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Sample records for perceptual load theory

  1. Load theory behind the wheel; perceptual and cognitive load effects.

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    Murphy, Gillian; Greene, Ciara M

    2017-09-01

    Perceptual Load Theory has been proposed as a resolution to the longstanding early versus late selection debate in cognitive psychology. There is much evidence in support of Load Theory but very few applied studies, despite the potential for the model to shed light on everyday attention and distraction. Using a driving simulator, the effect of perceptual and cognitive load on drivers' visual search was assessed. The findings were largely in line with Load Theory, with reduced distractor processing under high perceptual load, but increased distractor processing under high cognitive load. The effect of load on driving behaviour was also analysed, with significant differences in driving behaviour under perceptual and cognitive load. In addition, the effect of perceptual load on drivers' levels of awareness was investigated. High perceptual load significantly increased inattentional blindness and deafness, for stimuli that were both relevant and irrelevant to driving. High perceptual load also increased RTs to hazards. The current study helps to advance Load Theory by illustrating its usefulness outside of traditional paradigms. There are also applied implications for driver safety and roadway design, as the current study suggests that perceptual and cognitive load are important factors in driver attention. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. Conceptual and methodological concerns in the theory of perceptual load.

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    Benoni, Hanna; Tsal, Yehoshua

    2013-01-01

    The present paper provides a short critical review of the theory of perceptual load. It closely examines the basic tenets and assumptions of the theory and identifies major conceptual and methodological problems that have been largely ignored in the literature. The discussion focuses on problems in the definition of the concept of perceptual load, on the circularity in the characterization and manipulation of perceptual load and the confusion between the concept of perceptual load and its operationalization. The paper also selectively reviews evidence supporting the theory as well as inconsistent evidence which proposed alternative dominant factors influencing the efficacy of attentional selection.

  3. Conceptual and Methodological Concerns in the Theory of Perceptual Load

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    Hanna eBenoni

    2013-08-01

    Full Text Available The present paper provides a short critical review of the theory of perceptual load. It closely examines the basic tenets and assumptions of the theory and identifies major conceptual and methodological problems that have been largely ignored in the literature. The discussion focuses on problems in the definition of the concept of perceptual load, on the circularity in the characterization and manipulation of perceptual load and the confusion between the concept of perceptual load and its operationalization. The paper also selectively reviews evidence supporting the theory as well as inconsistent evidence which proposed alternative dominant factors influencing the efficacy of attentional selection.

  4. Competition explains limited attention and perceptual resources: implications for perceptual load and dilution theories

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    Paige E. Scalf

    2013-05-01

    Full Text Available Both perceptual load theory and dilution theory purport to explain when and why task-irrelevant information, or so-called distractors are processed. Central to both explanations is the notion of limited resources, although the theories differ in the precise way in which those limitations affect distractor processing. We have recently proposed a neurally plausible explanation of limited resources in which neural competition among stimuli hinders their representation in the brain. This view of limited capacity can also explain distractor processing, whereby the competitive interactions and bias imposed to resolve the competition determine the extent to which a distractor is processed. This idea is compatible with aspects of both perceptual load and dilution models of distractor processing, but also serves to highlight their differences. Here we review the evidence in favor of a biased competition view of limited resources and relate these ideas to both classic perceptual load theory and dilution theory.

  5. Competition explains limited attention and perceptual resources: implications for perceptual load and dilution theories.

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    Scalf, Paige E; Torralbo, Ana; Tapia, Evelina; Beck, Diane M

    2013-01-01

    Both perceptual load theory and dilution theory purport to explain when and why task-irrelevant information, or so-called distractors are processed. Central to both explanations is the notion of limited resources, although the theories differ in the precise way in which those limitations affect distractor processing. We have recently proposed a neurally plausible explanation of limited resources in which neural competition among stimuli hinders their representation in the brain. This view of limited capacity can also explain distractor processing, whereby the competitive interactions and bias imposed to resolve the competition determine the extent to which a distractor is processed. This idea is compatible with aspects of both perceptual load and dilution models of distractor processing, but also serves to highlight their differences. Here we review the evidence in favor of a biased competition view of limited resources and relate these ideas to both classic perceptual load theory and dilution theory.

  6. Processing Capacity under Perceptual and Cognitive Load: A Closer Look at Load Theory

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    Fitousi, Daniel; Wenger, Michael J.

    2011-01-01

    Variations in perceptual and cognitive demands (load) play a major role in determining the efficiency of selective attention. According to load theory (Lavie, Hirst, Fockert, & Viding, 2004) these factors (a) improve or hamper selectivity by altering the way resources (e.g., processing capacity) are allocated, and (b) tap resources rather than…

  7. Effect of perceptual load on conceptual processing: an extension of Vermeulen's theory.

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    Xie, Jiushu; Wang, Ruiming; Sun, Xun; Chang, Song

    2013-10-01

    The effect of color and shape load on conceptual processing was studied. Perceptual load effects have been found in visual and auditory conceptual processing, supporting the theory of embodied cognition. However, whether different types of visual concepts, such as color and shape, share the same perceptual load effects is unknown. In the current experiment, 32 participants were administered simultaneous perceptual and conceptual tasks to assess the relation between perceptual load and conceptual processing. Keeping color load in mind obstructed color conceptual processing. Hence, perceptual processing and conceptual load shared the same resources, suggesting embodied cognition. Color conceptual processing was not affected by shape pictures, indicating that different types of properties within vision were separate.

  8. Attentional selection within and across hemispheres: implications for the perceptual load theory.

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    Wei, Ping; Kang, Guanlan; Zhou, Xiaolin

    2013-03-01

    The perceptual load of a given task affects attentional selection, with the selection occurring earlier when the load is high and later when the load is low. Recent evidence suggests that local competitive interaction may underlie the perceptual load effect and determine to what extent a task-irrelevant distractor is processed. Here, we asked participants to search for a target bar among homogeneously oriented bars (the low load conditions) or heterogeneously oriented bars (the high load conditions) in the central display, while ignoring a congruent or incongruent flanker bar presented to the left or right side of the central display, or a bar presented at one of the six positions outer to the central display. Importantly, we differentiated conditions in which the target in the central display and the peripheral flanker was presented within the same hemifield or across different hemifields. Results showed a significant flanker effect for the low load condition, but not for the high load condition, when the target and the flanker were across hemifields. However, when the target and the flanker were presented within the same hemifield, there was no flanker effect for either low or high load conditions. These findings demonstrate that the ability to ignore the task-irrelevant distractor is affected by local competition within hemisphere and that the perceptual load theory needs to be supplemented with detailed analysis of cognitive processes and mechanisms underlying the consumption of attentional resources.

  9. Auditory perceptual load: A review.

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    Murphy, Sandra; Spence, Charles; Dalton, Polly

    2017-09-01

    Selective attention is a crucial mechanism in everyday life, allowing us to focus on a portion of incoming sensory information at the expense of other less relevant stimuli. The circumstances under which irrelevant stimuli are successfully ignored have been a topic of scientific interest for several decades now. Over the last 20 years, the perceptual load theory (e.g. Lavie, 1995) has provided one robust framework for understanding these effects within the visual modality. The suggestion is that successful selection depends on the perceptual demands imposed by the task-relevant information. However, less research has addressed the question of whether the same principles hold in audition and, to date, the existing literature provides a mixed picture. Here, we review the evidence for and against the applicability of perceptual load theory in hearing, concluding that this question still awaits resolution. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Effect of practice on perceptual load

    OpenAIRE

    Mejia-Ramirez, Manuel

    2013-01-01

    Within attention studies, Lavie's load theory (Lavie & Tsal, 1994; Lavie, Hirst, de Fockert, & Viding, 2004) presented an account that could settle the question whether attention selects stimuli to be processed at an early or late stage of cognitive processing. This theory relied on the concepts of "perceptual load" and "attentional capacity", proposing that attentional resources are automatically allocated to stimuli, but when the perceptual load of the stimuli exceeds person's capacity, tas...

  11. Attentional capture under high perceptual load.

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    Cosman, Joshua D; Vecera, Shaun P

    2010-12-01

    Attentional capture by abrupt onsets can be modulated by several factors, including the complexity, or perceptual load, of a scene. We have recently demonstrated that observers are less likely to be captured by abruptly appearing, task-irrelevant stimuli when they perform a search that is high, as opposed to low, in perceptual load (Cosman & Vecera, 2009), consistent with perceptual load theory. However, recent results indicate that onset frequency can influence stimulus-driven capture, with infrequent onsets capturing attention more often than did frequent onsets. Importantly, in our previous task, an abrupt onset was present on every trial, and consequently, attentional capture might have been affected by both onset frequency and perceptual load. In the present experiment, we examined whether onset frequency influences attentional capture under conditions of high perceptual load. When onsets were presented frequently, we replicated our earlier results; attentional capture by onsets was modulated under conditions of high perceptual load. Importantly, however, when onsets were presented infrequently, we observed robust capture effects. These results conflict with a strong form of load theory and, instead, suggest that exposure to the elements of a task (e.g., abrupt onsets) combines with high perceptual load to modulate attentional capture by task-irrelevant information.

  12. Perceptual Load Influences Selective Attention across Development

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    Couperus, Jane W.

    2011-01-01

    Research suggests that visual selective attention develops across childhood. However, there is relatively little understanding of the neurological changes that accompany this development, particularly in the context of adult theories of selective attention, such as N. Lavie's (1995) perceptual load theory of attention. This study examined visual…

  13. Evaluative pressure overcomes perceptual load effects.

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    Normand, Alice; Autin, Frédérique; Croizet, Jean-Claude

    2015-06-01

    Perceptual load has been found to be a powerful bottom-up determinant of distractibility, with high perceptual load preventing distraction by any irrelevant information. However, when under evaluative pressure, individuals exert top-down attentional control by giving greater weight to task-relevant features, making them more distractible from task-relevant distractors. One study tested whether the top-down modulation of attention under evaluative pressure overcomes the beneficial bottom-up effect of high perceptual load on distraction. Using a response-competition task, we replicated previous findings that high levels of perceptual load suppress task-relevant distractor response interference, but only for participants in a control condition. Participants under evaluative pressure (i.e., who believed their intelligence was assessed) showed interference from task-relevant distractor at all levels of perceptual load. This research challenges the assumptions of the perceptual load theory and sheds light on a neglected determinant of distractibility: the self-relevance of the performance situation in which attentional control is solicited.

  14. The effects of interstimulus interval on event-related indices of attention: an auditory selective attention test of perceptual load theory.

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    Gomes, Hilary; Barrett, Sophia; Duff, Martin; Barnhardt, Jack; Ritter, Walter

    2008-03-01

    We examined the impact of perceptual load by manipulating interstimulus interval (ISI) in two auditory selective attention studies that varied in the difficulty of the target discrimination. In the paradigm, channels were separated by frequency and target/deviant tones were softer in intensity. Three ISI conditions were presented: fast (300ms), medium (600ms) and slow (900ms). Behavioral (accuracy and RT) and electrophysiological measures (Nd, P3b) were observed. In both studies, participants evidenced poorer accuracy during the fast ISI condition than the slow suggesting that ISI impacted task difficulty. However, none of the three measures of processing examined, Nd amplitude, P3b amplitude elicited by unattended deviant stimuli, or false alarms to unattended deviants, were impacted by ISI in the manner predicted by perceptual load theory. The prediction based on perceptual load theory, that there would be more processing of irrelevant stimuli under conditions of low as compared to high perceptual load, was not supported in these auditory studies. Task difficulty/perceptual load impacts the processing of irrelevant stimuli in the auditory modality differently than predicted by perceptual load theory, and perhaps differently than in the visual modality.

  15. The Role of Perceptual Load in Inattentional Blindness

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    Cartwright-Finch, Ula; Lavie, Nilli

    2007-01-01

    Perceptual load theory offers a resolution to the long-standing early vs. late selection debate over whether task-irrelevant stimuli are perceived, suggesting that irrelevant perception depends upon the perceptual load of task-relevant processing. However, previous evidence for this theory has relied on RTs and neuroimaging. Here we tested the…

  16. Perceptual Load Affects Eyewitness Accuracy and Susceptibility to Leading Questions

    OpenAIRE

    Murphy, Gillian; Greene, Ciara M.

    2016-01-01

    Load Theory (Lavie, 1995, 2005) states that the level of perceptual load in a task (i.e., the amount of information involved in processing task-relevant stimuli) determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to report seeing obvious objects, it is conceivable that load may also impair memory for the scene. The ...

  17. Perceptual Load Affects Eyewitness Accuracy & Susceptibility to Leading Questions

    OpenAIRE

    Gillian Murphy; Ciara Mary Greene

    2016-01-01

    Load Theory (Lavie, 1995; 2005) states that the level of perceptual load in a task (i.e. the amount of information involved in processing task-relevant stimuli) determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to report seeing obvious objects, it is conceivable that load may also impair memory for the scene. The c...

  18. Attentional sets influence perceptual load effects, but not dilution effects.

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    Benoni, Hanna; Zivony, Alon; Tsal, Yehoshua

    2014-01-01

    Perceptual load theory [Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Performance, 21, 451-468.; Lavie, N., & Tsal, Y. (1994) Perceptual load as a major determinant of the locus of selection in visual attention. Perception & Psychophysics, 56, 183-197.] proposes that interference from distractors can only be avoided in situations of high perceptual load. This theory has been supported by blocked design manipulations separating low load (when the target appears alone) and high load (when the target is embedded among neutral letters). Tsal and Benoni [(2010a). Diluting the burden of load: Perceptual load effects are simply dilution effects. Journal of Experimental Psychology: Human Perception and Performance, 36, 1645-1656.; Benoni, H., & Tsal, Y. (2010). Where have we gone wrong? Perceptual load does not affect selective attention. Vision Research, 50, 1292-1298.] have recently shown that these manipulations confound perceptual load with "dilution" (the mere presence of additional heterogeneous items in high-load situations). Theeuwes, Kramer, and Belopolsky [(2004). Attentional set interacts with perceptual load in visual search. Psychonomic Bulletin & Review, 11, 697-702.] independently questioned load theory by suggesting that attentional sets might also affect distractor interference. When high load and low load were intermixed, and participants could not prepare for the presentation that followed, both the low-load and high-load trials showed distractor interference. This result may also challenge the dilution account, which proposes a stimulus-driven mechanism. In the current study, we presented subjects with both fixed and mixed blocks, including a mix of dilution trials with low-load trials and with high-load trials. We thus separated the effect of dilution from load and tested the influence of attentional sets on each component. The results revealed that whereas

  19. Perceptual load-dependent neural correlates of distractor interference inhibition.

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    Jiansong Xu

    2011-01-01

    Full Text Available The load theory of selective attention hypothesizes that distractor interference is suppressed after perceptual processing (i.e., in the later stage of central processing at low perceptual load of the central task, but in the early stage of perceptual processing at high perceptual load. Consistently, studies on the neural correlates of attention have found a smaller distractor-related activation in the sensory cortex at high relative to low perceptual load. However, it is not clear whether the distractor-related activation in brain regions linked to later stages of central processing (e.g., in the frontostriatal circuits is also smaller at high rather than low perceptual load, as might be predicted based on the load theory.We studied 24 healthy participants using functional magnetic resonance imaging (fMRI during a visual target identification task with two perceptual loads (low vs. high. Participants showed distractor-related increases in activation in the midbrain, striatum, occipital and medial and lateral prefrontal cortices at low load, but distractor-related decreases in activation in the midbrain ventral tegmental area and substantia nigra (VTA/SN, striatum, thalamus, and extensive sensory cortices at high load.Multiple levels of central processing involving midbrain and frontostriatal circuits participate in suppressing distractor interference at either low or high perceptual load. For suppressing distractor interference, the processing of sensory inputs in both early and late stages of central processing are enhanced at low load but inhibited at high load.

  20. Perceptual load-dependent neural correlates of distractor interference inhibition.

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    Xu, Jiansong; Monterosso, John; Kober, Hedy; Balodis, Iris M; Potenza, Marc N

    2011-01-18

    The load theory of selective attention hypothesizes that distractor interference is suppressed after perceptual processing (i.e., in the later stage of central processing) at low perceptual load of the central task, but in the early stage of perceptual processing at high perceptual load. Consistently, studies on the neural correlates of attention have found a smaller distractor-related activation in the sensory cortex at high relative to low perceptual load. However, it is not clear whether the distractor-related activation in brain regions linked to later stages of central processing (e.g., in the frontostriatal circuits) is also smaller at high rather than low perceptual load, as might be predicted based on the load theory. We studied 24 healthy participants using functional magnetic resonance imaging (fMRI) during a visual target identification task with two perceptual loads (low vs. high). Participants showed distractor-related increases in activation in the midbrain, striatum, occipital and medial and lateral prefrontal cortices at low load, but distractor-related decreases in activation in the midbrain ventral tegmental area and substantia nigra (VTA/SN), striatum, thalamus, and extensive sensory cortices at high load. Multiple levels of central processing involving midbrain and frontostriatal circuits participate in suppressing distractor interference at either low or high perceptual load. For suppressing distractor interference, the processing of sensory inputs in both early and late stages of central processing are enhanced at low load but inhibited at high load.

  1. Perceptual load corresponds with factors known to influence visual search.

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    Roper, Zachary J J; Cosman, Joshua D; Vecera, Shaun P

    2013-10-01

    One account of the early versus late selection debate in attention proposes that perceptual load determines the locus of selection. Attention selects stimuli at a late processing level under low-load conditions but selects stimuli at an early level under high-load conditions. Despite the successes of perceptual load theory, a noncircular definition of perceptual load remains elusive. We investigated the factors that influence perceptual load by using manipulations that have been studied extensively in visual search, namely target-distractor similarity and distractor-distractor similarity. Consistent with previous work, search was most efficient when targets and distractors were dissimilar and the displays contained homogeneous distractors; search became less efficient when target-distractor similarity increased irrespective of display heterogeneity. Importantly, we used these same stimuli in a typical perceptual load task that measured attentional spillover to a task-irrelevant flanker. We found a strong correspondence between search efficiency and perceptual load; stimuli that generated efficient searches produced flanker interference effects, suggesting that such displays involved low perceptual load. Flanker interference effects were reduced in displays that produced less efficient searches. Furthermore, our results demonstrate that search difficulty, as measured by search intercept, has little bearing on perceptual load. We conclude that rather than be arbitrarily defined, perceptual load might be defined by well-characterized, continuous factors that influence visual search. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  2. The Role of Perceptual Load in Object Recognition

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    Lavie, Nilli; Lin, Zhicheng; Zokaei, Nahid; Thoma, Volker

    2009-01-01

    Predictions from perceptual load theory (Lavie, 1995, 2005) regarding object recognition across the same or different viewpoints were tested. Results showed that high perceptual load reduces distracter recognition levels despite always presenting distracter objects from the same view. They also showed that the levels of distracter recognition were…

  3. Perceptual load in sport and the heuristic value of the perceptual load paradigm in examining expertise-related perceptual-cognitive adaptations.

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    Furley, Philip; Memmert, Daniel; Schmid, Simone

    2013-03-01

    In two experiments, we transferred perceptual load theory to the dynamic field of team sports and tested the predictions derived from the theory using a novel task and stimuli. We tested a group of college students (N = 33) and a group of expert team sport players (N = 32) on a general perceptual load task and a complex, soccer-specific perceptual load task in order to extend the understanding of the applicability of perceptual load theory and further investigate whether distractor interference may differ between the groups, as the sport-specific processing task may not exhaust the processing capacity of the expert participants. In both, the general and the specific task, the pattern of results supported perceptual load theory and demonstrates that the predictions of the theory also transfer to more complex, unstructured situations. Further, perceptual load was the only determinant of distractor processing, as we neither found expertise effects in the general perceptual load task nor the sport-specific task. We discuss the heuristic utility of using response-competition paradigms for studying both general and domain-specific perceptual-cognitive adaptations.

  4. Perceptual Load Affects Eyewitness Accuracy & Susceptibility to Leading Questions

    Directory of Open Access Journals (Sweden)

    Gillian Murphy

    2016-08-01

    Full Text Available Load Theory (Lavie, 1995; 2005 states that the level of perceptual load in a task (i.e. the amount of information involved in processing task-relevant stimuli determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to report seeing obvious objects, it is conceivable that load may also impair memory for the scene. The current study is the first to assess the effect of perceptual load on eyewitness memory. Across three experiments (two video-based and one in a driving simulator, the effect of perceptual load on eyewitness memory was assessed. The results showed that eyewitnesses were less accurate under high load, in particular for peripheral details. For example, memory for the central character in the video was not affected by load but memory for a witness who passed by the window at the edge of the scene was significantly worse under high load. High load memories were also more open to suggestion, showing increased susceptibility to leading questions. High visual perceptual load also affected recall for auditory information, illustrating a possible cross-modal perceptual load effect on memory accuracy. These results have implications for eyewitness memory researchers and forensic professionals.

  5. Perceptual Load Affects Eyewitness Accuracy and Susceptibility to Leading Questions.

    Science.gov (United States)

    Murphy, Gillian; Greene, Ciara M

    2016-01-01

    Load Theory (Lavie, 1995, 2005) states that the level of perceptual load in a task (i.e., the amount of information involved in processing task-relevant stimuli) determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to report seeing obvious objects, it is conceivable that load may also impair memory for the scene. The current study is the first to assess the effect of perceptual load on eyewitness memory. Across three experiments (two video-based and one in a driving simulator), the effect of perceptual load on eyewitness memory was assessed. The results showed that eyewitnesses were less accurate under high load, in particular for peripheral details. For example, memory for the central character in the video was not affected by load but memory for a witness who passed by the window at the edge of the scene was significantly worse under high load. High load memories were also more open to suggestion, showing increased susceptibility to leading questions. High visual perceptual load also affected recall for auditory information, illustrating a possible cross-modal perceptual load effect on memory accuracy. These results have implications for eyewitness memory researchers and forensic professionals.

  6. Perceptual load interacts with stimulus processing across sensory modalities.

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    Klemen, J; Büchel, C; Rose, M

    2009-06-01

    According to perceptual load theory, processing of task-irrelevant stimuli is limited by the perceptual load of a parallel attended task if both the task and the irrelevant stimuli are presented to the same sensory modality. However, it remains a matter of debate whether the same principles apply to cross-sensory perceptual load and, more generally, what form cross-sensory attentional modulation in early perceptual areas takes in humans. Here we addressed these questions using functional magnetic resonance imaging. Participants undertook an auditory one-back working memory task of low or high perceptual load, while concurrently viewing task-irrelevant images at one of three object visibility levels. The processing of the visual and auditory stimuli was measured in the lateral occipital cortex (LOC) and auditory cortex (AC), respectively. Cross-sensory interference with sensory processing was observed in both the LOC and AC, in accordance with previous results of unisensory perceptual load studies. The present neuroimaging results therefore warrant the extension of perceptual load theory from a unisensory to a cross-sensory context: a validation of this cross-sensory interference effect through behavioural measures would consolidate the findings.

  7. Visual perceptual load induces inattentional deafness.

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    Macdonald, James S P; Lavie, Nilli

    2011-08-01

    In this article, we establish a new phenomenon of "inattentional deafness" and highlight the level of load on visual attention as a critical determinant of this phenomenon. In three experiments, we modified an inattentional blindness paradigm to assess inattentional deafness. Participants made either a low- or high-load visual discrimination concerning a cross shape (respectively, a discrimination of line color or of line length with a subtle length difference). A brief pure tone was presented simultaneously with the visual task display on a final trial. Failures to notice the presence of this tone (i.e., inattentional deafness) reached a rate of 79% in the high-visual-load condition, significantly more than in the low-load condition. These findings establish the phenomenon of inattentional deafness under visual load, thereby extending the load theory of attention (e.g., Lavie, Journal of Experimental Psychology. Human Perception and Performance, 25, 596-616, 1995) to address the cross-modal effects of visual perceptual load.

  8. Animacy, perceptual load, and inattentional blindness.

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    Calvillo, Dustin P; Jackson, Russell E

    2014-06-01

    Inattentional blindness is the failure to notice unexpected objects in a visual scene while engaging in an attention-demanding task. We examined the effects of animacy and perceptual load on inattentional blindness. Participants searched for a category exemplar under low or high perceptual load. On the last trial, the participants were exposed to an unexpected object that was either animate or inanimate. Unexpected objects were detected more frequently when they were animate rather than inanimate, and more frequently with low than with high perceptual loads. We also measured working memory capacity and found that it predicted the detection of unexpected objects, but only with high perceptual loads. The results are consistent with the animate-monitoring hypothesis, which suggests that animate objects capture attention because of the importance of the detection of animate objects in ancestral hunter-gatherer environments.

  9. Lightening the load: perceptual load impairs visual detection in typical adults but not in autism.

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    Remington, Anna M; Swettenham, John G; Lavie, Nilli

    2012-05-01

    Autism spectrum disorder (ASD) research portrays a mixed picture of attentional abilities with demonstrations of enhancements (e.g., superior visual search) and deficits (e.g., higher distractibility). Here we test a potential resolution derived from the Load Theory of Attention (e.g., Lavie, 2005). In Load Theory, distractor processing depends on the perceptual load of the task and as such can only be eliminated under high load that engages full capacity. We hypothesize that ASD involves enhanced perceptual capacity, leading to the superior performance and increased distractor processing previously reported. Using a signal-detection paradigm, we test this directly and demonstrate that, under higher levels of load, perceptual sensitivity was reduced in typical adults but not in adults with ASD. These findings confirm our hypothesis and offer a promising solution to the previous discrepancies by suggesting that increased distractor processing in ASD results not from a filtering deficit but from enhanced perceptual capacity.

  10. Beyond perceptual load and dilution: a review of the role of working memory in selective attention

    OpenAIRE

    de Fockert, Jan W.

    2013-01-01

    The perceptual load and dilution models differ fundamentally in terms of the proposed mechanism underlying variation in distractibility during different perceptual conditions. However, both models predict that distracting information can be processed beyond perceptual processing under certain conditions, a prediction that is well-supported by the literature. Load theory proposes that in such cases, where perceptual task aspects do not allow for sufficient attentional selectivity, the maintena...

  11. Diluting the Burden of Load: Perceptual Load Effects Are Simply Dilution Effects

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    Tsal, Yehoshua; Benoni, Hanna

    2010-01-01

    The substantial distractor interference obtained for small displays when the target appears alone is reduced in large displays when the target is embedded among neutral letters. This finding has been interpreted as reflecting low-load and high-load processing, respectively, thereby supporting the theory of perceptual load (Lavie & Tsal, 1994).…

  12. Enhancement and suppression in the visual field under perceptual load.

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    Parks, Nathan A; Beck, Diane M; Kramer, Arthur F

    2013-01-01

    The perceptual load theory of attention proposes that the degree to which visual distractors are processed is a function of the attentional demands of a task-greater demands increase filtering of irrelevant distractors. The spatial configuration of such filtering is unknown. Here, we used steady-state visual evoked potentials (SSVEPs) in conjunction with time-domain event-related potentials (ERPs) to investigate the distribution of load-induced distractor suppression and task-relevant enhancement in the visual field. Electroencephalogram (EEG) was recorded while subjects performed a foveal go/no-go task that varied in perceptual load. Load-dependent distractor suppression was assessed by presenting a contrast reversing ring at one of three eccentricities (2, 6, or 11°) during performance of the go/no-go task. Rings contrast reversed at 8.3 Hz, allowing load-dependent changes in distractor processing to be tracked in the frequency-domain. ERPs were calculated to the onset of stimuli in the load task to examine load-dependent modulation of task-relevant processing. Results showed that the amplitude of the distractor SSVEP (8.3 Hz) was attenuated under high perceptual load (relative to low load) at the most proximal (2°) eccentricity but not at more eccentric locations (6 or 11°). Task-relevant ERPs revealed a significant increase in N1 amplitude under high load. These results are consistent with a center-surround configuration of load-induced enhancement and suppression in the visual field.

  13. Perceptual load modifies processing of unattended stimuli both in the presence and absence of attended stimuli.

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    Couperus, J W

    2010-11-26

    This study explored effects of perceptual load on stimulus processing in the presence and absence of an attended stimulus. Participants were presented with a bilateral or unilateral display and asked to perform a discrimination task at either low or high perceptual load. Electrophysiological responses to stimuli were then compared at the P100 and N100. As in previous studies, perceptual load modified processing of attended and unattended stimuli seen at occipital scalp sites. Moreover, perceptual load modulated attention effects when the attended stimulus was presented at high perceptual load for unilateral displays. However, this was not true when the attended and unattended stimulus appeared simultaneously in bilateral displays. Instead, only a main effect of perceptual load was found. Reductions in processing contralateral to the unattended stimulus at the N100 provide support for Lavie's (1995) theory of selective attention. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  14. Enhancement and Suppression in the Visual Field under Perceptual Load

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    Nathan A Parks

    2013-05-01

    Full Text Available The perceptual load theory of attention proposes that the degree to which visual distractors are processed is a function of the attentional demands of a task – greater demands increase filtering of irrelevant distractors. The spatial configuration of such filtering is unknown. Here, we used steady-state visual evoked potentials (SSVEPs in conjunction with time-domain event-related potentials (ERPs to investigate the distribution of load-induced distractor suppression and task-relevant enhancement in the visual field. Electroencephalogram (EEG was recorded while subjects performed a foveal go/no-go task that varied in perceptual load. Load-dependent distractor suppression was assessed by presenting a contrast reversing ring at one of three eccentricities (2°, 6°, or 11° during performance of the go/no-go task. Rings contrast reversed at 8.3 Hz, allowing load-dependent changes in distractor processing to be tracked in the frequency-domain. ERPs were calculated to the onset of stimuli in the load task to examine load-dependent modulation of task-relevant processing. Results showed that the amplitude of the distractor SSVEP (8.3Hz was attenuated under high perceptual load (relative to low load at the most proximal (2° eccentricity but not at more eccentric locations (6˚ or 11˚. Task-relevant ERPs revealed a significant increase in N1 amplitude under high load. These results are consistent with a center-surround configuration of load-induced enhancement and suppression in the visual field.

  15. Blinded by the load: attention, awareness and the role of perceptual load.

    Science.gov (United States)

    Lavie, Nilli; Beck, Diane M; Konstantinou, Nikos

    2014-05-05

    What is the relationship between attention and conscious awareness? Awareness sometimes appears to be restricted to the contents of focused attention, yet at other times irrelevant distractors will dominate awareness. This contradictory relationship has also been reflected in an abundance of discrepant research findings leading to an enduring controversy in cognitive psychology. Lavie's load theory of attention suggests that the puzzle can be solved by considering the role of perceptual load. Although distractors will intrude upon awareness in conditions of low load, awareness will be restricted to the content of focused attention when the attended information involves high perceptual load. Here, we review recent evidence for this proposal with an emphasis on the various subjective blindness phenomena, and their neural correlates, induced by conditions of high perceptual load. We also present novel findings that clarify the role of attention in the response to stimulus contrast. Overall, this article demonstrates a critical role for perceptual load across the spectrum of perceptual processes leading to awareness, from the very early sensory responses related to contrast detection to explicit recognition of semantic content.

  16. Low level perceptual, not attentional, processes modulate distractor interference in high perceptual load displays: evidence from neglect/extinction.

    Science.gov (United States)

    Mevorach, Carmel; Tsal, Yehoshua; Humphreys, Glyn W

    2014-01-10

    According to perceptual load theory (Lavie, 2005) distractor interference is determined by the availability of attentional resources. If target processing does not exhaust resources (with low perceptual load) distractor processing will take place resulting in interference with a primary task; however, when target processing uses-up attentional capacity (with high perceptual load) interference can be avoided. An alternative account (Tsal and Benoni, 2010a) suggests that perceptual load effects can be based on distractor dilution by the mere presence of additional neutral items in high-load displays so that the effect is not driven by the amount of attention resources required for target processing. Here we tested whether patients with unilateral neglect or extinction would show dilution effects from neutral items in their contralesional (neglected/extinguished) field, even though these items do not impose increased perceptual load on the target and at the same time attract reduced attentional resources compared to stimuli in the ipsilesional field. Thus, such items do not affect the amount of attention resources available for distractor processing. We found that contralesional neutral elements can eliminate distractor interference as strongly as centrally presented ones in neglect/extinction patients, despite contralesional items being less well attended. The data are consistent with an account in terms of perceptual dilution of distracters rather than available resources for distractor processing. We conclude that distractor dilution can underlie the elimination of distractor interference in visual displays.

  17. Low level perceptual, not attentional, processes modulate distractor interference in high perceptual Load displays: evidence from neglect/extinction

    Directory of Open Access Journals (Sweden)

    Carmel eMevorach

    2014-01-01

    Full Text Available According to perceptual load theory (Lavie, 2005 distractor interference is determined by the availability of attentional resources. If target processing does not exhaust resources (with low perceptual load distractor processing will take place resulting in interference with a primary task; however when target processing uses-up attentional capacity (with high perceptual load interference can be avoided. An alternative account (Tsal & Benoni, 2010 suggests that perceptual load effects can be based on distractor dilution by the mere presence of additional neutral items in high load displays so that the effect is not driven by the amount of attention resources required for target processing. Here we tested whether patients with unilateral neglect or extinction would show dilution effects from neutral items in their contralesional (neglected/extinguished field, even though these items do not impose increased perceptual load on the target and at the same time attract reduced attentional resources compared to stimuli in the ipsilesional field. Thus, such items do not affect the amount of attention resources available for distractor processing. We found that contralesional neutral elements can eliminate distractor interference as strongly as centrally presented ones in neglect/extinction patients, despite contralesional items being less well attended. The data are consistent with an account in terms of perceptual dilution of distracters rather than available resources for distractor processing. We conclude that distractor dilution can underlie the elimination of distractor interference in visual displays.

  18. Multisensory Cues Capture Spatial Attention Regardless of Perceptual Load

    Science.gov (United States)

    Santangelo, Valerio; Spence, Charles

    2007-01-01

    We compared the ability of auditory, visual, and audiovisual (bimodal) exogenous cues to capture visuo-spatial attention under conditions of no load versus high perceptual load. Participants had to discriminate the elevation (up vs. down) of visual targets preceded by either unimodal or bimodal cues under conditions of high perceptual load (in…

  19. Blinded by the load: attention, awareness and the role of perceptual load

    OpenAIRE

    Lavie, Nilli; Beck, Diane M.; Konstantinou, Nikos

    2014-01-01

    What is the relationship between attention and conscious awareness? Awareness sometimes appears to be restricted to the contents of focused attention, yet at other times irrelevant distractors will dominate awareness. This contradictory relationship has also been reflected in an abundance of discrepant research findings leading to an enduring controversy in cognitive psychology. Lavie's load theory of attention suggests that the puzzle can be solved by considering the role of perceptual load....

  20. Blinded by the load: attention, awareness and the role of perceptual load.

    OpenAIRE

    Lavie, N.; Beck, D. M.; Konstantinou, N.

    2014-01-01

    What is the relationship between attention and conscious awareness? Awareness sometimes appears to be restricted to the contents of focused attention, yet at other times irrelevant distractors will dominate awareness. This contradictory relationship has also been reflected in an abundance of discrepant research findings leading to an enduring controversy in cognitive psychology. Lavie's load theory of attention suggests that the puzzle can be solved by considering the role of perceptual load....

  1. The influence of schizotypal traits on attention under high perceptual load.

    Science.gov (United States)

    Stotesbury, Hanne; Gaigg, Sebastian B; Kirhan, Saim; Haenschel, Corinna

    2018-03-01

    Schizophrenia Spectrum Disorders (SSD) are known to be characterised by abnormalities in attentional processes, but there are inconsistencies in the literature that remain unresolved. This article considers whether perceptual resource limitations play a role in moderating attentional abnormalities in SSD. According to perceptual load theory, perceptual resource limitations can lead to attenuated or superior performance on dual-task paradigms depending on whether participants are required to process, or attempt to ignore, secondary stimuli. If SSD is associated with perceptual resource limitations, and if it represents the extreme end of an otherwise normally distributed neuropsychological phenotype, schizotypal traits in the general population should lead to disproportionate performance costs on dual-task paradigms as a function of the perceptual task demands. To test this prediction, schizotypal traits were quantified via the Schizotypal Personality Questionnaire (SPQ) in 74 healthy volunteers, who also completed a dual-task signal detection paradigm that required participants to detect central and peripheral stimuli across conditions that varied in the overall number of stimuli presented. The results confirmed decreasing performance as the perceptual load of the task increased. More importantly, significant correlations between SPQ scores and task performance confirmed that increased schizotypal traits, particularly in the cognitive-perceptual domain, are associated with greater performance decrements under increasing perceptual load. These results confirm that attentional difficulties associated with SSD extend sub-clinically into the general population and suggest that cognitive-perceptual schizotypal traits may represent a risk factor for difficulties in the regulation of attention under increasing perceptual load.

  2. Stimulus recognition occurs under high perceptual load: Evidence from correlated flankers.

    Science.gov (United States)

    Cosman, Joshua D; Mordkoff, J Toby; Vecera, Shaun P

    2016-12-01

    A dominant account of selective attention, perceptual load theory, proposes that when attentional resources are exhausted, task-irrelevant information receives little attention and goes unrecognized. However, the flanker effect-typically used to assay stimulus identification-requires an arbitrary mapping between a stimulus and a response. We looked for failures of flanker identification by using a more-sensitive measure that does not require arbitrary stimulus-response mappings: the correlated flankers effect. We found that flanking items that were task-irrelevant but that correlated with target identity produced a correlated flanker effect. Participants were faster on trials in which the irrelevant flanker had previously correlated with the target than when it did not. Of importance, this correlated flanker effect appeared regardless of perceptual load, occurring even in high-load displays that should have abolished flanker identification. Findings from a standard flanker task replicated the basic perceptual load effect, with flankers not affecting response times under high perceptual load. Our results indicate that task-irrelevant information can be processed to a high level (identification), even under high perceptual load. This challenges a strong account of high perceptual load effects that hypothesizes complete failures of stimulus identification under high perceptual load. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  3. The Competitive Influences of Perceptual Load and Working Memory Guidance on Selective Attention.

    Directory of Open Access Journals (Sweden)

    Jinfeng Tan

    Full Text Available The perceptual load theory in selective attention literature proposes that the interference from task-irrelevant distractor is eliminated when perceptual capacity is fully consumed by task-relevant information. However, the biased competition model suggests that the contents of working memory (WM can guide attentional selection automatically, even when this guidance is detrimental to visual search. An intriguing but unsolved question is what will happen when selective attention is influenced by both perceptual load and WM guidance. To study this issue, behavioral performances and event-related potentials (ERPs were recorded when participants were presented with a cue to either identify or hold in memory and had to perform a visual search task subsequently, under conditions of low or high perceptual load. Behavioural data showed that high perceptual load eliminated the attentional capture by WM. The ERP results revealed an obvious WM guidance effect in P1 component with invalid trials eliciting larger P1 than neutral trials, regardless of the level of perceptual load. The interaction between perceptual load and WM guidance was significant for the posterior N1 component. The memory guidance effect on N1 was eliminated by high perceptual load. Standardized Low Resolution Electrical Tomography Analysis (sLORETA showed that the WM guidance effect and the perceptual load effect on attention can be localized into the occipital area and parietal lobe, respectively. Merely identifying the cue produced no effect on the P1 or N1 component. These results suggest that in selective attention, the information held in WM could capture attention at the early stage of visual processing in the occipital cortex. Interestingly, this initial capture of attention by WM could be modulated by the level of perceptual load and the parietal lobe mediates target selection at the discrimination stage.

  4. The Competitive Influences of Perceptual Load and Working Memory Guidance on Selective Attention.

    Science.gov (United States)

    Tan, Jinfeng; Zhao, Yuanfang; Wang, Lijun; Tian, Xia; Cui, Yan; Yang, Qian; Pan, Weigang; Zhao, Xiaoyue; Chen, Antao

    2015-01-01

    The perceptual load theory in selective attention literature proposes that the interference from task-irrelevant distractor is eliminated when perceptual capacity is fully consumed by task-relevant information. However, the biased competition model suggests that the contents of working memory (WM) can guide attentional selection automatically, even when this guidance is detrimental to visual search. An intriguing but unsolved question is what will happen when selective attention is influenced by both perceptual load and WM guidance. To study this issue, behavioral performances and event-related potentials (ERPs) were recorded when participants were presented with a cue to either identify or hold in memory and had to perform a visual search task subsequently, under conditions of low or high perceptual load. Behavioural data showed that high perceptual load eliminated the attentional capture by WM. The ERP results revealed an obvious WM guidance effect in P1 component with invalid trials eliciting larger P1 than neutral trials, regardless of the level of perceptual load. The interaction between perceptual load and WM guidance was significant for the posterior N1 component. The memory guidance effect on N1 was eliminated by high perceptual load. Standardized Low Resolution Electrical Tomography Analysis (sLORETA) showed that the WM guidance effect and the perceptual load effect on attention can be localized into the occipital area and parietal lobe, respectively. Merely identifying the cue produced no effect on the P1 or N1 component. These results suggest that in selective attention, the information held in WM could capture attention at the early stage of visual processing in the occipital cortex. Interestingly, this initial capture of attention by WM could be modulated by the level of perceptual load and the parietal lobe mediates target selection at the discrimination stage.

  5. Steady-state signatures of visual perceptual load, multimodal distractor filtering, and neural competition.

    Science.gov (United States)

    Parks, Nathan A; Hilimire, Matthew R; Corballis, Paul M

    2011-05-01

    The perceptual load theory of attention posits that attentional selection occurs early in processing when a task is perceptually demanding but occurs late in processing otherwise. We used a frequency-tagged steady-state evoked potential paradigm to investigate the modality specificity of perceptual load-induced distractor filtering and the nature of neural-competitive interactions between task and distractor stimuli. EEG data were recorded while participants monitored a stream of stimuli occurring in rapid serial visual presentation (RSVP) for the appearance of previously assigned targets. Perceptual load was manipulated by assigning targets that were identifiable by color alone (low load) or by the conjunction of color and orientation (high load). The RSVP task was performed alone and in the presence of task-irrelevant visual and auditory distractors. The RSVP stimuli, visual distractors, and auditory distractors were "tagged" by modulating each at a unique frequency (2.5, 8.5, and 40.0 Hz, respectively), which allowed each to be analyzed separately in the frequency domain. We report three important findings regarding the neural mechanisms of perceptual load. First, we replicated previous findings of within-modality distractor filtering and demonstrated a reduction in visual distractor signals with high perceptual load. Second, auditory steady-state distractor signals were unaffected by manipulations of visual perceptual load, consistent with the idea that perceptual load-induced distractor filtering is modality specific. Third, analysis of task-related signals revealed that visual distractors competed with task stimuli for representation and that increased perceptual load appeared to resolve this competition in favor of the task stimulus.

  6. Individual differences at high perceptual load: the relation between trait anxiety and selective attention.

    Science.gov (United States)

    Sadeh, Naomi; Bredemeier, Keith

    2011-06-01

    Attentional control theory (Eysenck et al., 2007) posits that taxing attentional resources impairs performance efficiency in anxious individuals. This theory, however, does not explicitly address if or how the relation between anxiety and attentional control depends upon the perceptual demands of the task at hand. Consequently, the present study examined the relation between trait anxiety and task performance using a perceptual load task (Maylor & Lavie, 1998). Sixty-eight male college students completed a visual search task that indexed processing of irrelevant distractors systematically across four levels of perceptual load. Results indicated that anxiety was related to difficulty suppressing the behavioural effects of irrelevant distractors (i.e., decreased reaction time efficiency) under high, but not low, perceptual loads. In contrast, anxiety was not associated with error rates on the task. These findings are consistent with the prediction that anxiety is associated with impairments in performance efficiency under conditions that tax attentional resources.

  7. Face and object encoding under perceptual load: ERP evidence.

    Science.gov (United States)

    Neumann, Markus F; Mohamed, Tarik N; Schweinberger, Stefan R

    2011-02-14

    According to the perceptual load theory, processing of a task-irrelevant distractor is abolished when attentional resources are fully consumed by task-relevant material. As an exception, however, famous faces have been shown to elicit repetition modulations in event-related potentials - an N250r - despite high load at initial presentation, suggesting preserved face-encoding. Here, we recorded N250r repetition modulations by unfamiliar faces, hands, and houses, and tested face specificity of preserved encoding under high load. In an immediate (S1-S2) repetition priming paradigm, participants performed a letter identification task on S1 by indicating whether an "X" vs. "N" was among 6 different (high load condition) or 6 identical (low load condition) letters. Letter strings were superimposed on distractor faces, hands, or houses. Subsequent S2 probes were either identical repetitions of S1 distractors, non-repeated exemplars from the same category, or infrequent butterflies, to which participants responded. Independent of attentional load at S1, an occipito-temporal N250r was found for unfamiliar faces. In contrast, no repetition-related neural modulation emerged for houses or hands. This strongly suggests that a putative face-selective attention module supports encoding under high load, and that similar mechanisms are unavailable for other natural or artificial objects. Copyright © 2010 Elsevier Inc. All rights reserved.

  8. The influence of schizotypal traits on attention under high perceptual load

    Directory of Open Access Journals (Sweden)

    Hanne Stotesbury

    2018-03-01

    Full Text Available Schizophrenia Spectrum Disorders (SSD are known to be characterised by abnormalities in attentional processes, but there are inconsistencies in the literature that remain unresolved. This article considers whether perceptual resource limitations play a role in moderating attentional abnormalities in SSD. According to perceptual load theory, perceptual resource limitations can lead to attenuated or superior performance on dual-task paradigms depending on whether participants are required to process, or attempt to ignore, secondary stimuli. If SSD is associated with perceptual resource limitations, and if it represents the extreme end of an otherwise normally distributed neuropsychological phenotype, schizotypal traits in the general population should lead to disproportionate performance costs on dual-task paradigms as a function of the perceptual task demands. To test this prediction, schizotypal traits were quantified via the Schizotypal Personality Questionnaire (SPQ in 74 healthy volunteers, who also completed a dual-task signal detection paradigm that required participants to detect central and peripheral stimuli across conditions that varied in the overall number of stimuli presented. The results confirmed decreasing performance as the perceptual load of the task increased. More importantly, significant correlations between SPQ scores and task performance confirmed that increased schizotypal traits, particularly in the cognitive-perceptual domain, are associated with greater performance decrements under increasing perceptual load. These results confirm that attentional difficulties associated with SSD extend sub-clinically into the general population and suggest that cognitive-perceptual schizotypal traits may represent a risk factor for difficulties in the regulation of attention under increasing perceptual load.

  9. A new perspective on the perceptual selectivity of attention under load

    DEFF Research Database (Denmark)

    Giesbrecht, Barry; Sy, Jocelyn; Bundesen, Claus

    2014-01-01

    The human attention system helps us cope with a complex environment by supporting the selective processing of information relevant to our current goals. Understanding the perceptual, cognitive, and neural mechanisms that mediate selective attention is a core issue in cognitive neuroscience. One...... prominent model of selective attention, known as load theory, offers an account of how task demands determine when information is selected and an account of the efficiency of the selection process. However, load theory has several critical weaknesses that suggest that it is time for a new perspective. Here...... is integrated to provide efficient attentional selection and allocation of perceptual processing resources....

  10. Where have we gone wrong? Perceptual load does not affect selective attention.

    Science.gov (United States)

    Benoni, Hanna; Tsal, Yehoshua

    2010-06-18

    The theory of perceptual load (Lavie & Tsal, 1994) proposes that with low load in relevant processing left over resources spill over to process irrelevant distractors. Interference could only be prevented under High-Load Conditions where relevant processing exhausts attentional resources. The theory is based primarily on the finding that distractor interference obtained in low load displays, when the target appears alone, is eliminated in high load displays when it is embedded among neutral letters. However, a possible alternative interpretation of this effect is that the distractor is similarly processed in both displays, yet its interference in the large displays is diluted by the presence of the neutral letters. We separated the possible effects of load and dilution by adding dilution displays that were high in dilution and low in perceptual load. In the first experiment these displays contained as many letters as the high load displays, but their neutral letters were clearly distinguished from the target, thereby allowing for a low load processing mode. In the second experiment we presented identical multicolor displays in the Dilution and High-Load Conditions. However, in the former the target color was known in advance (thereby preserving a low load processing mode) whereas in the latter it was not. In both experiments distractor interference was completely eliminated under the Dilution Condition. Thus, it is dilution not perceptual load affecting distractor processing. 2010 Elsevier Ltd. All rights reserved.

  11. Is Hand Selection Modulated by Cognitive-perceptual Load?

    Science.gov (United States)

    Liang, Jiali; Wilkinson, Krista; Sainburg, Robert L

    2018-01-15

    Previous studies proposed that selecting which hand to use for a reaching task appears to be modulated by a factor described as "task difficulty". However, what features of a task might contribute to greater or lesser "difficulty" in the context of hand selection decisions has yet to be determined. There has been evidence that biomechanical and kinematic factors such as movement smoothness and work can predict patterns of selection across the workspace, suggesting a role of predictive cost analysis in hand-selection. We hypothesize that this type of prediction for hand-selection should recruit substantial cognitive resources and thus should be influenced by cognitive-perceptual loading. We test this hypothesis by assessing the role of cognitive-perceptual loading on hand selection decisions, using a visual search task that presents different levels of difficulty (cognitive-perceptual load), as established in previous studies on overall response time and efficiency of visual search. Although the data are necessarily preliminary due to small sample size, our data suggested an influence of cognitive-perceptual load on hand selection, such that the dominant hand was selected more frequently as cognitive load increased. Interestingly, cognitive-perceptual loading also increased cross-midline reaches with both hands. Because crossing midline is more costly in terms of kinematic and kinetic factors, our findings suggest that cognitive processes are normally engaged to avoid costly actions, and that the choice not-to-cross midline requires cognitive resources. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  12. The fate of task-irrelevant visual motion: perceptual load versus feature-based attention.

    Science.gov (United States)

    Taya, Shuichiro; Adams, Wendy J; Graf, Erich W; Lavie, Nilli

    2009-11-18

    We tested contrasting predictions derived from perceptual load theory and from recent feature-based selection accounts. Observers viewed moving, colored stimuli and performed low or high load tasks associated with one stimulus feature, either color or motion. The resultant motion aftereffect (MAE) was used to evaluate attentional allocation. We found that task-irrelevant visual features received less attention than co-localized task-relevant features of the same objects. Moreover, when color and motion features were co-localized yet perceived to belong to two distinct surfaces, feature-based selection was further increased at the expense of object-based co-selection. Load theory predicts that the MAE for task-irrelevant motion would be reduced with a higher load color task. However, this was not seen for co-localized features; perceptual load only modulated the MAE for task-irrelevant motion when this was spatially separated from the attended color location. Our results suggest that perceptual load effects are mediated by spatial selection and do not generalize to the feature domain. Feature-based selection operates to suppress processing of task-irrelevant, co-localized features, irrespective of perceptual load.

  13. A new perspective on the perceptual selectivity of attention under load.

    Science.gov (United States)

    Giesbrecht, Barry; Sy, Jocelyn; Bundesen, Claus; Kyllingsbaek, Søren

    2014-05-01

    The human attention system helps us cope with a complex environment by supporting the selective processing of information relevant to our current goals. Understanding the perceptual, cognitive, and neural mechanisms that mediate selective attention is a core issue in cognitive neuroscience. One prominent model of selective attention, known as load theory, offers an account of how task demands determine when information is selected and an account of the efficiency of the selection process. However, load theory has several critical weaknesses that suggest that it is time for a new perspective. Here we review the strengths and weaknesses of load theory and offer an alternative biologically plausible computational account that is based on the neural theory of visual attention. We argue that this new perspective provides a detailed computational account of how bottom-up and top-down information is integrated to provide efficient attentional selection and allocation of perceptual processing resources. © 2014 New York Academy of Sciences.

  14. Load Theory of Selective Attention and Cognitive Control

    Science.gov (United States)

    Lavie, Nilli; Hirst, Aleksandra; de Fockert, Jan W.; Viding, Essi

    2004-01-01

    A load theory of attention in which distractor rejection depends on the level and type of load involved in current processing was tested. A series of experiments demonstrates that whereas high perceptual load reduces distractor interference, working memory load or dual-task coordination load increases distractor interference. These findings…

  15. Perceptual and Cognitive Load Interact to Control the Spatial Focus of Attention

    Science.gov (United States)

    Linnell, Karina J.; Caparos, Serge

    2011-01-01

    Caparos and Linnell (2009, 2010) used a variable-separation flanker paradigm to show that (a) when cognitive load is low, increasing perceptual load causes spatial attention to focus and (b) when perceptual load is high, decreasing cognitive load causes spatial attention to focus. Here, we tested whether the effects of perceptual and cognitive…

  16. Cognitive load effects on early visual perceptual processing.

    Science.gov (United States)

    Liu, Ping; Forte, Jason; Sewell, David; Carter, Olivia

    2018-05-01

    Contrast-based early visual processing has largely been considered to involve autonomous processes that do not need the support of cognitive resources. However, as spatial attention is known to modulate early visual perceptual processing, we explored whether cognitive load could similarly impact contrast-based perception. We used a dual-task paradigm to assess the impact of a concurrent working memory task on the performance of three different early visual tasks. The results from Experiment 1 suggest that cognitive load can modulate early visual processing. No effects of cognitive load were seen in Experiments 2 or 3. Together, the findings provide evidence that under some circumstances cognitive load effects can penetrate the early stages of visual processing and that higher cognitive function and early perceptual processing may not be as independent as was once thought.

  17. Plugging the attention deficit: perceptual load counters increased distraction in ADHD.

    Science.gov (United States)

    Forster, Sophie; Robertson, David J; Jennings, Alistair; Asherson, Philip; Lavie, Nilli

    2014-01-01

    Increased vulnerability to extraneous distraction is a key symptom of Attention-Deficit Hyperactivity Disorder (ADHD), which may have particularly disruptive consequences. Here we apply Load Theory of attention to increase understanding of this symptom, and to explore a potential method for ameliorating it. Previous research in nonclinical populations has highlighted increased perceptual load as a means of improving the ability to focus attention and avoid distraction. The present study examines whether adults with ADHD can also benefit from conditions of high perceptual load to improve their focused attention abilities. We tested adults with ADHD and age- and IQ-matched controls on a novel measure of irrelevant distraction under load, designed to parallel the form of distraction that is symptomatic of ADHD. During a letter search task, in which perceptual load was varied through search set size, participants were required to ignore salient yet entirely irrelevant distractors (colorful images of cartoon characters) presented infrequently (10% of trials). The presence of these distractors produced a significantly greater interference effect on the search RTs for the adults with ADHD compared with controls, p = .005, ηp² = .231. Perceptual load, however, significantly reduced distractor interference for the ADHD group and was as effective in reducing the elevated distractor interference in ADHD as it was for controls. These findings clarify the nature of the attention deficit underlying increased distraction in ADHD, and demonstrate a tangible method for overcoming it.

  18. Cognitive load theory

    NARCIS (Netherlands)

    Kirschner, Paul A.; Kirschner, Femke; Paas, Fred

    2010-01-01

    Kirschner, P. A., Kirschner, F. C., & Paas, F. (2009). Cognitive load theory. In E. M. Anderman & L. H. Anderman (Eds.). Psychology of classroom learning: An encyclopedia, Volume 1, a-j (pp. 205-209). Detroit, MI: Macmillan Reference.

  19. Processing of unattended, simple negative pictures resists perceptual load.

    Science.gov (United States)

    Sand, Anders; Wiens, Stefan

    2011-05-11

    As researchers debate whether emotional pictures can be processed irrespective of spatial attention and perceptual load, negative and neutral pictures of simple figure-ground composition were shown at fixation and were surrounded by one, two, or three letters. When participants performed a picture discrimination task, there was evidence for motivated attention; that is, an early posterior negativity (EPN) and late positive potential (LPP) to negative versus neutral pictures. When participants performed a letter discrimination task, the EPN was unaffected whereas the LPP was reduced. Although performance decreased substantially with the number of letters (one to three), the LPP did not decrease further. Therefore, attention to simple, negative pictures at fixation seems to resist manipulations of perceptual load.

  20. I can see clearly now: The effects of age and perceptual load on inattentional blindness

    Directory of Open Access Journals (Sweden)

    Anna eRemington

    2014-04-01

    Full Text Available Attention and awareness are known to be linked (e.g. see Lavie, Beck, & Konstantinou, 2014, for a review. However the extent to which this link changes over development is not fully understood. Most research concerning the development of attention has investigated the effects of attention on distraction, visual search and spatial orienting, typically using reaction time measures which cannot directly support conclusions about conscious awareness. Here we used Lavie’s Load Theory of Attention and Cognitive Control to examine the development of attention effects on awareness. According to Load Theory awareness levels are determined by the availability of attentional capacity. We hypothesised that attentional capacity develops with age, and consequently that awareness rates should increase with development due to the enhanced capacity. Thus we predicted that greater rates of inattentional blindness (IB would be found at a younger age, and that lower levels of perceptual load will be sufficient to exhaust capacity and cause IB in children but not adults. We tested this hypothesis using an IB paradigm with adults and children aged 7-8, 9-10, 11-12 and 13 years old. Participants performed a line-length judgment task (indicating which arm of a cross is longer and on the last trial were asked to report whether they noticed an unexpected task-irrelevant stimulus (a small square in the display. Perceptual load was varied by changing the line-length difference (with a smaller difference in the conditions of higher load. The results supported our hypothesis: levels of awareness increased with age, and a moderate increase in the perceptual load of the task led to greater IB for children but not adults. These results extended across both peripheral and central presentations of the task stimuli. Overall, these findings establish the development of capacity for awareness and demonstrate the critical role of the perceptual load in the attended task.

  1. Beyond perceptual load and dilution: a review of the role of working memory in selective attention

    Science.gov (United States)

    de Fockert, Jan W.

    2013-01-01

    The perceptual load and dilution models differ fundamentally in terms of the proposed mechanism underlying variation in distractibility during different perceptual conditions. However, both models predict that distracting information can be processed beyond perceptual processing under certain conditions, a prediction that is well-supported by the literature. Load theory proposes that in such cases, where perceptual task aspects do not allow for sufficient attentional selectivity, the maintenance of task-relevant processing depends on cognitive control mechanisms, including working memory. The key prediction is that working memory plays a role in keeping clear processing priorities in the face of potential distraction, and the evidence reviewed and evaluated in a meta-analysis here supports this claim, by showing that the processing of distracting information tends to be enhanced when load on a concurrent task of working memory is high. Low working memory capacity is similarly associated with greater distractor processing in selective attention, again suggesting that the unavailability of working memory during selective attention leads to an increase in distractibility. Together, these findings suggest that selective attention against distractors that are processed beyond perception depends on the availability of working memory. Possible mechanisms for the effects of working memory on selective attention are discussed. PMID:23734139

  2. Beyond perceptual load and dilution: a review of the role of working memory in selective attention.

    Science.gov (United States)

    de Fockert, Jan W

    2013-01-01

    The perceptual load and dilution models differ fundamentally in terms of the proposed mechanism underlying variation in distractibility during different perceptual conditions. However, both models predict that distracting information can be processed beyond perceptual processing under certain conditions, a prediction that is well-supported by the literature. Load theory proposes that in such cases, where perceptual task aspects do not allow for sufficient attentional selectivity, the maintenance of task-relevant processing depends on cognitive control mechanisms, including working memory. The key prediction is that working memory plays a role in keeping clear processing priorities in the face of potential distraction, and the evidence reviewed and evaluated in a meta-analysis here supports this claim, by showing that the processing of distracting information tends to be enhanced when load on a concurrent task of working memory is high. Low working memory capacity is similarly associated with greater distractor processing in selective attention, again suggesting that the unavailability of working memory during selective attention leads to an increase in distractibility. Together, these findings suggest that selective attention against distractors that are processed beyond perception depends on the availability of working memory. Possible mechanisms for the effects of working memory on selective attention are discussed.

  3. Beyond perceptual load and dilution: a review of the role of working memory in selective attention

    Directory of Open Access Journals (Sweden)

    Jan W. De Fockert

    2013-05-01

    Full Text Available The perceptual load and dilution models differ fundamentally in terms of the proposed mechanism underlying variation in distractibility during different perceptual conditions. However, both models predict that distracting information can be processed beyond perceptual processing under certain conditions, a prediction that is well-supported by the literature. Load theory proposes that in such cases, where perceptual task aspects do not allow for sufficient attentional selectivity, the maintenance of task-relevant processing depends on cognitive control mechanisms, including working memory. The key prediction is that working memory plays a role in keeping clear processing priorities in the face of potential distraction, and the evidence reviewed and evaluated in a meta-analysis here supports this claim, by showing that the processing of distracting information tends to be enhanced when load on a concurrent task of working memory is high. Low working memory capacity is similarly associated with greater distractor processing in selective attention, again suggesting that the unavailability of working memory during selective attention leads to an increase in distractibility. Together, these findings suggest that selective attention against distractors that are processed beyond perception depends on the availability of working memory. Possible mechanisms for the effects of working memory on selective attention are discussed.

  4. Zooming in on the cause of the perceptual load effect in the go/no-go paradigm.

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    Chen, Zhe; Cave, Kyle R

    2016-08-01

    Perceptual load theory (Lavie, 2005) claims that attentional capacity that is not used for the current task is allocated to irrelevant distractors. It predicts that if the attentional demands of the current task are high, distractor interference will be low. One particularly powerful demonstration of perceptual load effects on distractor processing relies on a go/no-go cue that is interpreted by either simple feature detection or feature conjunction (Lavie, 1995). However, a possible alternative interpretation of these effects is that the differential degree of distractor processing is caused by how broadly attention is allocated (attentional zoom) rather than to perceptual load. In 4 experiments, we show that when stimuli are arranged to equalize the extent of spatial attention across conditions, distractor interference varies little whether cues are defined by a simple feature or a conjunction, and that the typical perceptual load effect emerges only when attentional zoom can covary with perceptual load. These results suggest that attentional zoom can account for the differential degree of distractor processing traditionally attributed to perceptual load in the go/no-go paradigm. They also provide new insight into how different factors interact to control distractor interference. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  5. Can we "apply" the findings of Forster and Lavie (2008)? On the generalizability of attentional capture effects under varying levels of perceptual load.

    Science.gov (United States)

    Lleras, Alejandro; Chu, Hengqing; Buetti, Simona

    2017-06-01

    Perceptual Load theory states that the degree of perceptual load on a display determines the amount of leftover attentional resources that the system can use to process distracting information. An important corollary of this theory is that the amount of perceptual load determines the vulnerability of the attention system to being captured by completely irrelevant stimuli, predicting larger amounts of capture with low perceptual load than with high perceptual load. This prediction was first confirmed by Forster and Lavie (2008). Here, we report 6 experiments that followed up on those earlier results, where we find that in many cases, the opposite pattern is obtained: attentional capture increased with increasing perceptual load. Given the lack of generalizability of the theory to new experimental contexts with fairly minor methodological differences, we conclude that Perceptual Load may not be a useful framework for understanding attentional capture. The theoretical and applied importance of these findings is discussed. In particular, we caution against using this theory in applied tasks and settings because best-use recommendations stemming from this theory regarding strategies to decrease distractibility may in fact produce the opposite effect: an increase in distractibility (with distractibility being indexed by the magnitude of the capture effect). (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  6. I can see clearly now: the effects of age and perceptual load on inattentional blindness.

    Science.gov (United States)

    Remington, Anna; Cartwright-Finch, Ula; Lavie, Nilli

    2014-01-01

    Attention and awareness are known to be linked (e.g., see Lavie et al., 2014, for a review). However the extent to which this link changes over development is not fully understood. Most research concerning the development of attention has investigated the effects of attention on distraction, visual search and spatial orienting, typically using reaction time measures which cannot directly support conclusions about conscious awareness. Here we used Lavie's Load Theory of Attention and Cognitive Control to examine the development of attention effects on awareness. According to Load Theory, awareness levels are determined by the availability of attentional capacity. We hypothesized that attentional capacity develops with age, and consequently that awareness rates should increase with development due to the enhanced capacity. Thus we predicted that greater rates of inattentional blindness (IB) would be found at a younger age, and that lower levels of load will be sufficient to exhaust capacity and cause IB in children but not adults. We tested this hypothesis using an IB paradigm with adults and children aged 7-8, 9-10, 11-12 and 13 years old. Participants performed a line-length judgment task (indicating which arm of a cross is longer) and on the last trial were asked to report whether they noticed an unexpected task-irrelevant stimulus (a small square) in the display. Perceptual load was varied by changing the line-length difference (with a smaller difference in the conditions of higher load). The results supported our hypothesis: levels of awareness increased with age, and a moderate increase in the perceptual load of the task led to greater IB for children but not adults. These results extended across both peripheral and central presentations of the task stimuli. Overall, these findings establish the development of capacity for awareness and demonstrate the critical role of the perceptual load in the attended task.

  7. Perceptual load manipulation reveals sensitivity of the face-selective N170 to attention.

    Science.gov (United States)

    Mohamed, Tarik N; Neumann, Markus F; Schweinberger, Stefan R

    2009-05-27

    It has been controversial whether the face-sensitive N170 is affected by selective attention. We manipulated attention sensu Lavie's perceptual load theory to short (200 ms) presentations of task-irrelevant unfamiliar faces or houses, while participants identified superimposed target letters 'X' versus 'N'. These targets were strings of either six identical (low load) or six different letters (high load). Under low load, we found a prominent face-selective N170 response. Under high load, however, we not only observed a dramatic reduction of the face N170 but also an unexpected enhancement of the house N170, such that face selectivity was almost completely lost. We conclude that the early stages of face processing indexed by the N170 strongly depend on selective attention.

  8. Perceptual load affects exogenous spatial orienting while working memory load does not.

    Science.gov (United States)

    Santangelo, Valerio; Finoia, Paola; Raffone, Antonino; Belardinelli, Marta Olivetti; Spence, Charles

    2008-01-01

    We examined whether or not increasing visual perceptual load or visual working memory (WM) load would affect the exogenous orienting of visuo-spatial attention, in order to assess whether or not exogenous orienting is genuinely automatic. In Experiment 1, we manipulated visual perceptual load by means of a central morphing shape that in some trials morphed into a particular target shape (a rectangle) that participants had to detect. In Experiment 2, the possibility that the presentation of any changing stimulus at fixation would eliminate exogenous orienting was ruled out, by presenting two alternating letters at fixation. In Experiment 3, we manipulated visual WM load by means of arrays consisting of three (low-load) or five (high-load) randomly located coloured squares. The participants had to remember these items in order to judge whether a cued square had been presented in the same or different colour at the end of each trial. In all the experiments, exogenous visuo-spatial attentional orienting was measured by means of an orthogonal spatial cuing task, in which the participants had to discriminate the elevation (up vs. down) of a visual target previously cued by a spatially nonpredictive visual cue. The results showed that increasing the perceptual load of the task eliminated the exogenous orienting of visuo-spatial attention. By contrast, increasing the WM load had no effect on spatial orienting. These results are discussed in terms of the light that they shed on claims regarding the automaticity of visuo-spatial exogenous orienting.

  9. Age-Related Changes in Selective Attention and Perceptual Load During Visual Search

    OpenAIRE

    Madden, David J.; Langley, Linda K.

    2003-01-01

    Three visual search experiments were conducted to test the hypothesis that age differences in selective attention vary as a function of perceptual load (E. A. Maylor & N. Lavie, 1998). Under resource-limited conditions (Experiments 1 and 2), the distraction from irrelevant display items generally decreased as display size (perceptual load) increased. This perceptual load effect was similar for younger and older adults, contrary to the findings of Maylor and Lavie. Distraction at low perceptua...

  10. Perceptual learning: toward a comprehensive theory.

    Science.gov (United States)

    Watanabe, Takeo; Sasaki, Yuka

    2015-01-03

    Visual perceptual learning (VPL) is long-term performance increase resulting from visual perceptual experience. Task-relevant VPL of a feature results from training of a task on the feature relevant to the task. Task-irrelevant VPL arises as a result of exposure to the feature irrelevant to the trained task. At least two serious problems exist. First, there is the controversy over which stage of information processing is changed in association with task-relevant VPL. Second, no model has ever explained both task-relevant and task-irrelevant VPL. Here we propose a dual plasticity model in which feature-based plasticity is a change in a representation of the learned feature, and task-based plasticity is a change in processing of the trained task. Although the two types of plasticity underlie task-relevant VPL, only feature-based plasticity underlies task-irrelevant VPL. This model provides a new comprehensive framework in which apparently contradictory results could be explained.

  11. Perceptual load in different regions of the visual scene and its relevance for driving.

    Science.gov (United States)

    Marciano, Hadas; Yeshurun, Yaffa

    2015-06-01

    The aim of this study was to better understand the role played by perceptual load, at both central and peripheral regions of the visual scene, in driving safety. Attention is a crucial factor in driving safety, and previous laboratory studies suggest that perceptual load is an important factor determining the efficiency of attentional selectivity. Yet, the effects of perceptual load on driving were never studied systematically. Using a driving simulator, we orthogonally manipulated the load levels at the road (central load) and its sides (peripheral load), while occasionally introducing critical events at one of these regions. Perceptual load affected driving performance at both regions of the visual scene. Critically, the effect was different for central versus peripheral load: Whereas load levels on the road mainly affected driving speed, load levels on its sides mainly affected the ability to detect critical events initiating from the roadsides. Moreover, higher levels of peripheral load impaired performance but mainly with low levels of central load, replicating findings with simple letter stimuli. Perceptual load has a considerable effect on driving, but the nature of this effect depends on the region of the visual scene at which the load is introduced. Given the observed importance of perceptual load, authors of future studies of driving safety should take it into account. Specifically, these findings suggest that our understanding of factors that may be relevant for driving safety would benefit from studying these factors under different levels of load at different regions of the visual scene. © 2014, Human Factors and Ergonomics Society.

  12. Modeling the effects of perceptual load: saliency, competitive interactions, and top-down biases.

    Directory of Open Access Journals (Sweden)

    Kleanthis eNeokleous

    2016-01-01

    Full Text Available A computational model of visual selective attention has been implemented to account for experimental findings on the Perceptual Load Theory (PLT of attention. The model was designed based on existing neurophysiological findings on attentional processes with the objective to offer an explicit and biologically plausible formulation of PLT. Simulation results verified that the proposed model is capable of capturing the basic pattern of results that support the Perceptual Load Theory as well as findings that are considered contradictory to the theory. Importantly, the model is able to reproduce the behavioral results from a dilution experiment, providing thus a way to reconcile PLT with the competing Dilution account. Overall, the model presents a novel account for explaining PLT effects on the basis of the low-level competitive interactions among neurons that represent visual input and the top-down signals that modulate neural activity. The implications of the model concerning the debate on the locus of selective attention as well as the origins of distractor interference in visual displays of varying load are discussed.

  13. Social Anxiety Under Load: The Effects of Perceptual Load in Processing Emotional Faces

    Directory of Open Access Journals (Sweden)

    Sandra Cristina Soares

    2015-04-01

    Full Text Available Previous studies in the social anxiety arena have shown an impaired attentional control system, similar to that found in trait anxiety. However, the effect of task demands on social anxiety in socially threatening stimuli, such as angry faces, remains unseen. In the present study, fifty-four university students scoring high and low in the Social Interaction and Performance Anxiety and Avoidance Scale (SIPAAS questionnaire, participated in a target letter discrimination task while task-irrelevant face stimuli (angry, disgust, happy, and neutral were simultaneously presented. The results showed that high (compared to low socially anxious individuals were more prone to distraction by task-irrelevant stimuli, particularly under high perceptual load conditions. More importantly, for such individuals, the accuracy proportions for angry faces significantly differed between the low and high perceptual load conditions, which is discussed in light of current evolutionary models of social anxiety.

  14. Social anxiety under load: the effects of perceptual load in processing emotional faces.

    Science.gov (United States)

    Soares, Sandra C; Rocha, Marta; Neiva, Tiago; Rodrigues, Paulo; Silva, Carlos F

    2015-01-01

    Previous studies in the social anxiety arena have shown an impaired attentional control system, similar to that found in trait anxiety. However, the effect of task demands on social anxiety in socially threatening stimuli, such as angry faces, remains unseen. In the present study, 54 university students scoring high and low in the Social Interaction and Performance Anxiety and Avoidance Scale (SIPAAS) questionnaire, participated in a target letter discrimination task while task-irrelevant face stimuli (angry, disgust, happy, and neutral) were simultaneously presented. The results showed that high (compared to low) socially anxious individuals were more prone to distraction by task-irrelevant stimuli, particularly under high perceptual load conditions. More importantly, for such individuals, the accuracy proportions for angry faces significantly differed between the low and high perceptual load conditions, which is discussed in light of current evolutionary models of social anxiety.

  15. Visual perceptual load reduces auditory detection in typically developing individuals but not in individuals with autism spectrum disorders.

    Science.gov (United States)

    Tillmann, Julian; Swettenham, John

    2017-02-01

    Previous studies examining selective attention in individuals with autism spectrum disorder (ASD) have yielded conflicting results, some suggesting superior focused attention (e.g., on visual search tasks), others demonstrating greater distractibility. This pattern could be accounted for by the proposal (derived by applying the Load theory of attention, e.g., Lavie, 2005) that ASD is characterized by an increased perceptual capacity (Remington, Swettenham, Campbell, & Coleman, 2009). Recent studies in the visual domain support this proposal. Here we hypothesize that ASD involves an enhanced perceptual capacity that also operates across sensory modalities, and test this prediction, for the first time using a signal detection paradigm. Seventeen neurotypical (NT) and 15 ASD adolescents performed a visual search task under varying levels of visual perceptual load while simultaneously detecting presence/absence of an auditory tone embedded in noise. Detection sensitivity (d') for the auditory stimulus was similarly high for both groups in the low visual perceptual load condition (e.g., 2 items: p = .391, d = 0.31, 95% confidence interval [CI] [-0.39, 1.00]). However, at a higher level of visual load, auditory d' reduced for the NT group but not the ASD group, leading to a group difference (p = .002, d = 1.2, 95% CI [0.44, 1.96]). As predicted, when visual perceptual load was highest, both groups then showed a similarly low auditory d' (p = .9, d = 0.05, 95% CI [-0.65, 0.74]). These findings demonstrate that increased perceptual capacity in ASD operates across modalities. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. A crossmodal crossover: opposite effects of visual and auditory perceptual load on steady-state evoked potentials to irrelevant visual stimuli.

    Science.gov (United States)

    Jacoby, Oscar; Hall, Sarah E; Mattingley, Jason B

    2012-07-16

    Mechanisms of attention are required to prioritise goal-relevant sensory events under conditions of stimulus competition. According to the perceptual load model of attention, the extent to which task-irrelevant inputs are processed is determined by the relative demands of discriminating the target: the more perceptually demanding the target task, the less unattended stimuli will be processed. Although much evidence supports the perceptual load model for competing stimuli within a single sensory modality, the effects of perceptual load in one modality on distractor processing in another is less clear. Here we used steady-state evoked potentials (SSEPs) to measure neural responses to irrelevant visual checkerboard stimuli while participants performed either a visual or auditory task that varied in perceptual load. Consistent with perceptual load theory, increasing visual task load suppressed SSEPs to the ignored visual checkerboards. In contrast, increasing auditory task load enhanced SSEPs to the ignored visual checkerboards. This enhanced neural response to irrelevant visual stimuli under auditory load suggests that exhausting capacity within one modality selectively compromises inhibitory processes required for filtering stimuli in another. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. The effect of perceptual load on tactile spatial attention: Evidence from event-related potentials.

    Science.gov (United States)

    Gherri, Elena; Berreby, Fiona

    2017-10-15

    To investigate whether tactile spatial attention is modulated by perceptual load, behavioural and electrophysiological measures were recorded during two spatial cuing tasks in which the difficulty of the target/non-target discrimination was varied (High and Low load tasks). Moreover, to study whether attentional modulations by load are sensitive to the availability of visual information, the High and Low load tasks were carried out under both illuminated and darkness conditions. ERPs to cued and uncued non-targets were compared as a function of task (High vs. Low load) and illumination condition (Light vs. Darkness). Results revealed that the locus of tactile spatial attention was determined by a complex interaction between perceptual load and illumination conditions during sensory-specific stages of processing. In the Darkness, earlier effects of attention were present in the High load than in the Low load task, while no difference between tasks emerged in the Light. By contrast, increased load was associated with stronger attention effects during later post-perceptual processing stages regardless of illumination conditions. These findings demonstrate that ERP correlates of tactile spatial attention are strongly affected by the perceptual load of the target/non-target discrimination. However, differences between illumination conditions show that the impact of load on tactile attention depends on the presence of visual information. Perceptual load is one of the many factors that contribute to determine the effects of spatial selectivity in touch. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Perceptual load modulates anterior cingulate cortex response to threat distractors in generalized social anxiety disorder.

    Science.gov (United States)

    Wheaton, Michael G; Fitzgerald, Daniel A; Phan, K Luan; Klumpp, Heide

    2014-09-01

    Generalized social anxiety disorder (gSAD) is associated with impoverished anterior cingulate cortex (ACC) engagement during attentional control. Attentional Control Theory proposes such deficiencies may be offset when demands on resources are increased to execute goals. To test the hypothesis attentional demands affect ACC response 23 patients with gSAD and 24 matched controls performed an fMRI task involving a target letter in a string of identical targets (low load) or a target letter in a mixed letter string (high load) superimposed on fearful, angry, and neutral face distractors. Regardless of load condition, groups were similar in accuracy and reaction time. Under low load gSAD patients showed deficient rostral ACC recruitment to fearful (vs. neutral) distractors. For high load, increased activation to fearful (vs. neutral) distractors was observed in gSAD suggesting a compensatory function. Results remained after controlling for group differences in depression level. Findings indicate perceptual demand modulates ACC in gSAD. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Reconceptualizing perceptual load as a rate problem: The role of time in the allocation of selective attention.

    Science.gov (United States)

    Li, Zhi; Xin, Keyun; Li, Wei; Li, Yanzhe

    2018-04-30

    In the literature about allocation of selective attention, a widely studied question is when will attention be allocated to information that is clearly irrelevant to the task at hand. The present study, by using convergent evidence, demonstrated that there is a trade-off between quantity of information present in a display and the time allowed to process it. Specifically, whether or not there is interference from irrelevant distractors depends not only on the amount of information present, but also on the amount of time allowed to process that information. When processing time is calibrated to the amount of information present, irrelevant distractors can be selectively ignored successfully. These results suggest that the perceptual load in the load theory of selective attention (i.e., Lavie, 2005) should be thought about as a dynamic rate problem rather than a static capacity limitation. The authors thus propose that rather than conceiving of perceptual load as a quantity of information, they should consider it as a quantity of information per unit of time. In other words, it is the relationship between the quantity of information in the task and the time for processing the information that determines the allocation of selective attention. Thus, the present findings extended load theory, allowing it to explain findings that were previously considered as counter evidence of load theory. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  20. Modeling the Effects of Perceptual Load: Saliency, Competitive Interactions, and Top-Down Biases.

    Science.gov (United States)

    Neokleous, Kleanthis; Shimi, Andria; Avraamides, Marios N

    2016-01-01

    A computational model of visual selective attention has been implemented to account for experimental findings on the Perceptual Load Theory (PLT) of attention. The model was designed based on existing neurophysiological findings on attentional processes with the objective to offer an explicit and biologically plausible formulation of PLT. Simulation results verified that the proposed model is capable of capturing the basic pattern of results that support the PLT as well as findings that are considered contradictory to the theory. Importantly, the model is able to reproduce the behavioral results from a dilution experiment, providing thus a way to reconcile PLT with the competing Dilution account. Overall, the model presents a novel account for explaining PLT effects on the basis of the low-level competitive interactions among neurons that represent visual input and the top-down signals that modulate neural activity. The implications of the model concerning the debate on the locus of selective attention as well as the origins of distractor interference in visual displays of varying load are discussed.

  1. Understanding the allocation of attention when faced with varying perceptual load in partial report: a computational approach.

    Science.gov (United States)

    Kyllingsbæk, Søren; Sy, Jocelyn L; Giesbrecht, Barry

    2011-05-01

    The allocation of visual processing capacity is a key topic in studies and theories of visual attention. The load theory of Lavie (1995) proposes that allocation happens in two steps where processing resources are first allocated to task-relevant stimuli and secondly remaining capacity 'spills over' to task-irrelevant distractors. In contrast, the Theory of Visual Attention (TVA) proposed by Bundesen (1990) assumes that allocation happens in a single step where processing capacity is allocated to all stimuli, both task-relevant and task-irrelevant, in proportion to their relative attentional weight. Here we present data from two partial report experiments where we varied the number and discriminability of the task-irrelevant stimuli (Experiment 1) and perceptual load (Experiment 2). The TVA fitted the data of the two experiments well thus favoring the simple explanation with a single step of capacity allocation. We also show that the effects of varying perceptual load can only be explained by a combined effect of allocation of processing capacity as well as limits in visual working memory. Finally, we link the results to processing capacity understood at the neural level based on the neural theory of visual attention by Bundesen et al. (2005). Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Perceptual representation, veridicality, and the interface theory of perception.

    Science.gov (United States)

    Cohen, Jonathan

    2015-12-01

    Hoffman, Singh, and Prakash (henceforth, HSP) argue that perception was not selected for veridical representation, hence that, contrary to a very widespread consensus, there's much less of the latter than you might expect in perception. And they put forward an alternative "interface" theory, on which perception is an adaptively useful but truth-obscuring veil between perceiver and perceived. But HSP's case against veridical perception, and their case for an alternative account, turn crucially on significant misapprehensions in the early going about what veridicality amounts to. In this paper I'll identify this mistake, and then argue that it both undercuts HSP's arguments against perceptual veridicality and prevents them from seeing that their own preferred conception of perception is itself committed to veridical representation, rather than an alternative to it. In the end, I'll conclude, HSP give us no reasons to abandon the standard view that perception veridically represents the world.

  3. Using perceptual control theory to analyse technology integration in teaching

    Directory of Open Access Journals (Sweden)

    D W Govender

    2013-07-01

    Full Text Available Contrary to the more traditional scenario of instructor-focused presentation, contemporary education allows individuals to embrace modern technological advances such as computers to concur with, conceptualize and substantiate matters presented before them. Transition from instructor-focused to student-centred presentation is prone to dissension and strife, motivating educators to assess elements of learner-centred teaching in conjunction with traditional teaching mechanisms and how individuals perceive and comprehend information (Andersson, 2008; Kiboss, 2010; United Nations Educational, Scientific and Cultural Organization (UNESCO, 2004. Computers can assist when used in the traditional teacher-student interface, but consideration must be given to teaching method variations and the students embracing these learning applications. If learner-centred teaching is to become accepted certain elements need to be introduced: revision of educators’ learning and teaching applications, time to facilitate knowledge and use of applicable contemporary technologies, and methods compatible with various technologies (Kiboss, 2010. Change is often not easy – while acknowledging the need to alter and revise methods they were taught to instil, educators may fail to embrace incorporation of technology into their teaching platform. Why are educators, who are quite knowledgeable and competent in computer applications and their merits, failing to embrace the benefits of technology in the classroom? A critical assessment of this mandates a transdisciplinary disposition in order to come to an amenable resolution. Perception, inhibition, ignorance and goals are just some reasons why educators are reluctant to incorporate technology despite their proficiency. Perceptual control theory (PCT will be implemented to assess these reasons as a means towards achieving change and assessing how to move forward. Issues associated with educators’ short- and long-term goals as

  4. The neural correlates of perceptual load induced attentional selection: an fMRI study.

    Science.gov (United States)

    Wei, P; Szameitat, A J; Müller, H J; Schubert, T; Zhou, X

    2013-10-10

    The neural correlates of perceptual load induced attentional selection were investigated in an functional magnetic resonance imaging (fMRI) experiment in which attentional selection was manipulated through the variation of perceptual load in target search. Participants searched for a vertically or horizontally oriented bar among heterogeneously (the high load condition) or homogeneously (the low load condition) oriented distractor bars in the central display, which was flanked by a vertical or horizontal bar presented at the left or the right periphery. The search reaction times were longer when the central display was of high load than of low load, and were longer when the flanker was incongruent than congruent with the target. Importantly, the flanker congruency effect was manifested only in the low load condition, not in the high load condition, indicating that the perceptual load in target search determined whether the task-irrelevant flanker was processed. Imaging analyses revealed a set of fronto-parietal regions having higher activations in the high than in the low load condition. Anterior cingulate cortex (ACC) was more activated for the incongruent than for the congruent trials. Moreover, ACC and bilateral anterior insula were sensitive to the interaction between perceptual load and flanker congruency such that the activation differences between the incongruent and congruent conditions were significant in the low, but not in the high load condition. These results are consistent with the claim that ACC and bilateral anterior insula may exert executive control by selectively biasing processing in favor of task-relevant information and this biasing depends on the resources currently available to the control system. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. Cross-modal perceptual load: the impact of modality and individual differences.

    Science.gov (United States)

    Sandhu, Rajwant; Dyson, Benjamin James

    2016-05-01

    Visual distractor processing tends to be more pronounced when the perceptual load (PL) of a task is low compared to when it is high [perpetual load theory (PLT); Lavie in J Exp Psychol Hum Percept Perform 21(3):451-468, 1995]. While PLT is well established in the visual domain, application to cross-modal processing has produced mixed results, and the current study was designed in an attempt to improve previous methodologies. First, we assessed PLT using response competition, a typical metric from the uni-modal domain. Second, we looked at the impact of auditory load on visual distractors, and of visual load on auditory distractors, within the same individual. Third, we compared individual uni- and cross-modal selective attention abilities, by correlating performance with the visual Attentional Network Test (ANT). Fourth, we obtained a measure of the relative processing efficiency between vision and audition, to investigate whether processing ease influences the extent of distractor processing. Although distractor processing was evident during both attend auditory and attend visual conditions, we found that PL did not modulate processing of either visual or auditory distractors. We also found support for a correlation between the uni-modal (visual) ANT and our cross-modal task but only when the distractors were visual. Finally, although auditory processing was more impacted by visual distractors, our measure of processing efficiency only accounted for this asymmetry in the auditory high-load condition. The results are discussed with respect to the continued debate regarding the shared or separate nature of processing resources across modalities.

  6. Power Load Prediction Based on Fractal Theory

    OpenAIRE

    Jian-Kai, Liang; Cattani, Carlo; Wan-Qing, Song

    2015-01-01

    The basic theories of load forecasting on the power system are summarized. Fractal theory, which is a new algorithm applied to load forecasting, is introduced. Based on the fractal dimension and fractal interpolation function theories, the correlation algorithms are applied to the model of short-term load forecasting. According to the process of load forecasting, the steps of every process are designed, including load data preprocessing, similar day selecting, short-term load forecasting, and...

  7. Understanding the allocation of attention when faced with varying perceptual load in partial report

    DEFF Research Database (Denmark)

    Kyllingsbæk, Søren; Sy, Jocelyn L; Giesbrecht, Barry

    2011-01-01

    . Here we present data from two partial report experiments where we varied the number and discriminability of the task-irrelevant stimuli (Experiment 1) and perceptual load (Experiment 2). The TVA fitted the data of the two experiments well thus favoring the simple explanation with a single step...

  8. N250r and N400 ERP correlates of immediate famous face repetition are independent of perceptual load.

    Science.gov (United States)

    Neumann, Markus F; Schweinberger, Stefan R

    2008-11-06

    It is a matter of considerable debate whether attention to initial stimulus presentations is required for repetition-related neural modulations to occur. Recently, it has been assumed that faces are particularly hard to ignore, and can capture attention in a reflexive manner. In line with this idea, electrophysiological evidence for long-term repetition effects of unattended famous faces has been reported. The present study investigated influences of attention to prime faces on short-term repetition effects in event-related potentials (ERPs). We manipulated attention to short (200 ms) prime presentations (S1) of task-irrelevant famous faces according to Lavie's Perceptual Load Theory. Participants attended to letter strings superimposed on face images, and identified target letters "X" vs. "N" embedded in strings of either 6 different (high load) or 6 identical (low load) letters. Letter identification was followed by probe presentations (S2), which were either repetitions of S1 faces, new famous faces, or infrequent butterflies, to which participants responded. Our ERP data revealed repetition effects in terms of an N250r at occipito-temporal regions, suggesting priming of face identification processes, and in terms of an N400 at the vertex, suggesting semantic priming. Crucially, the magnitude of these effects was unaffected by perceptual load at S1 presentation. This indicates that task-irrelevant face processing is remarkably preserved even in a demanding letter detection task, supporting recent notions of face-specific attentional resources.

  9. The influence of perceptual load on age differences in selective attention.

    Science.gov (United States)

    Maylor, E A; Lavie, N

    1998-12-01

    The effect of perceptual load on age differences in visual selective attention was examined in 2 studies. In Experiment 1, younger and older adults made speeded choice responses indicating which of 2 target letters was present in a relevant set of letters in the center of the display while they attempted to ignore an irrelevant distractor in the periphery. The perceptual load of relevant processing was manipulated by varying the central set size. When the relevant set size was small, the adverse effect of an incompatible distractor was much greater for the older participants than for the younger ones. However, with larger relevant set sizes, this was no longer the case, with the distractor effect decreasing for older participants at lower levels of perceptual load than for younger ones. In Experiment 2, older adults were tested with the empty locations in the central set either unmarked (as in Experiment 1) or marked by small circles to form a group of 6 items irrespective of set size; the 2 conditions did not differ markedly, ruling out an explanation based entirely on perceptual grouping.

  10. Twenty years of load theory-Where are we now, and where should we go next?

    Science.gov (United States)

    Murphy, Gillian; Groeger, John A; Greene, Ciara M

    2016-10-01

    Selective attention allows us to ignore what is task-irrelevant and focus on what is task-relevant. The cognitive and neural mechanisms that underlie this process are key topics of investigation in cognitive psychology. One of the more prominent theories of attention is perceptual load theory, which suggests that the efficiency of selective attention is dependent on both perceptual and cognitive load. It is now more than 20 years since the proposal of load theory, and it is a good time to evaluate the evidence in support of this influential model. The present article supplements and extends previous reviews (Lavie, Trends in Cognitive Sciences, 9, 75-82. doi: 10.1016/j.tics.2004.12.004 , 2005, Current Directions in Psychological Science, 19, 143-148. doi: 10.1177/0963721410370295 , 2010) by examining more recent research in what appears to be a rapidly expanding area. The article comprises five parts, examining (1) evidence for the effects of perceptual load on attention, (2) cognitive load, (3) individual differences under load, (4) alternative theories and criticisms, and (5) the future of load theory. We argue that the key next step for load theory will be the application of the model to real-world tasks. The potential benefits of applied attention research are numerous, and there is tentative evidence that applied research would provide strong support for the theory itself, as well as real-world benefits related to activities in which attention is crucial, such as driving and education.

  11. The impact of memory load and perceptual cues on puzzle learning by 24-month olds.

    Science.gov (United States)

    Barr, Rachel; Moser, Alecia; Rusnak, Sylvia; Zimmermann, Laura; Dickerson, Kelly; Lee, Herietta; Gerhardstein, Peter

    2016-11-01

    Early childhood is characterized by memory capacity limitations and rapid perceptual and motor development [Rovee-Collier (1996). Infant Behavior & Development, 19, 385-400]. The present study examined 2-year olds' reproduction of a sliding action to complete an abstract fish puzzle under different levels of memory load and perceptual feature support. Experimental groups were compared to baseline controls to assess spontaneous rates of production of the target actions; baseline production was low across all experiments. Memory load was manipulated in Exp. 1 by adding pieces to the puzzle, increasing sequence length from 2 to 3 items, and to 3 items plus a distractor. Although memory load did not influence how toddlers learned to manipulate the puzzle pieces, it did influence toddlers' achievement of the goal-constructing the fish. Overall, girls were better at constructing the puzzle than boys. In Exp. 2, the perceptual features of the puzzle were altered by changing shape boundaries to create a two-piece horizontally cut puzzle (displaying bilateral symmetry), and by adding a semantically supportive context to the vertically cut puzzle (iconic). Toddlers were able to achieve the goal of building the fish equally well across the 2-item puzzle types (bilateral symmetry, vertical, iconic), but how they learned to manipulate the puzzle pieces varied as a function of the perceptual features. Here, as in Exp. 1, girls showed a different pattern of performance from the boys. This study demonstrates that changes in memory capacity and perceptual processing influence both goal-directed imitation learning and motoric performance. © 2016 Wiley Periodicals, Inc.

  12. Event-related potential responses to perceptual reversals are modulated by working memory load.

    Science.gov (United States)

    Intaitė, Monika; Koivisto, Mika; Castelo-Branco, Miguel

    2014-04-01

    While viewing ambiguous figures, such as the Necker cube, the available perceptual interpretations alternate with one another. The role of higher level mechanisms in such reversals remains unclear. We tested whether perceptual reversals of discontinuously presented Necker cube pairs depend on working memory resources by manipulating cognitive load while recording event-related potentials (ERPs). The ERPs showed early enhancements of negativity, which were obtained in response to the first cube approximately 500 ms before perceived reversals. We found that working memory load influenced reversal-related brain responses in response to the second cube over occipital areas at the 150-300 ms post-stimulus and over central areas at P3 time window (300-500 ms), suggesting that it modulates intermediate visual processes. Interestingly, reversal rates remained unchanged by the working memory load. We propose that perceptual reversals in discontinuous presentation of ambiguous stimuli are governed by an early (well preceding pending reversals) mechanism, while the effects of load on the reversal related ERPs may reflect general top-down influences on visual processing, possibly mediated by the prefrontal cortex. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Opposing effects of perceptual versus working memory load on emotional distraction.

    Science.gov (United States)

    Tavares, Tamara P; Logie, Kyle; Mitchell, Derek G V

    2016-10-01

    Throughout our day-to-day activities, we are subjected to numerous stimuli that compete for our attention; consequently, we must prioritize stimuli for further processing and influence over behaviour. Previous research has demonstrated that the extent to which task-irrelevant distractors are processed is mediated by the nature of the cognitive task, and the level of processing load. Importantly though, the interaction between cognitive task, processing load, and emotional distractor processing remains unclear. This is a particularly important question given the unique ways that emotion interacts with attention, and the fact that some other forms of processing load have been shown to reduce emotional distractor encoding. In the present study, participants were presented with emotional distractors during a perceptual and working memory task, under varying levels of load. In Experiment 1, we showed that the impact of emotional distractors on behaviour was reduced under conditions of high relative to low perceptual load. However, in sharp contrast, high working memory load was associated with increased emotional distraction. Importantly, these results were replicated in Experiment 2. Overall, the impact of processing load on emotional distraction varies according to the cognitive function being performed. These results raise the intriguing possibility that working memory operations deplete some of the cognitive resources needed to control the impact of emotion on behaviour. The findings, therefore, may have important implications for clinical populations featuring cognitive dysfunction and emotional dysregulation.

  14. The incidental binding of color and shape is insensitive to the perceptual load

    Directory of Open Access Journals (Sweden)

    Hugo Cezar Palhares Ferreira

    2016-01-01

    Full Text Available Abstract The binding of information in visual short-term memory may occur incidentally when irrelevant information for the task at hand is stored together with relevant information. We investigated the process of the incidental conjunction of color and shape (Exp1 and its potential association with the selection of relevant information to the memory task (Exp2. The results in Exp1 show that color and shape are incidentally and asymmetrically conjugated: color interferes with the recognition of shape; however, shape does not interfere with the recognition of color. In Exp2, we investigated whether an increase in perceptual load would eliminate the processing of irrelevant information. The results of this experiment show that even with a high perceptual load, the incidental conjunction is not affected, and color remains to interfere with shape recognition, suggesting that the incidental conjunction is an automatic process.

  15. Perceptual load vs. dilution: the roles of attentional focus, stimulus category, and target predictability

    OpenAIRE

    Chen, Zhe; Cave, Kyle R.

    2013-01-01

    Many studies have shown that increasing the number of neutral stimuli in a display decreases distractor interference. This result has been interpreted within two different frameworks; a perceptual load account, based on a reduction in spare resources, and a dilution account, based on a degradation in distractor representation and/or an increase in crosstalk between the distractor and the neutral stimuli that contain visually similar features. In four experiments, we systematically manipulated...

  16. Deficient attention is hard to find: applying the perceptual load model of selective attention to attention deficit hyperactivity disorder subtypes.

    Science.gov (United States)

    Huang-Pollock, Cynthia L; Nigg, Joel T; Carr, Thomas H

    2005-11-01

    Whether selective attention is a primary deficit in childhood Attention Deficit Hyperactivity Disorder (ADHD) remains in active debate. We used the perceptual load paradigm to examine both early and late selective attention in children with the Primarily Inattentive (ADHD-I) and Combined subtypes (ADHD-C) of ADHD. No evidence emerged for selective attention deficits in either of the subtypes, but sluggish cognitive tempo was associated with abnormal early selection. At least some, and possibly most, children with DSM-IV ADHD have normal selective attention. Results support the move away from theories of attention dysfunction as primary in ADHD-C. In ADHD-I, this was one of the first formal tests of posterior attention network dysfunction, and results did not support that theory. However, ADHD children with sluggish cognitive tempo (SCT) warrant more study for possible early selective attention deficits.

  17. Can theories of animal discrimination explain perceptual learning in humans?

    Science.gov (United States)

    Mitchell, Chris; Hall, Geoffrey

    2014-01-01

    We present a review of recent studies of perceptual learning conducted with nonhuman animals. The focus of this research has been to elucidate the mechanisms by which mere exposure to a pair of similar stimuli can increase the ease with which those stimuli are discriminated. These studies establish an important role for 2 mechanisms, one involving inhibitory associations between the unique features of the stimuli, the other involving a long-term habituation process that enhances the relative salience of these features. We then examine recent work investigating equivalent perceptual learning procedures with human participants. Our aim is to determine the extent to which the phenomena exhibited by people are susceptible to explanation in terms of the mechanisms revealed by the animal studies. Although we find no evidence that associative inhibition contributes to the perceptual learning effect in humans, initial detection of unique features (those that allow discrimination between 2 similar stimuli) appears to depend on an habituation process. Once the unique features have been detected, a tendency to attend to those features and to learn about their properties enhances subsequent discrimination. We conclude that the effects obtained with humans engage mechanisms additional to those seen in animals but argue that, for the most part, these have their basis in learning processes that are common to animals and people. In a final section, we discuss some implications of this analysis of perceptual learning for other aspects of experimental psychology and consider some potential applications. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

  18. A look at Behaviourism and Perceptual Control Theory in Interface Design

    Science.gov (United States)

    1998-02-01

    behaviours such as response variability, instinctive drift, autoshaping , etc. Perceptual Control Theory (PCT) postulates that behaviours result from the...internal variables. Behaviourism, on the other hand, can not account for variability in responses, instinctive drift, autoshaping , etc. Researchers... Autoshaping . Animals appear to learn without reinforcement. However, conditioning theory speculates that learning results only when reinforcement

  19. Adaptation of perceptual responses to low-load blood flow restriction training

    DEFF Research Database (Denmark)

    Martín-Hernández, Juan; Ruiz-Aguado, Jorge; Herrero, Azael Juan

    2017-01-01

    The purpose of this study was to determine the adaptive response of ratings of perceived exertion (RPE) and pain over six consecutive training sessions. Thirty subjects were assigned to either a blood flow restricted training group (BFRT) or a high intensity group (HIT). BFRT group performed four...... sets (30+15+15+15, respectively) of unilateral leg extension at an intensity of 20% one repetition maximum (1RM) while a restrictive cuff was applied to the most proximal part of the leg. HIT group performed 3 sets of eight repetitions with 85%1RM. RPE and pain were assessed following every exercise.......01). No between-group differences were found at any time point. In summary, BFRT induces a high perceptual response to training. However, this perceptual response is rapidly attenuated, leading to values similar to those experienced during HIT. Low load BFRT should not be limited to highly motivated individuals...

  20. Episodic memory, perceptual memory, and their interaction: foundations for a theory of posttraumatic stress disorder.

    Science.gov (United States)

    Brewin, Chris R

    2014-01-01

    A number of autobiographical memory theories and clinical theories of posttraumatic stress disorder (PTSD) make claims that are different from standard views of memory and have been the subject of controversy. These claims include the existence of a long-term perceptual memory system supporting conscious experience separate to episodic memory; greater involvement of perceptual memory in the response to emotion-laden and personally meaningful events; increased perceptual memory intrusions accompanied by impaired episodic memory for the traumatic event among PTSD patients; and a lack of association, or inverse association, between indices of voluntary recall and involuntary images relating to the same traumatic materials. In this article I review current research on perceptual memory, which supports the presence of long-term representations that are selective or incomplete reflections of sensory input. The functional independence of perceptual and episodic memory is illustrated by research on verbal overshadowing but is most clearly exemplified by the strong evidence in favor of enhanced perceptual memory and impaired episodic memory in PTSD. Theoretical predictions concerning the relation between perceptual priming and the development of intrusive images, the effect of verbal versus visuospatial secondary tasks on intrusive trauma images, and the independence of voluntary and involuntary memory for the same materials have garnered widespread support. Reasons for the continuing controversy over traumatic memory are discussed, and some implications of the review for general theories of recall and recognition, clinical theories of PTSD, and "special mechanism" views of memory are set out. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

  1. Attentional control underlies the perceptual load effect: Evidence from voxel-wise degree centrality and resting-state functional connectivity.

    Science.gov (United States)

    Yin, Shouhang; Liu, Lu; Tan, Jinfeng; Ding, Cody; Yao, Dezhong; Chen, Antao

    2017-10-24

    The fact that interference from peripheral distracting information can be reduced in high perceptual load tasks has been widely demonstrated in previous research. The modulation from the perceptual load is known as perceptual load effect (PLE). Previous functional magnetic resonance imaging (fMRI) studies on perceptual load have reported the brain areas implicated in attentional control. To date, the contribution of attentional control to PLE and the relationship between the organization of functional connectivity and PLE are still poorly understood. In the present study, we used resting-state fMRI to explore the association between the voxel-wise degree centrality (DC) and PLE in an individual differences design and further investigated the potential resting-state functional connectivity (RSFC) contributing to individual's PLE. DC-PLE correlation analysis revealed that PLE was positively associated with the right middle temporal visual area (MT)-one of dorsal attention network (DAN) nodes. Furthermore, the right MT functionally connected to the conventional DAN and the RSFCs between right MT and DAN nodes were also positively associated with individual difference in PLE. The results suggest an important role of attentional control in perceptual load tasks and provide novel insights into the understanding of the neural correlates underlying PLE. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. Deficient Attention Is Hard to Find: Applying the Perceptual Load Model of Selective Attention to Attention Deficit Hyperactivity Disorder Subtypes

    Science.gov (United States)

    Huang-Pollock, Cynthia L.; Nigg, Joel T.; Carr, Thomas H.

    2005-01-01

    Background: Whether selective attention is a primary deficit in childhood Attention Deficit Hyperactivity Disorder (ADHD) remains in active debate. Methods: We used the "perceptual load" paradigm to examine both early and late selective attention in children with the Primarily Inattentive (ADHD-I) and Combined subtypes (ADHD-C) of ADHD. Results:…

  3. Perceptual load vs. dilution: the roles of attentional focus, stimulus category, and target predictability

    Directory of Open Access Journals (Sweden)

    Zhe eChen

    2013-06-01

    Full Text Available Many studies have shown that increasing the number of neutral stimuli in a display decreases distractor interference. This result has been interpreted within two different frameworks; a perceptual load account, based on a reduction in spare resources, and a dilution account, based on a degradation in distractor representation and/or an increase in crosstalk between the distractor and the neutral stimuli that contain visually similar features. In four experiments, we systematically manipulated the extent of attentional focus, stimulus category, and preknowledge of the target to examine how these factors would interact with the display set size to influence the degree of distractor processing. Display set size did not affect the degree of distractor processing in all situations. Increasing the number of neutral items decreased distractor processing only when a task induced a broad attentional focus that included the neutral stimuli, when the neutral stimuli were in the same category as the target and distractor, and when the preknowledge of the target was insufficient to guide attention to the target efficiently. These results suggest that the effect of neutral stimuli on the degree of distractor processing is more complex than previously assumed. They provide new insight into the competitive interactions between bottom-up and top-down processes that govern the efficiency of visual selective attention.

  4. Perceptual load vs. dilution: the roles of attentional focus, stimulus category, and target predictability.

    Science.gov (United States)

    Chen, Zhe; Cave, Kyle R

    2013-01-01

    Many studies have shown that increasing the number of neutral stimuli in a display decreases distractor interference. This result has been interpreted within two different frameworks; a perceptual load account, based on a reduction in spare resources, and a dilution account, based on a degradation in distractor representation and/or an increase in crosstalk between the distractor and the neutral stimuli that contain visually similar features. In four experiments, we systematically manipulated the extent of attentional focus, stimulus category, and preknowledge of the target to examine how these factors would interact with the display set size to influence the degree of distractor processing. Display set size did not affect the degree of distractor processing in all situations. Increasing the number of neutral items decreased distractor processing only when a task induced a broad attentional focus that included the neutral stimuli, when the neutral stimuli were in the same category as the target and distractor, and when the preknowledge of the target was insufficient to guide attention to the target efficiently. These results suggest that the effect of neutral stimuli on the degree of distractor processing is more complex than previously assumed. They provide new insight into the competitive interactions between bottom-up and top-down processes that govern the efficiency of visual selective attention.

  5. Classic debates in selective attention: early vs late, perceptual load vs dilution, mean RT vs measures of capacity.

    Science.gov (United States)

    Nelson, Michael D; Crisostomo, Marisa; Khericha, Alifiya; Russo, Francis; Thorne, Gary L

    2012-01-01

    We briefly summarize two important debates regarding selective attention (early vs late selection; perceptual load vs distractor dilution). Also, we report the results of an attempt to replicate Lavie (1995, Journal of Experimental Psychology: Human Perception and Performance 21 451-468). We suggest that measures capable of characterizing the capacity of information processing systems (compared to reporting only mean reaction time) could add great clarity to this literature.

  6. Effects of perceptual load and socially meaningful stimuli on crossmodal selective attention in Autism Spectrum Disorder and neurotypical samples.

    Science.gov (United States)

    Tyndall, Ian; Ragless, Liam; O'Hora, Denis

    2018-04-01

    The present study examined whether increasing visual perceptual load differentially affected both Socially Meaningful and Non-socially Meaningful auditory stimulus awareness in neurotypical (NT, n = 59) adults and Autism Spectrum Disorder (ASD, n = 57) adults. On a target trial, an unexpected critical auditory stimulus (CAS), either a Non-socially Meaningful ('beep' sound) or Socially Meaningful ('hi') stimulus, was played concurrently with the presentation of the visual task. Under conditions of low visual perceptual load both NT and ASD samples reliably noticed the CAS at similar rates (77-81%), whether the CAS was Socially Meaningful or Non-socially Meaningful. However, during high visual perceptual load NT and ASD participants reliably noticed the meaningful CAS (NT = 71%, ASD = 67%), but NT participants were unlikely to notice the Non-meaningful CAS (20%), whereas ASD participants reliably noticed it (80%), suggesting an inability to engage selective attention to ignore non-salient irrelevant distractor stimuli in ASD. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Cognitive Load Theory: How Many Types of Load Does It Really Need?

    Science.gov (United States)

    Kalyuga, Slava

    2011-01-01

    Cognitive load theory has been traditionally described as involving three separate and additive types of load. Germane load is considered as a learning-relevant load complementing extraneous and intrinsic load. This article argues that, in its traditional treatment, germane load is essentially indistinguishable from intrinsic load, and therefore…

  8. Load Induced Blindness

    Science.gov (United States)

    Macdonald, James S. P.; Lavie, Nilli

    2008-01-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005, for a review). Here we varied the level of…

  9. A predictive processing theory of sensorimotor contingencies: Explaining the puzzle of perceptual presence and its absence in synesthesia.

    Science.gov (United States)

    Seth, Anil K

    2014-01-01

    Normal perception involves experiencing objects within perceptual scenes as real, as existing in the world. This property of "perceptual presence" has motivated "sensorimotor theories" which understand perception to involve the mastery of sensorimotor contingencies. However, the mechanistic basis of sensorimotor contingencies and their mastery has remained unclear. Sensorimotor theory also struggles to explain instances of perception, such as synesthesia, that appear to lack perceptual presence and for which relevant sensorimotor contingencies are difficult to identify. On alternative "predictive processing" theories, perceptual content emerges from probabilistic inference on the external causes of sensory signals, however, this view has addressed neither the problem of perceptual presence nor synesthesia. Here, I describe a theory of predictive perception of sensorimotor contingencies which (1) accounts for perceptual presence in normal perception, as well as its absence in synesthesia, and (2) operationalizes the notion of sensorimotor contingencies and their mastery. The core idea is that generative models underlying perception incorporate explicitly counterfactual elements related to how sensory inputs would change on the basis of a broad repertoire of possible actions, even if those actions are not performed. These "counterfactually-rich" generative models encode sensorimotor contingencies related to repertoires of sensorimotor dependencies, with counterfactual richness determining the degree of perceptual presence associated with a stimulus. While the generative models underlying normal perception are typically counterfactually rich (reflecting a large repertoire of possible sensorimotor dependencies), those underlying synesthetic concurrents are hypothesized to be counterfactually poor. In addition to accounting for the phenomenology of synesthesia, the theory naturally accommodates phenomenological differences between a range of experiential states

  10. Selective attention to task-irrelevant emotional distractors is unaffected by the perceptual load associated with a foreground task.

    Science.gov (United States)

    Hindi Attar, Catherine; Müller, Matthias M

    2012-01-01

    A number of studies have shown that emotionally arousing stimuli are preferentially processed in the human brain. Whether or not this preference persists under increased perceptual load associated with a task at hand remains an open question. Here we manipulated two possible determinants of the attentional selection process, perceptual load associated with a foreground task and the emotional valence of concurrently presented task-irrelevant distractors. As a direct measure of sustained attentional resource allocation in early visual cortex we used steady-state visual evoked potentials (SSVEPs) elicited by distinct flicker frequencies of task and distractor stimuli. Subjects either performed a detection (low load) or discrimination (high load) task at a centrally presented symbol stream that flickered at 8.6 Hz while task-irrelevant neutral or unpleasant pictures from the International Affective Picture System (IAPS) flickered at a frequency of 12 Hz in the background of the stream. As reflected in target detection rates and SSVEP amplitudes to both task and distractor stimuli, unpleasant relative to neutral background pictures more strongly withdrew processing resources from the foreground task. Importantly, this finding was unaffected by the factor 'load' which turned out to be a weak modulator of attentional processing in human visual cortex.

  11. Selective attention to task-irrelevant emotional distractors is unaffected by the perceptual load associated with a foreground task.

    Directory of Open Access Journals (Sweden)

    Catherine Hindi Attar

    Full Text Available A number of studies have shown that emotionally arousing stimuli are preferentially processed in the human brain. Whether or not this preference persists under increased perceptual load associated with a task at hand remains an open question. Here we manipulated two possible determinants of the attentional selection process, perceptual load associated with a foreground task and the emotional valence of concurrently presented task-irrelevant distractors. As a direct measure of sustained attentional resource allocation in early visual cortex we used steady-state visual evoked potentials (SSVEPs elicited by distinct flicker frequencies of task and distractor stimuli. Subjects either performed a detection (low load or discrimination (high load task at a centrally presented symbol stream that flickered at 8.6 Hz while task-irrelevant neutral or unpleasant pictures from the International Affective Picture System (IAPS flickered at a frequency of 12 Hz in the background of the stream. As reflected in target detection rates and SSVEP amplitudes to both task and distractor stimuli, unpleasant relative to neutral background pictures more strongly withdrew processing resources from the foreground task. Importantly, this finding was unaffected by the factor 'load' which turned out to be a weak modulator of attentional processing in human visual cortex.

  12. Cognitive Load Theory: New Conceptualizations, Specifications, and Integrated Research Perspectives

    Science.gov (United States)

    Paas, Fred; van Gog, Tamara; Sweller, John

    2010-01-01

    Over the last few years, cognitive load theory has progressed and advanced rapidly. The articles in this special issue, which document those advances, are based on contributions to the 3rd International Cognitive Load Theory Conference (2009), Heerlen, The Netherlands. The articles of this special issue on cognitive load theory discuss new…

  13. Comprehensive Review on Divisible Load Theory: Concepts, Strategies, and Approaches

    Directory of Open Access Journals (Sweden)

    Shamsollah Ghanbari

    2014-01-01

    Full Text Available There is extensive literature concerning the divisible load theory. The divisible load theory is mainly applied for scheduling in the area of distributed computing. It is based on the fact that the load can be divided into some arbitrarily independent parts, in which each part can be processed independently by a processor. This paper reviews the literature concerning the divisible load theory, while focusing on the details of the basic concepts, approaches, strategies, typologies, and open problems.

  14. Testing Separability and Independence of Perceptual Dimensions with General Recognition Theory: A Tutorial and New R Package (grtools

    Directory of Open Access Journals (Sweden)

    Fabian A. Soto

    2017-05-01

    Full Text Available Determining whether perceptual properties are processed independently is an important goal in perceptual science, and tools to test independence should be widely available to experimental researchers. The best analytical tools to test for perceptual independence are provided by General Recognition Theory (GRT, a multidimensional extension of signal detection theory. Unfortunately, there is currently a lack of software implementing GRT analyses that is ready-to-use by experimental psychologists and neuroscientists with little training in computational modeling. This paper presents grtools, an R package developed with the explicit aim of providing experimentalists with the ability to perform full GRT analyses using only a couple of command lines. We describe the software and provide a practical tutorial on how to perform each of the analyses available in grtools. We also provide advice to researchers on best practices for experimental design and interpretation of results when applying GRT and grtools

  15. Testing Separability and Independence of Perceptual Dimensions with General Recognition Theory: A Tutorial and New R Package (grtools).

    Science.gov (United States)

    Soto, Fabian A; Zheng, Emily; Fonseca, Johnny; Ashby, F Gregory

    2017-01-01

    Determining whether perceptual properties are processed independently is an important goal in perceptual science, and tools to test independence should be widely available to experimental researchers. The best analytical tools to test for perceptual independence are provided by General Recognition Theory (GRT), a multidimensional extension of signal detection theory. Unfortunately, there is currently a lack of software implementing GRT analyses that is ready-to-use by experimental psychologists and neuroscientists with little training in computational modeling. This paper presents grtools , an R package developed with the explicit aim of providing experimentalists with the ability to perform full GRT analyses using only a couple of command lines. We describe the software and provide a practical tutorial on how to perform each of the analyses available in grtools . We also provide advice to researchers on best practices for experimental design and interpretation of results when applying GRT and grtools .

  16. Cognitive load theory: implications of cognitive load theory on the design of learning

    NARCIS (Netherlands)

    Kirschner, P.A.

    2002-01-01

    Cognitive load theory (CLT) can provide guidelines to assist in the presentation of information in a manner that encourages learner activities that optimise intellectual performance. It is based on a cognitive architecture that consists of a limited working memory, with partly independent

  17. Neural field theory of perceptual echo and implications for estimating brain connectivity

    Science.gov (United States)

    Robinson, P. A.; Pagès, J. C.; Gabay, N. C.; Babaie, T.; Mukta, K. N.

    2018-04-01

    Neural field theory is used to predict and analyze the phenomenon of perceptual echo in which random input stimuli at one location are correlated with electroencephalographic responses at other locations. It is shown that this echo correlation (EC) yields an estimate of the transfer function from the stimulated point to other locations. Modal analysis then explains the observed spatiotemporal structure of visually driven EC and the dominance of the alpha frequency; two eigenmodes of similar amplitude dominate the response, leading to temporal beating and a line of low correlation that runs from the crown of the head toward the ears. These effects result from mode splitting and symmetry breaking caused by interhemispheric coupling and cortical folding. It is shown how eigenmodes obtained from functional magnetic resonance imaging experiments can be combined with temporal dynamics from EC or other evoked responses to estimate the spatiotemporal transfer function between any two points and hence their effective connectivity.

  18. Effects of working memory contents and perceptual load on distractor processing: When a response-related distractor is held in working memory.

    Science.gov (United States)

    Koshino, Hideya

    2017-01-01

    Working memory and attention are closely related. Recent research has shown that working memory can be viewed as internally directed attention. Working memory can affect attention in at least two ways. One is the effect of working memory load on attention, and the other is the effect of working memory contents on attention. In the present study, an interaction between working memory contents and perceptual load in distractor processing was investigated. Participants performed a perceptual load task in a standard form in one condition (Single task). In the other condition, a response-related distractor was maintained in working memory, rather than presented in the same stimulus display as a target (Dual task). For the Dual task condition, a significant compatibility effect was found under high perceptual load; however, there was no compatibility effect under low perceptual load. These results suggest that the way the contents of working memory affect visual search depends on perceptual load. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Cognitive load theory: New conceptualizations, specifications, and integrated research perspectives

    NARCIS (Netherlands)

    G.W.C. Paas (Fred); T.A.J.M. van Gog (Tamara); J. Sweller (John)

    2010-01-01

    textabstractOver the last few years, cognitive load theory has progressed and advanced rapidly. The articles in this special issue, which document those advances, are based on contributions to the 3rd International Cognitive Load Theory Conference (2009), Heerlen, The Netherlands. The articles of

  20. Cognitive Load Theory: Advances in Research on Worked Examples, Animations, and Cognitive Load Measurement

    NARCIS (Netherlands)

    T.A.J.M. van Gog (Tamara); G.W.C. Paas (Fred); J. Sweller (John)

    2010-01-01

    textabstractThe contributions to this special issue document some recent advances of cognitive load theory, and are based on contributions to the Third International Cognitive Load Theory Conference (2009), Heerlen, The Netherlands. The contributions focus on developments in example-based learning,

  1. Theory and practice of perceptual video processing in broadcast encoders for cable, IPTV, satellite, and internet distribution

    Science.gov (United States)

    McCarthy, S.

    2014-02-01

    This paper describes the theory and application of a perceptually-inspired video processing technology that was recently incorporated into professional video encoders now being used by major cable, IPTV, satellite, and internet video service providers. We will present data that show that this perceptual video processing (PVP) technology can improve video compression efficiency by up to 50% for MPEG-2, H.264, and High Efficiency Video Coding (HEVC). The PVP technology described in this paper works by forming predicted eye-tracking attractor maps that indicate how likely it might be that a free viewing person would look at particular area of an image or video. We will introduce in this paper the novel model and supporting theory used to calculate the eye-tracking attractor maps. We will show how the underlying perceptual model was inspired by electrophysiological studies of the vertebrate retina, and will explain how the model incorporates statistical expectations about natural scenes as well as a novel method for predicting error in signal estimation tasks. Finally, we will describe how the eye-tracking attractor maps are created in real time and used to modify video prior to encoding so that it is more compressible but not noticeably different than the original unmodified video.

  2. Effect of Perceptual Load on Semantic Access by Speech in Children

    Science.gov (United States)

    Jerger, Susan; Damian, Markus F.; Mills, Candice; Bartlett, James; Tye-Murray, Nancy; Abdi, Herve

    2013-01-01

    Purpose: To examine whether semantic access by speech requires attention in children. Method: Children ("N" = 200) named pictures and ignored distractors on a cross-modal (distractors: auditory-no face) or multimodal (distractors: auditory-static face and audiovisual- dynamic face) picture word task. The cross-modal task had a low load,…

  3. Fatigue and perceptual responses of heavier- and lighter-load isolated lumbar extension resistance exercise in males and females

    Directory of Open Access Journals (Sweden)

    Charlotte Stuart

    2018-03-01

    Full Text Available Background There is a lack of research considering acute fatigue responses to high- and low-load resistance training as well as the comparison between male and female responses. Furthermore, limited studies have considered fatigue response testing with the inclusion of perceptions of discomfort and exertion. Methods The present study included males (n = 9; 23.8 ± 6.4 years; 176.7 ± 6.2 cm; 73.9 ± 9.3 kg and females (n = 8; 21.3 ± 0.9 years; 170.5 ± 6.1 cm; 65.5 ± 10.8 kg who were assessed for differences in fatigue (i.e., loss of torque at maximal voluntary contraction (MVC immediately following isolated lumbar extension (ILEX exercise at heavy- (HL and light-(LL loads (80% and 50% MVC, respectively. Participants also reported perceptual measures of effort (RPE-E and discomfort (RPE-D between different resistance training protocols. Results Analysis of variance revealed significantly greater absolute and relative fatigue following LL compared to HL conditions (p < 0.001. Absolute fatigue significantly differed between males and females (p = 0.012, though relative fatigue was not significantly different (p = 0.160. However, effect sizes for absolute fatigue (HL; Males = −1.84, Females = −0.83; LL; Males = −3.11, Females = −2.39 and relative fatigue (HL; Males = −2.17, Females = −0.76; LL; Males = −3.36, Females = −3.08 were larger for males in both HL and LL conditions. RPE-E was maximal for all participants in both conditions, but RPE-D was significantly higher in LL compared to HL (p < 0.001 with no difference between males and females. Discussion Our data suggests that females do not incur the same degree of fatigue as males following similar exercise protocols, and indeed that females might be able to sustain longer exercise duration at the same relative loads. As such females should manipulate training variables accordingly, perhaps performing greater repetitions at a relative load, or using heavier relative

  4. Opposite Effects of Capacity Load and Resolution Load on Distractor Processing

    OpenAIRE

    Zhang, Weiwei; Luck, Steven J.

    2014-01-01

    According to the load theory of attention, an increased perceptual load reduces distractor processing whereas an increased working memory load facilitates distractor processing. Here we raise the possibility that the critical distinction may instead be between an emphasis on resolution and an emphasis on capacity. That is, perceptual load manipulations typically emphasize resolution (fine-grained discriminations), whereas working memory load manipulations typically emphasize capacity (simulta...

  5. Accurate expectancies diminish perceptual distraction during visual search

    Science.gov (United States)

    Sy, Jocelyn L.; Guerin, Scott A.; Stegman, Anna; Giesbrecht, Barry

    2014-01-01

    The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively “spills-over” to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information. PMID:24904374

  6. Accurate expectancies diminish perceptual distraction during visual search

    Directory of Open Access Journals (Sweden)

    Jocelyn L Sy

    2014-05-01

    Full Text Available The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively spills-over to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, fMRI, and electrophysiology. Expectations were generated by a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean BOLD responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information.

  7. Cognitive load theory: Practical implications and an important challenge

    Directory of Open Access Journals (Sweden)

    Jimmie Leppink, Ph.D.

    2017-10-01

    Full Text Available The field of medical education has adopted a wide variety of theories from other fields. A fairly recent example is cognitive load theory, which originated in educational psychology. Several empirical studies inspired by cognitive load theory and reviews of practical implications of cognitive load theory have contributed to guidelines for the design of medical education. Simultaneously, several research groups have developed instruments for the measurement of cognitive load in a medical education context. These developments notwithstanding, obtaining evidence for different types of cognitive load remains an important challenge. Therefore, the aim of this article is twofold: to provide medical educators with three key guidelines for the design of instruction and assessment and to discuss several fundamental issues in the remaining challenges presented by different types of cognitive load. The guidelines revolve around minimizing cognitive activity that does not contribute to learning, working with specific learning goals in mind, and appreciating the multifaceted relation between learning and assessment. Key issues around the types of cognitive load include the context in which learning occurs, the continued use of single-item mental effort ratings, and the timing of cognitive load and learning outcome measurements.

  8. Rethinking the Boundaries of Cognitive Load Theory in Complex Learning

    Science.gov (United States)

    Kalyuga, Slava; Singh, Anne-Marie

    2016-01-01

    In the traditional framework of cognitive load theory, it is assumed that the acquisition of domain-specific knowledge structures (or schemas) is the only instructional goal, and therefore, the theory is applicable to any instructional task. Accordingly, the basic concepts of intrinsic (productive) and extraneous (unproductive) types of cognitive…

  9. Cognitive load measurement as a means to advance cognitive load theory

    NARCIS (Netherlands)

    Paas, F.; Tuovinen, J.E.; Tabbers, H.; van Gerven, P.W.M.

    2003-01-01

    This paper discusses cognitive load measurement techniques with regard to their contribution to cognitive load theory (CLT). CLT is concerned with the design of instructional methods that efficiently use people's limited cognitive processing capacity to apply acquired knowledge and skills to new

  10. Using game theory for perceptual tuned rate control algorithm in video coding

    Science.gov (United States)

    Luo, Jiancong; Ahmad, Ishfaq

    2005-03-01

    This paper proposes a game theoretical rate control technique for video compression. Using a cooperative gaming approach, which has been utilized in several branches of natural and social sciences because of its enormous potential for solving constrained optimization problems, we propose a dual-level scheme to optimize the perceptual quality while guaranteeing "fairness" in bit allocation among macroblocks. At the frame level, the algorithm allocates target bits to frames based on their coding complexity. At the macroblock level, the algorithm distributes bits to macroblocks by defining a bargaining game. Macroblocks play cooperatively to compete for shares of resources (bits) to optimize their quantization scales while considering the Human Visual System"s perceptual property. Since the whole frame is an entity perceived by viewers, macroblocks compete cooperatively under a global objective of achieving the best quality with the given bit constraint. The major advantage of the proposed approach is that the cooperative game leads to an optimal and fair bit allocation strategy based on the Nash Bargaining Solution. Another advantage is that it allows multi-objective optimization with multiple decision makers (macroblocks). The simulation results testify the algorithm"s ability to achieve accurate bit rate with good perceptual quality, and to maintain a stable buffer level.

  11. Perceptual inference.

    Science.gov (United States)

    Aggelopoulos, Nikolaos C

    2015-08-01

    Perceptual inference refers to the ability to infer sensory stimuli from predictions that result from internal neural representations built through prior experience. Methods of Bayesian statistical inference and decision theory model cognition adequately by using error sensing either in guiding action or in "generative" models that predict the sensory information. In this framework, perception can be seen as a process qualitatively distinct from sensation, a process of information evaluation using previously acquired and stored representations (memories) that is guided by sensory feedback. The stored representations can be utilised as internal models of sensory stimuli enabling long term associations, for example in operant conditioning. Evidence for perceptual inference is contributed by such phenomena as the cortical co-localisation of object perception with object memory, the response invariance in the responses of some neurons to variations in the stimulus, as well as from situations in which perception can be dissociated from sensation. In the context of perceptual inference, sensory areas of the cerebral cortex that have been facilitated by a priming signal may be regarded as comparators in a closed feedback loop, similar to the better known motor reflexes in the sensorimotor system. The adult cerebral cortex can be regarded as similar to a servomechanism, in using sensory feedback to correct internal models, producing predictions of the outside world on the basis of past experience. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Surface loading of a viscoelastic earth-I. General theory

    Science.gov (United States)

    Tromp, Jeroen; Mitrovica, Jerry X.

    1999-06-01

    We present a new normal-mode formalism for computing the response of an aspherical, self-gravitating, linear viscoelastic earth model to an arbitrary surface load. The formalism makes use of recent advances in the theory of the Earth's free oscillations, and is based upon an eigenfunction expansion methodology, rather than the tradi-tional Love-number approach to surface-loading problems. We introduce a surface-load representation theorem analogous to Betti's reciprocity relation in seismology. Taking advantage of this theorem and the biorthogonality of the viscoelastic modes, we determine the complete response to a surface load in the form of a Green's function. We also demonstrate that each viscoelastic mode has its own unique energy partitioning, which can be used to characterize it. In subsequent papers, we apply the theory to spherically symmetric and aspherical earth models.

  13. The Impact of Cognitive Load Theory on Learning Astronomy

    Science.gov (United States)

    Foster, Thomas M.

    2010-01-01

    Every student is different, which is the challenge of astronomy education research (AER) and teaching astronomy. This difference also provides the greatest goal for education researchers - our GUT - we need to be able to quantify these differences and provide explanatory and predictive theories to curriculum developers and teachers. One educational theory that holds promise is Cognitive Load Theory. Cognitive Load Theory begins with the well-established fact that everyone's working memory can hold 7 ± 2 unique items. This quirk of the human brain is why phone numbers are 7 digits long. This quirk is also why we forget peoples’ names after just meeting them, leave the iron on when we leave the house, and become overwhelmed as students of new material. Once the intricacies of Cognitive Load are understood, it becomes possible to design learning environments to marshal the resources students have and guide them to success. Lessons learned from Cognitive Load Theory can and should be applied to learning astronomy. Classroom-ready ideas will be presented.

  14. Dilution: A Theoretical Burden or Just Load? A Reply to Tsal and Benoni (2010)

    Science.gov (United States)

    Lavie, Nilli; Torralbo, Ana

    2010-01-01

    Load theory of attention proposes that distractor processing is reduced in tasks with high perceptual load that exhaust attentional capacity within task-relevant processing. In contrast, tasks of low perceptual load leave spare capacity that spills over, resulting in the perception of task-irrelevant, potentially distracting stimuli. Tsal and…

  15. Perceptual Processing Affects Conceptual Processing

    Science.gov (United States)

    van Dantzig, Saskia; Pecher, Diane; Zeelenberg, Rene; Barsalou, Lawrence W.

    2008-01-01

    According to the Perceptual Symbols Theory of cognition (Barsalou, 1999), modality-specific simulations underlie the representation of concepts. A strong prediction of this view is that perceptual processing affects conceptual processing. In this study, participants performed a perceptual detection task and a conceptual property-verification task…

  16. The Two-Systems Account of Theory of Mind: Testing the Links to Social- Perceptual and Cognitive Abilities

    Directory of Open Access Journals (Sweden)

    Bozana Meinhardt-Injac

    2018-01-01

    Full Text Available According to the two-systems account of theory of mind (ToM, understanding mental states of others involves both fast social-perceptual processes, as well as slower, reflexive cognitive operations (Frith and Frith, 2008; Apperly and Butterfill, 2009. To test the respective roles of specific abilities in either of these processes we administered 15 experimental procedures to a large sample of 343 participants, testing ability in face recognition and holistic perception, language, and reasoning. ToM was measured by a set of tasks requiring ability to track and to infer complex emotional and mental states of others from faces, eyes, spoken language, and prosody. We used structural equation modeling to test the relative strengths of a social-perceptual (face processing related and reflexive-cognitive (language and reasoning related path in predicting ToM ability. The two paths accounted for 58% of ToM variance, thus validating a general two-systems framework. Testing specific predictor paths revealed language and face recognition as strong and significant predictors of ToM. For reasoning, there were neither direct nor mediated effects, albeit reasoning was strongly associated with language. Holistic face perception also failed to show a direct link with ToM ability, while there was a mediated effect via face recognition. These results highlight the respective roles of face recognition and language for the social brain, and contribute closer empirical specification of the general two-systems account.

  17. Scalable Content Authentication in H.264/SVC Videos Using Perceptual Hashing based on Dempster-Shafer theory

    Directory of Open Access Journals (Sweden)

    Ye Dengpan

    2012-09-01

    Full Text Available The content authenticity of the multimedia delivery is important issue with rapid development and widely used of multimedia technology. Till now many authentication solutions had been proposed, such as cryptology and watermarking based methods. However, in latest heterogeneous network the video stream transmission has been coded in scalable way such as H.264/SVC, there is still no good authentication solution. In this paper, we firstly summarized related works and proposed a scalable content authentication scheme using a ratio of different energy (RDE based perceptual hashing in Q/S dimension, which is used Dempster-Shafer theory and combined with the latest scalable video coding (H.264/SVC construction. The idea of aldquo;sign once and verify in scalable wayardquo; can be realized. Comparing with previous methods, the proposed scheme based on perceptual hashing outperforms previous works in uncertainty (robustness and efficiencies in the H.264/SVC video streams. At last, the experiment results verified the performance of our scheme.

  18. The Two-Systems Account of Theory of Mind: Testing the Links to Social- Perceptual and Cognitive Abilities.

    Science.gov (United States)

    Meinhardt-Injac, Bozana; Daum, Moritz M; Meinhardt, Günter; Persike, Malte

    2018-01-01

    According to the two-systems account of theory of mind (ToM), understanding mental states of others involves both fast social-perceptual processes, as well as slower, reflexive cognitive operations (Frith and Frith, 2008; Apperly and Butterfill, 2009). To test the respective roles of specific abilities in either of these processes we administered 15 experimental procedures to a large sample of 343 participants, testing ability in face recognition and holistic perception, language, and reasoning. ToM was measured by a set of tasks requiring ability to track and to infer complex emotional and mental states of others from faces, eyes, spoken language, and prosody. We used structural equation modeling to test the relative strengths of a social-perceptual (face processing related) and reflexive-cognitive (language and reasoning related) path in predicting ToM ability. The two paths accounted for 58% of ToM variance, thus validating a general two-systems framework. Testing specific predictor paths revealed language and face recognition as strong and significant predictors of ToM. For reasoning, there were neither direct nor mediated effects, albeit reasoning was strongly associated with language. Holistic face perception also failed to show a direct link with ToM ability, while there was a mediated effect via face recognition. These results highlight the respective roles of face recognition and language for the social brain, and contribute closer empirical specification of the general two-systems account.

  19. Applying Cognitive Load Theory Principles to Library Instructional Guidance

    Science.gov (United States)

    Pickens, Kathleen E.

    2017-01-01

    If the goal of library instructional guidance is to provide students with the knowledge needed to acquire new skills in order to accomplish their learning objectives, then it is prudent to consider factors that impact learning. Cognitive load theory addresses several of these factors and is applicable to a wide-range of instructional devices used…

  20. Cognitive Load Theory--Sometimes Less Is More

    Science.gov (United States)

    Taylor, Cody

    2013-01-01

    The following paper represents review of the literature examining the current research related to cognitive load theory and more specifically the negative aspects of the redundant on-screen text. The authors describe working and long-term memory and how both factor into human learning through the facilitation of knowledge transfer. Limited working…

  1. General recognition theory with individual differences: a new method for examining perceptual and decisional interactions with an application to face perception.

    Science.gov (United States)

    Soto, Fabian A; Vucovich, Lauren; Musgrave, Robert; Ashby, F Gregory

    2015-02-01

    A common question in perceptual science is to what extent different stimulus dimensions are processed independently. General recognition theory (GRT) offers a formal framework via which different notions of independence can be defined and tested rigorously, while also dissociating perceptual from decisional factors. This article presents a new GRT model that overcomes several shortcomings with previous approaches, including a clearer separation between perceptual and decisional processes and a more complete description of such processes. The model assumes that different individuals share similar perceptual representations, but vary in their attention to dimensions and in the decisional strategies they use. We apply the model to the analysis of interactions between identity and emotional expression during face recognition. The results of previous research aimed at this problem have been disparate. Participants identified four faces, which resulted from the combination of two identities and two expressions. An analysis using the new GRT model showed a complex pattern of dimensional interactions. The perception of emotional expression was not affected by changes in identity, but the perception of identity was affected by changes in emotional expression. There were violations of decisional separability of expression from identity and of identity from expression, with the former being more consistent across participants than the latter. One explanation for the disparate results in the literature is that decisional strategies may have varied across studies and influenced the results of tests of perceptual interactions, as previous studies lacked the ability to dissociate between perceptual and decisional interactions.

  2. Investigation of Perceptual-Motor Behavior Across the Expert Athlete to Disabled Patient Skill Continuum can Advance Theory and Practical Application.

    Science.gov (United States)

    Müller, Sean; Vallence, Ann-Maree; Winstein, Carolee

    2017-12-14

    A framework is presented of how theoretical predictions can be tested across the expert athlete to disabled patient skill continuum. Common-coding theory is used as the exemplar to discuss sensory and motor system contributions to perceptual-motor behavior. Behavioral and neural studies investigating expert athletes and patients recovering from cerebral stroke are reviewed. They provide evidence of bi-directional contributions of visual and motor systems to perceptual-motor behavior. Majority of this research is focused on perceptual-motor performance or learning, with less on transfer. The field is ripe for research designed to test theoretical predictions across the expert athlete to disabled patient skill continuum. Our view has implications for theory and practice in sports science, physical education, and rehabilitation.

  3. A Neo-Piagetian Theory of Constructive Operators: Applications to Perceptual-Motor Development and Learning.

    Science.gov (United States)

    Todor, John I.

    The author presents an overview of Pascual-Leone's Theory of Constructive Operators, a process-structural theory based upon Piagetian constructs which has evolved to both explain and predict the temporal unfolding of behavior. An application is made of the theory to the demands of a discrete motor task and prediction of (a) the minimal age…

  4. Visual Perceptual Learning and Models.

    Science.gov (United States)

    Dosher, Barbara; Lu, Zhong-Lin

    2017-09-15

    Visual perceptual learning through practice or training can significantly improve performance on visual tasks. Originally seen as a manifestation of plasticity in the primary visual cortex, perceptual learning is more readily understood as improvements in the function of brain networks that integrate processes, including sensory representations, decision, attention, and reward, and balance plasticity with system stability. This review considers the primary phenomena of perceptual learning, theories of perceptual learning, and perceptual learning's effect on signal and noise in visual processing and decision. Models, especially computational models, play a key role in behavioral and physiological investigations of the mechanisms of perceptual learning and for understanding, predicting, and optimizing human perceptual processes, learning, and performance. Performance improvements resulting from reweighting or readout of sensory inputs to decision provide a strong theoretical framework for interpreting perceptual learning and transfer that may prove useful in optimizing learning in real-world applications.

  5. What does germane load mean? An empirical contribution to the cognitive load theory.

    Science.gov (United States)

    Debue, Nicolas; van de Leemput, Cécile

    2014-01-01

    While over the last decades, much attention has been paid to the mental workload in the field of human computer interactions, there is still a lack of consensus concerning the factors that generate it as well as the measurement methods that could reflect workload variations. Based on the multifactorial Cognitive Load Theory (CLT), our study aims to provide some food for thought about the subjective and objective measurement that can be used to disentangle the intrinsic, extraneous, and germane load. The purpose is to provide insight into the way cognitive load can explain how users' cognitive resources are allocated in the use of hypermedia, such as an online newspaper. A two-phase experiment has been conducted on the information retention from online news stories. Phase 1 (92 participants) examined the influence of multimedia content on performance as well as the relationships between cognitive loads and cognitive absorption. In Phase 2 (36 participants), eye-tracking data were collected in order to provide reliable and objective measures. Results confirmed that performance in information retention was impacted by the presence of multimedia content such as animations and pictures. The higher number of fixations on these animations suggests that users' attention could have been attracted by them. Results showed the expected opposite relationships between germane and extraneous load, a positive association between germane load and cognitive absorption and a non-linear association between intrinsic and germane load. The trends based on eye-tracking data analysis provide some interesting findings about the relationship between longer fixations, shorter saccades and cognitive load. Some issues are raised about the respective contribution of mean pupil diameter and Index of Cognitive Activity.

  6. Normal loads program for aerodynamic lifting surface theory. [evaluation of spanwise and chordwise loading distributions

    Science.gov (United States)

    Medan, R. T.; Ray, K. S.

    1974-01-01

    A description of and users manual are presented for a U.S.A. FORTRAN 4 computer program which evaluates spanwise and chordwise loading distributions, lift coefficient, pitching moment coefficient, and other stability derivatives for thin wings in linearized, steady, subsonic flow. The program is based on a kernel function method lifting surface theory and is applicable to a large class of planforms including asymmetrical ones and ones with mixed straight and curved edges.

  7. Load theory behind the wheel: an experimental application of a cognitive model to simulated driving

    OpenAIRE

    Murphy, Gillian

    2017-01-01

    Load Theory is a prominent model of selective attention first proposed over twenty years ago. Load Theory is supported by a great many experimental and neuroimaging studies. There is however, little evidence that Load Theory can be applied to real world attention, though it has great practical potential. Driving, as an everyday task where failures of attention can have profound consequences, stands to benefit from the understanding of selective attention that Load Theory provides. The aim of ...

  8. The Persistence of Erroneous Familiarity in an Epileptic Male: Challenging Perceptual Theories of Deja Vu Activation

    Science.gov (United States)

    O'Connor, Akira R.; Moulin, Christopher J. A.

    2008-01-01

    We report the case of a 39-year-old, temporal lobe epileptic male, MH. Prior to complex partial seizure, experienced up to three times a day, MH often experiences an aura experienced as a persistent sensation of deja vu. Data-driven theories of deja vu formation suggest that partial familiarity for the perceived stimulus is responsible for the…

  9. Developing feasible loading patterns using perturbation theory methods

    International Nuclear Information System (INIS)

    White, J.R.; Avila, K.M.

    1990-01-01

    This work illustrates an approach to core reload design that combines the power of integer programming with the efficiency of generalized perturbation theory. The main use of the method is as a tool to help the design engineer identify feasible loading patterns with minimum time and effort. The technique is highly successful for the burnable poison (BP) loading problem, but the unpredictable behavior of the branch-and-bound algorithm degrades overall performance for large problems. Unfortunately, the combined fuel shuffling plus BP optimization problem falls into this latter classification. Overall, however, the method shows great promise for significantly reducing the manpower time required for the reload design process. And it may even give the further benefit of better designs and improved performance

  10. PEMBELAJARAN BERBANTUAN MULTIMEDIA BERDASARKAN COGNITIVE LOAD THEORY PADA PELAJARAN MATEMATIKA SD

    Directory of Open Access Journals (Sweden)

    Rissa Prima Kurniawati

    2016-11-01

    Full Text Available Multimedia is media that combine two or more elements are composed of text, graphics, images, photographs, audio, video, and animation are integrated. In multimedia-assisted learning, students are given the opportunity to learn not only of learning resources such as teachers, but give the opportunity to students to develop better cognitive, creative, and innovative. Cognitive Load Theory is a theory that was introduced as a teaching theory based on the knowledge of human cognitive architecture that we have. The main principle of Cognitive Load Theory is the quality of learning is enhanced if attention is concentrated on the role and limitations of working memory. Three cognitive load in working memory, which is intrinsic cognitive load, Germany cognitive load, and extraneous cognitive load.   Keywords: Multimedia, Cognitive Load Theory, intrinsic cognitive load, Germany cognitive load, and extraneous cognitive load.

  11. What does germane load mean? An empirical contribution to the cognitive load theory

    Directory of Open Access Journals (Sweden)

    Nicolas eDebue

    2014-10-01

    Full Text Available While over the last decades, much attention has been paid to the mental workload in the field of human computer interactions, there is still a lack of consensus concerning the factors that generate it as well as the measurement methods that could reflect workload variations. Based on the multifactorial Cognitive Load Theory, our study aims to provide some food for thought about the subjective and objective measurement that can be used to disentangle the intrinsic, extraneous and germane load. The purpose is to provide insight into the way cognitive load can explain how users’ cognitive resources are allocated in the use of hypermedia, such as an online newspaper. A two-phase experiment has been conducted on the information retention from online news stories. Phase 1 (92 participants examined the influence of multimedia content on performance as well as the relationships between cognitive loads and cognitive absorption. In Phase 2 (36 participants, eye-tracking data were collected in order to provide reliable and objective measures. Results confirmed that performance in information retention was impacted by the presence of multimedia content such as animations and pictures. The higher number of fixations on these animations suggests that users’ attention could have been attracted by them. Results showed the expected opposite relationships between Germane and Extraneous Load, a positive association between GL and cognitive absorption and a nonlinear association between Intrinsic and Germane Load. The trends based on eye-tracking data analysis provide some interesting findings about the relationships between longer fixations, shorter saccades and cognitive load. Some issues are raised about the respective contribution of mean pupil diameter and Index of Cognitive Activity.

  12. Perceptual learning.

    Science.gov (United States)

    Seitz, Aaron R

    2017-07-10

    Perceptual learning refers to how experience can change the way we perceive sights, sounds, smells, tastes, and touch. Examples abound: music training improves our ability to discern tones; experience with food and wines can refine our pallet (and unfortunately more quickly empty our wallet), and with years of training radiologists learn to save lives by discerning subtle details of images that escape the notice of untrained viewers. We often take perceptual learning for granted, but it has a profound impact on how we perceive the world. In this Primer, I will explain how perceptual learning is transformative in guiding our perceptual processes, how research into perceptual learning provides insight into fundamental mechanisms of learning and brain processes, and how knowledge of perceptual learning can be used to develop more effective training approaches for those requiring expert perceptual skills or those in need of perceptual rehabilitation (such as individuals with poor vision). I will make a case that perceptual learning is ubiquitous, scientifically interesting, and has substantial practical utility to us all. Copyright © 2017. Published by Elsevier Ltd.

  13. Cognitive load disrupts implicit theory-of-mind processing.

    Science.gov (United States)

    Schneider, Dana; Lam, Rebecca; Bayliss, Andrew P; Dux, Paul E

    2012-08-01

    Eye movements in Sally-Anne false-belief tasks appear to reflect the ability to implicitly monitor the mental states of other individuals (theory of mind, or ToM). It has recently been proposed that an early-developing, efficient, and automatically operating ToM system subserves this ability. Surprisingly absent from the literature, however, is an empirical test of the influence of domain-general executive processing resources on this implicit ToM system. In the study reported here, a dual-task method was employed to investigate the impact of executive load on eye movements in an implicit Sally-Anne false-belief task. Under no-load conditions, adult participants displayed eye movement behavior consistent with implicit belief processing, whereas evidence for belief processing was absent for participants under cognitive load. These findings indicate that the cognitive system responsible for implicitly tracking beliefs draws at least minimally on executive processing resources. Thus, even the most low-level processing of beliefs appears to reflect a capacity-limited operation.

  14. The Scientific Value of Cognitive Load Theory: A Research Agenda Based on the Structuralist View of Theories

    Science.gov (United States)

    Gerjets, Peter; Scheiter, Katharina; Cierniak, Gabriele

    2009-01-01

    In this paper, two methodological perspectives are used to elaborate on the value of cognitive load theory (CLT) as a scientific theory. According to the more traditional critical rationalism of Karl Popper, CLT cannot be considered a scientific theory because some of its fundamental assumptions cannot be tested empirically and are thus not…

  15. Visual short-term memory load strengthens selective attention.

    Science.gov (United States)

    Roper, Zachary J J; Vecera, Shaun P

    2014-04-01

    Perceptual load theory accounts for many attentional phenomena; however, its mechanism remains elusive because it invokes underspecified attentional resources. Recent dual-task evidence has revealed that a concurrent visual short-term memory (VSTM) load slows visual search and reduces contrast sensitivity, but it is unknown whether a VSTM load also constricts attention in a canonical perceptual load task. If attentional selection draws upon VSTM resources, then distraction effects-which measure attentional "spill-over"-will be reduced as competition for resources increases. Observers performed a low perceptual load flanker task during the delay period of a VSTM change detection task. We observed a reduction of the flanker effect in the perceptual load task as a function of increasing concurrent VSTM load. These findings were not due to perceptual-level interactions between the physical displays of the two tasks. Our findings suggest that perceptual representations of distractor stimuli compete with the maintenance of visual representations held in memory. We conclude that access to VSTM determines the degree of attentional selectivity; when VSTM is not completely taxed, it is more likely for task-irrelevant items to be consolidated and, consequently, affect responses. The "resources" hypothesized by load theory are at least partly mnemonic in nature, due to the strong correspondence they share with VSTM capacity.

  16. Towards Cognitive Load Theory as Guideline for Instructional Design in Science Education

    Science.gov (United States)

    Meissner, Barbara; Bogner, Franz X.

    2013-01-01

    We applied cognitive load theory in an heuristic out-of-school science lesson. The lesson comprises experiments concerning major attributes of NaCl and was designed for 5th to 8th grade students. Our interest focused on whether cognitive load theory provides sufficient guidelines for instructional design in the field of heuristic science…

  17. Effects of load and maintenance duration on the time course of information encoding and retrieval in working memory: from perceptual analysis to post-categorization processes.

    Science.gov (United States)

    Pinal, Diego; Zurrón, Montserrat; Díaz, Fernando

    2014-01-01

    information encoding, maintenance, and retrieval; these are supported by brain activity in a network of frontal, parietal and temporal regions. Manipulation of WM load and duration of the maintenance period can modulate this activity. Although such modulations have been widely studied using the event-related potentials (ERP) technique, a precise description of the time course of brain activity during encoding and retrieval is still required. Here, we used this technique and principal component analysis to assess the time course of brain activity during encoding and retrieval in a delayed match to sample task. We also investigated the effects of memory load and duration of the maintenance period on ERP activity. Brain activity was similar during information encoding and retrieval and comprised six temporal factors, which closely matched the latency and scalp distribution of some ERP components: P1, N1, P2, N2, P300, and a slow wave. Changes in memory load modulated task performance and yielded variations in frontal lobe activation. Moreover, the P300 amplitude was smaller in the high than in the low load condition during encoding and retrieval. Conversely, the slow wave amplitude was higher in the high than in the low load condition during encoding, and the same was true for the N2 amplitude during retrieval. Thus, during encoding, memory load appears to modulate the processing resources for context updating and post-categorization processes, and during retrieval it modulates resources for stimulus classification and context updating. Besides, despite the lack of differences in task performance related to duration of the maintenance period, larger N2 amplitude and stronger activation of the left temporal lobe after long than after short maintenance periods were found during information retrieval. Thus, results regarding the duration of maintenance period were complex, and future work is required to test the time-based decay theory predictions.

  18. Effects of load and maintenance duration on the time course of information encoding and retrieval in working memory: from perceptual analysis to post-categorization processes.

    Directory of Open Access Journals (Sweden)

    Diego ePinal

    2014-04-01

    Full Text Available Working memory (WM involves three cognitive events: information encoding, maintenance and retrieval; these are supported by brain activity in a network of frontal, parietal and temporal regions. Manipulation of WM load and duration of the maintenance period can modulate this activity. Although such modulations have been widely studied using the ERP technique, a precise description of the time course of brain activity during encoding and retrieval is still required. Here, we used this technique and principal component analysis to assess the time course of brain activity during encoding and retrieval in a delayed match to sample task. We also investigated the effects of memory load and duration of the maintenance period on ERP activity. Brain activity was similar during information encoding and retrieval and comprised six temporal factors, which closely matched the latency and scalp distribution of some ERP components: P1, N1, P2, N2, P300 and a slow wave. Changes in memory load modulated task performance and yielded variations in frontal lobe activation. Moreover, the P300 amplitude was smaller in the high than in the low load condition during encoding and retrieval. Conversely, the slow wave amplitude was higher in the high than in the low load condition during encoding, and the same was true for the N2 amplitude during retrieval. Thus, during encoding, memory load appears to modulate the processing resources for context updating and post-categorization processes, and during retrieval it modulates resources for stimulus classification and context updating. Besides, despite the lack of differences in task performance related to duration of the maintenance period, larger N2 amplitude and stronger activation of the left temporal lobe after long than after short maintenance periods were found during information retrieval. Thus, results regarding the duration of maintenance period were complex, and future work is required to test the time-based decay

  19. A study of cognitive loading in dual-coding theory.

    Science.gov (United States)

    Ishi, H; Yamauchi, H

    1994-08-01

    15 university students were engaged in a task of recalling sentences with and without figures. Analysis of the number recalled indicated that cognitive loading for sentences with figures was more effective than for recall of sentences without figures.

  20. Load reduction test method of similarity theory and BP neural networks of large cranes

    Science.gov (United States)

    Yang, Ruigang; Duan, Zhibin; Lu, Yi; Wang, Lei; Xu, Gening

    2016-01-01

    Static load tests are an important means of supervising and detecting a crane's lift capacity. Due to space restrictions, however, there are difficulties and potential danger when testing large bridge cranes. To solve the loading problems of large-tonnage cranes during testing, an equivalency test is proposed based on the similarity theory and BP neural networks. The maximum stress and displacement of a large bridge crane is tested in small loads, combined with the training neural network of a similar structure crane through stress and displacement data which is collected by a physics simulation progressively loaded to a static load test load within the material scope of work. The maximum stress and displacement of a crane under a static load test load can be predicted through the relationship of stress, displacement, and load. By measuring the stress and displacement of small tonnage weights, the stress and displacement of large loads can be predicted, such as the maximum load capacity, which is 1.25 times the rated capacity. Experimental study shows that the load reduction test method can reflect the lift capacity of large bridge cranes. The load shedding predictive analysis for Sanxia 1200 t bridge crane test data indicates that when the load is 1.25 times the rated lifting capacity, the predicted displacement and actual displacement error is zero. The method solves the problem that lifting capacities are difficult to obtain and testing accidents are easily possible when 1.25 times related weight loads are tested for large tonnage cranes.

  1. Consolidation Theory for a Stone Column Composite Foundation under Multistage Loading

    OpenAIRE

    Huang, Shenggen; Feng, Yingtao; Liu, Hao; Wu, Wenbing; Mei, Guoxiong

    2016-01-01

    The consolidation theories considering instant load cannot fully reveal the consolidation mechanism of a stone column composite foundation used in the expressway embankments due to the time effect of loading; that is, the expressway embankments are often constructed in several stages for a long time. Meanwhile, owing to the special property that the pile-soil stress ratio is larger than 1, the consolidation theory for sand drain well foundation cannot be used directly in the consolidation ana...

  2. Commentary: Should Gender Differences Be Included in the Evolutionary Upgrade to Cognitive Load Theory?

    Science.gov (United States)

    Bevilacqua, Andy

    2017-01-01

    Recent upgrades to cognitive load theory suggest that evolutionary processes have shaped the way that working memory processes cultural and social information. According to evolutionarily educational psychologists, some forms of information are processed with lower working memory loads than other forms. The former are evolutionarily salient and…

  3. The evolution of cognitive load theory and its application to medical education

    NARCIS (Netherlands)

    Leppink, Jimmie; van den Heuvel, Angelique

    Cognitive Load Theory (CLT) has started to find more applications in medical education research. Unfortunately, misconceptions such as lower cognitive load always being beneficial to learning and the continued use of dated concepts and methods can result in improper applications of CLT principles in

  4. Research on Cognitive Load Theory and its Design Implications for E-Learning

    NARCIS (Netherlands)

    Van Merriënboer, Jeroen; Ayres, Paul

    2007-01-01

    This introduction to the special issue provides a context for the contributing articles. For readers who are not familiar with Cognitive Load Theory (CLT), it provides a very brief description of assumptions regarding memory systems and learning processes, different types of cognitive load

  5. Cognitive load theory, educational research, and instructional design; some food for thought

    NARCIS (Netherlands)

    de Jong, Anthonius J.M.

    2010-01-01

    Cognitive load is a theoretical notion with an increasingly central role in the educational research literature. The basic idea of cognitive load theory is that cognitive capacity in working memory is limited, so that if a learning task requires too much capacity, learning will be hampered. The

  6. Cognitive Load Theory and Complex Learning: Recent Developments and Future Directions

    NARCIS (Netherlands)

    Van Merriënboer, Jeroen; Sweller, J.

    2007-01-01

    Traditionally, Cognitive Load Theory (CLT) has focused on instructional methods to decrease extraneous cognitive load so that available cognitive resources can be fully devoted to learning. This article strengthens the cognitive base of CLT by linking cognitive processes to the processes used by

  7. Student Teacher Challenges: Using the Cognitive Load Theory as an Explanatory Lens

    Science.gov (United States)

    Moos, Daniel C.; Pitton, Debra

    2014-01-01

    Cognitive load theory (CLT) can explain the challenges faced by student teachers. This study, guided by the CLT, included 26 pre-service teachers. Participants completed a cognitive load self-report questionnaire and were interviewed at two points during their student teaching. Results revealed that student teachers decreased mental effort related…

  8. Practising what we preach: using cognitive load theory for workshop design and evaluation.

    Science.gov (United States)

    Naismith, Laura M; Haji, Faizal A; Sibbald, Matthew; Cheung, Jeffrey J H; Tavares, Walter; Cavalcanti, Rodrigo B

    2015-12-01

    Theory-based instructional design is a top priority in medical education. The goal of this Show and Tell article is to present our theory-driven approach to the design of instruction for clinical educators. We adopted cognitive load theory as a framework to design and evaluate a series of professional development workshops that were delivered at local, national and international academic conferences in 2014. We used two rating scales to measure participants' cognitive load. Participants also provided narrative comments as to how the workshops could be improved. Cognitive load ratings from 59 participants suggested that the workshop design optimized learning by managing complexity for different levels of learners (intrinsic load), stimulating cognitive processing for long-term memory storage (germane load), and minimizing irrelevant distracters (extraneous load). Narrative comments could also be classified as representing intrinsic, extraneous, or germane load, which provided specific directions for ongoing quality improvement. These results demonstrate that a cognitive load theory approach to workshop design and evaluation is feasible and useful in the context of medical education.

  9. Cognitive Load Theory, Educational Research, and Instructional Design: Some Food for Thought

    Science.gov (United States)

    de Jong, Ton

    2010-01-01

    Cognitive load is a theoretical notion with an increasingly central role in the educational research literature. The basic idea of cognitive load theory is that cognitive capacity in working memory is limited, so that if a learning task requires too much capacity, learning will be hampered. The recommended remedy is to design instructional systems…

  10. Varieties of perceptual learning.

    Science.gov (United States)

    Mackintosh, N J

    2009-05-01

    Although most studies of perceptual learning in human participants have concentrated on the changes in perception assumed to be occurring, studies of nonhuman animals necessarily measure discrimination learning and generalization and remain agnostic on the question of whether changes in behavior reflect changes in perception. On the other hand, animal studies do make it easier to draw a distinction between supervised and unsupervised learning. Differential reinforcement will surely teach animals to attend to some features of a stimulus array rather than to others. But it is an open question as to whether such changes in attention underlie the enhanced discrimination seen after unreinforced exposure to such an array. I argue that most instances of unsupervised perceptual learning observed in animals (and at least some in human animals) are better explained by appeal to well-established principles and phenomena of associative learning theory: excitatory and inhibitory associations between stimulus elements, latent inhibition, and habituation.

  11. Pembelajaran Berbantuan Multimedia Berdasarkan Cognitive Load Theory Pada Pelajaran Matematika SD

    OpenAIRE

    Kurniawati, Rissa Prima

    2014-01-01

    Multimedia is media that combine two or more elements are composed of text, graphics, images, photographs, audio, video, and animation are integrated. In multimedia-assisted learning, students are given the opportunity to learn not only of learning resources such as teachers, but give the opportunity to students to develop better cognitive, creative, and innovative. Cognitive Load Theory is a theory that was introduced as a teaching theory based on the knowledge of human cognitive architectur...

  12. PEMBELAJARAN BERBANTUAN MULTIMEDIA BERDASARKAN COGNITIVE LOAD THEORY PADA PELAJARAN MATEMATIKA SD

    OpenAIRE

    Rissa Prima Kurniawati

    2016-01-01

    Multimedia is media that combine two or more elements are composed of text, graphics, images, photographs, audio, video, and animation are integrated. In multimedia-assisted learning, students are given the opportunity to learn not only of learning resources such as teachers, but give the opportunity to students to develop better cognitive, creative, and innovative. Cognitive Load Theory is a theory that was introduced as a teaching theory based on the knowledge of human cognitive architectur...

  13. Comparison of Theory and Experiment on Aeroacoustic Loads and Deflections

    Science.gov (United States)

    Campos, L. M. B. C.; Bourgine, A.; Bonomi, B.

    1999-01-01

    The correlation of acoustic pressure loads induced by a turbulent wake on a nearby structural panel is considered: this problem is relevant to the acoustic fatigue of aircraft, rocket and satellite structures. Both the correlation of acoustic pressure loads and the panel deflections, were measured in an 8-m diameter transonic wind tunnel. Using the measured correlation of acoustic pressures, as an input to a finite-element aeroelastic code, the panel response was reproduced. The latter was also satisfactorily reproduced, using again the aeroelastic code, with input given by a theoretical formula for the correlation of acoustic pressures; the derivation of this formula, and the semi-empirical parameters which appear in it, are included in this paper. The comparison of acoustic responses in aeroacoustic wind tunnels (AWT) and progressive wave tubes (PWT) shows that much work needs to be done to bridge that gap; this is important since the PWT is the standard test means, whereas the AWT is more representative of real flight conditions but also more demanding in resources. Since this may be the first instance of successful modelling of acoustic fatigue, it may be appropriate to list briefly the essential ``positive'' features and associated physical phenomena: (i) a standard aeroelastic structural code can predict acoustic fatigue, provided that the correlation of pressure loads be adequately specified; (ii) the correlation of pressure loads is determined by the interference of acoustic waves, which depends on the exact evaluation of multiple scattering integrals, involving the statistics of random phase shifts; (iii) for the relatively low frequencies (one to a few hundred Hz) of aeroacoustic fatigue, the main cause of random phase effects is scattering by irregular wakes, which are thin on wavelength scale, and appear as partially reflecting rough interfaces. It may also be appropriate to mention some of the ``negative'' features, to which may be attached illusory

  14. Using Multiple Ways to Investigate Cognitive Load Theory in the Context of Physics Instruction

    Science.gov (United States)

    Zu, Tianlong

    Cognitive load theory (CLT) (Sweller 1988, 1998, 2010) provides us a guiding framework for designing instructional materials. CLT differentiates three subtypes of cognitive load: intrinsic, extraneous, and germane cognitive load. The three cognitive loads are theorized based on the number of simultaneously processed elements in working memory. Intrinsic cognitive load depends upon the number of interacting elements in the instructional material that are related to the learning objective. Extraneous cognitive load is the mental resources allocated to processing unnecessary information which does not contribute to learning as caused by non- optimal instructional procedure. It is determined by the number of interacting elements which are not related to learning goal. Both intrinsic and extraneous load vary according to prior knowledge of learners. Germane cognitive load is indirectly related to interacting elements. It represents the cognitive resources deployed for processing intrinsic load, chunking information and constructing and automating schema. Germane cognitive load is related to level of motivation of the learner. Given this triarchic model of cognitive load and their different roles in learning activities, different learning outcomes can be expected depending upon the characteristics of the educational materials, learner characteristics, and instructional setting. In three experiments, we investigated cognitive load theory following different approaches. Given the triarchic nature of cognitive load construct, it is critical to find non- intrusive ways to measure cognitive load. In study one, we replicated and extended a previous landmark study to investigate the use of eye movements related metrics to measure the three kinds of cognitive load independently. We also collected working memory capacity of students using a cognitive operation-span task. Two of the three types of cognitive load (intrinsic and extraneous) were directly manipulated, and the third

  15. Opposite effects of capacity load and resolution load on distractor processing.

    Science.gov (United States)

    Zhang, Weiwei; Luck, Steven J

    2015-02-01

    According to the load theory of attention, an increased perceptual load reduces distractor processing whereas an increased working memory load facilitates distractor processing. Here we raise the possibility that the critical distinction may instead be between an emphasis on resolution and an emphasis on capacity. That is, perceptual load manipulations typically emphasize resolution (fine-grained discriminations), whereas working memory load manipulations typically emphasize capacity (simultaneous processing of multiple relevant stimuli). To test the plausibility of this hypothesis, we used a visual working memory task that emphasized either the number of items to be stored (capacity load, retaining 2 vs. 4 colors) or the precision of the representations (resolution load, detecting small vs. large color changes). We found that an increased capacity load led to increased flanker interference (a measure of distractor processing), whereas an increased resolution load led to reduced flanker interference. These opposite effects of capacity load and resolution load on distractor processing mirror the previously described opposite effects of perceptual load and working memory load.

  16. Constraints on Perceptual Learning: Objects and Dimensions.

    Science.gov (United States)

    Bedford, Felice L.

    1995-01-01

    Addresses two questions that may be unique to perceptual learning: What are the circumstances that produce learning? and What is the content of learning? Suggests a critical principle for each question. Provides a discussion of perceptual learning theory, how learning occurs, and what gets learned. Includes a 121-item bibliography. (DR)

  17. Attentional load and attentional boost: A review of data and theory

    Directory of Open Access Journals (Sweden)

    Khena M Swallow

    2013-05-01

    Full Text Available Both perceptual and cognitive processes are limited in capacity. As a result, attention is selective, prioritizing items and tasks that are important for adaptive behavior. However, a number of recent behavioral and neuroimaging studies suggest that, at least under some circumstances, increasing attention to one task can enhance performance in a second task (e.g., the attentional boost effect. Here we review these findings and suggest a new theoretical framework, the dual-task interaction model, that integrates these findings with current views of attentional selection. To reconcile the attentional boost effect with the effects of attentional load, we suggest that temporal selection results in a temporally specific enhancement across modalities, tasks, and spatial locations. Moreover, the effects of temporal selection may be best observed when the attentional system is optimally tuned to the temporal dynamics of incoming stimuli. Several avenues of research motivated by the dual-task interaction model are then discussed.

  18. Attentional load and attentional boost: a review of data and theory.

    Science.gov (United States)

    Swallow, Khena M; Jiang, Yuhong V

    2013-01-01

    Both perceptual and cognitive processes are limited in capacity. As a result, attention is selective, prioritizing items and tasks that are important for adaptive behavior. However, a number of recent behavioral and neuroimaging studies suggest that, at least under some circumstances, increasing attention to one task can enhance performance in a second task (e.g., the attentional boost effect). Here we review these findings and suggest a new theoretical framework, the dual-task interaction model, that integrates these findings with current views of attentional selection. To reconcile the attentional boost effect with the effects of attentional load, we suggest that temporal selection results in a temporally specific enhancement across modalities, tasks, and spatial locations. Moreover, the effects of temporal selection may be best observed when the attentional system is optimally tuned to the temporal dynamics of incoming stimuli. Several avenues of research motivated by the dual-task interaction model are then discussed.

  19. Attentional Load and Attentional Boost: A Review of Data and Theory

    Science.gov (United States)

    Swallow, Khena M.; Jiang, Yuhong V.

    2013-01-01

    Both perceptual and cognitive processes are limited in capacity. As a result, attention is selective, prioritizing items and tasks that are important for adaptive behavior. However, a number of recent behavioral and neuroimaging studies suggest that, at least under some circumstances, increasing attention to one task can enhance performance in a second task (e.g., the attentional boost effect). Here we review these findings and suggest a new theoretical framework, the dual-task interaction model, that integrates these findings with current views of attentional selection. To reconcile the attentional boost effect with the effects of attentional load, we suggest that temporal selection results in a temporally specific enhancement across modalities, tasks, and spatial locations. Moreover, the effects of temporal selection may be best observed when the attentional system is optimally tuned to the temporal dynamics of incoming stimuli. Several avenues of research motivated by the dual-task interaction model are then discussed. PMID:23730294

  20. COGNITIVE LOAD THEORY Written by John SWELLER, Paul AYRES, and Slava KALYUGA,

    Directory of Open Access Journals (Sweden)

    Reviewed by Kadir KOZAN

    2013-04-01

    Full Text Available Cognitive load theory (2011 by John Sweller, Paul Ayres, and Slava Kalyuga presents the state-of-the art form of cognitive load theory (CLT including instructional guidelines produced by the theory so far. The book achieves this in a precise, detailed and well-organized manner thereby being very informative from the very beginning to the very end. For instance, even the preface provides an ample amount of information about CLT after stating the main premise of this theory: “Without knowledge of human cognitive processes, instructional design is blind.” (p. v. As stated in the book, CLT is that sort of a theory that informs instructional design from a cognitive perspective or on the basis of how human cognition works.

  1. Elevated temperature inelastic analysis of metallic media under time varying loads using state variable theories

    International Nuclear Information System (INIS)

    Kumar, V.; Mukherjee, S.

    1977-01-01

    In the present paper a general time-dependent inelastic analysis procedure for three-dimensional bodies subjected to arbitrary time varying mechanical and thermal loads using these state variable theories is presented. For the purpose of illustrations, the problems of hollow spheres, cylinders and solid circular shafts subjected to various combinations of internal and external pressures, axial force (or constraint) and torque are analyzed using the proposed solution procedure. Various cyclic thermal and mechanical loading histories with rectangular or sawtooth type waves with or without hold-time are considered. Numerical results for these geometrical shapes for various such loading histories are presented using Hart's theory (Journal of Engineering Materials and Technology 1976). The calculations are performed for nickel in the temperature range of 25 0 C to 400 0 C. For integrating forward in time, a method of solving a stiff system of ordinary differential equations is employed which corrects the step size and order of the method automatically. The limit loads for hollow spheres and cylinders are calculated using the proposed method and Hart's theory, and comparisons are made against the known theoretical results. The numerical results for other loading histories are discussed in the context of Hart's state variable type constitutive relations. The significance of phenomena such as strain rate sensitivity, Bauschinger's effect, crep recovery, history dependence and material softening with regard to these multiaxial problems are discussed in the context of Hart's theory

  2. The persistence of erroneous familiarity in an epileptic male : Challenging perceptual theories of déjà vu activation

    OpenAIRE

    O'Connor, Akira Robert; Moulin, Christopher J. A.

    2008-01-01

    We report the case of a 39-year-old, temporal lobe epileptic male, MH. Prior to complex partial seizure, experienced up to three times a day, MH often experiences an aura experienced as a persistent sensation of deja vu. Data-driven theories of deja vu formation suggest that partial familiarity for the perceived stimulus is responsible for the sensation. Consequently, diverting attention away from this stimulus should cause the sensation to dissipate. MH, whose sensations of deja vu persist l...

  3. Assessing Cognitive Load Theory to Improve Student Learning for Mechanical Engineers

    Science.gov (United States)

    Impelluso, Thomas J.

    2009-01-01

    A computer programming class for students of mechanical engineering was redesigned and assessed: Cognitive Load Theory was used to redesign the content; online technologies were used to redesign the delivery. Student learning improved and the dropout rate was reduced. This article reports on both attitudinal and objective assessment: comparing…

  4. Cognitive Load Theory: A Broader View on the Role of Memory in Learning and Education

    Science.gov (United States)

    Paas, Fred; Ayres, Paul

    2014-01-01

    According to cognitive load theory (CLT), the limitations of working memory (WM) in the learning of new tasks together with its ability to cooperate with an unlimited long-term memory (LTM) for familiar tasks enable human beings to deal effectively with complex problems and acquire highly complex knowledge and skills. With regard to WM, CLT has…

  5. Cognitive Load Theory and the Effects of Transient Information on the Modality Effect

    Science.gov (United States)

    Leahy, Wayne; Sweller, John

    2016-01-01

    Based on cognitive load theory and the "transient information effect," this paper investigated the "modality effect" while interpreting a contour map. The length and complexity of auditory and visual text instructions were manipulated. Experiment 1 indicated that longer audio text information within a presentation was inferior…

  6. Example-Based Learning in Heuristic Domains: A Cognitive Load Theory Account

    Science.gov (United States)

    Renkl, Alexander; Hilbert, Tatjana; Schworm, Silke

    2009-01-01

    One classical instructional effect of cognitive load theory (CLT) is the worked-example effect. Although the vast majority of studies have focused on well-structured and algorithmic sub-domains of mathematics or physics, more recent studies have also analyzed learning with examples from complex domains in which only heuristic solution strategies…

  7. Semantic Representations in 3D Perceptual Space

    Directory of Open Access Journals (Sweden)

    Suncica Zdravkovic

    2011-05-01

    Full Text Available Barsalou's (1999 perceptual theory of knowledge echoes the pre-20th century tradition of conceptualizing all knowledge as inherently perceptual. Hence conceptual space has an infinite number of dimensions and heavily relies on perceptual experience. Osgood's (1952 semantic differential technique was developed as a bridge between perception and semantics. We updated Osgood's methodology in order to investigate current issues in visual cognition by: (1 using a 2D rather than a 1D space to place the concepts, (2 having dimensions that were perceptual while the targets were conceptual, (3 coupling visual experience with another two perceptual domains (audition and touch, (4 analyzing the data using MDS (not factor analysis. In three experiments, subjects (N = 57 judged five concrete and five abstract words on seven bipolar scales in three perceptual modalities. The 2D space led to different patterns of response compared to the classic 1D space. MDS revealed that perceptual modalities are not equally informative for mapping word-meaning distances (Mantel min = −.23; Mantel max = .88. There was no reliable differences due to test administration modality (paper vs. computer, nor scale orientation. The present findings are consistent with multidimensionality of conceptual space, a perceptual basis for knowledge, and dynamic characteristics of concepts discussed in contemporary theories.

  8. Consolidation Theory for a Stone Column Composite Foundation under Multistage Loading

    Directory of Open Access Journals (Sweden)

    Shenggen Huang

    2016-01-01

    Full Text Available The consolidation theories considering instant load cannot fully reveal the consolidation mechanism of a stone column composite foundation used in the expressway embankments due to the time effect of loading; that is, the expressway embankments are often constructed in several stages for a long time. Meanwhile, owing to the special property that the pile-soil stress ratio is larger than 1, the consolidation theory for sand drain well foundation cannot be used directly in the consolidation analysis of stone column composite foundation. Based on the principle that the vertical load applied on the composite foundation is shared by the stone column and the surrounding soil, the governing solutions for the stone column composite foundation under a multistage load are established. By virtue of the separation of variables, the corresponding solutions of degree of consolidation for loading stage and maintaining load stage are derived separately. According to the Carrillo theorem, the solution for the average total degree of consolidation of entire composite foundation is also obtained. Finally, the reasonableness of the present solution has been verified by comparing the consolidation curve calculated by the present solution with that measured by site test.

  9. In Respect to the Cognitive Load Theory: Adjusting Instructional Guidance with Student Expertise.

    Science.gov (United States)

    Schilling, Jim

    2017-01-01

    The amount of guidance supplied by educators to students in allied health programs is a factor in student learning. According to the cognitive load theory of learning, without adequate instructional support, novice learners will be overwhelmed and unable to store information, while unnecessary guidance supplied to advanced students will cause extraneous cognitive load on the working memory system. Adjusting instructional guidance for students according to their level of expertise to minimize extraneous cognitive load and optimize working memory storage capacity will enhance learning effectiveness. Novice students presented with complex subject matter require significant guidance during the initial stages, using strategies such as worked examples. As students comprehend information, instructional guidance needs to gradually fade to avoid elevated extraneous cognitive load from the expertise reversal effect. An instructional strategy that utilizes a systemic (fixed) or adjustable (adaptive) tapering of guidance to students in allied health programs depending on their expertise will optimize learning capability.

  10. Cognitive Load Theory: implications for medical education: AMEE Guide No. 86.

    Science.gov (United States)

    Young, John Q; Van Merrienboer, Jeroen; Durning, Steve; Ten Cate, Olle

    2014-05-01

    Cognitive Load Theory (CLT) builds upon established models of human memory that include the subsystems of sensory, working and long-term memory. Working memory (WM) can only process a limited number of information elements at any given time. This constraint creates a "bottleneck" for learning. CLT identifies three types of cognitive load that impact WM: intrinsic load (associated with performing essential aspects of the task), extraneous load (associated with non-essential aspects of the task) and germane load (associated with the deliberate use of cognitive strategies that facilitate learning). When the cognitive load associated with a task exceeds the learner's WM capacity, performance and learning is impaired. To facilitate learning, CLT researchers have developed instructional techniques that decrease extraneous load (e.g. worked examples), titrate intrinsic load to the developmental stage of the learner (e.g. simplify task without decontextualizing) and ensure that unused WM capacity is dedicated to germane load, i.e. cognitive learning strategies. A number of instructional techniques have been empirically tested. As learners' progress, curricula must also attend to the expertise-reversal effect. Instructional techniques that facilitate learning among early learners may not help and may even interfere with learning among more advanced learners. CLT has particular relevance to medical education because many of the professional activities to be learned require the simultaneous integration of multiple and varied sets of knowledge, skills and behaviors at a specific time and place. These activities possess high "element interactivity" and therefore impose a cognitive load that may surpass the WM capacity of the learner. Applications to various medical education settings (classroom, workplace and self-directed learning) are explored.

  11. Cognitive Load and Self-Determination Theories Applied to E-Learning : Impact on Students' Participation and Academic Performance

    NARCIS (Netherlands)

    de Araujo Guerra Grangeia, Tiago; de Jorge, Bruno; Franci, Daniel; Martins Santos, Thiago; Vellutini Setubal, Maria Silvia; Schweller, Marcelo; de Carvalho-Filho, Marco Antonio

    2016-01-01

    BACKGROUND: Emergency clerkships expose students to a stressful environment that require multiple tasks, which may have a direct impact on cognitive load and motivation for learning. To address this challenge, Cognitive Load Theory and Self Determination Theory provided the conceptual frameworks to

  12. Development of a VVER-1000 core loading pattern optimization program based on perturbation theory

    International Nuclear Information System (INIS)

    Hosseini, Mohammad; Vosoughi, Naser

    2012-01-01

    Highlights: ► We use perturbation theory to find an optimum fuel loading pattern in a VVER-1000. ► We provide a software for in-core fuel management optimization. ► We consider two objectives for our method (perturbation theory). ► We show that perturbation theory method is very fast and accurate for optimization. - Abstract: In-core nuclear fuel management is one of the most important concerns in the design of nuclear reactors. Two main goals in core fuel loading pattern design optimization are maximizing the core effective multiplication factor in order to extract the maximum energy, and keeping the local power peaking factor lower than a predetermined value to maintain the fuel integrity. Because of the numerous possible patterns of fuel assemblies in the reactor core, finding the best configuration is so important and challenging. Different techniques for optimization of fuel loading pattern in the reactor core have been introduced by now. In this study, a software is programmed in C language to find an order of the fuel loading pattern of a VVER-1000 reactor core using the perturbation theory. Our optimization method is based on minimizing the radial power peaking factor. The optimization process launches by considering an initial loading pattern and the specifications of the fuel assemblies which are given as the input of the software. The results on a typical VVER-1000 reactor reveal that the method could reach to a pattern with an allowed radial power peaking factor and increases the cycle length 1.1 days, as well.

  13. Implementation and Assessment of Cognitive Load Theory (CLT) Based Questions in an Electronic Homework and Testing System

    Science.gov (United States)

    Behmke, Derek A.; Atwood, Charles H.

    2013-01-01

    To a first approximation, human memory is divided into two parts, short-term and long-term. Cognitive Load Theory (CLT) attempts to minimize the short-term memory load while maximizing the memory available for transferring knowledge from short-term to long-term memory. According to CLT there are three types of load, intrinsic, extraneous, and…

  14. Improving the Quality of Online Discussion: The Effects of Strategies Designed Based on Cognitive Load Theory Principles

    Science.gov (United States)

    Darabi, Aubteen; Jin, Li

    2013-01-01

    This article focuses on heavy cognitive load as the reason for the lack of quality associated with conventional online discussion. Using the principles of cognitive load theory, four online discussion strategies were designed specifically aiming at reducing the discussants' cognitive load and thus enhancing the quality of their online discussion.…

  15. Maximized gust loads for a nonlinear airplane using matched filter theory and constrained optimization

    Science.gov (United States)

    Scott, Robert C.; Perry, Boyd, III; Pototzky, Anthony S.

    1991-01-01

    This paper describes and illustrates two matched-filter-theory based schemes for obtaining maximized and time-correlated gust-loads for a nonlinear airplane. The first scheme is computationally fast because it uses a simple one-dimensional search procedure to obtain its answers. The second scheme is computationally slow because it uses a more complex multidimensional search procedure to obtain its answers, but it consistently provides slightly higher maximum loads than the first scheme. Both schemes are illustrated with numerical examples involving a nonlinear control system.

  16. Preventing information overload: cognitive load theory as an instructional framework for teaching pharmacology.

    Science.gov (United States)

    Kaylor, Sara K

    2014-02-01

    Nursing students are challenged by content-laden curricula and learning environments that emphasize testing outcomes. Likewise, educators are challenged to support student-centered learning in a manner that encourages students to connect and act upon their personal motivations. This article describes the use of cognitive load theory (CLT) as an instructional design framework for an undergraduate pharmacology for nursing course. Guided by the principles of CLT, four instructional strategies were used in this course: (a) opening review activities, (b) providing students with lecture notes, (c) a "Top Five" prototype approach, and (d) deciphering "Need to Knows" from "Nice to Knows." Instructional style and strategies received positive student feedback and were found to promote a student-centered environment and active learning. On the basis of this feedback, cognitive load theory may be a successful and effective framework for undergraduate pharmacology and other nursing courses, thus assisting students and educators alike in overcoming obstacles imposed on learning environments. Copyright 2014, SLACK Incorporated.

  17. Stroop-like effects in a new-code learning task: A cognitive load theory perspective.

    Science.gov (United States)

    Hazan-Liran, Batel; Miller, Paul

    2017-09-01

    To determine whether and how learning is biased by competing task-irrelevant information that creates extraneous cognitive load, we assessed the efficiency of university students with a learning paradigm in two experiments. The paradigm asked participants to learn associations between eight words and eight digits. We manipulated congruity of the digits' ink colour with the words' semantics. In Experiment 1 word stimuli were colour words (e.g., blue, yellow) and in Experiment 2 colour-related word concepts (e.g., sky, banana). Marked benefits and costs on learning due to variation in extraneous cognitive load originating from processing task-irrelevant information were evident. Implications for cognitive load theory and schooling are discussed.

  18. Generalized perturbation theory error control within PWR core-loading pattern optimization

    International Nuclear Information System (INIS)

    Imbriani, J.S.; Turinsky, P.J.; Kropaczek, D.J.

    1995-01-01

    The fuel management optimization code FORMOSA-P has been developed to determine the family of near-optimum loading patterns for PWR reactors. The code couples the optimization technique of simulated annealing (SA) with a generalized perturbation theory (GPT) model for evaluating core physics characteristics. To ensure the accuracy of the GPT predictions, as well as to maximize the efficient of the SA search, a GPT error control method has been developed

  19. Unpacking the Complexity of Patient Handoffs Through the Lens of Cognitive Load Theory.

    Science.gov (United States)

    Young, John Q; Ten Cate, Olle; O'Sullivan, Patricia S; Irby, David M

    2016-01-01

    The transfer of a patient from one clinician to another is a high-risk event. Errors are common and lead to patient harm. More effective methods for learning how to give and receive sign-out is an important public health priority. Performing a handoff is a complex task. Trainees must simultaneously apply and integrate clinical, communication, and systems skills into one time-limited and highly constrained activity. The task demands can easily exceed the information-processing capacity of the trainee, resulting in impaired learning and performance. Appreciating the limits of working memory can help identify the challenges that instructional techniques and research must then address. Cognitive load theory (CLT) identifies three types of load that impact working memory: intrinsic (task-essential), extraneous (not essential to task), and germane (learning related). The authors generated a list of factors that affect a trainee's learning and performance of a handoff based on CLT. The list was revised based on feedback from experts in medical education and in handoffs. By consensus, the authors associated each factor with the type of cognitive load it primarily effects. The authors used this analysis to build a conceptual model of handoffs through the lens of CLT. The resulting conceptual model unpacks the complexity of handoffs and identifies testable hypotheses for educational research and instructional design. The model identifies features of a handoff that drive extraneous, intrinsic, and germane load for both the sender and the receiver. The model highlights the importance of reducing extraneous load, matching intrinsic load to the developmental stage of the learner and optimizing germane load. Specific CLT-informed instructional techniques for handoffs are explored. Intrinsic and germane load are especially important to address and include factors such as knowledge of the learner, number of patients, time constraints, clinical uncertainties, overall patient

  20. Sound as Affective Design Feature in Multimedia Learning--Benefits and Drawbacks from a Cognitive Load Theory Perspective

    Science.gov (United States)

    Königschulte, Anke

    2015-01-01

    The study presented in this paper investigates the potential effects of including non-speech audio such as sound effects into multimedia-based instruction taking into account Sweller's cognitive load theory (Sweller, 2005) and applied frameworks such as the cognitive theory of multimedia learning (Mayer, 2005) and the cognitive affective theory of…

  1. Relationship between social-cognitive and social-perceptual aspects of theory of mind and neurocognitive deficits, insight level and schizotypal traits in obsessive-compulsive disorder.

    Science.gov (United States)

    Mısır, Emre; Bora, Emre; Akdede, Berna Binnur

    2018-05-01

    The primary aim of the current study was to investigate different aspects of theory of mind (ToM), including social-cognitive (ToM-reasoning) and social-perceptual (ToM-decoding) in obsessive-compulsive disorder (OCD). We also aimed to investigate the relationship between ToM, neurocognition and a number of clinical variables including overvalued ideas, schizotypal personality traits, level of insight, and disease severity. Thirty-four patients who have been diagnosed with OCD according to DSM-IV and 30 healthy controls were included in the study. All participants were given a neuropsychological battery including tasks measuring ToM-reasoning, ToM-decoding and other neurocognitive functions. Schizotypal Personality Questionnaire (SPQ), Yale Brown Obsession and Compulsion Scale (YBOC-S) and Overvalued Ideas Scale (OVIS) were also administered to the participants. Patients with OCD showed significant deficits in both aspects of ToM. ToM performances of patients showed a significant positive correlation with neurocognitive functions. When controlled for general cognition factor, patient-control difference for ToM-reasoning (F = 3,917; p = 0,05), but not ToM-decoding, remained statistically significant. ToM-reasoning impairment of patients was significantly related to the severity of OCD symptoms and poor insight (p = 0,026 and p = 0,045, respectively). On the other hand, general cognitive factor (β = 0,778; t = 3,146; p = 0,04) was found to be the only significant predictor of ToM-reasoning in OCD patients in the multiple linear regression model. OCD is associated with ToM impairment, which is related to schizotypal traits, disease severity and poor insight, yet neurocognitive deficits also significantly contribute to this finding. However, ToM-reasoning impairment could be considered as a relatively distinct feature of OCD, which is partly separate from general cognitive deficits. Copyright © 2018. Published by Elsevier Inc.

  2. A novel reformulation of the Theory of Critical Distances to design notched metals against dynamic loading

    International Nuclear Information System (INIS)

    Yin, T.; Tyas, A.; Plekhov, O.; Terekhina, A.; Susmel, L.

    2015-01-01

    Highlights: • The proposed method is successful in estimating dynamic strength of metals. • The critical distance varies as the loading/strain/displacement rate increases. • The reference strength varies as the loading/strain/displacement rate increases. • This method is recommended to be used with safety factors larger than 1.25. - Abstract: In the present study the linear-elastic Theory of Critical Distances (TCD) is reformulated to make it suitable for predicting the strength of notched metallic materials subjected to dynamic loading. The accuracy and reliability of the proposed reformulation of the TCD was checked against a number of experimental results generated by testing, under different loading/strain rates, notched cylindrical samples of aluminium alloy 6063-T5, titanium alloy Ti–6Al–4V, aluminium alloy AlMg6, and an AlMn alloy. To further validate the proposed design method also different data sets taken from the literature were considered. Such an extensive validation exercise allowed us to prove that the proposed reformulation of the TCD is successful in predicting the dynamic strength of notched metallic materials, this approach proving to be capable of estimates falling within an error interval of ±20%. Such a high level of accuracy is certainly remarkable, especially in light of the fact that it was reached without the need for explicitly modelling the stress vs. strain dynamic behaviour of the investigated ductile metals

  3. Pupillary response to complex interdependent tasks: A cognitive-load theory perspective.

    Science.gov (United States)

    Mitra, Ritayan; McNeal, Karen S; Bondell, Howard D

    2017-10-01

    Pupil dilation is known to indicate cognitive load. In this study, we looked at the average pupillary responses of a cohort of 29 undergraduate students during graphical problem solving. Three questions were asked, based on the same graphical input. The questions were interdependent and comprised multiple steps. We propose a novel way of analyzing pupillometry data for such tasks on the basis of eye fixations, a commonly used eyetracking parameter. We found that pupil diameter increased during the solution process. However, pupil diameter did not always reflect the expected cognitive load. This result was studied within a cognitive-load theory model. Higher-performing students showed evidence of germane load and schema creation, indicating use of the interdependent nature of the tasks to inform their problem-solving process. However, lower-performing students did not recognize the interdependent nature of the tasks and solved each problem independently, which was expressed in a markedly different pupillary response pattern. We discuss the import of our findings for instructional design.

  4. Optimizing physicians' instruction of PACS through e-learning: cognitive load theory applied.

    Science.gov (United States)

    Devolder, P; Pynoo, B; Voet, T; Adang, L; Vercruysse, J; Duyck, P

    2009-03-01

    This article outlines the strategy used by our hospital to maximize the knowledge transfer to referring physicians on using a picture archiving and communication system (PACS). We developed an e-learning platform underpinned by the cognitive load theory (CLT) so that in depth knowledge of PACS' abilities becomes attainable regardless of the user's prior experience with computers. The application of the techniques proposed by CLT optimizes the learning of the new actions necessary to obtain and manipulate radiological images. The application of cognitive load reducing techniques is explained with several examples. We discuss the need to safeguard the physicians' main mental processes to keep the patient's interests in focus. A holistic adoption of CLT techniques both in teaching and in configuration of information systems could be adopted to attain this goal. An overview of the advantages of this instruction method is given both on the individual and organizational level.

  5. On the application of the dynamic plasticity theory for the treatment of reinforced concrete structures under transient loading

    International Nuclear Information System (INIS)

    Ammann, W.

    1983-01-01

    After a short introduction of the theory of dynamic plasticity, the possible applications of this theory on reinforced concrete structures under transient loading are discussed. Estimates can be obtained by relations giving lower and upper limits for dynamically loaded supporting beams. A procedure similar for the mode approximation method is described for the calculation of beams after a sudden failure of a support. (orig.) [de

  6. Collapse models and perceptual processes

    International Nuclear Information System (INIS)

    Ghirardi, Gian Carlo; Romano, Raffaele

    2014-01-01

    Theories including a collapse mechanism have been presented various years ago. They are based on a modification of standard quantum mechanics in which nonlinear and stochastic terms are added to the evolution equation. Their principal merits derive from the fact that they are mathematically precise schemes accounting, on the basis of a unique universal dynamical principle, both for the quantum behavior of microscopic systems as well as for the reduction associated to measurement processes and for the classical behavior of macroscopic objects. Since such theories qualify themselves not as new interpretations but as modifications of the standard theory they can be, in principle, tested against quantum mechanics. Recently, various investigations identifying possible crucial test have been discussed. In spite of the extreme difficulty to perform such tests it seems that recent technological developments allow at least to put precise limits on the parameters characterizing the modifications of the evolution equation. Here we will simply mention some of the recent investigations in this direction, while we will mainly concentrate our attention to the way in which collapse theories account for definite perceptual process. The differences between the case of reductions induced by perceptions and those related to measurement procedures by means of standard macroscopic devices will be discussed. On this basis, we suggest a precise experimental test of collapse theories involving conscious observers. We make plausible, by discussing in detail a toy model, that the modified dynamics can give rise to quite small but systematic errors in the visual perceptual process.

  7. Self-Instructional Module Based on Cognitive Load Theory: A Study on Information Retention among Trainee Teachers

    Science.gov (United States)

    Ong, Chiek Pin; Tasir, Zaidatun

    2015-01-01

    The aim of the research is to study the information retention among trainee teachers using a self-instructional printed module based on Cognitive Load Theory for learning spreadsheet software. Effective pedagogical considerations integrating the theoretical concepts related to cognitive load are reflected in the design and development of the…

  8. A large deformation theory of solids subject to electromagnetic loads and its application

    International Nuclear Information System (INIS)

    Nishiguchi, I.; Sasaki, M.

    1993-01-01

    A large deformation theory of deformable solids is proposed in which the interaction with electromagnetic fields is taken into account. Weak forms of the Maxwell's equations in a fixed reference configuration together with the balance of momentum constitute the governing equations for our theory. The weak forms of the Maxwell's equations in a reference configuration can be derived by the direct transformation from spatial weak forms. The results coincide with the weak forms obtained from the local expressions by Lax and Nelson though we made a distinction between the covariant and contravariant vector explicitly. For the deformable body subject to the electromagnetic fields, weak forms of the Ampere's law and/or the Faraday's law, when combined with the weak form of the balance of momentum, can serve as the governing equations of the theory. As is known, however, these equations are not sufficient to describe the response of a specific material due to a given loading. As for the momentum balance, we need the dependency of stress on the deformation and objective constitutive equations of hyperelasticity, hypoelasticity and inelasticity are available. Parallel to these, objective constitutive equations for the electromagnetism are discussed. As an application of the theory, linearized equations for quasi-static deformation under magnetic field is derived based on the vector potential formulation. (author)

  9. The Spatial Focus of Attention Is Controlled at Perceptual and Cognitive Levels

    Science.gov (United States)

    Caparos, Serge; Linnell, Karina J.

    2010-01-01

    Selective attention has been hypothesized to reduce distractor interference at both perceptual and postperceptual levels (Lavie, 2005), respectively, by focusing perceptual resources on the attended location and by blocking at postperceptual levels distractors that survive perceptual selection. This study measured the impact of load on these…

  10. Energy Dependent Divisible Load Theory for Wireless Sensor Network Workload Allocation

    Directory of Open Access Journals (Sweden)

    Haiyan Shi

    2012-01-01

    Full Text Available The wireless sensor network (WSN, consisting of a large number of microsensors with wireless communication abilities, has become an indispensable tool for use in monitoring and surveillance applications. Despite its advantages in deployment flexibility and fault tolerance, the WSN is vulnerable to failures due to the depletion of limited onboard battery energy. A major portion of energy consumption is caused by the transmission of sensed results to the master processor. The amount of energy used, in fact, is related to both the duration of sensing and data transmission. Hence, in order to extend the operation lifespan of the WSN, a proper allocation of sensing workload among the sensors is necessary. An assignment scheme is here formulated on the basis of the divisible load theory, namely, the energy dependent divisible load theory (EDDLT for sensing workload allocations. In particular, the amount of residual energies onboard sensors are considered while deciding the workload assigned to each sensor. Sensors with smaller amount of residual energy are assigned lighter workloads, thus, allowing for a reduced energy consumption and the sensor lifespan is extended. Simulation studies are conducted and results have illustrated the effectiveness of the proposed workload allocation method.

  11. Simplified Theory of Plastic Zones for cyclic loading and multilinear hardening

    International Nuclear Information System (INIS)

    Hübel, Hartwig

    2015-01-01

    The Simplified Theory of Plastic Zones (STPZ) is a direct method based on Zarka's method, primarily developed to estimate post-shakedown quantities of structures under cyclic loading, avoiding incremental analyses through a load histogram. In a different paper the STPZ has previously been shown to provide excellent estimates of the elastic–plastic strain ranges in the state of plastic shakedown as required for fatigue analyses. In the present paper, it is described how the STPZ can be used to predict the strains accumulated through a number of loading cycles due to a ratcheting mechanism, until either elastic or plastic shakedown is achieved, so that strain limits can be satisfied. Thus, a consistent means of estimating both, strain ranges and accumulated strains is provided for structural integrity assessment as required by pressure vessel codes. The computational costs involved typically consist of few linear elastic analyses and some local calculations. Multilinear kinematic hardening and temperature dependent yield stresses are accounted for. The quality of the results and the computational burden involved are demonstrated through four examples. - Highlights: • A method is provided to estimate accumulated elastic–plastic strains. • A consistent method is provided to estimate elastic–plastic strain ranges. • Effect of multilinear kinematic hardening is captured. • Temperature dependent material properties are accounted for. • Few linear elastic analyses required

  12. Perceptual Robust Design

    DEFF Research Database (Denmark)

    Pedersen, Søren Nygaard

    The research presented in this PhD thesis has focused on a perceptual approach to robust design. The results of the research and the original contribution to knowledge is a preliminary framework for understanding, positioning, and applying perceptual robust design. Product quality is a topic...... been presented. Therefore, this study set out to contribute to the understanding and application of perceptual robust design. To achieve this, a state-of-the-art and current practice review was performed. From the review two main research problems were identified. Firstly, a lack of tools...... for perceptual robustness was found to overlap with the optimum for functional robustness and at most approximately 2.2% out of the 14.74% could be ascribed solely to the perceptual robustness optimisation. In conclusion, the thesis have offered a new perspective on robust design by merging robust design...

  13. Failure mechanism and coupled static-dynamic loading theory in deep hard rock mining: A review

    Directory of Open Access Journals (Sweden)

    Xibing Li

    2017-08-01

    Full Text Available Rock failure phenomena, such as rockburst, slabbing (or spalling and zonal disintegration, related to deep underground excavation of hard rocks are frequently reported and pose a great threat to deep mining. Currently, the explanation for these failure phenomena using existing dynamic or static rock mechanics theory is not straightforward. In this study, new theory and testing method for deep underground rock mass under coupled static-dynamic loading are introduced. Two types of coupled loading modes, i.e. “critical static stress + slight disturbance” and “elastic static stress + impact disturbance”, are proposed, and associated test devices are developed. Rockburst phenomena of hard rocks under coupled static-dynamic loading are successfully reproduced in the laboratory, and the rockburst mechanism and related criteria are demonstrated. The results of true triaxial unloading compression tests on granite and red sandstone indicate that the unloading can induce slabbing when the confining pressure exceeds a certain threshold, and the slabbing failure strength is lower than the shear failure strength according to the conventional Mohr-Column criterion. Numerical results indicate that the rock unloading failure response under different in situ stresses and unloading rates can be characterized by an equivalent strain energy density. In addition, we present a new microseismic source location method without premeasuring the sound wave velocity in rock mass, which can efficiently and accurately locate the rock failure in hard rock mines. Also, a new idea for deep hard rock mining using a non-explosive continuous mining method is briefly introduced.

  14. Speed maintenance under cognitive load - Implications for theories of driver behaviour.

    Science.gov (United States)

    Lewis-Evans, Ben; de Waard, Dick; Brookhuis, Karel A

    2011-07-01

    No theory of driver behaviour has yet managed to achieve widespread acceptance and use in the field of Traffic Psychology, partly due to the difficulty in testing many of the theories. However, one class of theories, the motivational theories, can be usefully split into two groups and the differences between them can then be examined. One group posits the constant monitoring and targeting of a certain subjective variable, often risk, as the controlling factor in driving. The other group however states that subjective variables such as risk are only relevant once a certain threshold has been passed. In this study we aimed to examine this difference by manipulating both speed of travel and the amount of cognitive load participants were under. Participants were asked to initially drive at their preferred speed for 1min in a driving simulator. Participant's speed was then automatically increased or decreased by 10, 20 30km/h or left unchanged. Participants were then required to maintain the new speed for 1min. After this 1min the speed was again automatically changed and had to be maintained for one more minute, but this time participants also carried out a secondary mental arithmetic task. Finally participants were asked to again drive for another 1min at their preferred speed. This procedure was repeated seven times, once for each speed manipulation; -30, -20, -10, +0, +10, +20 and +30km/h. After each 1min interval verbal ratings of task difficulty, effort, feeling of risk and the typicality of the speed were collected. The results show a threshold effect in ratings of task difficulty, effort and feeling of risk, with no significant difference given between the ratings during the baseline period and the experimentally decreased speed periods until after participant's preferred speed of travel had been exceeded. Furthermore, even when under cognitive load the threshold relationship was still apparent, if diminished. Finally it appears that when under cognitive load

  15. Electromyographical and Perceptual Responses to Different Resistance Intensities in a Squat Protocol: Does Performing Sets to Failure With Light Loads Produce the Same Activity?

    Science.gov (United States)

    Looney, David P; Kraemer, William J; Joseph, Michael F; Comstock, Brett A; Denegar, Craig R; Flanagan, Shawn D; Newton, Robert U; Szivak, Tunde K; DuPont, William H; Hooper, David R; Häkkinen, Keijo; Maresh, Carl M

    2016-03-01

    This investigation examined peak motor unit activity during sets that differed in resistance (50, 70, or 90% 1 repetition maximum [1RM]). Ten resistance-trained men (age, 23 ± 3 years; height, 187 ± 7 cm; body mass, 91.5 ± 6.9 kg; squat 1RM, 141 ± 28 kg) were assessed by electromyography (EMG) on the vastus lateralis and vastus medialis muscles in a randomized within-subject experiment consisting of 2 test visits: a drop-set day and a single-set day using only the 50% of 1RM intensity performed to failure. At the start of each day, subjects performed 2 submaximal repetition sets (50% 1RM × 10 repetitions and 70% 1RM × 7 repetitions). On the drop-set day, subjects performed 3 consecutive maximal repetition sets at 90%, 70%, and 50% 1RM to failure with no rest periods in between. On the single-set day, subjects performed a maximal repetition set at 50% 1RM to failure. Overall, the maximal repetition sets to failure at 50% and 70% 1RM resulted in higher peak EMG amplitude than during submaximal repetition sets with the same resistance. However, peak EMG amplitude was significantly (p ≤ 0.05) greater in the maximal 90% 1RM set than all other sets performed. When sets were performed to failure, ratings of perceived exertion (CR-10) did not differ over the intensity range of loads and suggests that perception is not capable of accurately detecting the actual amount of motor unit activation. The results of this investigation indicate that using higher external resistance is a more effective means of increasing motor unit activity than increasing the number of repetitions performed with lighter weights even when the end point is muscular failure. Accordingly, previous recommendations for the use of heavier loads during resistance training programs to stimulate the maximal development of strength and hypertrophy are further supported.

  16. Effects of neuromuscular fatigue on perceptual-cognitive skills between genders in the contribution to the knee joint loading during side-stepping tasks.

    Science.gov (United States)

    Khalid, Abdul Jabbar; Harris, Sujae Ian; Michael, Loke; Joseph, Hamill; Qu, Xingda

    2015-01-01

    This study investigated whether neuromuscular fatigue affects the neuromuscular control of an athlete within a sports context setting and whether these effects were more pronounced in the females. Lower limb joint kinetics of 6 male and 6 female inter-varsity soccer players performing side-stepping tasks in non-fatigue versus fatigue and anticipated versus unanticipated conditions were quantified using 10 Motion Analysis Corporation cameras and a Kistler(™) force platform. The Yo-Yo intermittent recovery Level 1 fatigue protocol was employed. Stance foot initial contact and peak forces, and peak joint knee moments of the lower limb were submitted to a 3-way mixed-model repeated measure ANOVA. The results suggested that males tend to elicit significantly higher knee joint loadings when fatigued. In addition, males elicited significantly higher peak proximal tibia anterior/posterior shear force, vertical ground reaction force at initial contact and peak internal rotational moments than females. These findings suggested that males were at greater overall injury risk than females, especially in the sagittal plane. Neuromuscular control-based training programmes/interventions that are designed to reduce the risk of the non-contact ACL injury need to be customised for the different genders.

  17. THE APPLICATION OF MASSING HANDLING THEORY FOR EVALUATION OF THE APPLICATION OF WHARVES AND LOADING FACILITIES IN THE MARITIME PORT

    Directory of Open Access Journals (Sweden)

    Zbigniew Matuszak

    2016-09-01

    Full Text Available This work presents the general characteristics of the port system. It defines sets and functions describing the structure and work of the port. Moreover, it characterizes foundations of the massive handling theory. It provides basic literature information about selected processes and models of the massive handling theory. On the example of a transportation company serving the loading on ships in the port of Szczecin, it shows the loading method. The material loading onto ships was the sodium water glass. There are observation results of operation times comprising the data available to determine parameters of the massive handling theory. Operations covered in the analysis include: the arrival of the ship at the port’s road, waiting for enter the port, passing through the fairway, waiting for loading, loading, determination of the cargo’s weight, preparation of documents and waiting for leaving the port. It presents critical remarks about possibilities of using the data obtained to describe loading cargo on a ship with the use of elements of the massive handling theory.

  18. Thinking about Seeing: perceptual sources of knowledge are encoded in the theory of mind brain regions of sighted and blind adults

    Science.gov (United States)

    Koster-Hale, Jorie; Bedny, Marina; Saxe, Rebecca

    2014-01-01

    Blind people's inferences about how other people see provide a window into fundamental questions about the human capacity to think about one another's thoughts. By working with blind individuals, we can ask both what kinds of representations people form about others’ minds, and how much these representations depend on the observer having had similar mental states themselves. Thinking about others’ mental states depends on a specific group of brain regions, including the right temporo-parietal junction (RTPJ). We investigated the representations of others’ mental states in these brain regions, using multivoxel pattern analyses (MVPA). We found that, first, in the RTPJ of sighted adults, the pattern of neural response distinguished the source of the mental state (did the protagonist see or hear something?) but not the valence (did the protagonist feel good or bad?). Second, these neural representations were preserved in congenitally blind adults. These results suggest that the temporo-parietal junction contains explicit, abstract representations of features of others’ mental states, including the perceptual source. The persistence of these representations in congenitally blind adults, who have no first-person experience with sight, provides evidence that these representations emerge even in the absence of first-person perceptual experiences. PMID:24960530

  19. Thinking about seeing: perceptual sources of knowledge are encoded in the theory of mind brain regions of sighted and blind adults.

    Science.gov (United States)

    Koster-Hale, Jorie; Bedny, Marina; Saxe, Rebecca

    2014-10-01

    Blind people's inferences about how other people see provide a window into fundamental questions about the human capacity to think about one another's thoughts. By working with blind individuals, we can ask both what kinds of representations people form about others' minds, and how much these representations depend on the observer having had similar mental states themselves. Thinking about others' mental states depends on a specific group of brain regions, including the right temporo-parietal junction (RTPJ). We investigated the representations of others' mental states in these brain regions, using multivoxel pattern analyses (MVPA). We found that, first, in the RTPJ of sighted adults, the pattern of neural response distinguished the source of the mental state (did the protagonist see or hear something?) but not the valence (did the protagonist feel good or bad?). Second, these neural representations were preserved in congenitally blind adults. These results suggest that the temporo-parietal junction contains explicit, abstract representations of features of others' mental states, including the perceptual source. The persistence of these representations in congenitally blind adults, who have no first-person experience with sight, provides evidence that these representations emerge even in the absence of relevant first-person perceptual experiences. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Mindstorms robots and the application of cognitive load theory in introductory programming

    Science.gov (United States)

    Mason, Raina; Cooper, Graham

    2013-12-01

    This paper reports on a series of introductory programming workshops, initially targeting female high school students, which utilised Lego Mindstorms robots. Cognitive load theory (CLT) was applied to the instructional design of the workshops, and a controlled experiment was also conducted investigating aspects of the interface. Results indicated that a truncated interface led to better learning by novice programmers as measured by test performance by participants, as well as enhanced shifts in self-efficacy and lowered perception of difficulty. There was also a transfer effect to another programming environment (Alice). It is argued that the results indicate that for novice programmers, the mere presence on-screen of additional (redundant) entities acts as a form of tacit distraction, thus impeding learning. The utility of CLT to analyse, design and deliver aspects of computer programming environments and instructional materials is discussed.

  1. Mechanism of Perceptual Attention

    National Research Council Canada - National Science Library

    Lu, Zhong-Lin

    2000-01-01

    .... Attention may affect the perceived clarity of visual displays and improve performance. In this project, a powerful external noise method was developed to identify and characterize the effect of attention on perceptual performance in visual tasks...

  2. Mechanisms of Perceptual Attention

    National Research Council Canada - National Science Library

    Dosher, Barbara

    2000-01-01

    .... Attention may affect the perceived clarity of visual displays and improve performance. In this project, a powerful external noise method was developed to identify and characterize the effect of attention on perceptual performance in visual tasks...

  3. Multimedia instructions and cognitive load theory: effects of modality and cueing.

    Science.gov (United States)

    Tabbers, Huib K; Martens, Rob L; van Merriënboer, Jeroen J G

    2004-03-01

    Recent research on the influence of presentation format on the effectiveness of multimedia instructions has yielded some interesting results. According to cognitive load theory (Sweller, Van Merriënboer, & Paas, 1998) and Mayer's theory of multimedia learning (Mayer, 2001), replacing visual text with spoken text (the modality effect) and adding visual cues relating elements of a picture to the text (the cueing effect) both increase the effectiveness of multimedia instructions in terms of better learning results or less mental effort spent. The aim of this study was to test the generalisability of the modality and cueing effect in a classroom setting. The participants were 111 second-year students from the Department of Education at the University of Gent in Belgium (age between 19 and 25 years). The participants studied a web-based multimedia lesson on instructional design for about one hour. Afterwards they completed a retention and a transfer test. During both the instruction and the tests, self-report measures of mental effort were administered. Adding visual cues to the pictures resulted in higher retention scores, while replacing visual text with spoken text resulted in lower retention and transfer scores. Only a weak cueing effect and even a reverse modality effect have been found, indicating that both effects do not easily generalise to non-laboratory settings. A possible explanation for the reversed modality effect is that the multimedia instructions in this study were learner-paced, as opposed to the system-paced instructions used in earlier research.

  4. Psychophysical indices of perceptual functioning in dyslexia: A psychometric analysis

    OpenAIRE

    Heath, Steve M.; Bishop, Dorothy V. M.; Hogben, John H.; Roach, Neil W.

    2006-01-01

    An influential causal theory attributes dyslexia to visual and/or auditory perceptual deficits. This theory derives from group differences between individuals with dyslexia and controls on a range of psychophysical tasks, but there is substantial variation, both between individuals within a group and from task to task. We addressed two questions. First, do psychophysical measures have sufficient reliability to assess perceptual deficits in individuals? Second, do different psychophysical task...

  5. Perceptually-Inspired Computing

    Directory of Open Access Journals (Sweden)

    Ming Lin

    2015-08-01

    Full Text Available Human sensory systems allow individuals to see, hear, touch, and interact with the surrounding physical environment. Understanding human perception and its limit enables us to better exploit the psychophysics of human perceptual systems to design more efficient, adaptive algorithms and develop perceptually-inspired computational models. In this talk, I will survey some of recent efforts on perceptually-inspired computing with applications to crowd simulation and multimodal interaction. In particular, I will present data-driven personality modeling based on the results of user studies, example-guided physics-based sound synthesis using auditory perception, as well as perceptually-inspired simplification for multimodal interaction. These perceptually guided principles can be used to accelerating multi-modal interaction and visual computing, thereby creating more natural human-computer interaction and providing more immersive experiences. I will also present their use in interactive applications for entertainment, such as video games, computer animation, and shared social experience. I will conclude by discussing possible future research directions.

  6. Perceptual dimensions differentiate emotions.

    Science.gov (United States)

    Cavanaugh, Lisa A; MacInnis, Deborah J; Weiss, Allen M

    2015-08-26

    Individuals often describe objects in their world in terms of perceptual dimensions that span a variety of modalities; the visual (e.g., brightness: dark-bright), the auditory (e.g., loudness: quiet-loud), the gustatory (e.g., taste: sour-sweet), the tactile (e.g., hardness: soft vs. hard) and the kinaesthetic (e.g., speed: slow-fast). We ask whether individuals use perceptual dimensions to differentiate emotions from one another. Participants in two studies (one where respondents reported on abstract emotion concepts and a second where they reported on specific emotion episodes) rated the extent to which features anchoring 29 perceptual dimensions (e.g., temperature, texture and taste) are associated with 8 emotions (anger, fear, sadness, guilt, contentment, gratitude, pride and excitement). Results revealed that in both studies perceptual dimensions differentiate positive from negative emotions and high arousal from low arousal emotions. They also differentiate among emotions that are similar in arousal and valence (e.g., high arousal negative emotions such as anger and fear). Specific features that anchor particular perceptual dimensions (e.g., hot vs. cold) are also differentially associated with emotions.

  7. Cognitive Load Theory and the Acquisition of Complex Cognitive Skills in the Elderly: Towards an Integrative Framework.

    Science.gov (United States)

    Van Gerven, Pascal W. M.; Paas, Fred G. W. C.; Van Merrienboer, Jeroen J. G.; Schmidt, Henk G.

    2000-01-01

    Cognitive load (CL) theory suggests minimizing extraneous CL and maximizing germane CL in order not to overload working memory. Instructional design for older adults should therefore include goal-free problems, worked examples, and different modalities and avoid splitting attention and including redundant information. (SK)

  8. Features of Representations in General Chemistry Textbooks: A Peek through the Lens of the Cognitive Load Theory

    Science.gov (United States)

    Nyachwaya, James M.; Gillaspie, Merry

    2016-01-01

    The goals of this study were (1) determine the prevalence of various features of representations in five general chemistry textbooks used in the United States, and (2) use cognitive load theory to draw implications of the various features of analyzed representations. We adapted the Graphical Analysis Protocol (GAP) (Slough et al., 2010) to look at…

  9. Aerodynamic loads calculation and analysis for large scale wind turbine based on combining BEM modified theory with dynamic stall model

    Energy Technology Data Exchange (ETDEWEB)

    Dai, J.C. [College of Mechanical and Electrical Engineering, Central South University, Changsha (China); School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Hu, Y.P.; Liu, D.S. [School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Long, X. [Hara XEMC Windpower Co., Ltd., Xiangtan (China)

    2011-03-15

    The aerodynamic loads for MW scale horizontal-axis wind turbines are calculated and analyzed in the established coordinate systems which are used to describe the wind turbine. In this paper, the blade element momentum (BEM) theory is employed and some corrections, such as Prandtl and Buhl models, are carried out. Based on the B-L semi-empirical dynamic stall (DS) model, a new modified DS model for NACA63-4xx airfoil is adopted. Then, by combing BEM modified theory with DS model, a set of calculation method of aerodynamic loads for large scale wind turbines is proposed, in which some influence factors such as wind shear, tower, tower and blade vibration are considered. The research results show that the presented dynamic stall model is good enough for engineering purpose; the aerodynamic loads are influenced by many factors such as tower shadow, wind shear, dynamic stall, tower and blade vibration, etc, with different degree; the single blade endures periodical changing loads but the variations of the rotor shaft power caused by the total aerodynamic torque in edgewise direction are very small. The presented study approach of aerodynamic loads calculation and analysis is of the university, and helpful for thorough research of loads reduction on large scale wind turbines. (author)

  10. Applying cognitive load theory to the redesign of a conventional database systems course

    Science.gov (United States)

    Mason, Raina; Seton, Carolyn; Cooper, Graham

    2016-01-01

    Cognitive load theory (CLT) was used to redesign a Database Systems course for Information Technology students. The redesign was intended to address poor student performance and low satisfaction, and to provide a more relevant foundation in database design and use for subsequent studies and industry. The original course followed the conventional structure for a database course, covering database design first, then database development. Analysis showed the conventional course content was appropriate but the instructional materials used were too complex, especially for novice students. The redesign of instructional materials applied CLT to remove split attention and redundancy effects, to provide suitable worked examples and sub-goals, and included an extensive re-sequencing of content. The approach was primarily directed towards mid- to lower performing students and results showed a significant improvement for this cohort with the exam failure rate reducing by 34% after the redesign on identical final exams. Student satisfaction also increased and feedback from subsequent study was very positive. The application of CLT to the design of instructional materials is discussed for delivery of technical courses.

  11. Cognitive Load Theory: An Empirical Study of Anxiety and Task Performance in Language Learning

    Science.gov (United States)

    Chen, I-Jung; Chang, Chi-Cheng

    2009-01-01

    Introduction: This study explores the relationship among three variables--cognitive load, foreign language anxiety, and task performance. Cognitive load refers to the load imposed on working memory while performing a particular task. The authors hypothesized that anxiety consumes the resources of working memory, leaving less capacity for cognitive…

  12. The effect of implementing cognitive load theory-based design principles in virtual reality simulation training of surgical skills: a randomized controlled trial

    DEFF Research Database (Denmark)

    Andersen, Steven Arild Wuyts; Mikkelsen, Peter Trier; Konge, Lars

    2016-01-01

    Cognitive overload can inhibit learning, and cognitive load theory-based instructional design principles can be used to optimize learning situations. This study aims to investigate the effect of implementing cognitive load theory-based design principles in virtual reality simulation training...

  13. Auditory working memory load impairs visual ventral stream processing: toward a unified model of attentional load.

    Science.gov (United States)

    Klemen, Jane; Büchel, Christian; Bühler, Mira; Menz, Mareike M; Rose, Michael

    2010-03-01

    Attentional interference between tasks performed in parallel is known to have strong and often undesired effects. As yet, however, the mechanisms by which interference operates remain elusive. A better knowledge of these processes may facilitate our understanding of the effects of attention on human performance and the debilitating consequences that disruptions to attention can have. According to the load theory of cognitive control, processing of task-irrelevant stimuli is increased by attending in parallel to a relevant task with high cognitive demands. This is due to the relevant task engaging cognitive control resources that are, hence, unavailable to inhibit the processing of task-irrelevant stimuli. However, it has also been demonstrated that a variety of types of load (perceptual and emotional) can result in a reduction of the processing of task-irrelevant stimuli, suggesting a uniform effect of increased load irrespective of the type of load. In the present study, we concurrently presented a relevant auditory matching task [n-back working memory (WM)] of low or high cognitive load (1-back or 2-back WM) and task-irrelevant images at one of three object visibility levels (0%, 50%, or 100%). fMRI activation during the processing of the task-irrelevant visual stimuli was measured in the lateral occipital cortex and found to be reduced under high, compared to low, WM load. In combination with previous findings, this result is suggestive of a more generalized load theory, whereby cognitive load, as well as other types of load (e.g., perceptual), can result in a reduction of the processing of task-irrelevant stimuli, in line with a uniform effect of increased load irrespective of the type of load.

  14. Adaptation and perceptual norms

    Science.gov (United States)

    Webster, Michael A.; Yasuda, Maiko; Haber, Sara; Leonard, Deanne; Ballardini, Nicole

    2007-02-01

    We used adaptation to examine the relationship between perceptual norms--the stimuli observers describe as psychologically neutral, and response norms--the stimulus levels that leave visual sensitivity in a neutral or balanced state. Adapting to stimuli on opposite sides of a neutral point (e.g. redder or greener than white) biases appearance in opposite ways. Thus the adapting stimulus can be titrated to find the unique adapting level that does not bias appearance. We compared these response norms to subjectively defined neutral points both within the same observer (at different retinal eccentricities) and between observers. These comparisons were made for visual judgments of color, image focus, and human faces, stimuli that are very different and may depend on very different levels of processing, yet which share the property that for each there is a well defined and perceptually salient norm. In each case the adaptation aftereffects were consistent with an underlying sensitivity basis for the perceptual norm. Specifically, response norms were similar to and thus covaried with the perceptual norm, and under common adaptation differences between subjectively defined norms were reduced. These results are consistent with models of norm-based codes and suggest that these codes underlie an important link between visual coding and visual experience.

  15. Acetylcholine and Olfactory Perceptual Learning

    Science.gov (United States)

    Wilson, Donald A.; Fletcher, Max L.; Sullivan, Regina M.

    2004-01-01

    Olfactory perceptual learning is a relatively long-term, learned increase in perceptual acuity, and has been described in both humans and animals. Data from recent electrophysiological studies have indicated that olfactory perceptual learning may be correlated with changes in odorant receptive fields of neurons in the olfactory bulb and piriform…

  16. Patterns of interactions at grade 5 classroom in learning the topic of statistics viewed from cognitive load theory

    Science.gov (United States)

    Setianingsih, R.

    2018-01-01

    The nature of interactions that occurs among teacher, students, learning sources, and learning environment creates different settings to enhance learning. Any setting created by a teacher is affected by 3 (three) types of cognitive load: intrinsic cognitive load, extraneous cognitive load, and germane cognitive load. This study is qualitative in nature, aims to analyse the patterns of interaction that are constituted in mathematics instructions by taking into account the cognitive load theory. The subjects of this study are 21 fifth-grade students who learn mathematics in small groups and whole-class interactive lessons. The data were collected through classroom observations which were videotaped, while field notes were also taken. The data analysis revealed that students engaged in productive interaction and inquiry while they were learning mathematics in small groups or in whole class setting, in which there was a different type of cognitive load that dominantly affecting the learning processes at each setting. During learning mathematics in whole class setting, the most frequently found interaction patterns were to discuss and compare solution based on self-developed models, followed by expressing opinions. This is consistent with the principles of mathematics learning, which gives students wide opportunities to construct mathematical knowledge through individual learning, learning in small groups as well as learning in whole class settings. It means that by participating in interactive learning, the students are habitually engaged in productive interactions and high level of mathematical thinking.

  17. Distracted and confused?: selective attention under load.

    Science.gov (United States)

    Lavie, Nilli

    2005-02-01

    The ability to remain focused on goal-relevant stimuli in the presence of potentially interfering distractors is crucial for any coherent cognitive function. However, simply instructing people to ignore goal-irrelevant stimuli is not sufficient for preventing their processing. Recent research reveals that distractor processing depends critically on the level and type of load involved in the processing of goal-relevant information. Whereas high perceptual load can eliminate distractor processing, high load on "frontal" cognitive control processes increases distractor processing. These findings provide a resolution to the long-standing early and late selection debate within a load theory of attention that accommodates behavioural and neuroimaging data within a framework that integrates attention research with executive function.

  18. Perceptual learning and human expertise.

    Science.gov (United States)

    Kellman, Philip J; Garrigan, Patrick

    2009-06-01

    We consider perceptual learning: experience-induced changes in the way perceivers extract information. Often neglected in scientific accounts of learning and in instruction, perceptual learning is a fundamental contributor to human expertise and is crucial in domains where humans show remarkable levels of attainment, such as language, chess, music, and mathematics. In Section 2, we give a brief history and discuss the relation of perceptual learning to other forms of learning. We consider in Section 3 several specific phenomena, illustrating the scope and characteristics of perceptual learning, including both discovery and fluency effects. We describe abstract perceptual learning, in which structural relationships are discovered and recognized in novel instances that do not share constituent elements or basic features. In Section 4, we consider primary concepts that have been used to explain and model perceptual learning, including receptive field change, selection, and relational recoding. In Section 5, we consider the scope of perceptual learning, contrasting recent research, focused on simple sensory discriminations, with earlier work that emphasized extraction of invariance from varied instances in more complex tasks. Contrary to some recent views, we argue that perceptual learning should not be confined to changes in early sensory analyzers. Phenomena at various levels, we suggest, can be unified by models that emphasize discovery and selection of relevant information. In a final section, we consider the potential role of perceptual learning in educational settings. Most instruction emphasizes facts and procedures that can be verbalized, whereas expertise depends heavily on implicit pattern recognition and selective extraction skills acquired through perceptual learning. We consider reasons why perceptual learning has not been systematically addressed in traditional instruction, and we describe recent successful efforts to create a technology of perceptual

  19. Perceptual learning and human expertise

    Science.gov (United States)

    Kellman, Philip J.; Garrigan, Patrick

    2009-06-01

    We consider perceptual learning: experience-induced changes in the way perceivers extract information. Often neglected in scientific accounts of learning and in instruction, perceptual learning is a fundamental contributor to human expertise and is crucial in domains where humans show remarkable levels of attainment, such as language, chess, music, and mathematics. In Section 2, we give a brief history and discuss the relation of perceptual learning to other forms of learning. We consider in Section 3 several specific phenomena, illustrating the scope and characteristics of perceptual learning, including both discovery and fluency effects. We describe abstract perceptual learning, in which structural relationships are discovered and recognized in novel instances that do not share constituent elements or basic features. In Section 4, we consider primary concepts that have been used to explain and model perceptual learning, including receptive field change, selection, and relational recoding. In Section 5, we consider the scope of perceptual learning, contrasting recent research, focused on simple sensory discriminations, with earlier work that emphasized extraction of invariance from varied instances in more complex tasks. Contrary to some recent views, we argue that perceptual learning should not be confined to changes in early sensory analyzers. Phenomena at various levels, we suggest, can be unified by models that emphasize discovery and selection of relevant information. In a final section, we consider the potential role of perceptual learning in educational settings. Most instruction emphasizes facts and procedures that can be verbalized, whereas expertise depends heavily on implicit pattern recognition and selective extraction skills acquired through perceptual learning. We consider reasons why perceptual learning has not been systematically addressed in traditional instruction, and we describe recent successful efforts to create a technology of perceptual

  20. Cognitive Load and Self-Determination Theories Applied to E-Learning: Impact on Students' Participation and Academic Performance.

    Science.gov (United States)

    de Araujo Guerra Grangeia, Tiago; de Jorge, Bruno; Franci, Daniel; Martins Santos, Thiago; Vellutini Setubal, Maria Silvia; Schweller, Marcelo; de Carvalho-Filho, Marco Antonio

    2016-01-01

    Emergency clerkships expose students to a stressful environment that require multiple tasks, which may have a direct impact on cognitive load and motivation for learning. To address this challenge, Cognitive Load Theory and Self Determination Theory provided the conceptual frameworks to the development of a Moodle-based online Emergency Medicine course, inspired by real clinical cases. Three consecutive classes (2013-2015) of sixth-year medical students (n = 304) participated in the course, during a curricular and essentially practical emergency rotation. "Virtual Rounds" provided weekly virtual patients in narrative format and meaningful schemata to chief complaints, in order to simulate real rounds at Emergency Unit. Additional activities such as Extreme Decisions, Emergency Quiz and Electrocardiographic challenge offered different views of emergency care. Authors assessed student´s participation and its correlation with their academic performance. A survey evaluated students´ opinions. Students graduating in 2015 answered an online questionnaire to investigate cognitive load and motivation. Each student produced 1965 pageviews and spent 72 hours logged on. Although Clinical Emergency rotation has two months long, students accessed the online course during an average of 5.3 months. Virtual Rounds was the most accessed activity, and there was positive correlations between the number of hours logged on the platform and final grades on Emergency Medicine. Over 90% of students felt an improvement in their clinical reasoning and considered themselves better prepared for rendering Emergency care. Considering a Likert scale from 1 (minimum load) to 7 (maximum load), the scores for total cognitive load were 4.79±2.2 for Virtual Rounds and 5.56±1.96 for real medical rounds(pcognitive and motivational conceptual frameworks, seems to be a strong tool to engage students in learning. It may support them to manage the cognitive challenges involved in clinical care and

  1. Cognitive Load and Self-Determination Theories Applied to E-Learning: Impact on Students' Participation and Academic Performance.

    Directory of Open Access Journals (Sweden)

    Tiago de Araujo Guerra Grangeia

    Full Text Available Emergency clerkships expose students to a stressful environment that require multiple tasks, which may have a direct impact on cognitive load and motivation for learning. To address this challenge, Cognitive Load Theory and Self Determination Theory provided the conceptual frameworks to the development of a Moodle-based online Emergency Medicine course, inspired by real clinical cases.Three consecutive classes (2013-2015 of sixth-year medical students (n = 304 participated in the course, during a curricular and essentially practical emergency rotation. "Virtual Rounds" provided weekly virtual patients in narrative format and meaningful schemata to chief complaints, in order to simulate real rounds at Emergency Unit. Additional activities such as Extreme Decisions, Emergency Quiz and Electrocardiographic challenge offered different views of emergency care. Authors assessed student´s participation and its correlation with their academic performance. A survey evaluated students´ opinions. Students graduating in 2015 answered an online questionnaire to investigate cognitive load and motivation.Each student produced 1965 pageviews and spent 72 hours logged on. Although Clinical Emergency rotation has two months long, students accessed the online course during an average of 5.3 months. Virtual Rounds was the most accessed activity, and there was positive correlations between the number of hours logged on the platform and final grades on Emergency Medicine. Over 90% of students felt an improvement in their clinical reasoning and considered themselves better prepared for rendering Emergency care. Considering a Likert scale from 1 (minimum load to 7 (maximum load, the scores for total cognitive load were 4.79±2.2 for Virtual Rounds and 5.56±1.96 for real medical rounds(p<0,01.A real-world inspired online course, based on cognitive and motivational conceptual frameworks, seems to be a strong tool to engage students in learning. It may support them to

  2. Dynamic analysis of isotropic nanoplates subjected to moving load using state-space method based on nonlocal second order plate theory

    Energy Technology Data Exchange (ETDEWEB)

    Nami, Mohammad Rahim [Shiraz University, Shiraz, Iran (Iran, Islamic Republic of); Janghorban, Maziar [Islamic Azad University, Marvdash (Iran, Islamic Republic of)

    2015-06-15

    In this work, dynamic analysis of rectangular nanoplates subjected to moving load is presented. In order to derive the governing equations of motion, second order plate theory is used. To capture the small scale effects, the nonlocal elasticity theory is adopted. It is assumed that the nanoplate is subjected to a moving concentrated load with the constant velocity V in the x direction. To solve the governing equations, state-space method is used to find the deflections of rectangular nanoplate under moving load. The results obtained here reveal that the nonlocality has significant effect on the deflection of rectangular nanoplate subjected to moving load.

  3. Development of an aerodyanmic theory capable of predicting surface loads on slender wings with vortex flow

    Science.gov (United States)

    Gloss, B. B.; Johnson, F. T.

    1976-01-01

    The Boeing Commercial Airplane Company developed an inviscid three-dimensional lifting surface method that shows promise in being able to accurately predict loads, subsonic and supersonic, on wings with leading-edge separation and reattachment.

  4. Optimizing load transfer in multiwall nanotubes through interwall coupling: Theory and simulation

    International Nuclear Information System (INIS)

    Byrne, E.M.; Letertre, A.; McCarthy, M.A.; Curtin, W.A.; Xia, Z.

    2010-01-01

    An analytical model is developed to determine the length scales over which load is transferred from outer to inner walls of multiwall carbon nanotubes (MWCNTs) as a function of the amount of bonding between walls. The model predicts that the characteristic length for load transfer scales as l∼t√(E/μ-bar), where t is the CNT wall spacing, E is the effective wall Young's modulus, and μ-bar is the average interwall shear modulus due to interwall coupling. Molecular dynamics simulations for MWCNTs with up to six walls, and with interwall coupling achieved by interwall sp 3 bonding at various densities, provide data against which the model is tested. For interwall bonding having a uniform axial distribution, the analytic and simulation models agree well, showing that continuum mechanics concepts apply down to the atomic scale in this problem. The simulation models show, however, that load transfer is sensitive to natural statistical fluctuations in the spatial distribution of the interwall bonding between pairs of walls, and such fluctuations generally increase the net load transfer length needed to fully load an MWCNT. Optimal load transfer is achieved when bonding is uniformly distributed axially, and all interwall regions have the same shear stiffness, implying a linear decrease in the number of interwall bonds with distance from the outer wall. Optimal load transfer into an n-wall MWCNT is shown to occur over a length of ∼1.5nl. The model can be used to design MWCNTs for structural materials, and to interpret load transfer characteristics deduced from experiments on individual MWCNTs.

  5. Complete mechanical behavior analysis of FG Nano Beam under non-uniform loading using non-local theory

    Science.gov (United States)

    Ghaffari, I.; Parhizkar Yaghoobi, M.; Ghannad, M.

    2018-01-01

    The purpose of this study is to offer a complete solution to analyze the mechanical behavior (bending, buckling and vibration) of Nano-beam under non-uniform loading. Furthermore, the effects of size (nonlocal parameters), non-homogeneity constants, and different boundary conditions are investigated by using this method. The exact solution presented here reduces costs incurred by experiments. In this research, the displacement field obeys the kinematics of the Euler-Bernoulli beam theory and non-local elasticity theory has been used. The governing equations and general boundary conditions are derived for a beam by using energy method. The presented solution enables us to analyze any kind of loading profile and boundary conditions with no limitations. Furthermore, this solution, unlike previous studies, is not a series-solution; hence, there is no limitation prior to existing with the series-solution, nor does it need to check convergence. Based on the developed analytical solution, the influence of size, non-homogeneity and non-uniform loads on bending, buckling and vibration behaviors is discussed. Also, the obtained result is highly accurate and in good agreement with previous research. In theoretical method, the allowable range for non-local parameters can be determined so as to make a major contribution to the reduction of the cost of experiments determining the value of non-local parameters.

  6. Non-Linear Wave Loads and Ship responses by a time-domain Strip Theory

    DEFF Research Database (Denmark)

    Xia, Jinzhu; Wang, Zhaohui; Jensen, Jørgen Juncher

    1998-01-01

    . Based on this time-domain strip theory, an efficient non-linear hyroelastic method of wave- and slamming-induced vertical motions and structural responses of ships is developed, where the structure is represented by the Timoshenko beam theory. Numerical calculations are presented for the S175...

  7. Perceptual organization and visual attention.

    Science.gov (United States)

    Kimchi, Ruth

    2009-01-01

    Perceptual organization--the processes structuring visual information into coherent units--and visual attention--the processes by which some visual information in a scene is selected--are crucial for the perception of our visual environment and to visuomotor behavior. Recent research points to important relations between attentional and organizational processes. Several studies demonstrated that perceptual organization constrains attentional selectivity, and other studies suggest that attention can also constrain perceptual organization. In this chapter I focus on two aspects of the relationship between perceptual organization and attention. The first addresses the question of whether or not perceptual organization can take place without attention. I present findings demonstrating that some forms of grouping and figure-ground segmentation can occur without attention, whereas others require controlled attentional processing, depending on the processes involved and the conditions prevailing for each process. These findings challenge the traditional view, which assumes that perceptual organization is a unitary entity that operates preattentively. The second issue addresses the question of whether perceptual organization can affect the automatic deployment of attention. I present findings showing that the mere organization of some elements in the visual field by Gestalt factors into a coherent perceptual unit (an "object"), with no abrupt onset or any other unique transient, can capture attention automatically in a stimulus-driven manner. Taken together, the findings discussed in this chapter demonstrate the multifaceted, interactive relations between perceptual organization and visual attention.

  8. The effect of implementing cognitive load theory-based design principles in virtual reality simulation training of surgical skills: a randomized controlled trial

    DEFF Research Database (Denmark)

    Andersen, Steven Arild Wuyts; Mikkelsen, Peter Trier; Konge, Lars

    2016-01-01

    training of mastoidectomy. Methods Eighteen novice medical students received 1 h of self-directed virtual reality simulation training of the mastoidectomy procedure randomized for standard instructions (control) or cognitive load theory-based instructions with a worked example followed by a problem......Background Cognitive overload can inhibit learning, and cognitive load theory-based instructional design principles can be used to optimize learning situations. This study aims to investigate the effect of implementing cognitive load theory-based design principles in virtual reality simulation....... Increased cognitive load when part tasks needed to be integrated in the post-training procedures could be a possible explanation for this. Other instructional designs and methods are needed to lower the cognitive load and improve the performance in virtual reality surgical simulation training of novices....

  9. Load Frequency Control in Isolated Micro-Grids with Electrical Vehicles Based on Multivariable Generalized Predictive Theory

    Directory of Open Access Journals (Sweden)

    Jun Yang

    2015-03-01

    Full Text Available In power systems, although the inertia energy in power sources can partly cover power unbalances caused by load disturbance or renewable energy fluctuation, it is still hard to maintain the frequency deviation within acceptable ranges. However, with the vehicle-to-grid (V2G technique, electric vehicles (EVs can act as mobile energy storage units, which could be a solution for load frequency control (LFC in an isolated grid. In this paper, a LFC model of an isolated micro-grid with EVs, distributed generations and their constraints is developed. In addition, a controller based on multivariable generalized predictive control (MGPC theory is proposed for LFC in the isolated micro-grid, where EVs and diesel generator (DG are coordinated to achieve a satisfied performance on load frequency. A benchmark isolated micro-grid with EVs, DG, and wind farm is modeled in the Matlab/Simulink environment to demonstrate the effectiveness of the proposed method. Simulation results demonstrate that with MGPC, the energy stored in EVs can be managed intelligently according to LFC requirement. This improves the system frequency stability with complex operation situations including the random renewable energy resource and the continuous load disturbances.

  10. The Role of Language Glossing in a Rooted Theory: The Involvement Load Hypothesis

    Directory of Open Access Journals (Sweden)

    Hassan Soleimani

    2014-07-01

    Full Text Available This study builds on the innovative construct of task-induced involvement. It investigates different first and second language glossing in “involvement load hypothesis”. In order to do our study, 66 learners from two different English institutes were classified into two major high and low proficient groups based on Nelson Proficiency Test. Among them 22 low proficient students were randomly assigned to two different subgroups in order to complete two different types of tasks with different language glossing. The behaviors of the two groups in the immediate and delayed posttests did not confirm the predictions of involvement load hypothesis. Although the second task had a higher involvement index, no sign of superiority was observed in its performance. The study suggests that the predictions of involvement load hypothesis need to be more finely grained especially when the tasks have different language glossing.

  11. From Perceptual Categories to Concepts: What Develops?

    Science.gov (United States)

    Sloutsky, Vladimir M.

    2010-01-01

    People are remarkably smart: they use language, possess complex motor skills, make non-trivial inferences, develop and use scientific theories, make laws, and adapt to complex dynamic environments. Much of this knowledge requires concepts and this paper focuses on how people acquire concepts. It is argued that conceptual development progresses from simple perceptual grouping to highly abstract scientific concepts. This proposal of conceptual development has four parts. First, it is argued that categories in the world have different structure. Second, there might be different learning systems (sub-served by different brain mechanisms) that evolved to learn categories of differing structures. Third, these systems exhibit differential maturational course, which affects how categories of different structures are learned in the course of development. And finally, an interaction of these components may result in the developmental transition from perceptual groupings to more abstract concepts. This paper reviews a large body of empirical evidence supporting this proposal. PMID:21116483

  12. Perceptual Audio Hashing Functions

    Directory of Open Access Journals (Sweden)

    Emin Anarım

    2005-07-01

    Full Text Available Perceptual hash functions provide a tool for fast and reliable identification of content. We present new audio hash functions based on summarization of the time-frequency spectral characteristics of an audio document. The proposed hash functions are based on the periodicity series of the fundamental frequency and on singular-value description of the cepstral frequencies. They are found, on one hand, to perform very satisfactorily in identification and verification tests, and on the other hand, to be very resilient to a large variety of attacks. Moreover, we address the issue of security of hashes and propose a keying technique, and thereby a key-dependent hash function.

  13. A Knowledge Conversion Model Based on the Cognitive Load Theory for Architectural Design Education

    Science.gov (United States)

    Wu, Yun-Wu; Liao, Shin; Wen, Ming-Hui; Weng, Kuo-Hua

    2017-01-01

    The education of architectural design requires balanced curricular arrangements of respectively theoretical knowledge and practical skills to really help students build their knowledge structures, particularly helping them in solving the problems of cognitive load. The purpose of this study is to establish an architectural design knowledge…

  14. Application of Hierarchy Theory to Cross-Scale Hydrologic Modeling of Nutrient Loads

    Science.gov (United States)

    We describe a model called Regional Hydrologic Modeling for Environmental Evaluation 16 (RHyME2) for quantifying annual nutrient loads in stream networks and watersheds. RHyME2 is 17 a cross-scale statistical and process-based water-quality model. The model ...

  15. An Examination of Game-Based Learning from Theories of Flow Experience and Cognitive Load

    Science.gov (United States)

    Lai, Chih-Hung; Chu, Chih-Ming; Liu, Hsiang-Hsuan; Yang, Shun-Bo; Chen, Wei-Hsuan

    2013-01-01

    This study aims to discuss whether game-based learning with the integration of games and digital learning could enhance not only the flow experience in learning but achieve the same flow experience in pure games. In addition, the authors discovered that whether the game-based learning could make learners to reveal higher cognitive load. The…

  16. Using Cognitive Load Theory to Tailor Instruction to Levels of Accounting Students' Expertise

    Science.gov (United States)

    Blayney, Paul; Kalyuga, Slava; Sweller, John

    2015-01-01

    Tailoring of instructional methods to learner levels of expertise may reduce extraneous cognitive load and improve learning. Contemporary technology-based learning environments have the potential to substantially enable learner-adapted instruction. This paper investigates the effects of adaptive instruction based on using the isolated-interactive…

  17. An Evolutionary Upgrade of Cognitive Load Theory: Using the Human Motor System and Collaboration to Support the Learning of Complex Cognitive Tasks

    NARCIS (Netherlands)

    G.W.C. Paas (Fred); J. Sweller (John)

    2012-01-01

    textabstractCognitive load theory is intended to provide instructional strategies derived from experimental, cognitive load effects. Each effect is based on our knowledge of human cognitive architecture, primarily the limited capacity and duration of a human working memory. These limitations are

  18. An Evolutionary Upgrade of Cognitive Load Theory: Using the Human Motor System and Collaboration to Support the Learning of Complex Cognitive Tasks

    Science.gov (United States)

    Paas, Fred; Sweller, John

    2012-01-01

    Cognitive load theory is intended to provide instructional strategies derived from experimental, cognitive load effects. Each effect is based on our knowledge of human cognitive architecture, primarily the limited capacity and duration of a human working memory. These limitations are ameliorated by changes in long-term memory associated with…

  19. Performances of synchrotron X-ray monochromators under heat load. Part 2. Application of the Takagi-Taupin diffraction theory

    CERN Document Server

    Mocella, V; Freund, A K; Hoszowska, J; Zhang, L; Epelboin, Y

    2001-01-01

    The aim of this work is to generate the rocking curves of monochromators exposed to heat load in synchrotron radiation beams with a computer code performing diffraction calculations based on the theory of Takagi and Taupin. The model study starts with the calculation of deformation by finite element analysis and from an accurate characterization of the incident wave and includes the simulation of the wavefront propagation between the first and the second crystal (analyzer) of a double crystal monochromator. A monochromatic plane wave as well as a polychromatic spherical wave approach is described. The theoretical predictions of both methods are compared with experimental data measured in Bragg geometry and critically discussed.

  20. Performances of synchrotron X-ray monochromators under heat load. Part 2. Application of the Takagi-Taupin diffraction theory

    International Nuclear Information System (INIS)

    Mocella, V.; Ferrero, C.; Freund, A.K.; Hoszowska, J.; Zhang, L.; Epelboin, Y.

    2001-01-01

    The aim of this work is to generate the rocking curves of monochromators exposed to heat load in synchrotron radiation beams with a computer code performing diffraction calculations based on the theory of Takagi and Taupin. The model study starts with the calculation of deformation by finite element analysis and from an accurate characterization of the incident wave and includes the simulation of the wavefront propagation between the first and the second crystal (analyzer) of a double crystal monochromator. A monochromatic plane wave as well as a polychromatic spherical wave approach is described. The theoretical predictions of both methods are compared with experimental data measured in Bragg geometry and critically discussed

  1. Effect of thermal loading due to laser pulse on thermoelastic porous medium under G-N theory

    Directory of Open Access Journals (Sweden)

    Mohamed I.A. Othman

    Full Text Available The aim of this paper is to study the wave propagation of generalized thermoelastic medium with voids under the effect of thermal loading due to laser pulse with energy dissipation. The material is a homogeneous isotropic elastic half-space and heated by a non-Gaussian laser beam with the pulse duration of 0.2 ps. A normal mode method is proposed to analyse the problem and obtain numerical solutions for the displacement components, stresses, temperature distribution and the change in the volume fraction field. The results of the physical quantities have been illustrated graphically by comparison between both types II and III of Green-Naghdi theory for two values of time, as well as with and without void parameters. Keywords: Laser pulse, Voids, Energy dissipation, Green-Naghdi theory, Wave propagation, Thermoelasticity

  2. Visual short-term memory load reduces retinotopic cortex response to contrast.

    Science.gov (United States)

    Konstantinou, Nikos; Bahrami, Bahador; Rees, Geraint; Lavie, Nilli

    2012-11-01

    Load Theory of attention suggests that high perceptual load in a task leads to reduced sensory visual cortex response to task-unrelated stimuli resulting in "load-induced blindness" [e.g., Lavie, N. Attention, distraction and cognitive control under load. Current Directions in Psychological Science, 19, 143-148, 2010; Lavie, N. Distracted and confused?: Selective attention under load. Trends in Cognitive Sciences, 9, 75-82, 2005]. Consideration of the findings that visual STM (VSTM) involves sensory recruitment [e.g., Pasternak, T., & Greenlee, M. Working memory in primate sensory systems. Nature Reviews Neuroscience, 6, 97-107, 2005] within Load Theory led us to a new hypothesis regarding the effects of VSTM load on visual processing. If VSTM load draws on sensory visual capacity, then similar to perceptual load, high VSTM load should also reduce visual cortex response to incoming stimuli leading to a failure to detect them. We tested this hypothesis with fMRI and behavioral measures of visual detection sensitivity. Participants detected the presence of a contrast increment during the maintenance delay in a VSTM task requiring maintenance of color and position. Increased VSTM load (manipulated by increased set size) led to reduced retinotopic visual cortex (V1-V3) responses to contrast as well as reduced detection sensitivity, as we predicted. Additional visual detection experiments established a clear tradeoff between the amount of information maintained in VSTM and detection sensitivity, while ruling out alternative accounts for the effects of VSTM load in terms of differential spatial allocation strategies or task difficulty. These findings extend Load Theory to demonstrate a new form of competitive interactions between early visual cortex processing and visual representations held in memory under load and provide a novel line of support for the sensory recruitment hypothesis of VSTM.

  3. Perceptual integration without conscious access

    NARCIS (Netherlands)

    Fahrenfort, Johannes J.; Van Leeuwen, Jonathan; Olivers, Christian N.L.; Hogendoorn, Hinze

    2017-01-01

    The visual system has the remarkable ability to integrate fragmentary visual input into a perceptually organized collection of surfaces and objects, a process we refer to as perceptual integration. Despite a long tradition of perception research, it is not known whether access to consciousness is

  4. Reactive agents and perceptual ambiguity

    NARCIS (Netherlands)

    Dartel, M. van; Sprinkhuizen-Kuyper, I.G.; Postma, E.O.; Herik, H.J. van den

    2005-01-01

    Reactive agents are generally believed to be incapable of coping with perceptual ambiguity (i.e., identical sensory states that require different responses). However, a recent finding suggests that reactive agents can cope with perceptual ambiguity in a simple model (Nolfi, 2002). This paper

  5. Integrated approaches to perceptual learning.

    Science.gov (United States)

    Jacobs, Robert A

    2010-04-01

    New technologies and new ways of thinking have recently led to rapid expansions in the study of perceptual learning. We describe three themes shared by many of the nine articles included in this topic on Integrated Approaches to Perceptual Learning. First, perceptual learning cannot be studied on its own because it is closely linked to other aspects of cognition, such as attention, working memory, decision making, and conceptual knowledge. Second, perceptual learning is sensitive to both the stimulus properties of the environment in which an observer exists and to the properties of the tasks that the observer needs to perform. Moreover, the environmental and task properties can be characterized through their statistical regularities. Finally, the study of perceptual learning has important implications for society, including implications for science education and medical rehabilitation. Contributed articles relevant to each theme are summarized. Copyright © 2010 Cognitive Science Society, Inc.

  6. Tire-rim interface pressure of a commercial vehicle wheel under radial loads: theory and experiment

    Science.gov (United States)

    Wan, Xiaofei; Shan, Yingchun; Liu, Xiandong; He, Tian; Wang, Jiegong

    2017-11-01

    The simulation of the radial fatigue test of a wheel has been a necessary tool to improve the design of the wheel and calculate its fatigue life. The simulation model, including the strong nonlinearity of the tire structure and material, may produce accurate results, but often leads to a divergence in calculation. Thus, a simplified simulation model in which the complicated tire model is replaced with a tire-wheel contact pressure model is used extensively in the industry. In this paper, a simplified tire-rim interface pressure model of a wheel under a radial load is established, and the pressure of the wheel under different radial loads is tested. The tire-rim contact behavior affected by the radial load is studied and analyzed according to the test result, and the tire-rim interface pressure extracted from the test result is used to evaluate the simplified pressure model and the traditional cosine function model. The results show that the proposed model may provide a more accurate prediction of the wheel radial fatigue life than the traditional cosine function model.

  7. A Similitude Theory for Bucket Foundations Under Monotonic Horizontal Load in Dense Sand

    DEFF Research Database (Denmark)

    Foglia, Aligi; Ibsen, Lars Bo

    2013-01-01

    This paper aims at finding force-displacement relationships to be employed in the design of bucket foundations for offshore wind turbine. This is accomplished by combining small-scale tests and element tests within a theoretical framework. A similitude theory, regarding the lateral displacement o...

  8. Non-linear wave loads and ship responses by a time-domain strip theory

    DEFF Research Database (Denmark)

    Xia, Jinzhu; Wang, Zhaohui; Jensen, Jørgen Juncher

    1998-01-01

    . Based on this time-domain strip theory, an efficient non-linear hydroelastic method of wave- and slamming-induced vertical motions and structural responses of ships is developed, where the structure is represented as a Timoshenko beam. Numerical calculations are presented for the S175 Containership...

  9. Linear theory of a dielectric-loaded rectangular Cerenkov maser with a sheet electron beam

    International Nuclear Information System (INIS)

    Chen Ye; Wan Xiao-Sheng; Zhao Ding; Liu Wen-Xin; Wang Yong

    2012-01-01

    A three-dimensional model of a dielectric-loaded rectangular Cerenkov maser with a sheet electron beam for the beam-wave interaction is proposed. Based on this model, the hybrid-mode dispersion equation is derived with the Borgnis potential function by using the field-matching method. Its approximate solution is obtained under the assumption of a dilute electron beam. By using the Ansoft high frequency structural simulator (HFSS) code, the electromagnetic field distribution in the interaction structure is given. Through numerical calculations, the effects of beam thickness, beam and dielectric-layer gap distance, beam voltage, and current density on the resonant growth rate are analysed in detail

  10. Perceptual learning as improved probabilistic inference in early sensory areas.

    Science.gov (United States)

    Bejjanki, Vikranth R; Beck, Jeffrey M; Lu, Zhong-Lin; Pouget, Alexandre

    2011-05-01

    Extensive training on simple tasks such as fine orientation discrimination results in large improvements in performance, a form of learning known as perceptual learning. Previous models have argued that perceptual learning is due to either sharpening and amplification of tuning curves in early visual areas or to improved probabilistic inference in later visual areas (at the decision stage). However, early theories are inconsistent with the conclusions of psychophysical experiments manipulating external noise, whereas late theories cannot explain the changes in neural responses that have been reported in cortical areas V1 and V4. Here we show that we can capture both the neurophysiological and behavioral aspects of perceptual learning by altering only the feedforward connectivity in a recurrent network of spiking neurons so as to improve probabilistic inference in early visual areas. The resulting network shows modest changes in tuning curves, in line with neurophysiological reports, along with a marked reduction in the amplitude of pairwise noise correlations.

  11. Cognitive structure of occupational risks represented by a perceptual map.

    Science.gov (United States)

    Cardoso-Junior, M M; Scarpel, R A

    2012-01-01

    The main focus of risk management is technical and rational analysis about the operational risks and by those imposed by the occupational environment. In this work one seeks to contribute to the risk perception study and to better comprehend how a group of occupational safety students assesses a set of activities and environmental agents. In this way it was used theory sustained by psychometric paradigm and multivariate analysis tools, mainly multidimensional scaling, generalized Procrustes analysis and facets theory, in order to construct the perceptual map of occupational risks. The results obtained showed that the essential characteristics of risks, which were initially splited in 4 facets were detected and maintained in the perceptual map. It was not possible to reveal the cognitive structure of the group, because the variability of the students was too high. Differences among the risks analyzed could not be detected as well in the perceptual map of the group.

  12. Nonlinear adaptive robust back stepping force control of hydraulic load simulator: Theory and experiments

    International Nuclear Information System (INIS)

    Yao, Jianyong; Jiao, Zongxia; Yao, Bin

    2014-01-01

    High performance robust force control of hydraulic load simulator with constant but unknown hydraulic parameters is considered. In contrast to the linear control based on hydraulic linearization equations, hydraulic inherent nonlinear properties and uncertainties make the conventional feedback proportional-integral-derivative (PID) control not yield to high performance requirements. Furthermore, the hydraulic system may be subjected to non-smooth and discontinuous nonlinearities due to the directional change of valve opening. In this paper, based on a nonlinear system model of hydraulic load simulator, a discontinuous projection-based nonlinear adaptive robust back stepping controller is developed with servo valve dynamics. The proposed controller constructs a novel stable adaptive controller and adaptation laws with additional pressure dynamic related unknown parameters, which can compensate for the system nonlinearities and uncertain parameters, meanwhile a well-designed robust controller is also synthesized to dominate the model uncertainties coming from both parametric uncertainties and uncertain nonlinearities including unmodeled and ignored system dynamics. The controller theoretically guarantee a prescribed transient performance and final tracking accuracy in presence of both parametric uncertainties and uncertain nonlinearities; while achieving asymptotic output tracking in the absence of unstructured uncertainties. The implementation issues are also discussed for controller simplification. Some comparative results are obtained to verify the high-performance nature of the proposed controller.

  13. Nonlinear adaptive robust back stepping force control of hydraulic load simulator: Theory and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Jianyong [Nanjing University of Science and Technology, Nanjing (China); Jiao, Zongxia [Beihang University, Beijing (China); Yao, Bin [Purdue University, West Lafayette (United States)

    2014-04-15

    High performance robust force control of hydraulic load simulator with constant but unknown hydraulic parameters is considered. In contrast to the linear control based on hydraulic linearization equations, hydraulic inherent nonlinear properties and uncertainties make the conventional feedback proportional-integral-derivative (PID) control not yield to high performance requirements. Furthermore, the hydraulic system may be subjected to non-smooth and discontinuous nonlinearities due to the directional change of valve opening. In this paper, based on a nonlinear system model of hydraulic load simulator, a discontinuous projection-based nonlinear adaptive robust back stepping controller is developed with servo valve dynamics. The proposed controller constructs a novel stable adaptive controller and adaptation laws with additional pressure dynamic related unknown parameters, which can compensate for the system nonlinearities and uncertain parameters, meanwhile a well-designed robust controller is also synthesized to dominate the model uncertainties coming from both parametric uncertainties and uncertain nonlinearities including unmodeled and ignored system dynamics. The controller theoretically guarantee a prescribed transient performance and final tracking accuracy in presence of both parametric uncertainties and uncertain nonlinearities; while achieving asymptotic output tracking in the absence of unstructured uncertainties. The implementation issues are also discussed for controller simplification. Some comparative results are obtained to verify the high-performance nature of the proposed controller.

  14. Top-down (Prior Knowledge) and Bottom-up (Perceptual Modality) Influences on Spontaneous Interpersonal Synchronization.

    Science.gov (United States)

    Gipson, Christina L; Gorman, Jamie C; Hessler, Eric E

    2016-04-01

    Coordination with others is such a fundamental part of human activity that it can happen unintentionally. This unintentional coordination can manifest as synchronization and is observed in physical and human systems alike. We investigated the role of top-down influences (prior knowledge of the perceptual modality their partner is using) and bottom-up factors (perceptual modality combination) on spontaneous interpersonal synchronization. We examine this phenomena with respect to two different theoretical perspectives that differently emphasize top-down and bottom-up factors in interpersonal synchronization: joint-action/shared cognition theories and ecological-interactive theories. In an empirical study twelve dyads performed a finger oscillation task while attending to each other's movements through either visual, auditory, or visual and auditory perceptual modalities. Half of the participants were given prior knowledge of their partner's perceptual capabilities for coordinating across these different perceptual modality combinations. We found that the effect of top-down influence depends on the perceptual modality combination between two individuals. When people used the same perceptual modalities, top-down influence resulted in less synchronization and when people used different perceptual modalities, top-down influence resulted in more synchronization. Furthermore, persistence in the change in behavior as a result of having perceptual information about each other ('social memory') was stronger when this top-down influence was present.

  15. Thermal models of buildings. Determination of temperatures, heating and cooling loads. Theories, models and computer programs

    Energy Technology Data Exchange (ETDEWEB)

    Kaellblad, K

    1998-05-01

    The need to estimate indoor temperatures, heating or cooling load and energy requirements for buildings arises in many stages of a buildings life cycle, e.g. at the early layout stage, during the design of a building and for energy retrofitting planning. Other purposes are to meet the authorities requirements given in building codes. All these situations require good calculation methods. The main purpose of this report is to present the authors work with problems related to thermal models and calculation methods for determination of temperatures and heating or cooling loads in buildings. Thus the major part of the report deals with treatment of solar radiation in glazing systems, shading of solar and sky radiation and the computer program JULOTTA used to simulate the thermal behavior of rooms and buildings. Other parts of thermal models of buildings are more briefly discussed and included in order to give an overview of existing problems and available solutions. A brief presentation of how thermal models can be built up is also given and it is a hope that the report can be useful as an introduction to this part of building physics as well as during development of calculation methods and computer programs. The report may also serve as a help for the users of energy related programs. Independent of which method or program a user choose to work with it is his or her own responsibility to understand the limits of the tool, else wrong conclusions may be drawn from the results 52 refs, 22 figs, 4 tabs

  16. Force control theory and method of human load carrying exoskeleton suit

    CERN Document Server

    Yang, Zhiyong; Zhang, Jing; Gui, Lihua

    2017-01-01

    This book reports on the latest advances in concepts and further development of principal component analysis (PCA), discussing in detail a number of open problems related to dimensional reduction techniques and their extensions. It brings together research findings, previously scattered throughout many scientific journal papers worldwide, and presents them in a methodologically unified form. Offering vital insights into the subject matter in self-contained chapters that balance the theory and concrete applications, and focusing on open problems, it is essential reading for all researchers and practitioners with an interest in PCA.

  17. Athletic footwear: unsafe due to perceptual illusions.

    Science.gov (United States)

    Robbins, S E; Gouw, G J

    1991-02-01

    Modern athletic footwear provides remarkable plantar comfort when walking, running, or jumping. However, when injurious plantar loads elicit negligible perceived plantar discomfort, a perceptual illusion is created whereby perceived impact is lower than actual impact, which results in inadequate impact-moderating behavior and consequent injury. The objective of this study was to examine how plantar tactile (mechanical) events affect perceived plantar discomfort. Also, we evaluated the feasibility of a footwear safety standard we propose, which requires elimination of the above illusion. Twenty subjects gave numerical estimates of plantar discomfort produced by simulated locomotion (concurrent vertical (0.1-0.7 kg.cm-2) and horizontal (0.1-0.9 kg.cm-2) plantar loads), with the foot supported by either a smooth rigid surface or a rigid surface with 2 mm high rigid irregularities. Vertical or horizontal load alone evoked no discomfort (P greater than 0.05), whereas together, discomfort emanated from loads as low as 0.4 kg.cm-2. Irregularities heightened discomfort by a factor of 1.89. This suggests that the proposed safety standard is feasible, since compliance could be achieved simply by adding surface irregularities to insoles and by other changes that heighten localized plantar loads. However, until this standard is adhered to, it might be more appropriate to classify athletic footwear as "safety hazards" rather than "protective devices".

  18. Perceptual and Subliminal Communication: A Business Teacher's Dream.

    Science.gov (United States)

    Gratz, Elizabeth W.; Gratz, J. E.

    1983-01-01

    Aims to increase awareness of and sensitivity to perceptual and subliminal communication by focusing on selected applications of them in present day society. The basic theories are (1) communication is used to try to change a person's behavior and (2) it is being used primarily for deception rather than information. (JOW)

  19. Perceptual integration without conscious access.

    Science.gov (United States)

    Fahrenfort, Johannes J; van Leeuwen, Jonathan; Olivers, Christian N L; Hogendoorn, Hinze

    2017-04-04

    The visual system has the remarkable ability to integrate fragmentary visual input into a perceptually organized collection of surfaces and objects, a process we refer to as perceptual integration. Despite a long tradition of perception research, it is not known whether access to consciousness is required to complete perceptual integration. To investigate this question, we manipulated access to consciousness using the attentional blink. We show that, behaviorally, the attentional blink impairs conscious decisions about the presence of integrated surface structure from fragmented input. However, despite conscious access being impaired, the ability to decode the presence of integrated percepts remains intact, as shown through multivariate classification analyses of electroencephalogram (EEG) data. In contrast, when disrupting perception through masking, decisions about integrated percepts and decoding of integrated percepts are impaired in tandem, while leaving feedforward representations intact. Together, these data show that access consciousness and perceptual integration can be dissociated.

  20. [Development and effectiveness of a drug dosage calculation training program using cognitive loading theory based on smartphone application].

    Science.gov (United States)

    Kim, Myoung Soo; Park, Jung Ha; Park, Kyung Yeon

    2012-10-01

    This study was done to develop and evaluate a drug dosage calculation training program using cognitive loading theory based on a smartphone application. Calculation ability, dosage calculation related self-efficacy and anxiety were measured. A nonequivalent control group design was used. Smartphone application and a handout for self-study were developed and administered to the experimental group and only a handout was provided for control group. Intervention period was 4 weeks. Data were analyzed using descriptive analysis, χ²-test, t-test, and ANCOVA with the SPSS 18.0. The experimental group showed more 'self-efficacy for drug dosage calculation' than the control group (t=3.82, psmartphone application is effective in improving dosage calculation related self-efficacy and calculation ability. Further study should be done to develop additional interventions for reducing anxiety.

  1. Shock loading predictions from application of indicial theory to shock-turbulence interactions

    Science.gov (United States)

    Keefe, Laurence R.; Nixon, David

    1991-01-01

    A sequence of steps that permits prediction of some of the characteristics of the pressure field beneath a fluctuating shock wave from knowledge of the oncoming turbulent boundary layer is presented. The theory first predicts the power spectrum and pdf of the position and velocity of the shock wave, which are then used to obtain the shock frequency distribution, and the pdf of the pressure field, as a function of position within the interaction region. To test the validity of the crucial assumption of linearity, the indicial response of a normal shock is calculated from numerical simulation. This indicial response, after being fit by a simple relaxation model, is used to predict the shock position and velocity spectra, along with the shock passage frequency distribution. The low frequency portion of the shock spectra, where most of the energy is concentrated, is satisfactorily predicted by this method.

  2. Constructing knowledge through perceptual processes in making craft-art

    Directory of Open Access Journals (Sweden)

    Milla Ojala

    2013-10-01

    Full Text Available The focus of the study is on the knowledge that is constructed through perceptual processes during craft making in the context of the Finnish Basic Education in the Arts (BEA system. Craft studies in the BEA are defined as craft-art. The research method used is the grounded theory. The data consists of seven interviews and participant observations. Participants in the study are adolescents who study craft-art in the BEA system in Visual Art School, Aimo in Hämeenlinna. The aim of the article is to present, define and reflect on the concepts, properties and dimensions concerning perceptual processes that are discovered in this stage of the study following grounded theory procedures. The perceptual processes are an essential means of constructing knowledge in craft-art. Consequently, one aim of the study is to discuss how these processes are connected to various types of knowledge. The perceptual processes are described by seven concepts: imitative, anticipative, evaluative, experimental, emotional, temporal and bodily perceptions. They indicate on a conceptual level the characteristic of knowledge constructed through perceptual processes in craft-art. Further, theconcepts have several properties that can vary dimensionally between two qualities. The properties are activity, function and position. The dimensions of the properties vary from active to passive, formal to informal and internal to external. In conclusion, the concepts can describe a large range of incidents in different situations. They also seem to describe well the practice of  craft-art and there are several connections with pre-existing concepts of knowledge.Keywords: Craft, Knowledge, Perceptual process, Basic Education in the Arts, Grounded Theory 

  3. Perceptual Biases in Relation to Paranormal and Conspiracy Beliefs.

    Science.gov (United States)

    van Elk, Michiel

    2015-01-01

    Previous studies have shown that one's prior beliefs have a strong effect on perceptual decision-making and attentional processing. The present study extends these findings by investigating how individual differences in paranormal and conspiracy beliefs are related to perceptual and attentional biases. Two field studies were conducted in which visitors of a paranormal conducted a perceptual decision making task (i.e. the face/house categorization task; Experiment 1) or a visual attention task (i.e. the global/local processing task; Experiment 2). In the first experiment it was found that skeptics compared to believers more often incorrectly categorized ambiguous face stimuli as representing a house, indicating that disbelief rather than belief in the paranormal is driving the bias observed for the categorization of ambiguous stimuli. In the second experiment, it was found that skeptics showed a classical 'global-to-local' interference effect, whereas believers in conspiracy theories were characterized by a stronger 'local-to-global interference effect'. The present study shows that individual differences in paranormal and conspiracy beliefs are associated with perceptual and attentional biases, thereby extending the growing body of work in this field indicating effects of cultural learning on basic perceptual processes.

  4. Perceptual Biases in Relation to Paranormal and Conspiracy Beliefs.

    Directory of Open Access Journals (Sweden)

    Michiel van Elk

    Full Text Available Previous studies have shown that one's prior beliefs have a strong effect on perceptual decision-making and attentional processing. The present study extends these findings by investigating how individual differences in paranormal and conspiracy beliefs are related to perceptual and attentional biases. Two field studies were conducted in which visitors of a paranormal conducted a perceptual decision making task (i.e. the face/house categorization task; Experiment 1 or a visual attention task (i.e. the global/local processing task; Experiment 2. In the first experiment it was found that skeptics compared to believers more often incorrectly categorized ambiguous face stimuli as representing a house, indicating that disbelief rather than belief in the paranormal is driving the bias observed for the categorization of ambiguous stimuli. In the second experiment, it was found that skeptics showed a classical 'global-to-local' interference effect, whereas believers in conspiracy theories were characterized by a stronger 'local-to-global interference effect'. The present study shows that individual differences in paranormal and conspiracy beliefs are associated with perceptual and attentional biases, thereby extending the growing body of work in this field indicating effects of cultural learning on basic perceptual processes.

  5. Neural mechanisms underlying the induction and relief of perceptual curiosity

    Directory of Open Access Journals (Sweden)

    Marieke eJepma

    2012-02-01

    Full Text Available Curiosity is one of the most basic biological drives in both animals and humans, and has been identified as a key motive for learning and discovery. Despite the importance of curiosity and related behaviors, the topic has been largely neglected in human neuroscience; hence little is known about the neurobiological mechanisms underlying curiosity. We used functional magnetic resonance imaging (fMRI to investigate what happens in our brain during the induction and subsequent relief of perceptual curiosity. Our core findings were that (i the induction of perceptual curiosity, through the presentation of ambiguous visual input, activated the anterior insula and anterior cingulate cortex, brain regions sensitive to conflict and arousal; (ii the relief of perceptual curiosity, through visual disambiguation, activated regions of the striatum that have been related to reward processing; and (iii the relief of perceptual curiosity was associated with hippocampal activation and enhanced incidental memory. These findings provide the first demonstration of the neural basis of human perceptual curiosity. Our results provide neurobiological support for a classic psychological theory of curiosity, which holds that curiosity is an aversive condition of increased arousal whose termination is rewarding and facilitates memory.

  6. Perceptual learning: top to bottom.

    Science.gov (United States)

    Amitay, Sygal; Zhang, Yu-Xuan; Jones, Pete R; Moore, David R

    2014-06-01

    Perceptual learning has traditionally been portrayed as a bottom-up phenomenon that improves encoding or decoding of the trained stimulus. Cognitive skills such as attention and memory are thought to drive, guide and modulate learning but are, with notable exceptions, not generally considered to undergo changes themselves as a result of training with simple perceptual tasks. Moreover, shifts in threshold are interpreted as shifts in perceptual sensitivity, with no consideration for non-sensory factors (such as response bias) that may contribute to these changes. Accumulating evidence from our own research and others shows that perceptual learning is a conglomeration of effects, with training-induced changes ranging from the lowest (noise reduction in the phase locking of auditory signals) to the highest (working memory capacity) level of processing, and includes contributions from non-sensory factors that affect decision making even on a "simple" auditory task such as frequency discrimination. We discuss our emerging view of learning as a process that increases the signal-to-noise ratio associated with perceptual tasks by tackling noise sources and inefficiencies that cause performance bottlenecks, and present some implications for training populations other than young, smart, attentive and highly-motivated college students. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  7. The effect of implementing cognitive load theory-based design principles in virtual reality simulation training of surgical skills: a randomized controlled trial.

    Science.gov (United States)

    Andersen, Steven Arild Wuyts; Mikkelsen, Peter Trier; Konge, Lars; Cayé-Thomasen, Per; Sørensen, Mads Sølvsten

    2016-01-01

    Cognitive overload can inhibit learning, and cognitive load theory-based instructional design principles can be used to optimize learning situations. This study aims to investigate the effect of implementing cognitive load theory-based design principles in virtual reality simulation training of mastoidectomy. Eighteen novice medical students received 1 h of self-directed virtual reality simulation training of the mastoidectomy procedure randomized for standard instructions (control) or cognitive load theory-based instructions with a worked example followed by a problem completion exercise (intervention). Participants then completed two post-training virtual procedures for assessment and comparison. Cognitive load during the post-training procedures was estimated by reaction time testing on an integrated secondary task. Final-product analysis by two blinded expert raters was used to assess the virtual mastoidectomy performances. Participants in the intervention group had a significantly increased cognitive load during the post-training procedures compared with the control group (52 vs. 41 %, p  = 0.02). This was also reflected in the final-product performance: the intervention group had a significantly lower final-product score than the control group (13.0 vs. 15.4, p  virtual reality surgical simulation training of novices.

  8. An efficient approach for electric load forecasting using distributed ART (adaptive resonance theory) and HS-ARTMAP (Hyper-spherical ARTMAP network) neural network

    International Nuclear Information System (INIS)

    Cai, Yuan; Wang, Jian-zhou; Tang, Yun; Yang, Yu-chen

    2011-01-01

    This paper presents a neural network based on adaptive resonance theory, named distributed ART (adaptive resonance theory) and HS-ARTMAP (Hyper-spherical ARTMAP network), applied to the electric load forecasting problem. The distributed ART combines the stable fast learning capabilities of winner-take-all ART systems with the noise tolerance and code compression capabilities of multi-layer perceptions. The HS-ARTMAP, a hybrid of an RBF (Radial Basis Function)-network-like module which uses hyper-sphere basis function substitute the Gaussian basis function and an ART-like module, performs incremental learning capabilities in function approximation problem. The HS-ARTMAP only receives the compressed distributed coding processed by distributed ART to deal with the proliferation problem which ARTMAP (adaptive resonance theory map) architecture often encounters and still performs well in electric load forecasting. To demonstrate the performance of the methodology, data from New South Wales and Victoria in Australia are illustrated. Results show that the developed method is much better than the traditional BP and single HS-ARTMAP neural network. -- Research highlights: → The processing of the presented network is based on compressed distributed data. It's an innovation among the adaptive resonance theory architecture. → The presented network decreases the proliferation the Fuzzy ARTMAP architectures usually encounter. → The network on-line forecasts electrical load accurately, stably. → Both one-period and multi-period load forecasting are executed using data of different cities.

  9. Cognitive Load Theory and the Use of Worked Examples as an Instructional Strategy in Physics for Distance Learners: A Preliminary Study

    Science.gov (United States)

    Saw, Kim Guan

    2017-01-01

    This article revisits the cognitive load theory to explore the use of worked examples to teach a selected topic in a higher level undergraduate physics course for distance learners at the School of Distance Education, Universiti Sains Malaysia. With a break of several years from receiving formal education and having only minimum science…

  10. A Conceptual Paper on the Application of the Picture Word Inductive Model Using Bruner's Constructivist View of Learning and the Cognitive Load Theory

    Science.gov (United States)

    Jiang, Xuan; Perkins, Kyle

    2013-01-01

    Bruner's constructs of learning, specifically the structure of learning, spiral curriculum, and discovery learning, in conjunction with the Cognitive Load Theory, are used to evaluate the Picture Word Inductive Model (PWIM), an inquiry-oriented inductive language arts strategy designed to teach K-6 children phonics and spelling. The PWIM reflects…

  11. Working memory load and distraction: dissociable effects of visual maintenance and cognitive control.

    Science.gov (United States)

    Konstantinou, Nikos; Beal, Eleanor; King, Jean-Remi; Lavie, Nilli

    2014-10-01

    We establish a new dissociation between the roles of working memory (WM) cognitive control and visual maintenance in selective attention as measured by the efficiency of distractor rejection. The extent to which focused selective attention can prevent distraction has been shown to critically depend on the level and type of load involved in the task. High perceptual load that consumes perceptual capacity leads to reduced distractor processing, whereas high WM load that reduces WM ability to exert priority-based executive cognitive control over the task results in increased distractor processing (e.g., Lavie, Trends in Cognitive Sciences, 9(2), 75-82, 2005). WM also serves to maintain task-relevant visual representations, and such visual maintenance is known to recruit the same sensory cortices as those involved in perception (e.g., Pasternak & Greenlee, Nature Reviews Neuroscience, 6(2), 97-107, 2005). These findings led us to hypothesize that loading WM with visual maintenance would reduce visual capacity involved in perception, thus resulting in reduced distractor processing-similar to perceptual load and opposite to WM cognitive control load. Distractor processing was assessed in a response competition task, presented during the memory interval (or during encoding; Experiment 1a) of a WM task. Loading visual maintenance or encoding by increased set size for a memory sample of shapes, colors, and locations led to reduced distractor response competition effects. In contrast, loading WM cognitive control with verbal rehearsal of a random letter set led to increased distractor effects. These findings confirm load theory predictions and provide a novel functional distinction between the roles of WM maintenance and cognitive control in selective attention.

  12. Mutual information, perceptual independence, and holistic face perception.

    Science.gov (United States)

    Fitousi, Daniel

    2013-07-01

    The concept of perceptual independence is ubiquitous in psychology. It addresses the question of whether two (or more) dimensions are perceived independently. Several authors have proposed perceptual independence (or its lack thereof) as a viable measure of holistic face perception (Loftus, Oberg, & Dillon, Psychological Review 111:835-863, 2004; Wenger & Ingvalson, Learning, Memory, and Cognition 28:872-892, 2002). According to this notion, the processing of facial features occurs in an interactive manner. Here, I examine this idea from the perspective of two theories of perceptual independence: the multivariate uncertainty analysis (MUA; Garner & Morton, Definitions, models, and experimental paradigms. Psychological Bulletin 72:233-259, 1969), and the general recognition theory (GRT; Ashby & Townsend, Psychological Review 93:154-179, 1986). The goals of the study were to (1) introduce the MUA, (2) examine various possible relations between MUA and GRT using numerical simulations, and (3) apply the MUA to two consensual markers of holistic face perception(-)recognition of facial features (Farah, Wilson, Drain, & Tanaka, Psychological Review 105:482-498, 1998) and the composite face effect (Young, Hellawell, & Hay, Perception 16:747-759, 1987). The results suggest that facial holism is generated by violations of several types of perceptual independence. They highlight the important theoretical role played by converging operations in the study of holistic face perception.

  13. Perceptual Plasticity for Auditory Object Recognition

    Science.gov (United States)

    Heald, Shannon L. M.; Van Hedger, Stephen C.; Nusbaum, Howard C.

    2017-01-01

    In our auditory environment, we rarely experience the exact acoustic waveform twice. This is especially true for communicative signals that have meaning for listeners. In speech and music, the acoustic signal changes as a function of the talker (or instrument), speaking (or playing) rate, and room acoustics, to name a few factors. Yet, despite this acoustic variability, we are able to recognize a sentence or melody as the same across various kinds of acoustic inputs and determine meaning based on listening goals, expectations, context, and experience. The recognition process relates acoustic signals to prior experience despite variability in signal-relevant and signal-irrelevant acoustic properties, some of which could be considered as “noise” in service of a recognition goal. However, some acoustic variability, if systematic, is lawful and can be exploited by listeners to aid in recognition. Perceivable changes in systematic variability can herald a need for listeners to reorganize perception and reorient their attention to more immediately signal-relevant cues. This view is not incorporated currently in many extant theories of auditory perception, which traditionally reduce psychological or neural representations of perceptual objects and the processes that act on them to static entities. While this reduction is likely done for the sake of empirical tractability, such a reduction may seriously distort the perceptual process to be modeled. We argue that perceptual representations, as well as the processes underlying perception, are dynamically determined by an interaction between the uncertainty of the auditory signal and constraints of context. This suggests that the process of auditory recognition is highly context-dependent in that the identity of a given auditory object may be intrinsically tied to its preceding context. To argue for the flexible neural and psychological updating of sound-to-meaning mappings across speech and music, we draw upon examples

  14. Perceptual incongruence influences bistability and cortical activation

    NARCIS (Netherlands)

    Brouwer, G.J.; Tong, F.; Hagoort, P.; van Ee, R.

    2009-01-01

    We employed a parametric psychophysical design in combination with functional imaging to examine the influence of metric changes in perceptual incongruence on perceptual alternation rates and cortical responses. Subjects viewed a bistable stimulus defined by incongruent depth cues; bistability

  15. Iterative perceptual learning for social behavior synthesis

    NARCIS (Netherlands)

    de Kok, I.A.; Poppe, Ronald Walter; Heylen, Dirk K.J.

    We introduce Iterative Perceptual Learning (IPL), a novel approach to learn computational models for social behavior synthesis from corpora of human–human interactions. IPL combines perceptual evaluation with iterative model refinement. Human observers rate the appropriateness of synthesized

  16. Iterative Perceptual Learning for Social Behavior Synthesis

    NARCIS (Netherlands)

    de Kok, I.A.; Poppe, Ronald Walter; Heylen, Dirk K.J.

    We introduce Iterative Perceptual Learning (IPL), a novel approach for learning computational models for social behavior synthesis from corpora of human-human interactions. The IPL approach combines perceptual evaluation with iterative model refinement. Human observers rate the appropriateness of

  17. Perceptual learning modifies untrained pursuit eye movements

    OpenAIRE

    Szpiro, Sarit F. A.; Spering, Miriam; Carrasco, Marisa

    2014-01-01

    Perceptual learning improves detection and discrimination of relevant visual information in mature humans, revealing sensory plasticity. Whether visual perceptual learning affects motor responses is unknown. Here we implemented a protocol that enabled us to address this question. We tested a perceptual response (motion direction estimation, in which observers overestimate motion direction away from a reference) and a motor response (voluntary smooth pursuit eye movements). Perceptual training...

  18. Perceptual transparency from image deformation.

    Science.gov (United States)

    Kawabe, Takahiro; Maruya, Kazushi; Nishida, Shin'ya

    2015-08-18

    Human vision has a remarkable ability to perceive two layers at the same retinal locations, a transparent layer in front of a background surface. Critical image cues to perceptual transparency, studied extensively in the past, are changes in luminance or color that could be caused by light absorptions and reflections by the front layer, but such image changes may not be clearly visible when the front layer consists of a pure transparent material such as water. Our daily experiences with transparent materials of this kind suggest that an alternative potential cue of visual transparency is image deformations of a background pattern caused by light refraction. Although previous studies have indicated that these image deformations, at least static ones, play little role in perceptual transparency, here we show that dynamic image deformations of the background pattern, which could be produced by light refraction on a moving liquid's surface, can produce a vivid impression of a transparent liquid layer without the aid of any other visual cues as to the presence of a transparent layer. Furthermore, a transparent liquid layer perceptually emerges even from a randomly generated dynamic image deformation as long as it is similar to real liquid deformations in its spatiotemporal frequency profile. Our findings indicate that the brain can perceptually infer the presence of "invisible" transparent liquids by analyzing the spatiotemporal structure of dynamic image deformation, for which it uses a relatively simple computation that does not require high-level knowledge about the detailed physics of liquid deformation.

  19. Advancing Lie Detection by Inducing Cognitive Load on Liars: A Review of Relevant Theories and Techniques Guided by Lessons from Polygraph-Based Approaches

    Science.gov (United States)

    Walczyk, Jeffrey J.; Igou, Frank P.; Dixon, Alexa P.; Tcholakian, Talar

    2013-01-01

    This article critically reviews techniques and theories relevant to the emerging field of “lie detection by inducing cognitive load selectively on liars.” To help these techniques benefit from past mistakes, we start with a summary of the polygraph-based Controlled Question Technique (CQT) and the major criticisms of it made by the National Research Council (2003), including that it not based on a validated theory and administration procedures have not been standardized. Lessons from the more successful Guilty Knowledge Test are also considered. The critical review that follows starts with the presentation of models and theories offering insights for cognitive lie detection that can undergird theoretically load-inducing approaches. This is followed by evaluation of specific research-based, load-inducing proposals, especially for their susceptibility to rehearsal and other countermeasures. To help organize these proposals and suggest new direction for innovation and refinement, a theoretical taxonomy is presented based on the type of cognitive load induced in examinees (intrinsic or extraneous) and how open-ended the responses to test items are. Finally, four recommendations are proffered that can help researchers and practitioners to avert the corresponding mistakes with the CQT and yield new, valid cognitive lie detection technologies. PMID:23378840

  20. Theory Study and Application of the BP-ANN Method for Power Grid Short-Term Load Forecasting

    Institute of Scientific and Technical Information of China (English)

    Xia Hua; Gang Zhang; Jiawei Yang; Zhengyuan Li

    2015-01-01

    Aiming at the low accuracy problem of power system short⁃term load forecasting by traditional methods, a back⁃propagation artifi⁃cial neural network (BP⁃ANN) based method for short⁃term load forecasting is presented in this paper. The forecast points are re⁃lated to prophase adjacent data as well as the periodical long⁃term historical load data. Then the short⁃term load forecasting model of Shanxi Power Grid (China) based on BP⁃ANN method and correlation analysis is established. The simulation model matches well with practical power system load, indicating the BP⁃ANN method is simple and with higher precision and practicality.

  1. Investigation of a Neurocognitive Biomarker and of Methods to Mitigate Biases in Cognitive/Perceptual/Emotional Processing

    Science.gov (United States)

    2016-03-03

    Perceptual/ Emotional Processing Report Title Sustained unilateral hand clenching alters perceptual processing and affective/ motivational state...clenching on emotional / motivational state are in accord with, and have been interpreted as fitting, theories of cerebral lateralization of emotion ...of lateralization of emotional / motivation state (e.g.; Davidson, 2002), such that unilateral clenching of the left hand, presumed to activate the

  2. Cooling-load prediction by the combination of rough set theory and an artificial neural-network based on data-fusion technique

    International Nuclear Information System (INIS)

    Hou Zhijian; Lian Zhiwei; Yao Ye; Yuan Xinjian

    2006-01-01

    A novel method integrating rough sets (RS) theory and an artificial neural network (ANN) based on data-fusion technique is presented to forecast an air-conditioning load. Data-fusion technique is the process of combining multiple sensors data or related information to estimate or predict entity states. In this paper, RS theory is applied to find relevant factors to the load, which are used as inputs of an artificial neural-network to predict the cooling load. To improve the accuracy and enhance the robustness of load forecasting results, a general load-prediction model, by synthesizing multi-RSAN (MRAN), is presented so as to make full use of redundant information. The optimum principle is employed to deduce the weights of each RSAN model. Actual prediction results from a real air-conditioning system show that, the MRAN forecasting model is better than the individual RSAN and moving average (AMIMA) ones, whose relative error is within 4%. In addition, individual RSAN forecasting results are better than that of ARIMA

  3. Perceptual basis of evolving Western musical styles.

    Science.gov (United States)

    Rodriguez Zivic, Pablo H; Shifres, Favio; Cecchi, Guillermo A

    2013-06-11

    The brain processes temporal statistics to predict future events and to categorize perceptual objects. These statistics, called expectancies, are found in music perception, and they span a variety of different features and time scales. Specifically, there is evidence that music perception involves strong expectancies regarding the distribution of a melodic interval, namely, the distance between two consecutive notes within the context of another. The recent availability of a large Western music dataset, consisting of the historical record condensed as melodic interval counts, has opened new possibilities for data-driven analysis of musical perception. In this context, we present an analytical approach that, based on cognitive theories of music expectation and machine learning techniques, recovers a set of factors that accurately identifies historical trends and stylistic transitions between the Baroque, Classical, Romantic, and Post-Romantic periods. We also offer a plausible musicological and cognitive interpretation of these factors, allowing us to propose them as data-driven principles of melodic expectation.

  4. A High-Order Theory for the Analysis of Circular Cylindrical Composite Sandwich Shells with Transversely Compliant Core Subjected to External Loads

    DEFF Research Database (Denmark)

    Rahmani, Omid; Khalili, S.M.R.; Thomsen, Ole Thybo

    2012-01-01

    A new model based on the high order sandwich panel theory is proposed to study the effect of external loads on the free vibration of circular cylindrical composite sandwich shells with transversely compliant core, including also the calculation of the buckling loads. In the present model......, which is based on a 3D elasticity solution for the core material, can be used as a benchmark in future studies of the free vibration and buckling of circular cylindrical composite sandwich shells with a transversely compliant core....

  5. Anger as "seeing red": evidence for a perceptual association.

    Science.gov (United States)

    Fetterman, Adam K; Robinson, Michael D; Meier, Brian P

    2012-01-01

    Metaphor representation theory contends that people conceptualise their non-perceptual states (e.g., emotion concepts) in perceptual terms. The present research extends this theory to colour manipulations and discrete emotional representations. Two experiments (N = 265) examined whether a red font colour would facilitate anger conceptions, consistent with metaphors referring to anger to "seeing red". Evidence for an implicit anger-red association was robust and emotionally discrete in nature. Further, Experiment 2 examined the directionality of such associations and found that they were asymmetrical: Anger categorisations were faster when a red font colour was involved, but redness categorisations were not faster when an anger-related word was involved. Implications for multiple literatures are discussed.

  6. Divided attention disrupts perceptual encoding during speech recognition.

    Science.gov (United States)

    Mattys, Sven L; Palmer, Shekeila D

    2015-03-01

    Performing a secondary task while listening to speech has a detrimental effect on speech processing, but the locus of the disruption within the speech system is poorly understood. Recent research has shown that cognitive load imposed by a concurrent visual task increases dependency on lexical knowledge during speech processing, but it does not affect lexical activation per se. This suggests that "lexical drift" under cognitive load occurs either as a post-lexical bias at the decisional level or as a secondary consequence of reduced perceptual sensitivity. This study aimed to adjudicate between these alternatives using a forced-choice task that required listeners to identify noise-degraded spoken words with or without the addition of a concurrent visual task. Adding cognitive load increased the likelihood that listeners would select a word acoustically similar to the target even though its frequency was lower than that of the target. Thus, there was no evidence that cognitive load led to a high-frequency response bias. Rather, cognitive load seems to disrupt sublexical encoding, possibly by impairing perceptual acuity at the auditory periphery.

  7. Referenceless Prediction of Perceptual Fog Density and Perceptual Image Defogging.

    Science.gov (United States)

    Choi, Lark Kwon; You, Jaehee; Bovik, Alan Conrad

    2015-11-01

    We propose a referenceless perceptual fog density prediction model based on natural scene statistics (NSS) and fog aware statistical features. The proposed model, called Fog Aware Density Evaluator (FADE), predicts the visibility of a foggy scene from a single image without reference to a corresponding fog-free image, without dependence on salient objects in a scene, without side geographical camera information, without estimating a depth-dependent transmission map, and without training on human-rated judgments. FADE only makes use of measurable deviations from statistical regularities observed in natural foggy and fog-free images. Fog aware statistical features that define the perceptual fog density index derive from a space domain NSS model and the observed characteristics of foggy images. FADE not only predicts perceptual fog density for the entire image, but also provides a local fog density index for each patch. The predicted fog density using FADE correlates well with human judgments of fog density taken in a subjective study on a large foggy image database. As applications, FADE not only accurately assesses the performance of defogging algorithms designed to enhance the visibility of foggy images, but also is well suited for image defogging. A new FADE-based referenceless perceptual image defogging, dubbed DEnsity of Fog Assessment-based DEfogger (DEFADE) achieves better results for darker, denser foggy images as well as on standard foggy images than the state of the art defogging methods. A software release of FADE and DEFADE is available online for public use: http://live.ece.utexas.edu/research/fog/index.html.

  8. Missing a trick: Auditory load modulates conscious awareness in audition.

    Science.gov (United States)

    Fairnie, Jake; Moore, Brian C J; Remington, Anna

    2016-07-01

    In the visual domain there is considerable evidence supporting the Load Theory of Attention and Cognitive Control, which holds that conscious perception of background stimuli depends on the level of perceptual load involved in a primary task. However, literature on the applicability of this theory to the auditory domain is limited and, in many cases, inconsistent. Here we present a novel "auditory search task" that allows systematic investigation of the impact of auditory load on auditory conscious perception. An array of simultaneous, spatially separated sounds was presented to participants. On half the trials, a critical stimulus was presented concurrently with the array. Participants were asked to detect which of 2 possible targets was present in the array (primary task), and whether the critical stimulus was present or absent (secondary task). Increasing the auditory load of the primary task (raising the number of sounds in the array) consistently reduced the ability to detect the critical stimulus. This indicates that, at least in certain situations, load theory applies in the auditory domain. The implications of this finding are discussed both with respect to our understanding of typical audition and for populations with altered auditory processing. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  9. Perceptual learning modifies untrained pursuit eye movements.

    Science.gov (United States)

    Szpiro, Sarit F A; Spering, Miriam; Carrasco, Marisa

    2014-07-07

    Perceptual learning improves detection and discrimination of relevant visual information in mature humans, revealing sensory plasticity. Whether visual perceptual learning affects motor responses is unknown. Here we implemented a protocol that enabled us to address this question. We tested a perceptual response (motion direction estimation, in which observers overestimate motion direction away from a reference) and a motor response (voluntary smooth pursuit eye movements). Perceptual training led to greater overestimation and, remarkably, it modified untrained smooth pursuit. In contrast, pursuit training did not affect overestimation in either pursuit or perception, even though observers in both training groups were exposed to the same stimuli for the same time period. A second experiment revealed that estimation training also improved discrimination, indicating that overestimation may optimize perceptual sensitivity. Hence, active perceptual training is necessary to alter perceptual responses, and an acquired change in perception suffices to modify pursuit, a motor response. © 2014 ARVO.

  10. Evaluating the role of attention in the context of unconscious thought theory: differential impact of attentional scope and load on preference and memory.

    Science.gov (United States)

    Srinivasan, Narayanan; Mukherjee, Sumitava; Mishra, Maruti V; Kesarwani, Smriti

    2013-01-01

    Attention is a key process used to conceptualize and define modes of thought, but we lack information about the role of specific attentional processes on preferential choice and memory in multi-attribute decision making. In this study, we examine the role of attention based on two dimensions, attentional scope and load on choice preference strength and memory using a paradigm that arguably elicits unconscious thought. Scope of attention was manipulated by using global or local processing during distraction (Experiment 1) and before the information-encoding stage (Experiment 2). Load was manipulated by using the n-back task in Experiment 1. Results from Experiment 1 show that global processing or distributed attention during distraction results in stronger preference irrespective of load but better memory only at low cognitive load. Task difficulty or load did not have any effect on preference or memory. In Experiment 2, distributed attention before attribute encoding facilitated only memory but did not influence preference. Results show that attentional processes at different stages of processing like distraction and information-encoding influence decision making processes. Scope of attention not only influences preference and memory but the manner in which attentional scope influences them depends on both load and stage of information processing. The results indicate the important role of attention in processes critical for decision making and calls for a re-evaluation of the unconscious thought theory (UTT) and the need for reconceptualizing the role of attention.

  11. Evaluating the role of attention in the context of unconscious thought theory: Differential impact of attentional scope and load on preference and memory

    Directory of Open Access Journals (Sweden)

    Narayanan eSrinivasan

    2013-02-01

    Full Text Available Attention is a key process used to conceptualize and define modes of thought, but we lack information on the role of specific attentional processes on preferential choice and memory in multi-attribute decision making. In this study, we examine the role of attention based on two dimensions, attentional scope and load on choice preference strength and memory using a paradigm that arguably elicits unconscious thought. Scope of attention was manipulated by using global or local processing during distraction (Experiment 1 and before the information encoding stage (Experiment 2. Load was manipulated by using the n-back task in Experiment 1. Results from Experiment 1 show that global processing or distributed attention during distraction results in stronger preference irrespective of load but better memory only at low cognitive load. Task difficulty or load did not have any effect on preference or memory. In Experiment 2, distributed attention before attribute encoding facilitated only memory but did not influence preference. Results show that attentional processes at different stages of processing like distraction and information-encoding influence decision making processes. Scope of attention not only influences preference and memory but the manner in which attentional scope influences them depends on both load and stage of information processing. The results indicate the important role of attention in processes critical for decision making and calls for a re-evaluation of the unconscious thought theory (UTT and the need for reconceptualizing the role of attention.

  12. Perceptually Uniform Motion Space.

    Science.gov (United States)

    Birkeland, Asmund; Turkay, Cagatay; Viola, Ivan

    2014-11-01

    Flow data is often visualized by animated particles inserted into a flow field. The velocity of a particle on the screen is typically linearly scaled by the velocities in the data. However, the perception of velocity magnitude in animated particles is not necessarily linear. We present a study on how different parameters affect relative motion perception. We have investigated the impact of four parameters. The parameters consist of speed multiplier, direction, contrast type and the global velocity scale. In addition, we investigated if multiple motion cues, and point distribution, affect the speed estimation. Several studies were executed to investigate the impact of each parameter. In the initial results, we noticed trends in scale and multiplier. Using the trends for the significant parameters, we designed a compensation model, which adjusts the particle speed to compensate for the effect of the parameters. We then performed a second study to investigate the performance of the compensation model. From the second study we detected a constant estimation error, which we adjusted for in the last study. In addition, we connect our work to established theories in psychophysics by comparing our model to a model based on Stevens' Power Law.

  13. Visual training improves perceptual grouping based on basic stimulus features.

    Science.gov (United States)

    Kurylo, Daniel D; Waxman, Richard; Kidron, Rachel; Silverstein, Steven M

    2017-10-01

    Training on visual tasks improves performance on basic and higher order visual capacities. Such improvement has been linked to changes in connectivity among mediating neurons. We investigated whether training effects occur for perceptual grouping. It was hypothesized that repeated engagement of integration mechanisms would enhance grouping processes. Thirty-six participants underwent 15 sessions of training on a visual discrimination task that required perceptual grouping. Participants viewed 20 × 20 arrays of dots or Gabor patches and indicated whether the array appeared grouped as vertical or horizontal lines. Across trials stimuli became progressively disorganized, contingent upon successful discrimination. Four visual dimensions were examined, in which grouping was based on similarity in luminance, color, orientation, and motion. Psychophysical thresholds of grouping were assessed before and after training. Results indicate that performance in all four dimensions improved with training. Training on a control condition, which paralleled the discrimination task but without a grouping component, produced no improvement. In addition, training on only the luminance and orientation dimensions improved performance for those conditions as well as for grouping by color, on which training had not occurred. However, improvement from partial training did not generalize to motion. Results demonstrate that a training protocol emphasizing stimulus integration enhanced perceptual grouping. Results suggest that neural mechanisms mediating grouping by common luminance and/or orientation contribute to those mediating grouping by color but do not share resources for grouping by common motion. Results are consistent with theories of perceptual learning emphasizing plasticity in early visual processing regions.

  14. Predicting the Perceptual Consequences of Hidden Hearing Loss

    Directory of Open Access Journals (Sweden)

    Andrew J. Oxenham

    2016-12-01

    Full Text Available Recent physiological studies in several rodent species have revealed that permanent damage can occur to the auditory system after exposure to a noise that produces only a temporary shift in absolute thresholds. The damage has been found to occur in the synapses between the cochlea’s inner hair cells and the auditory nerve, effectively severing part of the connection between the ear and the brain. This synaptopathy has been termed hidden hearing loss because its effects are not thought to be revealed in standard clinical, behavioral, or physiological measures of absolute threshold. It is currently unknown whether humans suffer from similar deficits after noise exposure. Even if synaptopathy occurs in humans, it remains unclear what the perceptual consequences might be or how they should best be measured. Here, we apply a simple theoretical model, taken from signal detection theory, to provide some predictions for what perceptual effects could be expected for a given loss of synapses. Predictions are made for a number of basic perceptual tasks, including tone detection in quiet and in noise, frequency discrimination, level discrimination, and binaural lateralization. The model’s predictions are in line with the empirical observations that a 50% loss of synapses leads to changes in threshold that are too small to be reliably measured. Overall, the model provides a simple initial quantitative framework for understanding and predicting the perceptual effects of synaptopathy in humans.

  15. Perceptual consciousness overflows cognitive access.

    Science.gov (United States)

    Block, Ned

    2011-12-01

    One of the most important issues concerning the foundations of conscious perception centers on the question of whether perceptual consciousness is rich or sparse. The overflow argument uses a form of 'iconic memory' to argue that perceptual consciousness is richer (i.e., has a higher capacity) than cognitive access: when observing a complex scene we are conscious of more than we can report or think about. Recently, the overflow argument has been challenged both empirically and conceptually. This paper reviews the controversy, arguing that proponents of sparse perception are committed to the postulation of (i) a peculiar kind of generic conscious representation that has no independent rationale and (ii) an unmotivated form of unconscious representation that in some cases conflicts with what we know about unconscious representation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Perceptual Color Characterization of Cameras

    Directory of Open Access Journals (Sweden)

    Javier Vazquez-Corral

    2014-12-01

    Full Text Available Color camera characterization, mapping outputs from the camera sensors to an independent color space, such as \\(XYZ\\, is an important step in the camera processing pipeline. Until now, this procedure has been primarily solved by using a \\(3 \\times 3\\ matrix obtained via a least-squares optimization. In this paper, we propose to use the spherical sampling method, recently published by Finlayson al., to perform a perceptual color characterization. In particular, we search for the \\(3 \\times 3\\ matrix that minimizes three different perceptual errors, one pixel based and two spatially based. For the pixel-based case, we minimize the CIE \\(\\Delta E\\ error, while for the spatial-based case, we minimize both the S-CIELAB error and the CID error measure. Our results demonstrate an improvement of approximately 3for the \\(\\Delta E\\ error, 7& for the S-CIELAB error and 13% for the CID error measures.

  17. Cognitive Load Theory and the Use of Worked Examples as an Instructional Strategy in Physics for Distance Learners: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Kim Guan SAW

    2017-10-01

    Full Text Available This article revisits the cognitive load theory to explore the use of worked examples to teach a selected topic in a higher level undergraduate physics course for distance learners at the School of Distance Education, Universiti Sains Malaysia. With a break of several years from receiving formal education and having only minimum science background, distance learners need an appropriate instructional strategy for courses that require complex conceptualization and mathematical manipulations. As the working memory is limited, distance learners need to acquire domain specific knowledge in stages to lessen cognitive load. This article charts a learning task with a lower cognitive load to teach Fermi-Dirac distribution and demonstrates the use of sequential worked examples. Content taught in stages using worked examples can be presented as a form of didactic conversation to reduce transactional distance. This instructional strategy can be applied to similar challenging topics in other well-structured domains in a distance learning environment.

  18. Minimalist approach to perceptual interactions.

    Science.gov (United States)

    Lenay, Charles; Stewart, John

    2012-01-01

    WORK AIMED AT STUDYING SOCIAL COGNITION IN AN INTERACTIONIST PERSPECTIVE OFTEN ENCOUNTERS SUBSTANTIAL THEORETICAL AND METHODOLOGICAL DIFFICULTIES: identifying the significant behavioral variables; recording them without disturbing the interaction; and distinguishing between: (a) the necessary and sufficient contributions of each individual partner for a collective dynamics to emerge; (b) features which derive from this collective dynamics and escape from the control of the individual partners; and (c) the phenomena arising from this collective dynamics which are subsequently appropriated and used by the partners. We propose a minimalist experimental paradigm as a basis for this conceptual discussion: by reducing the sensory inputs to a strict minimum, we force a spatial and temporal deployment of the perceptual activities, which makes it possible to obtain a complete recording and control of the dynamics of interaction. After presenting the principles of this minimalist approach to perception, we describe a series of experiments on two major questions in social cognition: recognizing the presence of another intentional subject; and phenomena of imitation. In both cases, we propose explanatory schema which render an interactionist approach to social cognition clear and explicit. Starting from our earlier work on perceptual crossing we present a new experiment on the mechanisms of reciprocal recognition of the perceptual intentionality of the other subject: the emergent collective dynamics of the perceptual crossing can be appropriated by each subject. We then present an experimental study of opaque imitation (when the subjects cannot see what they themselves are doing). This study makes it possible to characterize what a properly interactionist approach to imitation might be. In conclusion, we draw on these results, to show how an interactionist approach can contribute to a fully social approach to social cognition.

  19. Comparison of the lifting-line free vortex wake method and the blade-element-momentum theory regarding the simulated loads of multi-MW wind turbines

    International Nuclear Information System (INIS)

    Hauptmann, S; Bülk, M; Cheng, P W; Schön, L; Erbslöh, S; Boorsma, K; Grasso, F; Kühn, M

    2014-01-01

    Design load simulations for wind turbines are traditionally based on the blade- element-momentum theory (BEM). The BEM approach is derived from a simplified representation of the rotor aerodynamics and several semi-empirical correction models. A more sophisticated approach to account for the complex flow phenomena on wind turbine rotors can be found in the lifting-line free vortex wake method. This approach is based on a more physics based representation, especially for global flow effects. This theory relies on empirical correction models only for the local flow effects, which are associated with the boundary layer of the rotor blades. In this paper the lifting-line free vortex wake method is compared to a state- of-the-art BEM formulation with regard to aerodynamic and aeroelastic load simulations of the 5MW UpWind reference wind turbine. Different aerodynamic load situations as well as standardised design load cases that are sensitive to the aeroelastic modelling are evaluated in detail. This benchmark makes use of the AeroModule developed by ECN, which has been coupled to the multibody simulation code SIMPACK

  20. Comparison of the lifting-line free vortex wake method and the blade-element-momentum theory regarding the simulated loads of multi-MW wind turbines

    Science.gov (United States)

    Hauptmann, S.; Bülk, M.; Schön, L.; Erbslöh, S.; Boorsma, K.; Grasso, F.; Kühn, M.; Cheng, P. W.

    2014-12-01

    Design load simulations for wind turbines are traditionally based on the blade- element-momentum theory (BEM). The BEM approach is derived from a simplified representation of the rotor aerodynamics and several semi-empirical correction models. A more sophisticated approach to account for the complex flow phenomena on wind turbine rotors can be found in the lifting-line free vortex wake method. This approach is based on a more physics based representation, especially for global flow effects. This theory relies on empirical correction models only for the local flow effects, which are associated with the boundary layer of the rotor blades. In this paper the lifting-line free vortex wake method is compared to a state- of-the-art BEM formulation with regard to aerodynamic and aeroelastic load simulations of the 5MW UpWind reference wind turbine. Different aerodynamic load situations as well as standardised design load cases that are sensitive to the aeroelastic modelling are evaluated in detail. This benchmark makes use of the AeroModule developed by ECN, which has been coupled to the multibody simulation code SIMPACK.

  1. A modification to linearized theory for prediction of pressure loadings on lifting surfaces at high supersonic Mach numbers and large angles of attack

    Science.gov (United States)

    Carlson, H. W.

    1979-01-01

    A new linearized-theory pressure-coefficient formulation was studied. The new formulation is intended to provide more accurate estimates of detailed pressure loadings for improved stability analysis and for analysis of critical structural design conditions. The approach is based on the use of oblique-shock and Prandtl-Meyer expansion relationships for accurate representation of the variation of pressures with surface slopes in two-dimensional flow and linearized-theory perturbation velocities for evaluation of local three-dimensional aerodynamic interference effects. The applicability and limitations of the modification to linearized theory are illustrated through comparisons with experimental pressure distributions for delta wings covering a Mach number range from 1.45 to 4.60 and angles of attack from 0 to 25 degrees.

  2. Fast-forward scaling theory for phase imprinting on a BEC: creation of a wave packet with uniform momentum density and loading to Bloch states without disturbance

    Science.gov (United States)

    Masuda, Shumpei; Nakamura, Katsuhiro; Nakahara, Mikio

    2018-02-01

    We study phase imprinting on Bose-Einstein condensates (BECs) with the fast-forward scaling theory revealing a nontrivial scaling property in quantum dynamics. We introduce a wave packet with uniform momentum density (WPUM) which has peculiar properties but is short-lived. The fast-forward scaling theory is applied to derive the driving potential for creation of the WPUMs in a predetermined time. Fast manipulation is essential for the creation of WPUMs because of the instability of the state. We also study loading of a BEC into a predetermined Bloch state in the lowest band from the ground state of a periodic potential. Controlled linear potential is not sufficient for creation of the Bloch state with large wavenumber because the change in the amplitude of the order parameter is not negligible. We derive the exact driving potential for creation of predetermined Bloch states using the obtained theory.

  3. The role of convexity in perceptual completion: beyond good continuation.

    Science.gov (United States)

    Liu, Z; Jacobs, D W; Basri, R

    1999-01-01

    Since the seminal work of the Gestalt psychologists, there has been great interest in understanding what factors determine the perceptual organization of images. While the Gestaltists demonstrated the significance of grouping cues such as similarity, proximity and good continuation, it has not been well understood whether their catalog of grouping cues is complete--in part due to the paucity of effective methodologies for examining the significance of various grouping cues. We describe a novel, objective method to study perceptual grouping of planar regions separated by an occluder. We demonstrate that the stronger the grouping between two such regions, the harder it will be to resolve their relative stereoscopic depth. We use this new method to call into question many existing theories of perceptual completion (Ullman, S. (1976). Biological Cybernetics, 25, 1-6; Shashua, A., & Ullman, S. (1988). 2nd International Conference on Computer Vision (pp. 321-327); Parent, P., & Zucker, S. (1989). IEEE Transactions on Pattern Analysis and Machine Intelligence, 11, 823-839; Kellman, P. J., & Shipley, T. F. (1991). Cognitive psychology, Liveright, New York; Heitger, R., & von der Heydt, R. (1993). A computational model of neural contour processing, figure-ground segregation and illusory contours. In Internal Conference Computer Vision (pp. 32-40); Mumford, D. (1994). Algebraic geometry and its applications, Springer, New York; Williams, L. R., & Jacobs, D. W. (1997). Neural Computation, 9, 837-858) that are based on Gestalt grouping cues by demonstrating that convexity plays a strong role in perceptual completion. In some cases convexity dominates the effects of the well known Gestalt cue of good continuation. While convexity has been known to play a role in figure/ground segmentation (Rubin, 1927; Kanizsa & Gerbino, 1976), this is the first demonstration of its importance in perceptual completion.

  4. Large deformation of uniaxially loaded slender microbeams on the basis of modified couple stress theory: Analytical solution and Galerkin-based method

    Science.gov (United States)

    Kiani, Keivan

    2017-09-01

    Large deformation regime of micro-scale slender beam-like structures subjected to axially pointed loads is of high interest to nanotechnologists and applied mechanics community. Herein, size-dependent nonlinear governing equations are derived by employing modified couple stress theory. Under various boundary conditions, analytical relations between axially applied loads and deformations are presented. Additionally, a novel Galerkin-based assumed mode method (AMM) is established to solve the highly nonlinear equations. In some particular cases, the predicted results by the analytical approach are also checked with those of AMM and a reasonably good agreement is reported. Subsequently, the key role of the material length scale on the load-deformation of microbeams is discussed and the deficiencies of the classical elasticity theory in predicting such a crucial mechanical behavior are explained in some detail. The influences of slenderness ratio and thickness of the microbeam on the obtained results are also examined. The present work could be considered as a pivotal step in better realizing the postbuckling behavior of nano-/micro- electro-mechanical systems consist of microbeams.

  5. Cerebellar tDCS dissociates the timing of perceptual decisions from perceptual change in speech

    NARCIS (Netherlands)

    Lametti, D.R.; Oostwoud Wijdenes, L.; Bonaiuto, J.; Bestmann, S.; Rothwell, J.C.

    2016-01-01

    Neuroimaging studies suggest that the cerebellum might play a role in both speech perception and speech perceptual learning. However, it remains unclear what this role is: does the cerebellum directly contribute to the perceptual decision? Or does it contribute to the timing of perceptual decisions?

  6. Dissociable Roles of Different Types of Working Memory Load in Visual Detection

    Science.gov (United States)

    Konstantinou, Nikos; Lavie, Nilli

    2013-01-01

    We contrasted the effects of different types of working memory (WM) load on detection. Considering the sensory-recruitment hypothesis of visual short-term memory (VSTM) within load theory (e.g., Lavie, 2010) led us to predict that VSTM load would reduce visual-representation capacity, thus leading to reduced detection sensitivity during maintenance, whereas load on WM cognitive control processes would reduce priority-based control, thus leading to enhanced detection sensitivity for a low-priority stimulus. During the retention interval of a WM task, participants performed a visual-search task while also asked to detect a masked stimulus in the periphery. Loading WM cognitive control processes (with the demand to maintain a random digit order [vs. fixed in conditions of low load]) led to enhanced detection sensitivity. In contrast, loading VSTM (with the demand to maintain the color and positions of six squares [vs. one in conditions of low load]) reduced detection sensitivity, an effect comparable with that found for manipulating perceptual load in the search task. The results confirmed our predictions and established a new functional dissociation between the roles of different types of WM load in the fundamental visual perception process of detection. PMID:23713796

  7. Biaxial bending of slender HSC columns and tubes filled with concrete under short- and long-term loads: I Theory

    Directory of Open Access Journals (Sweden)

    Jose A. Rodríguez-Gutiérrez

    2014-05-01

    Full Text Available An analytical method that calculates both the short- and long-term response of slender columns made of high-strength concrete (HSC and tubes filled with concrete with generalized end conditions and subjected to transverse loads along the span and axial load at the ends (causing a single or double curvature under uniaxial or biaxial bending is presented. The proposed method, which is an extension of a method previously developed by the authors, is capable of predicting not only the complete load-rotation and load-deflection curves (both the ascending and descending parts but also the maximum load capacity. The columns that can be analyzed include solid and hollow (rectangular, circular, oval, C-, T-, L-, or any arbitrary shape cross sections and columns made of circular and rectangular steel tubes filled with HSC. The fiber method is used to calculate the moment-curvature diagrams at different levels of the applied axial load (i.e., the M-P-φ curves, and the Gauss method of integration (for the sum of the contributions of the fibers parallel to the neutral axis is used to calculate the lateral rotations and deflections along the column span. Long-term effects, such as creep and shrinkage of the concrete, are also included. However, the effects of the shear deformations and torsion along the member are not included. The validity of the proposed method is presented in a companion paper and compared against the experimental results for over seventy column specimens reported in the technical literature by different researchers.

  8. Dynamics of individual perceptual decisions

    Science.gov (United States)

    Clark, Torin K.; Lu, Yue M.; Karmali, Faisal

    2015-01-01

    Perceptual decision making is fundamental to a broad range of fields including neurophysiology, economics, medicine, advertising, law, etc. Although recent findings have yielded major advances in our understanding of perceptual decision making, decision making as a function of time and frequency (i.e., decision-making dynamics) is not well understood. To limit the review length, we focus most of this review on human findings. Animal findings, which are extensively reviewed elsewhere, are included when beneficial or necessary. We attempt to put these various findings and data sets, which can appear to be unrelated in the absence of a formal dynamic analysis, into context using published models. Specifically, by adding appropriate dynamic mechanisms (e.g., high-pass filters) to existing models, it appears that a number of otherwise seemingly disparate findings from the literature might be explained. One hypothesis that arises through this dynamic analysis is that decision making includes phasic (high pass) neural mechanisms, an evidence accumulator and/or some sort of midtrial decision-making mechanism (e.g., peak detector and/or decision boundary). PMID:26467513

  9. Building online brand perceptual map.

    Science.gov (United States)

    Chiang, I-Ping; Lin, Chih-Ying; Wang, Kaisheng M

    2008-10-01

    Many companies have launched their products or services online as a new business focus, but only a few of them have survived the competition and made profits. The most important key to an online business's success is to create "brand value" for the customers. Although the concept of online brand has been discussed in previous studies, there is no empirical study on the measurement of online branding. As Web 2.0 emerges to be critical to online branding, the purpose of this study was to measure Taiwan's major Web sites with a number of personality traits to build a perceptual map for online brands. A pretest identified 10 most representative online brand perceptions. The results of the correspondence analysis showed five groups in the perceptual map. This study provided a practical view of the associations and similarities among online brands for potential alliance or branding strategies. The findings also suggested that brand perceptions can be used with identified consumer needs and behaviors to better position online services. The brand perception map in the study also contributed to a better understanding of the online brands in Taiwan.

  10. A Test of Attention Control Theory in Public Speaking: Cognitive Load Influences the Relationship between State Anxiety and Verbal Production

    Science.gov (United States)

    King, Paul E.; Finn, Amber N.

    2017-01-01

    This study investigated the relationship between public-speaking state anxiety (PSA) and verbal communication performance when delivering a speech. In Study 1, participants delivered an extemporaneous five-minute classroom speech behind a lectern, and in Study 2, to increase cognitive load, participants delivered an extemporaneous five-minute…

  11. An examination of resource-based and fit-based theories of stereotyping under cognitive load and fit

    NARCIS (Netherlands)

    Nolan, MA; Haslam, SA; Spears, R; Oakes, PJ

    1999-01-01

    Should stereotyping be characterised as an act of cognitive miserliness of one of rational meaning-seeking? This paper uses a cognitive load paradigm to investigate the adequacy of popular resource-based explanations of stereotyping in comparison to art alternative fit-based or meaning-based

  12. Perceptual Fusion in Humans and Machines

    NARCIS (Netherlands)

    A.A. Salah (Albert Ali); O. Tanrı dağ

    2008-01-01

    htmlabstractHumans perceive the world through different perceptual modalities, which are processed in the brain by modality-specific areas and structures. However, there also exist multimodal neurons and areas, specialized in integrating perceptual information to enhance or suppress brain response.

  13. Modelling the Perceptual Components of Loudspeaker Distortion

    DEFF Research Database (Denmark)

    Olsen, Sune L.; Agerkvist, Finn T.; MacDonald, Ewen

    2016-01-01

    While non-linear distortion in loudspeakers decreases audio quality, the perceptual consequences can vary substantially. This paper investigates the metric Rnonlin [1] which was developed to predict subjective measurements of sound quality in nonlinear systems. The generalisability of the metric...... the perceptual consequences of non-linear distortion....

  14. A Theoretical Analysis of the Perceptual Span based on SWIFT Simulations of the n + 2 Boundary Paradigm

    OpenAIRE

    Risse, Sarah; Hohenstein, Sven; Kliegl, Reinhold; Engbert, Ralf

    2014-01-01

    Eye-movement experiments suggest that the perceptual span during reading is larger than the fixated word, asymmetric around the fixation position, and shrinks in size contingent on the foveal processing load. We used the SWIFT model of eye-movement control during reading to test these hypotheses and their implications under the assumption of graded parallel processing of all words inside the perceptual span. Specifically, we simulated reading in the boundary paradigm and analysed the effects ...

  15. Determination of post-shakedown quantities of a pipe bend via the simplified theory of plastic zones compared with load history dependent incremental analysis

    Science.gov (United States)

    Vollrath, Bastian; Hübel, Hartwig

    2018-01-01

    The Simplified Theory of Plastic Zones (STPZ) may be used to determine post-shakedown quantities such as strain ranges and accumulated strains at plastic or elastic shakedown. The principles of the method are summarized. Its practical applicability is shown by the example of a pipe bend subjected to constant internal pressure along with cyclic in-plane bending or/and cyclic radial temperature gradient. The results are compared with incremental analyses performed step-by-step throughout the entire load history until the state of plastic shakedown is achieved.

  16. Creating an engaging and stimulating anatomy lecture environment using the Cognitive Load Theory-based Lecture Model: Students' experiences

    Directory of Open Access Journals (Sweden)

    Siti N.H. Hadie, PhD

    2018-04-01

    بير في نطاق التحفيز الذاتي. بالإضافة إلى ذلك، لمست مجموعة التدخل تجربة تعلم جيدة من المحاضرات. الاستنتاجات: حفزت القواعد الإرشادية بنجاح المشاركة المعرفية للطلبة وخبرة التعلم، مما يدل على التحفيز الناجح للموارد ذات الصلة للطلبة. تحفيز هذه الموارد المعرفية ضروري لنجاح المعالجة المعرفية خصوصا عند تعلم موضوع صعب كعلم التشريح. Abstract: Objective: There is a need to create a standard interactive anatomy lecture that can engage students in their learning process. This study investigated the impact of a new lecturing guideline, the Cognitive Load Theory-based Lecture Model (CLT-bLM, on students' cognitive engagement and motivation. Methods: A randomised controlled trial involving 197 participants from three institutions was conducted. The control group attended a freestyle lecture on the gross anatomy of the heart, delivered by a qualified anatomist from each institution. The intervention group attended a CLT-bLM-based lecture on a similar topic, delivered by the same lecturer, three weeks thereafter. The lecturers had attended a CLT-bLM workshop that allowed them to prepare for the CLT-bLM-based lecture over the course of three weeks. The students' ratings on their cognitive engagement and internal motivation were evaluated immediately after the lecture using a validated Learners' Engagement and Motivation Questionnaire. The differences between variables were analysed and the results were triangulated with the focus group discussion findings that explored students' experience while attending the lecture. Results: The intervention group has a significantly higher level of cognitive engagement than the control group; however, no significant difference in internal motivation score was found. In addition, the

  17. Elasticity Theory Solution of the Problem on Plane Bending of a Narrow Layered Cantilever Beam by Loads at Its Free End

    Science.gov (United States)

    Goryk, A. V.; Koval'chuk, S. B.

    2018-05-01

    An exact elasticity theory solution for the problem on plane bending of a narrow layered composite cantilever beam by tangential and normal loads distributed on its free end is presented. Components of the stress-strain state are found for the whole layers package by directly integrating differential equations of the plane elasticity theory problem by using an analytic representation of piecewise constant functions of the mechanical characteristics of layer materials. The continuous solution obtained is realized for a four-layer beam with account of kinematic boundary conditions simulating the rigid fixation of its one end. The solution obtained allows one to predict the strength and stiffness of composite cantilever beams and to construct applied analytical solutions for various problems on the elastic bending of layered beams.

  18. Perceptual grouping effects on cursor movement expectations.

    Science.gov (United States)

    Dorneich, Michael C; Hamblin, Christopher J; Lancaster, Jeff A; Olofinboba, Olu

    2014-05-01

    Two studies were conducted to develop an understanding of factors that drive user expectations when navigating between discrete elements on a display via a limited degree-of-freedom cursor control device. For the Orion Crew Exploration Vehicle spacecraft, a free-floating cursor with a graphical user interface (GUI) would require an unachievable level of accuracy due to expected acceleration and vibration conditions during dynamic phases of flight. Therefore, Orion program proposed using a "caged" cursor to "jump" from one controllable element (node) on the GUI to another. However, nodes are not likely to be arranged on a rectilinear grid, and so movements between nodes are not obvious. Proximity between nodes, direction of nodes relative to each other, and context features may all contribute to user cursor movement expectations. In an initial study, we examined user expectations based on the nodes themselves. In a second study, we examined the effect of context features on user expectations. The studies established that perceptual grouping effects influence expectations to varying degrees. Based on these results, a simple rule set was developed to support users in building a straightforward mental model that closely matches their natural expectations for cursor movement. The results will help designers of display formats take advantage of the natural context-driven cursor movement expectations of users to reduce navigation errors, increase usability, and decrease access time. The rules set and guidelines tie theory to practice and can be applied in environments where vibration or acceleration are significant, including spacecraft, aircraft, and automobiles.

  19. Empirical Support for Perceptual Conceptualism

    Directory of Open Access Journals (Sweden)

    Nicolás Alejandro Serrano

    2018-03-01

    Full Text Available The main objective of this paper is to show that perceptual conceptualism can be understood as an empirically meaningful position and, furthermore, that there is some degree of empirical support for its main theses. In order to do this, I will start by offering an empirical reading of the conceptualist position, and making three predictions from it. Then, I will consider recent experimental results from cognitive sciences that seem to point towards those predictions. I will conclude that, while the evidence offered by those experiments is far from decisive, it is enough not only to show that conceptualism is an empirically meaningful position but also that there is empirical support for it.

  20. Cortical Surround Interactions and Perceptual Salience via Natural Scene Statistics.

    Directory of Open Access Journals (Sweden)

    Ruben Coen-Cagli

    Full Text Available Spatial context in images induces perceptual phenomena associated with salience and modulates the responses of neurons in primary visual cortex (V1. However, the computational and ecological principles underlying contextual effects are incompletely understood. We introduce a model of natural images that includes grouping and segmentation of neighboring features based on their joint statistics, and we interpret the firing rates of V1 neurons as performing optimal recognition in this model. We show that this leads to a substantial generalization of divisive normalization, a computation that is ubiquitous in many neural areas and systems. A main novelty in our model is that the influence of the context on a target stimulus is determined by their degree of statistical dependence. We optimized the parameters of the model on natural image patches, and then simulated neural and perceptual responses on stimuli used in classical experiments. The model reproduces some rich and complex response patterns observed in V1, such as the contrast dependence, orientation tuning and spatial asymmetry of surround suppression, while also allowing for surround facilitation under conditions of weak stimulation. It also mimics the perceptual salience produced by simple displays, and leads to readily testable predictions. Our results provide a principled account of orientation-based contextual modulation in early vision and its sensitivity to the homogeneity and spatial arrangement of inputs, and lends statistical support to the theory that V1 computes visual salience.

  1. Interdisciplinary Adventures in Perceptual Ecology

    Science.gov (United States)

    Bocast, Christopher S.

    A portfolio dissertation that began as acoustic ecology and matured into perceptual ecology, centered on ecomusicology, bioacoustics, and translational audio-based media works with environmental perspectives. The place of music in Western eco-cosmology through time provides a basis for structuring an environmental history of human sound perception. That history suggests that music may stabilize human mental activity, and that an increased musical practice may be essential for the human project. An overview of recent antecedents preceding the emergence of acoustic ecology reveals structural foundations from 20th century culture that underpin modern sound studies. The contextual role that Aldo Leopold, Jacob von Uexkull, John Cage, Marshall McLuhan, and others played in anticipating the development of acoustic ecology as an interdiscipline is detailed. This interdisciplinary aspect of acoustic ecology is defined and defended, while new developments like soundscape ecology are addressed, though ultimately sound studies will need to embrace a broader concept of full-spectrum "sensory" or "perceptual" ecology. The bioacoustic fieldwork done on spawning sturgeon emphasized this necessity. That study yielded scientific recordings and spectrographic analyses of spawning sounds produced by lake sturgeon, Acipenser fulvescens, during reproduction in natural habitats in the Lake Winnebago watershed in Wisconsin. Recordings were made on the Wolf and Embarrass River during the 2011-2013 spawning seasons. Several specimens were dissected to investigate possible sound production mechanisms; no sonic musculature was found. Drumming sounds, ranging from 5 to 7 Hz fundamental frequency, verified the infrasonic nature of previously undocumented "sturgeon thunder". Other characteristic noises of sturgeon spawning including low-frequency rumbles and hydrodynamic sounds were identified. Intriguingly, high-frequency signals resembling electric organ discharges were discovered. These

  2. Attention induced neural response trade-off in retinotopic cortex under load.

    Science.gov (United States)

    Torralbo, Ana; Kelley, Todd A; Rees, Geraint; Lavie, Nilli

    2016-09-14

    The effects of perceptual load on visual cortex response to distractors are well established and various phenomena of 'inattentional blindness' associated with elimination of visual cortex response to unattended distractors, have been documented in tasks of high load. Here we tested an account for these effects in terms of a load-induced trade-off between target and distractor processing in retinotopic visual cortex. Participants were scanned using fMRI while performing a visual-search task and ignoring distractor checkerboards in the periphery. Retinotopic responses to target and distractors were assessed as a function of search load (comparing search set-sizes two, three and five). We found that increased load not only increased activity in frontoparietal network, but also had opposite effects on retinotopic responses to target and distractors. Target-related signals in areas V2-V3 linearly increased, while distractor response linearly decreased, with increased load. Critically, the slopes were equivalent for both load functions, thus demonstrating resource trade-off. Load effects were also found in displays with the same item number in the distractor hemisphere across different set sizes, thus ruling out local intrahemispheric interactions as the cause. Our findings provide new evidence for load theory proposals of attention resource sharing between target and distractor leading to inattentional blindness.

  3. Using listener-based perceptual features as intermediate representations in music information retrieval.

    Science.gov (United States)

    Friberg, Anders; Schoonderwaldt, Erwin; Hedblad, Anton; Fabiani, Marco; Elowsson, Anders

    2014-10-01

    The notion of perceptual features is introduced for describing general music properties based on human perception. This is an attempt at rethinking the concept of features, aiming to approach the underlying human perception mechanisms. Instead of using concepts from music theory such as tones, pitches, and chords, a set of nine features describing overall properties of the music was selected. They were chosen from qualitative measures used in psychology studies and motivated from an ecological approach. The perceptual features were rated in two listening experiments using two different data sets. They were modeled both from symbolic and audio data using different sets of computational features. Ratings of emotional expression were predicted using the perceptual features. The results indicate that (1) at least some of the perceptual features are reliable estimates; (2) emotion ratings could be predicted by a small combination of perceptual features with an explained variance from 75% to 93% for the emotional dimensions activity and valence; (3) the perceptual features could only to a limited extent be modeled using existing audio features. Results clearly indicated that a small number of dedicated features were superior to a "brute force" model using a large number of general audio features.

  4. Norm compliance affects perceptual decisions through modulation of a starting point bias.

    Science.gov (United States)

    Toelch, Ulf; Panizza, Folco; Heekeren, Hauke R

    2018-03-01

    Adaptive decisions in social contexts depend on both perceptual information and social expectations or norms. These are potentially in conflict when certain choices are beneficial for an individual, but societal rules mandate a different course of action. To resolve such a conflict, the reliability of information has to be balanced against potentially deleterious effects of non-compliance such as ostracism. In this study, we systematically investigated how interactions between perceptual and social influences affect decision-relevant cognitive processes. In a direction-of-motion discrimination task, participants received perceptual information alongside information on other players' choices. In addition, we created conflict scenarios where players' choices affected other participants' monetary rewards dependent on whether their choices were in line or against the opinion of the other players. Importantly, we altered the strength of this manipulation in two separate experiments by contrasting motivations of either preventing harm or providing a benefit to others. Behavioural analyses and computational models of perceptual decisions showed that participants successfully integrated perceptual with social information. Participants' reliance on social information was effectively modulated in conflict situations. Critically, these effects were augmented when the strength of social norms was increased, indexing conditions under which social norms effectively influence decisions. These results inform theories of social influence by providing an account of how higher order goals like social norm compliance affect perceptual decisions.

  5. The influence of cognitive load on spatial search performance.

    Science.gov (United States)

    Longstaffe, Kate A; Hood, Bruce M; Gilchrist, Iain D

    2014-01-01

    During search, executive function enables individuals to direct attention to potential targets, remember locations visited, and inhibit distracting information. In the present study, we investigated these executive processes in large-scale search. In our tasks, participants searched a room containing an array of illuminated locations embedded in the floor. The participants' task was to press the switches at the illuminated locations on the floor so as to locate a target that changed color when pressed. The perceptual salience of the search locations was manipulated by having some locations flashing and some static. Participants were more likely to search at flashing locations, even when they were explicitly informed that the target was equally likely to be at any location. In large-scale search, attention was captured by the perceptual salience of the flashing lights, leading to a bias to explore these targets. Despite this failure of inhibition, participants were able to restrict returns to previously visited locations, a measure of spatial memory performance. Participants were more able to inhibit exploration to flashing locations when they were not required to remember which locations had previously been visited. A concurrent digit-span memory task further disrupted inhibition during search, as did a concurrent auditory attention task. These experiments extend a load theory of attention to large-scale search, which relies on egocentric representations of space. High cognitive load on working memory leads to increased distractor interference, providing evidence for distinct roles for the executive subprocesses of memory and inhibition during large-scale search.

  6. Perceptual processing during trauma, priming and the development of intrusive memories

    Science.gov (United States)

    Sündermann, Oliver; Hauschildt, Marit; Ehlers, Anke

    2013-01-01

    Background Intrusive reexperiencing in posttraumatic stress disorder (PTSD) is commonly triggered by stimuli with perceptual similarity to those present during the trauma. Information processing theories suggest that perceptual processing during the trauma and enhanced perceptual priming contribute to the easy triggering of intrusive memories by these cues. Methods Healthy volunteers (N = 51) watched neutral and trauma picture stories on a computer screen. Neutral objects that were unrelated to the content of the stories briefly appeared in the interval between the pictures. Dissociation and data-driven processing (as indicators of perceptual processing) and state anxiety during the stories were assessed with self-report questionnaires. After filler tasks, participants completed a blurred object identification task to assess priming and a recognition memory task. Intrusive memories were assessed with telephone interviews 2 weeks and 3 months later. Results Neutral objects were more strongly primed if they occurred in the context of trauma stories than if they occurred during neutral stories, although the effect size was only moderate (ηp2=.08) and only significant when trauma stories were presented first. Regardless of story order, enhanced perceptual priming predicted intrusive memories at 2-week follow-up (N = 51), but not at 3 months (n = 40). Data-driven processing, dissociation and anxiety increases during the trauma stories also predicted intrusive memories. Enhanced perceptual priming and data-driven processing were associated with lower verbal intelligence. Limitations It is unclear to what extent these findings generalize to real-life traumatic events and whether they are specific to negative emotional events. Conclusions The results provide some support for the role of perceptual processing and perceptual priming in reexperiencing symptoms. PMID:23207970

  7. Application of porous-media theory to the investigation of water ADC changes in rabbit Achilles tendon caused by tensile loading

    Science.gov (United States)

    Wellen, J.; Helmer, K. G.; Grigg, P.; Sotak, C. H.

    2004-09-01

    The water apparent diffusion coefficient (ADC) in rabbit Achilles tendon is anisotropic, diffusion-time dependent, and changes as a function of tensile load. Water ADC changes of tendon under mechanical load are thought to be due to the extrusion of water from the more restricted tendon core to a relatively unrestricted bulk phase at the periphery (rim) of the tendon. Tensile loading may influence water ADC values by changing the spatial separation of restricting barriers (e.g., increasing the tendon fibril packing density). To explore this issue, we have applied porous-media theory to the investigation of water ADC changes in rabbit Achilles tendon under two different mechanical loading conditions (a baseline condition with a minimal tensile stress and a second in which the tensile stress was approximately 1 MPa). Diffusion sensitivity was applied in directions parallel and perpendicular to the long axis of the tendon. The short diffusion-time behavior of the resulting time-dependent ADC curves was used to indirectly infer information regarding the average surface area to volume ratio of the space available for molecular diffusion. From these values, we estimated a 40% reduction in volume available for diffusion in the perpendicular direction after tensile loading, but only a 10% reduction in the parallel direction. These differences are consistent with the known geometry of the tendon microstructure and suggest an increase in fibril packing density upon loading. The long diffusion-time behavior of the time-dependent ADC curves was used to indirectly infer the tortuosity of the diffusion pathways through the interstitial space. The tortuosity in the direction perpendicular to the tendon long axis was approximately 2.5 times greater than that in the parallel direction. Stimulated-echo measurement of the ADC values at longer diffusion times resulted in T1 spin editing of water with shorter T1 values (and correspondingly lower ADC values). The resulting increase in

  8. 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…

  9. Differential Deterrence: Studying Heterogeneity and Changes in Perceptual Deterrence among Serious Youthful Offenders

    Science.gov (United States)

    Loughran, Thomas A.; Piquero, Alex R.; Fagan, Jeffrey; Mulvey, Edward P.

    2012-01-01

    Perceptual deterrence has been an enduring focus of interest in criminology. Although recent research has generated important new insights about how risks, costs, and rewards of offending are perceived and internalized, there remain two specific limitations to advancing theories of deterrence: (a) the lack of panel data to show whether issues of…

  10. Semantic Features, Perceptual Expectations, and Frequency as Factors in the Learning of Polar Spatial Adjective Concepts.

    Science.gov (United States)

    Dunckley, Candida J. Lutes; Radtke, Robert C.

    Two semantic theories of word learning, a perceptual complexity hypothesis (H. Clark, 1970) and a quantitative complexity hypothesis (E. Clark, 1972) were tested by teaching 24 preschoolers and 16 college students CVC labels for five polar spatial adjective concepts having single word representations in English, and for three having no direct…

  11. Greater perceptual sensitivity to happy facial expression.

    Science.gov (United States)

    Maher, Stephen; Ekstrom, Tor; Chen, Yue

    2014-01-01

    Perception of subtle facial expressions is essential for social functioning; yet it is unclear if human perceptual sensitivities differ in detecting varying types of facial emotions. Evidence diverges as to whether salient negative versus positive emotions (such as sadness versus happiness) are preferentially processed. Here, we measured perceptual thresholds for the detection of four types of emotion in faces--happiness, fear, anger, and sadness--using psychophysical methods. We also evaluated the association of the perceptual performances with facial morphological changes between neutral and respective emotion types. Human observers were highly sensitive to happiness compared with the other emotional expressions. Further, this heightened perceptual sensitivity to happy expressions can be attributed largely to the emotion-induced morphological change of a particular facial feature (end-lip raise).

  12. Perceptual incongruence influences bistability and cortical activation.

    Directory of Open Access Journals (Sweden)

    Gijs Joost Brouwer

    Full Text Available We employed a parametric psychophysical design in combination with functional imaging to examine the influence of metric changes in perceptual incongruence on perceptual alternation rates and cortical responses. Subjects viewed a bistable stimulus defined by incongruent depth cues; bistability resulted from incongruence between binocular disparity and monocular perspective cues that specify different slants (slant rivalry. Psychophysical results revealed that perceptual alternation rates were positively correlated with the degree of perceived incongruence. Functional imaging revealed systematic increases in activity that paralleled the psychophysical results within anterior intraparietal sulcus, prior to the onset of perceptual alternations. We suggest that this cortical activity predicts the frequency of subsequent alternations, implying a putative causal role for these areas in initiating bistable perception. In contrast, areas implicated in form and depth processing (LOC and V3A were sensitive to the degree of slant, but failed to show increases in activity when these cues were in conflict.

  13. Perceptual learning and adult cortical plasticity.

    Science.gov (United States)

    Gilbert, Charles D; Li, Wu; Piech, Valentin

    2009-06-15

    The visual cortex retains the capacity for experience-dependent changes, or plasticity, of cortical function and cortical circuitry, throughout life. These changes constitute the mechanism of perceptual learning in normal visual experience and in recovery of function after CNS damage. Such plasticity can be seen at multiple stages in the visual pathway, including primary visual cortex. The manifestation of the functional changes associated with perceptual learning involve both long term modification of cortical circuits during the course of learning, and short term dynamics in the functional properties of cortical neurons. These dynamics are subject to top-down influences of attention, expectation and perceptual task. As a consequence, each cortical area is an adaptive processor, altering its function in accordance to immediate perceptual demands.

  14. Studying Real-World Perceptual Expertise

    Directory of Open Access Journals (Sweden)

    Jianhong eShen

    2014-08-01

    Full Text Available Significant insights into visual cognition have come from studying real-world perceptual expertise. Many have previously reviewed empirical findings and theoretical developments from this work. Here we instead provide a brief perspective on approaches, considerations, and challenges to studying real-world perceptual expertise. We discuss factors like choosing to use real-world versus artificial object domains of expertise, selecting a target domain of real-world perceptual expertise, recruiting experts, evaluating their level of expertise, and experimentally testing experts in the lab and online. Throughout our perspective, we highlight expert birding (also called birdwatching as an example, as it has been used as a target domain for over two decades in the perceptual expertise literature.

  15. Perceptual inference and autistic traits

    DEFF Research Database (Denmark)

    Skewes, Joshua; Jegindø, Else-Marie Elmholdt; Gebauer, Line

    2015-01-01

    Autistic people are better at perceiving details. Major theories explain this in terms of bottom-up sensory mechanisms, or in terms of top-down cognitive biases. Recently, it has become possible to link these theories within a common framework. This framework assumes that perception is implicit...

  16. Can Attention be Divided Between Perceptual Groups?

    Science.gov (United States)

    McCann, Robert S.; Foyle, David C.; Johnston, James C.; Hart, Sandra G. (Technical Monitor)

    1994-01-01

    Previous work using Head-Up Displays (HUDs) suggests that the visual system parses the HUD and the outside world into distinct perceptual groups, with attention deployed sequentially to first one group and then the other. New experiments show that both groups can be processed in parallel in a divided attention search task, even though subjects have just processed a stimulus in one perceptual group or the other. Implications for models of visual attention will be discussed.

  17. A perceptual study of Scottish dialects

    OpenAIRE

    Tichenor, Sydney

    2012-01-01

    Perceptual dialectology is dedicated to the formal study of folk linguistic perceptions. Through an amalgamation of social psychology, ethnography, dialectology, sociolinguistics, cultural geography and myriad other fields, perceptual dialectology provides a methodology to gain insight to overt folk language attitudes, knowledge of regional distribution, and the importance of language variation and change (Preston 1989, 1999a). This study conducts the first investigation of folk percept...

  18. Perceptual advertisement by the prey of stalking or ambushing predators.

    Science.gov (United States)

    Broom, Mark; Ruxton, Graeme D

    2012-12-21

    There has been previous theoretical explorations of the stability of signals by prey that they have detected a stalking or ambush predator, where such perceptual advertisement dissuades the predator from attacking. Here we use a game theoretical model to extend the theory to consider some empirically-motivated complexities: (i) many perceptual advertisement signals appear to have the potential to vary in intensity, (ii) higher intensity signals are likely to be most costly to produce, and (iii) some high-cost signals (such as staring directly at the predator) can only be utilised if the prey is very confident of the existence of a nearby predator (that is, there are reserved or unfakable signals). We demonstrate that these complexities still allow for stable signalling. However, we do not find solutions where prey use a range of signal intensities to signal different degrees of confidence in the proximity of a predator; with prey simply adopting a binary response of not signalling or always signalling at the same fixed level. However this fixed level will not always be the cheapest possible signal, and we predict that prey that require more certainty about proximity of a predator will use higher-cost signals. The availability of reserved signals does not prohibit the stability of signalling based on lower-cost signals, but we also find circumstances where only the reserved signal is used. We discuss the potential to empirically test our model predictions, and to develop theory further to allow perceptual advertisement to be combined with other signalling functions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Next Day Building Load Predictions based on Limited Input Features Using an On-Line Laterally Primed Adaptive Resonance Theory Artificial Neural Network.

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Christian Birk [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photovoltaic and Grid Integration Group; Robinson, Matt [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mechanical Engineering; Yasaei, Yasser [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering; Caudell, Thomas [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering; Martinez-Ramon, Manel [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering; Mammoli, Andrea [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mechanical Engineering

    2016-07-01

    Optimal integration of thermal energy storage within commercial building applications requires accurate load predictions. Several methods exist that provide an estimate of a buildings future needs. Methods include component-based models and data-driven algorithms. This work implemented a previously untested algorithm for this application that is called a Laterally Primed Adaptive Resonance Theory (LAPART) artificial neural network (ANN). The LAPART algorithm provided accurate results over a two month period where minimal historical data and a small amount of input types were available. These results are significant, because common practice has often overlooked the implementation of an ANN. ANN have often been perceived to be too complex and require large amounts of data to provide accurate results. The LAPART neural network was implemented in an on-line learning manner. On-line learning refers to the continuous updating of training data as time occurs. For this experiment, training began with a singe day and grew to two months of data. This approach provides a platform for immediate implementation that requires minimal time and effort. The results from the LAPART algorithm were compared with statistical regression and a component-based model. The comparison was based on the predictions linear relationship with the measured data, mean squared error, mean bias error, and cost savings achieved by the respective prediction techniques. The results show that the LAPART algorithm provided a reliable and cost effective means to predict the building load for the next day.

  20. Disruptive colouration and perceptual grouping.

    Science.gov (United States)

    Espinosa, Irene; Cuthill, Innes C

    2014-01-01

    Camouflage is the primary defence of many animals and includes multiple strategies that interfere with figure-ground segmentation and object recognition. While matching background colours and textures is widespread and conceptually straightforward, less well explored are the optical 'tricks', collectively called disruptive colouration, that exploit perceptual grouping mechanisms. Adjacent high contrast colours create false edges, but this is not sufficient for an object's shape to be broken up; some colours must blend with the background. We test the novel hypothesis that this will be particularly effective when the colour patches on the animal appear to belong to, not merely different background colours, but different background objects. We used computer-based experiments where human participants had to find cryptic targets on artificial backgrounds. Creating what appeared to be bi-coloured foreground objects on bi-coloured backgrounds, we generated colour boundaries that had identical local contrast but either lay within or between (illusory) objects. As predicted, error rates for targets matching what appeared to be different background objects were higher than for targets which had otherwise identical local contrast to the background but appeared to belong to single background objects. This provides evidence for disruptive colouration interfering with higher-level feature integration in addition to previously demonstrated low-level effects involving contour detection. In addition, detection was impeded in treatments where targets were on or in close proximity to multiple background colour or tone boundaries. This is consistent with other studies which show a deleterious influence of visual 'clutter' or background complexity on search.

  1. Disruptive colouration and perceptual grouping.

    Directory of Open Access Journals (Sweden)

    Irene Espinosa

    Full Text Available Camouflage is the primary defence of many animals and includes multiple strategies that interfere with figure-ground segmentation and object recognition. While matching background colours and textures is widespread and conceptually straightforward, less well explored are the optical 'tricks', collectively called disruptive colouration, that exploit perceptual grouping mechanisms. Adjacent high contrast colours create false edges, but this is not sufficient for an object's shape to be broken up; some colours must blend with the background. We test the novel hypothesis that this will be particularly effective when the colour patches on the animal appear to belong to, not merely different background colours, but different background objects. We used computer-based experiments where human participants had to find cryptic targets on artificial backgrounds. Creating what appeared to be bi-coloured foreground objects on bi-coloured backgrounds, we generated colour boundaries that had identical local contrast but either lay within or between (illusory objects. As predicted, error rates for targets matching what appeared to be different background objects were higher than for targets which had otherwise identical local contrast to the background but appeared to belong to single background objects. This provides evidence for disruptive colouration interfering with higher-level feature integration in addition to previously demonstrated low-level effects involving contour detection. In addition, detection was impeded in treatments where targets were on or in close proximity to multiple background colour or tone boundaries. This is consistent with other studies which show a deleterious influence of visual 'clutter' or background complexity on search.

  2. Perceptual Image Compression in Telemedicine

    Science.gov (United States)

    Watson, Andrew B.; Ahumada, Albert J., Jr.; Eckstein, Miguel; Null, Cynthia H. (Technical Monitor)

    1996-01-01

    The next era of space exploration, especially the "Mission to Planet Earth" will generate immense quantities of image data. For example, the Earth Observing System (EOS) is expected to generate in excess of one terabyte/day. NASA confronts a major technical challenge in managing this great flow of imagery: in collection, pre-processing, transmission to earth, archiving, and distribution to scientists at remote locations. Expected requirements in most of these areas clearly exceed current technology. Part of the solution to this problem lies in efficient image compression techniques. For much of this imagery, the ultimate consumer is the human eye. In this case image compression should be designed to match the visual capacities of the human observer. We have developed three techniques for optimizing image compression for the human viewer. The first consists of a formula, developed jointly with IBM and based on psychophysical measurements, that computes a DCT quantization matrix for any specified combination of viewing distance, display resolution, and display brightness. This DCT quantization matrix is used in most recent standards for digital image compression (JPEG, MPEG, CCITT H.261). The second technique optimizes the DCT quantization matrix for each individual image, based on the contents of the image. This is accomplished by means of a model of visual sensitivity to compression artifacts. The third technique extends the first two techniques to the realm of wavelet compression. Together these two techniques will allow systematic perceptual optimization of image compression in NASA imaging systems. Many of the image management challenges faced by NASA are mirrored in the field of telemedicine. Here too there are severe demands for transmission and archiving of large image databases, and the imagery is ultimately used primarily by human observers, such as radiologists. In this presentation I will describe some of our preliminary explorations of the applications

  3. Generation and Perceptual Implicit Memory: Different Generation Tasks Produce Different Effects on Perceptual Priming

    Science.gov (United States)

    Mulligan, Neil W.; Dew, Ilana T. Z.

    2009-01-01

    The generation manipulation has been critical in delineating differences between implicit and explicit memory. In contrast to past research, the present experiments indicate that generating from a rhyme cue produces as much perceptual priming as does reading. This is demonstrated for 3 visual priming tasks: perceptual identification, word-fragment…

  4. Pupil size tracks perceptual content and surprise.

    Science.gov (United States)

    Kloosterman, Niels A; Meindertsma, Thomas; van Loon, Anouk M; Lamme, Victor A F; Bonneh, Yoram S; Donner, Tobias H

    2015-04-01

    Changes in pupil size at constant light levels reflect the activity of neuromodulatory brainstem centers that control global brain state. These endogenously driven pupil dynamics can be synchronized with cognitive acts. For example, the pupil dilates during the spontaneous switches of perception of a constant sensory input in bistable perceptual illusions. It is unknown whether this pupil dilation only indicates the occurrence of perceptual switches, or also their content. Here, we measured pupil diameter in human subjects reporting the subjective disappearance and re-appearance of a physically constant visual target surrounded by a moving pattern ('motion-induced blindness' illusion). We show that the pupil dilates during the perceptual switches in the illusion and a stimulus-evoked 'replay' of that illusion. Critically, the switch-related pupil dilation encodes perceptual content, with larger amplitude for disappearance than re-appearance. This difference in pupil response amplitude enables prediction of the type of report (disappearance vs. re-appearance) on individual switches (receiver-operating characteristic: 61%). The amplitude difference is independent of the relative durations of target-visible and target-invisible intervals and subjects' overt behavioral report of the perceptual switches. Further, we show that pupil dilation during the replay also scales with the level of surprise about the timing of switches, but there is no evidence for an interaction between the effects of surprise and perceptual content on the pupil response. Taken together, our results suggest that pupil-linked brain systems track both the content of, and surprise about, perceptual events. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  5. Frequent video game players resist perceptual interference.

    Directory of Open Access Journals (Sweden)

    Aaron V Berard

    Full Text Available Playing certain types of video games for a long time can improve a wide range of mental processes, from visual acuity to cognitive control. Frequent gamers have also displayed generalized improvements in perceptual learning. In the Texture Discrimination Task (TDT, a widely used perceptual learning paradigm, participants report the orientation of a target embedded in a field of lines and demonstrate robust over-night improvement. However, changing the orientation of the background lines midway through TDT training interferes with overnight improvements in overall performance on TDT. Interestingly, prior research has suggested that this effect will not occur if a one-hour break is allowed in between the changes. These results have suggested that after training is over, it may take some time for learning to become stabilized and resilient against interference. Here, we tested whether frequent gamers have faster stabilization of perceptual learning compared to non-gamers and examined the effect of daily video game playing on interference of training of TDT with one background orientation on perceptual learning of TDT with a different background orientation. As a result, we found that non-gamers showed overnight performance improvement only on one background orientation, replicating previous results with the interference in TDT. In contrast, frequent gamers demonstrated overnight improvements in performance with both background orientations, suggesting that they are better able to overcome interference in perceptual learning. This resistance to interference suggests that video game playing not only enhances the amplitude and speed of perceptual learning but also leads to faster and/or more robust stabilization of perceptual learning.

  6. Frequent video game players resist perceptual interference.

    Science.gov (United States)

    Berard, Aaron V; Cain, Matthew S; Watanabe, Takeo; Sasaki, Yuka

    2015-01-01

    Playing certain types of video games for a long time can improve a wide range of mental processes, from visual acuity to cognitive control. Frequent gamers have also displayed generalized improvements in perceptual learning. In the Texture Discrimination Task (TDT), a widely used perceptual learning paradigm, participants report the orientation of a target embedded in a field of lines and demonstrate robust over-night improvement. However, changing the orientation of the background lines midway through TDT training interferes with overnight improvements in overall performance on TDT. Interestingly, prior research has suggested that this effect will not occur if a one-hour break is allowed in between the changes. These results have suggested that after training is over, it may take some time for learning to become stabilized and resilient against interference. Here, we tested whether frequent gamers have faster stabilization of perceptual learning compared to non-gamers and examined the effect of daily video game playing on interference of training of TDT with one background orientation on perceptual learning of TDT with a different background orientation. As a result, we found that non-gamers showed overnight performance improvement only on one background orientation, replicating previous results with the interference in TDT. In contrast, frequent gamers demonstrated overnight improvements in performance with both background orientations, suggesting that they are better able to overcome interference in perceptual learning. This resistance to interference suggests that video game playing not only enhances the amplitude and speed of perceptual learning but also leads to faster and/or more robust stabilization of perceptual learning.

  7. The influence of gender on entrepreneurial intention: The mediating role of perceptual factors

    Directory of Open Access Journals (Sweden)

    Carmen Camelo-Ordaz

    2016-10-01

    Full Text Available The empirical evidence devoted to analyze the impact of perceptual factors in explaining the differences in the entrepreneurial intention of men and women is still limited and not entirely conclusive (Shinnar et al., 2012; Wilson et al., 2009. This non-conclusive research is significantly more noteworthy when the analysis is focused on the entrepreneurial intention of men and women once they become entrepreneurs. Drawing on this gap and taking as starting point the premises of Social Feminist Theory, our paper aims to examine the mediating role of perceptual factors on the relationship between gender and entrepreneurial intention of non-entrepreneurs and entrepreneurs. Drawing on a sample provided by the Global Entrepreneurship Monitor Project of 21,697 Spanish non-entrepreneurs and 2899 Spanish entrepreneurs, our results have shown that, in general terms, perceptual factor fully mediate the relationship between gender and the entrepreneurial intention of non-entrepreneurs, whereas such mediating impact disappears when people become entrepreneurs.

  8. Cinematic innervation: the intuitive form of perception in the distracted perceptual field

    Directory of Open Access Journals (Sweden)

    Sungyong Ahn

    2013-09-01

    Full Text Available In “The Work of Art in the Age of Its Technological Reproducibility,” Walter Benjamin alluded that the human perceptual field in his time would become more distracted by the intervention of technologies, and so masses’ tactility activated by distraction would be more important in the mechanized perception. Regarding this historical situation, Benjamin anticipated that the new mode of mass perception would be organized through people's collective “innervation” to technologies. This article aims to contextualize this physiological term's cultural, technical, and political implications within various discourses about perception from the late 19th century physiologies to early 20th century film theories. Benjamin considers the tactility of people's potential to reconstruct the optical scheme of perception from the “flatness of screen” in which distances between viewers and perceived objects collapse. In a similar vein, the late 19th century's physiology reconceptualized perception in its relation not so much to the transcendental division of subject/object as to the sensual condition of a retina as “a single immanent plane.” From this perspective, perception is phenomena entailed by a body's contact to a sensual environment, so how sense inputs circulate in a neural network is a determinant for explaining perceptual processes. With regard to this paradigm change, the invention of cinema in the late 19th century was significant because it radically changed the composition of the perceptual field in two directions. Cinema introduced the virtualized perceptual fields on which sense circulations were completely controlled by the operation of camera. At the same time, the mediation of projectors in theaters reorganized viewers’ neural paths for perceptual innervation. As Hugo Münsterberg and Sergei Eisenstein's theories reflect, cinematic media's intervention in the perceptual field made it possible for masses’ collective

  9. ViA: a perceptual visualization assistant

    Science.gov (United States)

    Healey, Chris G.; St. Amant, Robert; Elhaddad, Mahmoud S.

    2000-05-01

    This paper describes an automated visualized assistant called ViA. ViA is designed to help users construct perceptually optical visualizations to represent, explore, and analyze large, complex, multidimensional datasets. We have approached this problem by studying what is known about the control of human visual attention. By harnessing the low-level human visual system, we can support our dual goals of rapid and accurate visualization. Perceptual guidelines that we have built using psychophysical experiments form the basis for ViA. ViA uses modified mixed-initiative planning algorithms from artificial intelligence to search of perceptually optical data attribute to visual feature mappings. Our perceptual guidelines are integrated into evaluation engines that provide evaluation weights for a given data-feature mapping, and hints on how that mapping might be improved. ViA begins by asking users a set of simple questions about their dataset and the analysis tasks they want to perform. Answers to these questions are used in combination with the evaluation engines to identify and intelligently pursue promising data-feature mappings. The result is an automatically-generated set of mappings that are perceptually salient, but that also respect the context of the dataset and users' preferences about how they want to visualize their data.

  10. Comparing perceptual and preferential decision making.

    Science.gov (United States)

    Dutilh, Gilles; Rieskamp, Jörg

    2016-06-01

    Perceptual and preferential decision making have been studied largely in isolation. Perceptual decisions are considered to be at a non-deliberative cognitive level and have an outside criterion that defines the quality of decisions. Preferential decisions are considered to be at a higher cognitive level and the quality of decisions depend on the decision maker's subjective goals. Besides these crucial differences, both types of decisions also have in common that uncertain information about the choice situation has to be processed before a decision can be made. The present work aims to acknowledge the commonalities of both types of decision making to lay bare the crucial differences. For this aim we examine perceptual and preferential decisions with a novel choice paradigm that uses the identical stimulus material for both types of decisions. This paradigm allows us to model the decisions and response times of both types of decisions with the same sequential sampling model, the drift diffusion model. The results illustrate that the different incentive structure in both types of tasks changes people's behavior so that they process information more efficiently and respond more cautiously in the perceptual as compared to the preferential task. These findings set out a perspective for further integration of perceptual and preferential decision making in a single ramework.

  11. Perceptual Grouping via Untangling Gestalt Principles

    DEFF Research Database (Denmark)

    Qi, Yonggang; Guo, Jun; Li, Yi

    2013-01-01

    the importance of Gestalt rules by solving a learning to rank problem, and formulate a multi-label graph-cuts algo- rithm to group image primitives while taking into account the learned Gestalt confliction. Our experiment results confirm the existence of Gestalt confliction in perceptual grouping and demonstrate...... confliction, i.e., the relative importance of each rule compared with another, remains unsolved. In this paper, we investigate the problem of perceptual grouping by quantifying the confliction among three commonly used rules: similarity, continuity and proximity. More specifically, we propose to quantify...... an improved performance when such a conflic- tion is accounted for via the proposed grouping algorithm. Finally, a novel cross domain image classification method is proposed by exploiting perceptual grouping as representation....

  12. Visible digital watermarking system using perceptual models

    Science.gov (United States)

    Cheng, Qiang; Huang, Thomas S.

    2001-03-01

    This paper presents a visible watermarking system using perceptual models. %how and why A watermark image is overlaid translucently onto a primary image, for the purposes of immediate claim of copyright, instantaneous recognition of owner or creator, or deterrence to piracy of digital images or video. %perceptual The watermark is modulated by exploiting combined DCT-domain and DWT-domain perceptual models. % so that the watermark is visually uniform. The resulting watermarked image is visually pleasing and unobtrusive. The location, size and strength of the watermark vary randomly with the underlying image. The randomization makes the automatic removal of the watermark difficult even though the algorithm is known publicly but the key to the random sequence generator. The experiments demonstrate that the watermarked images have pleasant visual effect and strong robustness. The watermarking system can be used in copyright notification and protection.

  13. Reproducibility of somatosensory spatial perceptual maps.

    Science.gov (United States)

    Steenbergen, Peter; Buitenweg, Jan R; Trojan, Jörg; Veltink, Peter H

    2013-02-01

    Various studies have shown subjects to mislocalize cutaneous stimuli in an idiosyncratic manner. Spatial properties of individual localization behavior can be represented in the form of perceptual maps. Individual differences in these maps may reflect properties of internal body representations, and perceptual maps may therefore be a useful method for studying these representations. For this to be the case, individual perceptual maps need to be reproducible, which has not yet been demonstrated. We assessed the reproducibility of localizations measured twice on subsequent days. Ten subjects participated in the experiments. Non-painful electrocutaneous stimuli were applied at seven sites on the lower arm. Subjects localized the stimuli on a photograph of their own arm, which was presented on a tablet screen overlaying the real arm. Reproducibility was assessed by calculating intraclass correlation coefficients (ICC) for the mean localizations of each electrode site and the slope and offset of regression models of the localizations, which represent scaling and displacement of perceptual maps relative to the stimulated sites. The ICCs of the mean localizations ranged from 0.68 to 0.93; the ICCs of the regression parameters were 0.88 for the intercept and 0.92 for the slope. These results indicate a high degree of reproducibility. We conclude that localization patterns of non-painful electrocutaneous stimuli on the arm are reproducible on subsequent days. Reproducibility is a necessary property of perceptual maps for these to reflect properties of a subject's internal body representations. Perceptual maps are therefore a promising method for studying body representations.

  14. Topographic generalization of tactile perceptual learning.

    Science.gov (United States)

    Harrar, Vanessa; Spence, Charles; Makin, Tamar R

    2014-02-01

    Perceptual learning can improve our sensory abilities. Understanding its underlying mechanisms, in particular, when perceptual learning generalizes, has become a focus of research and controversy. Specifically, there is little consensus regarding the extent to which tactile perceptual learning generalizes across fingers. We measured tactile orientation discrimination abilities on 4 fingers (index and middle fingers of both hands), using psychophysical measures, before and after 4 training sessions on 1 finger. Given the somatotopic organization of the hand representation in the somatosensory cortex, the topography of the cortical areas underlying tactile perceptual learning can be inferred from the pattern of generalization across fingers; only fingers sharing cortical representation with the trained finger ought to improve with it. Following training, performance improved not only for the trained finger but also for its adjacent and homologous fingers. Although these fingers were not exposed to training, they nevertheless demonstrated similar levels of learning as the trained finger. Conversely, the performance of the finger that was neither adjacent nor homologous to the trained finger was unaffected by training, despite the fact that our procedure was designed to enhance generalization, as described in recent visual perceptual learning research. This pattern of improved performance is compatible with previous reports of neuronal receptive fields (RFs) in the primary somatosensory cortex (SI) spanning adjacent and homologous digits. We conclude that perceptual learning rooted in low-level cortex can still generalize, and suggest potential applications for the neurorehabilitation of syndromes associated with maladaptive plasticity in SI. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  15. Dissociation of rapid response learning and facilitation in perceptual and conceptual networks of person recognition.

    Science.gov (United States)

    Valt, Christian; Klein, Christoph; Boehm, Stephan G

    2015-08-01

    Repetition priming is a prominent example of non-declarative memory, and it increases the accuracy and speed of responses to repeatedly processed stimuli. Major long-hold memory theories posit that repetition priming results from facilitation within perceptual and conceptual networks for stimulus recognition and categorization. Stimuli can also be bound to particular responses, and it has recently been suggested that this rapid response learning, not network facilitation, provides a sound theory of priming of object recognition. Here, we addressed the relevance of network facilitation and rapid response learning for priming of person recognition with a view to advance general theories of priming. In four experiments, participants performed conceptual decisions like occupation or nationality judgments for famous faces. The magnitude of rapid response learning varied across experiments, and rapid response learning co-occurred and interacted with facilitation in perceptual and conceptual networks. These findings indicate that rapid response learning and facilitation in perceptual and conceptual networks are complementary rather than competing theories of priming. Thus, future memory theories need to incorporate both rapid response learning and network facilitation as individual facets of priming. © 2014 The British Psychological Society.

  16. Perceptual Experience and Seeing-as

    Directory of Open Access Journals (Sweden)

    Daniel Enrique Kalpokas

    2015-07-01

    Full Text Available According to Rorty, Davidson and Brandom, to have an experience is to be caused by our senses to hold a perceptual belief. This article argues that the phenomenon of seeing-as cannot be explained by such a conception of perceptual experience. First, the notion of experience defended by the aforementioned authors is reconstructed. Second, the main features of what Wittgenstein called “seeing aspects” are briefly presented. Finally, several arguments are developed in order to support the main thesis of the article: seeing-as cannot be explained by the conception of experience defended by Rorty, Davidson and Brandom.

  17. Perceptual and Cognitive Impairments and Driving

    Science.gov (United States)

    Korner-Bitensky, Nicol; Coopersmith, Henry; Mayo, Nancy; Leblanc, Ginette; Kaizer, Franceen

    1990-01-01

    Perceptual and cognitive disorders that frequently accompany stroke and head injury influence an individual's ability to drive a motor vehicle. Canadian physicians are legally responsible for identifying patients who are potentially unsafe to drive and, if they fail to do so, may be held liable in a civil action suit. The authors review the guidelines for physicians evaluating a patient's fitness to drive after brain injury. They also examine the actions a physician should take when a patient with perceptual and cognitive problems wants to drive. Ultimately, by taking these actions, physicians will help to prevent driving accidents. PMID:21234047

  18. Do you see what we see? The complex effects of perceptual distance between leaders and teams.

    Science.gov (United States)

    Gibson, Cristina B; Cooper, Cecily D; Conger, Jay A

    2009-01-01

    Previous distance-related theories and concepts (e.g., social distance) have failed to address the sometimes wide disparity in perceptions between leaders and the teams they lead. Drawing from the extensive literature on teams, leadership, and cognitive models of social information processing, the authors develop the concept of leader-team perceptual distance, defined as differences between a leader and a team in perceptions of the same social stimulus. The authors investigate the effects of perceptual distance on team performance, operationalizing the construct with 3 distinct foci: goal accomplishment, constructive conflict, and decision-making autonomy. Analyzing leader, member, and customer survey responses for a large sample of teams, the authors demonstrate that perceptual distance between a leader and a team regarding goal accomplishment and constructive conflict have a nonlinear relationship with team performance. Greater perceptual differences are associated with decreases in team performance. Moreover, this effect is strongest when a team's perceptions are more positive than the leader's are (as opposed to the reverse). This pattern illustrates the pervasive effects that perceptions can have on team performance, highlighting the importance of developing awareness of perceptions in order to increase effectiveness. Implications for theory and practice are delineated. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

  19. Task-relevant perceptual features can define categories in visual memory too.

    Science.gov (United States)

    Antonelli, Karla B; Williams, Carrick C

    2017-11-01

    Although Konkle, Brady, Alvarez, and Oliva (2010, Journal of Experimental Psychology: General, 139(3), 558) claim that visual long-term memory (VLTM) is organized on underlying conceptual, not perceptual, information, visual memory results from visual search tasks are not well explained by this theory. We hypothesized that when viewing an object, any task-relevant visual information is critical to the organizational structure of VLTM. In two experiments, we examined the organization of VLTM by measuring the amount of retroactive interference created by objects possessing different combinations of task-relevant features. Based on task instructions, only the conceptual category was task relevant or both the conceptual category and a perceptual object feature were task relevant. Findings indicated that when made task relevant, perceptual object feature information, along with conceptual category information, could affect memory organization for objects in VLTM. However, when perceptual object feature information was task irrelevant, it did not contribute to memory organization; instead, memory defaulted to being organized around conceptual category information. These findings support the theory that a task-defined organizational structure is created in VLTM based on the relevance of particular object features and information.

  20. Perceptual learning is specific to the trained structure of information.

    Science.gov (United States)

    Cohen, Yamit; Daikhin, Luba; Ahissar, Merav

    2013-12-01

    What do we learn when we practice a simple perceptual task? Many studies have suggested that we learn to refine or better select the sensory representations of the task-relevant dimension. Here we show that learning is specific to the trained structural regularities. Specifically, when this structure is modified after training with a fixed temporal structure, performance regresses to pretraining levels, even when the trained stimuli and task are retained. This specificity raises key questions as to the importance of low-level sensory modifications in the learning process. We trained two groups of participants on a two-tone frequency discrimination task for several days. In one group, a fixed reference tone was consistently presented in the first interval (the second tone was higher or lower), and in the other group the same reference tone was consistently presented in the second interval. When following training, these temporal protocols were switched between groups, performance of both groups regressed to pretraining levels, and further training was needed to attain postlearning performance. ERP measures, taken before and after training, indicated that participants implicitly learned the temporal regularity of the protocol and formed an attentional template that matched the trained structure of information. These results are consistent with Reverse Hierarchy Theory, which posits that even the learning of simple perceptual tasks progresses in a top-down manner, hence can benefit from temporal regularities at the trial level, albeit at the potential cost that learning may be specific to these regularities.

  1. Prediction of crack growth direction by Strain Energy Sih's Theory on specimens SEN under tension-compression biaxial loading employing Genetic Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-MartInez R; Lugo-Gonzalez E; Urriolagoitia-Calderon G; Urriolagoitia-Sosa G; Hernandez-Gomez L H; Romero-Angeles B; Torres-San Miguel Ch, E-mail: rrodriguezm@ipn.mx, E-mail: urrio332@hotmail.com, E-mail: guiurri@hotmail.com, E-mail: luishector56@hotmail.com, E-mail: romerobeatriz98@hotmail.com, E-mail: napor@hotmail.com [INSTITUTO POLITECNICO NACIONAL Seccion de Estudios de Posgrado e Investigacion (SEPI), Escuela Superior de Ingenieria Mecanica y Electrica (ESIME), Edificio 5. 2do Piso, Unidad Profesional Adolfo Lopez Mateos ' Zacatenco' Col. Lindavista, C.P. 07738, Mexico, D.F. (Mexico)

    2011-07-19

    Crack growth direction has been studied in many ways. Particularly Sih's strain energy theory predicts that a fracture under a three-dimensional state of stress spreads in direction of the minimum strain energy density. In this work a study for angle of fracture growth was made, considering a biaxial stress state at the crack tip on SEN specimens. The stress state applied on a tension-compression SEN specimen is biaxial one on crack tip, as it can observed in figure 1. A solution method proposed to obtain a mathematical model considering genetic algorithms, which have demonstrated great capacity for the solution of many engineering problems. From the model given by Sih one can deduce the density of strain energy stored for unit of volume at the crack tip as dW = [1/2E({sigma}{sup 2}{sub x} + {sigma}{sup 2}{sub y}) - {nu}/E({sigma}{sub x}{sigma}{sub y})]dV (1). From equation (1) a mathematical deduction to solve in terms of {theta} of this case was developed employing Genetic Algorithms, where {theta} is a crack propagation direction in plane x-y. Steel and aluminium mechanical properties to modelled specimens were employed, because they are two of materials but used in engineering design. Obtained results show stable zones of fracture propagation but only in a range of applied loading.

  2. Prediction of crack growth direction by Strain Energy Sih's Theory on specimens SEN under tension-compression biaxial loading employing Genetic Algorithms

    International Nuclear Information System (INIS)

    Rodriguez-MartInez R; Lugo-Gonzalez E; Urriolagoitia-Calderon G; Urriolagoitia-Sosa G; Hernandez-Gomez L H; Romero-Angeles B; Torres-San Miguel Ch

    2011-01-01

    Crack growth direction has been studied in many ways. Particularly Sih's strain energy theory predicts that a fracture under a three-dimensional state of stress spreads in direction of the minimum strain energy density. In this work a study for angle of fracture growth was made, considering a biaxial stress state at the crack tip on SEN specimens. The stress state applied on a tension-compression SEN specimen is biaxial one on crack tip, as it can observed in figure 1. A solution method proposed to obtain a mathematical model considering genetic algorithms, which have demonstrated great capacity for the solution of many engineering problems. From the model given by Sih one can deduce the density of strain energy stored for unit of volume at the crack tip as dW = [1/2E(σ 2 x + σ 2 y ) - ν/E(σ x σy)]dV (1). From equation (1) a mathematical deduction to solve in terms of θ of this case was developed employing Genetic Algorithms, where θ is a crack propagation direction in plane x-y. Steel and aluminium mechanical properties to modelled specimens were employed, because they are two of materials but used in engineering design. Obtained results show stable zones of fracture propagation but only in a range of applied loading.

  3. Resistance to Interference of Olfactory Perceptual Learning

    Science.gov (United States)

    Stevenson, Richard J.; Case, Trevor I.; Tomiczek, Caroline

    2007-01-01

    Olfactory memory is especially persistent. The current study explored whether this applies to a form of perceptual learning, in which experience of an odor mixture results in greater judged similarity between its elements. Experiment 1A contrasted 2 forms of interference procedure, "compound" (mixture AW, followed by presentation of new mixtures…

  4. Infant Memory for Primitive Perceptual Features.

    Science.gov (United States)

    Adler, Scott A.

    Textons are elongated blobs of specific color, angular orientation, ends of lines, and crossings of line segments that are proposed to be the perceptual building blocks of the visual system. A study was conducted to explore the relative memorability of different types and arrangements of textons, exploring the time course for the discrimination…

  5. Understanding perceptual boundaries in laparoscopic surgery.

    Science.gov (United States)

    Lamata, Pablo; Gomez, Enrique J; Hernández, Félix Lamata; Oltra Pastor, Alfonso; Sanchez-Margallo, Francisco Miquel; Del Pozo Guerrero, Francisco

    2008-03-01

    Human perceptual capabilities related to the laparoscopic interaction paradigm are not well known. Its study is important for the design of virtual reality simulators, and for the specification of augmented reality applications that overcome current limitations and provide a supersensing to the surgeon. As part of this work, this article addresses the study of laparoscopic pulling forces. Two definitions are proposed to focalize the problem: the perceptual fidelity boundary, limit of human perceptual capabilities, and the Utile fidelity boundary, that encapsulates the perceived aspects actually used by surgeons to guide an operation. The study is then aimed to define the perceptual fidelity boundary of laparoscopic pulling forces. This is approached with an experimental design in which surgeons assess the resistance against pulling of four different tissues, which are characterized with both in vivo interaction forces and ex vivo tissue biomechanical properties. A logarithmic law of tissue consistency perception is found comparing subjective valorizations with objective parameters. A model of this perception is developed identifying what the main parameters are: the grade of fixation of the organ, the tissue stiffness, the amount of tissue bitten, and the organ mass being pulled. These results are a clear requirement analysis for the force feedback algorithm of a virtual reality laparoscopic simulator. Finally, some discussion is raised about the suitability of augmented reality applications around this surgical gesture.

  6. Perceptual processing of a complex auditory context

    DEFF Research Database (Denmark)

    Quiroga Martinez, David Ricardo; Hansen, Niels Christian; Højlund, Andreas

    The mismatch negativity (MMN) is a brain response elicited by deviants in a series of repetitive sounds. It reflects the perception of change in low-level sound features and reliably measures perceptual auditory memory. However, most MMN studies use simple tone patterns as stimuli, failing...

  7. Well-Founded Belief and Perceptual Justification

    DEFF Research Database (Denmark)

    Broncano-Berrocal, Fernando

    2016-01-01

    According to Alan Millar, justified beliefs are well-founded beliefs. Millar cashes out the notion of well-foundedness in terms of having an adequate reason to believe something and believing it for that reason. To make his account of justified belief compatible with perceptual justification he...

  8. Prior expectations facilitate metacognition for perceptual decision.

    Science.gov (United States)

    Sherman, M T; Seth, A K; Barrett, A B; Kanai, R

    2015-09-01

    The influential framework of 'predictive processing' suggests that prior probabilistic expectations influence, or even constitute, perceptual contents. This notion is evidenced by the facilitation of low-level perceptual processing by expectations. However, whether expectations can facilitate high-level components of perception remains unclear. We addressed this question by considering the influence of expectations on perceptual metacognition. To isolate the effects of expectation from those of attention we used a novel factorial design: expectation was manipulated by changing the probability that a Gabor target would be presented; attention was manipulated by instructing participants to perform or ignore a concurrent visual search task. We found that, independently of attention, metacognition improved when yes/no responses were congruent with expectations of target presence/absence. Results were modeled under a novel Bayesian signal detection theoretic framework which integrates bottom-up signal propagation with top-down influences, to provide a unified description of the mechanisms underlying perceptual decision and metacognition. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. 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

  10. Lexically guided perceptual learning in Mandarin Chinese

    NARCIS (Netherlands)

    Burchfield, L.A.; Luk, S.H.K.; Antoniou, M.; Cutler, A.

    2017-01-01

    Lexically guided perceptual learni ng refers to the use of lexical knowledge to retune sp eech categories and thereby adapt to a novel talker's pronunciation. This adaptation has been extensively documented, but primarily for segmental-based learning in English and Dutch. In languages with lexical

  11. Comparison and Contrast in Perceptual Categorization

    Science.gov (United States)

    Hampton, James A.; Estes, Zachary; Simmons, Claire L.

    2005-01-01

    People categorized pairs of perceptual stimuli that varied in both category membership and pairwise similarity. Experiments 1 and 2 showed categorization of 1 color of a pair to be reliably contrasted from that of the other. This similarity-based contrast effect occurred only when the context stimulus was relevant for the categorization of the…

  12. Perceptual Articulation in Three Middle Eastern Culture

    Science.gov (United States)

    Amir, Yehuda

    1975-01-01

    Noting that one would expect that members of cultural groups whose modes of child rearing foster individual autonomy would achieve more articulated perceptual functioning rather than persons reared in societies where conformity and emotional dependence are stressed, this article discusses a study which compared two Israeli sub-groups and two…

  13. Reliability in perceptual analysis of voice quality.

    Science.gov (United States)

    Bele, Irene Velsvik

    2005-12-01

    This study focuses on speaking voice quality in male teachers (n = 35) and male actors (n = 36), who represent untrained and trained voice users, because we wanted to investigate normal and supranormal voices. In this study, both substantial and methodologic aspects were considered. It includes a method for perceptual voice evaluation, and a basic issue was rater reliability. A listening group of 10 listeners, 7 experienced speech-language therapists, and 3 speech-language therapist students evaluated the voices by 15 vocal characteristics using VA scales. Two sets of voice signals were investigated: text reading (2 loudness levels) and sustained vowel (3 levels). The results indicated a high interrater reliability for most perceptual characteristics. Connected speech was evaluated more reliably, especially at the normal level, but both types of voice signals were evaluated reliably, although the reliability for connected speech was somewhat higher than for vowels. Experienced listeners tended to be more consistent in their ratings than did the student raters. Some vocal characteristics achieved acceptable reliability even with a smaller panel of listeners. The perceptual characteristics grouped in 4 factors reflected perceptual dimensions.

  14. Perceptual evaluation of different image fusion schemes

    NARCIS (Netherlands)

    Toet, A.; IJspeert, J.K.

    2001-01-01

    Human perceptual performance was tested with images of nighttime outdoor scenes. The scenes were registered both with a dual band (visual and near infrared) image intensified low-light CCD camera (DII) and with a thermal middle wavelength band (3-5 μm) infrared (IR) camera. Fused imagery was

  15. Toward a Unified Communication Theory.

    Science.gov (United States)

    McMillan, Saundra

    After discussing the nature of theory itself, the author explains her concept of the Unified Communication Theory, which rests on the assumption that there exists in all living structures a potential communication factor which is delimited by species and ontogeny. An organism develops "symbol fixation" at the level where its perceptual abilities…

  16. Grey scale, the 'crispening effect', and perceptual linearization

    NARCIS (Netherlands)

    Belaïd, N.; Martens, J.B.

    1998-01-01

    One way of optimizing a display is to maximize the number of distinguishable grey levels, which in turn is equivalent to perceptually linearizing the display. Perceptual linearization implies that equal steps in grey value evoke equal steps in brightness sensation. The key to perceptual

  17. Weight and see: Loading working memory improves incidental identification of irrelevant faces

    Directory of Open Access Journals (Sweden)

    David eCarmel

    2012-08-01

    Full Text Available Are task-irrelevant stimuli processed to a level enabling individual identification? This question is central both for perceptual processing models and for applied settings (e.g., eyewitness testimony. Lavie’s load theory proposes that working memory actively maintains attentional prioritization of relevant over irrelevant information. Loading working memory thus impairs attentional prioritization, leading to increased processing of task-irrelevant stimuli. Previous research has shown that increased working memory load leads to greater interference effects from response competing distractors. Here we test the novel prediction that increased processing of irrelevant stimuli under high working memory load should lead to a greater likelihood of incidental identification of entirely irrelevant stimuli. To test this, we asked participants to perform a word-categorization task while ignoring task-irrelevant images. The categorization task was performed during the retention interval of a working memory task with either low or high load (defined by memory set size. Following the final experimental trial, a surprise question assessed incidental identification of the irrelevant image. Loading working memory was found to improve identification of task-irrelevant faces, but not of building stimuli (shown in a separate experiment to be less distracting. These findings suggest that working memory plays a critical role in determining whether distracting stimuli will be subsequently identified.

  18. The activity in the anterior insulae is modulated by perceptual decision-making difficulty.

    Science.gov (United States)

    Lamichhane, Bidhan; Adhikari, Bhim M; Dhamala, Mukesh

    2016-07-07

    Previous neuroimaging studies provide evidence for the involvement of the anterior insulae (INSs) in perceptual decision-making processes. However, how the insular cortex is involved in integration of degraded sensory information to create a conscious percept of environment and to drive our behaviors still remains a mystery. In this study, using functional magnetic resonance imaging (fMRI) and four different perceptual categorization tasks in visual and audio-visual domains, we measured blood oxygen level dependent (BOLD) signals and examined the roles of INSs in easy and difficult perceptual decision-making. We created a varying degree of degraded stimuli by manipulating the task-specific stimuli in these four experiments to examine the effects of task difficulty on insular cortex response. We hypothesized that significantly higher BOLD response would be associated with the ambiguity of the sensory information and decision-making difficulty. In all of our experimental tasks, we found the INS activity consistently increased with task difficulty and participants' behavioral performance changed with the ambiguity of the presented sensory information. These findings support the hypothesis that the anterior insulae are involved in sensory-guided, goal-directed behaviors and their activities can predict perceptual load and task difficulty. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Striatal activation reflects urgency in perceptual decision making.

    Science.gov (United States)

    van Maanen, Leendert; Fontanesi, Laura; Hawkins, Guy E; Forstmann, Birte U

    2016-10-01

    Deciding between multiple courses of action often entails an increasing need to do something as time passes - a sense of urgency. This notion of urgency is not incorporated in standard theories of speeded decision making that assume information is accumulated until a critical fixed threshold is reached. Yet, it is hypothesized in novel theoretical models of decision making. In two experiments, we investigated the behavioral and neural evidence for an "urgency signal" in human perceptual decision making. Experiment 1 found that as the duration of the decision making process increased, participants made a choice based on less evidence for the selected option. Experiment 2 replicated this finding, and additionally found that variability in this effect across participants covaried with activation in the striatum. We conclude that individual differences in susceptibility to urgency are reflected by striatal activation. By dynamically updating a response threshold, the striatum is involved in signaling urgency in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Social anxiety under load: the effects of perceptual load in processing emotional faces

    OpenAIRE

    Soares, Sandra C.; Rocha, Marta; Neiva, Tiago; Rodrigues, Paulo; Silva, Carlos F.

    2015-01-01

    Previous studies in the social anxiety arena have shown an impaired attentional control system, similar to that found in trait anxiety. However, the effect of task demands on social anxiety in socially threatening stimuli, such as angry faces, remains unseen. In the present study, 54 university students scoring high and low in the Social Interaction and Performance Anxiety and Avoidance Scale (SIPAAS) questionnaire, participated in a target letter discrimination task while task-irrelevant fac...

  1. Differential effect of visual masking in perceptual categorization.

    Science.gov (United States)

    Hélie, Sébastien; Cousineau, Denis

    2015-06-01

    This article explores the visual information used to categorize stimuli drawn from a common stimulus space into verbal and nonverbal categories using 2 experiments. Experiment 1 explores the effect of target duration on verbal and nonverbal categorization using backward masking to interrupt visual processing. With categories equated for difficulty for long and short target durations, intermediate target duration shows an advantage for verbal categorization over nonverbal categorization. Experiment 2 tests whether the results of Experiment 1 can be explained by shorter target duration resulting in a smaller signal-to-noise ratio of the categorization stimulus. To test for this possibility, Experiment 2 used integration masking with the same stimuli, categories, and masks as Experiment 1 with a varying level of mask opacity. As predicted, low mask opacity yielded similar results to long target duration while high mask opacity yielded similar results to short target duration. Importantly, intermediate mask opacity produced an advantage for verbal categorization over nonverbal categorization, similar to intermediate target duration. These results suggest that verbal and nonverbal categorization are affected differently by manipulations affecting the signal-to-noise ratio of the stimulus, consistent with multiple-system theories of categorizations. The results further suggest that verbal categorization may be more digital (and more robust to low signal-to-noise ratio) while the information used in nonverbal categorization may be more analog (and less robust to lower signal-to-noise ratio). This article concludes with a discussion of how these new results affect the use of masking in perceptual categorization and multiple-system theories of perceptual category learning. (c) 2015 APA, all rights reserved).

  2. Approach Motivation as Incentive Salience: Perceptual Sources of Evidence in Relation to Positive Word Primes

    OpenAIRE

    Ode, Scott; Winters, Patricia L.; Robinson, Michael D.

    2011-01-01

    Four experiments (total N = 391) examined predictions derived from a biologically-based incentive salience theory of approach motivation. In all experiments, judgments indicative of enhanced perceptual salience were exaggerated in the context of positive, relative to neutral or negative, stimuli. In Experiments 1 and 2, positive words were judged to be of a larger size (Experiment 1) and led individuals to judge subsequently presented neutral objects as larger in size (Experiment 2). In Exper...

  3. Motivation alters response bias and neural activation patterns in a perceptual decision-making task.

    Science.gov (United States)

    Reckless, G E; Bolstad, I; Nakstad, P H; Andreassen, O A; Jensen, J

    2013-05-15

    Motivation has been demonstrated to affect individuals' response strategies in economic decision-making, however, little is known about how motivation influences perceptual decision-making behavior or its related neural activity. Given the important role motivation plays in shaping our behavior, a better understanding of this relationship is needed. A block-design, continuous performance, perceptual decision-making task where participants were asked to detect a picture of an animal among distractors was used during functional magnetic resonance imaging (fMRI). The effect of positive and negative motivation on sustained activity within regions of the brain thought to underlie decision-making was examined by altering the monetary contingency associated with the task. In addition, signal detection theory was used to investigate the effect of motivation on detection sensitivity, response bias and response time. While both positive and negative motivation resulted in increased sustained activation in the ventral striatum, fusiform gyrus, left dorsolateral prefrontal cortex (DLPFC) and ventromedial prefrontal cortex, only negative motivation resulted in the adoption of a more liberal, closer to optimal response bias. This shift toward a liberal response bias correlated with increased activation in the left DLPFC, but did not result in improved task performance. The present findings suggest that motivation alters aspects of the way perceptual decisions are made. Further, this altered response behavior is reflected in a change in left DLPFC activation, a region involved in the computation of perceptual decisions. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  4. Visual Perceptual Learning and its Specificity and Transfer: A New Perspective

    Directory of Open Access Journals (Sweden)

    Cong Yu

    2011-05-01

    Full Text Available Visual perceptual learning is known to be location and orientation specific, and is thus assumed to reflect the neuronal plasticity in the early visual cortex. However, in recent studies we created “Double training” and “TPE” procedures to demonstrate that these “fundamental” specificities of perceptual learning are in some sense artifacts and that learning can completely transfer to a new location or orientation. We proposed a rule-based learning theory to reinterpret perceptual learning and its specificity and transfer: A high-level decision unit learns the rules of performing a visual task through training. However, the learned rules cannot be applied to a new location or orientation automatically because the decision unit cannot functionally connect to new visual inputs with sufficient strength because these inputs are unattended or even suppressed during training. It is double training and TPE training that reactivate these new inputs, so that the functional connections can be strengthened to enable rule application and learning transfer. Currently we are investigating the properties of perceptual learning free from the bogus specificities, and the results provide some preliminary but very interesting insights into how training reshapes the functional connections between the high-level decision units and sensory inputs in the brain.

  5. Dynamics of Gestalt psychology (invited review of Perceptual Dynamics: Theoretical foundations and philosophical implications of Gestalt psychology by F. Sundqvist)

    NARCIS (Netherlands)

    Helm, P.A. van der

    2006-01-01

    In Perceptual Dynamics, Sundqvist argues that the early 20th-century Gestaltist ideas gain fresh relevance by recent developments in cognitive science, particularly by approaches that start from either dynamic systems theory or connectionism. In this review, it is argued that Sundqvist's book is a

  6. 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…

  7. Monocular depth effects on perceptual fading.

    Science.gov (United States)

    Hsu, Li-Chuan; Kramer, Peter; Yeh, Su-Ling

    2010-08-06

    After prolonged viewing, a static target among moving non-targets is perceived to repeatedly disappear and reappear. An uncrossed stereoscopic disparity of the target facilitates this Motion-Induced Blindness (MIB). Here we test whether monocular depth cues can affect MIB too, and whether they can also affect perceptual fading in static displays. Experiment 1 reveals an effect of interposition: more MIB when the target appears partially covered by, than when it appears to cover, its surroundings. Experiment 2 shows that the effect is indeed due to interposition and not to the target's contours. Experiment 3 induces depth with the watercolor illusion and replicates Experiment 1. Experiments 4 and 5 replicate Experiments 1 and 3 without the use of motion. Since almost any stimulus contains a monocular depth cue, we conclude that perceived depth affects perceptual fading in almost any stimulus, whether dynamic or static. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. A perceptual metric for photo retouching.

    Science.gov (United States)

    Kee, Eric; Farid, Hany

    2011-12-13

    In recent years, advertisers and magazine editors have been widely criticized for taking digital photo retouching to an extreme. Impossibly thin, tall, and wrinkle- and blemish-free models are routinely splashed onto billboards, advertisements, and magazine covers. The ubiquity of these unrealistic and highly idealized images has been linked to eating disorders and body image dissatisfaction in men, women, and children. In response, several countries have considered legislating the labeling of retouched photos. We describe a quantitative and perceptually meaningful metric of photo retouching. Photographs are rated on the degree to which they have been digitally altered by explicitly modeling and estimating geometric and photometric changes. This metric correlates well with perceptual judgments of photo retouching and can be used to objectively judge by how much a retouched photo has strayed from reality.

  9. Crossmodal Perceptual Learning and Sensory Substitution

    Directory of Open Access Journals (Sweden)

    Michael J Proulx

    2011-10-01

    Full Text Available A sensory substitution device for blind persons aims to provide the missing visual input by converting images into a form that another modality can perceive, such as sound. Here I will discuss the perceptual learning and attentional mechanisms necessary for interpreting sounds produced by a device (The vOICe in a visuospatial manner. Although some aspects of the conversion, such as relating vertical location to pitch, rely on natural crossmodal mappings, the extensive training required suggests that synthetic mappings are required to generalize perceptual learning to new objects and environments, and ultimately to experience visual qualia. Here I will discuss the effects of the conversion and training on perception and attention that demonstrate the synthetic nature of learning the crossmodal mapping. Sensorimotor experience may be required to facilitate learning, develop expertise, and to develop a form of synthetic synaesthesia.

  10. Sensory Load Incurs Conceptual Processing Costs

    Science.gov (United States)

    Vermeulen, Nicolas; Corneille, Olivier; Niedenthal, Paula M.

    2008-01-01

    Theories of grounded cognition propose that modal simulations underlie cognitive representation of concepts [Barsalou, L. W. (1999). "Perceptual symbol systems." "Behavioral and Brain Sciences, 22"(4), 577-660; Barsalou, L. W. (2008). "Grounded cognition." "Annual Review of Psychology, 59", 617-645]. Based…

  11. The Perceptual Basis of the Modality Effect in Multimedia Learning

    Science.gov (United States)

    Rummer, Ralf; Schweppe, Judith; Furstenberg, Anne; Scheiter, Katharina; Zindler, Antje

    2011-01-01

    Various studies have demonstrated an advantage of auditory over visual text modality when learning with texts and pictures. To explain this modality effect, two complementary assumptions are proposed by cognitive theories of multimedia learning: first, the visuospatial load hypothesis, which explains the modality effect in terms of visuospatial…

  12. Perceptual digital imaging methods and applications

    CERN Document Server

    Lukac, Rastislav

    2012-01-01

    Visual perception is a complex process requiring interaction between the receptors in the eye that sense the stimulus and the neural system and the brain that are responsible for communicating and interpreting the sensed visual information. This process involves several physical, neural, and cognitive phenomena whose understanding is essential to design effective and computationally efficient imaging solutions. Building on advances in computer vision, image and video processing, neuroscience, and information engineering, perceptual digital imaging greatly enhances the capabilities of tradition

  13. Implicit Recognition Based on Lateralized Perceptual Fluency

    OpenAIRE

    Vargas, Iliana M.; Voss, Joel L.; Paller, Ken A.

    2012-01-01

    In some circumstances, accurate recognition of repeated images in an explicit memory test is driven by implicit memory. We propose that this “implicit recognition” results from perceptual fluency that influences responding without awareness of memory retrieval. Here we examined whether recognition would vary if images appeared in the same or different visual hemifield during learning and testing. Kaleidoscope images were briefly presented left or right of fixation during divided-attention enc...

  14. Explaining seeing? Disentangling qualia from perceptual organization.

    Science.gov (United States)

    Ibáñez, Agustin; Bekinschtein, Tristan

    2010-09-01

    Abstract Visual perception and integration seem to play an essential role in our conscious phenomenology. Relatively local neural processing of reentrant nature may explain several visual integration processes (feature binding or figure-ground segregation, object recognition, inference, competition), even without attention or cognitive control. Based on the above statements, should the neural signatures of visual integration (via reentrant process) be non-reportable phenomenological qualia? We argue that qualia are not required to understand this perceptual organization.

  15. Space and time in perceptual causality

    Directory of Open Access Journals (Sweden)

    Benjamin Straube

    2010-04-01

    Full Text Available Inferring causality is a fundamental feature of human cognition that allows us to theorize about and predict future states of the world. Michotte suggested that humans automatically perceive causality based on certain perceptual features of events. However, individual differences in judgments of perceptual causality cast doubt on Michotte’s view. To gain insights in the neural basis of individual difference in the perception of causality, our participants judged causal relationships in animations of a blue ball colliding with a red ball (a launching event while fMRI-data were acquired. Spatial continuity and temporal contiguity were varied parametrically in these stimuli. We did not find consistent brain activation differences between trials judged as caused and those judged as non-caused, making it unlikely that humans have universal instantiation of perceptual causality in the brain. However, participants were slower to respond to and showed greater neural activity for violations of causality, suggesting that humans are biased to expect causal relationships when moving objects appear to interact. Our participants demonstrated considerable individual differences in their sensitivity to spatial and temporal characteristics in perceiving causality. These qualitative differences in sensitivity to time or space in perceiving causality were instantiated in individual differences in activation of the left basal ganglia or right parietal lobe, respectively. Thus, the perception that the movement of one object causes the movement of another is triggered by elemental spatial and temporal sensitivities, which themselves are instantiated in specific distinct neural networks.

  16. Chromatic Perceptual Learning but No Category Effects without Linguistic Input.

    Science.gov (United States)

    Grandison, Alexandra; Sowden, Paul T; Drivonikou, Vicky G; Notman, Leslie A; Alexander, Iona; Davies, Ian R L

    2016-01-01

    Perceptual learning involves an improvement in perceptual judgment with practice, which is often specific to stimulus or task factors. Perceptual learning has been shown on a range of visual tasks but very little research has explored chromatic perceptual learning. Here, we use two low level perceptual threshold tasks and a supra-threshold target detection task to assess chromatic perceptual learning and category effects. Experiment 1 investigates whether chromatic thresholds reduce as a result of training and at what level of analysis learning effects occur. Experiment 2 explores the effect of category training on chromatic thresholds, whether training of this nature is category specific and whether it can induce categorical responding. Experiment 3 investigates the effect of category training on a higher level, lateralized target detection task, previously found to be sensitive to category effects. The findings indicate that performance on a perceptual threshold task improves following training but improvements do not transfer across retinal location or hue. Therefore, chromatic perceptual learning is category specific and can occur at relatively early stages of visual analysis. Additionally, category training does not induce category effects on a low level perceptual threshold task, as indicated by comparable discrimination thresholds at the newly learned hue boundary and adjacent test points. However, category training does induce emerging category effects on a supra-threshold target detection task. Whilst chromatic perceptual learning is possible, learnt category effects appear to be a product of left hemisphere processing, and may require the input of higher level linguistic coding processes in order to manifest.

  17. Audiovisual speech perception development at varying levels of perceptual processing.

    Science.gov (United States)

    Lalonde, Kaylah; Holt, Rachael Frush

    2016-04-01

    This study used the auditory evaluation framework [Erber (1982). Auditory Training (Alexander Graham Bell Association, Washington, DC)] to characterize the influence of visual speech on audiovisual (AV) speech perception in adults and children at multiple levels of perceptual processing. Six- to eight-year-old children and adults completed auditory and AV speech perception tasks at three levels of perceptual processing (detection, discrimination, and recognition). The tasks differed in the level of perceptual processing required to complete them. Adults and children demonstrated visual speech influence at all levels of perceptual processing. Whereas children demonstrated the same visual speech influence at each level of perceptual processing, adults demonstrated greater visual speech influence on tasks requiring higher levels of perceptual processing. These results support previous research demonstrating multiple mechanisms of AV speech processing (general perceptual and speech-specific mechanisms) with independent maturational time courses. The results suggest that adults rely on both general perceptual mechanisms that apply to all levels of perceptual processing and speech-specific mechanisms that apply when making phonetic decisions and/or accessing the lexicon. Six- to eight-year-old children seem to rely only on general perceptual mechanisms across levels. As expected, developmental differences in AV benefit on this and other recognition tasks likely reflect immature speech-specific mechanisms and phonetic processing in children.

  18. A Residential Area Extraction Method for High Resolution Remote Sensing Imagery by Using Visual Saliency and Perceptual Organization

    Directory of Open Access Journals (Sweden)

    CHEN Yixiang

    2017-12-01

    Full Text Available Inspired by human visual cognitive mechanism,a method of residential area extraction from high-resolution remote sensing images was proposed based on visual saliency and perceptual organization. Firstly,the data field theory of cognitive physics was introduced to model the visual saliency and the candidate residential areas were produced by adaptive thresholding. Then,the exact residential areas were obtained and refined by perceptual organization based on the high-frequency features of multi-scale wavelet transform. Finally,the validity of the proposed method was verified by experiments conducted on ZY-3 and Quickbird image data sets.

  19. High working memory load leads to more Ebbinghaus illusion

    OpenAIRE

    De Fockert, J. W.; Wu, Si

    2009-01-01

    The evidence that distractor processing increases with greater load on working memory has come mainly from Stroop-type interference tasks, making it difficult to establish whether cognitive load affects distractor processing at the perceptual level or during response selection. We measured the Ebbinghaus illusion under varying levels of working memory load to test whether cognitive control is also relevant for preventing processing of distractors that do not produce any response conflict, and...

  20. Beta oscillations define discrete perceptual cycles in the somatosensory domain.

    Science.gov (United States)

    Baumgarten, Thomas J; Schnitzler, Alfons; Lange, Joachim

    2015-09-29

    Whether seeing a movie, listening to a song, or feeling a breeze on the skin, we coherently experience these stimuli as continuous, seamless percepts. However, there are rare perceptual phenomena that argue against continuous perception but, instead, suggest discrete processing of sensory input. Empirical evidence supporting such a discrete mechanism, however, remains scarce and comes entirely from the visual domain. Here, we demonstrate compelling evidence for discrete perceptual sampling in the somatosensory domain. Using magnetoencephalography (MEG) and a tactile temporal discrimination task in humans, we find that oscillatory alpha- and low beta-band (8-20 Hz) cycles in primary somatosensory cortex represent neurophysiological correlates of discrete perceptual cycles. Our results agree with several theoretical concepts of discrete perceptual sampling and empirical evidence of perceptual cycles in the visual domain. Critically, these results show that discrete perceptual cycles are not domain-specific, and thus restricted to the visual domain, but extend to the somatosensory domain.

  1. Mishaps, errors, and cognitive experiences: On the conceptualization of perceptual illusions

    Directory of Open Access Journals (Sweden)

    Daniele eZavagno

    2015-04-01

    Full Text Available Although a visual illusion is often viewed as an amusing trick, for the vision scientist it is a question that demands an answer, which leads to even more questioning. All researchers hold their own chain of questions, the links of which depend on the very theory they adhere to. Perceptual theories are devoted to answering questions concerning sensation and perception, but in doing so they shape concepts such as reality and representation, which necessarily affect the concept of illusion. Here we consider the macroscopic aspects of such concepts in vision sciences from three classic viewpoints – Ecological, Cognitive, Gestalt approaches – as we see this a starting point to understand in which terms illusions can become a tool in the hand of the neuroscientist. In fact, illusions can be effective tools in studying the brain in reference to perception and also to cognition in a much broader sense. A theoretical debate is, however, mandatory, in particular with regards to concepts such as veridicality and representation. Whether a perceptual outcome is considered as veridical or illusory (and, consequently, whether a class of phenomena should be classified as perceptual illusions or not depends on the meaning of such concepts.

  2. Heterogeneity in Perceptual Category Learning by High Functioning Children with Autism Spectrum Disorder

    Directory of Open Access Journals (Sweden)

    Eduardo eMercado

    2015-06-01

    Full Text Available Previous research suggests that high functioning children with Autism Spectrum Disorder (ASD sometimes have problems learning categories, but often appear to perform normally in categorization tasks. The deficits that individuals with ASD show when learning categories have been attributed to executive dysfunction, general deficits in implicit learning, atypical cognitive strategies, or abnormal perceptual biases and abilities. Several of these psychological explanations for category learning deficits have been associated with neural abnormalities such as cortical underconnectivity. The present study evaluated how well existing neurally-based theories account for atypical perceptual category learning shown by high functioning children with ASD across multiple category learning tasks involving novel, abstract shapes. Consistent with earlier results, children’s performances revealed two distinct patterns of learning and generalization associated with ASD: one was indistinguishable from performance in typically developing children; the other revealed dramatic impairments. These two patterns were evident regardless of training regimen or stimulus set. Surprisingly, some children with ASD showed both patterns. Simulations of perceptual category learning could account for the two observed patterns in terms of differences in neural plasticity. However, no current psychological or neural theory adequately explains why a child with ASD might show such large fluctuations in category learning ability across training conditions or stimulus sets.

  3. Heterogeneity in perceptual category learning by high functioning children with autism spectrum disorder.

    Science.gov (United States)

    Mercado, Eduardo; Church, Barbara A; Coutinho, Mariana V C; Dovgopoly, Alexander; Lopata, Christopher J; Toomey, Jennifer A; Thomeer, Marcus L

    2015-01-01

    Previous research suggests that high functioning (HF) children with autism spectrum disorder (ASD) sometimes have problems learning categories, but often appear to perform normally in categorization tasks. The deficits that individuals with ASD show when learning categories have been attributed to executive dysfunction, general deficits in implicit learning, atypical cognitive strategies, or abnormal perceptual biases and abilities. Several of these psychological explanations for category learning deficits have been associated with neural abnormalities such as cortical underconnectivity. The present study evaluated how well existing neurally based theories account for atypical perceptual category learning shown by HF children with ASD across multiple category learning tasks involving novel, abstract shapes. Consistent with earlier results, children's performances revealed two distinct patterns of learning and generalization associated with ASD: one was indistinguishable from performance in typically developing children; the other revealed dramatic impairments. These two patterns were evident regardless of training regimen or stimulus set. Surprisingly, some children with ASD showed both patterns. Simulations of perceptual category learning could account for the two observed patterns in terms of differences in neural plasticity. However, no current psychological or neural theory adequately explains why a child with ASD might show such large fluctuations in category learning ability across training conditions or stimulus sets.

  4. How mechanisms of perceptual decision-making affect the psychometric function.

    Science.gov (United States)

    Gold, Joshua I; Ding, Long

    2013-04-01

    Psychometric functions are often interpreted in the context of Signal Detection Theory, which emphasizes a distinction between sensory processing and non-sensory decision rules in the brain. This framework has helped to relate perceptual sensitivity to the "neurometric" sensitivity of sensory-driven neural activity. However, perceptual sensitivity, as interpreted via Signal Detection Theory, is based on not just how the brain represents relevant sensory information, but also how that information is read out to form the decision variable to which the decision rule is applied. Here we discuss recent advances in our understanding of this readout process and describe its effects on the psychometric function. In particular, we show that particular aspects of the readout process can have specific, identifiable effects on the threshold, slope, upper asymptote, time dependence, and choice dependence of psychometric functions. To illustrate these points, we emphasize studies of perceptual learning that have identified changes in the readout process that can lead to changes in these aspects of the psychometric function. We also discuss methods that have been used to distinguish contributions of the sensory representation versus its readout to psychophysical performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Illusory conjunctions and perceptual grouping in a visual search task in schizophrenia.

    Science.gov (United States)

    Carr, V J; Dewis, S A; Lewin, T J

    1998-07-27

    This report describes part of a series of experiments, conducted within the framework of feature integration theory, to determine whether patients with schizophrenia show deficits in preattentive processing. Thirty subjects with a DSM-III-R diagnosis of schizophrenia and 30 age-, gender-, and education-matched normal control subjects completed two computerized experimental tasks, a visual search task assessing the frequency of illusory conjunctions (i.e. false perceptions) under conditions of divided attention (Experiment 3) and a task which examined the effects of perceptual grouping on illusory conjunctions (Experiment 4). We also assessed current symptomatology and its relationship to task performance. Contrary to our hypotheses, schizophrenia subjects did not show higher rates of illusory conjunctions, and the influence of perceptual grouping on the frequency of illusory conjunctions was similar for schizophrenia and control subjects. Nonetheless, specific predictions from feature integration theory about the impact of different target types (Experiment 3) and perceptual groups (Experiment 4) on the likelihood of forming an illusory conjunction were strongly supported, thereby confirming the integrity of the experimental procedures. Overall, these studies revealed no firm evidence that schizophrenia is associated with a preattentive abnormality in visual search using stimuli that differ on the basis of physical characteristics.

  6. Shared mechanisms of perceptual learning and decision making.

    Science.gov (United States)

    Law, Chi-Tat; Gold, Joshua I

    2010-04-01

    Perceptual decisions require the brain to weigh noisy evidence from sensory neurons to form categorical judgments that guide behavior. Here we review behavioral and neurophysiological findings suggesting that at least some forms of perceptual learning do not appear to affect the response properties of neurons that represent the sensory evidence. Instead, improved perceptual performance results from changes in how the sensory evidence is selected and weighed to form the decision. We discuss the implications of this idea for possible sites and mechanisms of training-induced improvements in perceptual processing in the brain. Copyright © 2009 Cognitive Science Society, Inc.

  7. Summation versus suppression in metacontrast masking: On the potential pitfalls of using metacontrast masking to assess perceptual-motor dissociation.

    Science.gov (United States)

    Cardoso-Leite, Pedro; Waszak, Florian

    2014-07-01

    A briefly flashed target stimulus can become "invisible" when immediately followed by a mask-a phenomenon known as backward masking, which constitutes a major tool in the cognitive sciences. One form of backward masking is termed metacontrast masking. It is generally assumed that in metacontrast masking, the mask suppresses activity on which the conscious perception of the target relies. This assumption biases conclusions when masking is used as a tool-for example, to study the independence between perceptual detection and motor reaction. This is because other models can account for reduced perceptual performance without requiring suppression mechanisms. In this study, we used signal detection theory to test the suppression model against an alternative view of metacontrast masking, referred to as the summation model. This model claims that target- and mask-related activations fuse and that the difficulty in detecting the target results from the difficulty to discriminate this fused response from the response produced by the mask alone. Our data support this alternative view. This study is not a thorough investigation of metacontrast masking. Instead, we wanted to point out that when a different model is used to account for the reduced perceptual performance in metacontrast masking, there is no need to postulate a dissociation between perceptual and motor responses to account for the data. Metacontrast masking, as implemented in the Fehrer-Raab situation, therefore is not a valid method to assess perceptual-motor dissociations.

  8. Perceptual dimensions of style in paintings

    Directory of Open Access Journals (Sweden)

    Marković Slobodan

    2007-01-01

    Full Text Available The main purpose of this study is to specify the basic perceptual dimensions underlying the judgments of the physical features which define the style in paintings (e.g. salient form, colorful surface, oval contours etc.. The other aim of the study is to correlate these dimensions with the subjective (affective dimensions of the experience of paintings. In the preliminary study a set of 25 pairs of elementary perceptual descriptors were empirically specified, and a set of 25 bipolar scales were made (e.g. uncolored-multicolored. In the experiment 30 subjects judged 24 paintings (paintings were taken from the study of Radonjić and Marković, 2004 on 25 scales. Factor analysis revealed the four factors: form (scales: precise, neat, salient form etc., color (color contrast, lightness contrast, vivid colors, space (voluminosity, depth and oval contours and complexity (multicolored, ornate, detailed. Obtained factors reflected the nature of the phenomenological and neural segregation of form, color, depth processing, and partially of complexity processing (e.g. spatial frequency processing within both the form and color subsystem. The aim of the next step of analysis was to specify the correlations between two groups of judgments: (a mean judgments of 24 paintings on perceptual factors and (b mean judgments of the same set of 24 paintings on subjective (affective experience factors, i.e. regularity, attraction, arousal and relaxation (judgments taken from Radonjić and Marković, 2005. The following significant correlations were obtained: regularity-form, regularity-space, attraction-form and arousal-complexity (negative correlation. The reasons for the unexpected negative correlation between arousal and complexity should be specified in further studies.

  9. Visual-perceptual mismatch in robotic surgery.

    Science.gov (United States)

    Abiri, Ahmad; Tao, Anna; LaRocca, Meg; Guan, Xingmin; Askari, Syed J; Bisley, James W; Dutson, Erik P; Grundfest, Warren S

    2017-08-01

    The principal objective of the experiment was to analyze the effects of the clutch operation of robotic surgical systems on the performance of the operator. The relative coordinate system introduced by the clutch operation can introduce a visual-perceptual mismatch which can potentially have negative impact on a surgeon's performance. We also assess the impact of the introduction of additional tactile sensory information on reducing the impact of visual-perceptual mismatch on the performance of the operator. We asked 45 novice subjects to complete peg transfers using the da Vinci IS 1200 system with grasper-mounted, normal force sensors. The task involves picking up a peg with one of the robotic arms, passing it to the other arm, and then placing it on the opposite side of the view. Subjects were divided into three groups: aligned group (no mismatch), the misaligned group (10 cm z axis mismatch), and the haptics-misaligned group (haptic feedback and z axis mismatch). Each subject performed the task five times, during which the grip force, time of completion, and number of faults were recorded. Compared to the subjects that performed the tasks using a properly aligned controller/arm configuration, subjects with a single-axis misalignment showed significantly more peg drops (p = 0.011) and longer time to completion (p sensors showed no difference between the different groups. The visual-perceptual mismatch created by the misalignment of the robotic controls relative to the robotic arms has a negative impact on the operator of a robotic surgical system. Introduction of other sensory information and haptic feedback systems can help in potentially reducing this effect.

  10. Perceptual consequences of disrupted auditory nerve activity.

    Science.gov (United States)

    Zeng, Fan-Gang; Kong, Ying-Yee; Michalewski, Henry J; Starr, Arnold

    2005-06-01

    Perceptual consequences of disrupted auditory nerve activity were systematically studied in 21 subjects who had been clinically diagnosed with auditory neuropathy (AN), a recently defined disorder characterized by normal outer hair cell function but disrupted auditory nerve function. Neurological and electrophysical evidence suggests that disrupted auditory nerve activity is due to desynchronized or reduced neural activity or both. Psychophysical measures showed that the disrupted neural activity has minimal effects on intensity-related perception, such as loudness discrimination, pitch discrimination at high frequencies, and sound localization using interaural level differences. In contrast, the disrupted neural activity significantly impairs timing related perception, such as pitch discrimination at low frequencies, temporal integration, gap detection, temporal modulation detection, backward and forward masking, signal detection in noise, binaural beats, and sound localization using interaural time differences. These perceptual consequences are the opposite of what is typically observed in cochlear-impaired subjects who have impaired intensity perception but relatively normal temporal processing after taking their impaired intensity perception into account. These differences in perceptual consequences between auditory neuropathy and cochlear damage suggest the use of different neural codes in auditory perception: a suboptimal spike count code for intensity processing, a synchronized spike code for temporal processing, and a duplex code for frequency processing. We also proposed two underlying physiological models based on desynchronized and reduced discharge in the auditory nerve to successfully account for the observed neurological and behavioral data. These methods and measures cannot differentiate between these two AN models, but future studies using electric stimulation of the auditory nerve via a cochlear implant might. These results not only show the unique

  11. Nicotine facilitates memory consolidation in perceptual learning.

    Science.gov (United States)

    Beer, Anton L; Vartak, Devavrat; Greenlee, Mark W

    2013-01-01

    Perceptual learning is a special type of non-declarative learning that involves experience-dependent plasticity in sensory cortices. The cholinergic system is known to modulate declarative learning. In particular, reduced levels or efficacy of the neurotransmitter acetylcholine were found to facilitate declarative memory consolidation. However, little is known about the role of the cholinergic system in memory consolidation of non-declarative learning. Here we compared two groups of non-smoking men who learned a visual texture discrimination task (TDT). One group received chewing tobacco containing nicotine for 1 h directly following the TDT training. The other group received a similar tasting control substance without nicotine. Electroencephalographic recordings during substance consumption showed reduced alpha activity and P300 latencies in the nicotine group compared to the control group. When re-tested on the TDT the following day, both groups responded more accurately and more rapidly than during training. These improvements were specific to the retinal location and orientation of the texture elements of the TDT suggesting that learning involved early visual cortex. A group comparison showed that learning effects were more pronounced in the nicotine group than in the control group. These findings suggest that oral consumption of nicotine enhances the efficacy of nicotinic acetylcholine receptors. Our findings further suggest that enhanced efficacy of the cholinergic system facilitates memory consolidation in perceptual learning (and possibly other types of non-declarative learning). In that regard acetylcholine seems to affect consolidation processes in perceptual learning in a different manner than in declarative learning. Alternatively, our findings might reflect dose-dependent cholinergic modulation of memory consolidation. This article is part of a Special Issue entitled 'Cognitive Enhancers'. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Normative perceptual estimates for 91 healthy subjects age 60-75

    DEFF Research Database (Denmark)

    Wilms, Inge Linda; Nielsen, Simon

    2014-01-01

    Visual perception serves as the basis for much of the higher level cognitive processing as well as human activity in general. Here we present normative estimates for the following components of visual perception: the visual perceptual threshold, the visual short-term memory capacity and the visual...... perceptual encoding/decoding speed (processing speed) of visual short-term memory based on an assessment of 91 healthy subjects aged 60-75. The estimates are presented at total sample level as well as at gender level. The estimates were modelled from input from a whole-report assessment based on A Theory...... speed of Visual Short-term Memory (VTSM) but not the capacity of VSTM nor the visual threshold. The estimates will be useful for future studies into the effects of various types of intervention and training on cognition in general and visual attention in particular....

  13. In the Eye of the Betrothed: Perceptual Downgrading of Attractive Alternative Romantic Partners.

    Science.gov (United States)

    Cole, Shana; Trope, Yaacov; Balcetis, Emily

    2016-07-01

    People in monogamous relationships can experience a conflict when they interact with an attractive individual. They may have a desire to romantically pursue the new person, while wanting to be faithful to their partner. How do people manage the threat that attractive alternatives present to their relationship goals? We suggest that one way people defend their relationships against attractive individuals is by perceiving the individual as less attractive. In two studies, using a novel visual matching paradigm, we found support for a perceptual downgrading effect. People in relationships perceived threatening attractive individuals as less attractive than did single participants. The effect was exacerbated among participants who were highly satisfied with their current relationships. The studies provide evidence for a perceptual bias that emerges to protect long-term goals. We discuss the findings within the context of a broader theory of motivated perception in the service of self-control. © 2016 by the Society for Personality and Social Psychology, Inc.

  14. Eliciting Perceptual Ground Truth for Image Segmentation

    OpenAIRE

    Hodge, Victoria Jane; Eakins, John; Austin, Jim

    2006-01-01

    In this paper, we investigate human visual perception and establish a body of ground truth data elicited from human visual studies. We aim to build on the formative work of Ren, Eakins and Briggs who produced an initial ground truth database. Human subjects were asked to draw and rank their perceptions of the parts of a series of figurative images. These rankings were then used to score the perceptions, identify the preferred human breakdowns and thus allow us to induce perceptual rules for h...

  15. False Memories Lack Perceptual Detail: Evidence from Implicit Word-Stem Completion and Perceptual Identification Tests

    Science.gov (United States)

    Hicks, J.L.; Starns, J.J.

    2005-01-01

    We used implicit measures of memory to ascertain whether false memories for critical nonpresented items in the DRM paradigm (Deese, 1959; Roediger & McDermott, 1995) contain structural and perceptual detail. In Experiment 1, we manipulated presentation modality in a visual word-stem-completion task. Critical item priming was significant and…

  16. Perceptual Fluency, Auditory Generation, and Metamemory: Analyzing the Perceptual Fluency Hypothesis in the Auditory Modality

    Science.gov (United States)

    Besken, Miri; Mulligan, Neil W.

    2014-01-01

    Judgments of learning (JOLs) are sometimes influenced by factors that do not impact actual memory performance. One recent proposal is that perceptual fluency during encoding affects metamemory and is a basis of metacognitive illusions. In the present experiments, participants identified aurally presented words that contained inter-spliced silences…

  17. Working memory load improves early stages of independent visual processing.

    Science.gov (United States)

    Cocchi, Luca; Toepel, Ulrike; De Lucia, Marzia; Martuzzi, Roberto; Wood, Stephen J; Carter, Olivia; Murray, Micah M

    2011-01-01

    Increasing evidence suggests that working memory and perceptual processes are dynamically interrelated due to modulating activity in overlapping brain networks. However, the direct influence of working memory on the spatio-temporal brain dynamics of behaviorally relevant intervening information remains unclear. To investigate this issue, subjects performed a visual proximity grid perception task under three different visual-spatial working memory (VSWM) load conditions. VSWM load was manipulated by asking subjects to memorize the spatial locations of 6 or 3 disks. The grid was always presented between the encoding and recognition of the disk pattern. As a baseline condition, grid stimuli were presented without a VSWM context. VSWM load altered both perceptual performance and neural networks active during intervening grid encoding. Participants performed faster and more accurately on a challenging perceptual task under high VSWM load as compared to the low load and the baseline condition. Visual evoked potential (VEP) analyses identified changes in the configuration of the underlying sources in one particular period occurring 160-190 ms post-stimulus onset. Source analyses further showed an occipito-parietal down-regulation concurrent to the increased involvement of temporal and frontal resources in the high VSWM context. Together, these data suggest that cognitive control mechanisms supporting working memory may selectively enhance concurrent visual processing related to an independent goal. More broadly, our findings are in line with theoretical models implicating the engagement of frontal regions in synchronizing and optimizing mnemonic and perceptual resources towards multiple goals. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Perceptual organization at attended and unattended locations

    Institute of Scientific and Technical Information of China (English)

    HAN Shihui; Glyn W. Humphreys

    2005-01-01

    This study examined the effects of attention on forming perceptual units by proximity grouping and by uniform connectedness (UC). In Experiment 1 a row of three global letters defined by either proximity or UC was presented at the center of the visual field. Participants were asked to identify the letter in the middle of stimulus arrays while ignoring the flankers. The stimulus onset asynchrony (SOA) between stimulus arrays and masks varied between 180 and 500 ms. We found that responses to targets defined by proximity grouping were slower than to those defined by UC at median SOAs but there were no differences at short or long SOAs. Incongruent flankers slowed responses to targets and this flanker compatibility effect was larger for UC than for proximity-defined flankers. Experiment 2 examined the effects of spatial precueing on discrimination responses to proximity- and UC-defined targets. The advantage for targets defined by UC over targets defined by proximity grouping was greater at uncued relative to cued locations. The results suggest that the advantage for UC over proximity grouping in forming perceptual units is contingent on the stimuli not being fully attended, and that paying attention to the stimuli differentially benefits proximity grouping.

  19. Implicit Recognition Based on Lateralized Perceptual Fluency

    Directory of Open Access Journals (Sweden)

    Iliana M. Vargas

    2012-02-01

    Full Text Available In some circumstances, accurate recognition of repeated images in an explicit memory test is driven by implicit memory. We propose that this “implicit recognition” results from perceptual fluency that influences responding without awareness of memory retrieval. Here we examined whether recognition would vary if images appeared in the same or different visual hemifield during learning and testing. Kaleidoscope images were briefly presented left or right of fixation during divided-attention encoding. Presentation in the same visual hemifield at test produced higher recognition accuracy than presentation in the opposite visual hemifield, but only for guess responses. These correct guesses likely reflect a contribution from implicit recognition, given that when the stimulated visual hemifield was the same at study and test, recognition accuracy was higher for guess responses than for responses with any level of confidence. The dramatic difference in guessing accuracy as a function of lateralized perceptual overlap between study and test suggests that implicit recognition arises from memory storage in visual cortical networks that mediate repetition-induced fluency increments.

  20. Perceptual learning during action video game playing.

    Science.gov (United States)

    Green, C Shawn; Li, Renjie; Bavelier, Daphne

    2010-04-01

    Action video games have been shown to enhance behavioral performance on a wide variety of perceptual tasks, from those that require effective allocation of attentional resources across the visual scene, to those that demand the successful identification of fleetingly presented stimuli. Importantly, these effects have not only been shown in expert action video game players, but a causative link has been established between action video game play and enhanced processing through training studies. Although an account based solely on attention fails to capture the variety of enhancements observed after action game playing, a number of models of perceptual learning are consistent with the observed results, with behavioral modeling favoring the hypothesis that avid video game players are better able to form templates for, or extract the relevant statistics of, the task at hand. This may suggest that the neural site of learning is in areas where information is integrated and actions are selected; yet changes in low-level sensory areas cannot be ruled out. Copyright © 2009 Cognitive Science Society, Inc.

  1. Implicit recognition based on lateralized perceptual fluency.

    Science.gov (United States)

    Vargas, Iliana M; Voss, Joel L; Paller, Ken A

    2012-02-06

    In some circumstances, accurate recognition of repeated images in an explicit memory test is driven by implicit memory. We propose that this "implicit recognition" results from perceptual fluency that influences responding without awareness of memory retrieval. Here we examined whether recognition would vary if images appeared in the same or different visual hemifield during learning and testing. Kaleidoscope images were briefly presented left or right of fixation during divided-attention encoding. Presentation in the same visual hemifield at test produced higher recognition accuracy than presentation in the opposite visual hemifield, but only for guess responses. These correct guesses likely reflect a contribution from implicit recognition, given that when the stimulated visual hemifield was the same at study and test, recognition accuracy was higher for guess responses than for responses with any level of confidence. The dramatic difference in guessing accuracy as a function of lateralized perceptual overlap between study and test suggests that implicit recognition arises from memory storage in visual cortical networks that mediate repetition-induced fluency increments.

  2. Revisiting the empirical case against perceptual modularity

    Science.gov (United States)

    Masrour, Farid; Nirshberg, Gregory; Schon, Michael; Leardi, Jason; Barrett, Emily

    2015-01-01

    Some theorists hold that the human perceptual system has a component that receives input only from units lower in the perceptual hierarchy. This thesis, that we shall here refer to as the encapsulation thesis, has been at the center of a continuing debate for the past few decades. Those who deny the encapsulation thesis often rely on the large body of psychological findings that allegedly suggest that perception is influenced by factors such as the beliefs, desires, goals, and the expectations of the perceiver. Proponents of the encapsulation thesis, however, often argue that, when correctly interpreted, these psychological findings are compatible with the thesis. In our view, the debate over the significance and the correct interpretation of these psychological findings has reached an impasse. We hold that this impasse is due to the methodological limitations over psychophysical experiments, and it is very unlikely that such experiments, on their own, could yield results that would settle the debate. After defending this claim, we argue that integrating data from cognitive neuroscience resolves the debate in favor of those who deny the encapsulation thesis. PMID:26583001

  3. Motivation and intelligence drive auditory perceptual learning.

    Science.gov (United States)

    Amitay, Sygal; Halliday, Lorna; Taylor, Jenny; Sohoglu, Ediz; Moore, David R

    2010-03-23

    Although feedback on performance is generally thought to promote perceptual learning, the role and necessity of feedback remain unclear. We investigated the effect of providing varying amounts of positive feedback while listeners attempted to discriminate between three identical tones on learning frequency discrimination. Using this novel procedure, the feedback was meaningless and random in relation to the listeners' responses, but the amount of feedback provided (or lack thereof) affected learning. We found that a group of listeners who received positive feedback on 10% of the trials improved their performance on the task (learned), while other groups provided either with excess (90%) or with no feedback did not learn. Superimposed on these group data, however, individual listeners showed other systematic changes of performance. In particular, those with lower non-verbal IQ who trained in the no feedback condition performed more poorly after training. This pattern of results cannot be accounted for by learning models that ascribe an external teacher role to feedback. We suggest, instead, that feedback is used to monitor performance on the task in relation to its perceived difficulty, and that listeners who learn without the benefit of feedback are adept at self-monitoring of performance, a trait that also supports better performance on non-verbal IQ tests. These results show that 'perceptual' learning is strongly influenced by top-down processes of motivation and intelligence.

  4. Perceptual categories enable pattern generalization in songbirds.

    Science.gov (United States)

    Comins, Jordan A; Gentner, Timothy Q

    2013-08-01

    Since Chomsky's pioneering work on syntactic structures, comparative psychologists interested in the study of language evolution have targeted pattern complexity, using formal mathematical grammars, as the key to organizing language-relevant cognitive processes across species. This focus on formal syntactic complexity, however, often disregards the close interaction in real-world signals between the structure of a pattern and its constituent elements. Whether such features of natural auditory signals shape pattern generalization is unknown. In the present paper, we train birds to recognize differently patterned strings of natural signals (song motifs). Instead of focusing on the complexity of the overtly reinforced patterns, we ask how the perceptual groupings of pattern elements influence the generalization pattern knowledge. We find that learning and perception of training patterns is agnostic to the perceptual features of underlying elements. Surprisingly, however, these same features constrain the generalization of pattern knowledge, and thus its broader use. Our results demonstrate that the restricted focus of comparative language research on formal models of syntactic complexity is, at best, insufficient to understand pattern use. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Medical students' cognitive load in volumetric image interpretation : Insights from human-computer interaction and eye movements

    NARCIS (Netherlands)

    Stuijfzand, Bobby G.; Van Der Schaaf, Marieke F.; Kirschner, Femke C.; Ravesloot, Cécile J.; Van Der Gijp, Anouk; Vincken, Koen L.

    2016-01-01

    Medical image interpretation is moving from using 2D- to volumetric images, thereby changing the cognitive and perceptual processes involved. This is expected to affect medical students' experienced cognitive load, while learning image interpretation skills. With two studies this explorative

  6. Posterior Probability Matching and Human Perceptual Decision Making.

    Directory of Open Access Journals (Sweden)

    Richard F Murray

    2015-06-01

    Full Text Available Probability matching is a classic theory of decision making that was first developed in models of cognition. Posterior probability matching, a variant in which observers match their response probabilities to the posterior probability of each response being correct, is being used increasingly often in models of perception. However, little is known about whether posterior probability matching is consistent with the vast literature on vision and hearing that has developed within signal detection theory. Here we test posterior probability matching models using two tools from detection theory. First, we examine the models' performance in a two-pass experiment, where each block of trials is presented twice, and we measure the proportion of times that the model gives the same response twice to repeated stimuli. We show that at low performance levels, posterior probability matching models give highly inconsistent responses across repeated presentations of identical trials. We find that practised human observers are more consistent across repeated trials than these models predict, and we find some evidence that less practised observers more consistent as well. Second, we compare the performance of posterior probability matching models on a discrimination task to the performance of a theoretical ideal observer that achieves the best possible performance. We find that posterior probability matching is very inefficient at low-to-moderate performance levels, and that human observers can be more efficient than is ever possible according to posterior probability matching models. These findings support classic signal detection models, and rule out a broad class of posterior probability matching models for expert performance on perceptual tasks that range in complexity from contrast discrimination to symmetry detection. However, our findings leave open the possibility that inexperienced observers may show posterior probability matching behaviour, and our methods

  7. Perceptual Specificity Effects in Rereading: Evidence from Eye Movements

    Science.gov (United States)

    Sheridan, Heather; Reingold, Eyal M.

    2012-01-01

    The present experiments examined perceptual specificity effects using a rereading paradigm. Eye movements were monitored while participants read the same target word twice, in two different low-constraint sentence frames. The congruency of perceptual processing was manipulated by either presenting the target word in the same distortion typography…

  8. Perceptual Organization of Visual Structure Requires a Flexible Learning Mechanism

    Science.gov (United States)

    Aslin, Richard N.

    2011-01-01

    Bhatt and Quinn (2011) provide a compelling and comprehensive review of empirical evidence that supports the operation of principles of perceptual organization in young infants. They also have provided a comprehensive list of experiences that could serve to trigger the learning of at least some of these principles of perceptual organization, and…

  9. Perceptual biases in relation to paranormal and conspiracy beliefs

    NARCIS (Netherlands)

    van Elk, M.

    2015-01-01

    Previous studies have shown that one’s prior beliefs have a strong effect on perceptual decision-making and attentional processing. The present study extends these findings by investigating how individual differences in paranormal and conspiracy beliefs are related to perceptual and attentional

  10. A Neural Signature Encoding Decisions under Perceptual Ambiguity.

    Science.gov (United States)

    Sun, Sai; Yu, Rongjun; Wang, Shuo

    2017-01-01

    People often make perceptual decisions with ambiguous information, but it remains unclear whether the brain has a common neural substrate that encodes various forms of perceptual ambiguity. Here, we used three types of perceptually ambiguous stimuli as well as task instructions to examine the neural basis for both stimulus-driven and task-driven perceptual ambiguity. We identified a neural signature, the late positive potential (LPP), that encoded a general form of stimulus-driven perceptual ambiguity. In addition to stimulus-driven ambiguity, the LPP was also modulated by ambiguity in task instructions. To further specify the functional role of the LPP and elucidate the relationship between stimulus ambiguity, behavioral response, and the LPP, we employed regression models and found that the LPP was specifically associated with response latency and confidence rating, suggesting that the LPP encoded decisions under perceptual ambiguity. Finally, direct behavioral ratings of stimulus and task ambiguity confirmed our neurophysiological findings, which could not be attributed to differences in eye movements either. Together, our findings argue for a common neural signature that encodes decisions under perceptual ambiguity but is subject to the modulation of task ambiguity. Our results represent an essential first step toward a complete neural understanding of human perceptual decision making.

  11. Ambiguity Tolerance and Perceptual Learning Styles of Chinese EFL Learners

    Science.gov (United States)

    Li, Haishan; He, Qingshun

    2016-01-01

    Ambiguity tolerance and perceptual learning styles are the two influential elements showing individual differences in EFL learning. This research is intended to explore the relationship between Chinese EFL learners' ambiguity tolerance and their preferred perceptual learning styles. The findings include (1) the learners are sensitive to English…

  12. A Novel Perceptual Hash Algorithm for Multispectral Image Authentication

    Directory of Open Access Journals (Sweden)

    Kaimeng Ding

    2018-01-01

    Full Text Available The perceptual hash algorithm is a technique to authenticate the integrity of images. While a few scholars have worked on mono-spectral image perceptual hashing, there is limited research on multispectral image perceptual hashing. In this paper, we propose a perceptual hash algorithm for the content authentication of a multispectral remote sensing image based on the synthetic characteristics of each band: firstly, the multispectral remote sensing image is preprocessed with band clustering and grid partition; secondly, the edge feature of the band subsets is extracted by band fusion-based edge feature extraction; thirdly, the perceptual feature of the same region of the band subsets is compressed and normalized to generate the perceptual hash value. The authentication procedure is achieved via the normalized Hamming distance between the perceptual hash value of the recomputed perceptual hash value and the original hash value. The experiments indicated that our proposed algorithm is robust compared to content-preserved operations and it efficiently authenticates the integrity of multispectral remote sensing images.

  13. Neurological evidence linguistic processes precede perceptual simulation in conceptual processing.

    Science.gov (United States)

    Louwerse, Max; Hutchinson, Sterling

    2012-01-01

    There is increasing evidence from response time experiments that language statistics and perceptual simulations both play a role in conceptual processing. In an EEG experiment we compared neural activity in cortical regions commonly associated with linguistic processing and visual perceptual processing to determine to what extent symbolic and embodied accounts of cognition applied. Participants were asked to determine the semantic relationship of word pairs (e.g., sky - ground) or to determine their iconic relationship (i.e., if the presentation of the pair matched their expected physical relationship). A linguistic bias was found toward the semantic judgment task and a perceptual bias was found toward the iconicity judgment task. More importantly, conceptual processing involved activation in brain regions associated with both linguistic and perceptual processes. When comparing the relative activation of linguistic cortical regions with perceptual cortical regions, the effect sizes for linguistic cortical regions were larger than those for the perceptual cortical regions early in a trial with the reverse being true later in a trial. These results map upon findings from other experimental literature and provide further evidence that processing of concept words relies both on language statistics and on perceptual simulations, whereby linguistic processes precede perceptual simulation processes.

  14. Selective Attention to Perceptual Dimensions and Switching between Dimensions

    Science.gov (United States)

    Meiran, Nachshon; Dimov, Eduard; Ganel, Tzvi

    2013-01-01

    In the present experiments, the question being addressed was whether switching attention between perceptual dimensions and selective attention to dimensions are processes that compete over a common resource? Attention to perceptual dimensions is usually studied by requiring participants to ignore a never-relevant dimension. Selection failure…

  15. Attention without awareness: Attentional modulation of perceptual grouping without awareness.

    Science.gov (United States)

    Lo, Shih-Yu

    2018-04-01

    Perceptual grouping is the process through which the perceptual system combines local stimuli into a more global perceptual unit. Previous studies have shown attention to be a modulatory factor for perceptual grouping. However, these studies mainly used explicit measurements, and, thus, whether attention can modulate perceptual grouping without awareness is still relatively unexplored. To clarify the relationship between attention and perceptual grouping, the present study aims to explore how attention interacts with perceptual grouping without awareness. The task was to judge the relative lengths of two centrally presented horizontal bars while a railway-shaped pattern defined by color similarity was presented in the background. Although the observers were unaware of the railway-shaped pattern, their line-length judgment was biased by that pattern, which induced a Ponzo illusion, indicating grouping without awareness. More importantly, an attentional modulatory effect without awareness was manifested as evident by the observer's performance being more often biased when the railway-shaped pattern was formed by an attended color than when it was formed by an unattended one. Also, the attentional modulation effect was shown to be dynamic, being more pronounced with a short presentation time than a longer one. The results of the present study not only clarify the relationship between attention and perceptual grouping but also further contribute to our understanding of attention and awareness by corroborating the dissociation between attention and awareness.

  16. Perceptual maps: the good, the bad and the ugly

    NARCIS (Netherlands)

    J.C. Gower (John); P.J.F. Groenen (Patrick); M. van de Velden (Michel); K. Vines (Karen)

    2010-01-01

    textabstractPerceptual maps are often used in marketing to visually study relations between two or more attributes. However, in many perceptual maps published in the recent literature it remains unclear what is being shown and how the relations between the points in the map can be interpreted or

  17. Mode transition and change in variable use in perceptual learning

    NARCIS (Netherlands)

    Hajnal, A; Grocki, M; Jacobs, DM; Zaal, FTJM; Michaels, CF

    2006-01-01

    Runeson, Justin, and Olsson (2000) proposed (a) that perceptual learning entails a transition from an inferential to a direct-perceptual mode of apprehension, and (b) that relative confidence-the difference between estimated and actual performance-indicates whether apprehension is inferential or

  18. Mode transition and change in variable use in perceptual learning

    NARCIS (Netherlands)

    Hajnal, A.; Grocki, M.; Jacobs, D.M.; Zaal, F.T.J.M.; Michaels, C.F.

    2006-01-01

    Runeson, Juslin, and Olsson (2000) proposed (a) that perceptual learning entails a transition from an inferential to a direct-perceptual mode of apprehension, and (b) that relative confidence - the difference between estimated and actual performance - indicates whether apprehension is inferential or

  19. Perceptual Mapping: A Methodology in the Assessment of Environmental Perceptions.

    Science.gov (United States)

    Sergent, Marie T.; Sedlacek, William E.

    1989-01-01

    Describes perceptual mapping, a newly developed method for assessing perceptions of campus environments. Describes evaluation of a student union by students using this method. Discusses the advantages and disadvantages of this perceptual mapping method for assessing college environments. (Author/ABL)

  20. Gaze-contingent training enhances perceptual skill acquisition

    NARCIS (Netherlands)

    Mann, D.L.; Ryu, D.; Abernethy, B.A.; Poolton, J.M.

    2016-01-01

    The purpose of this study was to determine whether decision-making skill in perceptual-cognitive tasks could be enhanced using a training technique that impaired selective areas of the visual field. Recreational basketball players performed perceptual training over 3 days while viewing with a

  1. Perceptual Learning: 12-Month-Olds' Discrimination of Monkey Faces

    Science.gov (United States)

    Fair, Joseph; Flom, Ross; Jones, Jacob; Martin, Justin

    2012-01-01

    Six-month-olds reliably discriminate different monkey and human faces whereas 9-month-olds only discriminate different human faces. It is often falsely assumed that perceptual narrowing reflects a permanent change in perceptual abilities. In 3 experiments, ninety-six 12-month-olds' discrimination of unfamiliar monkey faces was examined. Following…

  2. Bayesian Face Recognition and Perceptual Narrowing in Face-Space

    Science.gov (United States)

    Balas, Benjamin

    2012-01-01

    During the first year of life, infants' face recognition abilities are subject to "perceptual narrowing", the end result of which is that observers lose the ability to distinguish previously discriminable faces (e.g. other-race faces) from one another. Perceptual narrowing has been reported for faces of different species and different races, in…

  3. Effect of body mass and midsole hardness on kinetic and perceptual variables during basketball landing manoeuvres.

    Science.gov (United States)

    Nin, Darren Z; Lam, Wing K; Kong, Pui W

    2016-01-01

    This study investigated the effects of body mass and shoe midsole hardness on kinetic and perceptual variables during the performance of three basketball movements: (1) the first and landing steps of layup, (2) shot-blocking landing and (3) drop landing. Thirty male basketball players, assigned into "heavy" (n = 15, mass 82.7 ± 4.3 kg) or "light" (n = 15, mass 63.1 ± 2.8 kg) groups, performed five trials of each movement in three identical shoes of varying midsole hardness (soft, medium, hard). Vertical ground reaction force (VGRF) during landing was sampled using multiple wooden-top force plates. Perceptual responses on five variables (forefoot cushioning, rearfoot cushioning, forefoot stability, rearfoot stability and overall comfort) were rated after each movement condition using a 150-mm Visual Analogue Scale (VAS). A mixed factorial analysis of variance (ANOVA) (Body Mass × Shoe) was applied to all kinetic and perceptual variables. During the first step of the layup, the loading rate associated with rearfoot contact was 40.7% higher in the "heavy" than "light" groups (P = .014) and 12.4% higher in hard compared with soft shoes (P = .011). Forefoot peak VGRF in a soft shoe was higher (P = .011) than in a hard shoe during shot-block landing. Both "heavy" and "light" groups preferred softer to harder shoes. Overall, body mass had little effect on kinetic or perceptual variables.

  4. Perceptual grouping over time within and across auditory and tactile modalities.

    Directory of Open Access Journals (Sweden)

    I-Fan Lin

    Full Text Available In auditory scene analysis, population separation and temporal coherence have been proposed to explain how auditory features are grouped together and streamed over time. The present study investigated whether these two theories can be applied to tactile streaming and whether temporal coherence theory can be applied to crossmodal streaming. The results show that synchrony detection between two tones/taps at different frequencies/locations became difficult when one of the tones/taps was embedded in a perceptual stream. While the taps applied to the same location were streamed over time, the taps applied to different locations were not. This observation suggests that tactile stream formation can be explained by population-separation theory. On the other hand, temporally coherent auditory stimuli at different frequencies were streamed over time, but temporally coherent tactile stimuli applied to different locations were not. When there was within-modality streaming, temporally coherent auditory stimuli and tactile stimuli were not streamed over time, either. This observation suggests the limitation of temporal coherence theory when it is applied to perceptual grouping over time.

  5. Plastic limit loads for cylindrical shell intersections under combined loading

    International Nuclear Information System (INIS)

    Skopinsky, V.N.; Berkov, N.A.; Vogov, R.A.

    2015-01-01

    In this research, applied methods of nonlinear analysis and results of determining the plastic limit loads for shell intersection configurations under combined internal pressure, in-plane moment and out-plane moment loadings are presented. The numerical analysis of shell intersections is performed using the finite element method, geometrically nonlinear shell theory in quadratic approximation and plasticity theory. For determining the load parameter of proportional combined loading, the developed maximum criterion of rate of change of relative plastic work is employed. The graphical results for model of cylindrical shell intersection under different two-parameter combined loadings (as generalized plastic limit load curves) and three-parameter combined loading (as generalized plastic limit load surface) are presented on the assumption that the internal pressure, in-plane moment and out-plane moment loads were applied in a proportional manner. - Highlights: • This paper presents nonlinear two-dimensional FE analysis for shell intersections. • Determining the plastic limit loads under combined loading is considered. • Developed maximum criterion of rate of change of relative plastic work is employed. • Plastic deformation mechanism in shell intersections is discussed. • Results for generalized plastic limit load curves of branch intersection are presented

  6. The effects of attention on perceptual implicit memory.

    Science.gov (United States)

    Rajaram, S; Srinivas, K; Travers, S

    2001-10-01

    Reports on the effects of dividing attention at study on subsequent perceptual priming suggest that perceptual priming is generally unaffected by attentional manipulations as long as word identity is processed. We tested this hypothesis in three experiments by using the implicit word fragment completion and word stem completion tasks. Division of attention was instantiated with the Stroop task in order to ensure the processing of word identity even when the participant's attention was directed to a stimulus attribute other than the word itself. Under these conditions, we found that even though perceptual priming was significant, it was significantly reduced in magnitude. A stem cued recall test in Experiment 2 confirmed a more deleterious effect of divided attention on explicit memory. Taken together, our findings delineate the relative contributions of perceptual analysis and attentional processes in mediating perceptual priming on two ubiquitously used tasks of word fragment completion and word stem completion.

  7. Natural texture retrieval based on perceptual similarity measurement

    Science.gov (United States)

    Gao, Ying; Dong, Junyu; Lou, Jianwen; Qi, Lin; Liu, Jun

    2018-04-01

    A typical texture retrieval system performs feature comparison and might not be able to make human-like judgments of image similarity. Meanwhile, it is commonly known that perceptual texture similarity is difficult to be described by traditional image features. In this paper, we propose a new texture retrieval scheme based on texture perceptual similarity. The key of the proposed scheme is that prediction of perceptual similarity is performed by learning a non-linear mapping from image features space to perceptual texture space by using Random Forest. We test the method on natural texture dataset and apply it on a new wallpapers dataset. Experimental results demonstrate that the proposed texture retrieval scheme with perceptual similarity improves the retrieval performance over traditional image features.

  8. Invitational Education: Theory, Research and Practice

    Science.gov (United States)

    Haigh, Martin

    2011-01-01

    Invitational Theory argues that learning is enhanced when learners are positively encouraged or "invited" into the educational experience. Arising from perceptual and self-concept theory, Invitational Pedagogy is constructed on four principles: respect for people, trust, optimism and intentionality, and upon five pillars: people, places, policies,…

  9. Combining principles of Cognitive Load Theory and diagnostic error analysis for designing job aids : Effects on motivation and diagnostic performance in a process control task

    NARCIS (Netherlands)

    Kluge, Annette; Grauel, Britta; Burkolter, Dina

    Two studies are presented in which the design of a procedural aid and the impact of an additional decision aid for process control were assessed. In Study 1, a procedural aid was developed that avoids imposing unnecessary extraneous cognitive load on novices when controlling a complex technical

  10. On Digital Film Theory: Liquid Cinema and Liquid Film Theory

    OpenAIRE

    Hakan Erkılıç

    2017-01-01

    Referring to Bauman’s (2005) concept of “liquid modernity”, this paper aims to discuss the new film theory that has emerged from the digitalization of cinema. The concepts of perceptual reality and elastic reality constitute the two most important parts of the theory. Bauman argues that contemporary modern societies are “liquid” because of their dynamic character. Although contemporary societies are in constant movement, he indicates that they lack certainty and borders, and flexibility and u...

  11. Load Balancing in Hypergraphs

    Science.gov (United States)

    Delgosha, Payam; Anantharam, Venkat

    2018-03-01

    Consider a simple locally finite hypergraph on a countable vertex set, where each edge represents one unit of load which should be distributed among the vertices defining the edge. An allocation of load is called balanced if load cannot be moved from a vertex to another that is carrying less load. We analyze the properties of balanced allocations of load. We extend the concept of balancedness from finite hypergraphs to their local weak limits in the sense of Benjamini and Schramm (Electron J Probab 6(23):13, 2001) and Aldous and Steele (in: Probability on discrete structures. Springer, Berlin, pp 1-72, 2004). To do this, we define a notion of unimodularity for hypergraphs which could be considered an extension of unimodularity in graphs. We give a variational formula for the balanced load distribution and, in particular, we characterize it in the special case of unimodular hypergraph Galton-Watson processes. Moreover, we prove the convergence of the maximum load under some conditions. Our work is an extension to hypergraphs of Anantharam and Salez (Ann Appl Probab 26(1):305-327, 2016), which considered load balancing in graphs, and is aimed at more comprehensively resolving conjectures of Hajek (IEEE Trans Inf Theory 36(6):1398-1414, 1990).

  12. The Role of Feedback Contingency in Perceptual Category Learning

    Science.gov (United States)

    Ashby, F. Gregory; Vucovich, Lauren E.

    2016-01-01

    Feedback is highly contingent on behavior if it eventually becomes easy to predict, and weakly contingent on behavior if it remains difficult or impossible to predict even after learning is complete. Many studies have demonstrated that humans and nonhuman animals are highly sensitive to feedback contingency, but no known studies have examined how feedback contingency affects category learning, and current theories assign little or no importance to this variable. Two experiments examined the effects of contingency degradation on rule-based and information-integration category learning. In rule-based tasks, optimal accuracy is possible with a simple explicit rule, whereas optimal accuracy in information-integration tasks requires integrating information from two or more incommensurable perceptual dimensions. In both experiments, participants each learned rule-based or information-integration categories under either high or low levels of feedback contingency. The exact same stimuli were used in all four conditions and optimal accuracy was identical in every condition. Learning was good in both high-contingency conditions, but most participants showed little or no evidence of learning in either low-contingency condition. Possible causes of these effects are discussed, as well as their theoretical implications. PMID:27149393

  13. Perceptual processing of a complex musical context

    DEFF Research Database (Denmark)

    Quiroga Martinez, David Ricardo; Hansen, Niels Christian; Højlund, Andreas

    play a fundamental role in music perception. The mismatch negativity (MMN) is a brain response that offers a unique insight into these processes. The MMN is elicited by deviants in a series of repetitive sounds and reflects the perception of change in physical and abstract sound regularities. Therefore......, it is regarded as a prediction error signal and a neural correlate of the updating of predictive perceptual models. In music, the MMN has been particularly valuable for the assessment of musical expectations, learning and expertise. However, the MMN paradigm has an important limitation: its ecological validity....... To this aim we will develop a new paradigm using more real-sounding stimuli. Our stimuli will be two-part music excerpts made by adding a melody to a previous design based on the Alberti bass (Vuust et al., 2011). Our second goal is to determine how the complexity of this context affects the predictive...

  14. Perceptual effects in auralization of virtual rooms

    Science.gov (United States)

    Kleiner, Mendel; Larsson, Pontus; Vastfjall, Daniel; Torres, Rendell R.

    2002-05-01

    By using various types of binaural simulation (or ``auralization'') of physical environments, it is now possible to study basic perceptual issues relevant to room acoustics, as well to simulate the acoustic conditions found in concert halls and other auditoria. Binaural simulation of physical spaces in general is also important to virtual reality systems. This presentation will begin with an overview of the issues encountered in the auralization of room and other environments. We will then discuss the influence of various approximations in room modeling, in particular, edge- and surface scattering, on the perceived room response. Finally, we will discuss cross-modal effects, such as the influence of visual cues on the perception of auditory cues, and the influence of cross-modal effects on the judgement of ``perceived presence'' and the rating of room acoustic quality.

  15. Interaction features for prediction of perceptual segmentation

    DEFF Research Database (Denmark)

    Hartmann, Martin; Lartillot, Olivier; Toiviainen, Petri

    2017-01-01

    As music unfolds in time, structure is recognised and understood by listeners, regardless of their level of musical expertise. A number of studies have found spectral and tonal changes to quite successfully model boundaries between structural sections. However, the effects of musical expertise...... and experimental task on computational modelling of structure are not yet well understood. These issues need to be addressed to better understand how listeners perceive the structure of music and to improve automatic segmentation algorithms. In this study, computational prediction of segmentation by listeners...... was investigated for six musical stimuli via a real-time task and an annotation (non real-time) task. The proposed approach involved computation of novelty curve interaction features and a prediction model of perceptual segmentation boundary density. We found that, compared to non-musicians’, musicians...

  16. Trial-dependent psychometric functions accounting for perceptual learning in 2-AFC discrimination tasks.

    Science.gov (United States)

    Kattner, Florian; Cochrane, Aaron; Green, C Shawn

    2017-09-01

    The majority of theoretical models of learning consider learning to be a continuous function of experience. However, most perceptual learning studies use thresholds estimated by fitting psychometric functions to independent blocks, sometimes then fitting a parametric function to these block-wise estimated thresholds. Critically, such approaches tend to violate the basic principle that learning is continuous through time (e.g., by aggregating trials into large "blocks" for analysis that each assume stationarity, then fitting learning functions to these aggregated blocks). To address this discrepancy between base theory and analysis practice, here we instead propose fitting a parametric function to thresholds from each individual trial. In particular, we implemented a dynamic psychometric function whose parameters were allowed to change continuously with each trial, thus parameterizing nonstationarity. We fit the resulting continuous time parametric model to data from two different perceptual learning tasks. In nearly every case, the quality of the fits derived from the continuous time parametric model outperformed the fits derived from a nonparametric approach wherein separate psychometric functions were fit to blocks of trials. Because such a continuous trial-dependent model of perceptual learning also offers a number of additional advantages (e.g., the ability to extrapolate beyond the observed data; the ability to estimate performance on individual critical trials), we suggest that this technique would be a useful addition to each psychophysicist's analysis toolkit.

  17. Similarity-based distortion of visual short-term memory is due to perceptual averaging.

    Science.gov (United States)

    Dubé, Chad; Zhou, Feng; Kahana, Michael J; Sekuler, Robert

    2014-03-01

    A task-irrelevant stimulus can distort recall from visual short-term memory (VSTM). Specifically, reproduction of a task-relevant memory item is biased in the direction of the irrelevant memory item (Huang & Sekuler, 2010a). The present study addresses the hypothesis that such effects reflect the influence of neural averaging under conditions of uncertainty about the contents of VSTM (Alvarez, 2011; Ball & Sekuler, 1980). We manipulated subjects' attention to relevant and irrelevant study items whose similarity relationships were held constant, while varying how similar the study items were to a subsequent recognition probe. On each trial, subjects were shown one or two Gabor patches, followed by the probe; their task was to indicate whether the probe matched one of the study items. A brief cue told subjects which Gabor, first or second, would serve as that trial's target item. Critically, this cue appeared either before, between, or after the study items. A distributional analysis of the resulting mnemometric functions showed an inflation in probability density in the region spanning the spatial frequency of the average of the two memory items. This effect, due to an elevation in false alarms to probes matching the perceptual average, was diminished when cues were presented before both study items. These results suggest that (a) perceptual averages are computed obligatorily and (b) perceptual averages are relied upon to a greater extent when item representations are weakened. Implications of these results for theories of VSTM are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. The perceptual effects of learning object categories that predict perceptual goals

    Science.gov (United States)

    Van Gulick, Ana E.; Gauthier, Isabel

    2014-01-01

    In classic category learning studies, subjects typically learn to assign items to one of two categories, with no further distinction between how items on each side of the category boundary should be treated. In real life, however, we often learn categories that dictate further processing goals, for instance with objects in only one category requiring further individuation. Using methods from category learning and perceptual expertise, we studied the perceptual consequences of experience with objects in tasks that rely on attention to different dimensions in different parts of the space. In two experiments, subjects first learned to categorize complex objects from a single morphspace into two categories based on one morph dimension, and then learned to perform a different task, either naming or a local feature judgment, for each of the two categories. A same-different discrimination test before and after each training measured sensitivity to feature dimensions of the space. After initial categorization, sensitivity increased along the category-diagnostic dimension. After task association, sensitivity increased more for the category that was named, especially along the non-diagnostic dimension. The results demonstrate that local attentional weights, associated with individual exemplars as a function of task requirements, can have lasting effects on perceptual representations. PMID:24820671

  19. Auditory Perceptual Learning for Speech Perception Can be Enhanced by Audiovisual Training.

    Science.gov (United States)

    Bernstein, Lynne E; Auer, Edward T; Eberhardt, Silvio P; Jiang, Jintao

    2013-01-01

    Speech perception under audiovisual (AV) conditions is well known to confer benefits to perception such as increased speed and accuracy. Here, we investigated how AV training might benefit or impede auditory perceptual learning of speech degraded by vocoding. In Experiments 1 and 3, participants learned paired associations between vocoded spoken nonsense words and nonsense pictures. In Experiment 1, paired-associates (PA) AV training of one group of participants was compared with audio-only (AO) training of another group. When tested under AO conditions, the AV-trained group was significantly more accurate than the AO-trained group. In addition, pre- and post-training AO forced-choice consonant identification with untrained nonsense words showed that AV-trained participants had learned significantly more than AO participants. The pattern of results pointed to their having learned at the level of the auditory phonetic features of the vocoded stimuli. Experiment 2, a no-training control with testing and re-testing on the AO consonant identification, showed that the controls were as accurate as the AO-trained participants in Experiment 1 but less accurate than the AV-trained participants. In Experiment 3, PA training alternated AV and AO conditions on a list-by-list basis within participants, and training was to criterion (92% correct). PA training with AO stimuli was reliably more effective than training with AV stimuli. We explain these discrepant results in terms of the so-called "reverse hierarchy theory" of perceptual learning and in terms of the diverse multisensory and unisensory processing resources available to speech perception. We propose that early AV speech integration can potentially impede auditory perceptual learning; but visual top-down access to relevant auditory features can promote auditory perceptual learning.

  20. The nature-disorder paradox: A perceptual study on how nature is disorderly yet aesthetically preferred.

    Science.gov (United States)

    Kotabe, Hiroki P; Kardan, Omid; Berman, Marc G

    2017-08-01

    Natural environments have powerful aesthetic appeal linked to their capacity for psychological restoration. In contrast, disorderly environments are aesthetically aversive, and have various detrimental psychological effects. But in our research, we have repeatedly found that natural environments are perceptually disorderly. What could explain this paradox? We present 3 competing hypotheses: the aesthetic preference for naturalness is more powerful than the aesthetic aversion to disorder (the nature-trumps-disorder hypothesis ); disorder is trivial to aesthetic preference in natural contexts (the harmless-disorder hypothesis ); and disorder is aesthetically preferred in natural contexts (the beneficial-disorder hypothesis ). Utilizing novel methods of perceptual study and diverse stimuli, we rule in the nature-trumps-disorder hypothesis and rule out the harmless-disorder and beneficial-disorder hypotheses. In examining perceptual mechanisms, we find evidence that high-level scene semantics are both necessary and sufficient for the nature-trumps-disorder effect. Necessity is evidenced by the effect disappearing in experiments utilizing only low-level visual stimuli (i.e., where scene semantics have been removed) and experiments utilizing a rapid-scene-presentation procedure that obscures scene semantics. Sufficiency is evidenced by the effect reappearing in experiments utilizing noun stimuli which remove low-level visual features. Furthermore, we present evidence that the interaction of scene semantics with low-level visual features amplifies the nature-trumps-disorder effect-the effect is weaker both when statistically adjusting for quantified low-level visual features and when using noun stimuli which remove low-level visual features. These results have implications for psychological theories bearing on the joint influence of low- and high-level perceptual inputs on affect and cognition, as well as for aesthetic design. (PsycINFO Database Record (c) 2017 APA, all

  1. Combining principles of Cognitive Load Theory and diagnostic error analysis for designing job aids: Effects on motivation and diagnostic performance in a process control task.

    Science.gov (United States)

    Kluge, Annette; Grauel, Britta; Burkolter, Dina

    2013-03-01

    Two studies are presented in which the design of a procedural aid and the impact of an additional decision aid for process control were assessed. In Study 1, a procedural aid was developed that avoids imposing unnecessary extraneous cognitive load on novices when controlling a complex technical system. This newly designed procedural aid positively affected germane load, attention, satisfaction, motivation, knowledge acquisition and diagnostic speed for novel faults. In Study 2, the effect of a decision aid for use before the procedural aid was investigated, which was developed based on an analysis of diagnostic errors committed in Study 1. Results showed that novices were able to diagnose both novel faults and practised faults, and were even faster at diagnosing novel faults. This research contributes to the question of how to optimally support novices in dealing with technical faults in process control. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  2. The theory of dissipative structures of the kinetic system for defects of nonlinear physical system 'metal+loading+irradiation'. Part 3

    International Nuclear Information System (INIS)

    Tarasov, V.A.; Borikov, T.L.; Kryzhanovskaya, T.V.; Chernezhenko, S.A.; Rusov, V.D.

    2007-01-01

    The kinetic system for defects of physical nonlinear system 'metal + load + irradiation' is specified [1, 2, 3]. Developing the approaches offered in [4], where distinctions of mechanisms of radiating creep and areas of their applicability are formalized (depending on external parameters) for fuel and constructional metals, division of kinetic systems for defects of constructional and fuel metals is carrying out. Thus the accent on the autocatalytic features of kinetic system for defects of reactor fuel metals, resulting from the exoenergic autocatalytic character of nuclear fission reactions being the main point defect source is done. In this part of the article the basic attention is given to the kinetic of sink drains for point defects. For kinetic systems of sinks-sources new approaches for the task of boundary conditions are offered. The possible structure of the computer program modelling kinetic system for defects of nonlinear physical system 'metal + load + irradiation' is considered

  3. Inductive generalization with familiar categories: developmental changes in children's reliance on perceptual similarity and kind information.

    Science.gov (United States)

    Godwin, Karrie E; Fisher, Anna V

    2015-01-01

    Inductive generalization is ubiquitous in human cognition; however, the factors underpinning this ability early in development remain contested. The present study was designed to (1) test the predictions of the naïve theory and a similarity-based account and (2) examine the mechanism by which labels promote induction. In Experiment 1, 3- to 5-year-old children made inferences about highly familiar categories. The results were not fully consistent with either theoretical account. In contrast to the predictions of the naïve theory approach, the youngest children in the study did not ignore perceptually compelling lures in favor of category-match items; in contrast to the predictions of the similarity-based account, no group of participants favored perceptually compelling lures in the presence of dissimilar-looking category-match items. In Experiment 2 we investigated the mechanisms by which labels promote induction by examining the influence of different label types, namely category labels (e.g., the target and category-match both labeled as bird) and descriptor labels (e.g., the target and the perceptual lure both labeled as brown) on induction performance. In contrast to the predictions of the naïve theory approach, descriptor labels but not category labels affected induction in 3-year-old children. Consistent with the predictions of the similarity-based account, descriptor labels affected the performance of children in all age groups included in the study. The implications of these findings for the developmental account of induction are discussed.

  4. Evaluating the Role of Attention in the Context of Unconscious Thought Theory: Differential Impact of Attentional Scope and Load on Preference and Memory

    OpenAIRE

    Srinivasan, Narayanan; Mukherjee, Sumitava; Mishra, Maruti V.; Kesarwani, Smriti

    2013-01-01

    Attention is a key process used to conceptualize and define modes of thought, but we lack information about the role of specific attentional processes on preferential choice and memory in multi-attribute decision making. In this study, we examine the role of attention based on two dimensions, attentional scope and load on choice preference strength and memory using a paradigm that arguably elicits unconscious thought. Scope of attention was manipulated by using global or local processing duri...

  5. Working memory load improves early stages of independent visual processing

    OpenAIRE

    Cocchi, Luca; Toepel, Ulrike; De Lucia, Marzia; Martuzzi, Roberto; Wood, Stephen J.; Carter, Olivia; Murray, Micah M.

    2010-01-01

    Increasing evidence suggests that working memory and perceptual processes are dynamically interrelated due to modulating activity in overlapping brain networks. However, the direct influence of working memory on the spatio-temporal brain dynamics of behaviorally relevant intervening information remains unclear. To investigate this issue, subjects performed a visual proximity grid perception task under three different visual-spatial working memory (VSWM) load conditions. VSWM load was manipula...

  6. 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.

  7. Structured perceptual input imposes an egocentric frame of reference-pointing, imagery, and spatial self-consciousness.

    Science.gov (United States)

    Marcel, Anthony; Dobel, Christian

    2005-01-01

    Perceptual input imposes and maintains an egocentric frame of reference, which enables orientation. When blindfolded, people tended to mistake the assumed intrinsic axes of symmetry of their immediate environment (a room) for their own egocentric relation to features of the room. When asked to point to the door and window, known to be at mid-points of facing (or adjacent) walls, they pointed with their arms at 180 degrees (or 90 degrees) angles, irrespective of where they thought they were in the room. People did the same when requested to imagine the situation. They justified their responses (inappropriately) by logical necessity or a structural description of the room rather than (appropriately) by relative location of themselves and the reference points. In eight experiments, we explored the effect on this in perception and imagery of: perceptual input (without perceptibility of the target reference points); imaging oneself versus another person; aids to explicit spatial self-consciousness; order of questions about self-location; and the relation of targets to the axes of symmetry of the room. The results indicate that, if one is deprived of structured perceptual input, as well as losing one's bearings, (a) one is likely to lose one's egocentric frame of reference itself, and (b) instead of pointing to reference points, one demonstrates their structural relation by adopting the intrinsic axes of the environment as one's own. This is prevented by providing noninformative perceptual input or by inducing subjects to imagine themselves from the outside, which makes explicit the fact of their being located relative to the world. The role of perceptual contact with a structured world is discussed in relation to sensory deprivation and imagery, appeal is made to Gibson's theory of joint egoreception and exteroception, and the data are related to recent theories of spatial memory and navigation.

  8. Five aspects of maximizing objectivity from perceptual evaluations of loudspeakers

    DEFF Research Database (Denmark)

    Volk, Christer Peter; Bech, Søren; Pedersen, Torben H.

    2015-01-01

    of data from the listening evaluations. This paper addresses the following subset of aspects for increasing the objectivity of data from listening tests: The choice of perceptual attributes, relevance of perceptual attributes, choice of loudness equalisation strategy, optimum listening room specifications......A literature study was conducted focusing on maximizing objectivity of results from listening evaluations aimed at establishing the relationship between physical and perceptual measurements of loudspeakers. The purpose of the study was to identify and examine factors influencing the objectivity......, as well as loudspeaker listening in-situ vs. listening to recordings of loudspeakers over headphones....

  9. Perceptual distortion analysis of color image VQ-based coding

    Science.gov (United States)

    Charrier, Christophe; Knoblauch, Kenneth; Cherifi, Hocine

    1997-04-01

    It is generally accepted that a RGB color image can be easily encoded by using a gray-scale compression technique on each of the three color planes. Such an approach, however, fails to take into account correlations existing between color planes and perceptual factors. We evaluated several linear and non-linear color spaces, some introduced by the CIE, compressed with the vector quantization technique for minimum perceptual distortion. To study these distortions, we measured contrast and luminance of the video framebuffer, to precisely control color. We then obtained psychophysical judgements to measure how well these methods work to minimize perceptual distortion in a variety of color space.

  10. Slippage theory and the flanker paradigm: an early-selection account of selective attention failures.

    Science.gov (United States)

    Gaspelin, Nicholas; Ruthruff, Eric; Jung, Kyunghun

    2014-06-01

    In the flanker paradigm, participants identify a target letter while attempting to ignore an irrelevant flanker. When the identity of this flanker mismatches the target, target identification is slowed (called the flanker compatibility effect). Interestingly, reducing the array set size greatly increases flanker compatibility effects. This finding inspired 2 prominent explanations: perceptual load (mandatory capacity spillover) and dilution (visual interference). However, an alternative explanation, based on early selection theory and attention capture research, can also explain the data pattern. According to this "slippage" account, observers sometimes accidentally allocate spatial attention to the flanker (see Lachter, Forster, & Ruthruff, 2004), especially when the flanker has the property used to find the target (cf. contingent capture). In Experiments 1 through 4, deterring slippage to the flanker nearly eliminated flanker compatibility effects, even at the low set size. In Experiment 5, promoting slippage to the flanker dramatically enhanced compatibility effects, even at the high set size. Thus, slippage strongly modulates flanker effects and can, by itself, readily explain the impact of set size. The perceptual load and dilution accounts are, at best, incomplete, and, at worst, not needed. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  11. Load forecasting

    International Nuclear Information System (INIS)

    Mak, H.

    1995-01-01

    Slides used in a presentation at The Power of Change Conference in Vancouver, BC in April 1995 about the changing needs for load forecasting were presented. Technological innovations and population increase were said to be the prime driving forces behind the changing needs in load forecasting. Structural changes, market place changes, electricity supply planning changes, and changes in planning objectives were other factors discussed. It was concluded that load forecasting was a form of information gathering, that provided important market intelligence

  12. Does perceptual learning require consciousness or attention?

    Science.gov (United States)

    Meuwese, Julia D I; Post, Ruben A G; Scholte, H Steven; Lamme, Victor A F

    2013-10-01

    It has been proposed that visual attention and consciousness are separate [Koch, C., & Tsuchiya, N. Attention and consciousness: Two distinct brain processes. Trends in Cognitive Sciences, 11, 16-22, 2007] and possibly even orthogonal processes [Lamme, V. A. F. Why visual attention and awareness are different. Trends in Cognitive Sciences, 7, 12-18, 2003]. Attention and consciousness converge when conscious visual percepts are attended and hence become available for conscious report. In such a view, a lack of reportability can have two causes: the absence of attention or the absence of a conscious percept. This raises an important question in the field of perceptual learning. It is known that learning can occur in the absence of reportability [Gutnisky, D. A., Hansen, B. J., Iliescu, B. F., & Dragoi, V. Attention alters visual plasticity during exposure-based learning. Current Biology, 19, 555-560, 2009; Seitz, A. R., Kim, D., & Watanabe, T. Rewards evoke learning of unconsciously processed visual stimuli in adult humans. Neuron, 61, 700-707, 2009; Seitz, A. R., & Watanabe, T. Is subliminal learning really passive? Nature, 422, 36, 2003; Watanabe, T., Náñez, J. E., & Sasaki, Y. Perceptual learning without perception. Nature, 413, 844-848, 2001], but it is unclear which of the two ingredients-consciousness or attention-is not necessary for learning. We presented textured figure-ground stimuli and manipulated reportability either by masking (which only interferes with consciousness) or with an inattention paradigm (which only interferes with attention). During the second session (24 hr later), learning was assessed neurally and behaviorally, via differences in figure-ground ERPs and via a detection task. Behavioral and neural learning effects were found for stimuli presented in the inattention paradigm and not for masked stimuli. Interestingly, the behavioral learning effect only became apparent when performance feedback was given on the task to measure learning

  13. Odor identification: perceptual and semantic dimensions.

    Science.gov (United States)

    Cain, W S; de Wijk, R; Lulejian, C; Schiet, F; See, L C

    1998-06-01

    Five studies explored identification of odors as an aspect of semantic memory. All dealt in one way or another with the accessibility of acquired olfactory information. The first study examined stability and showed that, consistent with personal reports, people can fail to identify an odor one day yet succeed another. Failure turned more commonly to success than vice versa, and once success occurred it tended to recur. Confidence ratings implied that subjects generally knew the quality of their answers. Even incorrect names, though, often carried considerable information which sometimes reflected a semantic and sometimes a perceptual source of errors. The second study showed that profiling odors via the American Society of Testing and Materials list of attributes, an exercise in depth of processing, effected no increment in the identifiability/accessibility beyond an unelaborated second attempt at retrieval. The third study showed that subjects had only a weak ability to predict the relative recognizability of odors they had failed to identify. Whereas the strength of the feeling that they would 'know' an answer if offered choices did not associate significantly with performance for odors, it did for trivia questions. The fourth study demonstrated an association between ability to discriminate among one set of odors and to identify another, but this emerged only after subjects had received feedback about identity, which essentially changed the task to one of recognition and effectively stabilized access. The fifth study illustrated that feedback improves performance dramatically only for odors involved with it, but that mere retrieval leads to some improvement. The studies suggest a research agenda that could include supplemental use of confidence judgments both retrospectively and prospectively in the same subjects to indicate the amount of accessible semantic information; use of second and third guesses to examine subjects' simultaneously held hypotheses about

  14. Review: Optimising cognitive load and usability to improve the ...

    African Journals Online (AJOL)

    Cognitive load theory views learning as involving active processing of information by working memory via separate visual and auditory channels. This system is of ... The fields of cognitive load theory and human-computer interaction share a common goal in striving to reduce extraneous cognitive load. The load induced by ...

  15. Modeling Dynamic Perceptual Attention in Complex Virtual Environments

    National Research Council Canada - National Science Library

    Kim, Youngjun; van Velsen, Martin; Hill, Jr, Randall W

    2005-01-01

    An important characteristic of a virtual human is the ability to direct its perceptual attention to entities and areas in a virtual environment in a manner that appears believable and serves a functional purpose...

  16. Memory: Enduring Traces of Perceptual and Reflective Attention

    Science.gov (United States)

    Chun, Marvin M.; Johnson, Marcia K.

    2011-01-01

    Attention and memory are typically studied as separate topics, but they are highly intertwined. Here we discuss the relation between memory and two fundamental types of attention: perceptual and reflective. Memory is the persisting consequence of cognitive activities initiated by and/or focused on external information from the environment (perceptual attention) and initiated by and/or focused on internal mental representations (reflective attention). We consider three key questions for advancing a cognitive neuroscience of attention and memory: To what extent do perception and reflection share representational areas? To what extent are the control processes that select, maintain, and manipulate perceptual and reflective information subserved by common areas and networks? During perception and reflection, to what extent are common areas responsible for binding features together to create complex, episodic memories and for reviving them later? Considering similarities and differences in perceptual and reflective attention helps integrate a broad range of findings and raises important unresolved issues. PMID:22099456

  17. Processing Consequences of Perceptual Grouping in Selective Attention.

    Science.gov (United States)

    Farkas, Mitchell S.; Hoyer, William J.

    1980-01-01

    Examined adult age differences in the effects of perceptual grouping on attentional performance. All three age groups were slowed by the presence of similar irrelevant information, but the elderly were slowed more than were the young adults. (Author)

  18. Perceptual tools for quality-aware video networks

    Science.gov (United States)

    Bovik, A. C.

    2014-01-01

    Monitoring and controlling the quality of the viewing experience of videos transmitted over increasingly congested networks (especially wireless networks) is a pressing problem owing to rapid advances in video-centric mobile communication and display devices that are straining the capacity of the network infrastructure. New developments in automatic perceptual video quality models offer tools that have the potential to be used to perceptually optimize wireless video, leading to more efficient video data delivery and better received quality. In this talk I will review key perceptual principles that are, or could be used to create effective video quality prediction models, and leading quality prediction models that utilize these principles. The goal is to be able to monitor and perceptually optimize video networks by making them "quality-aware."

  19. A new method for mapping perceptual biases across visual space.

    Science.gov (United States)

    Finlayson, Nonie J; Papageorgiou, Andriani; Schwarzkopf, D Samuel

    2017-08-01

    How we perceive the environment is not stable and seamless. Recent studies found that how a person qualitatively experiences even simple visual stimuli varies dramatically across different locations in the visual field. Here we use a method we developed recently that we call multiple alternatives perceptual search (MAPS) for efficiently mapping such perceptual biases across several locations. This procedure reliably quantifies the spatial pattern of perceptual biases and also of uncertainty and choice. We show that these measurements are strongly correlated with those from traditional psychophysical methods and that exogenous attention can skew biases without affecting overall task performance. Taken together, MAPS is an efficient method to measure how an individual's perceptual experience varies across space.

  20. PERCEPTUAL MAPPING BASED ON IDIOSYNCRATIC SETS OF ATTRIBUTES

    NARCIS (Netherlands)

    STEENKAMP, JBEM; VANTRIJP, HCM; TENBERGE, JMF

    The authors describe a compositional perceptual mapping procedure, unrestricted attribute-elicitation mapping (UAM), which allows consumers to describe and rate the brands in their own terminology and thus relaxes the restrictive assumptions of traditional compositional mapping techniques regarding