wook; Blake, Randolph; Woodman, Geoffrey F

    2011-10-01

    Indirect evidence suggests that the contents of visual working memory may be maintained within sensory areas early in the visual hierarchy. We tested this possibility using a well-studied motion repulsion phenomenon in which perception of one direction of motion is distorted when another direction of motion is viewed simultaneously. We found that observers misperceived the actual direction of motion of a single motion stimulus if, while viewing that stimulus, they were holding a different motion direction in visual working memory. Control experiments showed that none of a variety of alternative explanations could account for this repulsion effect induced by working memory. Our findings provide compelling evidence that visual working memory representations directly interact with the same neural mechanisms as those involved in processing basic sensory events.

  13. Making Information Visual: Seventh Grade Art Information and Visual Literacy

    Science.gov (United States)

    Shoemaker, Joel; Schau, Elizabeth; Ayers, Rachael

    2008-01-01

    Seventh grade students entering South East Junior High in Iowa City come from eight elementary feeder schools, as well as from schools around the world. Their information literacy skills and knowledge of reference sources vary, but since all seventh graders and new eighth graders are required to take one trimester of Visual Studies, all entering…

  14. Auditory, visual, and auditory-visual perceptions of emotions by young children with hearing loss versus children with normal hearing.

    Science.gov (United States)

    Most, Tova; Michaelis, Hilit

    2012-08-01

    This study aimed to investigate the effect of hearing loss (HL) on emotion-perception ability among young children with and without HL. A total of 26 children 4.0-6.6 years of age with prelingual sensory-neural HL ranging from moderate to profound and 14 children with normal hearing (NH) participated. They were asked to identify happiness, anger, sadness, and fear expressed by an actress when uttering the same neutral nonsense sentence. Their auditory, visual, and auditory-visual perceptions of the emotional content were assessed. The accuracy of emotion perception among children with HL was lower than that of the NH children in all 3 conditions: auditory, visual, and auditory-visual. Perception through the combined auditory-visual mode significantly surpassed the auditory or visual modes alone in both groups, indicating that children with HL utilized the auditory information for emotion perception. No significant differences in perception emerged according to degree of HL. In addition, children with profound HL and cochlear implants did not perform differently from children with less severe HL who used hearing aids. The relatively high accuracy of emotion perception by children with HL may be explained by their intensive rehabilitation, which emphasizes suprasegmental and paralinguistic aspects of verbal communication.

  15. Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

    Science.gov (United States)

    Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

  16. Impact of coated windows on visual perception

    DEFF Research Database (Denmark)

    Johnsen, Kjeld; Dubois, Marie-Claude

    of brightness and colours in a space. Overall, the study shows that coated glazings may moderately affect the perception details, slightly affect the perception of glare from window and do not affect the perception of shadows on and around objects in the room. The results also suggest that the perception...... of brightness and other visual aspects such as sharpness, details, character, etc., seem to be a complex function of the intensity and colour of the transmitted light and is not solely and linearly dependent on the glazing light transmittance....

  17. Vividness of Visual Imagery Depends on the Neural Overlap with Perception in Visual Areas.

    Science.gov (United States)

    Dijkstra, Nadine; Bosch, Sander E; van Gerven, Marcel A J

    2017-02-01

    Research into the neural correlates of individual differences in imagery vividness point to an important role of the early visual cortex. However, there is also great fluctuation of vividness within individuals, such that only looking at differences between people necessarily obscures the picture. In this study, we show that variation in moment-to-moment experienced vividness of visual imagery, within human subjects, depends on the activity of a large network of brain areas, including frontal, parietal, and visual areas. Furthermore, using a novel multivariate analysis technique, we show that the neural overlap between imagery and perception in the entire visual system correlates with experienced imagery vividness. This shows that the neural basis of imagery vividness is much more complicated than studies of individual differences seemed to suggest. Visual imagery is the ability to visualize objects that are not in our direct line of sight: something that is important for memory, spatial reasoning, and many other tasks. It is known that the better people are at visual imagery, the better they can perform these tasks. However, the neural correlates of moment-to-moment variation in visual imagery remain unclear. In this study, we show that the more the neural response during imagery is similar to the neural response during perception, the more vivid or perception-like the imagery experience is. Copyright © 2017 the authors 0270-6474/17/371367-07$15.00/0.

  18. Improving visual perception through neurofeedback

    Science.gov (United States)

    Scharnowski, Frank; Hutton, Chloe; Josephs, Oliver; Weiskopf, Nikolaus; Rees, Geraint

    2012-01-01

    Perception depends on the interplay of ongoing spontaneous activity and stimulus-evoked activity in sensory cortices. This raises the possibility that training ongoing spontaneous activity alone might be sufficient for enhancing perceptual sensitivity. To test this, we trained human participants to control ongoing spontaneous activity in circumscribed regions of retinotopic visual cortex using real-time functional MRI based neurofeedback. After training, we tested participants using a new and previously untrained visual detection task that was presented at the visual field location corresponding to the trained region of visual cortex. Perceptual sensitivity was significantly enhanced only when participants who had previously learned control over ongoing activity were now exercising control, and only for that region of visual cortex. Our new approach allows us to non-invasively and non-pharmacologically manipulate regionally specific brain activity, and thus provide ‘brain training’ to deliver particular perceptual enhancements. PMID:23223302

  19. Effect of Size Change and Brightness Change of Visual Stimuli on Loudness Perception and Pitch Perception of Auditory Stimuli

    Directory of Open Access Journals (Sweden)

    Syouya Tanabe

    2011-10-01

    Full Text Available People obtain a lot of information from visual and auditory sensation on daily life. Regarding the effect of visual stimuli on perception of auditory stimuli, studies of phonological perception and sound localization have been made in great numbers. This study examined the effect of visual stimuli on perception in loudness and pitch of auditory stimuli. We used the image of figures whose size or brightness was changed as visual stimuli, and the sound of pure tone whose loudness or pitch was changed as auditory stimuli. Those visual and auditory stimuli were combined independently to make four types of audio-visual multisensory stimuli for psychophysical experiments. In the experiments, participants judged change in loudness or pitch of auditory stimuli, while they judged the direction of size change or the kind of a presented figure in visual stimuli. Therefore they cannot neglect visual stimuli while they judged auditory stimuli. As a result, perception in loudness and pitch were promoted significantly around their difference limen, when the image was getting bigger or brighter, compared with the case in which the image had no changes. This indicates that perception in loudness and pitch were affected by change in size and brightness of visual stimuli.

  20. Visual Perception Based Rate Control Algorithm for HEVC

    Science.gov (United States)

    Feng, Zeqi; Liu, PengYu; Jia, Kebin

    2018-01-01

    For HEVC, rate control is an indispensably important video coding technology to alleviate the contradiction between video quality and the limited encoding resources during video communication. However, the rate control benchmark algorithm of HEVC ignores subjective visual perception. For key focus regions, bit allocation of LCU is not ideal and subjective quality is unsatisfied. In this paper, a visual perception based rate control algorithm for HEVC is proposed. First bit allocation weight of LCU level is optimized based on the visual perception of luminance and motion to ameliorate video subjective quality. Then λ and QP are adjusted in combination with the bit allocation weight to improve rate distortion performance. Experimental results show that the proposed algorithm reduces average 0.5% BD-BR and maximum 1.09% BD-BR at no cost in bitrate accuracy compared with HEVC (HM15.0). The proposed algorithm devotes to improving video subjective quality under various video applications.

  1. The effect of phasic auditory alerting on visual perception.

    Science.gov (United States)

    Petersen, Anders; Petersen, Annemarie Hilkjær; Bundesen, Claus; Vangkilde, Signe; Habekost, Thomas

    2017-08-01

    Phasic alertness refers to a short-lived change in the preparatory state of the cognitive system following an alerting signal. In the present study, we examined the effect of phasic auditory alerting on distinct perceptual processes, unconfounded by motor components. We combined an alerting/no-alerting design with a pure accuracy-based single-letter recognition task. Computational modeling based on Bundesen's Theory of Visual Attention was used to examine the effect of phasic alertness on visual processing speed and threshold of conscious perception. Results show that phasic auditory alertness affects visual perception by increasing the visual processing speed and lowering the threshold of conscious perception (Experiment 1). By manipulating the intensity of the alerting cue, we further observed a positive relationship between alerting intensity and processing speed, which was not seen for the threshold of conscious perception (Experiment 2). This was replicated in a third experiment, in which pupil size was measured as a physiological marker of alertness. Results revealed that the increase in processing speed was accompanied by an increase in pupil size, substantiating the link between alertness and processing speed (Experiment 3). The implications of these results are discussed in relation to a newly developed mathematical model of the relationship between levels of alertness and the speed with which humans process visual information. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Novelty enhances visual perception.

    Directory of Open Access Journals (Sweden)

    Judith Schomaker

    Full Text Available The effects of novelty on low-level visual perception were investigated in two experiments using a two-alternative forced-choice tilt detection task. A target, consisting of a Gabor patch, was preceded by a cue that was either a novel or a familiar fractal image. Participants had to indicate whether the Gabor stimulus was vertically oriented or slightly tilted. In the first experiment tilt angle was manipulated; in the second contrast of the Gabor patch was varied. In the first, we found that sensitivity was enhanced after a novel compared to a familiar cue, and in the second we found sensitivity to be enhanced for novel cues in later experimental blocks when participants became more and more familiarized with the familiar cue. These effects were not caused by a shift in the response criterion. This shows for the first time that novel stimuli affect low-level characteristics of perception. We suggest that novelty can elicit a transient attentional response, thereby enhancing perception.

  3. Novelty enhances visual perception.

    Science.gov (United States)

    Schomaker, Judith; Meeter, Martijn

    2012-01-01

    The effects of novelty on low-level visual perception were investigated in two experiments using a two-alternative forced-choice tilt detection task. A target, consisting of a Gabor patch, was preceded by a cue that was either a novel or a familiar fractal image. Participants had to indicate whether the Gabor stimulus was vertically oriented or slightly tilted. In the first experiment tilt angle was manipulated; in the second contrast of the Gabor patch was varied. In the first, we found that sensitivity was enhanced after a novel compared to a familiar cue, and in the second we found sensitivity to be enhanced for novel cues in later experimental blocks when participants became more and more familiarized with the familiar cue. These effects were not caused by a shift in the response criterion. This shows for the first time that novel stimuli affect low-level characteristics of perception. We suggest that novelty can elicit a transient attentional response, thereby enhancing perception.

  4. Odors Bias Time Perception in Visual and Auditory Modalities.

    Science.gov (United States)

    Yue, Zhenzhu; Gao, Tianyu; Chen, Lihan; Wu, Jiashuang

    2016-01-01

    Previous studies have shown that emotional states alter our perception of time. However, attention, which is modulated by a number of factors, such as emotional events, also influences time perception. To exclude potential attentional effects associated with emotional events, various types of odors (inducing different levels of emotional arousal) were used to explore whether olfactory events modulated time perception differently in visual and auditory modalities. Participants were shown either a visual dot or heard a continuous tone for 1000 or 4000 ms while they were exposed to odors of jasmine, lavender, or garlic. Participants then reproduced the temporal durations of the preceding visual or auditory stimuli by pressing the spacebar twice. Their reproduced durations were compared to those in the control condition (without odor). The results showed that participants produced significantly longer time intervals in the lavender condition than in the jasmine or garlic conditions. The overall influence of odor on time perception was equivalent for both visual and auditory modalities. The analysis of the interaction effect showed that participants produced longer durations than the actual duration in the short interval condition, but they produced shorter durations in the long interval condition. The effect sizes were larger for the auditory modality than those for the visual modality. Moreover, by comparing performance across the initial and the final blocks of the experiment, we found odor adaptation effects were mainly manifested as longer reproductions for the short time interval later in the adaptation phase, and there was a larger effect size in the auditory modality. In summary, the present results indicate that odors imposed differential impacts on reproduced time durations, and they were constrained by different sensory modalities, valence of the emotional events, and target durations. Biases in time perception could be accounted for by a framework of

  5. Visual body perception in anorexia nervosa.

    Science.gov (United States)

    Urgesi, Cosimo; Fornasari, Livia; Perini, Laura; Canalaz, Francesca; Cremaschi, Silvana; Faleschini, Laura; Balestrieri, Matteo; Fabbro, Franco; Aglioti, Salvatore Maria; Brambilla, Paolo

    2012-05-01

    Disturbance of body perception is a central aspect of anorexia nervosa (AN) and several neuroimaging studies have documented structural and functional alterations of occipito-temporal cortices involved in visual body processing. However, it is unclear whether these perceptual deficits involve more basic aspects of others' body perception. A consecutive sample of 15 adolescent patients with AN were compared with a group of 15 age- and gender-matched controls in delayed matching to sample tasks requiring the visual discrimination of the form or of the action of others' body. Patients showed better visual discrimination performance than controls in detail-based processing of body forms but not of body actions, which positively correlated with their increased tendency to convert a signal of punishment into a signal of reinforcement (higher persistence scores). The paradoxical advantage of patients with AN in detail-based body processing may be associated to their tendency to routinely explore body parts as a consequence of their obsessive worries about body appearance. Copyright © 2012 Wiley Periodicals, Inc.

  6. Audiovisual associations alter the perception of low-level visual motion

    Directory of Open Access Journals (Sweden)

    Hulusi eKafaligonul

    2015-03-01

    Full Text Available Motion perception is a pervasive nature of vision and is affected by both immediate pattern of sensory inputs and prior experiences acquired through associations. Recently, several studies reported that an association can be established quickly between directions of visual motion and static sounds of distinct frequencies. After the association is formed, sounds are able to change the perceived direction of visual motion. To determine whether such rapidly acquired audiovisual associations and their subsequent influences on visual motion perception are dependent on the involvement of higher-order attentive tracking mechanisms, we designed psychophysical experiments using regular and reverse-phi random dot motions isolating low-level pre-attentive motion processing. Our results show that an association between the directions of low-level visual motion and static sounds can be formed and this audiovisual association alters the subsequent perception of low-level visual motion. These findings support the view that audiovisual associations are not restricted to high-level attention based motion system and early-level visual motion processing has some potential role.

  7. Cognitive impairments in patients with low grade gliomas and high grade gliomas

    Directory of Open Access Journals (Sweden)

    Eliane C. Miotto

    2011-08-01

    Full Text Available OBJECTIVE: The relationship between brain tumors and cognitive deficits is well established in the literature. However, studies investigating the cognitive status in low and high-grade gliomas patients are scarce, particularly in patients with average or lower educational level. This study aimed at investigating the cognitive functioning in a sample of patients with low and high-grade gliomas before surgical intervention. METHOD: The low-grade (G1, n=19 and high-grade glioma (G2, n=8 patients underwent a detailed neuropsychological assessment of memory, executive functions, visuo-perceptive and visuo-spatial abilities, intellectual level and language. RESULTS: There was a significant impairment on verbal and visual episodic memory, executive functions including mental flexibility, nominal and categorical verbal fluency and speed of information processing in G2. G1 showed only specific deficits on verbal and visual memory recall, mental flexibility and processing speed. CONCLUSION: These findings demonstrated different levels of impairments in the executive and memory domains in patients with low and high grade gliomas.

  8. Separate visual representations for perception and for visually guided behavior

    Science.gov (United States)

    Bridgeman, Bruce

    1989-01-01

    Converging evidence from several sources indicates that two distinct representations of visual space mediate perception and visually guided behavior, respectively. The two maps of visual space follow different rules; spatial values in either one can be biased without affecting the other. Ordinarily the two maps give equivalent responses because both are veridically in register with the world; special techniques are required to pull them apart. One such technique is saccadic suppression: small target displacements during saccadic eye movements are not preceived, though the displacements can change eye movements or pointing to the target. A second way to separate cognitive and motor-oriented maps is with induced motion: a slowly moving frame will make a fixed target appear to drift in the opposite direction, while motor behavior toward the target is unchanged. The same result occurs with stroboscopic induced motion, where the frame jump abruptly and the target seems to jump in the opposite direction. A third method of separating cognitive and motor maps, requiring no motion of target, background or eye, is the Roelofs effect: a target surrounded by an off-center rectangular frame will appear to be off-center in the direction opposite the frame. Again the effect influences perception, but in half of the subjects it does not influence pointing to the target. This experience also reveals more characteristics of the maps and their interactions with one another, the motor map apparently has little or no memory, and must be fed from the biased cognitive map if an enforced delay occurs between stimulus presentation and motor response. In designing spatial displays, the results mean that what you see isn't necessarily what you get. Displays must be designed with either perception or visually guided behavior in mind.

  9. A Comparative Study on the Visual Perceptions of Children with Attention Deficit Hyperactivity Disorder

    Science.gov (United States)

    Ahmetoglu, Emine; Aral, Neriman; Butun Ayhan, Aynur

    This study was conducted in order to (a) compare the visual perceptions of seven-year-old children diagnosed with attention deficit hyperactivity disorder with those of normally developing children of the same age and development level and (b) determine whether the visual perceptions of children with attention deficit hyperactivity disorder vary with respect to gender, having received preschool education and parents` educational level. A total of 60 children, 30 with attention deficit hyperactivity disorder and 30 with normal development, were assigned to the study. Data about children with attention deficit hyperactivity disorder and their families was collected by using a General Information Form and the visual perception of children was examined through the Frostig Developmental Test of Visual Perception. The Mann-Whitney U-test and Kruskal-Wallis variance analysis was used to determine whether there was a difference of between the visual perceptions of children with normal development and those diagnosed with attention deficit hyperactivity disorder and to discover whether the variables of gender, preschool education and parents` educational status affected the visual perceptions of children with attention deficit hyperactivity disorder. The results showed that there was a statistically meaningful difference between the visual perceptions of the two groups and that the visual perceptions of children with attention deficit hyperactivity disorder were affected meaningfully by gender, preschool education and parents` educational status.

  10. Visual Temporal Acuity Is Related to Auditory Speech Perception Abilities in Cochlear Implant Users.

    Science.gov (United States)

    Jahn, Kelly N; Stevenson, Ryan A; Wallace, Mark T

    Despite significant improvements in speech perception abilities following cochlear implantation, many prelingually deafened cochlear implant (CI) recipients continue to rely heavily on visual information to develop speech and language. Increased reliance on visual cues for understanding spoken language could lead to the development of unique audiovisual integration and visual-only processing abilities in these individuals. Brain imaging studies have demonstrated that good CI performers, as indexed by auditory-only speech perception abilities, have different patterns of visual cortex activation in response to visual and auditory stimuli as compared with poor CI performers. However, no studies have examined whether speech perception performance is related to any type of visual processing abilities following cochlear implantation. The purpose of the present study was to provide a preliminary examination of the relationship between clinical, auditory-only speech perception tests, and visual temporal acuity in prelingually deafened adult CI users. It was hypothesized that prelingually deafened CI users, who exhibit better (i.e., more acute) visual temporal processing abilities would demonstrate better auditory-only speech perception performance than those with poorer visual temporal acuity. Ten prelingually deafened adult CI users were recruited for this study. Participants completed a visual temporal order judgment task to quantify visual temporal acuity. To assess auditory-only speech perception abilities, participants completed the consonant-nucleus-consonant word recognition test and the AzBio sentence recognition test. Results were analyzed using two-tailed partial Pearson correlations, Spearman's rho correlations, and independent samples t tests. Visual temporal acuity was significantly correlated with auditory-only word and sentence recognition abilities. In addition, proficient CI users, as assessed via auditory-only speech perception performance, demonstrated

  11. Image Visual Realism: From Human Perception to Machine Computation.

    Science.gov (United States)

    Fan, Shaojing; Ng, Tian-Tsong; Koenig, Bryan L; Herberg, Jonathan S; Jiang, Ming; Shen, Zhiqi; Zhao, Qi

    2017-08-30

    Visual realism is defined as the extent to which an image appears to people as a photo rather than computer generated. Assessing visual realism is important in applications like computer graphics rendering and photo retouching. However, current realism evaluation approaches use either labor-intensive human judgments or automated algorithms largely dependent on comparing renderings to reference images. We develop a reference-free computational framework for visual realism prediction to overcome these constraints. First, we construct a benchmark dataset of 2520 images with comprehensive human annotated attributes. From statistical modeling on this data, we identify image attributes most relevant for visual realism. We propose both empirically-based (guided by our statistical modeling of human data) and CNN-learned features to predict visual realism of images. Our framework has the following advantages: (1) it creates an interpretable and concise empirical model that characterizes human perception of visual realism; (2) it links computational features to latent factors of human image perception.

  12. Odors bias time perception in visual and auditory modalities

    Directory of Open Access Journals (Sweden)

    Zhenzhu eYue

    2016-04-01

    Full Text Available Previous studies have shown that emotional states alter our perception of time. However, attention, which is modulated by a number of factors, such as emotional events, also influences time perception. To exclude potential attentional effects associated with emotional events, various types of odors (inducing different levels of emotional arousal were used to explore whether olfactory events modulated time perception differently in visual and auditory modalities. Participants were shown either a visual dot or heard a continuous tone for 1000 ms or 4000 ms while they were exposed to odors of jasmine, lavender, or garlic. Participants then reproduced the temporal durations of the preceding visual or auditory stimuli by pressing the spacebar twice. Their reproduced durations were compared to those in the control condition (without odor. The results showed that participants produced significantly longer time intervals in the lavender condition than in the jasmine or garlic conditions. The overall influence of odor on time perception was equivalent for both visual and auditory modalities. The analysis of the interaction effect showed that participants produced longer durations than the actual duration in the short interval condition, but they produced shorter durations in the long interval condition. The effect sizes were larger for the auditory modality than those for the visual modality. Moreover, by comparing performance across the initial and the final blocks of the experiment, we found odor adaptation effects were mainly manifested as longer reproductions for the short time interval later in the adaptation phase, and there was a larger effect size in the auditory modality. In summary, the present results indicate that odors imposed differential impacts on reproduced time durations, and they were constrained by different sensory modalities, valence of the emotional events, and target durations. Biases in time perception could be accounted for by a

  13. Ambiguities and conventions in the perception of visual art.

    Science.gov (United States)

    Mamassian, Pascal

    2008-09-01

    Vision perception is ambiguous and visual arts play with these ambiguities. While perceptual ambiguities are resolved with prior constraints, artistic ambiguities are resolved by conventions. Is there a relationship between priors and conventions? This review surveys recent work related to these ambiguities in composition, spatial scale, illumination and color, three-dimensional layout, shape, and movement. While most conventions seem to have their roots in perceptual constraints, those conventions that differ from priors may help us appreciate how visual arts differ from everyday perception.

  14. Public health nurse perceptions of Omaha System data visualization.

    Science.gov (United States)

    Lee, Seonah; Kim, Era; Monsen, Karen A

    2015-10-01

    Electronic health records (EHRs) provide many benefits related to the storage, deployment, and retrieval of large amounts of patient data. However, EHRs have not fully met the need to reuse data for decision making on follow-up care plans. Visualization offers new ways to present health data, especially in EHRs. Well-designed data visualization allows clinicians to communicate information efficiently and effectively, contributing to improved interpretation of clinical data and better patient care monitoring and decision making. Public health nurse (PHN) perceptions of Omaha System data visualization prototypes for use in EHRs have not been evaluated. To visualize PHN-generated Omaha System data and assess PHN perceptions regarding the visual validity, helpfulness, usefulness, and importance of the visualizations, including interactive functionality. Time-oriented visualization for problems and outcomes and Matrix visualization for problems and interventions were developed using PHN-generated Omaha System data to help PHNs consume data and plan care at the point of care. Eleven PHNs evaluated prototype visualizations. Overall PHNs response to visualizations was positive, and feedback for improvement was provided. This study demonstrated the potential for using visualization techniques within EHRs to summarize Omaha System patient data for clinicians. Further research is needed to improve and refine these visualizations and assess the potential to incorporate visualizations within clinical EHRs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Dynamic Stimuli And Active Processing In Human Visual Perception

    Science.gov (United States)

    Haber, Ralph N.

    1990-03-01

    Theories of visual perception traditionally have considered a static retinal image to be the starting point for processing; and has considered processing both to be passive and a literal translation of that frozen, two dimensional, pictorial image. This paper considers five problem areas in the analysis of human visually guided locomotion, in which the traditional approach is contrasted to newer ones that utilize dynamic definitions of stimulation, and an active perceiver: (1) differentiation between object motion and self motion, and among the various kinds of self motion (e.g., eyes only, head only, whole body, and their combinations); (2) the sources and contents of visual information that guide movement; (3) the acquisition and performance of perceptual motor skills; (4) the nature of spatial representations, percepts, and the perceived layout of space; and (5) and why the retinal image is a poor starting point for perceptual processing. These newer approaches argue that stimuli must be considered as dynamic: humans process the systematic changes in patterned light when objects move and when they themselves move. Furthermore, the processing of visual stimuli must be active and interactive, so that perceivers can construct panoramic and stable percepts from an interaction of stimulus information and expectancies of what is contained in the visual environment. These developments all suggest a very different approach to the computational analyses of object location and identification, and of the visual guidance of locomotion.

  16. iPad Use in Seventh Grade Math: Parent and Student Perceptions

    Science.gov (United States)

    Corbett, Robin

    2015-01-01

    The purpose of this qualitative research study was to compare student and parental perceptions of mobile technology use, specifically iPads, in seventh grade math classrooms and at home. How students and parents perceive the use of iPads within the seventh grade math classroom and how students and parents perceive the influence of iPad use at home…

  17. Neural mechanisms underlying sound-induced visual motion perception: An fMRI study.

    Science.gov (United States)

    Hidaka, Souta; Higuchi, Satomi; Teramoto, Wataru; Sugita, Yoichi

    2017-07-01

    Studies of crossmodal interactions in motion perception have reported activation in several brain areas, including those related to motion processing and/or sensory association, in response to multimodal (e.g., visual and auditory) stimuli that were both in motion. Recent studies have demonstrated that sounds can trigger illusory visual apparent motion to static visual stimuli (sound-induced visual motion: SIVM): A visual stimulus blinking at a fixed location is perceived to be moving laterally when an alternating left-right sound is also present. Here, we investigated brain activity related to the perception of SIVM using a 7T functional magnetic resonance imaging technique. Specifically, we focused on the patterns of neural activities in SIVM and visually induced visual apparent motion (VIVM). We observed shared activations in the middle occipital area (V5/hMT), which is thought to be involved in visual motion processing, for SIVM and VIVM. Moreover, as compared to VIVM, SIVM resulted in greater activation in the superior temporal area and dominant functional connectivity between the V5/hMT area and the areas related to auditory and crossmodal motion processing. These findings indicate that similar but partially different neural mechanisms could be involved in auditory-induced and visually-induced motion perception, and neural signals in auditory, visual, and, crossmodal motion processing areas closely and directly interact in the perception of SIVM. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Do gender differences in audio-visual benefit and visual influence in audio-visual speech perception emerge with age?

    Directory of Open Access Journals (Sweden)

    Magnus eAlm

    2015-07-01

    Full Text Available Gender and age have been found to affect adults’ audio-visual (AV speech perception. However, research on adult aging focuses on adults over 60 years, who have an increasing likelihood for cognitive and sensory decline, which may confound positive effects of age-related AV-experience and its interaction with gender. Observed age and gender differences in AV speech perception may also depend on measurement sensitivity and AV task difficulty. Consequently both AV benefit and visual influence were used to measure visual contribution for gender-balanced groups of young (20-30 years and middle-aged adults (50-60 years with task difficulty varied using AV syllables from different talkers in alternative auditory backgrounds. Females had better speech-reading performance than males. Whereas no gender differences in AV benefit or visual influence were observed for young adults, visually influenced responses were significantly greater for middle-aged females than middle-aged males. That speech-reading performance did not influence AV benefit may be explained by visual speech extraction and AV integration constituting independent abilities. Contrastingly, the gender difference in visually influenced responses in middle adulthood may reflect an experience-related shift in females’ general AV perceptual strategy. Although young females’ speech-reading proficiency may not readily contribute to greater visual influence, between young and middle-adulthood recurrent confirmation of the contribution of visual cues induced by speech-reading proficiency may gradually shift females AV perceptual strategy towards more visually dominated responses.

  19. Visual, Critical, and Scientific Thinking Dispositions in a 3rd Grade Science Classroom

    Science.gov (United States)

    Foss, Stacy

    Many American students leave school without the required 21st century critical thinking skills. This qualitative case study, based on the theoretical concepts of Facione, Arheim, and Vygotsky, explored the development of thinking dispositions through the arts in science on the development of scientific thinking skills when used as a conceptual thinking routine in a rural 3rd grade classroom. Research questions examined the disposition to think critically through the arts in science and focused on the perceptions and experiences of 25 students with the Visual Thinking Strategy (VTS) process. Data were collected from classroom observations (n = 10), student interviews (n = 25), teacher interviews ( n = 1), a focus group discussion (n = 3), and artifacts of student work (n = 25); these data included perceptions of VTS, school culture, and classroom characteristics. An inductive analysis of qualitative data resulted in several emergent themes regarding disposition development and students generating questions while increasing affective motivation. The most prevalent dispositions were open-mindedness, the truth-seeking disposition, the analytical disposition, and the systematicity disposition. The findings about the teachers indicated that VTS questions in science supported "gradual release of responsibility", the internalization of process skills and vocabulary, and argumentation. This case study offers descriptive research that links visual arts inquiry and the development of critical thinking dispositions in science at the elementary level. A science curriculum could be developed, that emphasizes the development of thinking dispositions through the arts in science, which in turn, could impact the professional development of teachers and learning outcomes for students.

  20. A framework for the first-person internal sensation of visual perception in mammals and a comparable circuitry for olfactory perception in Drosophila.

    Science.gov (United States)

    Vadakkan, Kunjumon I

    2015-01-01

    Perception is a first-person internal sensation induced within the nervous system at the time of arrival of sensory stimuli from objects in the environment. Lack of access to the first-person properties has limited viewing perception as an emergent property and it is currently being studied using third-person observed findings from various levels. One feasible approach to understand its mechanism is to build a hypothesis for the specific conditions and required circuit features of the nodal points where the mechanistic operation of perception take place for one type of sensation in one species and to verify it for the presence of comparable circuit properties for perceiving a different sensation in a different species. The present work explains visual perception in mammalian nervous system from a first-person frame of reference and provides explanations for the homogeneity of perception of visual stimuli above flicker fusion frequency, the perception of objects at locations different from their actual position, the smooth pursuit and saccadic eye movements, the perception of object borders, and perception of pressure phosphenes. Using results from temporal resolution studies and the known details of visual cortical circuitry, explanations are provided for (a) the perception of rapidly changing visual stimuli, (b) how the perception of objects occurs in the correct orientation even though, according to the third-person view, activity from the visual stimulus reaches the cortices in an inverted manner and (c) the functional significance of well-conserved columnar organization of the visual cortex. A comparable circuitry detected in a different nervous system in a remote species-the olfactory circuitry of the fruit fly Drosophila melanogaster-provides an opportunity to explore circuit functions using genetic manipulations, which, along with high-resolution microscopic techniques and lipid membrane interaction studies, will be able to verify the structure

  1. The effect of phasic auditory alerting on visual perception

    DEFF Research Database (Denmark)

    Petersen, Anders; Petersen, Annemarie Hilkjær; Bundesen, Claus

    2017-01-01

    /no-alerting design with a pure accuracy-based single-letter recognition task. Computational modeling based on Bundesen’s Theory of Visual Attention was used to examine the effect of phasic alertness on visual processing speed and threshold of conscious perception. Results show that phasic auditory alertness affects...

  2. A Study on the Visualization Skills of 6th Grade Students

    Science.gov (United States)

    Özkan, Ayten; Arikan, Elif Esra; Özkan, Erdogan Mehmet

    2018-01-01

    Visualization is an effective method for students to internalize concepts and to establish correlations between concepts. Visualization method is especially more important in mathematics which is perceived as the combination of abstract concepts. In this study, whether 6th grade students can solve questions about "Fractions" by using…

  3. Opposite Distortions in Interval Timing Perception for Visual and Auditory Stimuli with Temporal Modulations.

    Science.gov (United States)

    Yuasa, Kenichi; Yotsumoto, Yuko

    2015-01-01

    When an object is presented visually and moves or flickers, the perception of its duration tends to be overestimated. Such an overestimation is called time dilation. Perceived time can also be distorted when a stimulus is presented aurally as an auditory flutter, but the mechanisms and their relationship to visual processing remains unclear. In the present study, we measured interval timing perception while modulating the temporal characteristics of visual and auditory stimuli, and investigated whether the interval times of visually and aurally presented objects shared a common mechanism. In these experiments, participants compared the durations of flickering or fluttering stimuli to standard stimuli, which were presented continuously. Perceived durations for auditory flutters were underestimated, while perceived durations of visual flickers were overestimated. When auditory flutters and visual flickers were presented simultaneously, these distortion effects were cancelled out. When auditory flutters were presented with a constantly presented visual stimulus, the interval timing perception of the visual stimulus was affected by the auditory flutters. These results indicate that interval timing perception is governed by independent mechanisms for visual and auditory processing, and that there are some interactions between the two processing systems.

  4. Visual perception of fatigued lifting actions.

    Science.gov (United States)

    Fischer, Steven L; Albert, Wayne J; McGarry, Tim

    2012-12-01

    Fatigue-related changes in lifting kinematics may expose workers to undue injury risks. Early detection of accumulating fatigue offers the prospect of intervention strategies to mitigate such fatigue-related risks. In a first step towards this objective, this study investigated whether fatigue detection was accessible to visual perception and, if so, what was the key visual information required for successful fatigue discrimination. Eighteen participants were tasked with identifying fatigued lifts when viewing 24 trials presented using both video and point-light representations. Each trial comprised a pair of lifting actions containing a fresh and a fatigued lift from the same individual presented in counter-balanced sequence. Confidence intervals demonstrated that the frequency of correct responses for both sexes exceeded chance expectations (50%) for both video (68%±12%) and point-light representations (67%±10%), demonstrating that fatigued lifting kinematics are open to visual perception. There were no significant differences between sexes or viewing condition, the latter result indicating kinematic dynamics as providing sufficient information for successful fatigue discrimination. Moreover, results from single viewer investigation reported fatigue detection (75%) from point-light information describing only the kinematics of the box lifted. These preliminary findings may have important workplace applications if fatigue discrimination rates can be improved upon through future research. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. A Dynamic Systems Theory Model of Visual Perception Development

    Science.gov (United States)

    Coté, Carol A.

    2015-01-01

    This article presents a model for understanding the development of visual perception from a dynamic systems theory perspective. It contrasts to a hierarchical or reductionist model that is often found in the occupational therapy literature. In this proposed model vision and ocular motor abilities are not foundational to perception, they are seen…

  6. Maintenance Procedures for North American Visually-graded Dimension Lumber Design Values

    Science.gov (United States)

    David Kretschmann; Don DeVisser; Kevin Cheung; Bob Browder; Al Rozek

    2014-01-01

    ASTM International D1990 Standard Practice for Establishing Allowable Properties for Visually-Graded Dimension Lumber from In-Grade Tests of Full-Size Specimens, that governs the development of design values for dimension lumber in North America, was first adopted in 1991with recognition that the resource and manufacturing of lumber could change over time impacting...

  7. Neural pathways for visual speech perception

    Directory of Open Access Journals (Sweden)

    Lynne E Bernstein

    2014-12-01

    Full Text Available This paper examines the questions, what levels of speech can be perceived visually, and how is visual speech represented by the brain? Review of the literature leads to the conclusions that every level of psycholinguistic speech structure (i.e., phonetic features, phonemes, syllables, words, and prosody can be perceived visually, although individuals differ in their abilities to do so; and that there are visual modality-specific representations of speech qua speech in higher-level vision brain areas. That is, the visual system represents the modal patterns of visual speech. The suggestion that the auditory speech pathway receives and represents visual speech is examined in light of neuroimaging evidence on the auditory speech pathways. We outline the generally agreed-upon organization of the visual ventral and dorsal pathways and examine several types of visual processing that might be related to speech through those pathways, specifically, face and body, orthography, and sign language processing. In this context, we examine the visual speech processing literature, which reveals widespread diverse patterns activity in posterior temporal cortices in response to visual speech stimuli. We outline a model of the visual and auditory speech pathways and make several suggestions: (1 The visual perception of speech relies on visual pathway representations of speech qua speech. (2 A proposed site of these representations, the temporal visual speech area (TVSA has been demonstrated in posterior temporal cortex, ventral and posterior to multisensory posterior superior temporal sulcus (pSTS. (3 Given that visual speech has dynamic and configural features, its representations in feedforward visual pathways are expected to integrate these features, possibly in TVSA.

  8. Working memory can enhance unconscious visual perception.

    Science.gov (United States)

    Pan, Yi; Cheng, Qiu-Ping; Luo, Qian-Ying

    2012-06-01

    We demonstrate that unconscious processing of a stimulus property can be enhanced when there is a match between the contents of working memory and the stimulus presented in the visual field. Participants first held a cue (a colored circle) in working memory and then searched for a brief masked target shape presented simultaneously with a distractor shape. When participants reported having no awareness of the target shape at all, search performance was more accurate in the valid condition, where the target matched the cue in color, than in the neutral condition, where the target mismatched the cue. This effect cannot be attributed to bottom-up perceptual priming from the presentation of a memory cue, because unconscious perception was not enhanced when the cue was merely perceptually identified but not actively held in working memory. These findings suggest that reentrant feedback from the contents of working memory modulates unconscious visual perception.

  9. Visual Representations of DNA Replication: Middle Grades Students' Perceptions and Interpretations

    Science.gov (United States)

    Patrick, Michelle D.; Carter, Glenda; Wiebe, Eric N.

    2005-01-01

    Visual representations play a critical role in the communication of science concepts for scientists and students alike. However, recent research suggests that novice students experience difficulty extracting relevant information from representations. This study examined students' interpretations of visual representations of DNA replication. Each…

  10. A No Reference Image Quality Assessment Metric Based on Visual Perception

    Directory of Open Access Journals (Sweden)

    Yan Fu

    2016-12-01

    Full Text Available Nowadays, how to evaluate image quality reasonably is a basic and challenging problem. In view of the present no reference evaluation methods, they cannot reflect the human visual perception of image quality accurately. In this paper, we propose an efficient general-purpose no reference image quality assessment (NRIQA method based on visual perception, and effectively integrates human visual characteristics into the NRIQA fields. First, a novel algorithm for salient region extraction is presented. Two characteristics graphs of texture and edging of the original image are added to the Itti model. Due to the normalized luminance coefficients of natural images obey the generalized Gauss probability distribution, we utilize this characteristic to extract statistical features in the regions of interest (ROI and regions of non-interest respectively. Then, the extracted features are fused to be an input to establish the support vector regression (SVR model. Finally, the IQA model obtained by training is used to predict the quality of the image. Experimental results show that this method has good predictive ability, and the evaluation effect is better than existing classical algorithms. Moreover, the predicted results are more consistent with human subjective perception, which can accurately reflect the human visual perception to image quality.

  11. An fMRI study of the neural correlates of graded visual perception

    DEFF Research Database (Denmark)

    Christensen, Mark Schram; Ramsoy, T.Z.; Lund, T.E.

    2006-01-01

    of activation. Different degrees of perceptual clarity were reflected both in the degree to which activation was found within parts of the network serving a clear conscious percept, and additional unique activation patterns for different degrees of perceptual clarity. Our findings support theories proposing...... the involvement of a widespread network of brain areas during conscious perception....

  12. Graded Neuronal Modulations Related to Visual Spatial Attention

    Science.gov (United States)

    Maunsell, John H. R.

    2016-01-01

    Studies of visual attention in monkeys typically measure neuronal activity when the stimulus event to be detected occurs at a cued location versus when it occurs at an uncued location. But this approach does not address how neuronal activity changes relative to conditions where attention is unconstrained by cueing. Human psychophysical studies have used neutral cueing conditions and found that neutrally cued behavioral performance is generally intermediate to that of cued and uncued conditions (Posner et al., 1978; Mangun and Hillyard, 1990; Montagna et al., 2009). To determine whether the neuronal correlates of visual attention during neutral cueing are similarly intermediate, we trained macaque monkeys to detect changes in stimulus orientation that were more likely to occur at one location (cued) than another (uncued), or were equally likely to occur at either stimulus location (neutral). Consistent with human studies, performance was best when the location was cued, intermediate when both locations were neutrally cued, and worst when the location was uncued. Neuronal modulations in visual area V4 were also graded as a function of cue validity and behavioral performance. By recording from both hemispheres simultaneously, we investigated the possibility of switching attention between stimulus locations during neutral cueing. The results failed to support a unitary “spotlight” of attention. Overall, our findings indicate that attention-related changes in V4 are graded to accommodate task demands. SIGNIFICANCE STATEMENT Studies of the neuronal correlates of attention in monkeys typically use visual cues to manipulate where attention is focused (“cued” vs “uncued”). Human psychophysical studies often also include neutrally cued trials to study how attention naturally varies between points of interest. But the neuronal correlates of this neutral condition are unclear. We measured behavioral performance and neuronal activity in cued, uncued, and neutrally

  13. Graded Neuronal Modulations Related to Visual Spatial Attention.

    Science.gov (United States)

    Mayo, J Patrick; Maunsell, John H R

    2016-05-11

    Studies of visual attention in monkeys typically measure neuronal activity when the stimulus event to be detected occurs at a cued location versus when it occurs at an uncued location. But this approach does not address how neuronal activity changes relative to conditions where attention is unconstrained by cueing. Human psychophysical studies have used neutral cueing conditions and found that neutrally cued behavioral performance is generally intermediate to that of cued and uncued conditions (Posner et al., 1978; Mangun and Hillyard, 1990; Montagna et al., 2009). To determine whether the neuronal correlates of visual attention during neutral cueing are similarly intermediate, we trained macaque monkeys to detect changes in stimulus orientation that were more likely to occur at one location (cued) than another (uncued), or were equally likely to occur at either stimulus location (neutral). Consistent with human studies, performance was best when the location was cued, intermediate when both locations were neutrally cued, and worst when the location was uncued. Neuronal modulations in visual area V4 were also graded as a function of cue validity and behavioral performance. By recording from both hemispheres simultaneously, we investigated the possibility of switching attention between stimulus locations during neutral cueing. The results failed to support a unitary "spotlight" of attention. Overall, our findings indicate that attention-related changes in V4 are graded to accommodate task demands. Studies of the neuronal correlates of attention in monkeys typically use visual cues to manipulate where attention is focused ("cued" vs "uncued"). Human psychophysical studies often also include neutrally cued trials to study how attention naturally varies between points of interest. But the neuronal correlates of this neutral condition are unclear. We measured behavioral performance and neuronal activity in cued, uncued, and neutrally cued blocks of trials. Behavioral

  14. Varieties of cognitive penetration in visual perception.

    Science.gov (United States)

    Vetter, Petra; Newen, Albert

    2014-07-01

    Is our perceptual experience a veridical representation of the world or is it a product of our beliefs and past experiences? Cognitive penetration describes the influence of higher level cognitive factors on perceptual experience and has been a debated topic in philosophy of mind and cognitive science. Here, we focus on visual perception, particularly early vision, and how it is affected by contextual expectations and memorized cognitive contents. We argue for cognitive penetration based on recent empirical evidence demonstrating contextual and top-down influences on early visual processes. On the basis of a perceptual model, we propose different types of cognitive penetration depending on the processing level on which the penetration happens and depending on where the penetrating influence comes from. Our proposal has two consequences: (1) the traditional controversy on whether cognitive penetration occurs or not is ill posed, and (2) a clear-cut perception-cognition boundary cannot be maintained. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. The Perceptual Root of Object-Based Storage: An Interactive Model of Perception and Visual Working Memory

    Science.gov (United States)

    Gao, Tao; Gao, Zaifeng; Li, Jie; Sun, Zhongqiang; Shen, Mowei

    2011-01-01

    Mainstream theories of visual perception assume that visual working memory (VWM) is critical for integrating online perceptual information and constructing coherent visual experiences in changing environments. Given the dynamic interaction between online perception and VWM, we propose that how visual information is processed during visual…

  16. Cross-cultural differences in visual perception

    Directory of Open Access Journals (Sweden)

    Jiří Čeněk

    2015-09-01

    Full Text Available According to recent cross-cultural studies there exist culturally based differences between visual perception and the related cognitive processes (attention, memory. According to current research, East Asians and Westerners percieve and think about the world in very different ways. Westerners are inclined to attend to some focal object (a salient object within a perception field that is relatively big in size, fast moving, colourful focusing on and analyzing its attributes. East Asians on the other hand are more likely to attend to a broad perceptual field, noticing relationships and changes. In this paper we want to describe the recent findings in the field and propose some directions for future research.

  17. Aesthetic Perception of Visual Textures: A Holistic Exploration using Texture Analysis, Psychological Experiment and Perception Modeling

    Directory of Open Access Journals (Sweden)

    Jianli eLiu

    2015-11-01

    Full Text Available Modeling human aesthetic perception of visual textures is important and valuable in numerous industrial domains, such as product design, architectural design and decoration. Based on results from a semantic differential rating experiment, we modeled the relationship between low-level basic texture features and aesthetic properties involved in human aesthetic texture perception. First, we compute basic texture features from textural images using four classical methods. These features are neutral, objective and independent of the socio-cultural context of the visual textures. Then, we conduct a semantic differential rating experiment to collect from evaluators their aesthetic perceptions of selected textural stimuli. In semantic differential rating experiment, eights pairs of aesthetic properties are chosen, which are strongly related to the socio-cultural context of the selected textures and to human emotions. They are easily understood and connected to everyday life. We propose a hierarchical feed-forward layer model of aesthetic texture perception and assign 8 pairs of aesthetic properties to different layers. Finally, we describe the generation of multiple linear and nonlinear regression models for aesthetic prediction by taking dimensionality-reduced texture features and aesthetic properties of visual textures as dependent and independent variables, respectively. Our experimental results indicate that the relationships between each layer and its neighbors in the hierarchical feed-forward layer model of aesthetic texture perception can be fitted well by linear functions, and the models thus generated can successfully bridge the gap between computational texture features and aesthetic texture properties.

  18. Depth perception: cuttlefish (Sepia officinalis) respond to visual texture density gradients.

    Science.gov (United States)

    Josef, Noam; Mann, Ofri; Sykes, António V; Fiorito, Graziano; Reis, João; Maccusker, Steven; Shashar, Nadav

    2014-11-01

    Studies concerning the perceptual processes of animals are not only interesting, but are fundamental to the understanding of other developments in information processing among non-humans. Carefully used visual illusions have been proven to be an informative tool for understanding visual perception. In this behavioral study, we demonstrate that cuttlefish are responsive to visual cues involving texture gradients. Specifically, 12 out of 14 animals avoided swimming over a solid surface with a gradient picture that to humans resembles an illusionary crevasse, while only 5 out of 14 avoided a non-illusionary texture. Since texture gradients are well-known cues for depth perception in vertebrates, we suggest that these cephalopods were responding to the depth illusion created by the texture density gradient. Density gradients and relative densities are key features in distance perception in vertebrates. Our results suggest that they are fundamental features of vision in general, appearing also in cephalopods.

  19. Perceptual geometry of space and form: visual perception of natural scenes and their virtual representation

    Science.gov (United States)

    Assadi, Amir H.

    2001-11-01

    Perceptual geometry is an emerging field of interdisciplinary research whose objectives focus on study of geometry from the perspective of visual perception, and in turn, apply such geometric findings to the ecological study of vision. Perceptual geometry attempts to answer fundamental questions in perception of form and representation of space through synthesis of cognitive and biological theories of visual perception with geometric theories of the physical world. Perception of form and space are among fundamental problems in vision science. In recent cognitive and computational models of human perception, natural scenes are used systematically as preferred visual stimuli. Among key problems in perception of form and space, we have examined perception of geometry of natural surfaces and curves, e.g. as in the observer's environment. Besides a systematic mathematical foundation for a remarkably general framework, the advantages of the Gestalt theory of natural surfaces include a concrete computational approach to simulate or recreate images whose geometric invariants and quantities might be perceived and estimated by an observer. The latter is at the very foundation of understanding the nature of perception of space and form, and the (computer graphics) problem of rendering scenes to visually invoke virtual presence.

  20. Language and Visual Perception Associations: Meta-Analytic Connectivity Modeling of Brodmann Area 37

    Directory of Open Access Journals (Sweden)

    Alfredo Ardila

    2015-01-01

    Full Text Available Background. Understanding the functions of different brain areas has represented a major endeavor of neurosciences. Historically, brain functions have been associated with specific cortical brain areas; however, modern neuroimaging developments suggest cognitive functions are associated to networks rather than to areas. Objectives. The purpose of this paper was to analyze the connectivity of Brodmann area (BA 37 (posterior, inferior, and temporal/fusiform gyrus in relation to (1 language and (2 visual processing. Methods. Two meta-analyses were initially conducted (first level analysis. The first one was intended to assess the language network in which BA37 is involved. The second one was intended to assess the visual perception network. A third meta-analysis (second level analysis was then performed to assess contrasts and convergence between the two cognitive domains (language and visual perception. The DataBase of Brainmap was used. Results. Our results support the role of BA37 in language but by means of a distinct network from the network that supports its second most important function: visual perception. Conclusion. It was concluded that left BA37 is a common node of two distinct networks—visual recognition (perception and semantic language functions.

  1. Language and visual perception associations: meta-analytic connectivity modeling of Brodmann area 37.

    Science.gov (United States)

    Ardila, Alfredo; Bernal, Byron; Rosselli, Monica

    2015-01-01

    Understanding the functions of different brain areas has represented a major endeavor of neurosciences. Historically, brain functions have been associated with specific cortical brain areas; however, modern neuroimaging developments suggest cognitive functions are associated to networks rather than to areas. The purpose of this paper was to analyze the connectivity of Brodmann area (BA) 37 (posterior, inferior, and temporal/fusiform gyrus) in relation to (1) language and (2) visual processing. Two meta-analyses were initially conducted (first level analysis). The first one was intended to assess the language network in which BA37 is involved. The second one was intended to assess the visual perception network. A third meta-analysis (second level analysis) was then performed to assess contrasts and convergence between the two cognitive domains (language and visual perception). The DataBase of Brainmap was used. Our results support the role of BA37 in language but by means of a distinct network from the network that supports its second most important function: visual perception. It was concluded that left BA37 is a common node of two distinct networks-visual recognition (perception) and semantic language functions.

  2. Students’ perception of frequent assessments and its relation to motivation and grades in a statistics course: a pilot study

    NARCIS (Netherlands)

    Vaessen, B.E.; van den Beemt, A.A.J.; van de Watering, G.A.; van Meeuwen, L.W.; Lemmens, A.M.C.; den Brok, P.J.

    2017-01-01

    This pilot study measures university students’ perceptions of graded frequent assessments in an obligatory statistics course using a novel questionnaire. Relations between perceptions of frequent assessments, intrinsic motivation and grades were also investigated. A factor analysis of the

  3. Visual perception and frontal lobe in intellectual disabilities: a study with evoked potentials and neuropsychology.

    Science.gov (United States)

    Muñoz-Ruata, J; Caro-Martínez, E; Martínez Pérez, L; Borja, M

    2010-12-01

    Perception disorders are frequently observed in persons with intellectual disability (ID) and their influence on cognition has been discussed. The objective of this study is to clarify the mechanisms behind these alterations by analysing the visual event related potentials early component, the N1 wave, which is related to perception alterations in several pathologies. Additionally, the relationship between N1 and neuropsychological visual tests was studied with the aim to understand its functional significance in ID persons. A group of 69 subjects, with etiologically heterogeneous mild ID, performed an odd-ball task of active discrimination of geometric figures. N1a (frontal) and N1b (post-occipital) waves were obtained from the evoked potentials. They also performed several neuropsychological tests. Only component N1a, produced by the target stimulus, showed significant correlations with the visual integration, visual semantic association, visual analogical reasoning tests, Perceptual Reasoning Index (Wechsler Intelligence Scale for Children Fourth Edition) and intelligence quotient. The systematic correlations, produced by the target stimulus in perceptual abilities tasks, with the N1a (frontal) and not with N1b (posterior), suggest that the visual perception process involves frontal participation. These correlations support the idea that the N1a and N1b are not equivalent. The relationship between frontal functions and early stages of visual perception is revised and discussed, as well as the frontal contribution with the neuropsychological tests used. A possible relationship between the frontal activity dysfunction in ID and perceptive problems is suggested. Perceptive alteration observed in persons with ID could indeed be because of altered sensory areas, but also to a failure in the frontal participation of perceptive processes conceived as elaborations inside reverberant circuits of perception-action. © 2010 The Authors. Journal of Intellectual Disability

  4. Tactile and visual perception of injection moulded plastic parts

    DEFF Research Database (Denmark)

    Jensen, Jacob Tobias; Akbas, Erkan; Madsen, Mads

    In today’s world the technical development have reached high levels in many products. This means that the technical specifications are not as high a competition factor as it has been. Therefore the visual appeal (aesthetics) and tactile perception (ergonomics) have become much more important in t...... in a number of ways including measuring of surface roughness, contact angle, gloss measurement and human perception....

  5. The hippocampus and visual perception

    Science.gov (United States)

    Lee, Andy C. H.; Yeung, Lok-Kin; Barense, Morgan D.

    2012-01-01

    In this review, we will discuss the idea that the hippocampus may be involved in both memory and perception, contrary to theories that posit functional and neuroanatomical segregation of these processes. This suggestion is based on a number of recent neuropsychological and functional neuroimaging studies that have demonstrated that the hippocampus is involved in the visual discrimination of complex spatial scene stimuli. We argue that these findings cannot be explained by long-term memory or working memory processing or, in the case of patient findings, dysfunction beyond the medial temporal lobe (MTL). Instead, these studies point toward a role for the hippocampus in higher-order spatial perception. We suggest that the hippocampus processes complex conjunctions of spatial features, and that it may be more appropriate to consider the representations for which this structure is critical, rather than the cognitive processes that it mediates. PMID:22529794

  6. The hippocampus and visual perception

    Directory of Open Access Journals (Sweden)

    Andy C. H. Lee

    2012-04-01

    Full Text Available In this review, we will discuss the idea that the hippocampus may be involved in both memory and perception, contrary to theories that posit functional and neuroanatomical segregation of these processes. This suggestion is based on a number of recent neuropsychological and functional neuroimaging studies that have demonstrated that the hippocampus is involved in the visual discrimination of complex spatial scene stimuli. We argue that these findings cannot be explained by long-term memory or working memory processing or, in the case of patient findings, dysfunction beyond the medial temporal lobe. Instead, these studies point towards a role for the hippocampus in higher-order spatial perception. We suggest that the hippocampus processes complex conjunctions of spatial features, and that it may be more appropriate to consider the representations for which this structure is critical, rather than the cognitive processes that it mediates.

  7. Memory reactivation improves visual perception.

    Science.gov (United States)

    Amar-Halpert, Rotem; Laor-Maayany, Rony; Nemni, Shlomi; Rosenblatt, Jonathan D; Censor, Nitzan

    2017-10-01

    Human perception thresholds can improve through learning. Here we report findings challenging the fundamental 'practice makes perfect' basis of procedural learning theory, showing that brief reactivations of encoded visual memories are sufficient to improve perceptual discrimination thresholds. Learning was comparable to standard practice-induced learning and was not due to short training per se, nor to an epiphenomenon of primed retrieval enhancement. The results demonstrate that basic perceptual functions can be substantially improved by memory reactivation, supporting a new account of perceptual learning dynamics.

  8. Visual perception and verbal descriptions as sources for generating mental representations: Evidence from representational neglect.

    Science.gov (United States)

    Denis, Michel; Beschin, Nicoletta; Logie, Robert H; Della Sala, Sergio

    2002-03-01

    In the majority of investigations of representational neglect, patients are asked to report information derived from long-term visual knowledge. In contrast, studies of perceptual neglect involve reporting the contents of relatively novel scenes in the immediate environment. The present study aimed to establish how representational neglect might affect (a) immediate recall of recently perceived, novel visual layouts, and (b) immediate recall of novel layouts presented only as auditory verbal descriptions. These conditions were contrasted with reports from visual perception and a test of immediate recall of verbal material. Data were obtained from 11 neglect patients (9 with representational neglect), 6 right hemisphere lesion control patients with no evidence of neglect, and 15 healthy controls. In the perception, memory following perception, and memory following layout description conditions, the neglect patients showed poorer report of items depicted or described on the left than on the right of each layout. The lateralised error pattern was not evident in the non-neglect patients or healthy controls, and there was no difference among the three groups on immediate verbal memory. One patient showed pure representational neglect, with ceiling performance in the perception condition, but with lateralised errors for memory following perception or following verbal description. Overall, the results indicate that representational neglect does not depend on the presence of perceptual neglect, that visual perception and visual mental representations are less closely linked than has been thought hitherto, and that visuospatial mental representations have similar functional characteristics whether they are derived from visual perception or from auditory linguistic descriptive inputs.

  9. Genre Differences on Visual Perception of Color Range and Depth of Field

    Directory of Open Access Journals (Sweden)

    Luisa Ballesteros

    2003-07-01

    Full Text Available Visual perception is the result of the integration of various related factors of the observed object and its environment. In this study we evaluated the impact of tridimensional form on color perception and the angle from the horizontal plane of a set of similar objets on the depth of field perception between young men and women. A panel half magenta and half white placed at the end of a black box, folded either concaved or convexed to alter the chromatic effect perceived were used to determine tridimensional form on color perception. Four sets of identical sticks where the angle from the horizontal plane varied for each, were used to determine the effect of spatial distribution of depth of field perception. The parameters taking into account were age, genre, associated visual defects for each individual evaluated. Our results show that the tridimensional form alters color perception but the range of color perceived was larger for women whereas depending on the angle from the horizontal plane we found genre differences on the depth of field perception.

  10. Visual Form Perception Can Be a Cognitive Correlate of Lower Level Math Categories for Teenagers

    Science.gov (United States)

    Cui, Jiaxin; Zhang, Yiyun; Cheng, Dazhi; Li, Dawei; Zhou, Xinlin

    2017-01-01

    Numerous studies have assessed the cognitive correlates of performance in mathematics, but little research has been conducted to systematically examine the relations between visual perception as the starting point of visuospatial processing and typical mathematical performance. In the current study, we recruited 223 seventh graders to perform a visual form perception task (figure matching), numerosity comparison, digit comparison, exact computation, approximate computation, and curriculum-based mathematical achievement tests. Results showed that, after controlling for gender, age, and five general cognitive processes (choice reaction time, visual tracing, mental rotation, spatial working memory, and non-verbal matrices reasoning), visual form perception had unique contributions to numerosity comparison, digit comparison, and exact computation, but had no significant relation with approximate computation or curriculum-based mathematical achievement. These results suggest that visual form perception is an important independent cognitive correlate of lower level math categories, including the approximate number system, digit comparison, and exact computation. PMID:28824513

  11. A Fundamental Study on Influence of Concurrently Presented Visual Stimulus Upon Loudness Perception

    Directory of Open Access Journals (Sweden)

    Koji Abe

    2011-10-01

    Full Text Available As a basic study on the influence of the dynamic properties of the audio-visual stimuli upon interaction between audition and vision, the effect of the simple movement involved in the visual stimulus on the loudness perception of the audio stimulus was investigated via psychophysical experiment. In this experiment, the visual stimulus given to subjects along with the audio stimulus is a bar appeared on a display, one side of which is flexibly expanding and contracting. The loudness of the audio stimulus with such a visual effect concurrently presented was rated as an absolute numerical value by using the Magnitude Estimation method. The reference of the bar length is determined so as to correspond to the Zwicker's loudness calculated for the given audio stimulus. As a result, the visual stimulus did not affect the loudness perception, when the bar was presented with its length same as the reference. On the other hand, the rating of the loudness for the same audio stimulus was significantly increased when the bar length was longer than the reference. This indicates that the change in the correspondence between the audio and the visual stimuli affect the loudness perception.

  12. Compensatory shifts in visual perception are associated with hallucinations in Lewy body disorders.

    Science.gov (United States)

    Bowman, Alan Robert; Bruce, Vicki; Colbourn, Christopher J; Collerton, Daniel

    2017-01-01

    Visual hallucinations are a common, distressing, and disabling symptom of Lewy body and other diseases. Current models suggest that interactions in internal cognitive processes generate hallucinations. However, these neglect external factors. Pareidolic illusions are an experimental analogue of hallucinations. They are easily induced in Lewy body disease, have similar content to spontaneous hallucinations, and respond to cholinesterase inhibitors in the same way. We used a primed pareidolia task with hallucinating participants with Lewy body disorders (n = 16), non-hallucinating participants with Lewy body disorders (n = 19), and healthy controls (n = 20). Participants were presented with visual "noise" that sometimes contained degraded visual objects and were required to indicate what they saw. Some perceptions were cued in advance by a visual prime. Results showed that hallucinating participants were impaired in discerning visual signals from noise, with a relaxed criterion threshold for perception compared to both other groups. After the presentation of a visual prime, the criterion was comparable to the other groups. The results suggest that participants with hallucinations compensate for perceptual deficits by relaxing perceptual criteria, at a cost of seeing things that are not there, and that visual cues regularize perception. This latter finding may provide a mechanism for understanding the interaction between environments and hallucinations.

  13. A systematic review of the technology-based assessment of visual perception and exploration behaviour in association football.

    Science.gov (United States)

    McGuckian, Thomas B; Cole, Michael H; Pepping, Gert-Jan

    2018-04-01

    To visually perceive opportunities for action, athletes rely on the movements of their eyes, head and body to explore their surrounding environment. To date, the specific types of technology and their efficacy for assessing the exploration behaviours of association footballers have not been systematically reviewed. This review aimed to synthesise the visual perception and exploration behaviours of footballers according to the task constraints, action requirements of the experimental task, and level of expertise of the athlete, in the context of the technology used to quantify the visual perception and exploration behaviours of footballers. A systematic search for papers that included keywords related to football, technology, and visual perception was conducted. All 38 included articles utilised eye-movement registration technology to quantify visual perception and exploration behaviour. The experimental domain appears to influence the visual perception behaviour of footballers, however no studies investigated exploration behaviours of footballers in open-play situations. Studies rarely utilised representative stimulus presentation or action requirements. To fully understand the visual perception requirements of athletes, it is recommended that future research seek to validate alternate technologies that are capable of investigating the eye, head and body movements associated with the exploration behaviours of footballers during representative open-play situations.

  14. Correlated individual differences suggest a common mechanism underlying metacognition in visual perception and visual short-term memory.

    Science.gov (United States)

    Samaha, Jason; Postle, Bradley R

    2017-11-29

    Adaptive behaviour depends on the ability to introspect accurately about one's own performance. Whether this metacognitive ability is supported by the same mechanisms across different tasks is unclear. We investigated the relationship between metacognition of visual perception and metacognition of visual short-term memory (VSTM). Experiments 1 and 2 required subjects to estimate the perceived or remembered orientation of a grating stimulus and rate their confidence. We observed strong positive correlations between individual differences in metacognitive accuracy between the two tasks. This relationship was not accounted for by individual differences in task performance or average confidence, and was present across two different metrics of metacognition and in both experiments. A model-based analysis of data from a third experiment showed that a cross-domain correlation only emerged when both tasks shared the same task-relevant stimulus feature. That is, metacognition for perception and VSTM were correlated when both tasks required orientation judgements, but not when the perceptual task was switched to require contrast judgements. In contrast with previous results comparing perception and long-term memory, which have largely provided evidence for domain-specific metacognitive processes, the current findings suggest that metacognition of visual perception and VSTM is supported by a domain-general metacognitive architecture, but only when both domains share the same task-relevant stimulus feature. © 2017 The Author(s).

  15. Perception of audio-visual speech synchrony in Spanish-speaking children with and without specific language impairment.

    Science.gov (United States)

    Pons, Ferran; Andreu, Llorenç; Sanz-Torrent, Monica; Buil-Legaz, Lucía; Lewkowicz, David J

    2013-06-01

    Speech perception involves the integration of auditory and visual articulatory information, and thus requires the perception of temporal synchrony between this information. There is evidence that children with specific language impairment (SLI) have difficulty with auditory speech perception but it is not known if this is also true for the integration of auditory and visual speech. Twenty Spanish-speaking children with SLI, twenty typically developing age-matched Spanish-speaking children, and twenty Spanish-speaking children matched for MLU-w participated in an eye-tracking study to investigate the perception of audiovisual speech synchrony. Results revealed that children with typical language development perceived an audiovisual asynchrony of 666 ms regardless of whether the auditory or visual speech attribute led the other one. Children with SLI only detected the 666 ms asynchrony when the auditory component preceded [corrected] the visual component. None of the groups perceived an audiovisual asynchrony of 366 ms. These results suggest that the difficulty of speech processing by children with SLI would also involve difficulties in integrating auditory and visual aspects of speech perception.

  16. Hemispheric asymmetry in the influence of language on visual perception.

    Science.gov (United States)

    Sun, Yanliang; Cai, Yongchun; Lu, Shena

    2015-07-01

    Many studies have shown that language can affect visual perception; however, our understanding of the neural basis of linguistic influence is inadequate. This can be investigated by examining the hemispheric asymmetry of linguistic influence. The left and right hemispheres are dominant in close and distant semantic processing, respectively. In this study, we investigated whether the hemispheric asymmetry of semantic processing led to hemispheric asymmetry for concept priming on the detection of objects degraded by continuous flash suppression. We combined a priming paradigm with the divided visual field paradigm and used continuous flash suppression, which renders objects invisible. The results indicated that the hemispheric asymmetry of semantic processing led to a right lateralization in the influence of more abstract concepts on visual perception. The lateralization of brain connectomes may be the underlying neural basis of this effect. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Influence of Visual Motion, Suggestion, and Illusory Motion on Self-Motion Perception in the Horizontal Plane.

    Science.gov (United States)

    Rosenblatt, Steven David; Crane, Benjamin Thomas

    2015-01-01

    A moving visual field can induce the feeling of self-motion or vection. Illusory motion from static repeated asymmetric patterns creates a compelling visual motion stimulus, but it is unclear if such illusory motion can induce a feeling of self-motion or alter self-motion perception. In these experiments, human subjects reported the perceived direction of self-motion for sway translation and yaw rotation at the end of a period of viewing set visual stimuli coordinated with varying inertial stimuli. This tested the hypothesis that illusory visual motion would influence self-motion perception in the horizontal plane. Trials were arranged into 5 blocks based on stimulus type: moving star field with yaw rotation, moving star field with sway translation, illusory motion with yaw, illusory motion with sway, and static arrows with sway. Static arrows were used to evaluate the effect of cognitive suggestion on self-motion perception. Each trial had a control condition; the illusory motion controls were altered versions of the experimental image, which removed the illusory motion effect. For the moving visual stimulus, controls were carried out in a dark room. With the arrow visual stimulus, controls were a gray screen. In blocks containing a visual stimulus there was an 8s viewing interval with the inertial stimulus occurring over the final 1s. This allowed measurement of the visual illusion perception using objective methods. When no visual stimulus was present, only the 1s motion stimulus was presented. Eight women and five men (mean age 37) participated. To assess for a shift in self-motion perception, the effect of each visual stimulus on the self-motion stimulus (cm/s) at which subjects were equally likely to report motion in either direction was measured. Significant effects were seen for moving star fields for both translation (p = 0.001) and rotation (pperception was shifted in the direction consistent with the visual stimulus. Arrows had a small effect on self

  18. The use of sensory perception indicators for improving the characterization and modelling of total petroleum hydrocarbon (TPH) grade in soils.

    Science.gov (United States)

    Roxo, Sónia; de Almeida, José António; Matias, Filipa Vieira; Mata-Lima, Herlander; Barbosa, Sofia

    2016-03-01

    This paper proposes a multistep approach for creating a 3D stochastic model of total petroleum hydrocarbon (TPH) grade in potentially polluted soils of a deactivated oil storage site by using chemical analysis results as primary or hard data and classes of sensory perception variables as secondary or soft data. First, the statistical relationship between the sensory perception variables (e.g. colour, odour and oil-water reaction) and TPH grade is analysed, after which the sensory perception variable exhibiting the highest correlation is selected (oil-water reaction in this case study). The probabilities of cells belonging to classes of oil-water reaction are then estimated for the entire soil volume using indicator kriging. Next, local histograms of TPH grade for each grid cell are computed, combining the probabilities of belonging to a specific sensory perception indicator class and conditional to the simulated values of TPH grade. Finally, simulated images of TPH grade are generated by using the P-field simulation algorithm, utilising the local histograms of TPH grade for each grid cell. The set of simulated TPH values allows several calculations to be performed, such as average values, local uncertainties and the probability of the TPH grade of the soil exceeding a specific threshold value.

  19. Visual application of the American Board of Orthodontics Grading System.

    Science.gov (United States)

    Scott, Steven A; Freer, Terry J

    2005-05-01

    Assessment of treatment outcomes has traditionally been accomplished using the subjective opinion of experienced clinicians. Reduced subjectivity in the assessment of orthodontic treatment can be achieved with the use of an occlusal index. To implement an index for quality assurance purposes is time-consuming and subject to the inherent error of the index. Quality assessment of orthodontic treatment on a routine basis has been difficult to implement in private practice. To investigate whether a clinician can accurately apply the American Board of Orthodontics Objective Grading System by direct visual inspection instead of measuring individual traits. A random sample of 30 cases was selected, including pretreatment and post-treatment upper and lower study casts and panoramic radiographs. The cases were examined and scored with the standardized measuring gauge according to the protocol provided by the American Board of Orthodontics (ABO). The records were re-examined 6 weeks later and the individual traits scored by visual inspection (VI). There were no significant differences between the pre- and post-treatment ABO gauge and VI scores. This study suggests that occlusal traits defined by the ABO Objective Grading System can be accurately assessed by visual inspection. The VI score provides a simple and convenient method for critical evaluation of treatment outcome by a clinician.

  20. Parents' Perceptions of Physical Activity for Their Children with Visual Impairments

    Science.gov (United States)

    Perkins, Kara; Columna, Luis; Lieberman, Lauren; Bailey, JoEllen

    2013-01-01

    Introduction: Ongoing communication with parents and the acknowledgment of their preferences and expectations are crucial to promote the participation of physical activity by children with visual impairments. Purpose: The study presented here explored parents' perceptions of physical activity for their children with visual impairments and explored…

  1. Laws of visual perception and their consequences for the user interface

    NARCIS (Netherlands)

    Nes, van F.L.; Brouwer-Janse, M.D.; Harrington, T.L.

    1994-01-01

    Knowledge of visual perception is needed to display text and graphics in an effective and efficient way. This paper therefore describes the visual processes involved in reading and the effects of typography. spatiallayout and text colours on legibility. Some information is given on graphics, as an

  2. Benefit of spatial filtering for visual perception with a subretinal implant.

    Science.gov (United States)

    Rieger, Viola; Aryan, Naser Pour; Brendler, Christian; Rothermel, Albrecht

    2014-01-01

    Subretinal implants have proven to be capable of restoring vision to patients suffering from hereditary retinal degeneration diseases like retinitis pigmentosa and cone-rod dystrophy. Although they already provide basic visual perception, there is still much room for improvement in this field. Effects like electric field interference limit the visual acuity and may be the cause of the perceived vision to be blurred. This influence could be reduced by means of highpass spatial filtering. In this paper, based on the available reports about the visual perception parameters from the patients using the alpha-IMS subretinal implant, a model for the blurring effect of the patients retina is proposed. On this basis, highpass filters are suggested which will compensate the obscuring effect of the stimulator device plus retina system to some extent.

  3. African American eighth-grade female students' perceptions and experiences as learners of science literacy

    Science.gov (United States)

    Crim, Sharan R.

    The National Assessment of Educational Progress (2000) reports an achievement gap between male and female students and majority and minority students in science literacy. Rutherford and Algren (2000) describe a scientifically literate person as one who is aware that science, mathematics, and technology are interdependent human enterprises with strengths and limitations; understands key concepts and principles of science; is familiar with the natural world and recognizes both its diversity and unity; and uses scientific knowledge and scientific ways of thinking for individual and social purposes. The purpose of this qualitative case study research was to investigate African American eighth grade female students' perceptions and experiences as learners of science literacy. A social learning theory (Bandura, 1986) and constructivist theory (Vygotsky, 1977) served as a guide for the researcher. Two questions were explored: (1) What are African American eighth grade female students' perceptions and experiences as learners of science literacy? (2) In what ways do the perceptions and experiences of African American eighth grade female students influence their learning of science literacy? Purposeful sampling (Merriam, 1998) was used with four African American eighth grade female students selected as participants for the study. Data collection and analysis occurred between February and August in a single year. Data sources included an open-ended questionnaire, two in-depth interviews with each participant (Seidman, 1991); classroom observations, participant reflective journals, student artifacts, and a researcher's log. Data were analyzed through the constant comparative method (Glaser & Strauss, 1967), and richly descriptive participant portraits and qualitative case studies (Merriam, 1998) were used to report the findings. Three themes emerged from the study that positively affected the perceptions and experiences of African American eighth grade female students as

  4. Spatial Frequency Requirements and Gaze Strategy in Visual-Only and Audiovisual Speech Perception

    Science.gov (United States)

    Wilson, Amanda H.; Alsius, Agnès; Parè, Martin; Munhall, Kevin G.

    2016-01-01

    Purpose: The aim of this article is to examine the effects of visual image degradation on performance and gaze behavior in audiovisual and visual-only speech perception tasks. Method: We presented vowel-consonant-vowel utterances visually filtered at a range of frequencies in visual-only, audiovisual congruent, and audiovisual incongruent…

  5. Visual perception can account for the close relation between numerosity processing and computational fluency.

    Science.gov (United States)

    Zhou, Xinlin; Wei, Wei; Zhang, Yiyun; Cui, Jiaxin; Chen, Chuansheng

    2015-01-01

    Studies have shown that numerosity processing (e.g., comparison of numbers of dots in two dot arrays) is significantly correlated with arithmetic performance. Researchers have attributed this association to the fact that both tasks share magnitude processing. The current investigation tested an alternative hypothesis, which states that visual perceptual ability (as measured by a figure-matching task) can account for the close relation between numerosity processing and arithmetic performance (computational fluency). Four hundred and twenty four third- to fifth-grade children (220 boys and 204 girls, 8.0-11.0 years old; 120 third graders, 146 fourth graders, and 158 fifth graders) were recruited from two schools (one urban and one suburban) in Beijing, China. Six classes were randomly selected from each school, and all students in each selected class participated in the study. All children were given a series of cognitive and mathematical tests, including numerosity comparison, figure matching, forward verbal working memory, visual tracing, non-verbal matrices reasoning, mental rotation, choice reaction time, arithmetic tests and curriculum-based mathematical achievement test. Results showed that figure-matching ability had higher correlations with numerosity processing and computational fluency than did other cognitive factors (e.g., forward verbal working memory, visual tracing, non-verbal matrix reasoning, mental rotation, and choice reaction time). More important, hierarchical multiple regression showed that figure matching ability accounted for the well-established association between numerosity processing and computational fluency. In support of the visual perception hypothesis, the results suggest that visual perceptual ability, rather than magnitude processing, may be the shared component of numerosity processing and arithmetic performance.

  6. Teachers' Perceptions of Developmentally Appropriate Practices in Teaching Reading and Writing for First Grade Students in Kuwait

    Science.gov (United States)

    Al-Dhafir, Mohammad

    2015-01-01

    The purpose of the study was to examine the Kuwaiti first grade teachers' perceptions of developmentally appropriate practices in teaching reading and writing. To achieve the research purpose, a questionnaire was developed and administrated to 167 first grade teachers. Results revealed that first grade teachers hold moderate agreement towards…

  7. Behind Mathematical Learning Disabilities: What about Visual Perception and Motor Skills?

    Science.gov (United States)

    Pieters, Stefanie; Desoete, Annemie; Roeyers, Herbert; Vanderswalmen, Ruth; Van Waelvelde, Hilde

    2012-01-01

    In a sample of 39 children with mathematical learning disabilities (MLD) and 106 typically developing controls belonging to three control groups of three different ages, we found that visual perception, motor skills and visual-motor integration explained a substantial proportion of the variance in either number fact retrieval or procedural…

  8. Audio-Visual Speech Perception: A Developmental ERP Investigation

    Science.gov (United States)

    Knowland, Victoria C. P.; Mercure, Evelyne; Karmiloff-Smith, Annette; Dick, Fred; Thomas, Michael S. C.

    2014-01-01

    Being able to see a talking face confers a considerable advantage for speech perception in adulthood. However, behavioural data currently suggest that children fail to make full use of these available visual speech cues until age 8 or 9. This is particularly surprising given the potential utility of multiple informational cues during language…

  9. How do visual and postural cues combine for self-tilt perception during slow pitch rotations?

    Science.gov (United States)

    Scotto Di Cesare, C; Buloup, F; Mestre, D R; Bringoux, L

    2014-11-01

    Self-orientation perception relies on the integration of multiple sensory inputs which convey spatially-related visual and postural cues. In the present study, an experimental set-up was used to tilt the body and/or the visual scene to investigate how these postural and visual cues are integrated for self-tilt perception (the subjective sensation of being tilted). Participants were required to repeatedly rate a confidence level for self-tilt perception during slow (0.05°·s(-1)) body and/or visual scene pitch tilts up to 19° relative to vertical. Concurrently, subjects also had to perform arm reaching movements toward a body-fixed target at certain specific angles of tilt. While performance of a concurrent motor task did not influence the main perceptual task, self-tilt detection did vary according to the visuo-postural stimuli. Slow forward or backward tilts of the visual scene alone did not induce a marked sensation of self-tilt contrary to actual body tilt. However, combined body and visual scene tilt influenced self-tilt perception more strongly, although this effect was dependent on the direction of visual scene tilt: only a forward visual scene tilt combined with a forward body tilt facilitated self-tilt detection. In such a case, visual scene tilt did not seem to induce vection but rather may have produced a deviation of the perceived orientation of the longitudinal body axis in the forward direction, which may have lowered the self-tilt detection threshold during actual forward body tilt. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Human cortical neural correlates of visual fatigue during binocular depth perception: An fNIRS study.

    Directory of Open Access Journals (Sweden)

    Tingting Cai

    Full Text Available Functional near-infrared spectroscopy (fNIRS was adopted to investigate the cortical neural correlates of visual fatigue during binocular depth perception for different disparities (from 0.1° to 1.5°. By using a slow event-related paradigm, the oxyhaemoglobin (HbO responses to fused binocular stimuli presented by the random-dot stereogram (RDS were recorded over the whole visual dorsal area. To extract from an HbO curve the characteristics that are correlated with subjective experiences of stereopsis and visual fatigue, we proposed a novel method to fit the time-course HbO curve with various response functions which could reflect various processes of binocular depth perception. Our results indicate that the parietal-occipital cortices are spatially correlated with binocular depth perception and that the process of depth perception includes two steps, associated with generating and sustaining stereovision. Visual fatigue is caused mainly by generating stereovision, while the amplitude of the haemodynamic response corresponding to sustaining stereovision is correlated with stereopsis. Combining statistical parameter analysis and the fitted time-course analysis, fNIRS could be a promising method to study visual fatigue and possibly other multi-process neural bases.

  11. Crossmodal Semantic Constraints on Visual Perception of Binocular Rivalry

    Directory of Open Access Journals (Sweden)

    Yi-Chuan Chen

    2011-10-01

    Full Text Available Environments typically convey contextual information via several different sensory modalities. Here, we report a study designed to investigate the crossmodal semantic modulation of visual perception using the binocular rivalry paradigm. The participants viewed a dichoptic figure consisting of a bird and a car presented to each eye, while also listening to either a bird singing or car engine revving. Participants' dominant percepts were modulated by the presentation of a soundtrack associated with either bird or car, as compared to the presentation of a soundtrack irrelevant to both visual figures (tableware clattering together in a restaurant. No such crossmodal semantic effect was observed when the participants maintained an abstract semantic cue in memory. We then further demonstrate that crossmodal semantic modulation can be dissociated from the effects of high-level attentional control over the dichoptic figures and of low-level luminance contrast of the figures. In sum, we demonstrate a novel crossmodal effect in terms of crossmodal semantic congruency on binocular rivalry. This effect can be considered a perceptual grouping or contextual constraint on human visual awareness through mid-level crossmodal excitatory connections embedded in the multisensory semantic network.

  12. Statistical regularities in art: Relations with visual coding and perception.

    Science.gov (United States)

    Graham, Daniel J; Redies, Christoph

    2010-07-21

    Since at least 1935, vision researchers have used art stimuli to test human response to complex scenes. This is sensible given the "inherent interestingness" of art and its relation to the natural visual world. The use of art stimuli has remained popular, especially in eye tracking studies. Moreover, stimuli in common use by vision scientists are inspired by the work of famous artists (e.g., Mondrians). Artworks are also popular in vision science as illustrations of a host of visual phenomena, such as depth cues and surface properties. However, until recently, there has been scant consideration of the spatial, luminance, and color statistics of artwork, and even less study of ways that regularities in such statistics could affect visual processing. Furthermore, the relationship between regularities in art images and those in natural scenes has received little or no attention. In the past few years, there has been a concerted effort to study statistical regularities in art as they relate to neural coding and visual perception, and art stimuli have begun to be studied in rigorous ways, as natural scenes have been. In this minireview, we summarize quantitative studies of links between regular statistics in artwork and processing in the visual stream. The results of these studies suggest that art is especially germane to understanding human visual coding and perception, and it therefore warrants wider study. Copyright 2010 Elsevier Ltd. All rights reserved.

  13. The effect of combined sensory and semantic components on audio-visual speech perception in older adults

    Directory of Open Access Journals (Sweden)

    Corrina eMaguinness

    2011-12-01

    Full Text Available Previous studies have found that perception in older people benefits from multisensory over uni-sensory information. As normal speech recognition is affected by both the auditory input and the visual lip-movements of the speaker, we investigated the efficiency of audio and visual integration in an older population by manipulating the relative reliability of the auditory and visual information in speech. We also investigated the role of the semantic context of the sentence to assess whether audio-visual integration is affected by top-down semantic processing. We presented participants with audio-visual sentences in which the visual component was either blurred or not blurred. We found that there was a greater cost in recall performance for semantically meaningless speech in the audio-visual blur compared to audio-visual no blur condition and this effect was specific to the older group. Our findings have implications for understanding how aging affects efficient multisensory integration for the perception of speech and suggests that multisensory inputs may benefit speech perception in older adults when the semantic content of the speech is unpredictable.

  14. Shape perception simultaneously up- and downregulates neural activity in the primary visual cortex.

    Science.gov (United States)

    Kok, Peter; de Lange, Floris P

    2014-07-07

    An essential part of visual perception is the grouping of local elements (such as edges and lines) into coherent shapes. Previous studies have shown that this grouping process modulates neural activity in the primary visual cortex (V1) that is signaling the local elements [1-4]. However, the nature of this modulation is controversial. Some studies find that shape perception reduces neural activity in V1 [2, 5, 6], while others report increased V1 activity during shape perception [1, 3, 4, 7-10]. Neurocomputational theories that cast perception as a generative process [11-13] propose that feedback connections carry predictions (i.e., the generative model), while feedforward connections signal the mismatch between top-down predictions and bottom-up inputs. Within this framework, the effect of feedback on early visual cortex may be either enhancing or suppressive, depending on whether the feedback signal is met by congruent bottom-up input. Here, we tested this hypothesis by quantifying the spatial profile of neural activity in V1 during the perception of illusory shapes using population receptive field mapping. We find that shape perception concurrently increases neural activity in regions of V1 that have a receptive field on the shape but do not receive bottom-up input and suppresses activity in regions of V1 that receive bottom-up input that is predicted by the shape. These effects were not modulated by task requirements. Together, these findings suggest that shape perception changes lower-order sensory representations in a highly specific and automatic manner, in line with theories that cast perception in terms of hierarchical generative models. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Visual space perception at different levels of depth description

    Czech Academy of Sciences Publication Activity Database

    Šikl, Radovan; Šimeček, Michal

    2015-01-01

    Roč. 77, č. 6 (2015), 2098–2107 ISSN 1943-3921 R&D Projects: GA ČR GA13-28709S Institutional support: RVO:68081740 Keywords : visual space perception * Depth scales * Level of description Subject RIV: AN - Psychology Impact factor: 1.782, year: 2015

  16. Perceptual Training Strongly Improves Visual Motion Perception in Schizophrenia

    Science.gov (United States)

    Norton, Daniel J.; McBain, Ryan K.; Ongur, Dost; Chen, Yue

    2011-01-01

    Schizophrenia patients exhibit perceptual and cognitive deficits, including in visual motion processing. Given that cognitive systems depend upon perceptual inputs, improving patients' perceptual abilities may be an effective means of cognitive intervention. In healthy people, motion perception can be enhanced through perceptual learning, but it…

  17. Using Pupillometry to Characterize Visual Perception in Autistic Mouse Models

    OpenAIRE

    Patel, Chirag B; Kissinger, Samuel T; Pak, Alexandr; DiCola, Nicholas; Chubkyin, Alexander A

    2016-01-01

    Fragile X syndrome (FXS) is the leading genetic cause of autism. Individuals with Fragile X Syndrome (FXS) commonly display social, behavioral, and intellectual disabilities. Perceptual deficits and their underlying neural activity remain poorly characterized in FXS and other autism spectrum disorders (ASD’s). To explore visual perception in autism, we developed camera based pupil tracking software using OpenCV (an open-source computer vision library) capable of measuring visually evoked chan...

  18. Visualizing the Perception Filter and Breaching It with Active-Learning Strategies

    Science.gov (United States)

    White, Harold B.

    2012-01-01

    Teachers' perception filter operates in all realms of their consciousness. It plays an important part in what and how students learn and should play a central role in what and how they teach. This may be obvious, but having a visual model of a perception filter can guide the way they think about education. In this article, the author talks about…

  19. Influence of Visual Motion, Suggestion, and Illusory Motion on Self-Motion Perception in the Horizontal Plane.

    Directory of Open Access Journals (Sweden)

    Steven David Rosenblatt

    Full Text Available A moving visual field can induce the feeling of self-motion or vection. Illusory motion from static repeated asymmetric patterns creates a compelling visual motion stimulus, but it is unclear if such illusory motion can induce a feeling of self-motion or alter self-motion perception. In these experiments, human subjects reported the perceived direction of self-motion for sway translation and yaw rotation at the end of a period of viewing set visual stimuli coordinated with varying inertial stimuli. This tested the hypothesis that illusory visual motion would influence self-motion perception in the horizontal plane. Trials were arranged into 5 blocks based on stimulus type: moving star field with yaw rotation, moving star field with sway translation, illusory motion with yaw, illusory motion with sway, and static arrows with sway. Static arrows were used to evaluate the effect of cognitive suggestion on self-motion perception. Each trial had a control condition; the illusory motion controls were altered versions of the experimental image, which removed the illusory motion effect. For the moving visual stimulus, controls were carried out in a dark room. With the arrow visual stimulus, controls were a gray screen. In blocks containing a visual stimulus there was an 8s viewing interval with the inertial stimulus occurring over the final 1s. This allowed measurement of the visual illusion perception using objective methods. When no visual stimulus was present, only the 1s motion stimulus was presented. Eight women and five men (mean age 37 participated. To assess for a shift in self-motion perception, the effect of each visual stimulus on the self-motion stimulus (cm/s at which subjects were equally likely to report motion in either direction was measured. Significant effects were seen for moving star fields for both translation (p = 0.001 and rotation (p0.1 for both. Thus, although a true moving visual field can induce self-motion, results of this

  20. Turbidity in oil-in-water-emulsions - Key factors and visual perception.

    Science.gov (United States)

    Linke, C; Drusch, S

    2016-11-01

    The aim of the present study is to systematically describe the factors affecting turbidity in beverage emulsions and to get a better understanding of visual perception of turbidity. The sensory evaluation of the human visual perception of turbidity showed that humans are most sensitive to turbidity differences between two samples in the range between 1000 and 1500 NTU (ratio) (nephelometric turbidity units). At very high turbidity values >2000 TU in NTU (ratio) were needed to distinguish between samples that they were perceived significantly different. Particle size was the most important factor affecting turbidity. It was shown that a maximum turbidity occurs at a mean volume - surface diameter of 0.2μm for the oil droplet size. Additional parameters were the refractive index, the composition of the aqueous phase and the presence of excess emulsifier. In a concentration typical for a beverage emulsion a change in the refractive index of the oil phase may allow the alteration of turbidity by up to 30%. With the knowledge on visual perception of turbidity and the determining factors, turbidity can be tailored in product development according to the customer requirements and in quality control to define acceptable variations in optical appearance. Copyright © 2016. Published by Elsevier Ltd.

  1. United we sense, divided we fail: context-driven perception of ambiguous visual stimuli.

    NARCIS (Netherlands)

    Klink, P.C.; van Wezel, R.J.A.; van Ee, R.

    2012-01-01

    Ambiguous visual stimuli provide the brain with sensory information that contains conflicting evidence for multiple mutually exclusive interpretations. Two distinct aspects of the phenomenological experience associated with viewing ambiguous visual stimuli are the apparent stability of perception

  2. United we sense, divided we fail: context-driven perception of ambiguous visual stimuli

    NARCIS (Netherlands)

    Klink, P. C; van Wezel, Richard Jack Anton; van Ee, R.

    2012-01-01

    Ambiguous visual stimuli provide the brain with sensory information that contains conflicting evidence for multiple mutually exclusive interpretations. Two distinct aspects of the phenomenological experience associated with viewing ambiguous visual stimuli are the apparent stability of perception

  3. Visuality and reading. Psychological and perceptive dynamics of reading environments (from the printed page to the visual hypertext

    Directory of Open Access Journals (Sweden)

    Micla Petrelli

    2013-02-01

    Full Text Available This essay investigates the psychological and perceptive view of reading as a visual fact and looks at its operations in different environments: from the traditional printed page to the more recent electronic page of the e-book, with particular attention reserved to the relationship between "word" (the linguistic aspects covered by the alphabetical vision and "image" (image of the word and image with the word - visual hypertext integrated with verbal texts in e-book. In the light of the studies of the Psychology of perception, Neurophysiology and Phenomenology, the experience of reading is a function that transcends those value systems tending to oppose the categories of verbal and visual, intellect and intuition, logos and disorder. But literature shows even better the inviolability of belonging of word and image, and how the thinking in images consists in building a bridge between the visible trace and the invisible thing.

  4. High-Resolution Remotely Sensed Small Target Detection by Imitating Fly Visual Perception Mechanism

    Directory of Open Access Journals (Sweden)

    Fengchen Huang

    2012-01-01

    Full Text Available The difficulty and limitation of small target detection methods for high-resolution remote sensing data have been a recent research hot spot. Inspired by the information capture and processing theory of fly visual system, this paper endeavors to construct a characterized model of information perception and make use of the advantages of fast and accurate small target detection under complex varied nature environment. The proposed model forms a theoretical basis of small target detection for high-resolution remote sensing data. After the comparison of prevailing simulation mechanism behind fly visual systems, we propose a fly-imitated visual system method of information processing for high-resolution remote sensing data. A small target detector and corresponding detection algorithm are designed by simulating the mechanism of information acquisition, compression, and fusion of fly visual system and the function of pool cell and the character of nonlinear self-adaption. Experiments verify the feasibility and rationality of the proposed small target detection model and fly-imitated visual perception method.

  5. High-resolution remotely sensed small target detection by imitating fly visual perception mechanism.

    Science.gov (United States)

    Huang, Fengchen; Xu, Lizhong; Li, Min; Tang, Min

    2012-01-01

    The difficulty and limitation of small target detection methods for high-resolution remote sensing data have been a recent research hot spot. Inspired by the information capture and processing theory of fly visual system, this paper endeavors to construct a characterized model of information perception and make use of the advantages of fast and accurate small target detection under complex varied nature environment. The proposed model forms a theoretical basis of small target detection for high-resolution remote sensing data. After the comparison of prevailing simulation mechanism behind fly visual systems, we propose a fly-imitated visual system method of information processing for high-resolution remote sensing data. A small target detector and corresponding detection algorithm are designed by simulating the mechanism of information acquisition, compression, and fusion of fly visual system and the function of pool cell and the character of nonlinear self-adaption. Experiments verify the feasibility and rationality of the proposed small target detection model and fly-imitated visual perception method.

  6. Determination of distances to visible points of bodies in a system of visual perception

    Energy Technology Data Exchange (ETDEWEB)

    Nevskiy, I V; Osadchiy, S M; Solntsev, S V

    1981-09-01

    An examination is made of problems connected with the determination of the form of bodies in a system of visual perception. The effect of parallax, which is familiar from the psychology of vision, is basic for the construction of a model of a system of visual perception. An estimate of the error of discrete realization of the relationships obtained in solution of the problems is also made. A model experiment is described. 12 references.

  7. Evaluation of a visual risk communication tool: effects on knowledge and perception of blood transfusion risk.

    Science.gov (United States)

    Lee, D H; Mehta, M D

    2003-06-01

    Effective risk communication in transfusion medicine is important for health-care consumers, but understanding the numerical magnitude of risks can be difficult. The objective of this study was to determine the effect of a visual risk communication tool on the knowledge and perception of transfusion risk. Laypeople were randomly assigned to receive transfusion risk information with either a written or a visual presentation format for communicating and comparing the probabilities of transfusion risks relative to other hazards. Knowledge of transfusion risk was ascertained with a multiple-choice quiz and risk perception was ascertained by psychometric scaling and principal components analysis. Two-hundred subjects were recruited and randomly assigned. Risk communication with both written and visual presentation formats increased knowledge of transfusion risk and decreased the perceived dread and severity of transfusion risk. Neither format changed the perceived knowledge and control of transfusion risk, nor the perceived benefit of transfusion. No differences in knowledge or risk perception outcomes were detected between the groups randomly assigned to written or visual presentation formats. Risk communication that incorporates risk comparisons in either written or visual presentation formats can improve knowledge and reduce the perception of transfusion risk in laypeople.

  8. Visual illusion of tool use recalibrates tactile perception

    Science.gov (United States)

    Miller, Luke E.; Longo, Matthew R.; Saygin, Ayse P.

    2018-01-01

    Brief use of a tool recalibrates multisensory representations of the user’s body, a phenomenon called tool embodiment. Despite two decades of research, little is known about its boundary conditions. It has been widely argued that embodiment requires active tool use, suggesting a critical role for somatosensory and motor feedback. The present study used a visual illusion to cast doubt on this view. We used a mirror-based setup to induce a visual experience of tool use with an arm that was in fact stationary. Following illusory tool use, tactile perception was recalibrated on this stationary arm, and with equal magnitude as physical use. Recalibration was not found following illusory passive tool holding, and could not be accounted for by sensory conflict or general interhemispheric plasticity. These results suggest visual tool-use signals play a critical role in driving tool embodiment. PMID:28196765

  9. Category Selectivity of Human Visual Cortex in Perception of Rubin Face–Vase Illusion

    Directory of Open Access Journals (Sweden)

    Xiaogang Wang

    2017-09-01

    Full Text Available When viewing the Rubin face–vase illusion, our conscious perception spontaneously alternates between the face and the vase; this illusion has been widely used to explore bistable perception. Previous functional magnetic resonance imaging (fMRI studies have studied the neural mechanisms underlying bistable perception through univariate and multivariate pattern analyses; however, no studies have investigated the issue of category selectivity. Here, we used fMRI to investigate the neural mechanisms underlying the Rubin face–vase illusion by introducing univariate amplitude and multivariate pattern analyses. The results from the amplitude analysis suggested that the activity in the fusiform face area was likely related to the subjective face perception. Furthermore, the pattern analysis results showed that the early visual cortex (EVC and the face-selective cortex could discriminate the activity patterns of the face and vase perceptions. However, further analysis of the activity patterns showed that only the face-selective cortex contains the face information. These findings indicated that although the EVC and face-selective cortex activities could discriminate the visual information, only the activity and activity pattern in the face-selective areas contained the category information of face perception in the Rubin face–vase illusion.

  10. Visual Literacy Development through the Mediation of Grade 4 English Textbooks

    Science.gov (United States)

    Sibanda, Jabulani; Sibanda, Lucy

    2013-01-01

    The multimodal world learners inhabit demands visual literacy among other literacies if learners are to effectively navigate its terrain. In this study, we sought to understand the extent to which five Grade 4 English textbooks currently used in some schools in the Eastern Cape province of South Africa facilitated the development of visual…

  11. Attitudes towards and perceptions of visual loss and its causes among Hong Kong Chinese adults.

    Science.gov (United States)

    Lau, Joseph Tak Fai; Lee, Vincent; Fan, Dorothy; Lau, Mason; Michon, John

    2004-06-01

    As part of a study of visual function among Hong Kong Chinese adults, their attitudes and perceptions related to visual loss were examined. These included fear of visual loss, negative functional impacts of visual loss, the relationship between ageing and visual loss and help-seeking behaviours related to visual loss. Demographic factors associated with these variables were also studied. The study population were people aged 40 and above randomly selected from the Shatin district of Hong Kong. The participants underwent eye examinations that included visual acuity, intraocular pressure measurement, visual field, slit-lamp biomicroscopy and ophthalmoscopy. The primary cause of visual disability was recorded. The participants were also asked about their attitudes and perceptions regarding visual loss using a structured questionnaire. The prevalence of bilateral visual disability was 2.2% among adults aged 40 or above and 6.4% among adults aged 60 or above. Nearly 36% of the participants selected blindness as the most feared disabling medical condition, which was substantially higher than conditions such as dementia, loss of limbs, deafness or aphasia. Inability to take care of oneself (21.0%), inconvenience related to mobility (20.2%) and inability to work (14.8%) were the three most commonly mentioned 'worst impact' effects of visual loss. Fully 68% of the participants believed that loss of vision is related to ageing. A majority of participants would seek help and advice from family members in case of visual loss. Visual function is perceived to be very important by Hong Kong Chinese adults. The fear of visual loss is widespread and particularly affects self-care and functional abilities. Visual loss is commonly seen as related to ageing. Attitudes and perceptions in this population may be modified by educational and outreach efforts in order to take advantage of preventive measures.

  12. Visual hallucinations in schizophrenia: confusion between imagination and perception.

    Science.gov (United States)

    Brébion, Gildas; Ohlsen, Ruth I; Pilowsky, Lyn S; David, Anthony S

    2008-05-01

    An association between hallucinations and reality-monitoring deficit has been repeatedly observed in patients with schizophrenia. Most data concern auditory/verbal hallucinations. The aim of this study was to investigate the association between visual hallucinations and a specific type of reality-monitoring deficit, namely confusion between imagined and perceived pictures. Forty-one patients with schizophrenia and 43 healthy control participants completed a reality-monitoring task. Thirty-two items were presented either as written words or as pictures. After the presentation phase, participants had to recognize the target words and pictures among distractors, and then remember their mode of presentation. All groups of participants recognized the pictures better than the words, except the patients with visual hallucinations, who presented the opposite pattern. The participants with visual hallucinations made more misattributions to pictures than did the others, and higher ratings of visual hallucinations were correlated with increased tendency to remember words as pictures. No association with auditory hallucinations was revealed. Our data suggest that visual hallucinations are associated with confusion between visual mental images and perception.

  13. The effect of various grading scales on student grade point averages.

    Science.gov (United States)

    Barnes, Kelli D; Buring, Shauna M

    2012-04-10

    To investigate changes in and the impact of grading scales from 2005 to 2010 and explore pharmacy faculty and student perceptions of whole-letter and plus/minus grading scales on cumulative grade point averages (GPAs) in required courses. Grading scales used in 2010 at the University of Cincinnati College of Pharmacy were retrospectively identified and compared to those used in 2005. Mean GPA was calculated using a whole-letter grading scale and a plus/minus grading scale to determine the impact of scales on GPA. Faculty members and students were surveyed regarding their perceptions of plus/minus grading. Nine unique grading scales were used throughout the curriculum, including plus/minus (64%) and whole-letter (21%) grading scales. From 2005 to 2010 there was transition from use of predominantly whole-letter scales to plus/minus grading scales. The type of grading scale used did not affect the mean cumulative GPA. Students preferred use of a plus-only grading scale while faculty members preferred use of a plus/minus grading scale. The transition from whole-letter grading to plus/minus grading in courses from 2005 to 2010 reflects pharmacy faculty members' perception that plus/minus grading allows for better differentiation between students' performances.

  14. Research on Language of Perception Still-Life as a Visual Aphorism

    Directory of Open Access Journals (Sweden)

    Anatolij P. Suprun

    2011-01-01

    Full Text Available This article describes a categorical structure of perception of still-life painting. Analysis is done on the system of visual opposition elements in still-life. A still-life is considered a "perceptual statement about the world", and a "visual aphorism" The research is based on such methods as: semantic spaces constructing and their transformation at introduction of additional elements in still-lifes. It also gives full analysis of an interpretation of complex images and understanding of types of still-life as a visual hermeneutics.

  15. The influence of auditory and visual information on the perception of crispy food

    NARCIS (Netherlands)

    Pocztaruk, R.D.; Abbink, J.H.; Wijk, de R.A.; Frasca, L.C.D.; Gaviao, M.B.D.; Bilt, van de A.

    2011-01-01

    The influence of auditory and/or visual information on the perception of crispy food and on the physiology of chewing was investigated. Participants chewed biscuits of three different levels of crispness under four experimental conditions: no masking, auditory masking, visual masking, and auditory

  16. Assistive Technology Competencies of Teachers of Students with Visual Impairments: A Comparison of Perceptions

    Science.gov (United States)

    Zhou, Li; Smith, Derrick W.; Parker, Amy T.; Griffin-Shirley, Nora

    2011-01-01

    This study surveyed teachers of students with visual impairments in Texas on their perceptions of a set of assistive technology competencies developed for teachers of students with visual impairments by Smith and colleagues (2009). Differences in opinion between practicing teachers of students with visual impairments and Smith's group of…

  17. Testing the generality of the zoom-lens model: Evidence for visual-pathway specific effects of attended-region size on perception.

    Science.gov (United States)

    Goodhew, Stephanie C; Lawrence, Rebecca K; Edwards, Mark

    2017-05-01

    There are volumes of information available to process in visual scenes. Visual spatial attention is a critically important selection mechanism that prevents these volumes from overwhelming our visual system's limited-capacity processing resources. We were interested in understanding the effect of the size of the attended area on visual perception. The prevailing model of attended-region size across cognition, perception, and neuroscience is the zoom-lens model. This model stipulates that the magnitude of perceptual processing enhancement is inversely related to the size of the attended region, such that a narrow attended-region facilitates greater perceptual enhancement than a wider region. Yet visual processing is subserved by two major visual pathways (magnocellular and parvocellular) that operate with a degree of independence in early visual processing and encode contrasting visual information. Historically, testing of the zoom-lens has used measures of spatial acuity ideally suited to parvocellular processing. This, therefore, raises questions about the generality of the zoom-lens model to different aspects of visual perception. We found that while a narrow attended-region facilitated spatial acuity and the perception of high spatial frequency targets, it had no impact on either temporal acuity or the perception of low spatial frequency targets. This pattern also held up when targets were not presented centrally. This supports the notion that visual attended-region size has dissociable effects on magnocellular versus parvocellular mediated visual processing.

  18. Visual arts and the teaching of the mathematical concepts of shape and space in Grade R classrooms

    Directory of Open Access Journals (Sweden)

    Dianne Wilmot

    2015-09-01

    Full Text Available This article addresses the need for research in the areas of Grade R curriculum and pedagogy, Grade R teacher professional development, and early years mathematics teaching. More specifically, it responds to the need for teacher professional development in Grade R mathematics teaching of the geometric concepts of space and shape. The article describes a study about teachers’ understanding of how visual arts can be used as pedagogical modality. The study was prompted by the findings of a ‘Maths and Science through Arts and Culture Curriculum’ intervention undertaken with Grade R teachers enrolled for a Bachelor of Education (Foundation Phase degree at a South African university. Post-intervention, teachers’ classroom practices did not change, and they were not using visual arts to teach mathematical concepts. The lessons learned from the research intervention may contribute to the wider debate about Grade R teaching and children’s learning.

  19. Within- and cross-modal distance information disambiguate visual size-change perception.

    Directory of Open Access Journals (Sweden)

    Peter W Battaglia

    2010-03-01

    Full Text Available Perception is fundamentally underconstrained because different combinations of object properties can generate the same sensory information. To disambiguate sensory information into estimates of scene properties, our brains incorporate prior knowledge and additional "auxiliary" (i.e., not directly relevant to desired scene property sensory information to constrain perceptual interpretations. For example, knowing the distance to an object helps in perceiving its size. The literature contains few demonstrations of the use of prior knowledge and auxiliary information in combined visual and haptic disambiguation and almost no examination of haptic disambiguation of vision beyond "bistable" stimuli. Previous studies have reported humans integrate multiple unambiguous sensations to perceive single, continuous object properties, like size or position. Here we test whether humans use visual and haptic information, individually and jointly, to disambiguate size from distance. We presented participants with a ball moving in depth with a changing diameter. Because no unambiguous distance information is available under monocular viewing, participants rely on prior assumptions about the ball's distance to disambiguate their -size percept. Presenting auxiliary binocular and/or haptic distance information augments participants' prior distance assumptions and improves their size judgment accuracy-though binocular cues were trusted more than haptic. Our results suggest both visual and haptic distance information disambiguate size perception, and we interpret these results in the context of probabilistic perceptual reasoning.

  20. Research progress of functional magnetic resonance imaging in cross-modal activation of visual cortex during tactile perception

    International Nuclear Information System (INIS)

    Zhan Jie; Gong Honghan

    2013-01-01

    An increasing amount of neuroimaging studies recently demonstrated activation of visual cortex in both blind and sighted participants when performing a variety of tactile tasks such as Braille reading and tactile object recognition, which indicates that visual cortex not only receives visual information, but may participate in tactile perception. To address these cross-modal changes of visual cortex and the neurophysiological mechanisms, many researchers conducted explosive studies using functional magnetic resonance imaging (fMRI) and have made some achievements. This review focuses on cross-modal activation of visual cortex and the underlying mechanisms during tactile perception in both blind and sighted individuals. (authors)

  1. Perception, Cognition, and Effectiveness of Visualizations with Applications in Science and Engineering

    Science.gov (United States)

    Borkin, Michelle A.

    Visualization is a powerful tool for data exploration and analysis. With data ever-increasing in quantity and becoming integrated into our daily lives, having effective visualizations is necessary. But how does one design an effective visualization? To answer this question we need to understand how humans perceive, process, and understand visualizations. Through visualization evaluation studies we can gain deeper insight into the basic perception and cognition theory of visualizations, both through domain-specific case studies as well as generalized laboratory experiments. This dissertation presents the results of four evaluation studies, each of which contributes new knowledge to the theory of perception and cognition of visualizations. The results of these studies include a deeper clearer understanding of how color, data representation dimensionality, spatial layout, and visual complexity affect a visualization's effectiveness, as well as how visualization types and visual attributes affect the memorability of a visualization. We first present the results of two domain-specific case study evaluations. The first study is in the field of biomedicine in which we developed a new heart disease diagnostic tool, and conducted a study to evaluate the effectiveness of 2D versus 3D data representations as well as color maps. In the second study, we developed a new visualization tool for filesystem provenance data with applications in computer science and the sciences more broadly. We additionally developed a new time-based hierarchical node grouping method. We then conducted a study to evaluate the effectiveness of the new tool with its radial layout versus the conventional node-link diagram, and the new node grouping method. Finally, we discuss the results of two generalized studies designed to understand what makes a visualization memorable. In the first evaluation we focused on visualization memorability and conducted an online study using Amazon's Mechanical Turk with

  2. Visual-vestibular cue integration for heading perception: applications of optimal cue integration theory.

    Science.gov (United States)

    Fetsch, Christopher R; Deangelis, Gregory C; Angelaki, Dora E

    2010-05-01

    The perception of self-motion is crucial for navigation, spatial orientation and motor control. In particular, estimation of one's direction of translation, or heading, relies heavily on multisensory integration in most natural situations. Visual and nonvisual (e.g., vestibular) information can be used to judge heading, but each modality alone is often insufficient for accurate performance. It is not surprising, then, that visual and vestibular signals converge frequently in the nervous system, and that these signals interact in powerful ways at the level of behavior and perception. Early behavioral studies of visual-vestibular interactions consisted mainly of descriptive accounts of perceptual illusions and qualitative estimation tasks, often with conflicting results. In contrast, cue integration research in other modalities has benefited from the application of rigorous psychophysical techniques, guided by normative models that rest on the foundation of ideal-observer analysis and Bayesian decision theory. Here we review recent experiments that have attempted to harness these so-called optimal cue integration models for the study of self-motion perception. Some of these studies used nonhuman primate subjects, enabling direct comparisons between behavioral performance and simultaneously recorded neuronal activity. The results indicate that humans and monkeys can integrate visual and vestibular heading cues in a manner consistent with optimal integration theory, and that single neurons in the dorsal medial superior temporal area show striking correlates of the behavioral effects. This line of research and other applications of normative cue combination models should continue to shed light on mechanisms of self-motion perception and the neuronal basis of multisensory integration.

  3. DYNAMICS OF THE COMPELEX FORMS OF VISUAL PERCEPTION IN CHILDREN OF PRE-SCHOOL AGE (A NEUROPSYCHOLOGICAL ANALYSIS)

    OpenAIRE

    VASILEVA Neli

    2015-01-01

    Introduction: Experimental data in preschool aged children proves the determining role of the auditory and visual processes for future reading skills, therefore the investigation of complex forms of visual perception in this age period is diagnostically important. Objectives: Basic aim of the research is assessment of the sensitive period for the non-verbal perceptive operations in pre-school aged children, and determination of subgroup with low results for non-verbal perception. Method...

  4. Effects of auditory information on self-motion perception during simultaneous presentation of visual shearing motion

    Science.gov (United States)

    Tanahashi, Shigehito; Ashihara, Kaoru; Ujike, Hiroyasu

    2015-01-01

    Recent studies have found that self-motion perception induced by simultaneous presentation of visual and auditory motion is facilitated when the directions of visual and auditory motion stimuli are identical. They did not, however, examine possible contributions of auditory motion information for determining direction of self-motion perception. To examine this, a visual stimulus projected on a hemisphere screen and an auditory stimulus presented through headphones were presented separately or simultaneously, depending on experimental conditions. The participant continuously indicated the direction and strength of self-motion during the 130-s experimental trial. When the visual stimulus with a horizontal shearing rotation and the auditory stimulus with a horizontal one-directional rotation were presented simultaneously, the duration and strength of self-motion perceived in the opposite direction of the auditory rotation stimulus were significantly longer and stronger than those perceived in the same direction of the auditory rotation stimulus. However, the auditory stimulus alone could not sufficiently induce self-motion perception, and if it did, its direction was not consistent within each experimental trial. We concluded that auditory motion information can determine perceived direction of self-motion during simultaneous presentation of visual and auditory motion information, at least when visual stimuli moved in opposing directions (around the yaw-axis). We speculate that the contribution of auditory information depends on the plausibility and information balance of visual and auditory information. PMID:26113828

  5. Medical and pharmacy students' perceptions of the grading and assessment practices

    OpenAIRE

    Kasanda, C. D.; Mitonga, K. H.; Veii, K.; Zimba, R. F.

    2013-01-01

    Many students at the University of Namibia have frequently complained about ineffective assessment practices used at the institution. On many occasions, these complaints have not been substantiated with evidence of any kind. The purpose of this study was to obtain some empirical evidence that would ascertain undergraduate students' perceptions of the University of Namibia's grading and assessment practices. Using a structured scaled questionnaire, data were obtained from a representative samp...

  6. Sampling of post-Riley visual artists surreptitiously probing perception

    Science.gov (United States)

    Daly, Scott J.

    2003-06-01

    Attending any conference on visual perception undoubtedly leaves one exposed to the work of Salvador Dali, whose extended phase of work exploring what he dubbed, "the paranoiac-critical method" is very popular as examples of multiple perceptions from conflicting input. While all visual art is intertwined with perceptual science, from convincing three-dimensional illusion during the Renaissance to the isolated visual illusions of Bridget Riley"s Op-Art, direct statements about perception are rarely uttered by the artists in recent times. However, there are still a number of artists working today whose work contains perceptual questions and exemplars that can be of interest to vision scientists and imaging engineers. This talk will start sampling from Op-Art, which is most directly related to psychophysical test stimuli and then will discuss "perceptual installations" from artists such as James Turrell"s, whose focus is often directly on natural light, with no distortions imposed by any capture or display apparatus. His work generally involves installations that use daylight and focus the viewer on its nuanced qualities, such as umbra, air particle interactions, and effects of light adaptation. He is one of the last artists to actively discuss perception. Next we discuss minimal art and electronic art, with video artist Nam June Paik discussing the "intentionally boring" art of minimalism. Another artist using installations is Sandy Skoglund, who creates environments of constant spectral albedo, with the exception of her human occupants. Tom Shannon also uses installations as his media to delve into 3D aspects of depth and perspective, but in an atomized fashion. Beginning with installation concepts, Calvin Collum then adds the restrictive viewpoint of photography to create initially confusing images where the pictorial content and depth features are independent (analogous to the work of Patrick Hughes). Andy Goldsworthy also combines photography with concepts of

  7. N1 enhancement in synesthesia during visual and audio-visual perception in semantic cross-modal conflict situations: an ERP study

    Directory of Open Access Journals (Sweden)

    Christopher eSinke

    2014-01-01

    Full Text Available Synesthesia entails a special kind of sensory perception, where stimulation in one sensory modality leads to an internally generated perceptual experience of another, not stimulated sensory modality. This phenomenon can be viewed as an abnormal multisensory integration process as here the synesthetic percept is aberrantly fused with the stimulated modality. Indeed, recent synesthesia research has focused on multimodal processing even outside of the specific synesthesia-inducing context and has revealed changed multimodal integration, thus suggesting perceptual alterations at a global level. Here, we focused on audio-visual processing in synesthesia using a semantic classification task in combination with visually or auditory-visually presented animated and inanimated objects in an audio-visual congruent and incongruent manner. Fourteen subjects with auditory-visual and/or grapheme-color synesthesia and 14 control subjects participated in the experiment. During presentation of the stimuli, event-related potentials were recorded from 32 electrodes. The analysis of reaction times and error rates revealed no group differences with best performance for audio-visually congruent stimulation indicating the well-known multimodal facilitation effect. We found an enhanced amplitude of the N1 component over occipital electrode sites for synesthetes compared to controls. The differences occurred irrespective of the experimental condition and therefore suggest a global influence on early sensory processing in synesthetes.

  8. The "School Safety & Security Questionnaire": Middle Grades Students' Perceptions of Safety at School

    Science.gov (United States)

    Miller, Janice Williams; Nickell, Linda K.

    2008-01-01

    This study presents the development and basic psychometric characteristics of the "School Safety and Security Questionnaire" (SSSQ). This new measure was constructed to assess middle grade students' perceptions of safety and security during the school year. The content validity of the theoretically-based instrument was assessed and the measure was…

  9. The effect of neurofeedback on a brain wave and visual perception in stroke: a randomized control trial.

    Science.gov (United States)

    Cho, Hwi-Young; Kim, Kitae; Lee, Byounghee; Jung, Jinhwa

    2015-03-01

    [Purpose] This study investigated a brain wave and visual perception changes in stroke subjects using neurofeedback (NFB) training. [Subjects] Twenty-seven stroke subjects were randomly allocated to the NFB (n = 13) group and the control group (n=14). [Methods] Two expert therapists provided the NFB and CON groups with traditional rehabilitation therapy in 30 thirst-minute sessions over the course of 6 weeks. NFB training was provided only to the NFB group. The CON group received traditional rehabilitation therapy only. Before and after the 6-week intervention, a brain wave test and motor free visual perception test (MVPT) were performed. [Results] Both groups showed significant differences in their relative beta wave values and attention concentration quotients. Moreover, the NFB group showed a significant difference in MVPT visual discrimination, form constancy, visual memory, visual closure, spatial relation, raw score, and processing time. [Conclusion] This study demonstrated that NFB training is more effective for increasing concentration and visual perception changes than traditional rehabilitation. In further studies, detailed and diverse investigations should be performed considering the number and characteristics of subjects, and the NFB training period.

  10. Knowledge corruption for visual perception in individuals high on paranoia.

    Science.gov (United States)

    Moritz, Steffen; Göritz, Anja S; Van Quaquebeke, Niels; Andreou, Christina; Jungclaussen, David; Peters, Maarten J V

    2014-03-30

    Studies revealed that patients with paranoid schizophrenia display overconfidence in errors for memory and social cognition tasks. The present investigation examined whether this pattern holds true for visual perception tasks. Nonclinical participants were recruited via an online panel. Individuals were asked to complete a questionnaire that included the Paranoia Checklist and were then presented with 24 blurry pictures; half contained a hidden object while the other half showed snowy (visual) noise. Participants were asked to state whether the visual items contained an object and how confident they were in their judgment. Data from 1966 individuals were included following a conservative selection process. Participants high on core paranoid symptoms showed a poor calibration of confidence for correct versus incorrect responses. In particular, participants high on paranoia displayed overconfidence in incorrect responses and demonstrated a 20% error rate for responses made with high confidence compared to a 12% error rate in participants with low paranoia scores. Interestingly, paranoia scores declined after performance of the task. For the first time, overconfidence in errors was demonstrated among individuals with high levels of paranoia using a visual perception task, tentatively suggesting it is a ubiquitous phenomenon. In view of the significant decline in paranoia across time, bias modification programs may incorporate items such as the one employed here to teach patients with clinical paranoia the fallibility of human cognition, which may foster subsequent symptom improvement. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Dynamic Visual Perception and Reading Development in Chinese School Children

    Science.gov (United States)

    Meng, Xiangzhi; Cheng-Lai, Alice; Zeng, Biao; Stein, John F.; Zhou, Xiaolin

    2011-01-01

    The development of reading skills may depend to a certain extent on the development of basic visual perception. The magnocellular theory of developmental dyslexia assumes that deficits in the magnocellular pathway, indicated by less sensitivity in perceiving dynamic sensory stimuli, are responsible for a proportion of reading difficulties…

  12. VISUAL PERCEPTION OF THE CHILDREN WITH PLEXUS BRACHIALIS DAMAGE – ASSESSMENT AND TREATMENT

    Directory of Open Access Journals (Sweden)

    Dragana M. KLJAJIKJ

    2012-03-01

    Full Text Available Interpersonal communication, psychosocial and mental development of personality and its all other functions take place through the motor control. The most common neurological syndrome is a type of peripheral paresis/paralysis of plexus bracialis, which in most cases occurs at birth and significantly compromises the growth and development of the upper extremities and affects the psychomotor performance. The aim of this study was to evaluate the level of visual perception in children with lesion of plexus brachialis and the effect of the somatopedic treatment over the level of increase of the visual perception. The study sample was consisted of 60 preschool children accommodated at the Rehabilitation Centre “Dr. Miroslav Zotović” in Belgrade (experimental group and examiners that followed regular checkups and had discontinuity in their therapy (control group. For the research purposes, we used The Test for Visual Perception Assessment. By analyzing the results, we concluded that in both, in the first and the second measuring there was a statistically significant correlation between the experimental and the control groups (I measuring: p<0.001, r = 0.408; II measuring: p <0.001, r = 0.593.

  13. Visual perception is dependent on visuospatial working memory and thus on the posterior parietal cortex.

    Science.gov (United States)

    Pisella, Laure

    2017-06-01

    Visual perception involves complex and active processes. We will start by explaining why visual perception is dependent on visuospatial working memory, especially the spatiotemporal integration of the perceived elements through the ocular exploration of visual scenes. Then we will present neuropsychology, transcranial magnetic stimulation and neuroimaging data yielding information on the specific role of the posterior parietal cortex of the right hemisphere in visuospatial working memory. Within the posterior parietal cortex, neuropsychology data also suggest that there might be dissociated neural substrates for deployment of attention (superior parietal lobules) and spatiotemporal integration (right inferior parietal lobule). Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. [Complex visual hallucinations following occipital infarct and perception of optical illusions].

    Science.gov (United States)

    Renou, P; Deltour, S; Samson, Y

    2008-05-01

    The physiopathology of visual hallucinations in the hemianopic field secondary to occipital infarct is uncertain. We report the case of a patient with a history of occipital infarct who presented nonstereotyped complex hallucinations in the quadranopic field resulting from a second controlateral occipital infarct. Based on an experience with motion optical illusions, we suggested that the association of these two occipital lesions, involving the V5 motion area on the one side and the V1 area on the other side, could have produced the complex hallucinations due to a release phenomenon. The patient experienced simultaneously a double visual consciousness, with both hallucinations and real visual perceptions. The study of perceptual illusions in patients with visual hallucinations could illustrate the innovative theory of visual consciousness as being not unified but constituted of multiple microconsciousnesses.

  15. The Relationship between Grade 11 Palestinian Attitudes toward Biology and Their Perceptions of the Biology Learning Environment

    Science.gov (United States)

    Zeidan, Afif

    2010-01-01

    The aims of the study were to investigate (a) the relationship between the attitudes toward biology and perceptions of the biology learning environment among grade 11 students in Tulkarm District, Palestine and (b) the effect of gender and residence of these students on their attitudes toward biology and on their perceptions of the biology…

  16. Visual Timing of Structured Dance Movements Resembles Auditory Rhythm Perception

    Science.gov (United States)

    Su, Yi-Huang; Salazar-López, Elvira

    2016-01-01

    Temporal mechanisms for processing auditory musical rhythms are well established, in which a perceived beat is beneficial for timing purposes. It is yet unknown whether such beat-based timing would also underlie visual perception of temporally structured, ecological stimuli connected to music: dance. In this study, we investigated whether observers extracted a visual beat when watching dance movements to assist visual timing of these movements. Participants watched silent videos of dance sequences and reproduced the movement duration by mental recall. We found better visual timing for limb movements with regular patterns in the trajectories than without, similar to the beat advantage for auditory rhythms. When movements involved both the arms and the legs, the benefit of a visual beat relied only on the latter. The beat-based advantage persisted despite auditory interferences that were temporally incongruent with the visual beat, arguing for the visual nature of these mechanisms. Our results suggest that visual timing principles for dance parallel their auditory counterparts for music, which may be based on common sensorimotor coupling. These processes likely yield multimodal rhythm representations in the scenario of music and dance. PMID:27313900

  17. Biometric Research in Perception and Neurology Related to the Study of Visual Communication.

    Science.gov (United States)

    Metallinos, Nikos

    Contemporary research findings in the fields of perceptual psychology and neurology of the human brain that are directly related to the study of visual communication are reviewed and briefly discussed in this paper. Specifically, the paper identifies those major research findings in visual perception that are relevant to the study of visual…

  18. Visual perception of spatial subjects

    International Nuclear Information System (INIS)

    Osterloh, K.R.S.; Ewert, U.

    2007-01-01

    Principally, any imaging technology consists of two consecutive, though strictly separated processes: data acquisition and subsequent processing to generate an image that can be looked at, either on a monitor screen or printed on paper. Likewise, the physiological process of viewing can be separated into vision and perception, though these processes are much more overlapping. Understanding the appearance of a subject requires the entire sequence from receiving the information carried e.g. by photons up to an appropriate processing leading to the perception of the subject shown. As a consequence, the imagination of a subject is a result of both, technological and physiological processes. Whenever an evaluation of an image is critical, also the physiological part of the processing should be considered. However, an image has two dimensions in the first place and reality is spatial, it has three dimensions. This problem has been tackled on a philosophical level at least since Platon's famous discussion on the shadow image in a dark cave. The mere practical point is which structural details can be perceived and what may remain undetected depending on the mode of presentation. This problem cannot be resolved without considering each single step of visual perception. Physiologically, there are three 'tools' available to understanding the spatial structure of a subject: binocular viewing, following the course of perspective projection and motion to collect multiple aspects. Artificially, an object may be cut in various ways to display the interior or covering parts could be made transparent within a model. Samples will be shown how certain details of a subject can be emphasised or hidden depending on the way of presentation. It needs to be discussed what might help to perceive the true spatial structure of a subject with all relevant details and what could be misleading. (authors)

  19. Visual perception of spatial subjects

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K.R.S.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Berlin (Germany)

    2007-07-01

    Principally, any imaging technology consists of two consecutive, though strictly separated processes: data acquisition and subsequent processing to generate an image that can be looked at, either on a monitor screen or printed on paper. Likewise, the physiological process of viewing can be separated into vision and perception, though these processes are much more overlapping. Understanding the appearance of a subject requires the entire sequence from receiving the information carried e.g. by photons up to an appropriate processing leading to the perception of the subject shown. As a consequence, the imagination of a subject is a result of both, technological and physiological processes. Whenever an evaluation of an image is critical, also the physiological part of the processing should be considered. However, an image has two dimensions in the first place and reality is spatial, it has three dimensions. This problem has been tackled on a philosophical level at least since Platon's famous discussion on the shadow image in a dark cave. The mere practical point is which structural details can be perceived and what may remain undetected depending on the mode of presentation. This problem cannot be resolved without considering each single step of visual perception. Physiologically, there are three 'tools' available to understanding the spatial structure of a subject: binocular viewing, following the course of perspective projection and motion to collect multiple aspects. Artificially, an object may be cut in various ways to display the interior or covering parts could be made transparent within a model. Samples will be shown how certain details of a subject can be emphasised or hidden depending on the way of presentation. It needs to be discussed what might help to perceive the true spatial structure of a subject with all relevant details and what could be misleading. (authors)

  20. Using visual stimuli to explore the social perceptions of ecosystem services in cultural landscapes

    DEFF Research Database (Denmark)

    López-Santiago, César A.; Oteros-Rozas, Elisa; Martín-López, Berta

    2014-01-01

    , which are used for herd migration, represent the most outstanding feature of these landscapes. We used visually based landscape interpretation to evaluate social perceptions of ecosystem services provided by the Conquense Drove Road transhumance landscape in Spain. Face-to-face questionnaires (N = 314...... perceptions of 16 ecosystem services supplied by these two landscapes. These 16 services were divided into 3 types: provisioning, such as the production of food and water; regulating, such as the control of climate and disease; and cultural, such as spiritual and recreational benefits. We also identified...... ecosystem services tended to be related to forests. All three types of ecosystem services were more perceived by respondents when a drove road was present in each landscape. However, differences in the visual perception of ecosystem services supply and preference for transhumance landscapes emerged...

  1. Use of subjective and objective criteria to categorise visual disability.

    Science.gov (United States)

    Kajla, Garima; Rohatgi, Jolly; Dhaliwal, Upreet

    2014-04-01

    Visual disability is categorised using objective criteria. Subjective measures are not considered. To use subjective criteria along with objective ones to categorise visual disability. Ophthalmology out-patient department; teaching hospital; observational study. Consecutive persons aged >25 years, with vision disability; group-zero: normal range of vision, to group-X: no perception of light, bilaterally. Snellen's vision; binocular contrast sensitivity (Pelli-Robson chart); automated binocular visual field (Humphrey; Esterman test); and vision-related quality of life (Indian Visual Function Questionnaire-33; IND-VFQ33) were recorded. SPSS version-17; Kruskal-wallis test was used to compare contrast sensitivity and visual fields across groups, and Mann-Whitney U test for pair-wise comparison (Bonferroni adjustment; P visual fields were comparable for differing disability grades except when disability was severe (P disability grades but comparable for groups III (78.51 ± 6.86) and IV (82.64 ± 5.80), and groups IV and V (77.23 ± 3.22); these were merged to generate group 345; similarly, global scores were comparable for adjacent groups V and VI (72.53 ± 6.77), VI and VII (74.46 ± 4.32), and VII and VIII (69.12 ± 5.97); these were merged to generate group 5678; thereafter, contrast sensitivity and global and individual IND-VFQ33 scores could differentiate between different grades of disability in the five new groups. Subjective criteria made it possible to objectively reclassify visual disability. Visual disability grades could be redefined to accommodate all from zero-100%.

  2. DYNAMICS OF THE COMPELEX FORMS OF VISUAL PERCEPTION IN CHILDREN OF PRE-SCHOOL AGE (A NEUROPSYCHOLOGICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Neli VASILEVA

    2015-11-01

    Full Text Available Introduction: Experimental data in preschool aged children proves the determining role of the auditory and visual processes for future reading skills, therefore the investigation of complex forms of visual perception in this age period is diagnostically important. Objectives: Basic aim of the research is assessment of the sensitive period for the non-verbal perceptive operations in pre-school aged children, and determination of subgroup with low results for non-verbal perception. Methods: The dynamics of the visual per-ception (visual gnosis in typically develop¬ing children were tested with an adapted version of the Poppelreuter-Ghent Test for figure-ground segregation. The total number of overlapping objects is 33, grouped accor¬ding to the level of difficulty. The children are given a group of objects separately in a following sequence and they should segregate and name the objects. Results: A number of 365 typically developing children without diagnosis of visual disorders and without corrected visus took part in the research. All children, aged 4, 5, and 6 from three different settlements attend state nursery schools and have Bulgarian as a mother tongue. A three-factor dispersion analysis was held to define the statistical significance of the independent factors age, gender and settlement. The research’s data define the 5 year olds as sensitive about the dynamics of the complex forms of visual perception, compared to the four year old children (pperceptive operations in the females (F = 1,346, p

  3. The Posture of Putting One's Palms Together Modulates Visual Motion Event Perception.

    Science.gov (United States)

    Saito, Godai; Gyoba, Jiro

    2018-02-01

    We investigated the effect of an observer's hand postures on visual motion perception using the stream/bounce display. When two identical visual objects move across collinear horizontal trajectories toward each other in a two-dimensional display, observers perceive them as either streaming or bouncing. In our previous study, we found that when observers put their palms together just below the coincidence point of the two objects, the percentage of bouncing responses increased, mainly depending on the proprioceptive information from their own hands. However, it remains unclear if the tactile or haptic (force) information produced by the postures mostly influences the stream/bounce perception. We solved this problem by changing the tactile and haptic information on the palms of the hands. Experiment 1 showed that the promotion of bouncing perception was observed only when the posture of directly putting one's palms together was used, while there was no effect when a brick was sandwiched between the participant's palms. Experiment 2 demonstrated that the strength of force used when putting the palms together had no effect on increasing bounce perception. Our findings indicate that the hands-induced bounce effect derives from the tactile information produced by the direct contact between both palms.

  4. The Effect of a Computerized Visual Perception and Visual-Motor Integration Training Program on Improving Chinese Handwriting of Children with Handwriting Difficulties

    Science.gov (United States)

    Poon, K. W.; Li-Tsang, C. W .P.; Weiss, T. P. L.; Rosenblum, S.

    2010-01-01

    This study aimed to investigate the effect of a computerized visual perception and visual-motor integration training program to enhance Chinese handwriting performance among children with learning difficulties, particularly those with handwriting problems. Participants were 26 primary-one children who were assessed by educational psychologists and…

  5. Development of visual motion perception for prospective control: Brain and behavioural studies in infants

    Directory of Open Access Journals (Sweden)

    Seth B. Agyei

    2016-02-01

    Full Text Available During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioural and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioural data when studying the neural correlates of prospective control.

  6. Auditory-visual speech integration by prelinguistic infants: perception of an emergent consonant in the McGurk effect.

    Science.gov (United States)

    Burnham, Denis; Dodd, Barbara

    2004-12-01

    The McGurk effect, in which auditory [ba] dubbed onto [ga] lip movements is perceived as "da" or "tha," was employed in a real-time task to investigate auditory-visual speech perception in prelingual infants. Experiments 1A and 1B established the validity of real-time dubbing for producing the effect. In Experiment 2, 4 1/2-month-olds were tested in a habituation-test paradigm, in which an auditory-visual stimulus was presented contingent upon visual fixation of a live face. The experimental group was habituated to a McGurk stimulus (auditory [ba] visual [ga]), and the control group to matching auditory-visual [ba]. Each group was then presented with three auditory-only test trials, [ba], [da], and [(delta)a] (as in then). Visual-fixation durations in test trials showed that the experimental group treated the emergent percept in the McGurk effect, [da] or [(delta)a], as familiar (even though they had not heard these sounds previously) and [ba] as novel. For control group infants [da] and [(delta)a] were no more familiar than [ba]. These results are consistent with infants' perception of the McGurk effect, and support the conclusion that prelinguistic infants integrate auditory and visual speech information. Copyright 2004 Wiley Periodicals, Inc.

  7. The economics of motion perception and invariants of visual sensitivity.

    Science.gov (United States)

    Gepshtein, Sergei; Tyukin, Ivan; Kubovy, Michael

    2007-06-21

    Neural systems face the challenge of optimizing their performance with limited resources, just as economic systems do. Here, we use tools of neoclassical economic theory to explore how a frugal visual system should use a limited number of neurons to optimize perception of motion. The theory prescribes that vision should allocate its resources to different conditions of stimulation according to the degree of balance between measurement uncertainties and stimulus uncertainties. We find that human vision approximately follows the optimal prescription. The equilibrium theory explains why human visual sensitivity is distributed the way it is and why qualitatively different regimes of apparent motion are observed at different speeds. The theory offers a new normative framework for understanding the mechanisms of visual sensitivity at the threshold of visibility and above the threshold and predicts large-scale changes in visual sensitivity in response to changes in the statistics of stimulation and system goals.

  8. Effects of auditory vection speed and directional congruence on perceptions of visual vection

    Science.gov (United States)

    Gagliano, Isabella Alexis

    Spatial disorientation is a major contributor to aircraft mishaps. One potential contributing factor is vection, an illusion of self-motion. Although vection is commonly thought of as a visual illusion, it can also be produced through audition. The purpose of the current experiment was to explore interactions between conflicting visual and auditory vection cues, specifically with regard to the speed and direction of rotation. The ultimate goal was to explore the extent to which aural vection could diminish or enhance the perception of visual vection. The study used a 3 x 2 within-groups factorial design. Participants were exposed to three levels of aural rotation velocity (slower, matched, and faster, relative to visual rotation speed) and two levels of aural rotational congruence (congruent or incongruent rotation) including two control conditions (visual and aural-only). Dependent measures included vection onset time, vection direction judgements, subjective vection strength ratings, vection speed ratings, and horizontal nystagmus frequency. Subjective responses to motion were assessed pre and post treatment, and oculomotor responses were assessed before, during, and following exposure to circular vection. The results revealed a significant effect of stimulus condition on vection strength. Specifically, directionally-congruent aural-visual vection resulted in significantly stronger vection than visual and aural vection alone. Perceptions of directionally-congruent aural-visual vection were slightly stronger vection than directionally-incongruent aural-visual vection, but not significantly so. No significant effects of aural rotation velocity on vection strength were observed. The results suggest directionally-incongruent aural vection could be used as a countermeasure for visual vection and directionally-congruent aural vection could be used to improve vection in virtual environments, provided further research is done.

  9. Visual perception system and method for a humanoid robot

    Science.gov (United States)

    Wells, James W. (Inventor); Mc Kay, Neil David (Inventor); Chelian, Suhas E. (Inventor); Linn, Douglas Martin (Inventor); Wampler, II, Charles W. (Inventor); Bridgwater, Lyndon (Inventor)

    2012-01-01

    A robotic system includes a humanoid robot with robotic joints each moveable using an actuator(s), and a distributed controller for controlling the movement of each of the robotic joints. The controller includes a visual perception module (VPM) for visually identifying and tracking an object in the field of view of the robot under threshold lighting conditions. The VPM includes optical devices for collecting an image of the object, a positional extraction device, and a host machine having an algorithm for processing the image and positional information. The algorithm visually identifies and tracks the object, and automatically adapts an exposure time of the optical devices to prevent feature data loss of the image under the threshold lighting conditions. A method of identifying and tracking the object includes collecting the image, extracting positional information of the object, and automatically adapting the exposure time to thereby prevent feature data loss of the image.

  10. A Study to Understand the Role of Visual Arts in the Teaching and Learning of Science

    Science.gov (United States)

    Dhanapal, Saroja; Kanapathy, Ravi; Mastan, Jamilah

    2014-01-01

    This research was carried out to understand the role of visual arts in the teaching and learning of science among Grade 3 teachers and students. A mixture of qualitative and quantitative research design was used to discover the different perceptions of both teachers and students on the role of visual arts in science. The data for the research was…

  11. Tuning perception: Visual working memory biases the quality of visual awareness.

    Science.gov (United States)

    Salahub, Christine M; Emrich, Stephen M

    2016-12-01

    Studies of consciousness reveal that it is possible to manipulate subjective awareness of a visual stimulus. For example, items held in visual working memory (VWM) that match target features increase the speed with which the target reaches visual awareness. To examine the effect of VWM on perception, previous studies have mainly used coarse measures of awareness, such as present/absent or forced-choice judgments. These methods can reveal whether or not an individual has seen an item, but they do not provide information about the quality with which the item was seen. Using continuous report methods it has been shown that the fidelity of a perceived item can be affected by whether or not that item is masked. In the present study, we used an object-substitution masking task to examine whether items held in VWM would influence the quality with which a masked target reached awareness, or whether the threshold for awareness was instead affected by stimuli held in memory. We observed that targets matching the contents of VWM were recalled with greater precision compared to items that did not match the contents of VWM. Importantly, this effect occurred without affecting the likelihood of the target being perceived. These results suggest that VWM plays a greater role in modulating the fidelity of perceived representations than in lowering the overall threshold of awareness.

  12. Relations among Grade 4 Students' Perceptions of Autonomy, Engagement in Science, and Reading Motivation

    Science.gov (United States)

    Taboada Barber, Ana; Buehl, Michelle M.

    2013-01-01

    The authors extend previous work on students' perceptions of teachers' autonomy-enhancing and autonomy-suppressing behaviors in relation to students' engagement to a more situated context (i.e., two Grade 4 science instructional conditions instead of school in general) and a linguistically diverse population (i.e., Hispanic students). They also…

  13. Turkish students' perceptions of their biology learning environments: the effects of gender and grade level

    NARCIS (Netherlands)

    Telli, S.; Brok, den P.J.; Tekkaya, C.; Cakiroglu, J.

    2009-01-01

    This study investigates the effects of gender and grade level on Turkish secondary school students’ perceptions of their biology learning environment. A total of 1474 high school students completed the What is Happening in This Classroom (WIHIC) questionnaire. The WIHIC maps several important

  14. Evidence for an All-Or-None Perceptual Response: Single-Trial Analyses of Magnetoencephalography Signals Indicate an Abrupt Transition Between Visual Perception and Its Absence

    Science.gov (United States)

    Sekar, Krithiga; Findley, William M.; Llinás, Rodolfo R.

    2014-01-01

    Whether consciousness is an all-or-none or graded phenomenon is an area of inquiry that has received considerable interest in neuroscience and is as of yet, still debated. In this magnetoencephalography (MEG) study we used a single stimulus paradigm with sub-threshold, threshold and supra-threshold duration inputs to assess whether stimulus perception is continuous with or abruptly differentiated from unconscious stimulus processing in the brain. By grouping epochs according to stimulus identification accuracy and exposure duration, we were able to investigate whether a high-amplitude perception-related cortical event was (1) only evoked for conditions where perception was most probable (2) had invariant amplitude once evoked and (3) was largely absent for conditions where perception was least probable (criteria satisfying an all-on-none hypothesis). We found that averaged evoked responses showed a gradual increase in amplitude with increasing perceptual strength. However, single trial analyses demonstrated that stimulus perception was correlated with an all-or-none response, the temporal precision of which increased systematically as perception transitioned from ambiguous to robust states. Due to poor signal-to-noise resolution of single trial data, whether perception-related responses, whenever present, were invariant in amplitude could not be unambiguously demonstrated. However, our findings strongly suggest that visual perception of simple stimuli is associated with an all-or-none cortical evoked response the temporal precision of which varies as a function of perceptual strength. PMID:22020091

  15. Binocular perception of slant about oblique axes relative to a visual frame of reference

    NARCIS (Netherlands)

    Ee, R. van; Erkelens, Casper J.

    1995-01-01

    From the literature it is known that the processing of disparity for slant is different in the presence and in the absence of a visual frame of reference. We elaborate the experimental finding that vertical disparity is not processed for slant perception in the presence of a visual reference. This

  16. The 50s cliff: a decline in perceptuo-motor learning, not a deficit in visual motion perception.

    Science.gov (United States)

    Ren, Jie; Huang, Shaochen; Zhang, Jiancheng; Zhu, Qin; Wilson, Andrew D; Snapp-Childs, Winona; Bingham, Geoffrey P

    2015-01-01

    Previously, we measured perceptuo-motor learning rates across the lifespan and found a sudden drop in learning rates between ages 50 and 60, called the "50s cliff." The task was a unimanual visual rhythmic coordination task in which participants used a joystick to oscillate one dot in a display in coordination with another dot oscillated by a computer. Participants learned to produce a coordination with a 90° relative phase relation between the dots. Learning rates for participants over 60 were half those of younger participants. Given existing evidence for visual motion perception deficits in people over 60 and the role of visual motion perception in the coordination task, it remained unclear whether the 50s cliff reflected onset of this deficit or a genuine decline in perceptuo-motor learning. The current work addressed this question. Two groups of 12 participants in each of four age ranges (20s, 50s, 60s, 70s) learned to perform a bimanual coordination of 90° relative phase. One group trained with only haptic information and the other group with both haptic and visual information about relative phase. Both groups were tested in both information conditions at baseline and post-test. If the 50s cliff was caused by an age dependent deficit in visual motion perception, then older participants in the visual group should have exhibited less learning than those in the haptic group, which should not exhibit the 50s cliff, and older participants in both groups should have performed less well when tested with visual information. Neither of these expectations was confirmed by the results, so we concluded that the 50s cliff reflects a genuine decline in perceptuo-motor learning with aging, not the onset of a deficit in visual motion perception.

  17. Visual tuning and metrical perception of realistic point-light dance movements

    Science.gov (United States)

    Su, Yi-Huang

    2016-01-01

    Humans move to music spontaneously, and this sensorimotor coupling underlies musical rhythm perception. The present research proposed that, based on common action representation, different metrical levels as in auditory rhythms could emerge visually when observing structured dance movements. Participants watched a point-light figure performing basic steps of Swing dance cyclically in different tempi, whereby the trunk bounced vertically at every beat and the limbs moved laterally at every second beat, yielding two possible metrical periodicities. In Experiment 1, participants freely identified a tempo of the movement and tapped along. While some observers only tuned to the bounce and some only to the limbs, the majority tuned to one level or the other depending on the movement tempo, which was also associated with individuals’ preferred tempo. In Experiment 2, participants reproduced the tempo of leg movements by four regular taps, and showed a slower perceived leg tempo with than without the trunk bouncing simultaneously in the stimuli. This mirrors previous findings of an auditory ‘subdivision effect’, suggesting the leg movements were perceived as beat while the bounce as subdivisions. Together these results support visual metrical perception of dance movements, which may employ similar action-based mechanisms to those underpinning auditory rhythm perception. PMID:26947252

  18. Visual tuning and metrical perception of realistic point-light dance movements.

    Science.gov (United States)

    Su, Yi-Huang

    2016-03-07

    Humans move to music spontaneously, and this sensorimotor coupling underlies musical rhythm perception. The present research proposed that, based on common action representation, different metrical levels as in auditory rhythms could emerge visually when observing structured dance movements. Participants watched a point-light figure performing basic steps of Swing dance cyclically in different tempi, whereby the trunk bounced vertically at every beat and the limbs moved laterally at every second beat, yielding two possible metrical periodicities. In Experiment 1, participants freely identified a tempo of the movement and tapped along. While some observers only tuned to the bounce and some only to the limbs, the majority tuned to one level or the other depending on the movement tempo, which was also associated with individuals' preferred tempo. In Experiment 2, participants reproduced the tempo of leg movements by four regular taps, and showed a slower perceived leg tempo with than without the trunk bouncing simultaneously in the stimuli. This mirrors previous findings of an auditory 'subdivision effect', suggesting the leg movements were perceived as beat while the bounce as subdivisions. Together these results support visual metrical perception of dance movements, which may employ similar action-based mechanisms to those underpinning auditory rhythm perception.

  19. Increase of Universality in Human Brain during Mental Imagery from Visual Perception

    OpenAIRE

    Bhattacharya, Joydeep

    2009-01-01

    BACKGROUND: Different complex systems behave in a similar way near their critical points of phase transitions which leads to an emergence of a universal scaling behaviour. Universality indirectly implies a long-range correlation between constituent subsystems. As the distributed correlated processing is a hallmark of higher complex cognition, I investigated a measure of universality in human brain during perception and mental imagery of complex real-life visual object like visual art. METHODO...

  20. Using auditory-visual speech to probe the basis of noise-impaired consonant-vowel perception in dyslexia and auditory neuropathy

    Science.gov (United States)

    Ramirez, Joshua; Mann, Virginia

    2005-08-01

    Both dyslexics and auditory neuropathy (AN) subjects show inferior consonant-vowel (CV) perception in noise, relative to controls. To better understand these impairments, natural acoustic speech stimuli that were masked in speech-shaped noise at various intensities were presented to dyslexic, AN, and control subjects either in isolation or accompanied by visual articulatory cues. AN subjects were expected to benefit from the pairing of visual articulatory cues and auditory CV stimuli, provided that their speech perception impairment reflects a relatively peripheral auditory disorder. Assuming that dyslexia reflects a general impairment of speech processing rather than a disorder of audition, dyslexics were not expected to similarly benefit from an introduction of visual articulatory cues. The results revealed an increased effect of noise masking on the perception of isolated acoustic stimuli by both dyslexic and AN subjects. More importantly, dyslexics showed less effective use of visual articulatory cues in identifying masked speech stimuli and lower visual baseline performance relative to AN subjects and controls. Last, a significant positive correlation was found between reading ability and the ameliorating effect of visual articulatory cues on speech perception in noise. These results suggest that some reading impairments may stem from a central deficit of speech processing.

  1. The Analysis of Fourth Grade Primary Students' Reader Self-Perceptions in Terms of Gender and Preschool Educational Background

    Science.gov (United States)

    Sagirli, Muhittin; Okur, Burçin

    2017-01-01

    The aim of this study was to analyse perceptions of fourth grade primary school students on their reading ability. In study, screening model was used as a quantitative research method. The sample of this research was selected by convenience sampling. The sample consisted of 556 fourth grade students who received education in 8 public schools in…

  2. Auditory-Visual Speech Perception in Three- and Four-Year-Olds and Its Relationship to Perceptual Attunement and Receptive Vocabulary

    Science.gov (United States)

    Erdener, Dogu; Burnham, Denis

    2018-01-01

    Despite the body of research on auditory-visual speech perception in infants and schoolchildren, development in the early childhood period remains relatively uncharted. In this study, English-speaking children between three and four years of age were investigated for: (i) the development of visual speech perception--lip-reading and visual…

  3. [Perception, processing of visual information and resistance to emotional stresses in athletes of different ages].

    Science.gov (United States)

    Korobeĭnikova, L H; Makarchuk, M Iu

    2013-01-01

    Among the numerous studies devoted to the study of perception and information processing, no data available on the effects of age on these processes. In this paper we studied the influence of psycho-emotional stress and different levels of stress on the mental processes of perception and information processing in highly skilled athletes divided into two groups. The first group included the athletes aged 19-24 years (12 athletes, members of the Ukrainian team in Greco-Roman wrestling), the second group included the athletes aged 27-31 years (7 highly skilled athletes, members of the Ukrainian team in Greco-Roman wrestling). We revealed that the athletes of the first group had higher productivity and better visual perception and visual information processing efficiency, compared with athletes from the second group. This observation suggests a dependency of cognitive component of perception and information processing on the age of the athletes. Sportsmen from the second group had higher stress resistance compared to the older age group.

  4. A Neural Circuit for Auditory Dominance over Visual Perception.

    Science.gov (United States)

    Song, You-Hyang; Kim, Jae-Hyun; Jeong, Hye-Won; Choi, Ilsong; Jeong, Daun; Kim, Kwansoo; Lee, Seung-Hee

    2017-02-22

    When conflicts occur during integration of visual and auditory information, one modality often dominates the other, but the underlying neural circuit mechanism remains unclear. Using auditory-visual discrimination tasks for head-fixed mice, we found that audition dominates vision in a process mediated by interaction between inputs from the primary visual (VC) and auditory (AC) cortices in the posterior parietal cortex (PTLp). Co-activation of the VC and AC suppresses VC-induced PTLp responses, leaving AC-induced responses. Furthermore, parvalbumin-positive (PV+) interneurons in the PTLp mainly receive AC inputs, and muscimol inactivation of the PTLp or optogenetic inhibition of its PV+ neurons abolishes auditory dominance in the resolution of cross-modal sensory conflicts without affecting either sensory perception. Conversely, optogenetic activation of PV+ neurons in the PTLp enhances the auditory dominance. Thus, our results demonstrate that AC input-specific feedforward inhibition of VC inputs in the PTLp is responsible for the auditory dominance during cross-modal integration. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Perception of the dynamic visual vertical during sinusoidal linear motion.

    Science.gov (United States)

    Pomante, A; Selen, L P J; Medendorp, W P

    2017-10-01

    The vestibular system provides information for spatial orientation. However, this information is ambiguous: because the otoliths sense the gravitoinertial force, they cannot distinguish gravitational and inertial components. As a consequence, prolonged linear acceleration of the head can be interpreted as tilt, referred to as the somatogravic effect. Previous modeling work suggests that the brain disambiguates the otolith signal according to the rules of Bayesian inference, combining noisy canal cues with the a priori assumption that prolonged linear accelerations are unlikely. Within this modeling framework the noise of the vestibular signals affects the dynamic characteristics of the tilt percept during linear whole-body motion. To test this prediction, we devised a novel paradigm to psychometrically characterize the dynamic visual vertical-as a proxy for the tilt percept-during passive sinusoidal linear motion along the interaural axis (0.33 Hz motion frequency, 1.75 m/s 2 peak acceleration, 80 cm displacement). While subjects ( n =10) kept fixation on a central body-fixed light, a line was briefly flashed (5 ms) at different phases of the motion, the orientation of which had to be judged relative to gravity. Consistent with the model's prediction, subjects showed a phase-dependent modulation of the dynamic visual vertical, with a subject-specific phase shift with respect to the imposed acceleration signal. The magnitude of this modulation was smaller than predicted, suggesting a contribution of nonvestibular signals to the dynamic visual vertical. Despite their dampening effect, our findings may point to a link between the noise components in the vestibular system and the characteristics of dynamic visual vertical. NEW & NOTEWORTHY A fundamental question in neuroscience is how the brain processes vestibular signals to infer the orientation of the body and objects in space. We show that, under sinusoidal linear motion, systematic error patterns appear in the

  6. Attention and visual memory in visualization and computer graphics.

    Science.gov (United States)

    Healey, Christopher G; Enns, James T

    2012-07-01

    A fundamental goal of visualization is to produce images of data that support visual analysis, exploration, and discovery of novel insights. An important consideration during visualization design is the role of human visual perception. How we "see" details in an image can directly impact a viewer's efficiency and effectiveness. This paper surveys research on attention and visual perception, with a specific focus on results that have direct relevance to visualization and visual analytics. We discuss theories of low-level visual perception, then show how these findings form a foundation for more recent work on visual memory and visual attention. We conclude with a brief overview of how knowledge of visual attention and visual memory is being applied in visualization and graphics. We also discuss how challenges in visualization are motivating research in psychophysics.

  7. SoftAR: visually manipulating haptic softness perception in spatial augmented reality.

    Science.gov (United States)

    Punpongsanon, Parinya; Iwai, Daisuke; Sato, Kosuke

    2015-11-01

    We present SoftAR, a novel spatial augmented reality (AR) technique based on a pseudo-haptics mechanism that visually manipulates the sense of softness perceived by a user pushing a soft physical object. Considering the limitations of projection-based approaches that change only the surface appearance of a physical object, we propose two projection visual effects, i.e., surface deformation effect (SDE) and body appearance effect (BAE), on the basis of the observations of humans pushing physical objects. The SDE visualizes a two-dimensional deformation of the object surface with a controlled softness parameter, and BAE changes the color of the pushing hand. Through psychophysical experiments, we confirm that the SDE can manipulate softness perception such that the participant perceives significantly greater softness than the actual softness. Furthermore, fBAE, in which BAE is applied only for the finger area, significantly enhances manipulation of the perception of softness. We create a computational model that estimates perceived softness when SDE+fBAE is applied. We construct a prototype SoftAR system in which two application frameworks are implemented. The softness adjustment allows a user to adjust the softness parameter of a physical object, and the softness transfer allows the user to replace the softness with that of another object.

  8. Processing reafferent and exafferent visual information for action and perception.

    Science.gov (United States)

    Reichenbach, Alexandra; Diedrichsen, Jörn

    2015-01-01

    A recent study suggests that reafferent hand-related visual information utilizes a privileged, attention-independent processing channel for motor control. This process was termed visuomotor binding to reflect its proposed function: linking visual reafferences to the corresponding motor control centers. Here, we ask whether the advantage of processing reafferent over exafferent visual information is a specific feature of the motor processing stream or whether the improved processing also benefits the perceptual processing stream. Human participants performed a bimanual reaching task in a cluttered visual display, and one of the visual hand cursors could be displaced laterally during the movement. We measured the rapid feedback responses of the motor system as well as matched perceptual judgments of which cursor was displaced. Perceptual judgments were either made by watching the visual scene without moving or made simultaneously to the reaching tasks, such that the perceptual processing stream could also profit from the specialized processing of reafferent information in the latter case. Our results demonstrate that perceptual judgments in the heavily cluttered visual environment were improved when performed based on reafferent information. Even in this case, however, the filtering capability of the perceptual processing stream suffered more from the increasing complexity of the visual scene than the motor processing stream. These findings suggest partly shared and partly segregated processing of reafferent information for vision for motor control versus vision for perception.

  9. Distributed consensus with visual perception in multi-robot systems

    CERN Document Server

    Montijano, Eduardo

    2015-01-01

    This monograph introduces novel responses to the different problems that arise when multiple robots need to execute a task in cooperation, each robot in the team having a monocular camera as its primary input sensor. Its central proposition is that a consistent perception of the world is crucial for the good development of any multi-robot application. The text focuses on the high-level problem of cooperative perception by a multi-robot system: the idea that, depending on what each robot sees and its current situation, it will need to communicate these things to its fellows whenever possible to share what it has found and keep updated by them in its turn. However, in any realistic scenario, distributed solutions to this problem are not trivial and need to be addressed from as many angles as possible. Distributed Consensus with Visual Perception in Multi-Robot Systems covers a variety of related topics such as: ·         distributed consensus algorithms; ·         data association and robustne...

  10. Relationship between Vision and Visual Perception in Hong Kong Preschoolers.

    Science.gov (United States)

    Ho, Wing-Cheung; Tang, Minny Mei-Miu; Fu, Ching-Wah; Leung, Ka-Yan; Pang, Peter Chi-Kong; Cheong, Allen Ming-Yan

    2015-05-01

    Although superior performance in visual motor and visual perceptual skills of preschool children has been documented in the Chinese population, a normative database is only available for the US population. This study aimed to determine the normative values for these visuomotor and visual perceptual tests for preschool children in the Hong Kong Chinese population and to investigate the effect of fundamental visual functions on visuomotor and visual perceptual skills. One hundred seventy-four children from six different kindergartens in Hong Kong were recruited. Distance visual acuity, near visual acuity, and stereopsis were tested, along with two measures of visual perception (VP): Visual-Motor Integration (VMI) and Test of Visual-Perceptual Skills (TVPS). Raw VMI and TVPS scores were converted into standard/scaled scores. The impact of basic visual functions on VP (VMI and TVPS) was examined using multiple regression. Visual functions were generally good: only 9.2 and 4.6% of subjects had unilateral and bilateral reduced habitual vision, respectively (distance visual acuity in the better eye >0.3 logMAR [logarithm of the minimum angle of resolution]). Performance in the VMI and in the visual memory and spatial relationships subtests of the TVPS exceeded that reported for age-matched children from the United States. Multiple regression analysis provided evidence that age had the strongest predictive value for the VMI and VP skills. In addition, near visual acuity was weakly associated with performance in the VMI and the visual discrimination and spatial relationships subtests of the TVPS, accounting for a limited proportion of the intersubject variability (R memory/spatial relationships of TVPS subtests, perhaps attributed to greater exposure to such material during their preschool home education. This study provided normality data for VMI and four subtests of the TVPS for Hong Kong Chinese preschool children as a reference for future studies.

  11. Correlation between electrical and hemodynamic responses during visual stimulation with graded contrasts

    Science.gov (United States)

    Si, Juanning; Zhang, Xin; Li, Yuejun; Zhang, Yujin; Zuo, Nianming; Jiang, Tianzi

    2016-09-01

    Brain functional activity involves complex cellular, metabolic, and vascular chain reactions, making it difficult to comprehend. Electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) have been combined into a multimodal neuroimaging method that captures both electrophysiological and hemodynamic information to explore the spatiotemporal characteristics of brain activity. Because of the significance of visually evoked functional activity in clinical applications, numerous studies have explored the amplitude of the visual evoked potential (VEP) to clarify its relationship with the hemodynamic response. However, relatively few studies have investigated the influence of latency, which has been frequently used to diagnose visual diseases, on the hemodynamic response. Moreover, because the latency and the amplitude of VEPs have different roles in coding visual information, investigating the relationship between latency and the hemodynamic response should be helpful. In this study, checkerboard reversal tasks with graded contrasts were used to evoke visual functional activity. Both EEG and fNIRS were employed to investigate the relationship between neuronal electrophysiological activities and the hemodynamic responses. The VEP amplitudes were linearly correlated with the hemodynamic response, but the VEP latency showed a negative linear correlation with the hemodynamic response.

  12. Top-down control of visual perception: attention in natural vision.

    Science.gov (United States)

    Rolls, Edmund T

    2008-01-01

    Top-down perceptual influences can bias (or pre-empt) perception. In natural scenes, the receptive fields of neurons in the inferior temporal visual cortex (IT) shrink to become close to the size of objects. This facilitates the read-out of information from the ventral visual system, because the information is primarily about the object at the fovea. Top-down attentional influences are much less evident in natural scenes than when objects are shown against blank backgrounds, though are still present. It is suggested that the reduced receptive-field size in natural scenes, and the effects of top-down attention contribute to change blindness. The receptive fields of IT neurons in complex scenes, though including the fovea, are frequently asymmetric around the fovea, and it is proposed that this is the solution the IT uses to represent multiple objects and their relative spatial positions in a scene. Networks that implement probabilistic decision-making are described, and it is suggested that, when in perceptual systems they take decisions (or 'test hypotheses'), they influence lower-level networks to bias visual perception. Finally, it is shown that similar processes extend to systems involved in the processing of emotion-provoking sensory stimuli, in that word-level cognitive states provide top-down biasing that reaches as far down as the orbitofrontal cortex, where, at the first stage of affective representations, olfactory, taste, flavour, and touch processing is biased (or pre-empted) in humans.

  13. Developmental visual perception deficits with no indications of prosopagnosia in a child with abnormal eye movements.

    Science.gov (United States)

    Gilaie-Dotan, Sharon; Doron, Ravid

    2017-06-01

    Visual categories are associated with eccentricity biases in high-order visual cortex: Faces and reading with foveally-biased regions, while common objects and space with mid- and peripherally-biased regions. As face perception and reading are among the most challenging human visual skills, and are often regarded as the peak achievements of a distributed neural network supporting common objects perception, it is unclear why objects, which also rely on foveal vision to be processed, are associated with mid-peripheral rather than with a foveal bias. Here, we studied BN, a 9 y.o. boy who has normal basic-level vision, abnormal (limited) oculomotor pursuit and saccades, and shows developmental object and contour integration deficits but with no indication of prosopagnosia. Although we cannot infer causation from the data presented here, we suggest that normal pursuit and saccades could be critical for the development of contour integration and object perception. While faces and perhaps reading, when fixated upon, take up a small portion of central visual field and require only small eye movements to be properly processed, common objects typically prevail in mid-peripheral visual field and rely on longer-distance voluntary eye movements as saccades to be brought to fixation. While retinal information feeds into early visual cortex in an eccentricity orderly manner, we hypothesize that propagation of non-foveal information to mid and high-order visual cortex critically relies on circuitry involving eye movements. Limited or atypical eye movements, as in the case of BN, may hinder normal information flow to mid-eccentricity biased high-order visual cortex, adversely affecting its development and consequently inducing visual perceptual deficits predominantly for categories associated with these regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Relationships between academic performance, SES school type and perceptual-motor skills in first grade South African learners: NW-CHILD study.

    Science.gov (United States)

    Pienaar, A E; Barhorst, R; Twisk, J W R

    2014-05-01

    Perceptual-motor skills contribute to a variety of basic learning skills associated with normal academic success. This study aimed to determine the relationship between academic performance and perceptual-motor skills in first grade South African learners and whether low SES (socio-economic status) school type plays a role in such a relationship. This cross-sectional study of the baseline measurements of the NW-CHILD longitudinal study included a stratified random sample of first grade learners (n = 812; 418 boys and 394 boys), with a mean age of 6.78 years ± 0.49 living in the North West Province (NW) of South Africa. The Beery-Buktenica Developmental Test of Visual-Motor Integration-4 (VMI) was used to assess visual-motor integration, visual perception and hand control while the Bruininks Oseretsky Test of Motor Proficiency, short form (BOT2-SF) assessed overall motor proficiency. Academic performance in math, reading and writing was assessed with the Mastery of Basic Learning Areas Questionnaire. Linear mixed models analysis was performed with spss to determine possible differences between the different VMI and BOT2-SF standard scores in different math, reading and writing mastery categories ranging from no mastery to outstanding mastery. A multinomial multilevel logistic regression analysis was performed to assess the relationship between a clustered score of academic performance and the different determinants. A strong relationship was established between academic performance and VMI, visual perception, hand control and motor proficiency with a significant relationship between a clustered academic performance score, visual-motor integration and visual perception. A negative association was established between low SES school types on academic performance, with a common perceptual motor foundation shared by all basic learning areas. Visual-motor integration, visual perception, hand control and motor proficiency are closely related to basic academic skills

  15. University Teachers' Perception of Inclusion of Visually Impaired in Ghanaian Universities

    Science.gov (United States)

    Mamah, Vincent; Deku, Prosper; Darling, Sharon M.; Avoke, Selete K.

    2011-01-01

    This study was undertaken to examine the university teachers' perception of including students with Visual Impairment (VI) in the public universities of Ghana. The sample consisted of 110 teachers from the University of Cape Coast (UCC), the University of Education, Winneba, (UEW), and the University of Ghana (UG). Data were collected through…

  16. Visual perception and attention in acquisition of motor abilities

    Directory of Open Access Journals (Sweden)

    César Oliva Aravena

    2008-06-01

    Full Text Available This article present a qualitative analysis, relating visual perception to attention in the acquisition of motor abilities process. Research shows that the visual system is already in an advanced stage, right from the moment the baby is born, and that normal eye sight is attained at the age of 5 and continues to improve. On the other hand, attention is an flexible process, subordinated to a cognitive strategy and its relation to eye sight is only functional. The understanfing of the capacity of selective attention is necessary to the teacher or coach for it will help him/her to take decisions on how to teach, which aspects of his/her teaching should be emphasized or inhibited, in the learning process, and wich teaching strategies he/she should use.

  17. Perception of linear horizontal self-motion induced by peripheral vision /linearvection/ - Basic characteristics and visual-vestibular interactions

    Science.gov (United States)

    Berthoz, A.; Pavard, B.; Young, L. R.

    1975-01-01

    The basic characteristics of the sensation of linear horizontal motion have been studied. Objective linear motion was induced by means of a moving cart. Visually induced linear motion perception (linearvection) was obtained by projection of moving images at the periphery of the visual field. Image velocity and luminance thresholds for the appearance of linearvection have been measured and are in the range of those for image motion detection (without sensation of self motion) by the visual system. Latencies of onset are around 1 sec and short term adaptation has been shown. The dynamic range of the visual analyzer as judged by frequency analysis is lower than the vestibular analyzer. Conflicting situations in which visual cues contradict vestibular and other proprioceptive cues show, in the case of linearvection a dominance of vision which supports the idea of an essential although not independent role of vision in self motion perception.

  18. Examining the Effect of Age on Visual-Vestibular Self-Motion Perception Using a Driving Paradigm.

    Science.gov (United States)

    Ramkhalawansingh, Robert; Keshavarz, Behrang; Haycock, Bruce; Shahab, Saba; Campos, Jennifer L

    2017-05-01

    Previous psychophysical research has examined how younger adults and non-human primates integrate visual and vestibular cues to perceive self-motion. However, there is much to be learned about how multisensory self-motion perception changes with age, and how these changes affect performance on everyday tasks involving self-motion. Evidence suggests that older adults display heightened multisensory integration compared with younger adults; however, few previous studies have examined this for visual-vestibular integration. To explore age differences in the way that visual and vestibular cues contribute to self-motion perception, we had younger and older participants complete a basic driving task containing visual and vestibular cues. We compared their performance against a previously established control group that experienced visual cues alone. Performance measures included speed, speed variability, and lateral position. Vestibular inputs resulted in more precise speed control among older adults, but not younger adults, when traversing curves. Older adults demonstrated more variability in lateral position when vestibular inputs were available versus when they were absent. These observations align with previous evidence of age-related differences in multisensory integration and demonstrate that they may extend to visual-vestibular integration. These findings may have implications for vehicle and simulator design when considering older users.

  19. Perceptions of Elementary School Students: Experiences and Dreams about the Life Studies Course

    Science.gov (United States)

    Baysal, Z. Nurdan; Tezcan, Özlem Apak; Araç, Kamil Ersin

    2018-01-01

    This study seeks to identify elementary school students' views and perceptions of the Life Studies course through verbal and visual instruments. It employs a descriptive phenomenological research design. The study surveyed second- and third-grade students attending one private elementary school and two state elementary schools. The data was…

  20. Human alteration of the rural landscape: Variations in visual perception

    International Nuclear Information System (INIS)

    Cloquell-Ballester, Vicente-Agustín; Carmen Torres-Sibille, Ana del; Cloquell-Ballester, Víctor-Andrés; Santamarina-Siurana, María Cristina

    2012-01-01

    The objective of this investigation is to evaluate how visual perception varies as the rural landscape is altered by human interventions of varying character. An experiment is carried out using Semantic Differential Analysis to analyse the effect of the character and the type of the intervention on perception. Interventions are divided into elements of “permanent industrial character”, “elements of permanent rural character” and “elements of temporary character”, and these categories are sub-divided into smaller groups according to the type of development. To increase the reliability of the results, the Intraclass Correlation Coefficient tool, is applied to validate the semantic space of the perceptual responses and to determine the number of subjects required for a reliable evaluation of the scenes.

  1. Human alteration of the rural landscape: Variations in visual perception

    Energy Technology Data Exchange (ETDEWEB)

    Cloquell-Ballester, Vicente-Agustin, E-mail: cloquell@dpi.upv.es; Carmen Torres-Sibille, Ana del; Cloquell-Ballester, Victor-Andres; Santamarina-Siurana, Maria Cristina

    2012-01-15

    The objective of this investigation is to evaluate how visual perception varies as the rural landscape is altered by human interventions of varying character. An experiment is carried out using Semantic Differential Analysis to analyse the effect of the character and the type of the intervention on perception. Interventions are divided into elements of 'permanent industrial character', 'elements of permanent rural character' and 'elements of temporary character', and these categories are sub-divided into smaller groups according to the type of development. To increase the reliability of the results, the Intraclass Correlation Coefficient tool, is applied to validate the semantic space of the perceptual responses and to determine the number of subjects required for a reliable evaluation of the scenes.

  2. Dissociation between the neural correlates of conscious face perception and visual attention.

    Science.gov (United States)

    Navajas, Joaquin; Nitka, Aleksander W; Quian Quiroga, Rodrigo

    2017-08-01

    Given the higher chance to recognize attended compared to unattended stimuli, the specific neural correlates of these two processes, attention and awareness, tend to be intermingled in experimental designs. In this study, we dissociated the neural correlates of conscious face perception from the effects of visual attention. To do this, we presented faces at the threshold of awareness and manipulated attention through the use of exogenous prestimulus cues. We show that the N170 component, a scalp EEG marker of face perception, was modulated independently by attention and by awareness. An earlier P1 component was not modulated by either of the two effects and a later P3 component was indicative of awareness but not of attention. These claims are supported by converging evidence from (a) modulations observed in the average evoked potentials, (b) correlations between neural and behavioral data at the single-subject level, and (c) single-trial analyses. Overall, our results show a clear dissociation between the neural substrates of attention and awareness. Based on these results, we argue that conscious face perception is triggered by a boost in face-selective cortical ensembles that can be modulated by, but are still independent from, visual attention. © 2017 Society for Psychophysiological Research.

  3. [The impact of psilocybin on visual perception and spatial orientation--neuropsychological approach].

    Science.gov (United States)

    Jastrzebski, Mikolaj; Bala, Aleksandra

    2013-01-01

    Psilocybin is a substance of natural origin, occurring in hallucinogenic mushrooms (most common in the Psilocybe family). After its synthesis in 1958 research began on its psychoactive properties, particularly strong effects on visual perception and spatial orientation. Due to the very broad spectrum of psilocybin effects research began on the different ranges of its actions--including the effect on physiological processes (such as eye saccada movements). Neuro-imaging and neurophysiological research (positron emission tomography-PET and electroencephalography-EEG), indicate a change in the rate of metabolism of the brain and desync cerebral hemispheres. Experimental studies show the changes in visual perception and distortion from psilocybin in the handwriting style of patients examined. There are widely described subjective experiences reported by the subjects. There are also efforts to apply testing via questionnaire on people under the influence of psilocybin, in the context of the similarity of psilocybin-induced state to the initial stages of schizophrenia, as well as research aimed at creating an 'artificial' model of the disease.

  4. The spatially asymmetric cost of memory load on visual perception: transient stimulus-centered neglect.

    Science.gov (United States)

    Gozli, Davood G; Wilson, Kristin E; Ferber, Susanne

    2014-04-01

    Recent evidence suggests that visual working memory (VWM) load reduces performance accuracy on a concurrent visual recognition task, particularly for objects presented in the left hemifield. It has also been shown that high VWM load causes suppression of activity in the right temporoparietal junction (TPJ). Given the resemblance of VWM load effects to symptoms of unilateral neglect (i.e., impaired perception on the left side and lesion to the right TPJ), we investigated whether VWM load effects are restricted to the left side of space or extend to object-centered reference frames. In other words, akin to object-centered neglect, can high VWM load cause a perceptual cost in attending to the left side of the stimulus? We addressed this question using an object recognition task (Experiment 1) and a visual search task (Experiment 2) showing that this transient left-neglect can indeed be modulated by an object-centered frame of reference. These findings suggest that load-induced impairments of visual attention are spatially asymmetric and can emerge within multiple spatial reference frames. Therefore, the attentional consequences of high VWM load on conscious perception may serve as a useful model of unilateral perceptual neglect.

  5. The contribution of dynamic visual cues to audiovisual speech perception.

    Science.gov (United States)

    Jaekl, Philip; Pesquita, Ana; Alsius, Agnes; Munhall, Kevin; Soto-Faraco, Salvador

    2015-08-01

    Seeing a speaker's facial gestures can significantly improve speech comprehension, especially in noisy environments. However, the nature of the visual information from the speaker's facial movements that is relevant for this enhancement is still unclear. Like auditory speech signals, visual speech signals unfold over time and contain both dynamic configural information and luminance-defined local motion cues; two information sources that are thought to engage anatomically and functionally separate visual systems. Whereas, some past studies have highlighted the importance of local, luminance-defined motion cues in audiovisual speech perception, the contribution of dynamic configural information signalling changes in form over time has not yet been assessed. We therefore attempted to single out the contribution of dynamic configural information to audiovisual speech processing. To this aim, we measured word identification performance in noise using unimodal auditory stimuli, and with audiovisual stimuli. In the audiovisual condition, speaking faces were presented as point light displays achieved via motion capture of the original talker. Point light displays could be isoluminant, to minimise the contribution of effective luminance-defined local motion information, or with added luminance contrast, allowing the combined effect of dynamic configural cues and local motion cues. Audiovisual enhancement was found in both the isoluminant and contrast-based luminance conditions compared to an auditory-only condition, demonstrating, for the first time the specific contribution of dynamic configural cues to audiovisual speech improvement. These findings imply that globally processed changes in a speaker's facial shape contribute significantly towards the perception of articulatory gestures and the analysis of audiovisual speech. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Visual Memories Bypass Normalization.

    Science.gov (United States)

    Bloem, Ilona M; Watanabe, Yurika L; Kibbe, Melissa M; Ling, Sam

    2018-05-01

    How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores-neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation.

  7. Effects of Visual Food Texture on Taste Perception

    Directory of Open Access Journals (Sweden)

    Katsunori Okajima

    2011-10-01

    Full Text Available Food color affects taste perception. However, the possible effects of the visual texture of a foodstuff on taste and flavor, without associated changes to color, are currently unknown. We conducted a series of experiments designed to investigate how the visual texture and appearance of food influences its perceived taste and flavor by developing an Augmented Reality system. Participants observed a video of tomato ketchup as a food stimulus on a white dish placed behind a flat LC-display on which was mounted a video camera. The luminance distribution of the ketchup in the dynamic video was continuously and quantitatively modified by tracking specified colors in real-time. We changed the skewness of the luminance histogram of each frame in the video keeping the xy-chromaticity values intact. Participants watched themselves dip a spoon into the ketchup from the video feed (which could be altered, but then ate it with their eyes closed. They reported before and after tasting the ketchup on the perceived consistency (a liquid to solid continuum the food looked and felt and how tasty it looked or felt. The experimental results suggest that visual texture, independent of color, affects the taste and flavor as well as the appearance of foods.

  8. Quality-Related Monitoring and Grading of Granulated Products by Weibull-Distribution Modeling of Visual Images with Semi-Supervised Learning.

    Science.gov (United States)

    Liu, Jinping; Tang, Zhaohui; Xu, Pengfei; Liu, Wenzhong; Zhang, Jin; Zhu, Jianyong

    2016-06-29

    The topic of online product quality inspection (OPQI) with smart visual sensors is attracting increasing interest in both the academic and industrial communities on account of the natural connection between the visual appearance of products with their underlying qualities. Visual images captured from granulated products (GPs), e.g., cereal products, fabric textiles, are comprised of a large number of independent particles or stochastically stacking locally homogeneous fragments, whose analysis and understanding remains challenging. A method of image statistical modeling-based OPQI for GP quality grading and monitoring by a Weibull distribution(WD) model with a semi-supervised learning classifier is presented. WD-model parameters (WD-MPs) of GP images' spatial structures, obtained with omnidirectional Gaussian derivative filtering (OGDF), which were demonstrated theoretically to obey a specific WD model of integral form, were extracted as the visual features. Then, a co-training-style semi-supervised classifier algorithm, named COSC-Boosting, was exploited for semi-supervised GP quality grading, by integrating two independent classifiers with complementary nature in the face of scarce labeled samples. Effectiveness of the proposed OPQI method was verified and compared in the field of automated rice quality grading with commonly-used methods and showed superior performance, which lays a foundation for the quality control of GP on assembly lines.

  9. The interplay of language and visual perception in working memory.

    Science.gov (United States)

    Souza, Alessandra S; Skóra, Zuzanna

    2017-09-01

    How do perception and language interact to form the representations that guide our thoughts and actions over the short-term? Here, we provide a first examination of this question by investigating the role of verbal labels in a continuous visual working memory (WM) task. Across four experiments, participants retained in memory the continuous color of a set of dots which were presented sequentially (Experiments 1-3) or simultaneously (Experiment 4). At test, they reproduced the colors of all dots using a color wheel. During stimulus presentation participants were required to either label the colors (color labeling) or to repeat "bababa" aloud (articulatory suppression), hence prompting or preventing verbal labeling, respectively. We tested four competing hypotheses of the labeling effect: (1) labeling generates a verbal representation that overshadows the visual representation; (2) labeling yields a verbal representation in addition to the visual one; (3) the labels function as a retrieval cue, adding distinctiveness to items in memory; and (4) labels activate visual categorical representations in long-term memory. Collectively, our experiments show that labeling does not overshadow the visual input; it augments it. Mixture modeling showed that labeling increased the quantity and quality of information in WM. Our findings are consistent with the hypothesis that labeling activates visual long-term categorical representations which help in reducing the noise in the internal representations of the visual stimuli in WM. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. From elements to perception: local and global processing in visual neurons.

    Science.gov (United States)

    Spillmann, L

    1999-01-01

    Gestalt psychologists in the early part of the century challenged psychophysical notions that perceptual phenomena can be understood from a punctate (atomistic) analysis of the elements present in the stimulus. Their ideas slowed later attempts to explain vision in terms of single-cell recordings from individual neurons. A rapprochement between Gestalt phenomenology and neurophysiology seemed unlikely when the first ECVP was held in Marburg, Germany, in 1978. Since that time, response properties of neurons have been discovered that invite an interpretation of visual phenomena (including illusions) in terms of neuronal processing by long-range interactions, as first proposed by Mach and Hering in the last century. This article traces a personal journey into the early days of neurophysiological vision research to illustrate the progress that has taken place from the first attempts to correlate single-cell responses with visual perceptions. Whereas initially the receptive-field properties of individual classes of cells--e.g., contrast, wavelength, orientation, motion, disparity, and spatial-frequency detectors--were used to account for relatively simple visual phenomena, nowadays complex perceptions are interpreted in terms of long-range interactions, involving many neurons. This change in paradigm from local to global processing was made possible by recent findings, in the cortex, on horizontal interactions and backward propagation (feedback loops) in addition to classical feedforward processing. These mechanisms are exemplified by studies of the tilt effect and tilt aftereffect, direction-specific motion adaptation, illusory contours, filling-in and fading, figure--ground segregation by orientation and motion contrast, and pop-out in dynamic visual-noise patterns. Major questions for future research and a discussion of their epistemological implications conclude the article.

  11. Steady-state visually evoked potential correlates of human body perception.

    Science.gov (United States)

    Giabbiconi, Claire-Marie; Jurilj, Verena; Gruber, Thomas; Vocks, Silja

    2016-11-01

    In cognitive neuroscience, interest in the neuronal basis underlying the processing of human bodies is steadily increasing. Based on functional magnetic resonance imaging studies, it is assumed that the processing of pictures of human bodies is anchored in a network of specialized brain areas comprising the extrastriate and the fusiform body area (EBA, FBA). An alternative to examine the dynamics within these networks is electroencephalography, more specifically so-called steady-state visually evoked potentials (SSVEPs). In SSVEP tasks, a visual stimulus is presented repetitively at a predefined flickering rate and typically elicits a continuous oscillatory brain response at this frequency. This brain response is characterized by an excellent signal-to-noise ratio-a major advantage for source reconstructions. The main goal of present study was to demonstrate the feasibility of this method to study human body perception. To that end, we presented pictures of bodies and contrasted the resulting SSVEPs to two control conditions, i.e., non-objects and pictures of everyday objects (chairs). We found specific SSVEPs amplitude differences between bodies and both control conditions. Source reconstructions localized the SSVEP generators to a network of temporal, occipital and parietal areas. Interestingly, only body perception resulted in activity differences in middle temporal and lateral occipitotemporal areas, most likely reflecting the EBA/FBA.

  12. Preoperative Quantitative MR Tractography Compared with Visual Tract Evaluation in Patients with Neuropathologically Confirmed Gliomas Grades II and III: A Prospective Cohort Study

    International Nuclear Information System (INIS)

    Delgado, Anna F.; Nilsson, Markus; Latini, Francesco; Mårtensson, Johanna; Zetterling, Maria; Berntsson, Shala G.; Alafuzoff, Irina; Lätt, Jimmy; Larsson, Elna-Marie

    2016-01-01

    Background and Purpose. Low-grade gliomas show infiltrative growth in white matter tracts. Diffusion tensor tractography can noninvasively assess white matter tracts. The aim was to preoperatively assess tumor growth in white matter tracts using quantitative MR tractography (3T). The hypothesis was that suspected infiltrated tracts would have altered diffusional properties in infiltrated tract segments compared to noninfiltrated tracts. Materials and Methods. Forty-eight patients with suspected low-grade glioma were included after written informed consent and underwent preoperative diffusion tensor imaging in this prospective review-board approved study. Major white matter tracts in both hemispheres were tracked, segmented, and visually assessed for tumor involvement in thirty-four patients with gliomas grade II or III (astrocytomas or oligodendrogliomas) on postoperative neuropathological evaluation. Relative fractional anisotropy (rFA) and mean diffusivity (rMD) in tract segments were calculated and compared with visual evaluation and neuropathological diagnosis. Results. Tract segment infiltration on visual evaluation was associated with a lower rFA and high rMD in a majority of evaluated tract segments (89% and 78%, resp.). Grade II and grade III gliomas had similar infiltrating behavior. Conclusion. Quantitative MR tractography corresponds to visual evaluation of suspected tract infiltration. It may be useful for an objective preoperative evaluation of tract segment involvement

  13. Visual health and social perception of jugglers in the city of Bogotá, Colombia

    Directory of Open Access Journals (Sweden)

    Kelly Nataly Rincón-Suárez

    2017-12-01

    Full Text Available Introduction: Juggling is an artistic practice that includes various historical, social, cultural and economic dynamics, and nowadays it conceives new approaches regarding the artist's health. Objective: To understand the state of visual health and the social perception of juggling in the city of Bogotá. Materials and methods: A mixed study combining qualitative methodology of phenomenological type a quantitative descriptive methodology in a group of 15 jugglers of the city of Bogota, who worked at the traffic lights in the localities of Teusaquillo, Suba and Engativá, through three stages: planning; field work which includes field diary, interview and visual and ocular screening tests; and advertising campaign. Results: 100% of the participants referred to eye reddening and feeling of grit that is associated with the working hours, manipulation tools and exposure to the work environment. There are normally in the perception of depth (20" of arc and the perception of color in the totality of participants. Conclusions: Visual and ocular health is not very important for the participating jugglers; however, they have symptoms of ocular discomfort. The juggler is perceived as a social actor that contributes to the growth of the city no matter that the common people consider this practice as unhealthy. The designed social campaign managed to sensitize pedestrians and drivers.

  14. Cortical Double-Opponent Cells in Color Perception: Perceptual Scaling and Chromatic Visual Evoked Potentials.

    Science.gov (United States)

    Nunez, Valerie; Shapley, Robert M; Gordon, James

    2018-01-01

    In the early visual cortex V1, there are currently only two known neural substrates for color perception: single-opponent and double-opponent cells. Our aim was to explore the relative contributions of these neurons to color perception. We measured the perceptual scaling of color saturation for equiluminant color checkerboard patterns (designed to stimulate double-opponent neurons preferentially) and uniformly colored squares (designed to stimulate only single-opponent neurons) at several cone contrasts. The spatially integrative responses of single-opponent neurons would produce the same response magnitude for checkerboards as for uniform squares of the same space-averaged cone contrast. However, perceived saturation of color checkerboards was higher than for the corresponding squares. The perceptual results therefore imply that double-opponent cells are involved in color perception of patterns. We also measured the chromatic visual evoked potential (cVEP) produced by the same stimuli; checkerboard cVEPs were much larger than those for corresponding squares, implying that double-opponent cells also contribute to the cVEP response. The total Fourier power of the cVEP grew sublinearly with cone contrast. However, the 6-Hz Fourier component's power grew linearly with contrast-like saturation perception. This may also indicate that cortical coding of color depends on response dynamics.

  15. The effects of pattern shape, subliminal stimulation, and voluntary control on multistable visual perception

    Czech Academy of Sciences Publication Activity Database

    Taddei-Ferretti, C.; Radilová, Jiřina; Musio, C.; Santillo, S.; Cibelli, E.; Cotugno, A.; Radil, Tomáš

    2008-01-01

    Roč. 1225, - (2008), s. 163-170 ISSN 0006-8993 Institutional research plan: CEZ:AV0Z50110509 Keywords : visual perception * figure reversal Subject RIV: FH - Neurology Impact factor: 2.494, year: 2008

  16. [Social behavior, musicality and visual perception in monogloid children (author's transl)].

    Science.gov (United States)

    Rabensteiner, B

    1975-01-01

    Forty-nine mongoloid and 48 non-mongol test persons of equivalent age and intelligence were selected and studied with respect to social behavior, speech disorders (observation of behavior), musicality and visual perception. There were significant differences in favor of the mongols with respect to social adaption. Speech disorders of all kinds occurred significantly more frequently in mongol children; stuttering was significantly more frequent in the boys. The mongol group did significantly better in the musicality test; the difference in the rhythmical part was highly significant. The average differences in the capacity for visual discrimination of colors, geometrical forms and the spatial relationship of geometrical forms were not significant.

  17. The changes in perception of visual illusions during long-term isolation

    Czech Academy of Sciences Publication Activity Database

    Šikl, Radovan; Šimeček, Michal; Lukavský, Jiří

    2009-01-01

    Roč. 2009, č. 38 (2009), s. 31-32 ISSN 0301-0066. [European Conference on Visual Perception. 24.08.2009-28.08.2009, Regensburg] R&D Projects: GA ČR GA406/09/2003 Institutional research plan: CEZ:AV0Z70250504 Keywords : long-term isolation * geometrical illusions * perspective Subject RIV: AN - Psychology http://www.perceptionweb.com/abstract.cgi?id=v090766

  18. Playing the electric light orchestra--how electrical stimulation of visual cortex elucidates the neural basis of perception.

    Science.gov (United States)

    Cicmil, Nela; Krug, Kristine

    2015-09-19

    Vision research has the potential to reveal fundamental mechanisms underlying sensory experience. Causal experimental approaches, such as electrical microstimulation, provide a unique opportunity to test the direct contributions of visual cortical neurons to perception and behaviour. But in spite of their importance, causal methods constitute a minority of the experiments used to investigate the visual cortex to date. We reconsider the function and organization of visual cortex according to results obtained from stimulation techniques, with a special emphasis on electrical stimulation of small groups of cells in awake subjects who can report their visual experience. We compare findings from humans and monkeys, striate and extrastriate cortex, and superficial versus deep cortical layers, and identify a number of revealing gaps in the 'causal map' of visual cortex. Integrating results from different methods and species, we provide a critical overview of the ways in which causal approaches have been used to further our understanding of circuitry, plasticity and information integration in visual cortex. Electrical stimulation not only elucidates the contributions of different visual areas to perception, but also contributes to our understanding of neuronal mechanisms underlying memory, attention and decision-making.

  19. Playing the electric light orchestra—how electrical stimulation of visual cortex elucidates the neural basis of perception

    Science.gov (United States)

    Cicmil, Nela; Krug, Kristine

    2015-01-01

    Vision research has the potential to reveal fundamental mechanisms underlying sensory experience. Causal experimental approaches, such as electrical microstimulation, provide a unique opportunity to test the direct contributions of visual cortical neurons to perception and behaviour. But in spite of their importance, causal methods constitute a minority of the experiments used to investigate the visual cortex to date. We reconsider the function and organization of visual cortex according to results obtained from stimulation techniques, with a special emphasis on electrical stimulation of small groups of cells in awake subjects who can report their visual experience. We compare findings from humans and monkeys, striate and extrastriate cortex, and superficial versus deep cortical layers, and identify a number of revealing gaps in the ‘causal map′ of visual cortex. Integrating results from different methods and species, we provide a critical overview of the ways in which causal approaches have been used to further our understanding of circuitry, plasticity and information integration in visual cortex. Electrical stimulation not only elucidates the contributions of different visual areas to perception, but also contributes to our understanding of neuronal mechanisms underlying memory, attention and decision-making. PMID:26240421

  20. Visual Context Modulates Action Perception In 10-Month-Old Infants

    OpenAIRE

    Noack, Hannes; Werkle-Bergner, Markus; Lindenberger, Ulman; Kopp, Franziska; Stadler, Waltraud; Springer, Anne; Bache, Cathleen

    2017-01-01

    Research on early action perception has documented infants' astounding abilities in tracking, predicting, and understanding other people's actions. Common interpretations of previous findings tend to generalize across a wide range of action stimuli and contexts. In this study, ten-month-old infants repeatedly watched a video of a same-aged crawling baby that was transiently occluded. The video was presented in alternation with videos displaying visually either dissimilar movements (i.e., dist...

  1. Is there a correlation between students' perceptions of their middle school science classroom learning environment and their classroom grades?

    Science.gov (United States)

    Snyder, Wayne

    The purpose of this study was to determine if the marking period grades of middle school science students are correlated with their perception of the classroom learning environment, and if so could such an indicator be used in feedback loops for ongoing classroom learning environment evaluation and evolution. The study examined 24 classrooms in three districts representing several different types of districts and a diverse student population. The independent variable was the students' perceptions of their classroom learning environment (CLE). This variable was represented by their responses on the WIHIC (What Is Happening In This Class) questionnaire. The dependent variable was the students' marking period grades. Background data about the students was included, and for further elaboration and clarification, qualitative data was collected through student and teacher interviews. Middle school science students in this study perceived as most positive those domains over which they have more locus of control. Perceptions showed some variance by gender, ethnicity, teacher/district, and socio-economic status when viewing the absolute values of the domain variables. The patterns of the results show consistency between groups. Direct correlation between questionnaire responses and student grades was not found to be significant except for a small significance with "Task Orientation". This unexpected lack of correlation may be explained by inconsistencies between grading schemes, inadequacies of the indicator instrument, and/or by the one-time administration of the variables. Analysis of the qualitative and quantitative data led to the conclusion that this instrument is picking up information, but that revisions in both the variables and in the process are needed. Grading schemes need to be decomposed, the instrument needs to be revised, and the process needs to be implemented as a series of regular feed-back loops.

  2. Global perception depends on coherent work of bilateral visual cortices: transcranial magnetic stimulation (TMS) studies.

    Science.gov (United States)

    Zhang, Xin; Han, ShiHui

    2007-08-01

    Previous research suggests that the right and left hemispheres dominate global and local perception of hierarchical patterns, respectively. The current work examined whether global perception of hierarchical stimuli requires coherent work of bilateral visual cortices using transcranial magnetic stimulation (TMS). Subjects discriminated global or local properties of compound letters in Experiment 1. Reaction times were recorded when single-pulse real TMS or sham TMS was delivered over the left or right visual cortex. While a global precedence effect (i.e., faster responses to global than local targets and stronger global-to-local interference than the reverse) was observed, TMS decreased global-to-local interference whereas increased local-to-global interference. Experiment 2 ruled out the possibility that the effects observed in Experiment 1 resulted from perceptual learning. Experiment 3 used compound shapes and observed TMS effect similar to that in Experiment 1. Moreover, TMS also slowed global RTs whereas speeded up local RTs in Experiment 3. Finally, the TMS effects observed in Experiments 1 and 3 did not differ between the conditions when TMS was applied over the left and right hemispheres. The results support a coherence hypothesis that global perception of compound stimuli depends upon the coherent work of bilateral visual cortices.

  3. Prevalence of high astigmatism, eyeglass wear, and poor visual acuity among Native American grade school children.

    Science.gov (United States)

    Harvey, Erin M; Dobson, Velma; Miller, Joseph M

    2006-04-01

    The purpose of this study was to examine the prevalence of astigmatism and poor visual acuity and rate of eyeglass wear in grade school children who are members of a Native American tribe reported to have a high prevalence of large amounts of astigmatism. Vision screening was conducted on 1,327 first through eighth grade children attending school on the Tohono O'odham Reservation. Noncycloplegic autorefraction was conducted on the right and left eye of each child using the Nikon Retinomax K+ autorefractor, and monocular recognition acuity was tested using ETDRS logarithm of the minimum angle of resolution (logMAR) letter charts. Tohono O'odham children had a high prevalence of high astigmatism (42% had > or = 1.00 D in the right or left eye) and the axis of astigmatism was uniformly with-the-rule. However, only a small percentage of children arrived at the vision screening wearing glasses, and the prevalence of poor visual acuity (20/40 or worse in either eye) was high (35%). There was a significant relation between amount of astigmatism and uncorrected visual acuity with each additional diopter of astigmatism resulting in an additional 1 logMAR line reduction in visual acuity. Uncorrected astigmatism and poor visual acuity are prevalent among Tohono O'odham children. The results highlight the importance of improving glasses-wearing compliance, determining barriers to receiving eye care, and initiating public education programs regarding the importance of early identification and correction of astigmatism in Tohono O'odham children.

  4. Visual Grading and Structural Properties Assessment of Large Cross-Section Pinus radiata D. Don Timber

    Directory of Open Access Journals (Sweden)

    Eva Hermoso Prieto

    2016-04-01

    Full Text Available The use of large cross-section timber for structural purposes has increased in Spain, and knowledge of its properties is strategically necessary. The Spanish visual strength-grading standard UNE 56544 (2011 efficiency applied to large cross-section structural timber was analyzed using a sample of 363 specimens of radiata pine (Pinus radiata D. Don. from the Basque Country and Catalonia, Spain. Different sizes were tested (80 × 120 × 2400 mm3, 150 × 250 × 5600 mm3, 150 × 250 × 4300 mm3, and 200 × 250 × 5000 mm3. Bending strength, modulus of elasticity, and density were obtained, and characteristic values were determined in order to assign strength class according to European standard EN 338 (2010. Knots and twists were the most relevant singularities for visual strength grading. It was concluded that large cross-section Spanish radiata pine timber was suitable for structures, and it was assigned to the C20 strength class.

  5. Non-Governmental Organization (NGO Libraries for The Visually Impaired in Nigeria: Alternative Format Use and Perception of Information Services

    Directory of Open Access Journals (Sweden)

    Adetoro, 'Niran

    2015-03-01

    Full Text Available Nigeria's non-government organization (NGO libraries for the visually impaired has over the years been at the forefront of information services provision to persons with visual impairment. This study adopted a survey research design to investigate use of alternative formats and perceptions of information services to the visually impaired, focusing on two purposively chosen NGO libraries for the visually impaired in Nigeria. Using a complete enumeration approach, data were gathered from 180 users of the libraries through the use of a structured questionnaire with a reliability score (${\\alpha}=0.74$. Data from 112 (62.2% of the 180 administered copies of a questionnaire that were retrieved were analysed. The study found that Braille materials had a high level of utilization ($\\bar{x}=4.46$ and were the most frequently utilized (90.9%. Perception of information services by the visually impaired was positive while use of alternative formats was significantly and positively related to users' perception of information services (r = .041; p < 0.05. The study recommends improved transcription and investment in alternative formats and in e-resources. It also recommends collaborations to widen access as well as constant evaluation of services.

  6. The perception of naturalness correlates with low-level visual features of environmental scenes.

    Directory of Open Access Journals (Sweden)

    Marc G Berman

    Full Text Available Previous research has shown that interacting with natural environments vs. more urban or built environments can have salubrious psychological effects, such as improvements in attention and memory. Even viewing pictures of nature vs. pictures of built environments can produce similar effects. A major question is: What is it about natural environments that produces these benefits? Problematically, there are many differing qualities between natural and urban environments, making it difficult to narrow down the dimensions of nature that may lead to these benefits. In this study, we set out to uncover visual features that related to individuals' perceptions of naturalness in images. We quantified naturalness in two ways: first, implicitly using a multidimensional scaling analysis and second, explicitly with direct naturalness ratings. Features that seemed most related to perceptions of naturalness were related to the density of contrast changes in the scene, the density of straight lines in the scene, the average color saturation in the scene and the average hue diversity in the scene. We then trained a machine-learning algorithm to predict whether a scene was perceived as being natural or not based on these low-level visual features and we could do so with 81% accuracy. As such we were able to reliably predict subjective perceptions of naturalness with objective low-level visual features. Our results can be used in future studies to determine if these features, which are related to naturalness, may also lead to the benefits attained from interacting with nature.

  7. Hemispheric differences in electrical and hemodynamic responses during hemifield visual stimulation with graded contrasts.

    Science.gov (United States)

    Si, Juanning; Zhang, Xin; Zhang, Yujin; Jiang, Tianzi

    2017-04-01

    A multimodal neuroimaging technique based on electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) was used with horizontal hemifield visual stimuli with graded contrasts to investigate the retinotopic mapping more fully as well as to explore hemispheric differences in neuronal activity, the hemodynamic response, and the neurovascular coupling relationship in the visual cortex. The fNIRS results showed the expected activation over the contralateral hemisphere for both the left and right hemifield visual stimulations. However, the EEG results presented a paradoxical lateralization, with the maximal response located over the ipsilateral hemisphere but with the polarity inversed components located over the contralateral hemisphere. Our results suggest that the polarity inversion as well as the latency advantage over the contralateral hemisphere cause the amplitude of the VEP over the contralateral hemisphere to be smaller than that over the ipsilateral hemisphere. Both the neuronal and hemodynamic responses changed logarithmically with the level of contrast in the hemifield visual stimulations. Moreover, the amplitudes and latencies of the visual evoked potentials (VEPs) were linearly correlated with the hemodynamic responses despite differences in the slopes.

  8. Ventral aspect of the visual form pathway is not critical for the perception of biological motion

    Science.gov (United States)

    Gilaie-Dotan, Sharon; Saygin, Ayse Pinar; Lorenzi, Lauren J.; Rees, Geraint; Behrmann, Marlene

    2015-01-01

    Identifying the movements of those around us is fundamental for many daily activities, such as recognizing actions, detecting predators, and interacting with others socially. A key question concerns the neurobiological substrates underlying biological motion perception. Although the ventral “form” visual cortex is standardly activated by biologically moving stimuli, whether these activations are functionally critical for biological motion perception or are epiphenomenal remains unknown. To address this question, we examined whether focal damage to regions of the ventral visual cortex, resulting in significant deficits in form perception, adversely affects biological motion perception. Six patients with damage to the ventral cortex were tested with sensitive point-light display paradigms. All patients were able to recognize unmasked point-light displays and their perceptual thresholds were not significantly different from those of three different control groups, one of which comprised brain-damaged patients with spared ventral cortex (n > 50). Importantly, these six patients performed significantly better than patients with damage to regions critical for biological motion perception. To assess the necessary contribution of different regions in the ventral pathway to biological motion perception, we complement the behavioral findings with a fine-grained comparison between the lesion location and extent, and the cortical regions standardly implicated in biological motion processing. This analysis revealed that the ventral aspects of the form pathway (e.g., fusiform regions, ventral extrastriate body area) are not critical for biological motion perception. We hypothesize that the role of these ventral regions is to provide enhanced multiview/posture representations of the moving person rather than to represent biological motion perception per se. PMID:25583504

  9. Effect of visual perception training combined with total nutrition meal sequential therapy on myopic amblyopia in preschool children

    Directory of Open Access Journals (Sweden)

    Hong Chen

    2017-12-01

    Full Text Available AIM: To observe the therapeutic effect of visual perception training combined with total nutrition meal sequential therapy in the treatment of myopic amblyopia. METHODS: Totally 73 children(135 eyeswith myopic amblyopia were divided into control group(36 cases, 67 eyesand treatment group(37 cases, 68 eyesaccording to random number table. The control group were treated with traditional spectaculars and grating covering combined with fine eyesight training; the treatment group were treated with visual perception training combined with total nutrient meal sequential therapy. The visual acuity, diopter and average diopter of two groups were compared before and after treatment at 3, 6mo and 1a. The curative effect of two groups of children was compared after 1a treatment. And the adverse reactions were recorded in two groups during the treatment period. The recurrence rate of amblyopia in 1a follow-up was compared between two groups. RESULTS: The difference of visual acuity between two groups was not significant at 3mo(P>0.05. The visual acuity of the treatment group was significantly higher than that of the control group at 6mo and 1a(PP>0.05, but the average annual refractive changes in the treatment group were significantly lower than that in the control group(PPPCONCLUSION: Visual perception training combined with total nutrition meal sequential therapy in the treatment of myopic amblyopia in preschool children can significantly improve patients' visual acuity, reduce the average annual diopter changes, improve the therapeutic effect, reduce the recurrence rate of amblyopia.

  10. Changes in Pain Modulation Occur Soon After Whiplash Trauma but are not Related to Altered Perception of Distorted Visual Feedback.

    Science.gov (United States)

    Daenen, Liesbeth; Nijs, Jo; Cras, Patrick; Wouters, Kristien; Roussel, Nathalie

    2014-09-01

    Widespread sensory hypersensitivity has been observed in acute whiplash associated disorders (WAD). Changes in descending pain modulation take part in central sensitization. However, endogenous pain modulation has never been investigated in acute WAD. Altered perception of distorted visual feedback has been observed in WAD. Both mechanisms (ie, pain modulation and perception of distorted visual feedback) may be different components of one integrated system orchestrated by the brain. This study evaluated conditioned pain modulation (CPM) in acute WAD. Secondly, we investigated whether changes in CPM are associated with altered perception of distorted visual feedback. Thirty patients with acute WAD, 35 patients with chronic WAD and 31 controls were subjected to an experiment evaluating CPM and a coordination task inducing visual mediated changes between sensory feedback and motor output. A significant CPM effect was observed in acute WAD (P = 0.012 and P = 0.006), which was significantly lower compared to controls (P = 0.004 and P = 0.020). No obvious differences in CPM were found between acute and chronic WAD (P = 0.098 and P = 0.041). Changes in CPM were unrelated to altered perception of distorted visual feedback (P > 0.01). Changes in CPM were observed in acute WAD, suggesting less efficient pain modulation. The results suggest that central pain and sensorimotor processing underlie distinctive mechanisms. © 2013 World Institute of Pain.

  11. Perception and psychological evaluation for visual and auditory environment based on the correlation mechanisms

    Science.gov (United States)

    Fujii, Kenji

    2002-06-01

    In this dissertation, the correlation mechanism in modeling the process in the visual perception is introduced. It has been well described that the correlation mechanism is effective for describing subjective attributes in auditory perception. The main result is that it is possible to apply the correlation mechanism to the process in temporal vision and spatial vision, as well as in audition. (1) The psychophysical experiment was performed on subjective flicker rates for complex waveforms. A remarkable result is that the phenomenon of missing fundamental is found in temporal vision as analogous to the auditory pitch perception. This implies the existence of correlation mechanism in visual system. (2) For spatial vision, the autocorrelation analysis provides useful measures for describing three primary perceptual properties of visual texture: contrast, coarseness, and regularity. Another experiment showed that the degree of regularity is a salient cue for texture preference judgment. (3) In addition, the autocorrelation function (ACF) and inter-aural cross-correlation function (IACF) were applied for analysis of the temporal and spatial properties of environmental noise. It was confirmed that the acoustical properties of aircraft noise and traffic noise are well described. These analyses provided useful parameters extracted from the ACF and IACF in assessing the subjective annoyance for noise. Thesis advisor: Yoichi Ando Copies of this thesis written in English can be obtained from Junko Atagi, 6813 Mosonou, Saijo-cho, Higashi-Hiroshima 739-0024, Japan. E-mail address: atagi\\@urban.ne.jp.

  12. Non-conscious visual cues related to affect and action alter perception of effort and endurance performance

    Directory of Open Access Journals (Sweden)

    Anthony William Blanchfield

    2014-12-01

    Full Text Available The psychobiological model of endurance performance proposes that endurance performance is determined by a decision-making process based on perception of effort and potential motivation. Recent research has reported that effort-based decision-making during cognitive tasks can be altered by non-conscious visual cues relating to affect and action. The effect of these non-conscious visual cues on effort and performance during physical tasks is however unknown. We report two experiments investigating the effect of subliminal priming with visual cues related to affect and action on perception of effort and endurance performance. In Experiment 1 thirteen individuals were subliminally primed with happy or sad faces as they cycled to exhaustion in a counterbalanced and randomized crossover design. A paired t-test (happy vs. sad faces revealed that individuals cycled for significantly longer (178 s, p = .04 when subliminally primed with happy faces. A 2 x 5 (condition x iso-time ANOVA also revealed a significant main effect of condition on rating of perceived exertion (RPE during the time to exhaustion (TTE test with lower RPE when subjects were subliminally primed with happy faces (p = .04. In Experiment 2, a single-subject randomization tests design found that subliminal priming with action words facilitated a significantly longer (399 s, p = .04 TTE in comparison to inaction words (p = .04. Like Experiment 1, this greater TTE was accompanied by a significantly lower RPE (p = .03. These experiments are the first to show that subliminal visual cues relating to affect and action can alter perception of effort and endurance performance. Non-conscious visual cues may therefore influence the effort-based decision-making process that is proposed to determine endurance performance. Accordingly, the findings raise notable implications for individuals who may encounter such visual cues during endurance competitions, training, or health related exercise.

  13. The prevalence of visual hallucinations in non-affective psychosis, and the role of perception and attention.

    Science.gov (United States)

    van Ommen, M M; van Beilen, M; Cornelissen, F W; Smid, H G O M; Knegtering, H; Aleman, A; van Laar, T

    2016-06-01

    Little is known about visual hallucinations (VH) in psychosis. We investigated the prevalence and the role of bottom-up and top-down processing in VH. The prevailing view is that VH are probably related to altered top-down processing, rather than to distorted bottom-up processing. Conversely, VH in Parkinson's disease are associated with impaired visual perception and attention, as proposed by the Perception and Attention Deficit (PAD) model. Auditory hallucinations (AH) in psychosis, however, are thought to be related to increased attention. Our retrospective database study included 1119 patients with non-affective psychosis and 586 controls. The Community Assessment of Psychic Experiences established the VH rate. Scores on visual perception tests [Degraded Facial Affect Recognition (DFAR), Benton Facial Recognition Task] and attention tests [Response Set-shifting Task, Continuous Performance Test-HQ (CPT-HQ)] were compared between 75 VH patients, 706 non-VH patients and 485 non-VH controls. The lifetime VH rate was 37%. The patient groups performed similarly on cognitive tasks; both groups showed worse perception (DFAR) than controls. Non-VH patients showed worse attention (CPT-HQ) than controls, whereas VH patients did not perform differently. We did not find significant VH-related impairments in bottom-up processing or direct top-down alterations. However, the results suggest a relatively spared attentional performance in VH patients, whereas face perception and processing speed were equally impaired in both patient groups relative to controls. This would match better with the increased attention hypothesis than with the PAD model. Our finding that VH frequently co-occur with AH may support an increased attention-induced 'hallucination proneness'.

  14. Enhanced visual awareness for morality and pajamas? Perception vs. memory in 'top-down' effects.

    Science.gov (United States)

    Firestone, Chaz; Scholl, Brian J

    2015-03-01

    A raft of prominent findings has revived the notion that higher-level cognitive factors such as desire, meaning, and moral relevance can directly affect what we see. For example, under conditions of brief presentation, morally relevant words reportedly "pop out" and are easier to identify than morally irrelevant words. Though such results purport to show that perception itself is sensitive to such factors, much of this research instead demonstrates effects on visual recognition--which necessarily involves not only visual processing per se, but also memory retrieval. Here we report three experiments which suggest that many alleged top-down effects of this sort are actually effects on 'back-end' memory rather than 'front-end' perception. In particular, the same methods used to demonstrate popout effects for supposedly privileged stimuli (such as morality-related words, e.g. "punishment" and "victim") also yield popout effects for unmotivated, superficial categories (such as fashion-related words, e.g. "pajamas" and "stiletto"). We conclude that such effects reduce to well-known memory processes (in this case, semantic priming) that do not involve morality, and have no implications for debates about whether higher-level factors influence perception. These case studies illustrate how it is critical to distinguish perception from memory in alleged 'top-down' effects. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Learning Visual Representations for Perception-Action Systems

    DEFF Research Database (Denmark)

    Piater, Justus; Jodogne, Sebastien; Detry, Renaud

    2011-01-01

    and RLJC, our second method learns structural object models for robust object detection and pose estimation by probabilistic inference. To these models, the method associates grasp experiences autonomously learned by trial and error. These experiences form a nonparametric representation of grasp success......We discuss vision as a sensory modality for systems that effect actions in response to perceptions. While the internal representations informed by vision may be arbitrarily complex, we argue that in many cases it is advantageous to link them rather directly to action via learned mappings....... These arguments are illustrated by two examples of our own work. First, our RLVC algorithm performs reinforcement learning directly on the visual input space. To make this very large space manageable, RLVC interleaves the reinforcement learner with a supervised classification algorithm that seeks to split...

  16. How does parents' visual perception of their child's weight status affect their feeding style?

    OpenAIRE

    Resul Yilmaz; Ünal Erkorkmaz; Mustafa Ozcetin; Erhan Karaaslan

    2013-01-01

    Introduction: Eating style is one of the prominent factors that determine energy intake. One of the influencing factors that determine parental feeding style is parental perception of the weight status of the child. Aim: The aim of this study is to evaluate the relationship between maternal visual perception of their children's weight status and their feeding style. Method: A cross-sectional survey was completed with only mother's of 380 preschool children with age of 5 to 7 (6.14 years). Vis...

  17. Effectiveness of Myocardial Contrast Echocardiography Quantitative Analysis during Adenosine Stress versus Visual Analysis before Percutaneous Therapy in Acute Coronary Pain: A Coronary Artery TIMI Grading Comparing Study

    Science.gov (United States)

    Yang, Lixia; Mu, Yuming; Quaglia, Luiz Augusto; Tang, Qi; Guan, Lina; Wang, Chunmei; Shih, Ming Chi

    2012-01-01

    The study aim was to compare two different stress echocardiography interpretation techniques based on the correlation with thrombosis in myocardial infarction (TIMI ) flow grading from acute coronary syndrome (ACS) patients. Forty-one patients with suspected ACS were studied before diagnostic coronary angiography with myocardial contrast echocardiography (MCE) at rest and at stress. The correlation of visual interpretation of MCE and TIMI flow grade was significant. The quantitative analysis (myocardial perfusion parameters: A, β, and A × β) and TIMI flow grade were significant. MCE visual interpretation and TIMI flow grade had a high degree of agreement, on diagnosing myocardial perfusion abnormality. If one considers TIMI flow grade <3 as abnormal, MCE visual interpretation at rest had 73.1% accuracy with 58.2% sensitivity and 84.2% specificity and at stress had 80.4% accuracy with 76.6% sensitivity and 83.3% specificity. The MCE quantitative analysis has better accuracy with 100% of agreement with different level of TIMI flow grading. MCE quantitative analysis at stress has showed a direct correlation with TIMI flow grade, more significant than the visual interpretation technique. Further studies could measure the clinical relevance of this more objective approach to managing acute coronary syndrome patient before percutaneous coronary intervention (PCI). PMID:22778555

  18. Visual exposure to large and small portion sizes and perceptions of portion size normality: Three experimental studies.

    Science.gov (United States)

    Robinson, Eric; Oldham, Melissa; Cuckson, Imogen; Brunstrom, Jeffrey M; Rogers, Peter J; Hardman, Charlotte A

    2016-03-01

    Portion sizes of many foods have increased in recent times. In three studies we examined the effect that repeated visual exposure to larger versus smaller food portion sizes has on perceptions of what constitutes a normal-sized food portion and measures of portion size selection. In studies 1 and 2 participants were visually exposed to images of large or small portions of spaghetti bolognese, before making evaluations about an image of an intermediate sized portion of the same food. In study 3 participants were exposed to images of large or small portions of a snack food before selecting a portion size of snack food to consume. Across the three studies, visual exposure to larger as opposed to smaller portion sizes resulted in participants considering a normal portion of food to be larger than a reference intermediate sized portion. In studies 1 and 2 visual exposure to larger portion sizes also increased the size of self-reported ideal meal size. In study 3 visual exposure to larger portion sizes of a snack food did not affect how much of that food participants subsequently served themselves and ate. Visual exposure to larger portion sizes may adjust visual perceptions of what constitutes a 'normal' sized portion. However, we did not find evidence that visual exposure to larger portions altered snack food intake. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Explaining academic-track boys' underachievement in language grades: Not a lack of aptitude but students' motivational beliefs and parents' perceptions?

    Science.gov (United States)

    Heyder, Anke; Kessels, Ursula; Steinmayr, Ricarda

    2017-06-01

    Boys earn lower grades in languages than girls. The expectancy-value model by Eccles et al. (, A series of books in psychology. Achievement and achievement motives. Psychological and sociological approaches, W.H. Freeman, San Francisco, CA, 76) is a comprehensive theoretical model for explaining gender differences in educational outcomes. In the past, most studies have focused on girls' disadvantage in math and science and on the role of the students' motivational beliefs. We aimed to explain boys' lower language grades by applying the expectancy-value model while taking into account students' motivational beliefs as well as their aptitude, prior achievement, and socializers' beliefs. In addition, we aimed at exploring the incremental contribution of each potential mediator. Five hundred and twenty German students (age M = 17 years; 58% female) and 374 parents (age M = 47 years). Student-reported ability self-concept (ASC) and task values, parents' perceptions of students' ability, students' prior achievement as reported by schools, and students' verbal intelligence test scores were all tested as mediators of the effect of gender on grades in German while controlling for parents' socioeconomic status. Single-mediator models and a multiple-mediator model were estimated using structural equation modelling. All variables proved to be relevant for explaining boys' underachievement in language grades. Whereas students' ASC, task values, prior achievement, and parents' perceptions mediated the gender effect, verbal intelligence was identified as a suppressor variable increasing the gender effect. Our results challenge the stereotypic belief that boys' lower grades are due to lower verbal aptitude. Rather, students' motivational beliefs and parents' perceptions seem critical factors. Implications for both future research and practice are discussed. © 2017 The British Psychological Society.

  20. Visually suboptimal bananas: How ripeness affects consumer expectation and perception.

    Science.gov (United States)

    Symmank, Claudia; Zahn, Susann; Rohm, Harald

    2018-01-01

    One reason for the significant amount of food that is wasted in developed countries is that consumers often expect visually suboptimal food as being less palatable. Using bananas as example, the objective of this study was to determine how appearance affects consumer overall liking, the rating of sensory attributes, purchase intention, and the intended use of bananas. The ripeness degree (RD) of the samples was adjusted to RD 5 (control) and RD 7 (more ripened, visually suboptimal). After preliminary experiments, a total of 233 participants were asked to judge their satisfaction with the intensity of sensory attributes that referred to flavor, taste, and texture using just-about-right scales. Subjects who received peeled samples were asked after tasting, whereas subjects who received unpeeled bananas judged expectation and, after peeling and tasting, perception. Expected overall liking and purchase intention were significantly lower for RD 7 bananas. Purchase intention was still significantly different between RD 5 and RD 7 after tasting, whereas no difference in overall liking was observed. Significant differences between RD 5 and RD 7 were observed when asking participants for their intended use of the bananas. Concerning the sensory attributes, penalty analysis revealed that only the firmness of the RD 7 bananas was still not just-about-right after tasting. The importance that consumers attribute to the shelf-life of food had a pronounced impact on purchase intention of bananas with different ripeness degree. In the case of suboptimal bananas, the results demonstrate a positive relationship between the sensory perception and overall liking and purchase intention. Convincing consumers that visually suboptimal food is still tasty is of high relevance for recommending different ways of communication. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Medical and pharmacy students' perceptions of the grading and assessment practices.

    Science.gov (United States)

    Kasanda, C D; Mitonga, K H; Veii, K; Zimba, R F

    2013-01-01

    Many students at the University of Namibia have frequently complained about ineffective assessment practices used at the institution. On many occasions, these complaints have not been substantiated with evidence of any kind. The purpose of this study was to obtain some empirical evidence that would ascertain undergraduate students' perceptions of the University of Namibia's grading and assessment practices. Using a structured scaled questionnaire, data were obtained from a representative sample of the University's undergraduate students studying for Medical and Pharmacy degrees. The questionnaire items covered matters related to students' experiences of assessment practices, feedback on assessment tasks, reliability and validity of assessment tools used by lecturers, efficacy of processes of administering examinations, perceptions of irregular and unfair assessment practices, impact of assessment regimes on students' cost of studies, motivation, morale, rate of progression in studies and graduation, the degree of compliance with assessment ethics and on academic quality assurance. According to the data reported in this article, the majority of the respondents perceived that the Schools of Medicine and Pharmacy at the University of Namibia applied assessment practices that yielded reliable and valid results. This was the case because most lecturers in the two schools used appropriate assessment tools and provided their students with prompt and informative feedback on the results of assignments, tests and examinations. In addition, most respondents reported that whereas examination procedures used in the two schools were efficient and effective, lecturers graded examination scripts fairly. These and other results are discussed in the article to communicate the message that the assessment procedures used in the Schools of Medicine and Pharmacy at the University of Namibia would promote effective learning and understanding amongst students as they were of high quality.

  2. MEDICAL AND PHARMACY STUDENTS’ PERCEPTIONS OF THE GRADING AND ASSESSMENT PRACTICES

    Directory of Open Access Journals (Sweden)

    Honoré eMITONGA KABWEBWE

    2013-07-01

    Full Text Available Many students at the University of Namibia have frequently complained about ineffective assessment practices used at the institution. On many occasions, these complaints have not been substantiated with evidence of any kind. The purpose of this study was to obtain some empirical evidence that would ascertain undergraduate students’ perceptions of the University of Namibia’s grading and assessment practices. Using a structured scaled questionnaire, data were obtained from a representative sample of the University’s undergraduate students studying for Medical and Pharmacy degrees. The questionnaire items covered matters related to students’ experiences of assessment practices, feedback on assessment tasks, reliability and validity of assessment tools used by lecturers, efficacy of processes of administering examinations, perceptions of irregular and unfair assessment practices, impact of assessment regimes on students’ cost of studies, motivation, morale, rate of progression in studies and graduation, the degree of compliance with assessment ethics and on academic quality assurance.According to the data reported in this article, the majority of the respondents perceived that the Schools of Medicine and Pharmacy at the University of Namibia applied assessment practices that yielded reliable and valid results. This was the case because most lecturers in the two schools used appropriate assessment tools and provided their students with prompt and informative feedback on the results of assignments, tests and examinations. In addition, most respondents reported that whereas examination procedures used in the two schools were efficient and effective, lecturers graded examination scripts fairly. These and other results are discussed in the article to communicate the message that the assessment procedures used in the Schools of Medicine and Pharmacy at the University of Namibia would promote effective learning and understanding amongst students

  3. The effect of two different visual presentation modalities on the narratives of mainstream grade 3 children.

    Science.gov (United States)

    Klop, D; Engelbrecht, L

    2013-12-01

    This study investigated whether a dynamic visual presentation method (a soundless animated video presentation) would elicit better narratives than a static visual presentation method (a wordless picture book). Twenty mainstream grade 3 children were randomly assigned to two groups and assessed with one of the visual presentation methods. Narrative performance was measured in terms of micro- and macrostructure variables. Microstructure variables included productivity (total number of words, total number of T-units), syntactic complexity (mean length of T-unit) and lexical diversity measures (number of different words). Macrostructure variables included episodic structure in terms of goal-attempt-outcome (GAO) sequences. Both visual presentation modalities elicited narratives of similar quantity and quality in terms of the micro- and macrostructure variables that were investigated. Animation of picture stimuli did not elicit better narratives than static picture stimuli.

  4. Using Japanese Onomatopoeias to Explore Perceptual Dimensions in Visual Material Perception.

    Science.gov (United States)

    Hanada, Mitsuhiko

    2016-01-28

    This study examined the perceptual dimensions of visual material properties. Photographs of 50 objects were presented to the participants, and they reported a suitable onomatopoeia (mimetic word) for describing the material of the object in each photograph, based on visual appearance. The participants' responses were collated into a contingency table of photographs × onomatopoeias. After removing some items from the table, correspondence analysis was applied to the contingency table, and a six-dimensional biplot was obtained. By rotating the axes to maximize sparseness of the coordinates for the items in the biplot, three meaningful perceptual dimensions were derived: wetness/stickiness, fluffiness/softness, and smoothness-roughness/gloss-dullness. Two additional possible dimensions were obtained: crumbliness and coldness. These dimensions, except gloss-dullness, were paid little attention to in vision science, though they were suggested as perceptual dimensions of tactile texture. This suggests that the perceptual dimensions that are considered to be primarily related to haptics are also important in visual material perception. © The Author(s) 2016.

  5. Self-estimation of physical ability in stepping over an obstacle is not mediated by visual height perception: a comparison between young and older adults.

    Science.gov (United States)

    Sakurai, Ryota; Fujiwara, Yoshinori; Ishihara, Masami; Yasunaga, Masashi; Ogawa, Susumu; Suzuki, Hiroyuki; Imanaka, Kuniyasu

    2017-07-01

    Older adults tend to overestimate their step-over ability. However, it is unclear as to whether this is caused by inaccurate self-estimation of physical ability or inaccurate perception of height. We, therefore, measured both visual height perception ability and self-estimation of step-over ability among young and older adults. Forty-seven older and 16 young adults performed a height perception test (HPT) and a step-over test (SOT). Participants visually judged the height of vertical bars from distances of 7 and 1 m away in the HPT, then self-estimated and, subsequently, actually performed a step-over action in the SOT. The results showed no significant difference between young and older adults in visual height perception. In the SOT, young adults tended to underestimate their step-over ability, whereas older adults either overestimated their abilities or underestimated them to a lesser extent than did the young adults. Moreover, visual height perception was not correlated with the self-estimation of step-over ability in both young and older adults. These results suggest that the self-overestimation of step-over ability which appeared in some healthy older adults may not be caused by the nature of visual height perception, but by other factor(s), such as the likely age-related nature of self-estimation of physical ability, per se.

  6. Spatial Visualization as Mediating between Mathematics Learning Strategy and Mathematics Achievement among 8th Grade Students

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    Rabab'h, Belal; Veloo, Arsaythamby

    2015-01-01

    Jordanian 8th grade students revealed low achievement in mathematics through four periods (1999, 2003, 2007 & 2011) of Trends in International Mathematics and Science Study (TIMSS). This study aimed to determine whether spatial visualization mediates the affect of Mathematics Learning Strategies (MLS) factors namely mathematics attitude,…

  7. Effective use of e-grading in the dental simulation clinic.

    Science.gov (United States)

    Morrow, Jay A; Pulido, M Teresa; Smith, P Bradford; McDaniel, Thomas F; Willcox, Austin B

    2014-06-01

    The purpose of this article is to describe the development and implementation of a grading software system, accessible from any platform, that engages today's generation of students and replaces paper grading. Set up at one U.S. dental school in an all-access, anytime (24/7) web-based program accessed through tablets, the software allows for a comparison between students' self-grading and instructor grading. This comparison facilitates student-faculty interaction, promoting discussion and student learning. The software can also be used for practical examination grading in which blinded grading between instructors is possible. The data gathered can produce descriptive reports students can draw upon to encourage self-learning and guided learning, propelling students to a better understanding of critical principles as they progress through multiple psychomotor skill sets. Other reports generated by the software allow for instructor calibration, exporting of grades directly into the university grading report system, and visual analysis of trends within each class. In a post-course survey, students (56 percent response rate) and faculty (79 percent response rate) agreed that the electronic grading was more efficient and allowed more time for faculty-student interaction than the previous grading system, thus creating an environment more conducive to learning. Overall, the software has improved students' perception of enhanced kinetic skills, while facilitating administration of preclinical projects and practical examinations.

  8. Large Scale Functional Brain Networks Underlying Temporal Integration of Audio-Visual Speech Perception: An EEG Study.

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    Kumar, G Vinodh; Halder, Tamesh; Jaiswal, Amit K; Mukherjee, Abhishek; Roy, Dipanjan; Banerjee, Arpan

    2016-01-01

    Observable lip movements of the speaker influence perception of auditory speech. A classical example of this influence is reported by listeners who perceive an illusory (cross-modal) speech sound (McGurk-effect) when presented with incongruent audio-visual (AV) speech stimuli. Recent neuroimaging studies of AV speech perception accentuate the role of frontal, parietal, and the integrative brain sites in the vicinity of the superior temporal sulcus (STS) for multisensory speech perception. However, if and how does the network across the whole brain participates during multisensory perception processing remains an open question. We posit that a large-scale functional connectivity among the neural population situated in distributed brain sites may provide valuable insights involved in processing and fusing of AV speech. Varying the psychophysical parameters in tandem with electroencephalogram (EEG) recordings, we exploited the trial-by-trial perceptual variability of incongruent audio-visual (AV) speech stimuli to identify the characteristics of the large-scale cortical network that facilitates multisensory perception during synchronous and asynchronous AV speech. We evaluated the spectral landscape of EEG signals during multisensory speech perception at varying AV lags. Functional connectivity dynamics for all sensor pairs was computed using the time-frequency global coherence, the vector sum of pairwise coherence changes over time. During synchronous AV speech, we observed enhanced global gamma-band coherence and decreased alpha and beta-band coherence underlying cross-modal (illusory) perception compared to unisensory perception around a temporal window of 300-600 ms following onset of stimuli. During asynchronous speech stimuli, a global broadband coherence was observed during cross-modal perception at earlier times along with pre-stimulus decreases of lower frequency power, e.g., alpha rhythms for positive AV lags and theta rhythms for negative AV lags. Thus, our

  9. Visual perception of axes of head rotation

    Science.gov (United States)

    Arnoldussen, D. M.; Goossens, J.; van den Berg, A. V.

    2013-01-01

    Registration of ego-motion is important to accurately navigate through space. Movements of the head and eye relative to space are registered through the vestibular system and optical flow, respectively. Here, we address three questions concerning the visual registration of self-rotation. (1) Eye-in-head movements provide a link between the motion signals received by sensors in the moving eye and sensors in the moving head. How are these signals combined into an ego-rotation percept? We combined optic flow of simulated forward and rotational motion of the eye with different levels of eye-in-head rotation for a stationary head. We dissociated simulated gaze rotation and head rotation by different levels of eye-in-head pursuit. We found that perceived rotation matches simulated head- not gaze-rotation. This rejects a model for perceived self-rotation that relies on the rotation of the gaze line. Rather, eye-in-head signals serve to transform the optic flow's rotation information, that specifies rotation of the scene relative to the eye, into a rotation relative to the head. This suggests that transformed visual self-rotation signals may combine with vestibular signals. (2) Do transformed visual self-rotation signals reflect the arrangement of the semi-circular canals (SCC)? Previously, we found sub-regions within MST and V6+ that respond to the speed of the simulated head rotation. Here, we re-analyzed those Blood oxygenated level-dependent (BOLD) signals for the presence of a spatial dissociation related to the axes of visually simulated head rotation, such as have been found in sub-cortical regions of various animals. Contrary, we found a rather uniform BOLD response to simulated rotation along the three SCC axes. (3) We investigated if subject's sensitivity to the direction of the head rotation axis shows SCC axes specifcity. We found that sensitivity to head rotation is rather uniformly distributed, suggesting that in human cortex, visuo-vestibular integration is

  10. Visual perception of axes of head rotation

    Directory of Open Access Journals (Sweden)

    David Mattijs Arnoldussen

    2013-02-01

    Full Text Available Registration of ego-motion is important to accurately navigate through space. Movements of the head and eye relative to space are registered through the vestibular system and optical flow, respectively. Here, we address three questions concerning the visual registration of self-rotation. 1. Eye-in-head movements provide a link between the motion signals received by sensors in the moving eye and sensors in the moving head. How are these signals combined into an ego-rotation percept? We combined optic flow of simulated forward and rotational motion of the eye with different levels of eye-in-head rotation for a stationary head. We dissociated simulated gaze rotation and head rotation by different levels of eye-in-head pursuit.We found that perceived rotation matches simulated head- not gaze-rotation. This rejects a model for perceived self-rotation that relies on the rotation of the gaze line. Rather, eye-in-head signals serve to transform the optic flow’s rotation information, that specifies rotation of the scene relative to the eye, into a rotation relative to the head. This suggests that transformed visual self-rotation signals may combine with vestibular signals.2. Do transformed visual self-rotation signals reflect the arrangement of the semicircular canals (SCC? Previously, we found sub-regions within MST and V6+ that respond to the speed of the simulated head rotation. Here, we re-analyzed those BOLD signals for the presence of a spatial dissociation related to the axes of visually simulated head rotation, such as have been found in sub-cortical regions of various animals. Contrary, we found a rather uniform BOLD response to simulated rotation along the three SCC axes.3. We investigated if subject’s sensitivity to the direction of the head rotation axis shows SCC axes specifcity. We found that sensitivity to head rotation is rather uniformly distributed, suggesting that in human cortex, visuo-vestibular integration is not arranged into

  11. Human fMRI reveals that delayed action re-recruits visual perception.

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    Singhal, Anthony; Monaco, Simona; Kaufman, Liam D; Culham, Jody C

    2013-01-01

    Behavioral and neuropsychological research suggests that delayed actions rely on different neural substrates than immediate actions; however, the specific brain areas implicated in the two types of actions remain unknown. We used functional magnetic resonance imaging (fMRI) to measure human brain activation during delayed grasping and reaching. Specifically, we examined activation during visual stimulation and action execution separated by a 18-s delay interval in which subjects had to remember an intended action toward the remembered object. The long delay interval enabled us to unambiguously distinguish visual, memory-related, and action responses. Most strikingly, we observed reactivation of the lateral occipital complex (LOC), a ventral-stream area implicated in visual object recognition, and early visual cortex (EVC) at the time of action. Importantly this reactivation was observed even though participants remained in complete darkness with no visual stimulation at the time of the action. Moreover, within EVC, higher activation was observed for grasping than reaching during both vision and action execution. Areas in the dorsal visual stream were activated during action execution as expected and, for some, also during vision. Several areas, including the anterior intraparietal sulcus (aIPS), dorsal premotor cortex (PMd), primary motor cortex (M1) and the supplementary motor area (SMA), showed sustained activation during the delay phase. We propose that during delayed actions, dorsal-stream areas plan and maintain coarse action goals; however, at the time of execution, motor programming requires re-recruitment of detailed visual information about the object through reactivation of (1) ventral-stream areas involved in object perception and (2) early visual areas that contain richly detailed visual representations, particularly for grasping.

  12. Human fMRI reveals that delayed action re-recruits visual perception.

    Directory of Open Access Journals (Sweden)

    Anthony Singhal

    Full Text Available Behavioral and neuropsychological research suggests that delayed actions rely on different neural substrates than immediate actions; however, the specific brain areas implicated in the two types of actions remain unknown. We used functional magnetic resonance imaging (fMRI to measure human brain activation during delayed grasping and reaching. Specifically, we examined activation during visual stimulation and action execution separated by a 18-s delay interval in which subjects had to remember an intended action toward the remembered object. The long delay interval enabled us to unambiguously distinguish visual, memory-related, and action responses. Most strikingly, we observed reactivation of the lateral occipital complex (LOC, a ventral-stream area implicated in visual object recognition, and early visual cortex (EVC at the time of action. Importantly this reactivation was observed even though participants remained in complete darkness with no visual stimulation at the time of the action. Moreover, within EVC, higher activation was observed for grasping than reaching during both vision and action execution. Areas in the dorsal visual stream were activated during action execution as expected and, for some, also during vision. Several areas, including the anterior intraparietal sulcus (aIPS, dorsal premotor cortex (PMd, primary motor cortex (M1 and the supplementary motor area (SMA, showed sustained activation during the delay phase. We propose that during delayed actions, dorsal-stream areas plan and maintain coarse action goals; however, at the time of execution, motor programming requires re-recruitment of detailed visual information about the object through reactivation of (1 ventral-stream areas involved in object perception and (2 early visual areas that contain richly detailed visual representations, particularly for grasping.

  13. Visual adaptation of the perception of "life": animacy is a basic perceptual dimension of faces.

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    Koldewyn, Kami; Hanus, Patricia; Balas, Benjamin

    2014-08-01

    One critical component of understanding another's mind is the perception of "life" in a face. However, little is known about the cognitive and neural mechanisms underlying this perception of animacy. Here, using a visual adaptation paradigm, we ask whether face animacy is (1) a basic dimension of face perception and (2) supported by a common neural mechanism across distinct face categories defined by age and species. Observers rated the perceived animacy of adult human faces before and after adaptation to (1) adult faces, (2) child faces, and (3) dog faces. When testing the perception of animacy in human faces, we found significant adaptation to both adult and child faces, but not dog faces. We did, however, find significant adaptation when morphed dog images and dog adaptors were used. Thus, animacy perception in faces appears to be a basic dimension of face perception that is species specific but not constrained by age categories.

  14. Effect of drivers' age and push button locations on visual time off road, steering wheel deviation and safety perception.

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    Dukic, T; Hanson, L; Falkmer, T

    2006-01-15

    The study examined the effects of manual control locations on two groups of randomly selected young and old drivers in relation to visual time off road, steering wheel deviation and safety perception. Measures of visual time off road, steering wheel deviations and safety perception were performed with young and old drivers during real traffic. The results showed an effect of both driver's age and button location on the dependent variables. Older drivers spent longer visual time off road when pushing the buttons and had larger steering wheel deviations. Moreover, the greater the eccentricity between the normal line of sight and the button locations, the longer the visual time off road and the larger the steering wheel deviations. No interaction effect between button location and age was found with regard to visual time off road. Button location had an effect on perceived safety: the further away from the normal line of sight the lower the rating.

  15. Visual perceptions of male obesity: a cross-cultural study examining male and female lay perceptions of obesity in Caucasian males.

    Science.gov (United States)

    Robinson, Eric; Hogenkamp, Pleunie S

    2015-05-16

    Obesity is now common and this may have altered visual perceptions of what constitutes a 'normal' and therefore healthy weight. The present study examined cross-cultural differences in male and female participants' ability to visually identify the weight status of photographed Caucasian males. Five hundred and fifty three male and female young adults from the US (high obesity prevalence), UK and Sweden (lower obesity prevalence) participated in an online study. Participants judged the weight status of a series of photographed healthy weight, overweight and obese (class I) Caucasian males and rated the extent to which they believed each male should consider losing weight. There was a strong tendency for both male and female participants to underestimate the weight status of the photographed overweight and obese males. Photographed males were frequently perceived as being of healthier weight than they actually were. Some modest cross-cultural differences were also observed; US participants were worse at recognising obesity than UK participants (p cross-cultural differences were observed for perceptions or attitudes towards the photographed healthy weight or overweight males. The weight status of overweight and obese (class I) Caucasian males is underestimated when judged by males and females using visual information alone. This study provides initial evidence of modest cross-cultural differences in attitudes toward, and the ability to recognise, obesity in Caucasian males.

  16. Examining Pre-Kindergarten-Grade 8 Teacher Practices and Perceptions Regarding Using Facebook and Twitter for Parent-Teacher Communication

    Science.gov (United States)

    Gruber, Heidi

    2016-01-01

    The purpose of this quantitative, descriptive, survey research was to examine pre-Kindergarten- Grade 8 teacher's perceptions regarding their preparedness, propensity, and felt value of using Facebook and Twitter for parent-teacher communication. The 38 participants completed the Teacher Presurvey, followed by an online instructional intervention,…

  17. A review of visual perception mechanisms that regulate rapid adaptive camouflage in cuttlefish.

    Science.gov (United States)

    Chiao, Chuan-Chin; Chubb, Charles; Hanlon, Roger T

    2015-09-01

    We review recent research on the visual mechanisms of rapid adaptive camouflage in cuttlefish. These neurophysiologically complex marine invertebrates can camouflage themselves against almost any background, yet their ability to quickly (0.5-2 s) alter their body patterns on different visual backgrounds poses a vexing challenge: how to pick the correct body pattern amongst their repertoire. The ability of cuttlefish to change appropriately requires a visual system that can rapidly assess complex visual scenes and produce the motor responses-the neurally controlled body patterns-that achieve camouflage. Using specifically designed visual backgrounds and assessing the corresponding body patterns quantitatively, we and others have uncovered several aspects of scene variation that are important in regulating cuttlefish patterning responses. These include spatial scale of background pattern, background intensity, background contrast, object edge properties, object contrast polarity, object depth, and the presence of 3D objects. Moreover, arm postures and skin papillae are also regulated visually for additional aspects of concealment. By integrating these visual cues, cuttlefish are able to rapidly select appropriate body patterns for concealment throughout diverse natural environments. This sensorimotor approach of studying cuttlefish camouflage thus provides unique insights into the mechanisms of visual perception in an invertebrate image-forming eye.

  18. Making Memories: The Development of Long-Term Visual Knowledge in Children with Visual Agnosia

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    Tiziana Metitieri

    2013-01-01

    Full Text Available There are few reports about the effects of perinatal acquired brain lesions on the development of visual perception. These studies demonstrate nonseverely impaired visual-spatial abilities and preserved visual memory. Longitudinal data analyzing the effects of compromised perceptions on long-term visual knowledge in agnosics are limited to lesions having occurred in adulthood. The study of children with focal lesions of the visual pathways provides a unique opportunity to assess the development of visual memory when perceptual input is degraded. We assessed visual recognition and visual memory in three children with lesions to the visual cortex having occurred in early infancy. We then explored the time course of visual memory impairment in two of them at 2 years and 3.7 years from the initial assessment. All children exhibited apperceptive visual agnosia and visual memory impairment. We observed a longitudinal improvement of visual memory modulated by the structural properties of objects. Our findings indicate that processing of degraded perceptions from birth results in impoverished memories. The dynamic interaction between perception and memory during development might modulate the long-term construction of visual representations, resulting in less severe impairment.

  19. Making memories: the development of long-term visual knowledge in children with visual agnosia.

    Science.gov (United States)

    Metitieri, Tiziana; Barba, Carmen; Pellacani, Simona; Viggiano, Maria Pia; Guerrini, Renzo

    2013-01-01

    There are few reports about the effects of perinatal acquired brain lesions on the development of visual perception. These studies demonstrate nonseverely impaired visual-spatial abilities and preserved visual memory. Longitudinal data analyzing the effects of compromised perceptions on long-term visual knowledge in agnosics are limited to lesions having occurred in adulthood. The study of children with focal lesions of the visual pathways provides a unique opportunity to assess the development of visual memory when perceptual input is degraded. We assessed visual recognition and visual memory in three children with lesions to the visual cortex having occurred in early infancy. We then explored the time course of visual memory impairment in two of them at 2  years and 3.7  years from the initial assessment. All children exhibited apperceptive visual agnosia and visual memory impairment. We observed a longitudinal improvement of visual memory modulated by the structural properties of objects. Our findings indicate that processing of degraded perceptions from birth results in impoverished memories. The dynamic interaction between perception and memory during development might modulate the long-term construction of visual representations, resulting in less severe impairment.

  20. Visual masking and the dynamics of human perception, cognition, and consciousness A century of progress, a contemporary synthesis, and future directions.

    Science.gov (United States)

    Ansorge, Ulrich; Francis, Gregory; Herzog, Michael H; Oğmen, Haluk

    2008-07-15

    The 1990s, the "decade of the brain," witnessed major advances in the study of visual perception, cognition, and consciousness. Impressive techniques in neurophysiology, neuroanatomy, neuropsychology, electrophysiology, psychophysics and brain-imaging were developed to address how the nervous system transforms and represents visual inputs. Many of these advances have dealt with the steady-state properties of processing. To complement this "steady-state approach," more recent research emphasized the importance of dynamic aspects of visual processing. Visual masking has been a paradigm of choice for more than a century when it comes to the study of dynamic vision. A recent workshop (http://lpsy.epfl.ch/VMworkshop/), held in Delmenhorst, Germany, brought together an international group of researchers to present state-of-the-art research on dynamic visual processing with a focus on visual masking. This special issue presents peer-reviewed contributions by the workshop participants and provides a contemporary synthesis of how visual masking can inform the dynamics of human perception, cognition, and consciousness.

  1. Influence of optical properties of esthetic brackets (color, translucence, and fluorescence) on visual perception.

    Science.gov (United States)

    Lopes Filho, Hibernon; Maia, Lúcio E G; Araújo, Marcus Vinicius A; Ruellas, Antônio Carlos O

    2012-04-01

    The aims of this study were to evaluate the optical properties of esthetic brackets and determine their influence on visual perception. Eighty esthetic brackets of 16 commercial brands were tested. The color and translucency of the brackets, as well as the color of the maxillary central incisors of 40 subjects, were measured with a spectrophotometer. The fluorescence of the brackets was determined by duly calibrated appraisers. The color differences between the brands of brackets and the teeth were calculated. Data were analyzed by using 1-way analysis of variance; the Scheffé multiple comparison test was used to establish the difference between brands of brackets, (α = 0.05). The color parameters L ∗ a ∗ b ∗ of nontranslucent brackets ranged from 49.4 to 86.0, -1.6 to 3.0, and 1.9 to 14.6, respectively. The direct transmission of light ranged from 0.0% to 38.8% transmittance. No bracket showed fluorescence. The color and translucency, as well as the color difference, of the brackets were influenced by brand (P perception; translucent brackets and the nontranslucent InVu (TP Orthodontics, LaPorte, Ind) brackets were less visually perceptible. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  2. Visual working memory contents bias ambiguous structure from motion perception.

    Directory of Open Access Journals (Sweden)

    Lisa Scocchia

    Full Text Available The way we perceive the visual world depends crucially on the state of the observer. In the present study we show that what we are holding in working memory (WM can bias the way we perceive ambiguous structure from motion stimuli. Holding in memory the percept of an unambiguously rotating sphere influenced the perceived direction of motion of an ambiguously rotating sphere presented shortly thereafter. In particular, we found a systematic difference between congruent dominance periods where the perceived direction of the ambiguous stimulus corresponded to the direction of the unambiguous one and incongruent dominance periods. Congruent dominance periods were more frequent when participants memorized the speed of the unambiguous sphere for delayed discrimination than when they performed an immediate judgment on a change in its speed. The analysis of dominance time-course showed that a sustained tendency to perceive the same direction of motion as the prior stimulus emerged only in the WM condition, whereas in the attention condition perceptual dominance dropped to chance levels at the end of the trial. The results are explained in terms of a direct involvement of early visual areas in the active representation of visual motion in WM.

  3. Altered visual perception in long-term ecstasy (MDMA) users.

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    White, Claire; Brown, John; Edwards, Mark

    2013-09-01

    The present study investigated the long-term consequences of ecstasy use on visual processes thought to reflect serotonergic functions in the occipital lobe. Evidence indicates that the main psychoactive ingredient in ecstasy (methylendioxymethamphetamine) causes long-term changes to the serotonin system in human users. Previous research has found that amphetamine-abstinent ecstasy users have disrupted visual processing in the occipital lobe which relies on serotonin, with researchers concluding that ecstasy broadens orientation tuning bandwidths. However, other processes may have accounted for these results. The aim of the present research was to determine if amphetamine-abstinent ecstasy users have changes in occipital lobe functioning, as revealed by two studies: a masking study that directly measured the width of orientation tuning bandwidths and a contour integration task that measured the strength of long-range connections in the visual cortex of drug users compared to controls. Participants were compared on the width of orientation tuning bandwidths (26 controls, 12 ecstasy users, 10 ecstasy + amphetamine users) and the strength of long-range connections (38 controls, 15 ecstasy user, 12 ecstasy + amphetamine users) in the occipital lobe. Amphetamine-abstinent ecstasy users had significantly broader orientation tuning bandwidths than controls and significantly lower contour detection thresholds (CDTs), indicating worse performance on the task, than both controls and ecstasy + amphetamine users. These results extend on previous research, which is consistent with the proposal that ecstasy may damage the serotonin system, resulting in behavioral changes on tests of visual perception processes which are thought to reflect serotonergic functions in the occipital lobe.

  4. Perceptions of 9th and 10th Grade Students on How Their Environment, Cognition, and Behavior Motivate Them in Algebra and Geometry Courses

    Science.gov (United States)

    Harootunian, Alen

    2012-01-01

    In this study, relationships were examined between students' perception of their cognition, behavior, environment, and motivation. The purpose of the research study was to explore the extent to which 9th and 10th grade students' perception of environment, cognition, and behavior can predict their motivation in Algebra and Geometry courses. A…

  5. Optical Associative Processors For Visual Perception"

    Science.gov (United States)

    Casasent, David; Telfer, Brian

    1988-05-01

    We consider various associative processor modifications required to allow these systems to be used for visual perception, scene analysis, and object recognition. For these applications, decisions on the class of the objects present in the input image are required and thus heteroassociative memories are necessary (rather than the autoassociative memories that have been given most attention). We analyze the performance of both associative processors and note that there is considerable difference between heteroassociative and autoassociative memories. We describe associative processors suitable for realizing functions such as: distortion invariance (using linear discriminant function memory synthesis techniques), noise and image processing performance (using autoassociative memories in cascade with with a heteroassociative processor and with a finite number of autoassociative memory iterations employed), shift invariance (achieved through the use of associative processors operating on feature space data), and the analysis of multiple objects in high noise (which is achieved using associative processing of the output from symbolic correlators). We detail and provide initial demonstrations of the use of associative processors operating on iconic, feature space and symbolic data, as well as adaptive associative processors.

  6. A dual systems account of visual perception: Predicting candy consumption from distance estimates.

    Science.gov (United States)

    Krpan, Dario; Schnall, Simone

    2017-04-01

    A substantial amount of evidence shows that visual perception is influenced by forces that control human actions, ranging from motivation to physiological potential. However, studies have not yet provided convincing evidence that perception itself is directly involved in everyday behaviors such as eating. We suggest that this issue can be resolved by employing the dual systems account of human behavior. We tested the link between perceived distance to candies and their consumption for participants who were tired or depleted (impulsive system), versus those who were not (reflective system). Perception predicted eating only when participants were tired (Experiment 1) or depleted (Experiments 2 and 3). In contrast, a rational determinant of behavior-eating restraint towards candies-predicted eating for non-depleted individuals (Experiment 2). Finally, Experiment 3 established that perceived distance was correlated with participants' self-reported motivation to consume candies. Overall, these findings suggest that the dynamics between perception and behavior depend on the interplay of the two behavioral systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Perceptions and Concerns about Inclusive Education among Students with Visual Impairments in Lagos, Nigeria

    Science.gov (United States)

    Brydges, Colton; Mkandawire, Paul

    2017-01-01

    This article examines the perceptions of inclusive education in Lagos, Nigeria, based upon in-depth interviews conducted with students with visual impairments during the month of July 2013. The results and discussions are situated within critical disability theory. Despite decades of inclusive education policies, the findings of the study show…

  8. Atypical audio-visual speech perception and McGurk effects in children with specific language impairment.

    Science.gov (United States)

    Leybaert, Jacqueline; Macchi, Lucie; Huyse, Aurélie; Champoux, François; Bayard, Clémence; Colin, Cécile; Berthommier, Frédéric

    2014-01-01

    Audiovisual speech perception of children with specific language impairment (SLI) and children with typical language development (TLD) was compared in two experiments using /aCa/ syllables presented in the context of a masking release paradigm. Children had to repeat syllables presented in auditory alone, visual alone (speechreading), audiovisual congruent and incongruent (McGurk) conditions. Stimuli were masked by either stationary (ST) or amplitude modulated (AM) noise. Although children with SLI were less accurate in auditory and audiovisual speech perception, they showed similar auditory masking release effect than children with TLD. Children with SLI also had less correct responses in speechreading than children with TLD, indicating impairment in phonemic processing of visual speech information. In response to McGurk stimuli, children with TLD showed more fusions in AM noise than in ST noise, a consequence of the auditory masking release effect and of the influence of visual information. Children with SLI did not show this effect systematically, suggesting they were less influenced by visual speech. However, when the visual cues were easily identified, the profile of responses to McGurk stimuli was similar in both groups, suggesting that children with SLI do not suffer from an impairment of audiovisual integration. An analysis of percent of information transmitted revealed a deficit in the children with SLI, particularly for the place of articulation feature. Taken together, the data support the hypothesis of an intact peripheral processing of auditory speech information, coupled with a supra modal deficit of phonemic categorization in children with SLI. Clinical implications are discussed.

  9. Blind jealousy? Romantic insecurity increases emotion-induced failures of visual perception.

    Science.gov (United States)

    Most, Steven B; Laurenceau, Jean-Philippe; Graber, Elana; Belcher, Amber; Smith, C Veronica

    2010-04-01

    Does the influence of close relationships pervade so deeply as to impact visual awareness? Results from two experiments involving heterosexual romantic couples suggest that they do. Female partners from each couple performed a rapid detection task where negative emotional distractors typically disrupt visual awareness of subsequent targets; at the same time, their male partners rated attractiveness first of landscapes, then of photos of other women. At the end of both experiments, the degree to which female partners indicated uneasiness about their male partner looking at and rating other women correlated significantly with the degree to which negative emotional distractors had disrupted their target perception during that time. This relationship was robust even when controlling for individual differences in baseline performance. Thus, emotions elicited by social contexts appear to wield power even at the level of perceptual processing. Copyright 2010 APA, all rights reserved.

  10. Graded representations of emotional expressions in the left superior temporal sulcus

    Directory of Open Access Journals (Sweden)

    Christopher P Said

    2010-03-01

    Full Text Available Perceptual categorization is a fundamental cognitive process that gives meaning to an often graded sensory environment. Previous research has subdivided the visual pathway into posterior regions that processes the physical properties of a stimulus, and frontal regions that process more abstract properties such as category information. The superior temporal sulcus (STS is known to be involved in face and emotion perception, but the nature of its processing remains unknown. Here, we used targeted fMRI measurements of the STS to investigate whether its representations of facial expressions are categorical or noncategorical. Multivoxel pattern analysis showed that even though subjects were performing a categorization task, the left STS contained graded, noncategorical representations. In the right STS, representations showed evidence for both stimulus-related gradations and a categorical boundary.

  11. Visual grading characteristics and ordinal regression analysis during optimisation of CT head examinations.

    Science.gov (United States)

    Zarb, Francis; McEntee, Mark F; Rainford, Louise

    2015-06-01

    To evaluate visual grading characteristics (VGC) and ordinal regression analysis during head CT optimisation as a potential alternative to visual grading assessment (VGA), traditionally employed to score anatomical visualisation. Patient images (n = 66) were obtained using current and optimised imaging protocols from two CT suites: a 16-slice scanner at the national Maltese centre for trauma and a 64-slice scanner in a private centre. Local resident radiologists (n = 6) performed VGA followed by VGC and ordinal regression analysis. VGC alone indicated that optimised protocols had similar image quality as current protocols. Ordinal logistic regression analysis provided an in-depth evaluation, criterion by criterion allowing the selective implementation of the protocols. The local radiology review panel supported the implementation of optimised protocols for brain CT examinations (including trauma) in one centre, achieving radiation dose reductions ranging from 24 % to 36 %. In the second centre a 29 % reduction in radiation dose was achieved for follow-up cases. The combined use of VGC and ordinal logistic regression analysis led to clinical decisions being taken on the implementation of the optimised protocols. This improved method of image quality analysis provided the evidence to support imaging protocol optimisation, resulting in significant radiation dose savings. • There is need for scientifically based image quality evaluation during CT optimisation. • VGC and ordinal regression analysis in combination led to better informed clinical decisions. • VGC and ordinal regression analysis led to dose reductions without compromising diagnostic efficacy.

  12. Association of Grade Configuration with School Climate for 7th and 8th Grade Students

    Science.gov (United States)

    Malone, Marisa; Cornell, Dewey; Shukla, Kathan

    2017-01-01

    Educational authorities have questioned whether middle schools provide the best school climate for 7th and 8th grade students, and proposed that other grade configurations such as K-8th grade schools may provide a better learning environment. The purpose of this study was to compare 7th and 8th grade students' perceptions of 4 key features of…

  13. Pairwise comparisons and visual perceptions of equal area polygons.

    Science.gov (United States)

    Adamic, P; Babiy, V; Janicki, R; Kakiashvili, T; Koczkodaj, W W; Tadeusiewicz, R

    2009-02-01

    The number of studies related to visual perception has been plentiful in recent years. Participants rated the areas of five randomly generated shapes of equal area, using a reference unit area that was displayed together with the shapes. Respondents were 179 university students from Canada and Poland. The average error estimated by respondents using the unit square was 25.75%. The error was substantially decreased to 5.51% when the shapes were compared to one another in pairs. This gain of 20.24% for this two-dimensional experiment was substantially better than the 11.78% gain reported in the previous one-dimensional experiments. This is the first statistically sound two-dimensional experiment demonstrating that pairwise comparisons improve accuracy.

  14. Automated visual grading of grain kernels by machine vision

    Science.gov (United States)

    Dubosclard, Pierre; Larnier, Stanislas; Konik, Hubert; Herbulot, Ariane; Devy, Michel

    2015-04-01

    This paper presents two automatic methods for visual grading, designed to solve the industrial problem of evaluation of seed lots from the characterization of a representative sample. The sample is thrown in bulk onto a tray placed in a chamber for acquiring color image in a controlled and reproducible manner. Two image processing methods have been developed to separate, and then characterize each seed present in the image. A shape learning is performed on isolated seeds. Collected information is used for the segmentation. The first approach adopted for the segmentation step is based on simple criteria such as regions, edges and normals to the boundary. Marked point processes are used in the second approach, leading to tackle the problem by a technique of energy minimization. In both approaches, an active contour with shape prior is performed to improve the results. A classification is done on shape or color descriptors to evaluate the quality of the sample.

  15. Automatic visual grading of grain products by machine vision

    Science.gov (United States)

    Dubosclard, Pierre; Larnier, Stanislas; Konik, Hubert; Herbulot, Ariane; Devy, Michel

    2015-11-01

    This paper presents two automatic methods for visual grading, deterministic and probabilistic, designed to solve the industrial problem of evaluation of seed lots from the characterization of a representative sample. The sample is thrown in bulk onto a tray placed in a chamber for acquiring color image in a controlled and reproducible manner. Two image-processing methods have been developed to separate and then characterize each seed present in the image. A shape learning is performed on isolated seeds. Collected information is used for the segmentation. The first approach adopted for the segmentation step is based on simple criteria such as regions, edges, and normals to the boundary. Marked point processes are used in the second approach, leading to tackling of the problem by a technique of energy minimization. In both approaches, an active contour with prior shape is performed to improve the results. A classification is done on shape or color descriptors to evaluate the quality of the sample.

  16. Relativity of Visual Communication

    Directory of Open Access Journals (Sweden)

    Arto Mutanen

    2016-03-01

    Full Text Available Communication is sharing and conveying information. In visual communication especially visual messages have to be formulated and interpreted. The interpretation is relative to a method of information presentation method which is human construction. This holds also in the case of visual languages. The notions of syntax and semantics for visual languages are not so well founded as they are for natural languages. Visual languages are both syntactically and semantically dense. The density is connected to the compositionality of the (pictorial languages. In the paper Charles Sanders Peirce’s theory of signs will be used in characterizing visual languages. This allows us to relate visual languages to natural languages. The foundation of information presentation methods for visual languages is the logic of perception, but only if perception is understood as propositional perception. This allows us to understand better the relativity of information presentation methods, and hence to evaluate the cultural relativity of visual communication.

  17. Shape Perception in 3-D Scatterplots Using Constant Visual Angle Glyphs

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2012-01-01

    When viewing 3-D scatterplots in immersive virtual environments, one commonly encountered problem is the presence of clutter, which obscures the view of any structures of interest in the visualization. In order to solve this problem, we propose to render the 3-D glyphs such that they always cover...... to regular perspective glyphs, especially when a large amount of clutter is present. Furthermore, our evaluation revealed that perception of structures in 3-D scatterplots is significantly affected by the volumetric density of the glyphs in the plot....

  18. 5th Grade Primary School Students’ Perceptions on the Notion of Republic, Reign, and Leadership in the Social

    Directory of Open Access Journals (Sweden)

    Mehmet Suat Bal

    2011-12-01

    Full Text Available The objective of this study is to examine the perceptions of 5th grade students concerning the notion of republic, reign, and leadership, and to identify the reasons of these perceptions. In this research, phenomenography method has been used as the data collection and analysis method. A semi-structured interview form has been used as the data collection method. Randomly selected fifteen 5th grade students, who are attending state schools during the spring semester of 2010-2011 education and instruction year in a Southern province of Turkey, constitute the working group of the current study. The findings reveal that 5th grade students do not perceive the notions by themselves. Students perceive the notion of republic as Ataturk, nation, administration, war, rights, freedom, revolution, symbol, and Turkey. Similarly, the notion of reign is perceived as sultanate, sultan, Ataturk and music, and the notion of leadership is perceived as managership, superiority, manuduction, and victory. In conclusion, many students are not able to associate republic with its true meaning, namely administration, but they are able to associate it with other notions to a large extent. It should be noted that various dimensions of the notions should be emphasized to fully teach them. Also, the basic meaning of the notion should be taken as the focal point

  19. Multisensory Rehabilitation Training Improves Spatial Perception in Totally but Not Partially Visually Deprived Children

    Directory of Open Access Journals (Sweden)

    Giulia Cappagli

    2017-10-01

    Full Text Available Since it has been shown that spatial development can be delayed in blind children, focused sensorimotor trainings that associate auditory and motor information might be used to prevent the risk of spatial-related developmental delays or impairments from an early age. With this aim, we proposed a new technological device based on the implicit link between action and perception: ABBI (Audio Bracelet for Blind Interaction is an audio bracelet that produces a sound when a movement occurs by allowing the substitution of the visuo-motor association with a new audio-motor association. In this study, we assessed the effects of an extensive but entertaining sensorimotor training with ABBI on the development of spatial hearing in a group of seven 3–5 years old children with congenital blindness (n = 2; light perception or no perception of light or low vision (n = 5; visual acuity range 1.1–1.7 LogMAR. The training required the participants to play several spatial games individually and/or together with the psychomotor therapist 1 h per week for 3 months: the spatial games consisted of exercises meant to train their ability to associate visual and motor-related signals from their body, in order to foster the development of multisensory processes. We measured spatial performance by asking participants to indicate the position of one single fixed (static condition or moving (dynamic condition sound source on a vertical sensorized surface. We found that spatial performance of congenitally blind but not low vision children is improved after the training, indicating that early interventions with the use of science-driven devices based on multisensory capabilities can provide consistent advancements in therapeutic interventions, improving the quality of life of children with visual disability.

  20. Which technology to investigate visual perception in sport: video vs. virtual reality.

    Science.gov (United States)

    Vignais, Nicolas; Kulpa, Richard; Brault, Sébastien; Presse, Damien; Bideau, Benoit

    2015-02-01

    Visual information uptake is a fundamental element of sports involving interceptive tasks. Several methodologies, like video and methods based on virtual environments, are currently employed to analyze visual perception during sport situations. Both techniques have advantages and drawbacks. The goal of this study is to determine which of these technologies may be preferentially used to analyze visual information uptake during a sport situation. To this aim, we compared a handball goalkeeper's performance using two standardized methodologies: video clip and virtual environment. We examined this performance for two response tasks: an uncoupled task (goalkeepers show where the ball ends) and a coupled task (goalkeepers try to intercept the virtual ball). Variables investigated in this study were percentage of correct zones, percentage of correct responses, radial error and response time. The results showed that handball goalkeepers were more effective, more accurate and started to intercept earlier when facing a virtual handball thrower than when facing the video clip. These findings suggested that the analysis of visual information uptake for handball goalkeepers was better performed by using a 'virtual reality'-based methodology. Technical and methodological aspects of these findings are discussed further. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. How does glaucoma look?: patient perception of visual field loss.

    Science.gov (United States)

    Crabb, David P; Smith, Nicholas D; Glen, Fiona C; Burton, Robyn; Garway-Heath, David F

    2013-06-01

    To explore patient perception of vision loss in glaucoma and, specifically, to test the hypothesis that patients do not recognize their impairment as a black tunnel effect or as black patches in their field of view. Clinic-based cross-sectional study. Fifty patients (age range, 52-82 years) with visual acuity better than 20/30 and with a range of glaucomatous visual field (VF) defects in both eyes, excluding those with very advanced disease (perimetrically blind). Participants underwent monocular VF testing in both eyes using a Humphrey Field Analyzer (HFA; Carl Zeiss Meditec, Dublin, CA; 24-2 Swedish interactive threshold algorithm standard tests) and other tests of visual function. Participants took part in a recorded interview during which they were asked if they were aware of their VF loss; if so, there were encouraged to describe it in their own words. Participants were shown 6 images modified in a variety of ways on a computer monitor and were asked to select the image that most closely represented their perception of their VF loss. Forced choice of an image best representing glaucomatous vision impairment. Participants had a range of VF defect severity: average HFA mean deviation was -8.7 dB (standard deviation [SD], 5.8 dB) and -10.5 dB (SD, 7.1 dB) in the right and left eyes, respectively. Thirteen patients (26%; 95% confidence interval [CI], 15%-40%) reported being completely unaware of their vision loss. None of the patients chose the images with a distinct black tunnel effect or black patches. Only 2 patients (4%; 95% CI, 0%-14%) chose the image with a tunnel effect with blurred edges. An image depicting blurred patches and another with missing patches was chosen by 54% (95% CI, 39%-68%) and 16% (95% CI, 7%-29%) of the patients, respectively. Content analysis of the transcripts from the recorded interviews indicated a frequent use of descriptors of visual symptoms associated with reported blur and missing features. Patients with glaucoma do not perceive

  2. A color fusion method of infrared and low-light-level images based on visual perception

    Science.gov (United States)

    Han, Jing; Yan, Minmin; Zhang, Yi; Bai, Lianfa

    2014-11-01

    The color fusion images can be obtained through the fusion of infrared and low-light-level images, which will contain both the information of the two. The fusion images can help observers to understand the multichannel images comprehensively. However, simple fusion may lose the target information due to inconspicuous targets in long-distance infrared and low-light-level images; and if targets extraction is adopted blindly, the perception of the scene information will be affected seriously. To solve this problem, a new fusion method based on visual perception is proposed in this paper. The extraction of the visual targets ("what" information) and parallel processing mechanism are applied in traditional color fusion methods. The infrared and low-light-level color fusion images are achieved based on efficient typical targets learning. Experimental results show the effectiveness of the proposed method. The fusion images achieved by our algorithm can not only improve the detection rate of targets, but also get rich natural information of the scenes.

  3. Quantifying the visual perception skills of pre-school testees using a novel tangible electronic test instrument

    CSIR Research Space (South Africa)

    Smith, Andrew C

    2008-11-01

    Full Text Available . These children were found to be less proficient in visualisation skills than their suburban counterparts. A new study was undertaken to ascertain whether there is any difference in cognitive skills, particularly visual perception, between pre-school children from...

  4. Neuron analysis of visual perception

    Science.gov (United States)

    Chow, K. L.

    1980-01-01

    The receptive fields of single cells in the visual system of cat and squirrel monkey were studied investigating the vestibular input affecting the cells, and the cell's responses during visual discrimination learning process. The receptive field characteristics of the rabbit visual system, its normal development, its abnormal development following visual deprivation, and on the structural and functional re-organization of the visual system following neo-natal and prenatal surgery were also studied. The results of each individual part of each investigation are detailed.

  5. Simulating Visual Pattern Detection and Brightness Perception Based on Implicit Masking

    Directory of Open Access Journals (Sweden)

    Yang Jian

    2007-01-01

    Full Text Available A quantitative model of implicit masking, with a front-end low-pass filter, a retinal local compressive nonlinearity described by a modified Naka-Rushton equation, a cortical representation of the image in the Fourier domain, and a frequency-dependent compressive nonlinearity, was developed to simulate visual image processing. The model algorithm was used to estimate contrast sensitivity functions over 7 mean illuminance levels ranging from 0.0009 to 900 trolands, and fit to the contrast thresholds of 43 spatial patterns in the Modelfest study. The RMS errors between model estimations and experimental data in the literature were about 0.1 log unit. In addition, the same model was used to simulate the effects of simultaneous contrast, assimilation, and crispening. The model results matched the visual percepts qualitatively, showing the value of integrating the three diverse perceptual phenomena under a common theoretical framework.

  6. Fornix and medial temporal lobe lesions lead to comparable deficits in complex visual perception.

    Science.gov (United States)

    Lech, Robert K; Koch, Benno; Schwarz, Michael; Suchan, Boris

    2016-05-04

    Recent research dealing with the structures of the medial temporal lobe (MTL) has shifted away from exclusively investigating memory-related processes and has repeatedly incorporated the investigation of complex visual perception. Several studies have demonstrated that higher level visual tasks can recruit structures like the hippocampus and perirhinal cortex in order to successfully perform complex visual discriminations, leading to a perceptual-mnemonic or representational view of the medial temporal lobe. The current study employed a complex visual discrimination paradigm in two patients suffering from brain lesions with differing locations and origin. Both patients, one with extensive medial temporal lobe lesions (VG) and one with a small lesion of the anterior fornix (HJK), were impaired in complex discriminations while showing otherwise mostly intact cognitive functions. The current data confirmed previous results while also extending the perceptual-mnemonic theory of the MTL to the main output structure of the hippocampus, the fornix. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. Disorders of visual perception

    NARCIS (Netherlands)

    Ffytche, Dominic H.; Blom, J. D.; Catani, M.

    Visual perceptual disorders are often presented as a disparate group of neurological deficits with little consideration given to the wide range of visual symptoms found in psychiatric and neurodevelopmental disease. Here, the authors attempt a functional anatomical classification of all disorders

  8. Disorders of visual perception

    NARCIS (Netherlands)

    Ffytche, Dominic H.; Blom, J. D.; Catani, M.

    2010-01-01

    Visual perceptual disorders are often presented as a disparate group of neurological deficits with little consideration given to the wide range of visual symptoms found in psychiatric and neurodevelopmental disease. Here, the authors attempt a functional anatomical classification of all disorders

  9. Intraoperative confocal microscopy in the visualization of 5-aminolevulinic acid fluorescence in low-grade gliomas.

    Science.gov (United States)

    Sanai, Nader; Snyder, Laura A; Honea, Norissa J; Coons, Stephen W; Eschbacher, Jennifer M; Smith, Kris A; Spetzler, Robert F

    2011-10-01

    Greater extent of resection (EOR) for patients with low-grade glioma (LGG) corresponds with improved clinical outcome, yet remains a central challenge to the neurosurgical oncologist. Although 5-aminolevulinic acid (5-ALA)-induced tumor fluorescence is a strategy that can improve EOR in gliomas, only glioblastomas routinely fluoresce following 5-ALA administration. Intraoperative confocal microscopy adapts conventional confocal technology to a handheld probe that provides real-time fluorescent imaging at up to 1000× magnification. The authors report a combined approach in which intraoperative confocal microscopy is used to visualize 5-ALA tumor fluorescence in LGGs during the course of microsurgical resection. Following 5-ALA administration, patients with newly diagnosed LGG underwent microsurgical resection. Intraoperative confocal microscopy was conducted at the following points: 1) initial encounter with the tumor; 2) the midpoint of tumor resection; and 3) the presumed brain-tumor interface. Histopathological analysis of these sites correlated tumor infiltration with intraoperative cellular tumor fluorescence. Ten consecutive patients with WHO Grades I and II gliomas underwent microsurgical resection with 5-ALA and intraoperative confocal microscopy. Macroscopic tumor fluorescence was not evident in any patient. However, in each case, intraoperative confocal microscopy identified tumor fluorescence at a cellular level, a finding that corresponded to tumor infiltration on matched histological analyses. Intraoperative confocal microscopy can visualize cellular 5-ALA-induced tumor fluorescence within LGGs and at the brain-tumor interface. To assess the clinical value of 5-ALA for high-grade gliomas in conjunction with neuronavigation, and for LGGs in combination with intraoperative confocal microscopy and neuronavigation, a Phase IIIa randomized placebo-controlled trial (BALANCE) is underway at the authors' institution.

  10. Perception of visual apparent motion is modulated by a gap within concurrent auditory glides, even when it is illusory

    Science.gov (United States)

    Wang, Qingcui; Guo, Lu; Bao, Ming; Chen, Lihan

    2015-01-01

    Auditory and visual events often happen concurrently, and how they group together can have a strong effect on what is perceived. We investigated whether/how intra- or cross-modal temporal grouping influenced the perceptual decision of otherwise ambiguous visual apparent motion. To achieve this, we juxtaposed auditory gap transfer illusion with visual Ternus display. The Ternus display involves a multi-element stimulus that can induce either of two different percepts of apparent motion: ‘element motion’ (EM) or ‘group motion’ (GM). In “EM,” the endmost disk is seen as moving back and forth while the middle disk at the central position remains stationary; while in “GM,” both disks appear to move laterally as a whole. The gap transfer illusion refers to the illusory subjective transfer of a short gap (around 100 ms) from the long glide to the short continuous glide when the two glides intercede at the temporal middle point. In our experiments, observers were required to make a perceptual discrimination of Ternus motion in the presence of concurrent auditory glides (with or without a gap inside). Results showed that a gap within a short glide imposed a remarkable effect on separating visual events, and led to a dominant perception of GM as well. The auditory configuration with gap transfer illusion triggered the same auditory capture effect. Further investigations showed that visual interval which coincided with the gap interval (50–230 ms) in the long glide was perceived to be shorter than that within both the short glide and the ‘gap-transfer’ auditory configurations in the same physical intervals (gaps). The results indicated that auditory temporal perceptual grouping takes priority over the cross-modal interaction in determining the final readout of the visual perception, and the mechanism of selective attention on auditory events also plays a role. PMID:26042055

  11. Perception of visual apparent motion is modulated by a gap within concurrent auditory glides, even when it is illusory

    Directory of Open Access Journals (Sweden)

    Qingcui eWang

    2015-05-01

    Full Text Available Auditory and visual events often happen concurrently, and how they group together can have a strong effect on what is perceived. We investigated whether/how intra- or cross-modal temporal grouping influenced the perceptual decision of otherwise ambiguous visual apparent motion. To achieve this, we juxtaposed auditory gap transfer illusion with visual Ternus display. The Ternus display involves a multi-element stimulus that can induce either of two different percepts of apparent motion: ‘element motion’ or ‘group motion’. In element motion, the endmost disk is seen as moving back and forth while the middle disk at the central position remains stationary; while in group motion, both disks appear to move laterally as a whole. The gap transfer illusion refers to the illusory subjective transfer of a short gap (around 100 ms from the long glide to the short continuous glide when the two glides intercede at the temporal middle point. In our experiments, observers were required to make a perceptual discrimination of Ternus motion in the presence of concurrent auditory glides (with or without a gap inside. Results showed that a gap within a short glide imposed a remarkable effect on separating visual events, and led to a dominant perception of group motion as well. The auditory configuration with gap transfer illusion triggered the same auditory capture effect. Further investigations showed that visual interval which coincided with the gap interval (50-230 ms in the long glide was perceived to be shorter than that within both the short glide and the ‘gap-transfer’ auditory configurations in the same physical intervals (gaps. The results indicated that auditory temporal perceptual grouping takes priority over the cross-modal interaction in determining the final readout of the visual perception, and the mechanism of selective attention on auditory events also plays a role.

  12. Predicting the Attitudes and Self-Esteem of the Grade 9th Lower Secondary School Students towards Mathematics from Their Perceptions of the Classroom Learning Environment

    Science.gov (United States)

    Tran, Van Dat

    2012-01-01

    This study reports the validity of the hypothesis that students' perceptions of the learning environment of mathematics classroom may predict their attitudes and self-esteem towards mathematics. It examines data from 487 grade 9th students from 14 mathematics classes in 7 Vietnamese lower secondary schools to identify how students' perceptions of…

  13. La Memoria Visual Como Predictor del Aprendizaje de la Lectura Visual Memory as Predictor of Reading Acquisition

    Directory of Open Access Journals (Sweden)

    Mónica Pino

    2005-05-01

    Full Text Available Se presentan los resultados de un estudio longitudinal realizado en alumnos de escuelas municipales de Santiago de Chile, cuyo objetivo fue investigar la relación entre el reconocimiento visual-ortográfico, la percepción y la memoria visual con la lectura inicial. Especialmente se analizó la relación predictiva entre el reconocimiento perceptivo visual de la Figura Compleja de Rey, la memoria visual y el reconocimiento visual-ortográfico con el aprendizaje inicial de la lectura. La muestra estuvo conformada por 105 alumnos de primero básico. Los niños se evaluaron mediante nueve pruebas destinadas al reconocimiento perceptivo visual y visual-ortográfico y una prueba utilizada para evaluar el aprendizaje de la lectura. Los resultados mostraron que la prueba de la Figura Compleja de Rey, que evalúa capacidad de percepción visual, predice significativamente el aprendizaje lector en el nivel inicial.The aim of this article is to present the results of a longitudinal study of a group of public school pupils on their visualperception, visual memory and visual-orthographic recognizing of words and their predictivity on early reading. The sample was comprised of 105 first grade students. The children were assessed using nine tests to measure visual and visual-ortographic perceptual recognition, and a test to measure their reading ability. Results show that Rey's test, which assesses visual perception ability, has a predictive value on initial reading in Spanish speaking Chilean children.

  14. Relationships between Categorical Perception of Phonemes, Phoneme Awareness, and Visual Attention Span in Developmental Dyslexia.

    Directory of Open Access Journals (Sweden)

    Rachel Zoubrinetzky

    Full Text Available We tested the hypothesis that the categorical perception deficit of speech sounds in developmental dyslexia is related to phoneme awareness skills, whereas a visual attention (VA span deficit constitutes an independent deficit. Phoneme awareness tasks, VA span tasks and categorical perception tasks of phoneme identification and discrimination using a d/t voicing continuum were administered to 63 dyslexic children and 63 control children matched on chronological age. Results showed significant differences in categorical perception between the dyslexic and control children. Significant correlations were found between categorical perception skills, phoneme awareness and reading. Although VA span correlated with reading, no significant correlations were found between either categorical perception or phoneme awareness and VA span. Mediation analyses performed on the whole dyslexic sample suggested that the effect of categorical perception on reading might be mediated by phoneme awareness. This relationship was independent of the participants' VA span abilities. Two groups of dyslexic children with a single phoneme awareness or a single VA span deficit were then identified. The phonologically impaired group showed lower categorical perception skills than the control group but categorical perception was similar in the VA span impaired dyslexic and control children. The overall findings suggest that the link between categorical perception, phoneme awareness and reading is independent from VA span skills. These findings provide new insights on the heterogeneity of developmental dyslexia. They suggest that phonological processes and VA span independently affect reading acquisition.

  15. Relationships between Categorical Perception of Phonemes, Phoneme Awareness, and Visual Attention Span in Developmental Dyslexia.

    Science.gov (United States)

    Zoubrinetzky, Rachel; Collet, Gregory; Serniclaes, Willy; Nguyen-Morel, Marie-Ange; Valdois, Sylviane

    2016-01-01

    We tested the hypothesis that the categorical perception deficit of speech sounds in developmental dyslexia is related to phoneme awareness skills, whereas a visual attention (VA) span deficit constitutes an independent deficit. Phoneme awareness tasks, VA span tasks and categorical perception tasks of phoneme identification and discrimination using a d/t voicing continuum were administered to 63 dyslexic children and 63 control children matched on chronological age. Results showed significant differences in categorical perception between the dyslexic and control children. Significant correlations were found between categorical perception skills, phoneme awareness and reading. Although VA span correlated with reading, no significant correlations were found between either categorical perception or phoneme awareness and VA span. Mediation analyses performed on the whole dyslexic sample suggested that the effect of categorical perception on reading might be mediated by phoneme awareness. This relationship was independent of the participants' VA span abilities. Two groups of dyslexic children with a single phoneme awareness or a single VA span deficit were then identified. The phonologically impaired group showed lower categorical perception skills than the control group but categorical perception was similar in the VA span impaired dyslexic and control children. The overall findings suggest that the link between categorical perception, phoneme awareness and reading is independent from VA span skills. These findings provide new insights on the heterogeneity of developmental dyslexia. They suggest that phonological processes and VA span independently affect reading acquisition.

  16. Relationships between Categorical Perception of Phonemes, Phoneme Awareness, and Visual Attention Span in Developmental Dyslexia

    Science.gov (United States)

    Zoubrinetzky, Rachel; Collet, Gregory; Serniclaes, Willy; Nguyen-Morel, Marie-Ange; Valdois, Sylviane

    2016-01-01

    We tested the hypothesis that the categorical perception deficit of speech sounds in developmental dyslexia is related to phoneme awareness skills, whereas a visual attention (VA) span deficit constitutes an independent deficit. Phoneme awareness tasks, VA span tasks and categorical perception tasks of phoneme identification and discrimination using a d/t voicing continuum were administered to 63 dyslexic children and 63 control children matched on chronological age. Results showed significant differences in categorical perception between the dyslexic and control children. Significant correlations were found between categorical perception skills, phoneme awareness and reading. Although VA span correlated with reading, no significant correlations were found between either categorical perception or phoneme awareness and VA span. Mediation analyses performed on the whole dyslexic sample suggested that the effect of categorical perception on reading might be mediated by phoneme awareness. This relationship was independent of the participants’ VA span abilities. Two groups of dyslexic children with a single phoneme awareness or a single VA span deficit were then identified. The phonologically impaired group showed lower categorical perception skills than the control group but categorical perception was similar in the VA span impaired dyslexic and control children. The overall findings suggest that the link between categorical perception, phoneme awareness and reading is independent from VA span skills. These findings provide new insights on the heterogeneity of developmental dyslexia. They suggest that phonological processes and VA span independently affect reading acquisition. PMID:26950210

  17. Navigating middle grades: role of social contexts in middle grade school climate.

    Science.gov (United States)

    Kim, Ha Yeon; Schwartz, Kate; Cappella, Elise; Seidman, Edward

    2014-09-01

    During early adolescence, most public school students undergo school transitions, and many students experience declines in academic performance and social-emotional well-being. Theories and empirical research have highlighted the importance of supportive school environments in promoting positive youth development during this period of transition. Despite this, little is known about the proximal social and developmental contexts of the range of middle grade public schools US students attend. Using a cross-sectional dataset from the eighth grade wave of the Early Childhood Longitudinal Study-Kindergarten Cohort 1998-1999, the current study examines the middle grade school social context from the perspectives of administrators and teachers in public schools with typical grade configurations (k-8 schools, middle schools, and junior high schools) and how it relates to students' perceptions of school climate. We find that administrators and teachers in k-8 schools perceive a more positive school social context, controlling for school structural and demographic characteristics. This school social context, in turn, is associated with students' perceptions of their schools' social and academic climate. Implications for educational policy and practice are discussed.

  18. Validity of the growth model of the 'computerized visual perception assessment tool for Chinese characters structures'.

    Science.gov (United States)

    Wu, Huey-Min; Li, Cheng-Hsaun; Kuo, Bor-Chen; Yang, Yu-Mao; Lin, Chin-Kai; Wan, Wei-Hsiang

    2017-08-01

    Morphological awareness is the foundation for the important developmental skills involved with vocabulary, as well as understanding the meaning of words, orthographic knowledge, reading, and writing. Visual perception of space and radicals in two-dimensional positions of Chinese characters' morphology is very important in identifying Chinese characters. The important predictive variables of special and visual perception in Chinese characters identification were investigated in the growth model in this research. The assessment tool is the "Computerized Visual Perception Assessment Tool for Chinese Characters Structures" developed by this study. There are two constructs, basic stroke and character structure. In the basic stroke, there are three subtests of one, two, and more than three strokes. In the character structure, there are three subtests of single-component character, horizontal-compound character, and vertical-compound character. This study used purposive sampling. In the first year, 551 children 4-6 years old participated in the study and were monitored for one year. In the second year, 388 children remained in the study and the successful follow-up rate was 70.4%. This study used a two-wave cross-lagged panel design to validate the growth model of the basic stroke and the character structure. There was significant correlation of the basic stroke and the character structure at different time points. The abilities in the basic stroke and in the character structure steadily developed over time for preschool children. Children's knowledge of the basic stroke effectively predicted their knowledge of the basic stroke and the character structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Design Improvements on Graded Insulation of Power Transformers Using Transient Electric Field Analysis and Visualization Technique

    OpenAIRE

    Yamashita, Hideo; Nakamae, Eihachiro; Namera, Akihiro; Cingoski, Vlatko; Kitamura, Hideo

    1998-01-01

    This paper deals with design improvements on graded insulation of power transformers using transient electric field analysis and a visualization technique. The calculation method for transient electric field analysis inside a power transformer impressed with impulse voltage is presented: Initially, the concentrated electric network for the power transformer is concentrated by dividing transformer windings into several blocks and by computing the electric circuit parameters.

  20. Visual perception and consciousness in dermatopathology: mechanisms of figure-ground segregation account for errors in diagnosis.

    Science.gov (United States)

    Böer, Almut

    2009-02-01

    Visual perception has been the object of research in psychology for almost a century. Little has been written, however, about the effects of perceptive phenomena on methods in medicine that utilize interpretation of two-dimensional images for diagnosis. Starting from the work by Edgar Rubin in the beginning of the last century, this article gives a summary of observations of psychologists who investigated the mechanisms of so-called "figure-ground segregation." These unconscious mechanisms follow rules that explain why certain structures are perceived consciously as a figure, whereas other structures surrounding such a figure are neglected and not perceived consciously in detail. Perception of a structure as a figure can be due to, for example, a convex shape of its contour, proximity of lines around it, closed contours, a simple shape, and attribution of meaning to a structure. In examples from the practice of dermatopathology, those unconscious mechanisms of figure-ground segregation will be shown to be relevant to diagnosis of sections of tissue. The mechanisms help to explain why, for example, ill-defined and concave-shaped structures, stromal differences of neoplasms, interstitial infiltrates and deposits, and simulators of common diseases are often difficult to recognize at first sight. Teachers of dermatopathology need to be aware of these unconscious mechanisms of visual perception because they explain why novices struggle with certain diagnoses and differential diagnoses. Proper instruction about these phenomena, early in the process of training, will prevent a student from being frustrated with misperceptions.

  1. Embodied perception: A proposal to reconcile affordance and spatial perception

    NARCIS (Netherlands)

    Canal Bruland, R.; van der Kamp, J.

    2015-01-01

    Proffitt's embodied approach to perception is deeply indebted to Gibson's ecological approach to visual perception, in particular the idea that the primary objects of perception are affordances or what the environment offers for action. Yet, rather than directly addressing affordance perception,

  2. Parents' Perceptions of Professional Support for the Emergent Literacy of Young Children with Visual Impairments

    Science.gov (United States)

    Brennan, Susan A.; Luze, Gayle J.; Peterson, Carla

    2009-01-01

    This survey explored the emergent literacy experiences that parents provided for their children with visual impairments, aged 1-8, as well as the parents' perceptions of the professional support that they received to facilitate these activities. The results indicated that the parents and children engaged in reading, singing songs, and writing or…

  3. Auditory Motion Elicits a Visual Motion Aftereffect.

    Science.gov (United States)

    Berger, Christopher C; Ehrsson, H Henrik

    2016-01-01

    The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect-an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  4. Auditory Motion Elicits a Visual Motion Aftereffect

    Directory of Open Access Journals (Sweden)

    Christopher C. Berger

    2016-12-01

    Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  5. The effect of two different visual presentation modalities on the narratives of mainstream grade 3 children

    Directory of Open Access Journals (Sweden)

    Daleen Klop

    2013-11-01

    Method: Twenty mainstream grade 3 children were randomly assigned to two groups and assessed with one of the visual presentation methods. Narrative performance was measured in terms of micro- and macrostructure variables. Microstructure variables included productivity (total number of words, total number of T-units, syntactic complexity (mean length of T-unit and lexical diversity measures (number of different words. Macrostructure variables included episodic structure in terms of goal-attempt-outcome (GAO sequences. Results: Both visual presentation modalities elicited narratives of similar quantity and quality in terms of the micro- and macrostructure variables that were investigated. Conclusion: Animation of picture stimuli did not elicit better narratives than static picture stimuli.

  6. Comparison of Congruence Judgment and Auditory Localization Tasks for Assessing the Spatial Limits of Visual Capture

    Science.gov (United States)

    Bosen, Adam K.; Fleming, Justin T.; Brown, Sarah E.; Allen, Paul D.; O'Neill, William E.; Paige, Gary D.

    2016-01-01

    Vision typically has better spatial accuracy and precision than audition, and as a result often captures auditory spatial perception when visual and auditory cues are presented together. One determinant of visual capture is the amount of spatial disparity between auditory and visual cues: when disparity is small visual capture is likely to occur, and when disparity is large visual capture is unlikely. Previous experiments have used two methods to probe how visual capture varies with spatial disparity. First, congruence judgment assesses perceived unity between cues by having subjects report whether or not auditory and visual targets came from the same location. Second, auditory localization assesses the graded influence of vision on auditory spatial perception by having subjects point to the remembered location of an auditory target presented with a visual target. Previous research has shown that when both tasks are performed concurrently they produce similar measures of visual capture, but this may not hold when tasks are performed independently. Here, subjects alternated between tasks independently across three sessions. A Bayesian inference model of visual capture was used to estimate perceptual parameters for each session, which were compared across tasks. Results demonstrated that the range of audio-visual disparities over which visual capture was likely to occur were narrower in auditory localization than in congruence judgment, which the model indicates was caused by subjects adjusting their prior expectation that targets originated from the same location in a task-dependent manner. PMID:27815630

  7. Phonological Contribution during Visual Word Recognition in Child Readers. An Intermodal Priming Study in Grades 3 and 5

    Science.gov (United States)

    Sauval, Karinne; Casalis, Séverine; Perre, Laetitia

    2017-01-01

    This study investigated the phonological contribution during visual word recognition in child readers as a function of general reading expertise (third and fifth grades) and specific word exposure (frequent and less-frequent words). An intermodal priming in lexical decision task was performed. Auditory primes (identical and unrelated) were used in…

  8. Brain mechanisms for simple perception and bistable perception.

    Science.gov (United States)

    Wang, Megan; Arteaga, Daniel; He, Biyu J

    2013-08-27

    When faced with ambiguous sensory inputs, subjective perception alternates between the different interpretations in a stochastic manner. Such multistable perception phenomena have intrigued scientists and laymen alike for over a century. Despite rigorous investigations, the underlying mechanisms of multistable perception remain elusive. Recent studies using multivariate pattern analysis revealed that activity patterns in posterior visual areas correlate with fluctuating percepts. However, increasing evidence suggests that vision--and perception at large--is an active inferential process involving hierarchical brain systems. We applied searchlight multivariate pattern analysis to functional magnetic resonance imaging signals across the human brain to decode perceptual content during bistable perception and simple unambiguous perception. Although perceptually reflective activity patterns during simple perception localized predominantly to posterior visual regions, bistable perception involved additionally many higher-order frontoparietal and temporal regions. Moreover, compared with simple perception, both top-down and bottom-up influences were dramatically enhanced during bistable perception. We further studied the intermittent presentation of ambiguous images--a condition that is known to elicit perceptual memory. Compared with continuous presentation, intermittent presentation recruited even more higher-order regions and was accompanied by further strengthened top-down influences but relatively weakened bottom-up influences. Taken together, these results strongly support an active top-down inferential process in perception.

  9. Dysfunctions of visual and auditory Gestalt perception (amusia) after stroke : Behavioral correlates and functional magnetic resonance imaging

    OpenAIRE

    Rosemann, Stephanie Heike

    2016-01-01

    Music is a special and unique part of human nature. Not only actively playing (making music in a group or alone) but also passive listening to music involves a richness of processes to make music the ideal tool to investigate how the human brain works. Acquired amusia denotes the impaired perception of melodies, rhythms, and the associated disability to enjoy music which can occur after a stroke. Many amusia patients also show deficits in visual perception, language, memory, and attention. He...

  10. Influences of selective adaptation on perception of audiovisual speech

    Science.gov (United States)

    Dias, James W.; Cook, Theresa C.; Rosenblum, Lawrence D.

    2016-01-01

    Research suggests that selective adaptation in speech is a low-level process dependent on sensory-specific information shared between the adaptor and test-stimuli. However, previous research has only examined how adaptors shift perception of unimodal test stimuli, either auditory or visual. In the current series of experiments, we investigated whether adaptation to cross-sensory phonetic information can influence perception of integrated audio-visual phonetic information. We examined how selective adaptation to audio and visual adaptors shift perception of speech along an audiovisual test continuum. This test-continuum consisted of nine audio-/ba/-visual-/va/ stimuli, ranging in visual clarity of the mouth. When the mouth was clearly visible, perceivers “heard” the audio-visual stimulus as an integrated “va” percept 93.7% of the time (e.g., McGurk & MacDonald, 1976). As visibility of the mouth became less clear across the nine-item continuum, the audio-visual “va” percept weakened, resulting in a continuum ranging in audio-visual percepts from /va/ to /ba/. Perception of the test-stimuli was tested before and after adaptation. Changes in audiovisual speech perception were observed following adaptation to visual-/va/ and audiovisual-/va/, but not following adaptation to auditory-/va/, auditory-/ba/, or visual-/ba/. Adaptation modulates perception of integrated audio-visual speech by modulating the processing of sensory-specific information. The results suggest that auditory and visual speech information are not completely integrated at the level of selective adaptation. PMID:27041781

  11. Comparison of congruence judgment and auditory localization tasks for assessing the spatial limits of visual capture.

    Science.gov (United States)

    Bosen, Adam K; Fleming, Justin T; Brown, Sarah E; Allen, Paul D; O'Neill, William E; Paige, Gary D

    2016-12-01

    Vision typically has better spatial accuracy and precision than audition and as a result often captures auditory spatial perception when visual and auditory cues are presented together. One determinant of visual capture is the amount of spatial disparity between auditory and visual cues: when disparity is small, visual capture is likely to occur, and when disparity is large, visual capture is unlikely. Previous experiments have used two methods to probe how visual capture varies with spatial disparity. First, congruence judgment assesses perceived unity between cues by having subjects report whether or not auditory and visual targets came from the same location. Second, auditory localization assesses the graded influence of vision on auditory spatial perception by having subjects point to the remembered location of an auditory target presented with a visual target. Previous research has shown that when both tasks are performed concurrently they produce similar measures of visual capture, but this may not hold when tasks are performed independently. Here, subjects alternated between tasks independently across three sessions. A Bayesian inference model of visual capture was used to estimate perceptual parameters for each session, which were compared across tasks. Results demonstrated that the range of audiovisual disparities over which visual capture was likely to occur was narrower in auditory localization than in congruence judgment, which the model indicates was caused by subjects adjusting their prior expectation that targets originated from the same location in a task-dependent manner.

  12. Emotionalization in Science Communication: The Impact of Narratives and Visual Representations on Knowledge Gain and Risk Perception

    Directory of Open Access Journals (Sweden)

    Danny Flemming

    2018-01-01

    Full Text Available The communication of scientific information plays an increasingly important role for scientists and scientific institutions. This is especially true of institutions in the field of biodiversity and conservation research, since the transfer of research results to the public is a prerequisite for decision-making, and the success of conservation measures often depends on public acceptance or active contribution. To have the desired impact, science communication in the context of human–wildlife interactions must enable recipients to (1 gain valid knowledge, (2 form an attitude toward the subject matter, and (3 develop an adequate understanding of the risks and dangers associated with human–wildlife interactions, which are usually overestimated by the general public. Using the topic of foxes in urban habitats, we investigated the role of emotionalization in science communication. In a laboratory experiment with 127 university students (91 females, we manipulated textual and visual features in an information brochure about foxes and examined their impact on people’s knowledge gain, attitude development, and modified risk perception. In particular, we compared a narrative presentation to a non-narrative list of facts and examined the use of photographs of young foxes. We found a positive development in all of the outcome variables from the pre- to the posttest (more knowledge, more positive attitude, lower risk perception. We also found an interaction effect of text type and visualization on knowledge gain that highlighted the importance of the fit between text type and visualization. In contrast to our expectations, we did not find any differential effects of specific treatments on attitude development. Finally, we found a main effect of text type on modified risk perception, indicating less reduction of risk perception with a narrative article than with a fact list. We discuss our findings with respect to the role of emotionalization in science

  13. The development and discussion of computerized visual perception assessment tool for Chinese characters structures - Concurrent estimation of the overall ability and the domain ability in item response theory approach.

    Science.gov (United States)

    Wu, Huey-Min; Lin, Chin-Kai; Yang, Yu-Mao; Kuo, Bor-Chen

    2014-11-12

    Visual perception is the fundamental skill required for a child to recognize words, and to read and write. There was no visual perception assessment tool developed for preschool children based on Chinese characters in Taiwan. The purposes were to develop the computerized visual perception assessment tool for Chinese Characters Structures and to explore the psychometrical characteristic of assessment tool. This study adopted purposive sampling. The study evaluated 551 kindergarten-age children (293 boys, 258 girls) ranging from 46 to 81 months of age. The test instrument used in this study consisted of three subtests and 58 items, including tests of basic strokes, single-component characters, and compound characters. Based on the results of model fit analysis, the higher-order item response theory was used to estimate the performance in visual perception, basic strokes, single-component characters, and compound characters simultaneously. Analyses of variance were used to detect significant difference in age groups and gender groups. The difficulty of identifying items in a visual perception test ranged from -2 to 1. The visual perception ability of 4- to 6-year-old children ranged from -1.66 to 2.19. Gender did not have significant effects on performance. However, there were significant differences among the different age groups. The performance of 6-year-olds was better than that of 5-year-olds, which was better than that of 4-year-olds. This study obtained detailed diagnostic scores by using a higher-order item response theory model to understand the visual perception of basic strokes, single-component characters, and compound characters. Further statistical analysis showed that, for basic strokes and compound characters, girls performed better than did boys; there also were differences within each age group. For single-component characters, there was no difference in performance between boys and girls. However, again the performance of 6-year-olds was better than

  14. Grade repetition and parents' perception of hearing loss: An analysis of data from children in the United States.

    Science.gov (United States)

    Gilani, Sapideh; Roditi, Rachel; Bhattacharyya, Neil

    2017-03-01

    To determine whether parent-perceived hearing problems are associated with grade repetition among children in the United States. Retrospective cohort analysis of a contemporary national database. The National Survey of Children's Health 2011 to 2012 was analyzed. Hearing loss, as perceived and reported by parents, was categorized as: no hearing problem, history of a hearing problem, or current hearing problem. Children never repeating a grade versus repeating one or more grades (kindergarten-high school) were identified. Univariate statistics and multivariate logistic regression analyzed the association of hearing problems with grade repetition. Patients with mental retardation, autism, and attention-deficit/hyperactivity disorder were excluded from the analysis. After adjusting for race, sex, and poverty level, odds ratios for grade repetition were computed. Among 66.1 million (average age, 8.3 years, 49.0% male) children, 97.3% never had a hearing problem, 1.7% had a history of a hearing problem, and 1.0% had a current hearing problem. Overall, 7.1% repeated a grade. Grade repetition was reported in 6.9% of children without a hearing problem versus 9.4% with a history of a hearing problem and 19.3% with a current hearing problem (P hearing problem demonstrated an odds ratio of 1.9 (95% confidence interval 0.82-4.13) for grade repetition, whereas a current hearing problem demonstrated an odds ratio of 3.0 (1.90-4.80). Parents' perception of children's hearing problems is strongly associated with grade repetition. This trend is noticed in elementary school more than in high school. 4. Laryngoscope, 127:741-745, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  15. First-person and third-person verbs in visual motion-perception regions.

    Science.gov (United States)

    Papeo, Liuba; Lingnau, Angelika

    2015-02-01

    Verb-related activity is consistently found in the left posterior lateral cortex (PLTC), encompassing also regions that respond to visual-motion perception. Besides motion, those regions appear sensitive to distinctions among the entities beyond motion, including that between first- vs. third-person ("third-person bias"). In two experiments, using functional magnetic resonance imaging (fMRI), we studied whether the implied subject (first/third-person) and/or the semantic content (motor/non-motor) of verbs modulate the neural activity in the left PLTC-regions responsive during basic- and biological-motion perception. In those sites, we found higher activity for verbs than for nouns. This activity was modulated by the person (but not the semantic content) of the verbs, with stronger response to third- than first-person verbs. The third-person bias elicited by verbs supports a role of motion-processing regions in encoding information about the entity beyond (and independently from) motion, and sets in a new light the role of these regions in verb processing. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Visual and auditory socio-cognitive perception in unilateral temporal lobe epilepsy in children and adolescents: a prospective controlled study.

    Science.gov (United States)

    Laurent, Agathe; Arzimanoglou, Alexis; Panagiotakaki, Eleni; Sfaello, Ignacio; Kahane, Philippe; Ryvlin, Philippe; Hirsch, Edouard; de Schonen, Scania

    2014-12-01

    A high rate of abnormal social behavioural traits or perceptual deficits is observed in children with unilateral temporal lobe epilepsy. In the present study, perception of auditory and visual social signals, carried by faces and voices, was evaluated in children or adolescents with temporal lobe epilepsy. We prospectively investigated a sample of 62 children with focal non-idiopathic epilepsy early in the course of the disorder. The present analysis included 39 children with a confirmed diagnosis of temporal lobe epilepsy. Control participants (72), distributed across 10 age groups, served as a control group. Our socio-perceptual evaluation protocol comprised three socio-visual tasks (face identity, facial emotion and gaze direction recognition), two socio-auditory tasks (voice identity and emotional prosody recognition), and three control tasks (lip reading, geometrical pattern and linguistic intonation recognition). All 39 patients also benefited from a neuropsychological examination. As a group, children with temporal lobe epilepsy performed at a significantly lower level compared to the control group with regards to recognition of facial identity, direction of eye gaze, and emotional facial expressions. We found no relationship between the type of visual deficit and age at first seizure, duration of epilepsy, or the epilepsy-affected cerebral hemisphere. Deficits in socio-perceptual tasks could be found independently of the presence of deficits in visual or auditory episodic memory, visual non-facial pattern processing (control tasks), or speech perception. A normal FSIQ did not exempt some of the patients from an underlying deficit in some of the socio-perceptual tasks. Temporal lobe epilepsy not only impairs development of emotion recognition, but can also impair development of perception of other socio-perceptual signals in children with or without intellectual deficiency. Prospective studies need to be designed to evaluate the results of appropriate re

  17. Visual exposure to large and small portion sizes and perceptions of portion size normality: Three experimental studies

    OpenAIRE

    Robinson, Eric; Oldham, Melissa; Cuckson, Imogen; Brunstrom, Jeffrey M.; Rogers, Peter J.; Hardman, Charlotte A.

    2016-01-01

    Portion sizes of many foods have increased in recent times. In three studies we examined the effect that repeated visual exposure to larger versus smaller food portion sizes has on perceptions of what constitutes a normal-sized food portion and measures of portion size selection. In studies 1 and 2 participants were visually exposed to images of large or small portions of spaghetti bolognese, before making evaluations about an image of an intermediate sized portion of the same food. In study ...

  18. Fusion of perceptions for perceptual robotics

    NARCIS (Netherlands)

    Ciftcioglu, O.; Bittermann, M.S.; Sariyildiz, I.S.

    2006-01-01

    Fusion of perception information for perceptual robotics is described. The visual perception is mathematically modelled as a probabilistic process obtaining and interpreting visual data from an environment. The visual data is processed in a multiresolutional form via wavelet transform and optimally

  19. Behavioral model of visual perception and recognition

    Science.gov (United States)

    Rybak, Ilya A.; Golovan, Alexander V.; Gusakova, Valentina I.

    1993-09-01

    In the processes of visual perception and recognition human eyes actively select essential information by way of successive fixations at the most informative points of the image. A behavioral program defining a scanpath of the image is formed at the stage of learning (object memorizing) and consists of sequential motor actions, which are shifts of attention from one to another point of fixation, and sensory signals expected to arrive in response to each shift of attention. In the modern view of the problem, invariant object recognition is provided by the following: (1) separated processing of `what' (object features) and `where' (spatial features) information at high levels of the visual system; (2) mechanisms of visual attention using `where' information; (3) representation of `what' information in an object-based frame of reference (OFR). However, most recent models of vision based on OFR have demonstrated the ability of invariant recognition of only simple objects like letters or binary objects without background, i.e. objects to which a frame of reference is easily attached. In contrast, we use not OFR, but a feature-based frame of reference (FFR), connected with the basic feature (edge) at the fixation point. This has provided for our model, the ability for invariant representation of complex objects in gray-level images, but demands realization of behavioral aspects of vision described above. The developed model contains a neural network subsystem of low-level vision which extracts a set of primary features (edges) in each fixation, and high- level subsystem consisting of `what' (Sensory Memory) and `where' (Motor Memory) modules. The resolution of primary features extraction decreases with distances from the point of fixation. FFR provides both the invariant representation of object features in Sensor Memory and shifts of attention in Motor Memory. Object recognition consists in successive recall (from Motor Memory) and execution of shifts of attention and

  20. Visual features for perception, attention, and working memory: Toward a three-factor framework.

    Science.gov (United States)

    Huang, Liqiang

    2015-12-01

    Visual features are the general building blocks for attention, perception, and working memory. Here, I explore the factors which can quantitatively predict all the differences they make in various paradigms. I tried to combine the strengths of experimental and correlational approaches in a novel way by developing an individual-item differences analysis to extract the factors from 16 stimulus types on the basis of their roles in eight tasks. A large sample size (410) ensured that all eight tasks had a reliability (Cronbach's α) of no less than 0.975, allowing the factors to be precisely determined. Three orthogonal factors were identified which correspond respectively to featural strength (i.e., how close a stimulus is to a basic feature), visual strength (i.e., visual quality of the stimulus), and spatial strength (i.e., how well a stimulus can be represented as a spatial structure). Featural strength helped substantially in all the tasks but moderately less so in perceptual discrimination; visual strength helped substantially in low-level tasks but not in high-level tasks; and spatial strength helped change detection but hindered ensemble matching and visual search. Jointly, these three factors explained 96.4% of all the variances of the eight tasks, making it clear that they account for almost everything about the roles of these 16 stimulus types in these eight tasks. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. The Relation of Visual and Auditory Aptitudes to First Grade Low Readers' Achievement under Sight-Word and Systematic Phonic Instructions. Research Report #36.

    Science.gov (United States)

    Gallistel, Elizabeth; And Others

    Ten auditory and ten visual aptitude measures were administered in the middle of first grade to a sample of 58 low readers. More than half of this low reader sample had scored more than a year below expected grade level on two or more aptitudes. Word recognition measures were administered after four months of sight word instruction and again after…

  2. The Effects of Visual Beats on Prosodic Prominence: Acoustic Analyses, Auditory Perception and Visual Perception

    Science.gov (United States)

    Krahmer, Emiel; Swerts, Marc

    2007-01-01

    Speakers employ acoustic cues (pitch accents) to indicate that a word is important, but may also use visual cues (beat gestures, head nods, eyebrow movements) for this purpose. Even though these acoustic and visual cues are related, the exact nature of this relationship is far from well understood. We investigate whether producing a visual beat…

  3. Intention to respond to local wind turbines: the role of attitudes and visual perception

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Maria; Laike, Thorbjorn [Environmental Psychology Unit, Department of Architecture and the Built Environment, Lund University, PO Box 118, SE-221 00 Lund, (Sweden)

    2007-06-21

    Wind power projects frequently face public opposition during the siting process. A deeper understanding of social factors has therefore been called for. Based on psychological theories, the present research was initiated in order to study the relative importance of individual aspects related to visual perception and attitudinal factors in public intention to oppose local wind turbines. In an empirical study, 80 people assessed the visual characteristics of wind turbines on site and rated their emotional state. They also completed a questionnaire covering attitudes towards the turbines, perception of significant others' opinions of local wind turbines, and perceived possibilities to oppose as well as intention to oppose local turbines. Moreover, socio-demographics, factors related to the place of residence and general attitude towards wind power, were investigated. In a multiple regression analysis explaining 50% of the variance, it was found that intention to oppose was related to only a few perceptual and attitudinal factors, i.e. the perceived unity of the environment, the personal attitude towards the effects of wind turbines on landscape aesthetics and recreation, and the general attitude towards wind power. Of minor importance was the attitude towards the effects of wind turbines on people's daily quality of life. It seems important to involve the public in the discussion of how wind power installations can be integrated into the landscape without threatening the visual beauty and the recreational value of the natural and cultural environment. Moreover, social intervention is required to promote positive attitudes towards wind turbines. (Author).

  4. Vision as subjective perception; La vision, une perception subjective

    Energy Technology Data Exchange (ETDEWEB)

    Reppas, J.B. [Harvard Univ., Cambridge, MA (United States). Biological Labs.; Dale, A.; Sereno, M.; Tootell, R.

    1996-07-01

    The human brain is not very different of the monkey`s one: at least, its visual cortex is organized as a similar scheme. Specialized areas in the movement analysis are found and others in the forms perception. In this work, the author tries to answer to the following questions: (1)why so many visual areas? What are exactly their role in vision? Thirteen years of experimentation have not allowed to answer to these questions. The cerebral NMR imaging gives the opportunity of understanding the subjective perception of the visual world. One step which is particularly described in this work is to know how the visual cortex reacts to the optical illusions. (O.M.).

  5. Basic to Applied Research: The Benefits of Audio-Visual Speech Perception Research in Teaching Foreign Languages

    Science.gov (United States)

    Erdener, Dogu

    2016-01-01

    Traditionally, second language (L2) instruction has emphasised auditory-based instruction methods. However, this approach is restrictive in the sense that speech perception by humans is not just an auditory phenomenon but a multimodal one, and specifically, a visual one as well. In the past decade, experimental studies have shown that the…

  6. Confinement has no effect on visual space perception: The results of the Mars-500 experiment

    Czech Academy of Sciences Publication Activity Database

    Šikl, Radovan; Šimeček, Michal

    2014-01-01

    Roč. 76, č. 2 (2014), s. 438-451 ISSN 1943-3921 R&D Projects: GA ČR(CZ) GAP407/12/2528 Institutional support: RVO:68081740 Keywords : visual space perception * perspective * Mars-500 * size judgment * size constancy * confinement Subject RIV: AN - Psychology Impact factor: 2.168, year: 2014 http://dx.doi.org/10.3758/s13414-013-0594-y

  7. P2-7: Encoding of Graded Changes in Validity of Spatial Priors in Human Visual Cortex

    Directory of Open Access Journals (Sweden)

    Yuko Hara

    2012-10-01

    Full Text Available If the spatial validity of prior information is varied systematically, does human behavioral performance improve in a graded fashion, and if so, does visual cortex represent the probability directly? Cortical activity was measured with fMRI while subjects performed a contrast-discrimination task in which the spatial validity of a prior cue for target location was systematically varied. Subjects viewed four sinusoidal gratings (randomized contrasts of 12.5, 25, and 50% shown in discrete visual quadrants presented twice. The contrast in one location (target was incremented in one of the two presentations. Subjects reported with a button press which presentation contained the greater contrast. The target grating was signaled in advance by a cue which varied in spatial validity; at trial onset, small lines pointed to four, two, or one of the possible target locations, thus indicating the target with 25, 50, or 100% probability. Behavioral performance was 2.1 and 3.3 times better in the 100% probability condition than the 50% and 25%, respectively (p < .001, ANOVA. Unlike behavioral performance, cortical activity in early visual areas showed the same increase in response amplitude for cued versus uncued stimuli for both 100% and 50% probability (V1-V4, V3A all p < .18, Student's t-test, 25% had no uncued condition. How could behavioral performance improve in a graded fashion if cortical activity showed the same effect for different probabilities? A model of efficient selection in which V1 responses were pooled according to their magnitude rather than as a simple average explained the observations (AIC difference = −15.

  8. Teaching with Concrete and Abstract Visual Representations: Effects on Students' Problem Solving, Problem Representations, and Learning Perceptions

    Science.gov (United States)

    Moreno, Roxana; Ozogul, Gamze; Reisslein, Martin

    2011-01-01

    In 3 experiments, we examined the effects of using concrete and/or abstract visual problem representations during instruction on students' problem-solving practice, near transfer, problem representations, and learning perceptions. In Experiments 1 and 2, novice students learned about electrical circuit analysis with an instructional program that…

  9. Master's Thesis Supervision: Relations between Perceptions of the Supervisor-Student Relationship, Final Grade, Perceived Supervisor Contribution to Learning and Student Satisfaction

    Science.gov (United States)

    de Kleijn, Renske A. M.; Mainhard, M. Tim; Meijer, Paulien C.; Pilot, Albert; Brekelmans, Mieke

    2012-01-01

    Master's thesis supervision is a complex task given the two-fold goal of the thesis (learning and assessment). An important aspect of supervision is the supervisor-student relationship. This quantitative study (N = 401) investigates how perceptions of the supervisor-student relationship are related to three dependent variables: final grade,…

  10. Suppressive mechanisms in visual motion processing: From perception to intelligence.

    Science.gov (United States)

    Tadin, Duje

    2015-10-01

    Perception operates on an immense amount of incoming information that greatly exceeds the brain's processing capacity. Because of this fundamental limitation, the ability to suppress irrelevant information is a key determinant of perceptual efficiency. Here, I will review a series of studies investigating suppressive mechanisms in visual motion processing, namely perceptual suppression of large, background-like motions. These spatial suppression mechanisms are adaptive, operating only when sensory inputs are sufficiently robust to guarantee visibility. Converging correlational and causal evidence links these behavioral results with inhibitory center-surround mechanisms, namely those in cortical area MT. Spatial suppression is abnormally weak in several special populations, including the elderly and individuals with schizophrenia-a deficit that is evidenced by better-than-normal direction discriminations of large moving stimuli. Theoretical work shows that this abnormal weakening of spatial suppression should result in motion segregation deficits, but direct behavioral support of this hypothesis is lacking. Finally, I will argue that the ability to suppress information is a fundamental neural process that applies not only to perception but also to cognition in general. Supporting this argument, I will discuss recent research that shows individual differences in spatial suppression of motion signals strongly predict individual variations in IQ scores. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Long-term effects of serial anodal tDCS on motion perception in subjects with occipital stroke measured in the unaffected visual hemifield

    Directory of Open Access Journals (Sweden)

    Manuel C Olma

    2013-06-01

    Full Text Available Transcranial direct current stimulation (tDCS is a novel neuromodulatory tool that has seen early transition to clinical trials, although the high variability of these findings necessitates further studies in clincally-relevant populations. The majority of evidence into effects of repeated tDCS is based on research in the human motor system, but it is unclear whether the long-term effects of serial tDCS are motor-specific or transferable to other brain areas. This study aimed to examine whether serial anodal tDCS over the visual cortex can exogenously induce long-term neuroplastic changes in the visual cortex. However, when the visual cortex is affected by a cortical lesion, up-regulated endogenous neuroplastic adaptation processes may alter the susceptibility to tDCS. To this end, motion perception was investigated in the unaffected hemifield of subjects with unilateral visual cortex lesions. Twelve subjects with occipital ischaemic lesions participated in a within-subject, sham-controlled, double-blind study. MRI-registered sham or anodal tDCS (1.5 mA, 20 minutes was applied on five consecutive days over the visual cortex. Motion perception was tested before and after stimulation sessions and at 14- and 28-day follow-up. After a 16-day interval an identical study block with the other stimulation condition (anodal or sham tDCS followed. Serial anodal tDCS over the visual cortex resulted in an improvement in motion perception, a function attributed to MT/V5. This effect was still measurable at 14- and 28-day follow-up measurements. Thus, this may represent evidence for long-term tDCS-induced plasticity and has implications for the design of studies examining the time course of tDCS effects in both the visual and motor systems.

  12. Artificial Vision, New Visual Modalities and Neuroadaptation

    Directory of Open Access Journals (Sweden)

    Hilmi Or

    2012-01-01

    Full Text Available To study the descriptions from which artificial vision derives, to explore the new visual modalities resulting from eye surgeries and diseases, and to gain awareness of the use of machine vision systems for both enhancement of visual perception and better understanding of neuroadaptation. Science could not define until today what vision is. However, some optical-based systems and definitions have been established considering some factors for the formation of seeing. The best known system includes Gabor filter and Gabor patch which work on edge perception, describing the visual perception in the best known way. These systems are used today in industry and technology of machines, robots and computers to provide their "seeing". These definitions are used beyond the machinery in humans for neuroadaptation in new visual modalities after some eye surgeries or to improve the quality of some already known visual modalities. Beside this, “the blindsight” -which was not known to exist until 35 years ago - can be stimulated with visual exercises. Gabor system is a description of visual perception definable in machine vision as well as in human visual perception. This system is used today in robotic vision. There are new visual modalities which arise after some eye surgeries or with the use of some visual optical devices. Also, blindsight is a different visual modality starting to be defined even though the exact etiology is not known. In all the new visual modalities, new vision stimulating therapies using the Gabor systems can be applied. (Turk J Oph thal mol 2012; 42: 61-5

  13. Visual Motion Perception

    Science.gov (United States)

    1991-08-15

    displace- ment limit for motion in random dots," Vision Res., 24, 293-300. Pantie , A. & K. Turano (1986) "Direct comparisons of apparent motions...Hicks & AJ, Pantie (1978) "Apparent movement of successively generated subjec. uve figures," Perception, 7, 371-383. Ramachandran. V.S. & S.M. Anstis...thanks think deaf girl until world uncle flag home talk finish short thee our screwdiver sonry flower wrCstlir~g plan week wait accident guilty tree

  14. Why people see things that are not there: a novel Perception and Attention Deficit model for recurrent complex visual hallucinations.

    Science.gov (United States)

    Collerton, Daniel; Perry, Elaine; McKeith, Ian

    2005-12-01

    As many as two million people in the United Kingdom repeatedly see people, animals, and objects that have no objective reality. Hallucinations on the border of sleep, dementing illnesses, delirium, eye disease, and schizophrenia account for 90% of these. The remainder have rarer disorders. We review existing models of recurrent complex visual hallucinations (RCVH) in the awake person, including cortical irritation, cortical hyperexcitability and cortical release, top-down activation, misperception, dream intrusion, and interactive models. We provide evidence that these can neither fully account for the phenomenology of RCVH, nor for variations in the frequency of RCVH in different disorders. We propose a novel Perception and Attention Deficit (PAD) model for RCVH. A combination of impaired attentional binding and poor sensory activation of a correct proto-object, in conjunction with a relatively intact scene representation, bias perception to allow the intrusion of a hallucinatory proto-object into a scene perception. Incorporation of this image into a context-specific hallucinatory scene representation accounts for repetitive hallucinations. We suggest that these impairments are underpinned by disturbances in a lateral frontal cortex-ventral visual stream system. We show how the frequency of RCVH in different diseases is related to the coexistence of attentional and visual perceptual impairments; how attentional and perceptual processes can account for their phenomenology; and that diseases and other states with high rates of RCVH have cholinergic dysfunction in both frontal cortex and the ventral visual stream. Several tests of the model are indicated, together with a number of treatment options that it generates.

  15. Visual-vestibular interaction in motion perception

    NARCIS (Netherlands)

    Hosman, Ruud J A W; Cardullo, Frank M.; Bos, Jelte E.

    2011-01-01

    Correct perception of self motion is of vital importance for both the control of our position and posture when moving around in our environment. With the development of human controlled vehicles as bicycles, cars and aircraft motion perception became of interest for the understanding of vehicle

  16. Tornado Warning Perception and Response: Integrating the Roles of Visual Design, Demographics, and Hazard Experience.

    Science.gov (United States)

    Schumann, Ronald L; Ash, Kevin D; Bowser, Gregg C

    2018-02-01

    Recent advancements in severe weather detection and warning dissemination technologies have reduced, but not eliminated, large-casualty tornado hazards in the United States. Research on warning cognition and behavioral response by the public has the potential to further reduce tornado-related deaths and injuries; however, less research has been conducted in this area compared to tornado research in the physical sciences. Extant research in this vein tends to bifurcate. One branch of studies derives from classic risk perception, which investigates cognitive, affective, and sociocultural factors in relation to concern and preparation for uncertain risks. Another branch focuses on psychological, social, and cultural factors implicated in warning response for rapid onset hazards, with attention paid to previous experience and message design. Few studies link risk perceptions with cognition and response as elicited by specific examples of warnings. The present study unites risk perception, cognition, and response approaches by testing the contributions of hypothesized warning response drivers in one set of path models. Warning response is approximated by perceived fear and intended protective action as reported by survey respondents when exposed to hypothetical tornado warning scenarios. This study considers the roles of hazard knowledge acquisition, information-seeking behaviors, previous experience, and sociodemographic factors while controlling for the effects of the visual warning graphic. Findings from the study indicate the primacy of a user's visual interpretation of a warning graphic in shaping tornado warning response. Results also suggest that information-seeking habits, previous tornado experience, and local disaster culture play strong influencing roles in warning response. © 2017 Society for Risk Analysis.

  17. VGC analyzer: a software for statistical analysis of fully crossed multiple-reader multiple-case visual grading characteristics studies

    International Nuclear Information System (INIS)

    Baath, Magnus; Hansson, Jonny

    2016-01-01

    Visual grading characteristics (VGC) analysis is a non-parametric rank-invariant method for analysis of visual grading data. In VGC analysis, image quality ratings for two different conditions are compared by producing a VGC curve, similar to how the ratings for normal and abnormal cases in receiver operating characteristic (ROC) analysis are used to create an ROC curve. The use of established ROC software for the analysis of VGC data has therefore previously been proposed. However, the ROC analysis is based on the assumption of independence between normal and abnormal cases. In VGC analysis, this independence cannot always be assumed, e.g. if the ratings are based on the same patients imaged under both conditions. A dedicated software intended for analysis of VGC studies, which takes possible dependencies between ratings into account in the statistical analysis of a VGC study, has therefore been developed. The software-VGC Analyzer-determines the area under the VGC curve and its uncertainty using non-parametric re-sampling techniques. This article gives an introduction to VGC Analyzer, describes the types of analyses that can be performed and instructs the user about the input and output data. (authors)

  18. Embodied Perception: A Proposal to Reconcile Affordance and Spatial Perception

    OpenAIRE

    Ca?al-Bruland, Rouwen; van der Kamp, John

    2015-01-01

    Proffitt's embodied approach to perception is deeply indebted to Gibson's ecological approach to visual perception, in particular the idea that the primary objects of perception are affordances or what the environment offers for action. Yet, rather than directly addressing affordance perception, most of the empirical work evaluating Proffitt's approach focuses on the perception of spatial properties of the environment. We propose that theoretical and empirical efforts should be directed towar...

  19. 3D Shape Perception in Posterior Cortical Atrophy: A Visual Neuroscience Perspective

    Science.gov (United States)

    Gillebert, Céline R.; Schaeverbeke, Jolien; Bastin, Christine; Neyens, Veerle; Bruffaerts, Rose; De Weer, An-Sofie; Seghers, Alexandra; Sunaert, Stefan; Van Laere, Koen; Versijpt, Jan; Vandenbulcke, Mathieu; Salmon, Eric; Todd, James T.; Orban, Guy A.

    2015-01-01

    Posterior cortical atrophy (PCA) is a rare focal neurodegenerative syndrome characterized by progressive visuoperceptual and visuospatial deficits, most often due to atypical Alzheimer's disease (AD). We applied insights from basic visual neuroscience to analyze 3D shape perception in humans affected by PCA. Thirteen PCA patients and 30 matched healthy controls participated, together with two patient control groups with diffuse Lewy body dementia (DLBD) and an amnestic-dominant phenotype of AD, respectively. The hierarchical study design consisted of 3D shape processing for 4 cues (shading, motion, texture, and binocular disparity) with corresponding 2D and elementary feature extraction control conditions. PCA and DLBD exhibited severe 3D shape-processing deficits and AD to a lesser degree. In PCA, deficient 3D shape-from-shading was associated with volume loss in the right posterior inferior temporal cortex. This region coincided with a region of functional activation during 3D shape-from-shading in healthy controls. In PCA patients who performed the same fMRI paradigm, response amplitude during 3D shape-from-shading was reduced in this region. Gray matter volume in this region also correlated with 3D shape-from-shading in AD. 3D shape-from-disparity in PCA was associated with volume loss slightly more anteriorly in posterior inferior temporal cortex as well as in ventral premotor cortex. The findings in right posterior inferior temporal cortex and right premotor cortex are consistent with neurophysiologically based models of the functional anatomy of 3D shape processing. However, in DLBD, 3D shape deficits rely on mechanisms distinct from inferior temporal structural integrity. SIGNIFICANCE STATEMENT Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by progressive visuoperceptual dysfunction and most often an atypical presentation of Alzheimer's disease (AD) affecting the ventral and dorsal visual streams rather than the medial

  20. 3D Shape Perception in Posterior Cortical Atrophy: A Visual Neuroscience Perspective.

    Science.gov (United States)

    Gillebert, Céline R; Schaeverbeke, Jolien; Bastin, Christine; Neyens, Veerle; Bruffaerts, Rose; De Weer, An-Sofie; Seghers, Alexandra; Sunaert, Stefan; Van Laere, Koen; Versijpt, Jan; Vandenbulcke, Mathieu; Salmon, Eric; Todd, James T; Orban, Guy A; Vandenberghe, Rik

    2015-09-16

    Posterior cortical atrophy (PCA) is a rare focal neurodegenerative syndrome characterized by progressive visuoperceptual and visuospatial deficits, most often due to atypical Alzheimer's disease (AD). We applied insights from basic visual neuroscience to analyze 3D shape perception in humans affected by PCA. Thirteen PCA patients and 30 matched healthy controls participated, together with two patient control groups with diffuse Lewy body dementia (DLBD) and an amnestic-dominant phenotype of AD, respectively. The hierarchical study design consisted of 3D shape processing for 4 cues (shading, motion, texture, and binocular disparity) with corresponding 2D and elementary feature extraction control conditions. PCA and DLBD exhibited severe 3D shape-processing deficits and AD to a lesser degree. In PCA, deficient 3D shape-from-shading was associated with volume loss in the right posterior inferior temporal cortex. This region coincided with a region of functional activation during 3D shape-from-shading in healthy controls. In PCA patients who performed the same fMRI paradigm, response amplitude during 3D shape-from-shading was reduced in this region. Gray matter volume in this region also correlated with 3D shape-from-shading in AD. 3D shape-from-disparity in PCA was associated with volume loss slightly more anteriorly in posterior inferior temporal cortex as well as in ventral premotor cortex. The findings in right posterior inferior temporal cortex and right premotor cortex are consistent with neurophysiologically based models of the functional anatomy of 3D shape processing. However, in DLBD, 3D shape deficits rely on mechanisms distinct from inferior temporal structural integrity. Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by progressive visuoperceptual dysfunction and most often an atypical presentation of Alzheimer's disease (AD) affecting the ventral and dorsal visual streams rather than the medial temporal system. We applied

  1. Flow visualization

    CERN Document Server

    Merzkirch, Wolfgang

    1974-01-01

    Flow Visualization describes the most widely used methods for visualizing flows. Flow visualization evaluates certain properties of a flow field directly accessible to visual perception. Organized into five chapters, this book first presents the methods that create a visible flow pattern that could be investigated by visual inspection, such as simple dye and density-sensitive visualization methods. It then deals with the application of electron beams and streaming birefringence. Optical methods for compressible flows, hydraulic analogy, and high-speed photography are discussed in other cha

  2. The Open Space Sculptures Used in the Gençlik Park towards Visual Perception of Park Users

    Directory of Open Access Journals (Sweden)

    Ahmet Polat

    2012-11-01

    Full Text Available Urban parks are the most important areas that allow recreational activities in our towns. Increasing the visual quality of urban parks provides positive impacts on urban quality. Besides the artistic and technical features of open space sculptures which are used for urban park designs are the visual perceptions and preferences of park users are also important. In the context of this study, six sculptures in Gençlik Park which is in the boundaries Ankara have been considered. The aim of the study, to measure the visual quality of the sculptures in the urban parks through park users and to reveal the relationship between visual landscape indicators (of being interesting, coherence, complexity, meaningfulness, and mystery and the visual quality. For this purpose, the six pieces in Ankara Youth Park of sculpture were evaluated the scope of research. According to the results of the study; it was realized that park users like sculptures visually. A statistically significant relationship was found between the visual quality of the sculptures and some landscape indicators (to be interesting, mystery and harmony. In addition to these, some suggestions were made regarding the use of sculptures in urban parks.

  3. The effect of historical, non-fiction, trade books on third-grade students' perceptions of scientists

    Science.gov (United States)

    Farland, Donna Lynn

    Researchers do not know what, if any, specific influence such stereotypical images have on the shaping of children's perceptions in science (Schibeci & Sorenson, 1983), but the indications are that stereotypical images translate into negative perceptions of science. Commonly held stereotypic images are in direct opposition to what students should understand about science as identified by the National Science Education Standards (1996) in which learning about 'Science as a Human Endeavor' begins as early as grades K--4. Nationally, many schools are moving toward kit-based science instruction, which generally consists of a series of guided discovery activities that lead children toward description and understanding of scientific phenomena. It is proposed that by supplementing these kits with historical, non-fiction, trade books, children will gain a broader understanding of the diversity of scientists, their work, and the variety of places science is done. No studies, to date, have been conducted to examine students' understanding of the concepts included in 'Science as a Human Endeavor' as they receive kit-based science instruction. This research has been designed to answer the following question: Does the inclusion of historical, non-fiction, trade books, presenting scientists as people working with or developing an idea, as part of kit-based science instruction influence third grade students' representations of the contemporary scientist and his/her work? It was found that students who were read historical, non-fiction, trade books in conjunction with kit-based instruction demonstrated significant differences in their drawings of scientists from those produced by students who were not exposed to the trade books with respect to two criteria; appearance of scientists, and the activity performed by scientists. This study also revealed that students were able to maintain the improvement in their representations of scientists four weeks after the intervention had ended

  4. GABA shapes the dynamics of bistable perception.

    Science.gov (United States)

    van Loon, Anouk M; Knapen, Tomas; Scholte, H Steven; St John-Saaltink, Elexa; Donner, Tobias H; Lamme, Victor A F

    2013-05-06

    Sometimes, perception fluctuates spontaneously between two distinct interpretations of a constant sensory input. These bistable perceptual phenomena provide a unique window into the neural mechanisms that create the contents of conscious perception. Models of bistable perception posit that mutual inhibition between stimulus-selective neural populations in visual cortex plays a key role in these spontaneous perceptual fluctuations. However, a direct link between neural inhibition and bistable perception has not yet been established experimentally. Here, we link perceptual dynamics in three distinct bistable visual illusions (binocular rivalry, motion-induced blindness, and structure from motion) to measurements of gamma-aminobutyric acid (GABA) concentrations in human visual cortex (as measured with magnetic resonance spectroscopy) and to pharmacological stimulation of the GABAA receptor by means of lorazepam. As predicted by a model of neural interactions underlying bistability, both higher GABA concentrations in visual cortex and lorazepam administration induced slower perceptual dynamics, as reflected in a reduced number of perceptual switches and a lengthening of percept durations. Thus, we show that GABA, the main inhibitory neurotransmitter, shapes the dynamics of bistable perception. These results pave the way for future studies into the competitive neural interactions across the visual cortical hierarchy that elicit conscious perception. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Time-resolved influences of functional DAT1 and COMT variants on visual perception and post-processing.

    Directory of Open Access Journals (Sweden)

    Stephan Bender

    Full Text Available BACKGROUND: Dopamine plays an important role in orienting and the regulation of selective attention to relevant stimulus characteristics. Thus, we examined the influences of functional variants related to dopamine inactivation in the dopamine transporter (DAT1 and catechol-O-methyltransferase genes (COMT on the time-course of visual processing in a contingent negative variation (CNV task. METHODS: 64-channel EEG recordings were obtained from 195 healthy adolescents of a community-based sample during a continuous performance task (A-X version. Early and late CNV as well as preceding visual evoked potential components were assessed. RESULTS: Significant additive main effects of DAT1 and COMT on the occipito-temporal early CNV were observed. In addition, there was a trend towards an interaction between the two polymorphisms. Source analysis showed early CNV generators in the ventral visual stream and in frontal regions. There was a strong negative correlation between occipito-temporal visual post-processing and the frontal early CNV component. The early CNV time interval 500-1000 ms after the visual cue was specifically affected while the preceding visual perception stages were not influenced. CONCLUSIONS: Late visual potentials allow the genomic imaging of dopamine inactivation effects on visual post-processing. The same specific time-interval has been found to be affected by DAT1 and COMT during motor post-processing but not motor preparation. We propose the hypothesis that similar dopaminergic mechanisms modulate working memory encoding in both the visual and motor and perhaps other systems.

  6. How Strong Is Your Coffee? The Influence of Visual Metaphors and Textual Claims on Consumers' Flavor Perception and Product Evaluation.

    Science.gov (United States)

    Fenko, Anna; de Vries, Roxan; van Rompay, Thomas

    2018-01-01

    This study investigates the relative impact of textual claims and visual metaphors displayed on the product's package on consumers' flavor experience and product evaluation. For consumers, strength is one of the most important sensory attributes of coffee. The 2 × 3 between-subjects experiment ( N = 123) compared the effects of visual metaphor of strength (an image of a lion located either on top or on the bottom of the package of coffee beans) and the direct textual claim ("extra strong") on consumers' responses to coffee, including product expectation, flavor evaluation, strength perception and purchase intention. The results demonstrate that both the textual claim and the visual metaphor can be efficient in communicating the product attribute of strength. The presence of the image positively influenced consumers' product expectations before tasting. The textual claim increased the perception of strength of coffee and the purchase intention of the product. The location of the image also played an important role in flavor perception and purchase intention. The image located on the bottom of the package increased the perceived strength of coffee and purchase intention of the product compared to the image on top of the package. This result could be interpreted from the perspective of the grounded cognition theory, which suggests that a picture in the lower part of the package would automatically activate the "strong is heavy" metaphor. As heavy objects are usually associated with a position on the ground, this would explain why perceiving a visually heavy package would lead to the experience of a strong coffee. Further research is needed to better understand the relationships between a metaphorical image and its spatial position in food packaging design.

  7. Hyperbolic planforms in relation to visual edges and textures perception.

    Directory of Open Access Journals (Sweden)

    Pascal Chossat

    2009-12-01

    Full Text Available We propose to use bifurcation theory and pattern formation as theoretical probes for various hypotheses about the neural organization of the brain. This allows us to make predictions about the kinds of patterns that should be observed in the activity of real brains through, e.g., optical imaging, and opens the door to the design of experiments to test these hypotheses. We study the specific problem of visual edges and textures perception and suggest that these features may be represented at the population level in the visual cortex as a specific second-order tensor, the structure tensor, perhaps within a hypercolumn. We then extend the classical ring model to this case and show that its natural framework is the non-Euclidean hyperbolic geometry. This brings in the beautiful structure of its group of isometries and certain of its subgroups which have a direct interpretation in terms of the organization of the neural populations that are assumed to encode the structure tensor. By studying the bifurcations of the solutions of the structure tensor equations, the analog of the classical Wilson and Cowan equations, under the assumption of invariance with respect to the action of these subgroups, we predict the appearance of characteristic patterns. These patterns can be described by what we call hyperbolic or H-planforms that are reminiscent of Euclidean planar waves and of the planforms that were used in previous work to account for some visual hallucinations. If these patterns could be observed through brain imaging techniques they would reveal the built-in or acquired invariance of the neural organization to the action of the corresponding subgroups.

  8. Relationship between Stereoscopic Vision, Visual Perception, and Microstructure Changes of Corpus Callosum and Occipital White Matter in the 4-Year-Old Very Low Birth Weight Children

    Directory of Open Access Journals (Sweden)

    Przemko Kwinta

    2015-01-01

    Full Text Available Aim. To assess the relationship between stereoscopic vision, visual perception, and microstructure of the corpus callosum (CC and occipital white matter, 61 children born with a mean birth weight of 1024 g (SD 270 g were subjected to detailed ophthalmologic evaluation, Developmental Test of Visual Perception (DTVP-3, and diffusion tensor imaging (DTI at the age of 4. Results. Abnormal stereoscopic vision was detected in 16 children. Children with abnormal stereoscopic vision had smaller CC (CC length: 53±6 mm versus 61±4 mm; p<0.01; estimated CC area: 314±106 mm2 versus 446±79 mm2; p<0.01 and lower fractional anisotropy (FA values in CC (FA value of rostrum/genu: 0.7±0.09 versus 0.79±0.07; p<0.01; FA value of CC body: 0.74±0.13 versus 0.82±0.09; p=0.03. We found a significant correlation between DTVP-3 scores, CC size, and FA values in rostrum and body. This correlation was unrelated to retinopathy of prematurity. Conclusions. Visual perceptive dysfunction in ex-preterm children without major sequelae of prematurity depends on more subtle changes in the brain microstructure, including CC. Role of interhemispheric connections in visual perception might be more complex than previously anticipated.

  9. Perceptions Concerning Visual Culture Dialogues of Visual Art Pre-Service Teachers

    Science.gov (United States)

    Mamur, Nuray

    2012-01-01

    The visual art which is commented by the visual art teachers to help processing of the visual culture is important. In this study it is tried to describe the effect of visual culture based on the usual aesthetic experiences to be included in the learning process art education. The action research design, which is a qualitative study, is conducted…

  10. Relating Standardized Visual Perception Measures to Simulator Visual System Performance

    Science.gov (United States)

    Kaiser, Mary K.; Sweet, Barbara T.

    2013-01-01

    Human vision is quantified through the use of standardized clinical vision measurements. These measurements typically include visual acuity (near and far), contrast sensitivity, color vision, stereopsis (a.k.a. stereo acuity), and visual field periphery. Simulator visual system performance is specified in terms such as brightness, contrast, color depth, color gamut, gamma, resolution, and field-of-view. How do these simulator performance characteristics relate to the perceptual experience of the pilot in the simulator? In this paper, visual acuity and contrast sensitivity will be related to simulator visual system resolution, contrast, and dynamic range; similarly, color vision will be related to color depth/color gamut. Finally, we will consider how some characteristics of human vision not typically included in current clinical assessments could be used to better inform simulator requirements (e.g., relating dynamic characteristics of human vision to update rate and other temporal display characteristics).

  11. Early vision and visual attention

    Directory of Open Access Journals (Sweden)

    Gvozdenović Vasilije P.

    2003-01-01

    Full Text Available The question whether visual perception is spontaneous, sudden or is running through several phases, mediated by higher cognitive processes, was raised ever since the early work of Gestalt psychologists. In the early 1980s, Treisman proposed the feature integration theory of attention (FIT, based on the findings of neuroscience. Soon after publishing her theory a new scientific approach appeared investigating several visual perception phenomena. The most widely researched were the key constructs of FIT, like types of visual search and the role of the attention. The following review describes the main studies of early vision and visual attention.

  12. Visual perception of dynamic properties: cue heuristics versus direct-perceptual competence.

    Science.gov (United States)

    Runeson, S; Juslin, P; Olsson, H

    2000-07-01

    Constructivist and Gibsonian approaches disagree over the possibility of direct perceptual use of advanced information. A trenchant instance concerns visual perception of underlying dynamic properties as specified by kinematic patterns of events. For the paradigmatic task of discrimination of relative mass in observed collisions, 2 mathematical models are developed, 1 model representing a direct, invariant-based approach, and 1 representing a cue-heuristic approach. The models enable a critical experimental design with distinct predictions concerning performance data and confidence ratings. Although pretraining results were mixed, the invariant-based model was empirically confirmed after a minimal amount of training: Competence entails the use of advanced kinematic information in a direct-perceptual ("sensory") mode of apprehension, in contrast to beginners' use of simpler cues in an inferential ("cognitive") mode.

  13. Op art and visual perception.

    Science.gov (United States)

    Wade, N J

    1978-01-01

    An attempt is made to list the visual phenomena exploited in op art. These include moire frinlude moiré fringes, afterimages, Hermann grid effects, Gestalt grouping principles, blurring and movement due to astigmatic fluctuations in accommodation, scintillation and streaming possibly due to eye movements, and visual persistence. The historical origins of these phenomena are also noted.

  14. Testing the accuracy of timing reports in visual timing tasks with a consumer-grade digital camera.

    Science.gov (United States)

    Smyth, Rachael E; Oram Cardy, Janis; Purcell, David

    2017-06-01

    This study tested the accuracy of a visual timing task using a readily available and relatively inexpensive consumer grade digital camera. A visual inspection time task was recorded using short high-speed video clips and the timing as reported by the task's program was compared to the timing as recorded in the video clips. Discrepancies in these two timing reports were investigated further and based on display refresh rate, a decision was made whether the discrepancy was large enough to affect the results as reported by the task. In this particular study, the errors in timing were not large enough to impact the results of the study. The procedure presented in this article offers an alternative method for performing a timing test, which uses readily available hardware and can be used to test the timing in any software program on any operating system and display.

  15. Primary visual cortex activity along the apparent-motion trace reflects illusory perception.

    Directory of Open Access Journals (Sweden)

    Lars Muckli

    2005-08-01

    Full Text Available The illusion of apparent motion can be induced when visual stimuli are successively presented at different locations. It has been shown in previous studies that motion-sensitive regions in extrastriate cortex are relevant for the processing of apparent motion, but it is unclear whether primary visual cortex (V1 is also involved in the representation of the illusory motion path. We investigated, in human subjects, apparent-motion-related activity in patches of V1 representing locations along the path of illusory stimulus motion using functional magnetic resonance imaging. Here we show that apparent motion caused a blood-oxygenation-level-dependent response along the V1 representations of the apparent-motion path, including regions that were not directly activated by the apparent-motion-inducing stimuli. This response was unaltered when participants had to perform an attention-demanding task that diverted their attention away from the stimulus. With a bistable motion quartet, we confirmed that the activity was related to the conscious perception of movement. Our data suggest that V1 is part of the network that represents the illusory path of apparent motion. The activation in V1 can be explained either by lateral interactions within V1 or by feedback mechanisms from higher visual areas, especially the motion-sensitive human MT/V5 complex.

  16. Stretch-sensitive paresis and effort perception in hemiparesis.

    Science.gov (United States)

    Vinti, Maria; Bayle, Nicolas; Hutin, Emilie; Burke, David; Gracies, Jean-Michel

    2015-08-01

    In spastic paresis, stretch applied to the antagonist increases its inappropriate recruitment during agonist command (spastic co-contraction). It is unknown whether antagonist stretch: (1) also affects agonist recruitment; (2) alters effort perception. We quantified voluntary activation of ankle dorsiflexors, effort perception, and plantar flexor co-contraction during graded dorsiflexion efforts at two gastrocnemius lengths. Eighteen healthy (age 41 ± 13) and 18 hemiparetic (age 54 ± 12) subjects performed light, medium and maximal isometric dorsiflexion efforts with the knee flexed or extended. We determined dorsiflexor torque, Root Mean Square EMG and Agonist Recruitment/Co-contraction Indices (ARI/CCI) from the 500 ms peak voluntary agonist recruitment in a 5-s maximal isometric effort in tibialis anterior, soleus and medial gastrocnemius. Subjects retrospectively reported effort perception on a 10-point visual analog scale. During gastrocnemius stretch in hemiparetic subjects, we observed: (1) a 25 ± 7 % reduction of tibialis anterior voluntary activation (maximum reduction 98 %; knee extended vs knee flexed; p = 0.007, ANOVA); (2) an increase in dorsiflexion effort perception (p = 0.03, ANCOVA). Such changes did not occur in healthy subjects. Effort perception depended on tibialis anterior recruitment only (βARI(TA) = 0.61, p hemiparesis, voluntary ability to recruit agonist motoneurones is impaired--sometimes abolished--by antagonist stretch, a phenomenon defined here as stretch-sensitive paresis. In addition, spastic co-contraction increases effort perception, an additional incentive to evaluate and treat this phenomenon.

  17. 3D Visualization Types in Multimedia Applications for Science Learning: A Case Study for 8th Grade Students in Greece

    Science.gov (United States)

    Korakakis, G.; Pavlatou, E. A.; Palyvos, J. A.; Spyrellis, N.

    2009-01-01

    This research aims to determine whether the use of specific types of visualization (3D illustration, 3D animation, and interactive 3D animation) combined with narration and text, contributes to the learning process of 13- and 14- years-old students in science courses. The study was carried out with 212 8th grade students in Greece. This…

  18. Functional dissociation between action and perception of object shape in developmental visual object agnosia.

    Science.gov (United States)

    Freud, Erez; Ganel, Tzvi; Avidan, Galia; Gilaie-Dotan, Sharon

    2016-03-01

    According to the two visual systems model, the cortical visual system is segregated into a ventral pathway mediating object recognition, and a dorsal pathway mediating visuomotor control. In the present study we examined whether the visual control of action could develop normally even when visual perceptual abilities are compromised from early childhood onward. Using his fingers, LG, an individual with a rare developmental visual object agnosia, manually estimated (perceptual condition) the width of blocks that varied in width and length (but not in overall size), or simply picked them up across their width (grasping condition). LG's perceptual sensitivity to target width was profoundly impaired in the manual estimation task compared to matched controls. In contrast, the sensitivity to object shape during grasping, as measured by maximum grip aperture (MGA), the time to reach the MGA, the reaction time and the total movement time were all normal in LG. Further analysis, however, revealed that LG's sensitivity to object shape during grasping emerged at a later time stage during the movement compared to controls. Taken together, these results demonstrate a dissociation between action and perception of object shape, and also point to a distinction between different stages of the grasping movement, namely planning versus online control. Moreover, the present study implies that visuomotor abilities can develop normally even when perceptual abilities developed in a profoundly impaired fashion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Perceiving groups: The people perception of diversity and hierarchy.

    Science.gov (United States)

    Phillips, L Taylor; Slepian, Michael L; Hughes, Brent L

    2018-05-01

    The visual perception of individuals has received considerable attention (visual person perception), but little social psychological work has examined the processes underlying the visual perception of groups of people (visual people perception). Ensemble-coding is a visual mechanism that automatically extracts summary statistics (e.g., average size) of lower-level sets of stimuli (e.g., geometric figures), and also extends to the visual perception of groups of faces. Here, we consider whether ensemble-coding supports people perception, allowing individuals to form rapid, accurate impressions about groups of people. Across nine studies, we demonstrate that people visually extract high-level properties (e.g., diversity, hierarchy) that are unique to social groups, as opposed to individual persons. Observers rapidly and accurately perceived group diversity and hierarchy, or variance across race, gender, and dominance (Studies 1-3). Further, results persist when observers are given very short display times, backward pattern masks, color- and contrast-controlled stimuli, and absolute versus relative response options (Studies 4a-7b), suggesting robust effects supported specifically by ensemble-coding mechanisms. Together, we show that humans can rapidly and accurately perceive not only individual persons, but also emergent social information unique to groups of people. These people perception findings demonstrate the importance of visual processes for enabling people to perceive social groups and behave effectively in group-based social interactions. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  20. Holistic face categorization in higher-level cortical visual areas of the normal and prosopagnosic brain: towards a non-hierarchical view of face perception

    Directory of Open Access Journals (Sweden)

    Bruno Rossion

    2011-01-01

    Full Text Available How a visual stimulus is initially categorized as a face in a network of human brain areas remains largely unclear. Hierarchical neuro-computational models of face perception assume that the visual stimulus is first decomposed in local parts in lower order visual areas. These parts would then be combined into a global representation in higher order face-sensitive areas of the occipito-temporal cortex. Here we tested this view in fMRI with visual stimuli that are categorized as faces based on their global configuration rather than their local parts (2-tones Mooney figures and Arcimboldo’s facelike paintings. Compared to the same inverted visual stimuli that are not categorized as faces, these stimuli activated the right middle fusiform gyrus (Fusiform face area, FFA and superior temporal sulcus (pSTS, with no significant activation in the posteriorly located inferior occipital gyrus (i.e., no occipital face area, OFA. This observation is strengthened by behavioral and neural evidence for normal face categorization of these stimuli in a brain-damaged prosopagnosic patient (PS whose intact right middle fusiform gyrus and superior temporal sulcus are devoid of any potential face-sensitive inputs from the lesioned right inferior occipital cortex. Together, these observations indicate that face-preferential activation may emerge in higher order visual areas of the right hemisphere without any face-preferential inputs from lower order visual areas, supporting a non-hierarchical view of face perception in the visual cortex.

  1. Impact of convenience void in a bladder diary with urinary perception grade to assess overactive bladder symptoms: a community-based study.

    Science.gov (United States)

    Honjo, Hisashi; Kawauchi, Akihiro; Nakao, Masahiro; Ukimura, Osamu; Kitakoji, Hiroshi; Miki, Tsuneharu

    2010-09-01

    Bladder diaries including bladder perception grade were analyzed to assess convenience void (CV) in community-dwelling women 40 years of age or older. A total of 310 women completed a 3-day bladder diary with a grade for bladder perception. The grade was defined on scores 0-5 as follows: 0 = No bladder sensation, 1 = Sensation of bladder filling without desire to void, 2 = Desire to void, 3 = Strong desire to void, 4 = Urgency without urge urinary incontinence (UUI), and 5 = Urge incontinence episode. CV was defined as void without desire to void: when the grade was 0, CV in a narrow sense, and when 0 or 1, CV in a broad sense. The incidence of CV in the broad sense significantly decreased with age. Of the 310 women, 48 (15.5%) had overactive bladder (OAB) symptoms on the medical interview, including 37 (11.9%) without UUI (OAB-Dry) and 11 (3.5%) with UUI (OAB-Wet). Of the remaining 262 women, 111 (35.8%), who had urgency but a urinary frequency of 7 or less, and another 141 (48.7%) were classified into the Normal with Urgency and Normal without Urgency groups, respectively. The incidence of CV in a broad sense in the Normal without Urgency group was significantly greater than that in the Normal with Urgency and OAB-Wet groups. The mean voided volumes of CV in the broad sense in the OAB-Wet group were significantly smaller than those in the other three groups. The evaluation of CV may be a new tool in assessing storage condition and voiding dysfunction. © 2010 Wiley-Liss, Inc.

  2. Visual Control of Locomotion

    National Research Council Canada - National Science Library

    Loomis, Jack M; Beall, Andrew C

    2005-01-01

    The accomplishments were threefold. First, a software tool for rendering virtual environments was developed, a tool useful for other researchers interested in visual perception and visual control of action...

  3. Continued use of an interactive computer game-based visual perception learning system in children with developmental delay.

    Science.gov (United States)

    Lin, Hsien-Cheng; Chiu, Yu-Hsien; Chen, Yenming J; Wuang, Yee-Pay; Chen, Chiu-Ping; Wang, Chih-Chung; Huang, Chien-Ling; Wu, Tang-Meng; Ho, Wen-Hsien

    2017-11-01

    This study developed an interactive computer game-based visual perception learning system for special education children with developmental delay. To investigate whether perceived interactivity affects continued use of the system, this study developed a theoretical model of the process in which learners decide whether to continue using an interactive computer game-based visual perception learning system. The technology acceptance model, which considers perceived ease of use, perceived usefulness, and perceived playfulness, was extended by integrating perceived interaction (i.e., learner-instructor interaction and learner-system interaction) and then analyzing the effects of these perceptions on satisfaction and continued use. Data were collected from 150 participants (rehabilitation therapists, medical paraprofessionals, and parents of children with developmental delay) recruited from a single medical center in Taiwan. Structural equation modeling and partial-least-squares techniques were used to evaluate relationships within the model. The modeling results indicated that both perceived ease of use and perceived usefulness were positively associated with both learner-instructor interaction and learner-system interaction. However, perceived playfulness only had a positive association with learner-system interaction and not with learner-instructor interaction. Moreover, satisfaction was positively affected by perceived ease of use, perceived usefulness, and perceived playfulness. Thus, satisfaction positively affects continued use of the system. The data obtained by this study can be applied by researchers, designers of computer game-based learning systems, special education workers, and medical professionals. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. How Strong Is Your Coffee? The Influence of Visual Metaphors and Textual Claims on Consumers’ Flavor Perception and Product Evaluation

    Science.gov (United States)

    Fenko, Anna; de Vries, Roxan; van Rompay, Thomas

    2018-01-01

    This study investigates the relative impact of textual claims and visual metaphors displayed on the product’s package on consumers’ flavor experience and product evaluation. For consumers, strength is one of the most important sensory attributes of coffee. The 2 × 3 between-subjects experiment (N = 123) compared the effects of visual metaphor of strength (an image of a lion located either on top or on the bottom of the package of coffee beans) and the direct textual claim (“extra strong”) on consumers’ responses to coffee, including product expectation, flavor evaluation, strength perception and purchase intention. The results demonstrate that both the textual claim and the visual metaphor can be efficient in communicating the product attribute of strength. The presence of the image positively influenced consumers’ product expectations before tasting. The textual claim increased the perception of strength of coffee and the purchase intention of the product. The location of the image also played an important role in flavor perception and purchase intention. The image located on the bottom of the package increased the perceived strength of coffee and purchase intention of the product compared to the image on top of the package. This result could be interpreted from the perspective of the grounded cognition theory, which suggests that a picture in the lower part of the package would automatically activate the “strong is heavy” metaphor. As heavy objects are usually associated with a position on the ground, this would explain why perceiving a visually heavy package would lead to the experience of a strong coffee. Further research is needed to better understand the relationships between a metaphorical image and its spatial position in food packaging design. PMID:29459840

  5. How Strong Is Your Coffee? The Influence of Visual Metaphors and Textual Claims on Consumers’ Flavor Perception and Product Evaluation

    Directory of Open Access Journals (Sweden)

    Anna Fenko

    2018-02-01

    Full Text Available This study investigates the relative impact of textual claims and visual metaphors displayed on the product’s package on consumers’ flavor experience and product evaluation. For consumers, strength is one of the most important sensory attributes of coffee. The 2 × 3 between-subjects experiment (N = 123 compared the effects of visual metaphor of strength (an image of a lion located either on top or on the bottom of the package of coffee beans and the direct textual claim (“extra strong” on consumers’ responses to coffee, including product expectation, flavor evaluation, strength perception and purchase intention. The results demonstrate that both the textual claim and the visual metaphor can be efficient in communicating the product attribute of strength. The presence of the image positively influenced consumers’ product expectations before tasting. The textual claim increased the perception of strength of coffee and the purchase intention of the product. The location of the image also played an important role in flavor perception and purchase intention. The image located on the bottom of the package increased the perceived strength of coffee and purchase intention of the product compared to the image on top of the package. This result could be interpreted from the perspective of the grounded cognition theory, which suggests that a picture in the lower part of the package would automatically activate the “strong is heavy” metaphor. As heavy objects are usually associated with a position on the ground, this would explain why perceiving a visually heavy package would lead to the experience of a strong coffee. Further research is needed to better understand the relationships between a metaphorical image and its spatial position in food packaging design.

  6. Age differences in visual-auditory self-motion perception during a simulated driving task

    Directory of Open Access Journals (Sweden)

    Robert eRamkhalawansingh

    2016-04-01

    Full Text Available Recent evidence suggests that visual-auditory cue integration may change as a function of age such that integration is heightened among older adults. Our goal was to determine whether these changes in multisensory integration are also observed in the context of self-motion perception under realistic task constraints. Thus, we developed a simulated driving paradigm in which we provided older and younger adults with visual motion cues (i.e. optic flow and systematically manipulated the presence or absence of congruent auditory cues to self-motion (i.e. engine, tire, and wind sounds. Results demonstrated that the presence or absence of congruent auditory input had different effects on older and younger adults. Both age groups demonstrated a reduction in speed variability when auditory cues were present compared to when they were absent, but older adults demonstrated a proportionally greater reduction in speed variability under combined sensory conditions. These results are consistent with evidence indicating that multisensory integration is heightened in older adults. Importantly, this study is the first to provide evidence to suggest that age differences in multisensory integration may generalize from simple stimulus detection tasks to the integration of the more complex and dynamic visual and auditory cues that are experienced during self-motion.

  7. Correction of Visual Perception Based on Neuro-Fuzzy Learning for the Humanoid Robot TEO

    Directory of Open Access Journals (Sweden)

    Juan Hernandez-Vicen

    2018-03-01

    Full Text Available New applications related to robotic manipulation or transportation tasks, with or without physical grasping, are continuously being developed. To perform these activities, the robot takes advantage of different kinds of perceptions. One of the key perceptions in robotics is vision. However, some problems related to image processing makes the application of visual information within robot control algorithms difficult. Camera-based systems have inherent errors that affect the quality and reliability of the information obtained. The need of correcting image distortion slows down image parameter computing, which decreases performance of control algorithms. In this paper, a new approach to correcting several sources of visual distortions on images in only one computing step is proposed. The goal of this system/algorithm is the computation of the tilt angle of an object transported by a robot, minimizing image inherent errors and increasing computing speed. After capturing the image, the computer system extracts the angle using a Fuzzy filter that corrects at the same time all possible distortions, obtaining the real angle in only one processing step. This filter has been developed by the means of Neuro-Fuzzy learning techniques, using datasets with information obtained from real experiments. In this way, the computing time has been decreased and the performance of the application has been improved. The resulting algorithm has been tried out experimentally in robot transportation tasks in the humanoid robot TEO (Task Environment Operator from the University Carlos III of Madrid.

  8. Determining student teachers' perceptions on using technology via Likert scale, visual association test and metaphors: A mixed study

    Directory of Open Access Journals (Sweden)

    Mevhibe Kobak

    2013-04-01

    Full Text Available The aim of this study is to determine senior student teachers’ perceptions on using technology by approaching various points of view. In this study, researchers collected data through Technology Perceptions Scale, Visual Association Activity and Technology Metaphors. The participants of the study were 104 senior student teachers who were enrolled in Balıkesir University Necatibey Faculty of Education. In this descriptive study, researchers interpreted qualitative data in conjunction with quantitative data. Based on the data obtained, even though student teachers’ perceptions on using technology were found positive in the light of Likert scale, there was no significant relation in terms of gender and enrolled undergraduate program. According to the results of visual association test, student teachers ranked smartboard, Internet and computer in the first three, and portable media player, mobile phone and video/camera in the last three. Besides, researchers analyzed and classified student teachers’ metaphors about technology under 9 categories: 1developing-changing technology, 2rapidly progressing technology, 3 limitless-endless technology, 4beneficial technology, 5harmful technology, 6both beneficial and harmful technology, 7indispensible technology, 8technology as a necessity, 9 all-inclusive technology. At the end of the study, those nine categories which were acquired using the content analysis technique are presented in a table which shows the interaction between categories in a holistic view.

  9. Commonalities between perception and cognition

    Directory of Open Access Journals (Sweden)

    Michela C. Tacca

    2011-11-01

    Full Text Available Perception and cognition are highly interrelated. Given the influence that these systems exert on one another, it is important to explain how perceptual representations and cognitive representations interact. In this paper, I analyze the similarities between visual perceptual representations and cognitive representations in terms of their structural properties and content. Specifically, I argue that the spatial structure underlying visual object representation displays systematicity—a property that is considered to be characteristic of propositional cognitive representations. To this end, I propose a logical characterization of visual feature binding as described by Treisman’s Feature Integration Theory and argue that systematicity is not only a property of language-like representations, but also of spatially organized visual representations. Furthermore, I argue that if systematicity is taken to be a criterion to distinguish between conceptual and nonconceptual representations, then visual representations, that display systematicity, might count as an early type of conceptual representations. Showing these analogies between visual perception and cognition is an important step towards understanding the interface between the two systems. The ideas here presented might also set the stage for new empirical studies that directly compare binding (and other relational operations in visual perception and higher cognition.

  10. Cortical response tracking the conscious experience of threshold duration visual stimuli indicates visual perception is all or none

    Science.gov (United States)

    Sekar, Krithiga; Findley, William M.; Poeppel, David; Llinás, Rodolfo R.

    2013-01-01

    At perceptual threshold, some stimuli are available for conscious access whereas others are not. Such threshold inputs are useful tools for investigating the events that separate conscious awareness from unconscious stimulus processing. Here, viewing unmasked, threshold-duration images was combined with recording magnetoencephalography to quantify differences among perceptual states, ranging from no awareness to ambiguity to robust perception. A four-choice scale was used to assess awareness: “didn’t see” (no awareness), “couldn’t identify” (awareness without identification), “unsure” (awareness with low certainty identification), and “sure” (awareness with high certainty identification). Stimulus-evoked neuromagnetic signals were grouped according to behavioral response choices. Three main cortical responses were elicited. The earliest response, peaking at ∼100 ms after stimulus presentation, showed no significant correlation with stimulus perception. A late response (∼290 ms) showed moderate correlation with stimulus awareness but could not adequately differentiate conscious access from its absence. By contrast, an intermediate response peaking at ∼240 ms was observed only for trials in which stimuli were consciously detected. That this signal was similar for all conditions in which awareness was reported is consistent with the hypothesis that conscious visual access is relatively sharply demarcated. PMID:23509248

  11. Micro-calibration of space and motion by photoreceptors synchronized in parallel with cortical oscillations: A unified theory of visual perception.

    Science.gov (United States)

    Jerath, Ravinder; Cearley, Shannon M; Barnes, Vernon A; Jensen, Mike

    2018-01-01

    A fundamental function of the visual system is detecting motion, yet visual perception is poorly understood. Current research has determined that the retina and ganglion cells elicit responses for motion detection; however, the underlying mechanism for this is incompletely understood. Previously we proposed that retinogeniculo-cortical oscillations and photoreceptors work in parallel to process vision. Here we propose that motion could also be processed within the retina, and not in the brain as current theory suggests. In this paper, we discuss: 1) internal neural space formation; 2) primary, secondary, and tertiary roles of vision; 3) gamma as the secondary role; and 4) synchronization and coherence. Movement within the external field is instantly detected by primary processing within the space formed by the retina, providing a unified view of the world from an internal point of view. Our new theory begins to answer questions about: 1) perception of space, erect images, and motion, 2) purpose of lateral inhibition, 3) speed of visual perception, and 4) how peripheral color vision occurs without a large population of cones located peripherally in the retina. We explain that strong oscillatory activity influences on brain activity and is necessary for: 1) visual processing, and 2) formation of the internal visuospatial area necessary for visual consciousness, which could allow rods to receive precise visual and visuospatial information, while retinal waves could link the lateral geniculate body with the cortex to form a neural space formed by membrane potential-based oscillations and photoreceptors. We propose that vision is tripartite, with three components that allow a person to make sense of the world, terming them "primary, secondary, and tertiary roles" of vision. Finally, we propose that Gamma waves that are higher in strength and volume allow communication among the retina, thalamus, and various areas of the cortex, and synchronization brings cortical

  12. Analysis of both perceptual and motor skills of children with dyslalia before their entering of the first grade of primary school

    OpenAIRE

    Pešlová, Markéta

    2015-01-01

    The thesis deals with an analysis of both perceptual and motor skills of children with dyslalia before their entering of the first grade of primary school. The aim of this thesis is to determine the level of perceptual and motor skills of both preschool children with dyslalia and intact children. The preschool age of a child is described in the theoretical part of the thesis. The thesis also defines dyslalia. Further chapters deal with auditory and visual perception. The area of motor skills ...

  13. Altered figure-ground perception in monkeys with an extra-striate lesion.

    Science.gov (United States)

    Supèr, Hans; Lamme, Victor A F

    2007-11-05

    The visual system binds and segments the elements of an image into coherent objects and their surroundings. Recent findings demonstrate that primary visual cortex is involved in this process of figure-ground organization. In the primary visual cortex the late part of a neural response to a stimulus correlates with figure-ground segregation and perception. Such a late onset indicates an involvement of feedback projections from higher visual areas. To investigate the possible role of feedback in figure-ground perception we removed dorsal extra-striate areas of the monkey visual cortex. The findings show that figure-ground perception is reduced when the figure is presented in the lesioned hemifield and perception is normal when the figure appeared in the intact hemifield. In conclusion, our observations show the importance for recurrent processing in visual perception.

  14. Wearing weighted backpack dilates subjective visual duration: The role of functional linkage between weight experience and visual timing

    Directory of Open Access Journals (Sweden)

    Lina eJia

    2015-09-01

    Full Text Available Bodily state plays a critical role in our perception. In the present study, we asked the question whether and how bodily experience of weights influences time perception. Participants judged durations of a picture (a backpack or a trolley bag presented on the screen, while wearing different weight backpacks or without backpack. The results showed that the subjective dura-tion of the backpack picture was dilated when participants wore a medium weighted backpack relative to an empty backpack or without backpack, regardless of identity (e.g., color of the visual backpack. However, the duration dilation was not manifested for the picture of trolley bag. These findings suggest that weight experience modulates visual duration estimation through the linkage between the wore backpack and to-be-estimated visual target. The con-gruent action affordance between the wore backpack and visual inputs plays a critical role in the functional linkage between inner experience and time perception. We interpreted our findings within the framework of embodied time perception.

  15. The Holistic Processing Account of Visual Expertise in Medical Image Perception: A Review.

    Science.gov (United States)

    Sheridan, Heather; Reingold, Eyal M

    2017-01-01

    In the field of medical image perception, the holistic processing perspective contends that experts can rapidly extract global information about the image, which can be used to guide their subsequent search of the image (Swensson, 1980; Nodine and Kundel, 1987; Kundel et al., 2007). In this review, we discuss the empirical evidence supporting three different predictions that can be derived from the holistic processing perspective: Expertise in medical image perception is domain-specific, experts use parafoveal and/or peripheral vision to process large regions of the image in parallel, and experts benefit from a rapid initial glimpse of an image. In addition, we discuss a pivotal recent study (Litchfield and Donovan, 2016) that seems to contradict the assumption that experts benefit from a rapid initial glimpse of the image. To reconcile this finding with the existing literature, we suggest that global processing may serve multiple functions that extend beyond the initial glimpse of the image. Finally, we discuss future research directions, and we highlight the connections between the holistic processing account and similar theoretical perspectives and findings from other domains of visual expertise.

  16. Vision as subjective perception

    International Nuclear Information System (INIS)

    Reppas, J.B.; Dale, A.; Sereno, M.; Tootell, R.

    1996-01-01

    The human brain is not very different of the monkey's one: at least, its visual cortex is organized as a similar scheme. Specialized areas in the movement analysis are found and others in the forms perception. In this work, the author tries to answer to the following questions: 1)why so many visual areas? What are exactly their role in vision? Thirteen years of experimentation have not allowed to answer to these questions. The cerebral NMR imaging gives the opportunity of understanding the subjective perception of the visual world. One step which is particularly described in this work is to know how the visual cortex reacts to the optical illusions. (O.M.)

  17. Reentrant processing in intuitive perception.

    Directory of Open Access Journals (Sweden)

    Phan Luu

    Full Text Available The process of perception requires not only the brain's receipt of sensory data but also the meaningful organization of that data in relation to the perceptual experience held in memory. Although it typically results in a conscious percept, the process of perception is not fully conscious. Research on the neural substrates of human visual perception has suggested that regions of limbic cortex, including the medial orbital frontal cortex (mOFC, may contribute to intuitive judgments about perceptual events, such as guessing whether an object might be present in a briefly presented fragmented drawing. Examining dense array measures of cortical electrical activity during a modified Waterloo Gestalt Closure Task, results show, as expected, that activity in medial orbital frontal electrical responses (about 250 ms was associated with intuitive judgments. Activity in the right temporal-parietal-occipital (TPO region was found to predict mOFC (approximately 150 ms activity and, in turn, was subsequently influenced by the mOFC at a later time (approximately 300 ms. The initial perception of gist or meaning of a visual stimulus in limbic networks may thus yield reentrant input to the visual areas to influence continued development of the percept. Before perception is completed, the initial representation of gist may support intuitive judgments about the ongoing perceptual process.

  18. Perception Enhancement using Visual Attributes in Sequence Motif Visualization

    OpenAIRE

    Oon, Yin; Lee, Nung; Kok, Wei

    2016-01-01

    Sequence logo is a well-accepted scientific method to visualize the conservation characteristics of biological sequence motifs. Previous studies found that using sequence logo graphical representation for scientific evidence reports or arguments could seriously cause biases and misinterpretation by users. This study investigates on the visual attributes performance of a sequence logo in helping users to perceive and interpret the information based on preattentive theories and Gestalt principl...

  19. Individual differences in visual perception and memory

    NARCIS (Netherlands)

    Colizoli, O.

    2014-01-01

    There is substantial variation in perception and memory in humans. There are individuals who cannot see red at all, and there are individuals who hear colors and taste words. What determines the differences and similarities between individuals' perception and memory? Can we characterize the neural

  20. simEye: computer-based simulation of visual perception under various eye defects using Zernike polynomials

    OpenAIRE

    Fink, Wolfgang; Micol, Daniel

    2006-01-01

    We describe a computer eye model that allows for aspheric surfaces and a three-dimensional computer-based ray-tracing technique to simulate optical properties of the human eye and visual perception under various eye defects. Eye surfaces, such as the cornea, eye lens, and retina, are modeled or approximated by a set of Zernike polynomials that are fitted to input data for the respective surfaces. A ray-tracing procedure propagates light rays using Snell’s law of refraction from an input objec...

  1. Mechanisms of Percept-Percept and Image-Percept Integration in Vision: Behavioral and Electrophysiological Evidence

    Science.gov (United States)

    Dalvit, Silvia; Eimer, Martin

    2011-01-01

    Previous research has shown that the detection of a visual target can be guided not only by the temporal integration of two percepts, but also by integrating a percept and an image held in working memory. Behavioral and event-related brain potential (ERP) measures were obtained in a target detection task that required temporal integration of 2…

  2. DIFFERENT LEVEL OF LEARNED-HELPLESSNESS AMONG HIGH SCHOOL STUDENTS WITH LOWER GRADE AND HIGHER GRADE IN SALATIGA INDONESIA

    Directory of Open Access Journals (Sweden)

    Berta Esti Ari Prasetya

    2013-06-01

    consisted of 190 of higher grade students and 127 of lower grade students. Mann-Whitney U was used to analyse the data, considering that the data were not normally distributed. This test result showed that there was a significant difference between high school students with higher grade and lower grade (the Mann-Whitney U coefficient of 10,644, with z value of -1795, p <0.05 (p = 0036, 1-tailed, with students of lower grade tend to be more prone to experience learned-helplessness. Additional results from their subjective perception on their achievement were also discussed and so were the implications of the study.

  3. Subclinical alexithymia modulates early audio-visual perceptive and attentional event-related potentials

    Directory of Open Access Journals (Sweden)

    Dyna eDelle-Vigne

    2014-03-01

    Full Text Available Introduction:Previous studies have highlighted the advantage of audio–visual oddball tasks (instead of unimodal ones in order to electrophysiologically index subclinical behavioral differences. Since alexithymia is highly prevalent in the general population, we investigated whether the use of various bimodal tasks could elicit emotional effects in low- versus high-alexithymic scorers. Methods:Fifty students (33 females were split into groups based on low and high scores on the Toronto Alexithymia Scale. During event-related potential recordings, they were exposed to three kinds of audio–visual oddball tasks: neutral (geometrical forms and bips, animal (dog and cock with their respective shouts, or emotional (faces and voices stimuli. In each condition, participants were asked to quickly detect deviant events occurring amongst a train of frequent matching stimuli (e.g., push a button when a sad face–voice pair appeared amongst a train of neutral face–voice pairs. P100, N100, and P300 components were analyzed: P100 refers to visual perceptive processing, N100 to auditory ones, and the P300 relates to response-related stages. Results:High-alexithymic scorers presented a particular pattern of results when processing the emotional stimulations, reflected in early ERP components by increased P100 and N100 amplitudes in the emotional oddball tasks (P100: pConclusions:Our findings suggest that high-alexithymic scorers require heightened early attentional resources when confronted with emotional stimuli.

  4. Visual texture perception via graph-based semi-supervised learning

    Science.gov (United States)

    Zhang, Qin; Dong, Junyu; Zhong, Guoqiang

    2018-04-01

    Perceptual features, for example direction, contrast and repetitiveness, are important visual factors for human to perceive a texture. However, it needs to perform psychophysical experiment to quantify these perceptual features' scale, which requires a large amount of human labor and time. This paper focuses on the task of obtaining perceptual features' scale of textures by small number of textures with perceptual scales through a rating psychophysical experiment (what we call labeled textures) and a mass of unlabeled textures. This is the scenario that the semi-supervised learning is naturally suitable for. This is meaningful for texture perception research, and really helpful for the perceptual texture database expansion. A graph-based semi-supervised learning method called random multi-graphs, RMG for short, is proposed to deal with this task. We evaluate different kinds of features including LBP, Gabor, and a kind of unsupervised deep features extracted by a PCA-based deep network. The experimental results show that our method can achieve satisfactory effects no matter what kind of texture features are used.

  5. Understanding Consumers' In-store Visual Perception

    DEFF Research Database (Denmark)

    Clement, Jesper; Kristensen, Tore; Grønhaug, Kjell

    2013-01-01

    It is widely accepted that the human brain has limited capacity for perceptual stimuli and consumers'' visual attention, when searching for a particular product or brand in a grocery store, should then be limited by the boundaries of their own perceptual capacity. In this exploratory study, we...... examine the relationship between abundant in-store stimuli and limited human perceptual capacity. Specifically, we test the influence of package design features on visual attention. Data was collected through two eye-tracking experiments, one in a grocery store using wireless eye-tracking equipment......, and another in a lab setting. Findings show that consumers have fragmented visual attention during grocery shopping, and that their visual attention is simultaneously influenced and disrupted by the shelf display. Physical design features such as shape and contrast dominate the initial phase of searching...

  6. The Computerized Perceptual Motor Skills Assessment: A new visual perceptual motor skills evaluation tool for children in early elementary grades.

    Science.gov (United States)

    Howe, Tsu-Hsin; Chen, Hao-Ling; Lee, Candy Chieh; Chen, Ying-Dar; Wang, Tien-Ni

    2017-10-01

    Visual perceptual motor skills have been proposed as underlying courses of handwriting difficulties. However, there is no evaluation tool currently available to assess these skills comprehensively and to serve as a sensitive measure. The purpose of this study was to validate the Computerized Perceptual Motor Skills Assessment (CPMSA), a newly developed evaluation tool for children in early elementary grades. Its test-retest reliability, concurrent validity, discriminant validity, and responsiveness were examined in 43 typically developing children and 26 children with handwriting difficulty. The CPMSA demonstrated excellent reliability across all subtests with intra-class correlation coefficients (ICCs)≥0.80. Significant moderate correlations between the domains of the CPMSA and corresponding gold standards including Beery VMI, the TVPS-3, and the eye-hand coordination subtest of the DTVP-2 demonstrated good concurrent validity. In addition, the CPMSA showed evidence of discriminant validity in samples of children with and without handwriting difficulty. This article provides evidence in support of the CPMSA. The CPMSA is a reliable, valid, and promising measure of visual perceptual motor skills for children in early elementary grades. Directions for future study and improvements to the assessment are discussed. Copyright © 2017. Published by Elsevier Ltd.

  7. [Objective assessment of disorders of visual perception following unilateral vestibular loss. Studies of the so-called Dandy symptom].

    Science.gov (United States)

    Stoll, W; Werner, F; Kauffmann, G

    1991-02-01

    Visual ability and compensatory eye movements during defined vertical oscillation were investigated in 20 patients with unilateral lesions of labyrinthine function and in 20 normal subjects. Oscillation frequencies were performed at the rate of 1 to 1.5 Hz with an amplitude of 5 cm, comparative to head locomotions of a running person. In synchronism with this, the visual function was tested with Landolt rings. Patients complaining of subjective visual disturbance during walking and running, also presented a measurable blur of vision under test conditions. In addition, eye movements were recorded and classified into three types. However, these eye movements showed no relation to gaze function. Our results suggest that the otolith-ocular reflex may participate in adjusting the vertical eye position during vertical stimulations at low frequencies. The effect of visual disturbances in patients with labyrinthine lesions is explained by the "efference-copy" initially described by von Holst. The efference-copy is responsible for the neutralisation of provoked retinal perceptions.

  8. Crime perception and Presidential evaluation in Mexico

    Directory of Open Access Journals (Sweden)

    Ricardo R. Gómez Vilchis

    2013-07-01

    Full Text Available How important are citizen perceptions of an increase in crime rate when they evaluate the President? This article uses Mexico as a case study to examine the relationship between perception of crime and citizen grading of the President. The research uses 11 national surveys from 1994 to 2006 to analyze the effects of perception of crime on citizen grading of the President before and after the 2000 presidential election. The main proposition is that, after the 2000 political transition, perception of crime, together with other economic variables, becomes more relevant and has stronger effects when citizens evaluate the President due to an increase of their expectations of the Executive's competence.

  9. Eye movements in depth to visual illusions

    NARCIS (Netherlands)

    Wismeijer, D.A.

    2009-01-01

    We perceive the three-dimensional (3D) environment that surrounds us with deceptive effortlessness. In fact, we are far from comprehending how the visual system provides us with this stable perception of the (3D) world around us. This thesis will focus on the interplay between visual perception of

  10. Percepção visual de grade senoidal radial após o consumo de álcool

    Directory of Open Access Journals (Sweden)

    Melyssa Kellyane Cavalcanti Galdino

    2011-01-01

    Full Text Available O objetivo deste trabalho foi comparar a percepção visual de contraste de adultos sem a ingestão de álcool e após a ingestão moderada de álcool - 0,09% Blood Alcohol Concentration (BAC, através da Função de Sensibilidade ao Contraste (FSC. Participaram dos experimentos cinco voluntárias, na faixa etária de 21 a 30 anos, com acuidade visual normal ou corrigida. Para medir a FSC, foram usados estímulos de grade senoidal radial de frequências de 0,25; 2 e 8 ciclos por grau de ângulo visual. Utilizou-se um delineamento experimental com medidas repetidas e o método psicofísico da escolha forçada. Os resultados demonstraram efeito significante de participantes (F4, 55 = 25,518; p < 0,001, de frequências (F2, 110 = 172,288; p < 0,001 e de interação entre frequências x condições x participantes (F8, 110 = 26,806; p < 0,001. Este estudo preliminar sugere alterações na FSC relacionadas à ingestão moderada de álcool.

  11. Study of the perception of visual motion in amblyopia using functional MRI

    International Nuclear Information System (INIS)

    Lu Guangming; Zhang Zhiqiang; Zhou Wenzhen; Zheng Ling; Yin Jie; Liang Ping

    2006-01-01

    Objective: To research the pathophysiological mechanism of anisometropic and strabismic amblyopia through observation of the cortex activation under the stimulus of visual motion using functional MRI (fMRI). Methods: Seven patients with anisometropic amblyopia and 10 patients with strabismic amblyopia were examined under the stimulus with the paradigm that task and control states were rotating and stationary grating with 1.5 T MR scanners. The data were processed using software of SPM offline, and the result was analyzed with single subject. An index of interocular difference of activation (IDA) was set for Mann-Whitney rank sum test to denote the extension of difference between activation of each eye. Results: There appeared activation on bilaterally occipital lobe in both group of amblyopia patients. There was mild activation on frontal lobe when amblyopic eyes were stimulated, but no activation when sound eyes. The MT area was regarded as region of interesting when analyzed, the activation of all sound eyes was stronger than amblyopic eyes in 7 anisometropic amblyopia patients. There were 5 patients whose level of activation of amblyopic eye's were lower than sound eye, and four were higher than sound eye, among the strabismic amblyopia patients except one patient's activation was none. There was statistical difference between IDA value of two groups (Z=2.382, P=0.017). Conclusion: There are more cortex areas activated of amblyopic eye than sound eye when single eye is stimulated. The function of visual motion maybe has been affected in anisometropic amblyopia. In strabismic amblyopia, the function of visual motion may relate to the underlying mechanism of strabismic, which suggests, as for the impairment of perception of visual motion, there is difference between two types of amblyopia. (authors)

  12. The Perception of Cooperativeness Without Any Visual or Auditory Communication.

    Science.gov (United States)

    Chang, Dong-Seon; Burger, Franziska; Bülthoff, Heinrich H; de la Rosa, Stephan

    2015-12-01

    Perceiving social information such as the cooperativeness of another person is an important part of human interaction. But can people perceive the cooperativeness of others even without any visual or auditory information? In a novel experimental setup, we connected two people with a rope and made them accomplish a point-collecting task together while they could not see or hear each other. We observed a consistently emerging turn-taking behavior in the interactions and installed a confederate in a subsequent experiment who either minimized or maximized this behavior. Participants experienced this only through the haptic force-feedback of the rope and made evaluations about the confederate after each interaction. We found that perception of cooperativeness was significantly affected only by the manipulation of this turn-taking behavior. Gender- and size-related judgments also significantly differed. Our results suggest that people can perceive social information such as the cooperativeness of other people even in situations where possibilities for communication are minimal.

  13. The Perception of Cooperativeness Without Any Visual or Auditory Communication

    Directory of Open Access Journals (Sweden)

    Dong-Seon Chang

    2015-12-01

    Full Text Available Perceiving social information such as the cooperativeness of another person is an important part of human interaction. But can people perceive the cooperativeness of others even without any visual or auditory information? In a novel experimental setup, we connected two people with a rope and made them accomplish a point-collecting task together while they could not see or hear each other. We observed a consistently emerging turn-taking behavior in the interactions and installed a confederate in a subsequent experiment who either minimized or maximized this behavior. Participants experienced this only through the haptic force-feedback of the rope and made evaluations about the confederate after each interaction. We found that perception of cooperativeness was significantly affected only by the manipulation of this turn-taking behavior. Gender- and size-related judgments also significantly differed. Our results suggest that people can perceive social information such as the cooperativeness of other people even in situations where possibilities for communication are minimal.

  14. Intraoperative perception and sensation in laser in situ keratomileusis (LASIK).

    Science.gov (United States)

    Srivannaboon, Sabong; Chansue, Ekktet

    2004-04-01

    To investigate intraoperative perception and sensation during Laser in situ Keratomileusis (LASIK). Sixty patients with uneventful LASIK were included. All procedures were performed by one surgeon with one technique. Any patient with intra-operative complications was excluded. The patients were asked to fill in the subjective evaluation form regarding their perception and sensation during the operation. Twenty-nine patients (48%) reported no pain and twenty-six patients (43%) reported no burning sensation during the surgery. Nineteen patients (32%) reported no light perception during the suction period of microkeratome. There was no correlation between duration of the suction and no light perception (R2 0.01). Thirty-four patients (56%) reported no trouble in maintaining visual fixation at the red light during the laser treatment. Ten patients (16%) reported they could clearly see the movement during the surgery and 5 out of 10 patients (50% of 16%) reported visual frightening. Fifty cases (84%) reported no visual frightening during the surgery after reassurance of the visual experience by the surgeon before the surgery. Patients undergoing LASIK may experience different visual perceptions. Reassurance of the intraoperative perception and sensation before the surgery can reduce the visual frightening.

  15. Modeling Color Difference for Visualization Design.

    Science.gov (United States)

    Szafir, Danielle Albers

    2018-01-01

    Color is frequently used to encode values in visualizations. For color encodings to be effective, the mapping between colors and values must preserve important differences in the data. However, most guidelines for effective color choice in visualization are based on either color perceptions measured using large, uniform fields in optimal viewing environments or on qualitative intuitions. These limitations may cause data misinterpretation in visualizations, which frequently use small, elongated marks. Our goal is to develop quantitative metrics to help people use color more effectively in visualizations. We present a series of crowdsourced studies measuring color difference perceptions for three common mark types: points, bars, and lines. Our results indicate that peoples' abilities to perceive color differences varies significantly across mark types. Probabilistic models constructed from the resulting data can provide objective guidance for designers, allowing them to anticipate viewer perceptions in order to inform effective encoding design.

  16. The Student Teachers Perceptions On Teaching Practice Supervision In Zimbabwe Is It A Process Of Grading Or Improvement Of Teaching Skills

    Directory of Open Access Journals (Sweden)

    Dr Sylod Chimhenga

    2017-07-01

    Full Text Available Supervisors are expected to observe how student teachers prepare deliver the lesson and conduct themselves as members of teaching profession and are expected to advise the students on how to improve their teaching skills. The present study is a descriptive survey which sought to analyze student teachers perception towards teaching practice as an exercise for grading or improvement and examine student teachers perception towards student-supervisor comments during discussion after classroom assessment. The sample comprised of 50 second year Diploma in Education who had undergone teaching practice in 2016. The students were purposefully sampled. In purposeful sampling the researcher selects the participants because they possess particular characteristics or knowledge being sought. A questionnaire was used to collect data for this study. The findings indicated that majority of student teachers who participated in the teaching practice perceived that the supervisors gave grades which did not reflect the comments made about the teaching performance of the student teacher. Based on the findings recommendations were made among others that assessment should match the comments on areas needing improvement and meaningful accompanying comments should be made to guide student teachers in the desired directions during teaching practice encourage student teachers to try harder or to give credit for work done well.

  17. Self-Perceptions, Discrepancies between Self- and Other-Perceptions, and Children's Self-Reported Emotions

    Science.gov (United States)

    Nuijens, Karen L.; Teglasi, Hedwig; Hancock, Gregory R.

    2009-01-01

    Self and others' perceptions of victimization, bullying, and academic competence were examined in relation to self-reported anxiety, depression, anger, and global self-worth in a non-clinical sample of second- and third-grade children. Previous studies document links between negative emotions and self-perceptions that are less favorable than…

  18. Public perceptions of west-side forests: improving visual impact assessments and designing thinnings and harvests for scenic integrity

    Science.gov (United States)

    Robert G. Ribe

    2013-01-01

    Perceptions of public forests’ acceptability can be infl uenced by aesthetic qualities, at both broad and project levels, aff ecting managers’ social license to act. Legal and methodological issues related to measuring and managing forest aesthetics in NEPA and NFMA decision-making are discussed. It is argued that conventional visual impact assessments—using...

  19. Brain functional network connectivity based on a visual task: visual information processing-related brain regions are significantly activated in the task state

    Directory of Open Access Journals (Sweden)

    Yan-li Yang

    2015-01-01

    Full Text Available It is not clear whether the method used in functional brain-network related research can be applied to explore the feature binding mechanism of visual perception. In this study, we investigated feature binding of color and shape in visual perception. Functional magnetic resonance imaging data were collected from 38 healthy volunteers at rest and while performing a visual perception task to construct brain networks active during resting and task states. Results showed that brain regions involved in visual information processing were obviously activated during the task. The components were partitioned using a greedy algorithm, indicating the visual network existed during the resting state. Z-values in the vision-related brain regions were calculated, confirming the dynamic balance of the brain network. Connectivity between brain regions was determined, and the result showed that occipital and lingual gyri were stable brain regions in the visual system network, the parietal lobe played a very important role in the binding process of color features and shape features, and the fusiform and inferior temporal gyri were crucial for processing color and shape information. Experimental findings indicate that understanding visual feature binding and cognitive processes will help establish computational models of vision, improve image recognition technology, and provide a new theoretical mechanism for feature binding in visual perception.

  20. Efficacy of a perceptual and visual-motor skill intervention program for students with dyslexia.

    Science.gov (United States)

    Fusco, Natália; Germano, Giseli Donadon; Capellini, Simone Aparecida

    2015-01-01

    To verify the efficacy of a perceptual and visual-motor skill intervention program for students with dyslexia. The participants were 20 students from third to fifth grade of a public elementary school in Marília, São Paulo, aged from 8 years to 11 years and 11 months, distributed into the following groups: Group I (GI; 10 students with developmental dyslexia) and Group II (GII; 10 students with good academic performance). A perceptual and visual-motor intervention program was applied, which comprised exercises for visual-motor coordination, visual discrimination, visual memory, visual-spatial relationship, shape constancy, sequential memory, visual figure-ground coordination, and visual closure. In pre- and post-testing situations, both groups were submitted to the Test of Visual-Perceptual Skills (TVPS-3), and the quality of handwriting was analyzed using the Dysgraphia Scale. The analyzed statistical results showed that both groups of students had dysgraphia in pretesting situation. In visual perceptual skills, GI presented a lower performance compared to GII, as well as in the quality of writing. After undergoing the intervention program, GI increased the average of correct answers in TVPS-3 and improved the quality of handwriting. The developed intervention program proved appropriate for being applied to students with dyslexia, and showed positive effects because it provided improved visual perception skills and quality of writing for students with developmental dyslexia.

  1. Occupational Therapy Interventions Effect on Visual-Motor Skills in Children with Learning Disorders

    Directory of Open Access Journals (Sweden)

    Batoul Mandani

    2007-07-01

    Full Text Available Objective: Visual-motor skill is a part of visual perception which can integrate visual processing skills to fine movements. Visual-motor dysfunction is often to cause problems in copying and writing. The purpose of this study is investigation of occupational therapy interventions effect on the visual-motor skill in children with learning disorders. Materials & Methods: In this interventional and experimental study, 23 students with learning disorders (2nd, 3rd, 4th grade were selected and they were divided (through Randomized Block Method into two groups, 11 persons as intervention group and the others as the control group (12 people. Both groups were administered the “Test of Visual-Motor Skills- Revised” (TVMS-R. Then case group received occupational therapy interventions for 16 sessions and two groups were administered by TVMS-R again. Data was analyzed by using paired T-test and independent T-test. Results: Total mark of TVMS-R demonstrated statistically significant difference in visual-motor skills between case and control groups (P<0/001. This test has 8 categories. Total mark of 1, 3,4,6,8 categories demonstrated that occupational therapy had significant effect on visual analysis skills (P<0/005. Total mark of 2, 5, 7 categories demonstrated that occupational therapy had significant effect on visual-spatial skills (P<0/001. Conclusion: Occupational therapy interventions had significant effect on the visual-motor skills and its items (visual-spatial, visual analysis, visual-motor integration and eye fixation skills.

  2. Place based teaching in the visual arts and art education

    DEFF Research Database (Denmark)

    Andersen, Kirsten Bak

    Contemporary Art and three orientations in visual culture pedagogy: Perception, Relational and Reflexive practice.......Contemporary Art and three orientations in visual culture pedagogy: Perception, Relational and Reflexive practice....

  3. Impairment in visual cognition in patients with Parkinson disease

    International Nuclear Information System (INIS)

    Hirayama, Kazumi; Ishioka, Toshiyuki

    2007-01-01

    Neural pathway for visual information processing involves retina, lateral geniculate body, primary visual cortex, and higher visual cortical areas, all of which have been reported to be disordered either functionally or pathologically in Parkinson disease (PD). As elementary visual disorders, there have been studies that reported reduced contrast sensitivity for middle to high spatial frequencies and impaired blue color perception. Most of those studies suggested retina as the damaged cite that is responsible for the impairments, whereas some studies pointed to the possible cortical involvement. Impairments of higher visual functions also have been reported. In the dorsal stream, impairments of object localization, depth perception, and mental rotation have been reported. In the ventral stream, object perception and visual integration of objects have been found to be impaired. A meta-analysis study, however, concluded that although there may be impairments in higher order functions like attention and problem solving capacity there is no firm evidence for the impairments of higher visual functions. Neuroimaging studies have found a relationship between reduced metabolism centered in the parietal lobe and impaired performance in higher visual functions. Impaired identification of overlapping figures has been reported in dementia with Lewy bodies a disease that is akin to PD. Capacity to discriminate textured areas has been found to be damaged in PD. We conducted a fluorodeoxyglucose-positron emission tomography (FDG-PET) study to explore the relationship between brain metabolism and perception of overlapping figures, perception of shapes defined by texture differences and perception of subjective contours in PD. It revealed that there is a correlation between reduced activation in lateral occipital complex and impaired performance for these tasks, suggesting some compromised ventral rout functions. (author)

  4. Construção e evidências psicométricas de uma escala de avaliação da percepção visual Construction and psychometric evidences of a visual perception scale

    Directory of Open Access Journals (Sweden)

    Suellen Marinho Andrade

    2012-01-01

    Full Text Available Este estudo teve como objetivo construir e conhecer os parâmetros psicométricos de um instrumento para análise da percepção visual de adultos. Para a construção da escala participaram 295 adultos saudáveis, sem déficits cognitivos ou perceptivo-visuais. Nesta etapa foi formulada uma escala tetrafatorial constituída por 20 itens que avaliam quatro dimensões referentes à percepção visual: constância da forma, figura-fundo, posição e relação espacial. Para obter evidências de validade foi utilizada uma amostra de 183 voluntários com boa saúde física e mental e acuidade visual normal ou corrigida. Os dados obtidos relatam a existência de concordância interjuízes, adequação semântica e significância no teste-reteste do instrumento. Os coeficientes de fidedignidade variaram de 0,84 a 0,93. Os quatro fatores esperados foram encontrados, cada um contendo 5 itens, e juntos explicaram 57,52% da variância do constructo. O instrumento apresentou parâmetros psicométricos adequados, o que pode justificar sua utilidade em pesquisas básicas e na prática clínica.The main objective of this study was to develop and examine the psychometric parameters of an instrument used to evaluate adults' visual perception. The basic assumption was that visual perception includes constancy of form, figure-ground, position and spatial relation. A 4-factor solution was expected. Respondents were 183 healthy adults without cognitive or visual perception impairment. In the instrument it was possible to establish the existence of inter-judges agreement, semantic adequacy and test-retest significance. The reliability coefficients ranged from 0.84 to 0.93. The four expected factors were found, each one containing 5 items. This solution accounted for 57.52% of the construct variance indicating that the instrument has good psychometric parameters, which suggests its applicability in scientific research and clinical practice.

  5. Early vision and visual attention

    OpenAIRE

    Gvozdenović Vasilije P.

    2003-01-01

    The question whether visual perception is spontaneous, sudden or is running through several phases, mediated by higher cognitive processes, was raised ever since the early work of Gestalt psychologists. In the early 1980s, Treisman proposed the feature integration theory of attention (FIT), based on the findings of neuroscience. Soon after publishing her theory a new scientific approach appeared investigating several visual perception phenomena. The most widely researched were the key constru...

  6. Multi-Level Visual Alphabets

    NARCIS (Netherlands)

    Israël, Menno; van der Schaar, Jetske; van den Broek, Egon; den Uyl, Marten J.; van der Putten, Peter; Djemal, K.; Deriche, M.

    2010-01-01

    A central debate in visual perception theory is the argument for indirect versus direct perception; i.e., the use of intermediate, abstract, and hierarchical representations versus direct semantic interpretation of images through interaction with the outside world. We present a content-based

  7. Studying Sensory Perception.

    Science.gov (United States)

    Ackerly, Spafford C.

    2001-01-01

    Explains the vestibular organ's role in balancing the body and stabilizing the visual world using the example of a hunter. Describes the relationship between sensory perception and learning. Recommends using optical illusions to illustrate the distinctions between external realities and internal perceptions. (Contains 13 references.) (YDS)

  8. The content of visual working memory alters processing of visual input prior to conscious access: Evidence from pupillometry

    NARCIS (Netherlands)

    Gayet, S.; Paffen, C.L.E.; Guggenmos, M.; Sterzer, P.; Stigchel, S. van der

    2017-01-01

    Visual working memory (VWM) allows for keeping relevant visual information available after termination of its sensory input. Storing information in VWM, however, affects concurrent conscious perception of visual input: initially suppressed visual input gains prioritized access to consciousness when

  9. Auditory Emotional Cues Enhance Visual Perception

    Science.gov (United States)

    Zeelenberg, Rene; Bocanegra, Bruno R.

    2010-01-01

    Recent studies show that emotional stimuli impair performance to subsequently presented neutral stimuli. Here we show a cross-modal perceptual enhancement caused by emotional cues. Auditory cue words were followed by a visually presented neutral target word. Two-alternative forced-choice identification of the visual target was improved by…

  10. Making Time for Nature: Visual Exposure to Natural Environments Lengthens Subjective Time Perception and Reduces Impulsivity.

    Directory of Open Access Journals (Sweden)

    Meredith S Berry

    Full Text Available Impulsivity in delay discounting is associated with maladaptive behaviors such as overeating and drug and alcohol abuse. Researchers have recently noted that delay discounting, even when measured by a brief laboratory task, may be the best predictor of human health related behaviors (e.g., exercise currently available. Identifying techniques to decrease impulsivity in delay discounting, therefore, could help improve decision-making on a global scale. Visual exposure to natural environments is one recent approach shown to decrease impulsive decision-making in a delay discounting task, although the mechanism driving this result is currently unknown. The present experiment was thus designed to evaluate not only whether visual exposure to natural (mountains, lakes relative to built (buildings, cities environments resulted in less impulsivity, but also whether this exposure influenced time perception. Participants were randomly assigned to either a natural environment condition or a built environment condition. Participants viewed photographs of either natural scenes or built scenes before and during a delay discounting task in which they made choices about receiving immediate or delayed hypothetical monetary outcomes. Participants also completed an interval bisection task in which natural or built stimuli were judged as relatively longer or shorter presentation durations. Following the delay discounting and interval bisection tasks, additional measures of time perception were administered, including how many minutes participants thought had passed during the session and a scale measurement of whether time "flew" or "dragged" during the session. Participants exposed to natural as opposed to built scenes were less impulsive and also reported longer subjective session times, although no differences across groups were revealed with the interval bisection task. These results are the first to suggest that decreased impulsivity from exposure to natural as

  11. Color blindness and contrast perception in cuttlefish (Sepia officinalis) determined by a visual sensorimotor assay.

    Science.gov (United States)

    Mäthger, Lydia M; Barbosa, Alexandra; Miner, Simon; Hanlon, Roger T

    2006-05-01

    We tested color perception based upon a robust behavioral response in which cuttlefish (Sepia officinalis) respond to visual stimuli (a black and white checkerboard) with a quantifiable, neurally controlled motor response (a body pattern). In the first experiment, we created 16 checkerboard substrates in which 16 grey shades (from white to black) were paired with one green shade (matched to the maximum absorption wavelength of S. officinalis' sole visual pigment, 492 nm), assuming that one of the grey shades would give a similar achromatic signal to the tested green. In the second experiment, we created a checkerboard using one blue and one yellow shade whose intensities were matched to the cuttlefish's visual system. In both assays it was tested whether cuttlefish would show disruptive coloration on these checkerboards, indicating their ability to distinguish checkers based solely on wavelength (i.e., color). Here, we show clearly that cuttlefish must be color blind, as they showed non-disruptive coloration on the checkerboards whose color intensities were matched to the Sepia visual system, suggesting that the substrates appeared to their eyes as uniform backgrounds. Furthermore, we show that cuttlefish are able to perceive objects in their background that differ in contrast by approximately 15%. This study adds support to previous reports that S. officinalis is color blind, yet the question of how cuttlefish achieve "color-blind camouflage" in chromatically rich environments still remains.

  12. Longitudinal Change in the Relationship between Fundamental Motor Skills and Perceived Competence: Kindergarten to Grade 2

    Directory of Open Access Journals (Sweden)

    Jeff R. Crane

    2017-08-01

    Full Text Available As children transition from early to middle childhood, the relationship between motor skill proficiency and perceptions of physical competence should strengthen as skills improve and inflated early childhood perceptions decrease. This study examined change in motor skills and perceptions of physical competence and the relationship between those variables from kindergarten to grade 2. Participants were 250 boys and girls (Mean age = 5 years 8 months in kindergarten. Motor skills were assessed using the Test of Gross Motor Development-2 and perceptions were assessed using a pictorial scale of perceived competence. Mixed-design analyses of variance revealed there was a significant increase in object-control skills and perceptions from kindergarten to grade 2, but no change in locomotor skills. In kindergarten, linear regression showed that locomotor skills and object-control skills explained 10% and 9% of the variance, respectively, in perceived competence for girls, and 7% and 11%, respectively, for boys. In grade 2, locomotor skills predicted 11% and object-control skills predicted 19% of the variance in perceptions of physical competence, but only among the boys. Furthermore, the relationship between motor skills and perceptions of physical competence strengthened for boys only from early to middle childhood. However, it seems that forces other than motor skill proficiency influenced girls’ perceptions of their abilities in grade 2.

  13. Visual, Algebraic and Mixed Strategies in Visually Presented Linear Programming Problems.

    Science.gov (United States)

    Shama, Gilli; Dreyfus, Tommy

    1994-01-01

    Identified and classified solution strategies of (n=49) 10th-grade students who were presented with linear programming problems in a predominantly visual setting in the form of a computerized game. Visual strategies were developed more frequently than either algebraic or mixed strategies. Appendix includes questionnaires. (Contains 11 references.)…

  14. Neural associations of the early retinotopic cortex with the lateral occipital complex during visual perception.

    Directory of Open Access Journals (Sweden)

    Delong Zhang

    Full Text Available Previous studies have demonstrated that the early retinotopic cortex (ERC, i.e., V1/V2/V3 is highly associated with the lateral occipital complex (LOC during visual perception. However, it remains largely unclear how to evaluate their associations in quantitative way. The present study tried to apply a multivariate pattern analysis (MVPA to quantify the neural activity in ERC and its association with that of the LOC when participants saw visual images. To this end, we assessed whether low-level visual features (Gabor features could predict the neural activity in the ERC and LOC according to a voxel-based encoding model (VBEM, and then quantified the association of the neural activity between these regions by using an analogical VBEM. We found that the Gabor features remarkably predicted the activity of the ERC (e.g., the predicted accuracy was 52.5% for a participant instead of that of the LOC (4.2%. Moreover, the MVPA approach can also be used to establish corresponding relationships between the activity patterns in the LOC and those in the ERC (64.2%. In particular, we found that the integration of the Gabor features and LOC visual information could dramatically improve the 'prediction' of ERC activity (88.3%. Overall, the present study provides new evidences for the possibility of quantifying the association of the neural activity between the regions of ERC and LOC. This approach will help to provide further insights into the neural substrates of the visual processing.

  15. Visual perception and medical imaging

    International Nuclear Information System (INIS)

    Jaffe, C.C.

    1985-01-01

    Medical imaging represents a particularly distinct discipline for image processing since it uniquely depends on the ''expert observer'' and yet models of the human visual system are totally inadequate at the complex level to allow satisfactory prediction of observer response to a given image modification. An illustration of the difficulties in assessing observer performance is shown by a series of optical illustrations which demonstrate that net cognitive behavior is not readily predictable. Although many of these phenomena are often considered as exceptional visual events, the setting of complex images makes it difficult to entirely exclude at least partial operation of these impairments during performance of the diagnostic medical imaging task

  16. Local visual perception bias in children with high-functioning autism spectrum disorders; do we have the whole picture?

    Science.gov (United States)

    Falkmer, Marita; Black, Melissa; Tang, Julia; Fitzgerald, Patrick; Girdler, Sonya; Leung, Denise; Ordqvist, Anna; Tan, Tele; Jahan, Ishrat; Falkmer, Torbjorn

    2016-01-01

    While local bias in visual processing in children with autism spectrum disorders (ASD) has been reported to result in difficulties in recognizing faces and facially expressed emotions, but superior ability in disembedding figures, associations between these abilities within a group of children with and without ASD have not been explored. Possible associations in performance on the Visual Perception Skills Figure-Ground test, a face recognition test and an emotion recognition test were investigated within 25 8-12-years-old children with high-functioning autism/Asperger syndrome, and in comparison to 33 typically developing children. Analyses indicated a weak positive correlation between accuracy in Figure-Ground recognition and emotion recognition. No other correlation estimates were significant. These findings challenge both the enhanced perceptual function hypothesis and the weak central coherence hypothesis, and accentuate the importance of further scrutinizing the existance and nature of local visual bias in ASD.

  17. Gaze Patterns in Auditory-Visual Perception of Emotion by Children with Hearing Aids and Hearing Children

    Directory of Open Access Journals (Sweden)

    Yifang Wang

    2017-12-01

    Full Text Available This study investigated eye-movement patterns during emotion perception for children with hearing aids and hearing children. Seventy-eight participants aged from 3 to 7 were asked to watch videos with a facial expression followed by an oral statement, and these two cues were either congruent or incongruent in emotional valence. Results showed that while hearing children paid more attention to the upper part of the face, children with hearing aids paid more attention to the lower part of the face after the oral statement was presented, especially for the neutral facial expression/neutral oral statement condition. These results suggest that children with hearing aids have an altered eye contact pattern with others and a difficulty in matching visual and voice cues in emotion perception. The negative cause and effect of these gaze patterns should be avoided in earlier rehabilitation for hearing-impaired children with assistive devices.

  18. From perceptive fields to Gestalt.

    Science.gov (United States)

    Spillmann, Lothar

    2006-01-01

    Studies on visual psychophysics and perception conducted in the Freiburg psychophysics laboratory during the last 35 years are reviewed. Many of these were inspired by single-cell neurophysiology in cat and monkey. The aim was to correlate perceptual phenomena and their effects to possible neuronal mechanisms from retina to visual cortex and beyond. Topics discussed include perceptive field organization, figure-ground segregation and grouping, fading and filling-in, and long-range color interaction. While some of these studies succeeded in linking perception to neuronal response patterns, others require further investigation. The task of probing the human brain with perceptual phenomena continues to be a challenge for the future.

  19. A Case Study: Middle School Boys' Perceptions of Singing and Participation in Choir

    Science.gov (United States)

    Sweet, Bridget

    2010-01-01

    The purpose of this intrinsic case study was to learn about the perceptions of singing and participation in choir of the author's eighth grade choir students. Specific areas of focus included insight on why the eighth grade boys sing and enjoy singing, perceptions of singing in a daily choir class, and perceptions of singing in an auditioned…

  20. Self-Efficacy Beliefs and the Relation between Career Planning and Perception of Barriers

    Science.gov (United States)

    Cardoso, Paulo; Moreira, Joao Manuel

    2009-01-01

    This study tested the hypothesis that self-efficacy in career roles moderates the relation between perception of career barriers and career planning, in a study with Portuguese students, 488 in Grade 9 and 517 in Grade 12. The results supported the hypothesis only among Grade 9 girls, showing that perception of career barriers leads to less career…

  1. Bayesian networks and information theory for audio-visual perception modeling.

    Science.gov (United States)

    Besson, Patricia; Richiardi, Jonas; Bourdin, Christophe; Bringoux, Lionel; Mestre, Daniel R; Vercher, Jean-Louis

    2010-09-01

    Thanks to their different senses, human observers acquire multiple information coming from their environment. Complex cross-modal interactions occur during this perceptual process. This article proposes a framework to analyze and model these interactions through a rigorous and systematic data-driven process. This requires considering the general relationships between the physical events or factors involved in the process, not only in quantitative terms, but also in term of the influence of one factor on another. We use tools from information theory and probabilistic reasoning to derive relationships between the random variables of interest, where the central notion is that of conditional independence. Using mutual information analysis to guide the model elicitation process, a probabilistic causal model encoded as a Bayesian network is obtained. We exemplify the method by using data collected in an audio-visual localization task for human subjects, and we show that it yields a well-motivated model with good predictive ability. The model elicitation process offers new prospects for the investigation of the cognitive mechanisms of multisensory perception.

  2. Visual Magnocellular Function in Perceptual Disorders

    Directory of Open Access Journals (Sweden)

    David P. Crewther

    2011-05-01

    Full Text Available Developmental disorders such as autism spectrum disorders (ASD, dyslexia, schizophrenia and dyscalculia have also been reported to show abnormal visual perception. Central to the four disorders are observations of altered global/local perception, motion sensation and grouping that are suggestive of a magnocellular abnormality(s. Such psychophysical observations do not easily yield neurophysiological mechanisms that can explain the altered perception/vision. Nonlinear visual evoked potentials have allowed the separation of magnocellular (M and parvocellular (P contributions to the VEP (Klistorner et al., 1997. Using these tools we compare the patterns of abnormality in groups with visual disorders. The second order kernel responses of the VEP in autistic tendency show interference between P and M nonlinearities at high contrast (Sutherland & Crewther, 2010 resulting in a delay of completion of firing. While afferent latencies of M and P cortical activation are not different in ASD, the delay in completion may allow a revision of the ideas surrounding the “magnocellular advantage” which relate to the alterations observed in global and local perception.

  3. 7th to 9th grade obese adolescents' perceptions about obesity in Tamaulipas, Mexico.

    Science.gov (United States)

    de la Luz Martínez-Aguilar, Ma; Flores-Peña, Yolanda; de las Mercedes Rizo-Baeza, Ma; Aguilar-Hernández, Rosa Ma; Vázquez-Galindo, Laura; Gutiérres-Sánchez, Gustavo

    2010-01-01

    The objective was to explore obese adolescents perceptions about obesity among students in the seventh to ninth grade of a public school in Tamaulipas, Mexico. This is a qualitative study. Participants were 24 adolescents with a body mass index equal to or greater than the 95th percentile. Semistructured interviews were conducted until data saturation was reached and the meaning was understood. The adolescents defined obesity according to standards of measurement. They identified the hereditary factor as the main obesity cause, tended to underestimate obesity and had low self-esteem. They reported problems to do physical exercise and get clothes in order to improve their image, and feel rejected by their peers in school. It was identified that these adolescents have psychological defense mechanisms against obesity and that some of them are making efforts to lose weight. Obesity entails social and psychological health implications for persons suffering from this problem. Interventions should be put in practice.

  4. Developmental changes in reading do not alter the development of visual processing skills: An application of explanatory item response models in grades K-2

    Directory of Open Access Journals (Sweden)

    Kristi L Santi

    2015-02-01

    Full Text Available Visual processing has been widely studied in regard to its impact on a students’ ability to read. A less researched area is the role of reading in the development of visual processing skills. A cohort-sequential, accelerated-longitudinal design was utilized with 932 kindergarten, first, and second grade students to examine the impact of reading acquisition on the processing of various types of visual discrimination and visual motor test items. Students were assessed four times per year on a variety of reading measures and reading precursors and two popular measures of visual processing over a three-year period. Explanatory item response models were used to examine the roles of person and item characteristics on changes in visual processing abilities and changes in item difficulties over time. Results showed different developmental patterns for five types of visual processing test items, but most importantly failed to show consistent effects of learning to read on changes in item difficulty. Thus, the present study failed to find support for the hypothesis that learning to read alters performance on measures of visual processing. Rather, visual processing and reading ability improved together over time with no evidence to suggest cross-domain influences from reading to visual processing. Results are discussed in the context of developmental theories of visual processing and brain-based research on the role of visual skills in learning to read.

  5. Accumulation and Decay of Visual Capture and the Ventriloquism Aftereffect Caused by Brief Audio-Visual Disparities

    Science.gov (United States)

    Bosen, Adam K.; Fleming, Justin T.; Allen, Paul D.; O’Neill, William E.; Paige, Gary D.

    2016-01-01

    Visual capture and the ventriloquism aftereffect resolve spatial disparities of incongruent auditory-visual (AV) objects by shifting auditory spatial perception to align with vision. Here, we demonstrated the distinct temporal characteristics of visual capture and the ventriloquism aftereffect in response to brief AV disparities. In a set of experiments, subjects localized either the auditory component of AV targets (A within AV) or a second sound presented at varying delays (1-20s) after AV exposure (A2 after AV). AV targets were trains of brief presentations (1 or 20), covering a ±30° azimuthal range, and with ±8° (R or L) disparity. We found that the magnitude of visual capture generally reached its peak within a single AV pair and did not dissipate with time, while the ventriloquism aftereffect accumulated with repetitions of AV pairs and dissipated with time. Additionally, the magnitude of the auditory shift induced by each phenomenon was uncorrelated across listeners and visual capture was unaffected by subsequent auditory targets, indicating that visual capture and the ventriloquism aftereffect are separate mechanisms with distinct effects on auditory spatial perception. Our results indicate that visual capture is a ‘sample-and-hold’ process that binds related objects and stores the combined percept in memory, whereas the ventriloquism aftereffect is a ‘leaky integrator’ process that accumulates with experience and decays with time to compensate for cross-modal disparities. PMID:27837258

  6. Visual Motor and Perceptual Task Performance in Astigmatic Students

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    Erin M. Harvey

    2017-01-01

    Full Text Available Purpose. To determine if spectacle corrected and uncorrected astigmats show reduced performance on visual motor and perceptual tasks. Methods. Third through 8th grade students were assigned to the low refractive error control group (astigmatism < 1.00 D, myopia < 0.75 D, hyperopia < 2.50 D, and anisometropia < 1.50 D or bilateral astigmatism group (right and left eye ≥ 1.00 D based on cycloplegic refraction. Students completed the Beery-Buktenica Developmental Test of Visual Motor Integration (VMI and Visual Perception (VMIp. Astigmats were randomly assigned to testing with/without correction and control group was tested uncorrected. Analyses compared VMI and VMIp scores for corrected and uncorrected astigmats to the control group. Results. The sample included 333 students (control group 170, astigmats tested with correction 75, and astigmats tested uncorrected 88. Mean VMI score in corrected astigmats did not differ from the control group (p=0.829. Uncorrected astigmats had lower VMI scores than the control group (p=0.038 and corrected astigmats (p=0.007. Mean VMIp scores for uncorrected (p=0.209 and corrected astigmats (p=0.124 did not differ from the control group. Uncorrected astigmats had lower mean scores than the corrected astigmats (p=0.003. Conclusions. Uncorrected astigmatism influences visual motor and perceptual task performance. Previously spectacle treated astigmats do not show developmental deficits on visual motor or perceptual tasks when tested with correction.

  7. Perception of illusory contour figures: Microgenetic analysis

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    Gvozdenović Vasilije P.

    2004-01-01

    Full Text Available Microgenetic analysis was used to investigate perception of illusory contour figures which represent whole, completed forms on the basis of segmented, incomplete stimulation. The analysis provided an experimental approach to this phenomenon which was standardly investigated phenomenologically. Experimental procedure consisted of two phases: a priming phase and b test phase which consisted of visual search task. Two types of visual search tasks were applied: (i classic detection, in which subjects were detecting presence or absence of the target stimuli and (ii two-alternative forced choice, 2AFC, in which subjects performed discrimination between two concurrent targets (target A vs. target B. Variation of exposition of prim stimuli was used as an indication of the percept formation period. Concepts like early vision, visual attention and feature binding were investigated. Four experiments were conducted. Their outcome showed that (i perception of amodal figure requires visual attention, (ii features binding precedes spatial attention and (iii time period of percept formation is dependent of task properties and varies between 50 - 150 ms. Some results obtained in this research could be explained by feature-integration theory (Treisman & Gelade, 1980; Treisman, 1986. Furthermore, percept formation period data comply with data acquired in Elliott & Müller's psychophysical research (1998.

  8. Visual Thinking in Teaching History: Reading the Visual Thinking Skills of 12 Year-Old Pupils in Istanbul

    Science.gov (United States)

    Dilek, Gulcin

    2010-01-01

    This study aims to explore the visual thinking skills of some sixth grade (12-13 year-old) primary pupils who created visual interpretations during history courses. Pupils drew pictures describing historical scenes or events based on visual sources. They constructed these illustrations by using visual and written primary and secondary sources in…

  9. Reconfigurable Auditory-Visual Display

    Science.gov (United States)

    Begault, Durand R. (Inventor); Anderson, Mark R. (Inventor); McClain, Bryan (Inventor); Miller, Joel D. (Inventor)

    2008-01-01

    System and method for visual and audible communication between a central operator and N mobile communicators (N greater than or equal to 2), including an operator transceiver and interface, configured to receive and display, for the operator, visually perceptible and audibly perceptible signals from each of the mobile communicators. The interface (1) presents an audible signal from each communicator as if the audible signal is received from a different location relative to the operator and (2) allows the operator to select, to assign priority to, and to display, the visual signals and the audible signals received from a specified communicator. Each communicator has an associated signal transmitter that is configured to transmit at least one of the visual signals and the audio signal associated with the communicator, where at least one of the signal transmitters includes at least one sensor that senses and transmits a sensor value representing a selected environmental or physiological parameter associated with the communicator.

  10. Os efeitos da idade na percepção visual de grades senoidais em luminância baixa The effects of age on visual perception of sine-wave gratings at low luminance

    Directory of Open Access Journals (Sweden)

    Natanael Antonio dos Santos

    2006-01-01

    Full Text Available O objetivo deste trabalho foi investigar a função de sensibilidade ao contraste (FSC de adultos e idosos (20-23, 30-39, 40-49, 50-59, 60-69 anos para grades senoidais de 0,25 a 2 cpg em luminância baixa. Todos os participantes apresentavam acuidade visual normal e se encontravam livres de doenças oculares identificáveis. Foram estimados limiares de contraste para 30 participantes (seis em cada faixa etária utilizando o método psicofísico da escolha forçada. Neste método, os participantes tinham que escolher um estímulo contendo uma freqüência de teste (grade senoidal em baixo contraste ou um estímulo neutro com luminância média de 0,7 cd/m². Os resultados mostraram que os grupos de 50-59 e 60-69 anos apresentaram prejuízos significativos na FSC nas freqüências espaciais de 1 e 2 cpg comparados ao grupo de 20-23 anos. Estes resultados sugerem alterações relacionadas à idade na FSC de freqüências espaciais em níveis baixos de luminância.The aim of this work was to investigate the contrast sensitivity function for sine-wave gratings in the range between 0.25-2 cpd in young and older adults (20-23, 30-39, 40-49, 50-59, 60-69 years old using low luminance. All subjects were free from identifiable ocular disease and had normal acuity. We measured the contrast thresholds for 30 participants (six volunteers in each age using the psychophysical forced-choice staircase method. In this method the volunteers had to choose the stimulus containing a test frequency at low contrast (e.g., a sine-wave grating, or another neutral stimulus at mean luminance (0.7 cd/m². The results showed significant changes of CSF for sine-wave gratings at 1 and 2 cpd for the adults 50-59 and 60-69 years old compared to the adults of 20-23 years old. These results suggest age-related changes in the CSF for sine-wave grating at low luminance levels.

  11. VISUAL PERCEPTION BASED AUTOMATIC RECOGNITION OF CELL MOSAICS IN HUMAN CORNEAL ENDOTHELIUMMICROSCOPY IMAGES

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    Yann Gavet

    2011-05-01

    Full Text Available The human corneal endothelium can be observed with two types of microscopes: classical optical microscope for ex-vivo imaging, and specular optical microscope for in-vivo imaging. The quality of the cornea is correlated to the endothelial cell density and morphometry. Automatic methods to analyze the human corneal endothelium images are still not totally efficient. Image analysis methods that focus only on cell contours do not give good results in presence of noise and of bad conditions of acquisition. More elaborated methods introduce regional informations in order to performthe cell contours completion, thus implementing the duality contour-region. Their good performance can be explained by their connections with several basic principles of human visual perception (Gestalt Theory and Marr's computational theory.

  12. Visual Aversive Learning Compromises Sensory Discrimination.

    Science.gov (United States)

    Shalev, Lee; Paz, Rony; Avidan, Galia

    2018-03-14

    Aversive learning is thought to modulate perceptual thresholds, which can lead to overgeneralization. However, it remains undetermined whether this modulation is domain specific or a general effect. Moreover, despite the unique role of the visual modality in human perception, it is unclear whether this aspect of aversive learning exists in this modality. The current study was designed to examine the effect of visual aversive outcomes on the perception of basic visual and auditory features. We tested the ability of healthy participants, both males and females, to discriminate between neutral stimuli, before and after visual learning. In each experiment, neutral stimuli were associated with aversive images in an experimental group and with neutral images in a control group. Participants demonstrated a deterioration in discrimination (higher discrimination thresholds) only after aversive learning. This deterioration was measured for both auditory (tone frequency) and visual (orientation and contrast) features. The effect was replicated in five different experiments and lasted for at least 24 h. fMRI neural responses and pupil size were also measured during learning. We showed an increase in neural activations in the anterior cingulate cortex, insula, and amygdala during aversive compared with neutral learning. Interestingly, the early visual cortex showed increased brain activity during aversive compared with neutral context trials, with identical visual information. Our findings imply the existence of a central multimodal mechanism, which modulates early perceptual properties, following exposure to negative situations. Such a mechanism could contribute to abnormal responses that underlie anxiety states, even in new and safe environments. SIGNIFICANCE STATEMENT Using a visual aversive-learning paradigm, we found deteriorated discrimination abilities for visual and auditory stimuli that were associated with visual aversive stimuli. We showed increased neural

  13. Visual Working Memory and Perception Speed of 3- to 6-Year-Old Children Tested with a Matrix Film Battery Test

    Science.gov (United States)

    Pittorf, Martin L.; Lehmann, Wolfgang; Huckauf, Anke

    2014-01-01

    In this study the visual working memory (VWM) and perception speed of 60 children between the ages of three and six years were tested with an age-based, easy-to-handle Matrix Film Battery Test (reliability R?=?0.71). It was thereby affirmed that the VWM is age dependent (correlation coefficient r?=?0.66***) as expected. Furthermore, a significant…

  14. Cortical visual impairment: Characteristics and treatment

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    Vučinić Vesna

    2014-01-01

    Full Text Available According to the latest studies, Cortical visual impairment – CVI is one of the most common causes of problems and difficulties in visual functioning. It results from the impairment of the central part of visual system, i.e. visual cortex, posterior visual pathway, or both. The diagnosis is usually made in the first three years of life. The aim of this paper is to present the characteristics of children with CVI, and the strategies used for treatment. CVI has a negative impact on almost all developmental domains, visual-perceptive skills, motor skills, cognitive skills, and social skills. In children with CVI, vision ranges from the total inability to see to minimal visual perceptive difficulties, while more than 50% have multiple disabilities. Due to the progress in understanding the patterns of neuron activity and neuroplasticity, as well as the intensive studies of strengths and weaknesses of children with CVI, special treatment has been designed and performed in the last few decades, which provides optimal visual functioning in everyday life for these children.

  15. A link between visual disambiguation and visual memory.

    Science.gov (United States)

    Hegdé, Jay; Kersten, Daniel

    2010-11-10

    Sensory information in the retinal image is typically too ambiguous to support visual object recognition by itself. Theories of visual disambiguation posit that to disambiguate, and thus interpret, the incoming images, the visual system must integrate the sensory information with previous knowledge of the visual world. However, the underlying neural mechanisms remain unclear. Using functional magnetic resonance imaging (fMRI) of human subjects, we have found evidence for functional specialization for storing disambiguating information in memory versus interpreting incoming ambiguous images. Subjects viewed two-tone, "Mooney" images, which are typically ambiguous when seen for the first time but are quickly disambiguated after viewing the corresponding unambiguous color images. Activity in one set of regions, including a region in the medial parietal cortex previously reported to play a key role in Mooney image disambiguation, closely reflected memory for previously seen color images but not the subsequent disambiguation of Mooney images. A second set of regions, including the superior temporal sulcus, showed the opposite pattern, in that their responses closely reflected the subjects' percepts of the disambiguated Mooney images on a stimulus-to-stimulus basis but not the memory of the corresponding color images. Functional connectivity between the two sets of regions was stronger during those trials in which the disambiguated percept was stronger. This functional interaction between brain regions that specialize in storing disambiguating information in memory versus interpreting incoming ambiguous images may represent a general mechanism by which previous knowledge disambiguates visual sensory information.

  16. Audio-visual speech perception in infants and toddlers with Down syndrome, fragile X syndrome, and Williams syndrome.

    Science.gov (United States)

    D'Souza, Dean; D'Souza, Hana; Johnson, Mark H; Karmiloff-Smith, Annette

    2016-08-01

    Typically-developing (TD) infants can construct unified cross-modal percepts, such as a speaking face, by integrating auditory-visual (AV) information. This skill is a key building block upon which higher-level skills, such as word learning, are built. Because word learning is seriously delayed in most children with neurodevelopmental disorders, we assessed the hypothesis that this delay partly results from a deficit in integrating AV speech cues. AV speech integration has rarely been investigated in neurodevelopmental disorders, and never previously in infants. We probed for the McGurk effect, which occurs when the auditory component of one sound (/ba/) is paired with the visual component of another sound (/ga/), leading to the perception of an illusory third sound (/da/ or /tha/). We measured AV integration in 95 infants/toddlers with Down, fragile X, or Williams syndrome, whom we matched on Chronological and Mental Age to 25 TD infants. We also assessed a more basic AV perceptual ability: sensitivity to matching vs. mismatching AV speech stimuli. Infants with Williams syndrome failed to demonstrate a McGurk effect, indicating poor AV speech integration. Moreover, while the TD children discriminated between matching and mismatching AV stimuli, none of the other groups did, hinting at a basic deficit or delay in AV speech processing, which is likely to constrain subsequent language development. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Reading your own lips: common-coding theory and visual speech perception.

    Science.gov (United States)

    Tye-Murray, Nancy; Spehar, Brent P; Myerson, Joel; Hale, Sandra; Sommers, Mitchell S

    2013-02-01

    Common-coding theory posits that (1) perceiving an action activates the same representations of motor plans that are activated by actually performing that action, and (2) because of individual differences in the ways that actions are performed, observing recordings of one's own previous behavior activates motor plans to an even greater degree than does observing someone else's behavior. We hypothesized that if observing oneself activates motor plans to a greater degree than does observing others, and if these activated plans contribute to perception, then people should be able to lipread silent video clips of their own previous utterances more accurately than they can lipread video clips of other talkers. As predicted, two groups of participants were able to lipread video clips of themselves, recorded more than two weeks earlier, significantly more accurately than video clips of others. These results suggest that visual input activates speech motor activity that links to word representations in the mental lexicon.

  18. Perception of visual texture and the expression of disruptive camouflage by the cuttlefish, Sepia officinalis

    Science.gov (United States)

    Kelman, E.J; Baddeley, R.J; Shohet, A.J; Osorio, D

    2007-01-01

    Juvenile cuttlefish (Sepia officinalis) camouflage themselves by changing their body pattern according to the background. This behaviour can be used to investigate visual perception in these molluscs and may also give insight into camouflage design. Edge detection is an important aspect of vision, and here we compare the body patterns that cuttlefish produced in response to checkerboard backgrounds with responses to backgrounds that have the same spatial frequency power spectrum as the checkerboards, but randomized spatial phase. For humans, phase randomization removes visual edges. To describe the cuttlefish body patterns, we scored the level of expression of 20 separate pattern ‘components’, and then derived principal components (PCs) from these scores. After varimax rotation, the first component (PC1) corresponded closely to the so-called disruptive body pattern, and the second (PC2) to the mottle pattern. PC1 was predominantly expressed on checkerboards, and PC2 on phase-randomized backgrounds. Thus, cuttlefish probably have edge detectors that control the expression of disruptive pattern. Although the experiments used unnatural backgrounds, it seems probable that cuttlefish display disruptive camouflage when there are edges in the visual background caused by discrete objects such as pebbles. We discuss the implications of these findings for our understanding of disruptive camouflage. PMID:17389219

  19. Speech Perception as a Multimodal Phenomenon

    OpenAIRE

    Rosenblum, Lawrence D.

    2008-01-01

    Speech perception is inherently multimodal. Visual speech (lip-reading) information is used by all perceivers and readily integrates with auditory speech. Imaging research suggests that the brain treats auditory and visual speech similarly. These findings have led some researchers to consider that speech perception works by extracting amodal information that takes the same form across modalities. From this perspective, speech integration is a property of the input information itself. Amodal s...

  20. Implications on visual apperception: energy, duration, structure and synchronization.

    Science.gov (United States)

    Bókkon, I; Vimal, Ram Lakhan Pandey

    2010-07-01

    Although primary visual cortex (V1 or striate) activity per se is not sufficient for visual apperception (normal conscious visual experiences and conscious functions such as detection, discrimination, and recognition), the same is also true for extrastriate visual areas (such as V2, V3, V4/V8/VO, V5/M5/MST, IT, and GF). In the lack of V1 area, visual signals can still reach several extrastriate parts but appear incapable of generating normal conscious visual experiences. It is scarcely emphasized in the scientific literature that conscious perceptions and representations must have also essential energetic conditions. These energetic conditions are achieved by spatiotemporal networks of dynamic mitochondrial distributions inside neurons. However, the highest density of neurons in neocortex (number of neurons per degree of visual angle) devoted to representing the visual field is found in retinotopic V1. It means that the highest mitochondrial (energetic) activity can be achieved in mitochondrial cytochrome oxidase-rich V1 areas. Thus, V1 bear the highest energy allocation for visual representation. In addition, the conscious perceptions also demand structural conditions, presence of adequate duration of information representation, and synchronized neural processes and/or 'interactive hierarchical structuralism.' For visual apperception, various visual areas are involved depending on context such as stimulus characteristics such as color, form/shape, motion, and other features. Here, we focus primarily on V1 where specific mitochondrial-rich retinotopic structures are found; we will concisely discuss V2 where smaller riches of these structures are found. We also point out that residual brain states are not fully reflected in active neural patterns after visual perception. Namely, after visual perception, subliminal residual states are not being reflected in passive neural recording techniques, but require active stimulation to be revealed.

  1. The reliability and clinical correlates of figure-ground perception in schizophrenia.

    Science.gov (United States)

    Malaspina, Dolores; Simon, Naomi; Goetz, Raymond R; Corcoran, Cheryl; Coleman, Eliza; Printz, David; Mujica-Parodi, Lilianne; Wolitzky, Rachel

    2004-01-01

    Schizophrenia subjects are impaired in a number of visual attention paradigms. However, their performance on tests of figure-ground visual perception (FGP), which requires subjects to visually discriminate figures embedded in a rival background, is relatively unstudied. We examined FGP in 63 schizophrenia patients and 27 control subjects and found that the patients performed the FGP test reliably and had significantly lower FGP scores than the control subjects. Figure-ground visual perception was significantly correlated with other neuropsychological test scores and was inversely related to negative symptoms. It was unrelated to antipsychotic medication treatment. Figure-ground visual perception depends on "top down" processing of visual stimuli, and thus this data suggests that dysfunction in the higher-level pathways that modulate visual perceptual processes may also be related to a core defect in schizophrenia.

  2. Conscious visual memory with minimal attention

    NARCIS (Netherlands)

    Pinto, Y.; Vandenbroucke, A.R.; Otten, M.; Sligte, I.G.; Seth, A.K.; Lamme, V.A.F.

    2017-01-01

    Is conscious visual perception limited to the locations that a person attends? The remarkable phenomenon of change blindness, which shows that people miss nearly all unattended changes in a visual scene, suggests the answer is yes. However, change blindness is found after visual interference (a mask

  3. Factors contributing to speech perception scores in long-term pediatric cochlear implant users.

    Science.gov (United States)

    Davidson, Lisa S; Geers, Ann E; Blamey, Peter J; Tobey, Emily A; Brenner, Christine A

    2011-02-01

    The objectives of this report are to (1) describe the speech perception abilities of long-term pediatric cochlear implant (CI) recipients by comparing scores obtained at elementary school (CI-E, 8 to 9 yrs) with scores obtained at high school (CI-HS, 15 to 18 yrs); (2) evaluate speech perception abilities in demanding listening conditions (i.e., noise and lower intensity levels) at adolescence; and (3) examine the relation of speech perception scores to speech and language development over this longitudinal timeframe. All 112 teenagers were part of a previous nationwide study of 8- and 9-yr-olds (N = 181) who received a CI between 2 and 5 yrs of age. The test battery included (1) the Lexical Neighborhood Test (LNT; hard and easy word lists); (2) the Bamford Kowal Bench sentence test; (3) the Children's Auditory-Visual Enhancement Test; (4) the Test of Auditory Comprehension of Language at CI-E; (5) the Peabody Picture Vocabulary Test at CI-HS; and (6) the McGarr sentences (consonants correct) at CI-E and CI-HS. CI-HS speech perception was measured in both optimal and demanding listening conditions (i.e., background noise and low-intensity level). Speech perception scores were compared based on age at test, lexical difficulty of stimuli, listening environment (optimal and demanding), input mode (visual and auditory-visual), and language age. All group mean scores significantly increased with age across the two test sessions. Scores of adolescents significantly decreased in demanding listening conditions. The effect of lexical difficulty on the LNT scores, as evidenced by the difference in performance between easy versus hard lists, increased with age and decreased for adolescents in challenging listening conditions. Calculated curves for percent correct speech perception scores (LNT and Bamford Kowal Bench) and consonants correct on the McGarr sentences plotted against age-equivalent language scores on the Test of Auditory Comprehension of Language and Peabody

  4. Visual perception and appraisal of persons with impairments: a randomised controlled field experiment using photo elicitation.

    Science.gov (United States)

    Reinhardt, Jan Dietrich; Ballert, Carolina Saskia; Fellinghauer, Bernd; Lötscher, Alexander; Gradinger, Felix; Hilfiker, Roger; Graf, Sibylle; Stucki, Gerold

    2011-01-01

    Visual cues from persons with impairments may trigger stereotypical generalisations that lead to prejudice and discrimination. The main objective of this pilot study is to examine whether visual stimuli of impairment activate latent prejudice against disability and whether this connection can be counteracted with priming strategies. In a field experiment, participants were asked to rate photographs showing models with mental impairments, wheelchair users with paraplegia, and persons without any visible impairment. Participants should appraise the models with regard to several features (e.g. communicativeness, intelligence). One hundred participants rated 12 photo models yielding a total of 1183 observations. One group of participants was primed with a cover story introducing visual perception of impairment as the study's gist, while controls received neutral information. Photo models with mental impairments were rated lowest and models without visible impairment highest. In participants who did not have prior contacts with persons with impairments, priming led to a levelling of scores of models with and without impairment. Prior contacts with persons with impairments created similar effects as the priming. Unexpectedly, a pattern of converse double discrimination to the disadvantage of men with mental impairments was revealed. Signs of stereotypical processing of visual cues of impairment have been found in participants of the Swiss general population. Personal contact with persons with impairments as well as priming participants seems to reduce stereotyping.

  5. A brief measure of adolescent perceptions of school climate.

    Science.gov (United States)

    White, Nick; La Salle, Tamika; Ashby, Jeffrey S; Meyers, Joel

    2014-09-01

    Student perceptions of school climate represent the ways students feel about the school environment. These include perceptions regarding safety, teaching and learning, and relationships within the school. It has been found that student perceptions of school climate are positively correlated with academic achievement (Brookover et al., 1978), and negatively correlated with risky behaviors (Bandyopadhyay, Cornell, & Konold, 2009; Bayar & Ucanok, 2012; Wang, Berry, & Swearer, 2013). The Georgia Brief School Climate Inventory (GaBSCI) is a measure of student perceptions of school climate. The brevity of the 9-item instrument makes it ideal as a general measure that can be used to monitor student perceptions of school climate. The survey was anonymously administered to 130,968 sixth- and eighth-grade students in the state of Georgia. Cronbach's alpha for the scale was 0.71. Exploratory and confirmatory factor analyses verified the scale's structure. Student perceptions of climate from the GaBSCI varied based on race/ethnicity, gender, and grade. Additional support for the construct validity of the GaBSCI was obtained based on its relationships with several behaviors related to bullying, and the moderating effects of grade and gender on these relationships. Implications for research and practice are discussed. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  6. Grade Inflation: Faculty Lived-Experiences and Perceptions

    Science.gov (United States)

    Schroeder, Nan

    2016-01-01

    The research area of this study is the phenomenon of grade inflation in higher educational organizations. Using a qualitative phenomenological research design, seven faculty members from a higher educational organization were purposefully selected to participate in a semi-structured, face-to-face interview. The participants were of various ages,…

  7. A brain electrophysiological correlate of depth perception

    International Nuclear Information System (INIS)

    Akay, Ahmet; Celebi, Gurbuz

    2009-01-01

    To investigate brain electrical activity accompanying depth perception using random-dot stereograms. Additional experiments were conducted to ascertain the specificity of this potential to depth perception. In the present study, we performed 3 different and independent experiments on 34 subjects to establish the relationship between depth perception and its cortical electrophysiological correlate. Visual evoked potentials in response to visual stimulation by random-dot stereograms were recorded. To achieve this goal, a data acquisition and analysis system, different from common visual evoked potential recording systems, consisting of 2 personal computers, was used. One of the computers was used to generate the visual stimulus patterns and the other to record and digitally average the potentials evoked by the stimuli. This study was carried out at the Department of Biophysics of Ege University Medical School, Izmir, Turkey, from April to December, 2006. A negative potential component, which is thought to arise in association with depth perception, was recorded from the occipital region from 30 of the 34 subjects. Typically, it had a mean latency of 211.46 ms and 6.40 micron V amplitude. The negative potential is related to depth perception, as this component is present in the responses to stimulus, which carries disparity information but is absent when the stimulus is switched to no disparity information. Additional experiments also showed that the specificity of this component to depth perception becomes evident beyond doubt. (author)

  8. Impact of focal spot size on radiologic image quality: A visual grading analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gorham, Sinead [Diagnostic Imaging, Biological Imaging Research, UCD School of Medicine and Medical Science, Health Science, Belfield, UCD, Dublin 4 (Ireland); Brennan, Patrick C., E-mail: patrick.brennan@ucd.i [Diagnostic Imaging, Biological Imaging Research, UCD School of Medicine and Medical Science, Health Science, Belfield, UCD, Dublin 4 (Ireland)

    2010-11-15

    Fine and broad focal spot sizes are available on general X-ray tubes. Excessive use of fine focus can impact on tube life and whilst it is established that fine focal spot size reduces geometric unsharpness, the extent of this benefit on clinical image quality is unclear. The current cadaver-based work compares images produced with effective focal sizes of 0.8 mm and 1.8 mm. Four projection types were included, lateral ankle, antero-posterior (AP) knee, AP thoracic spine and horizontal beam lateral (HBL) lumbar spine, and a visual grading analysis was used to assess visibility of anatomical criteria. Five clinicians scored each image using a 1-4 scoring scale, a reference image was employed for standardization and a Mann-Whitney U statistical test compared results derived from each focus. Radiation doses were monitored using a dose area product (DAP) meter. Statistical analyses demonstrated no significant differences between images produced at each focus, although a relationship between body part thickness and number of criteria with a higher (non-significant) score for the fine focus compared with the broad focal spot size was demonstrated. Choice of focus had no radiation dose implications. Fine foci X-ray sources are used predominantly for extremity imaging to enhance visualization of fine detail such as trabecular patterns, yet there is no evidence to support this practice. The argument for regular employment of fine foci, particularly for the type of acquisition and display devices used in this study, needs to be revisited.

  9. The Impact of Visual Impairment on Perceived School Climate

    Science.gov (United States)

    Schade, Benjamin; Larwin, Karen H.

    2015-01-01

    The current investigation examines whether visual impairment has an impact on a student's perception of the school climate. Using a large national sample of high school students, perceptions were examined for students with vision impairment relative to students with no visual impairments. Three factors were examined: self-reported level of…

  10. Elevated arousal levels enhance contrast perception.

    Science.gov (United States)

    Kim, Dongho; Lokey, Savannah; Ling, Sam

    2017-02-01

    Our state of arousal fluctuates from moment to moment-fluctuations that can have profound impacts on behavior. Arousal has been proposed to play a powerful, widespread role in the brain, influencing processes as far ranging as perception, memory, learning, and decision making. Although arousal clearly plays a critical role in modulating behavior, the mechanisms underlying this modulation remain poorly understood. To address this knowledge gap, we examined the modulatory role of arousal on one of the cornerstones of visual perception: contrast perception. Using a reward-driven paradigm to manipulate arousal state, we discovered that elevated arousal state substantially enhances visual sensitivity, incurring a multiplicative modulation of contrast response. Contrast defines vision, determining whether objects appear visible or invisible to us, and these results indicate that one of the consequences of decreased arousal state is an impaired ability to visually process our environment.

  11. Machine grading of lumber : practical concerns for lumber producers

    Science.gov (United States)

    William L. Galligan; Kent A. McDonald

    2000-01-01

    Machine lumber grading has been applied in commercial operations in North America since 1963, and research has shown that machine grading can improve the efficient use of wood. However, industry has been reluctant to apply research findings without clear evidence that the change from visual to machine grading will be a profitable one. For instance, mill managers need...

  12. Interactions of visual attention and quality perception

    NARCIS (Netherlands)

    Redi, J.A.; Liu, H.; Zunino, R.; Heynderickx, I.E.J.R.

    2011-01-01

    Several attempts to integrate visual saliency information in quality metrics are described in literature, albeit with contradictory results. The way saliency is integrated in quality metrics should reflect the mechanisms underlying the interaction between image quality assessment and visual

  13. Global-local visual biases correspond with visual-spatial orientation.

    Science.gov (United States)

    Basso, Michael R; Lowery, Natasha

    2004-02-01

    Within the past decade, numerous investigations have demonstrated reliable associations of global-local visual processing biases with right and left hemisphere function, respectively (cf. Van Kleeck, 1989). Yet the relevance of these biases to other cognitive functions is not well understood. Towards this end, the present research examined the relationship between global-local visual biases and perception of visual-spatial orientation. Twenty-six women and 23 men completed a global-local judgment task (Kimchi and Palmer, 1982) and the Judgment of Line Orientation Test (JLO; Benton, Sivan, Hamsher, Varney, and Spreen, 1994), a measure of visual-spatial orientation. As expected, men had better performance on JLO. Extending previous findings, global biases were related to better visual-spatial acuity on JLO. The findings suggest that global-local biases and visual-spatial orientation may share underlying cerebral mechanisms. Implications of these findings for other visually mediated cognitive outcomes are discussed.

  14. Visual-perceptual impairment in children with cerebral palsy: a systematic review.

    Science.gov (United States)

    Ego, Anne; Lidzba, Karen; Brovedani, Paola; Belmonti, Vittorio; Gonzalez-Monge, Sibylle; Boudia, Baya; Ritz, Annie; Cans, Christine

    2015-04-01

    Visual perception is one of the cognitive functions often impaired in children with cerebral palsy (CP). The aim of this systematic literature review was to assess the frequency of visual-perceptual impairment (VPI) and its relationship with patient characteristics. Eligible studies were relevant papers assessing visual perception with five common standardized assessment instruments in children with CP published from January 1990 to August 2011. Of the 84 studies selected, 15 were retained. In children with CP, the proportion of VPI ranged from 40% to 50% and the mean visual perception quotient from 70 to 90. None of the studies reported a significant influence of CP subtype, IQ level, side of motor impairment, neuro-ophthalmological outcomes, or seizures. The severity of neuroradiological lesions seemed associated with VPI. The influence of prematurity was controversial, but a lower gestational age was more often associated with lower visual motor skills than with decreased visual-perceptual abilities. The impairment of visual perception in children with CP should be considered a core disorder within the CP syndrome. Further research, including a more systematic approach to neuropsychological testing, is needed to explore the specific impact of CP subgroups and of neuroradiological features on visual-perceptual development. © 2015 The Authors. Developmental Medicine & Child Neurology © 2015 Mac Keith Press.

  15. Visual cues for data mining

    Science.gov (United States)

    Rogowitz, Bernice E.; Rabenhorst, David A.; Gerth, John A.; Kalin, Edward B.

    1996-04-01

    This paper describes a set of visual techniques, based on principles of human perception and cognition, which can help users analyze and develop intuitions about tabular data. Collections of tabular data are widely available, including, for example, multivariate time series data, customer satisfaction data, stock market performance data, multivariate profiles of companies and individuals, and scientific measurements. In our approach, we show how visual cues can help users perform a number of data mining tasks, including identifying correlations and interaction effects, finding clusters and understanding the semantics of cluster membership, identifying anomalies and outliers, and discovering multivariate relationships among variables. These cues are derived from psychological studies on perceptual organization, visual search, perceptual scaling, and color perception. These visual techniques are presented as a complement to the statistical and algorithmic methods more commonly associated with these tasks, and provide an interactive interface for the human analyst.

  16. Measuring the Reader Self-Perceptions of Adolescents: Introducing the RSPS2

    Science.gov (United States)

    Henk, William A.; Marinak, Barbara A.; Melnick, Steven A.

    2013-01-01

    This paper introduces a new affective instrument for assessing the reader self-perceptions of students in grades seven through ten. The Reader Self-Perception Scale 2 (RSPS2) builds upon its predecessor, the RSPS, a tool that measures the reading efficacy beliefs of children in grades four through six. New items were created for the RSPS2 to…

  17. Timing in audiovisual speech perception: A mini review and new psychophysical data.

    Science.gov (United States)

    Venezia, Jonathan H; Thurman, Steven M; Matchin, William; George, Sahara E; Hickok, Gregory

    2016-02-01

    Recent influential models of audiovisual speech perception suggest that visual speech aids perception by generating predictions about the identity of upcoming speech sounds. These models place stock in the assumption that visual speech leads auditory speech in time. However, it is unclear whether and to what extent temporally-leading visual speech information contributes to perception. Previous studies exploring audiovisual-speech timing have relied upon psychophysical procedures that require artificial manipulation of cross-modal alignment or stimulus duration. We introduce a classification procedure that tracks perceptually relevant visual speech information in time without requiring such manipulations. Participants were shown videos of a McGurk syllable (auditory /apa/ + visual /aka/ = perceptual /ata/) and asked to perform phoneme identification (/apa/ yes-no). The mouth region of the visual stimulus was overlaid with a dynamic transparency mask that obscured visual speech in some frames but not others randomly across trials. Variability in participants' responses (~35 % identification of /apa/ compared to ~5 % in the absence of the masker) served as the basis for classification analysis. The outcome was a high resolution spatiotemporal map of perceptually relevant visual features. We produced these maps for McGurk stimuli at different audiovisual temporal offsets (natural timing, 50-ms visual lead, and 100-ms visual lead). Briefly, temporally-leading (~130 ms) visual information did influence auditory perception. Moreover, several visual features influenced perception of a single speech sound, with the relative influence of each feature depending on both its temporal relation to the auditory signal and its informational content.

  18. Timing in Audiovisual Speech Perception: A Mini Review and New Psychophysical Data

    Science.gov (United States)

    Venezia, Jonathan H.; Thurman, Steven M.; Matchin, William; George, Sahara E.; Hickok, Gregory

    2015-01-01

    Recent influential models of audiovisual speech perception suggest that visual speech aids perception by generating predictions about the identity of upcoming speech sounds. These models place stock in the assumption that visual speech leads auditory speech in time. However, it is unclear whether and to what extent temporally-leading visual speech information contributes to perception. Previous studies exploring audiovisual-speech timing have relied upon psychophysical procedures that require artificial manipulation of cross-modal alignment or stimulus duration. We introduce a classification procedure that tracks perceptually-relevant visual speech information in time without requiring such manipulations. Participants were shown videos of a McGurk syllable (auditory /apa/ + visual /aka/ = perceptual /ata/) and asked to perform phoneme identification (/apa/ yes-no). The mouth region of the visual stimulus was overlaid with a dynamic transparency mask that obscured visual speech in some frames but not others randomly across trials. Variability in participants' responses (∼35% identification of /apa/ compared to ∼5% in the absence of the masker) served as the basis for classification analysis. The outcome was a high resolution spatiotemporal map of perceptually-relevant visual features. We produced these maps for McGurk stimuli at different audiovisual temporal offsets (natural timing, 50-ms visual lead, and 100-ms visual lead). Briefly, temporally-leading (∼130 ms) visual information did influence auditory perception. Moreover, several visual features influenced perception of a single speech sound, with the relative influence of each feature depending on both its temporal relation to the auditory signal and its informational content. PMID:26669309

  19. On disturbed time continuity in schizophrenia: an elementary impairment in visual perception?

    Directory of Open Access Journals (Sweden)

    Anne eGiersch

    2013-05-01

    Full Text Available Schizophrenia is associated with a series of visual perception impairments, which might impact on the patients’ every day life and be related to clinical symptoms. However, the heterogeneity of the visual disorders make it a challenge to understand both the mechanisms and the consequences of these impairments, i.e. the way patients experience the outer world. Based on earlier psychiatry literature, we argue that issues regarding time might shed a new light on the disorders observed in patients with schizophrenia. We will briefly review the mechanisms involved in the sense of time continuity and clinical evidence that they are impaired in patients with schizophrenia. We will then summarize a recent experimental approach regarding the coding of time-event structure in time, namely the ability to discriminate between simultaneous and asynchronous events. The use of an original method of analysis allowed us to distinguish between explicit and implicit judgements of synchrony. We showed that for SOAs below 20 ms neither patients nor controls fuse events in time. On the contrary subjects distinguish events at an implicit level even when judging them as synchronous. In addition, the implicit responses of patients and controls differ qualitatively. It is as if controls always put more weight on the last occurred event, whereas patients have a difficulty to follow events in time at an implicit level. In patients, there is a clear dissociation between results at short and large asynchronies, that suggest selective mechanisms for the implicit coding of time-event structure. These results might explain the disruption of the sense of time continuity in patients. We argue that this line of research might also help us to better understand the mechanisms of the visual impairments in patients and how they see their environment.

  20. Development of a Computerized Visual Search Test

    Science.gov (United States)

    Reid, Denise; Babani, Harsha; Jon, Eugenia

    2009-01-01

    Visual attention and visual search are the features of visual perception, essential for attending and scanning one's environment while engaging in daily occupations. This study describes the development of a novel web-based test of visual search. The development information including the format of the test will be described. The test was designed…

  1. Computational modeling of unsteady third-grade fluid flow over a vertical cylinder: A study of heat transfer visualization

    Science.gov (United States)

    Reddy, G. Janardhana; Hiremath, Ashwini; Kumar, Mahesh

    2018-03-01

    The present paper aims to investigate the effect of Prandtl number for unsteady third-grade fluid flow over a uniformly heated vertical cylinder using Bejan's heat function concept. The mathematical model of this problem is given by highly time-dependent non-linear coupled equations and are resolved by an efficient unconditionally stable implicit scheme. The time histories of average values of momentum and heat transport coefficients as well as the steady-state flow variables are displayed graphically for distinct values of non-dimensional control parameters arising in the system. As the non-dimensional parameter value gets amplified, the time taken for the fluid flow variables to attain the time-independent state is decreasing. The dimensionless heat function values are closely associated with an overall rate of heat transfer. Thermal energy transfer visualization implies that the heat function contours are compact in the neighborhood of the leading edge of the hot cylindrical wall. It is noticed that the deviations of flow-field variables from the hot wall for a non-Newtonian third-grade fluid flow are significant compared to the usual Newtonian fluid flow.

  2. Benefits of Single-Gender Education: Perceptions of Middle Grade Teachers

    Science.gov (United States)

    Nattress, Deborah A.

    2013-01-01

    This quantitative study used descriptive statistics to evaluate data obtained from 179 middle grade teachers, grades 5-9, currently working in a single-gender environment, including public, private, and charter schools, with regard to the academic and behavioral benefits of single-gender education. The study used a survey created by Dr. John Fry…

  3. EFFECTIVENESS OF ADJUVANT USE OF POSTERIOR MANUAL COMPRESSION WITH GRADED COMPRESSION IN THE SONOGRAPHIC DIAGNOSIS OF ACUTE APPENDICITIS

    Directory of Open Access Journals (Sweden)

    Senthilnathan V

    2018-01-01

    Full Text Available BACKGROUND Diagnosing appendicitis by Graded Compression Ultrasonogram is a difficult task because of limiting factors such as operator– dependent technique, retrocaecal location of the appendix and patient obesity. Posterior manual compression technique visualizes the appendix better in the Grey-scale Ultrasonogram. The Aim of this study is to determine the accuracy of ultrasound in detecting or excluding acute appendicitis and to evaluate the usefulness of the adjuvant use of posterior manual compression technique in visualization of the appendix and in the diagnosis of acute appendicitis MATERIALS AND METHODS This prospective study involved a total of 240 patients in all age groups and both sexes. All these patients underwent USG for suspected appendicitis. Ultrasonography was performed with transverse and longitudinal graded compression sonography. If the appendix is not visualized on graded compression sonography, posterior manual compression technique was used to further improve the detection of appendix. RESULTS The vermiform appendix was visualized in 185 patients (77.1% out of 240 patients with graded compression alone. 55 out of 240 patients whose appendix could not be visualized by graded compression alone were subjected to both graded followed by posterior manual compression technique among that Appendix was visualized in 43 patients on posterior manual compression technique amounting to 78.2% of cases, Appendix could not be visualized in the remaining 12 patients (21.8% out of 55. CONCLUSION Combined method of graded compression with posterior manual compression technique is better than the graded compression technique alone in diagnostic accuracy and detection rate of the vermiform appendix.

  4. Moving Stimuli Facilitate Synchronization But Not Temporal Perception.

    Science.gov (United States)

    Silva, Susana; Castro, São Luís

    2016-01-01

    Recent studies have shown that a moving visual stimulus (e.g., a bouncing ball) facilitates synchronization compared to a static stimulus (e.g., a flashing light), and that it can even be as effective as an auditory beep. We asked a group of participants to perform different tasks with four stimulus types: beeps, siren-like sounds, visual flashes (static) and bouncing balls. First, participants performed synchronization with isochronous sequences (stimulus-guided synchronization), followed by a continuation phase in which the stimulus was internally generated (imagery-guided synchronization). Then they performed a perception task, in which they judged whether the final part of a temporal sequence was compatible with the previous beat structure (stimulus-guided perception). Similar to synchronization, an imagery-guided variant was added, in which sequences contained a gap in between (imagery-guided perception). Balls outperformed flashes and matched beeps (powerful ball effect) in stimulus-guided synchronization but not in perception (stimulus- or imagery-guided). In imagery-guided synchronization, performance accuracy decreased for beeps and balls, but not for flashes and sirens. Our findings suggest that the advantages of moving visual stimuli over static ones are grounded in action rather than perception, and they support the hypothesis that the sensorimotor coupling mechanisms for auditory (beeps) and moving visual stimuli (bouncing balls) overlap.

  5. Leukocyte Image Segmentation Using Novel Saliency Detection Based on Positive Feedback of Visual Perception

    Directory of Open Access Journals (Sweden)

    Chen Pan

    2018-01-01

    Full Text Available This paper presents a novel method for salient object detection in nature image by simulating microsaccades in fixational eye movements. Due to a nucleated cell usually stained that is salient obviously, the proposed method is suitable to segment nucleated cell. Firstly, the existing fixation prediction method is utilized to produce an initial fixation area. Followed EPELM (ensemble of polyharmonic extreme learning machine is trained on-line by the pixels sampling from the fixation and nonfixation area. Then the model of EPELM could be used to classify image pixels to form new binary fixation area. Depending upon the updated fixation area, the procedure of “pixel sampling-learning-classification” could be performed iteratively. If the previous binary fixation area and the latter one were similar enough in iteration, it indicates that the perception is saturated and the loop should be terminated. The binary output in iteration could be regarded as a kind of visual stimulation. So the multiple outputs of visual stimuli can be accumulated to form a new saliency map. Experiments on three image databases show the validity of our method. It can segment nucleated cells successfully in different imaging conditions.

  6. Psycho acoustical Measures in Individuals with Congenital Visual Impairment.

    Science.gov (United States)

    Kumar, Kaushlendra; Thomas, Teenu; Bhat, Jayashree S; Ranjan, Rajesh

    2017-12-01

    In congenital visual impaired individuals one modality is impaired (visual modality) this impairment is compensated by other sensory modalities. There is evidence that visual impaired performed better in different auditory task like localization, auditory memory, verbal memory, auditory attention, and other behavioural tasks when compare to normal sighted individuals. The current study was aimed to compare the temporal resolution, frequency resolution and speech perception in noise ability in individuals with congenital visual impaired and normal sighted. Temporal resolution, frequency resolution, and speech perception in noise were measured using MDT, GDT, DDT, SRDT, and SNR50 respectively. Twelve congenital visual impaired participants with age range of 18 to 40 years were taken and equal in number with normal sighted participants. All the participants had normal hearing sensitivity with normal middle ear functioning. Individual with visual impairment showed superior threshold in MDT, SRDT and SNR50 as compared to normal sighted individuals. This may be due to complexity of the tasks; MDT, SRDT and SNR50 are complex tasks than GDT and DDT. Visual impairment showed superior performance in auditory processing and speech perception with complex auditory perceptual tasks.

  7. Use of Collage Technique in Modern Art Perceptions of Visual Arts Teacher Candidates: Action Research

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    Görkem Utku ALPARSLAN

    2018-01-01

    Full Text Available The purpose of the research is to demonstrate the contribution of the collage technique to modern art perceptions of visual arts teacher candidates. Research has been designed in the form of an action research from qualitative research methods. The study was conducted for eight weeks. The data of the study, the student journals and the pictures of the students before, during and after the application were collected and evaluated by rubric. In the study, it was found that students 'pictures of rubbing their images with rubbing techniques developed as a result of modern formal intellectual and formative reflection and as a result of the descriptive analysis of qualitative data, students' awareness of modern visual intellectual and formal foundations and collage technique increased. As a result of the research, the level of skill of expressing modern formal expression was observed in the students' work and it was determined that the awareness of students about the formal and intellectual structure of modern picture and collage technique increased in the frame of originality, criticism and creativity.

  8. The Influence of Auditory Information on Visual Size Adaptation.

    Science.gov (United States)

    Tonelli, Alessia; Cuturi, Luigi F; Gori, Monica

    2017-01-01

    Size perception can be influenced by several visual cues, such as spatial (e.g., depth or vergence) and temporal contextual cues (e.g., adaptation to steady visual stimulation). Nevertheless, perception is generally multisensory and other sensory modalities, such as auditory, can contribute to the functional estimation of the size of objects. In this study, we investigate whether auditory stimuli at different sound pitches can influence visual size perception after visual adaptation. To this aim, we used an adaptation paradigm (Pooresmaeili et al., 2013) in three experimental conditions: visual-only, visual-sound at 100 Hz and visual-sound at 9,000 Hz. We asked participants to judge the size of a test stimulus in a size discrimination task. First, we obtained a baseline for all conditions. In the visual-sound conditions, the auditory stimulus was concurrent to the test stimulus. Secondly, we repeated the task by presenting an adapter (twice as big as the reference stimulus) before the test stimulus. We replicated the size aftereffect in the visual-only condition: the test stimulus was perceived smaller than its physical size. The new finding is that we found the auditory stimuli have an effect on the perceived size of the test stimulus after visual adaptation: low frequency sound decreased the effect of visual adaptation, making the stimulus perceived bigger compared to the visual-only condition, and contrarily, the high frequency sound had the opposite effect, making the test size perceived even smaller.

  9. Distributed processing in bistable perception

    NARCIS (Netherlands)

    Knapen, T.H.J.

    2007-01-01

    A very incisive way of studying visual awareness and the mechanisms that underlie it, it to use bistable perception. In bistable perception, an observer's perceptual state alternates between one interpretation and its mutually exclusive counterpart while the stimulus remains the same. This gives us

  10. Adolescentes portadores de deficiência visual: percepções sobre sexualidade Adolescentes portadores de deficiencia visual: percepciones sobre sexualidad Visually impaired teenagers: perceptions on sexuality

    Directory of Open Access Journals (Sweden)

    Giovana Raquel de Moura

    2006-04-01

    Full Text Available Este estudo é de natureza exploratório-descritiva e teve por objetivo conhecer as percepções dos adolescentes portadores de deficiência visual acerca de sua sexualidade. Os dados foram coletados nos meses de maio e junho de 2004, por meio de entrevistas semi-estruturadas com oito adolescentes deficientes visuais freqüentadores de uma instituição em Porto Alegre, RS, Brasil. As informações foram submetidas à técnica de análise de conteúdo de Bardin, das quais emergiram duas categorias principais: Sexualidade e Modificações sociocomportamentais. Observou-se que os sujeitos carecem de informações a respeito de diversas questões que envolvem a sexualidade como conhecimentos morfofisiológicos, psicoafetivos, cuidados preventivos. Os profissionais da saúde, principalmente enfermeiros, necessitam de preparo para abordar essas questões e contribuir para o desenvolvimento da sexualidade saudável desses indivíduos.Este estudio exploratorio-descriptivo tuvo por objetivo conocer las percepciones de adolescentes portadores de deficiencia visual acerca de su sexualidad. Los datos fueron recogidos en mayo y junio de 2004, mediante entrevistas semiestructuradas con ocho adolescentes deficientes visuales que frecuentan una institución en Porto Alegre, Rio Grande do Sul, Brasil. Las informaciones fueron sometidas a la técnica de análisis de contenido según Bardin. De ellas emergieron dos categorías principales: Sexualidad y Modificaciones sociocomportamentales. Se puede observar que a los sujetos les faltan informaciones con respecto a diversas cuestiones que involucran la sexualidad, tales como conocimientos morfofisiológicos, psicoafectivos y de cuidados preventivos. Los profesionales de la salud, principalmente los enfermeros, necesitan de preparación para abordar esas cuestiones y contribuir al desarrollo de una sexualidad saludable para esos individuos.This exploratory-descriptive study aimed to reveal perceptions of visually

  11. Visual processing speed in old age.

    Science.gov (United States)

    Habekost, Thomas; Vogel, Asmus; Rostrup, Egill; Bundesen, Claus; Kyllingsbaek, Søren; Garde, Ellen; Ryberg, Charlotte; Waldemar, Gunhild

    2013-04-01

    Mental speed is a common concept in theories of cognitive aging, but it is difficult to get measures of the speed of a particular psychological process that are not confounded by the speed of other processes. We used Bundesen's (1990) Theory of Visual Attention (TVA) to obtain specific estimates of processing speed in the visual system controlled for the influence of response latency and individual variations of the perception threshold. A total of 33 non-demented old people (69-87 years) were tested for the ability to recognize briefly presented letters. Performance was analyzed by the TVA model. Visual processing speed decreased approximately linearly with age and was on average halved from 70 to 85 years. Less dramatic aging effects were found for the perception threshold and the visual apprehension span. In the visual domain, cognitive aging seems to be most clearly related to reductions in processing speed. © 2012 The Authors. Scandinavian Journal of Psychology © 2012 The Scandinavian Psychological Associations.

  12. Teachers' and students' perceptions of seventh- and eighth-grade science education in a selected Seventh-day Adventist Union Conference

    Science.gov (United States)

    Sargeant, Marcel Andre Almont

    Problem. Science education has long been a great concern in the United States, where less than one-third of the students perform at or above the proficient level. The purpose of this study was to investigate the status of the science program in a selected Union Conference of the Seventh-day Adventist school system. Specifically, this study investigated the perceptions of teachers and students regarding the extent to which the science program meets the criteria of the National Commission on Mathematics and Science Teaching for the 21st century and to what extent these criteria are related to academic performance as indicated by Iowa Test of Basic Skills (ITBS) science scores. Method. Two questionnaires designed by the researcher were used to get responses from 424 students in seventh and eighth grades and 68 teachers to see how this school system compares to the criteria of National Commission on Mathematics and Science Teaching for the 21 st century. Three classroom configurations were investigated in this study, namely: (a) multigrade, (b) two-grade, and (c) single-grade. Crosstabulation, one-way analysis of variance, Kruskal-Wallis test, and linear regression were used to analyze the four research questions of this study. Results. The single-grade classroom configuration received a better rating for the science criteria (p century. Conclusions. The differences in teaching practices explained the discrepancies in the three classroom configurations. Schools can therefore develop policies and strategies to improve the practices in the teaching and learning process in science education that were identified as being deficient by the criteria of National Commission on Mathematics and Science Teaching for the 21st century.

  13. Comparison of the reliability of two hydronephrosis grading systems: The Society for Foetal Urology grading system vs. the Onen grading system

    International Nuclear Information System (INIS)

    Kim, S.-Y.; Kim, M.-J.; Yoon, C.S.; Lee, M.S.; Han, K.H.; Lee, M.-J.

    2013-01-01

    Aim: To compare the reliability of the conventional ultrasonography grading system for hydronephrosis as suggested by the Society for Fetal Urology (SFU) in 1993 and that developed by Onen in 2007. Materials and methods: One hundred and eighty kidneys in 90 paediatric patients were assessed by four radiologists using each of the two grading systems twice. The SFU system was graded 0–4 (0 = no hydronephrosis; 1 = visualized only renal pelvis; 2 = plus a few caliceal dilatation; 3 = all calyceal dilatation; 4 = plus parenchymal thinning). The Onen system was graded 0–4 (0 = no hydronephrosis; 1 = only renal pelvic dilatation; 2 = plus caliceal dilatation; 3 = plus 50% renal parenchymal loss). Cohen's kappa statistic was used to estimate intra- and interobserver agreement. The weighted least-squares approach was used to compare the intra-observer agreement, and bootstrapping was used to compare the interobserver agreement between the two systems. Results: Intra-observer agreement was substantial to almost perfect in both the SFU (κ 0.79–0.95) and the Onen (κ 0.66–0.97) grading system without difference. The overall interobserver agreement was substantial in both the SFU (κ 0.61–0.68) and the Onen (κ 0.66–0.76) grading system. However, interobserver agreement was fair to moderate for SFU grades 1 and 2 and Onen grades 2 and 3. Conclusion: Both the SFU and Onen grading system are reliable with good intra- and interobserver agreement. However, decreased interobserver agreement was demonstrated for SFU grades 1 and 2 and Onen grades 2 and 3

  14. Children's perceptions of school-based violence.

    Science.gov (United States)

    Gumpel, T P; Meadan, H

    2000-09-01

    An important first step in understanding school-based violence is understanding children's subjective perceptions of the phenomena. Understanding these perceptions is likely to be a major factor in determining the integrity of both prevalence and intervention studies. We investigated how elementary and secondary aged children perceived school-based violence. A sample of 979 children from a nested random sample of elementary (grades 3-6) and middle school (grades 7-8) classrooms in Jerusalem participated in this study. To understand children's perception of school violence, we used an instrument composed of 19 dichotomous items, each presenting a one-line description of a behaviour, which the respondent would define as either 'intentionally harmful' or not. Eighth graders were significantly less likely to label the behaviours described as violent compared to all other grades; and seventh graders were less likely as compared to third, fourth and fifth graders; also, some between-gender differences were found. The respondents often view the behaviours described as intentional and aggressive; this finding should serve as an impetu