WorldWideScience

Sample records for single-target visual search

  1. Interrupted Visual Searches Reveal Volatile Search Memory

    Science.gov (United States)

    Shen, Y. Jeremy; Jiang, Yuhong V.

    2006-01-01

    This study investigated memory from interrupted visual searches. Participants conducted a change detection search task on polygons overlaid on scenes. Search was interrupted by various disruptions, including unfilled delay, passive viewing of other scenes, and additional search on new displays. Results showed that performance was unaffected by…

  2. Visual Representation Determines Search Difficulty: Explaining Visual Search Asymmetries

    Directory of Open Access Journals (Sweden)

    Neil eBruce

    2011-07-01

    Full Text Available In visual search experiments there exist a variety of experimental paradigms in which a symmetric set of experimental conditions yields asymmetric corresponding task performance. There are a variety of examples of this that currently lack a satisfactory explanation. In this paper, we demonstrate that distinct classes of asymmetries may be explained by virtue of a few simple conditions that are consistent with current thinking surrounding computational modeling of visual search and coding in the primate brain. This includes a detailed look at the role that stimulus familiarity plays in the determination of search performance. Overall, we demonstrate that all of these asymmetries have a common origin, namely, they are a consequence of the encoding that appears in the visual cortex. The analysis associated with these cases yields insight into the problem of visual search in general and predictions of novel search asymmetries.

  3. Visual search deficits in amblyopia.

    Science.gov (United States)

    Tsirlin, Inna; Colpa, Linda; Goltz, Herbert C; Wong, Agnes M F

    2018-04-01

    Amblyopia is a neurodevelopmental disorder defined as a reduction in visual acuity that cannot be corrected by optical means. It has been associated with low-level deficits. However, research has demonstrated a link between amblyopia and visual attention deficits in counting, tracking, and identifying objects. Visual search is a useful tool for assessing visual attention but has not been well studied in amblyopia. Here, we assessed the extent of visual search deficits in amblyopia using feature and conjunction search tasks. We compared the performance of participants with amblyopia (n = 10) to those of controls (n = 12) on both feature and conjunction search tasks using Gabor patch stimuli, varying spatial bandwidth and orientation. To account for the low-level deficits inherent in amblyopia, we measured individual contrast and crowding thresholds and monitored eye movements. The display elements were then presented at suprathreshold levels to ensure that visibility was equalized across groups. There was no performance difference between groups on feature search, indicating that our experimental design controlled successfully for low-level amblyopia deficits. In contrast, during conjunction search, median reaction times and reaction time slopes were significantly larger in participants with amblyopia compared with controls. Amblyopia differentially affects performance on conjunction visual search, a more difficult task that requires feature binding and possibly the involvement of higher-level attention processes. Deficits in visual search may affect day-to-day functioning in people with amblyopia.

  4. Learning in repeated visual search

    OpenAIRE

    Hout, Michael C.; Goldinger, Stephen D.

    2010-01-01

    Visual search (e.g., finding a specific object in an array of other objects) is performed most effectively when people are able to ignore distracting nontargets. In repeated search, however, incidental learning of object identities may facilitate performance. In three experiments, with over 1,100 participants, we examined the extent to which search could be facilitated by object memory and by memory for spatial layouts. Participants searched for new targets (real-world, nameable objects) embe...

  5. Learning in repeated visual search.

    Science.gov (United States)

    Hout, Michael C; Goldinger, Stephen D

    2010-07-01

    Visual search (e.g., finding a specific object in an array of other objects) is performed most effectively when people are able to ignore distracting nontargets. In repeated search, however, incidental learning of object identities may facilitate performance. In three experiments, with over 1,100 participants, we examined the extent to which search could be facilitated by object memory and by memory for spatial layouts. Participants searched for new targets (real-world, nameable objects) embedded among repeated distractors. To make the task more challenging, some participants performed search for multiple targets, increasing demands on visual working memory (WM). Following search, memory for search distractors was assessed using a surprise two-alternative forced choice recognition memory test with semantically matched foils. Search performance was facilitated by distractor object learning and by spatial memory; it was most robust when object identity was consistently tied to spatial locations and weakest (or absent) when object identities were inconsistent across trials. Incidental memory for distractors was better among participants who searched under high WM load, relative to low WM load. These results were observed when visual search included exhaustive-search trials (Experiment 1) or when all trials were self-terminating (Experiment 2). In Experiment 3, stimulus exposure was equated across WM load groups by presenting objects in a single-object stream; recognition accuracy was similar to that in Experiments 1 and 2. Together, the results suggest that people incidentally generate memory for nontarget objects encountered during search and that such memory can facilitate search performance.

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

    Science.gov (United States)

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

    2011-08-01

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

  7. Dual-target cost in visual search for multiple unfamiliar faces.

    Science.gov (United States)

    Mestry, Natalie; Menneer, Tamaryn; Cave, Kyle R; Godwin, Hayward J; Donnelly, Nick

    2017-08-01

    The efficiency of visual search for one (single-target) and either of two (dual-target) unfamiliar faces was explored to understand the manifestations of capacity and guidance limitations in face search. The visual similarity of distractor faces to target faces was manipulated using morphing (Experiments 1 and 2) and multidimensional scaling (Experiment 3). A dual-target cost was found in all experiments, evidenced by slower and less accurate search in dual- than single-target conditions. The dual-target cost was unequal across the targets, with performance being maintained on one target and reduced on the other, which we label "preferred" and "non-preferred" respectively. We calculated the capacity for each target face and show reduced capacity for representing the non-preferred target face. However, results show that the capacity for the non-preferred target can be increased when the dual-target condition is conducted after participants complete the single-target conditions. Analyses of eye movements revealed evidence for weak guidance of fixations in single-target search, and when searching for the preferred target in dual-target search. Overall, the experiments show dual-target search for faces is capacity- and guidance-limited, leading to superior search for 1 face over the other in dual-target search. However, learning faces individually may improve capacity with the second face. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  8. Interhemispheric integration in visual search.

    Science.gov (United States)

    Shipp, Stewart

    2011-07-01

    The search task of Luck, Hillyard, Mangun and Gazzaniga (1989) was optimised to test for the presence of a bilateral field advantage in the visual search capabilities of normal subjects. The modified design used geometrically regular arrays of 2, 4 or 8 items restricted to hemifields delineated by the vertical or horizontal meridian; the target, if present, appeared at one of two fixed positions per quadrant at an eccentricity of 11 deg. Group and individual performance data were analysed in terms of the slope of response time against display-size functions ('RT slope'). Averaging performance across all conditions save display mode (bilateral vs. unilateral) revealed a significant bilateral advantage in the form of a 21% increase in apparent item scanning speed for target detection; in the absence of a target, bilateral displays gave a 5% increase in speed that was not significant. Factor analysis by ANOVA confirmed this main effect of display mode, and also revealed several higher order interactions with display geometry, indicating that the bilateral advantage was masked at certain target positions by a crowding-like effect. In a numerical model of search efficiency (i.e. RT slope), bilateral advantage was parameterised by an interhemispheric 'transfer factor' (T) that governs the strength of the ipsilateral representation of distractors, and modifies the level of intrahemispheric competition with the target. The factor T was found to be higher in superior field than inferior field; this result held for the modelled data of each individual subject, as well as the group, representing a uniform tendency for the bilateral advantage to be more prominent in inferior field. In fact statistical analysis and modelling of search efficiency showed that the geometrical display factors (target polar and quadrantic location, and associated crowding effects) were all remarkably consistent across subjects. Greater variability was inferred within a fixed, decisional component of

  9. The development of organized visual search

    Science.gov (United States)

    Woods, Adam J.; Goksun, Tilbe; Chatterjee, Anjan; Zelonis, Sarah; Mehta, Anika; Smith, Sabrina E.

    2013-01-01

    Visual search plays an important role in guiding behavior. Children have more difficulty performing conjunction search tasks than adults. The present research evaluates whether developmental differences in children's ability to organize serial visual search (i.e., search organization skills) contribute to performance limitations in a typical conjunction search task. We evaluated 134 children between the ages of 2 and 17 on separate tasks measuring search for targets defined by a conjunction of features or by distinct features. Our results demonstrated that children organize their visual search better as they get older. As children's skills at organizing visual search improve they become more accurate at locating targets with conjunction of features amongst distractors, but not for targets with distinct features. Developmental limitations in children's abilities to organize their visual search of the environment are an important component of poor conjunction search in young children. In addition, our findings provide preliminary evidence that, like other visuospatial tasks, exposure to reading may influence children's spatial orientation to the visual environment when performing a visual search. PMID:23584560

  10. Eye Movements and Visual Search: A Bibliography,

    Science.gov (United States)

    1983-01-01

    Note 108, 1975. PSY 49 Barten, S., Birns, B., Rouch , J. Individual differences in the visual pursuit behaviour of neonates. Child Development, 1971, 42... Lee , I..C.; Fu, K.S. The QLGS iqa7e representation anc its alplication to preliminary seL-.entation and preattertive visual search. ILLE Computer

  11. Visualizing Search Behavior with Adaptive Discriminations

    OpenAIRE

    Cook, Robert G.; Qadri, Muhammad A. J.

    2013-01-01

    We examined different aspects of the visual search behavior of a pigeon using an open-ended, adaptive testing procedure controlled by a genetic algorithm. The animal had to accurately search for and peck a gray target element randomly located from among a variable number of surrounding darker and lighter distractor elements. Display composition was controlled by a genetic algorithm involving the multivariate configuration of different parameters or genes (number of distractors, element size, ...

  12. Searching in clutter : visual attention strategies of expert pilots

    Science.gov (United States)

    2012-10-22

    Clutter can slow visual search. However, experts may develop attention strategies that alleviate the effects of clutter on search performance. In the current study we examined the effects of global and local clutter on visual search performance and a...

  13. One visual search, many memory searches: An eye-tracking investigation of hybrid search.

    Science.gov (United States)

    Drew, Trafton; Boettcher, Sage E P; Wolfe, Jeremy M

    2017-09-01

    Suppose you go to the supermarket with a shopping list of 10 items held in memory. Your shopping expedition can be seen as a combination of visual search and memory search. This is known as "hybrid search." There is a growing interest in understanding how hybrid search tasks are accomplished. We used eye tracking to examine how manipulating the number of possible targets (the memory set size [MSS]) changes how observers (Os) search. We found that dwell time on each distractor increased with MSS, suggesting a memory search was being executed each time a new distractor was fixated. Meanwhile, although the rate of refixation increased with MSS, it was not nearly enough to suggest a strategy that involves repeatedly searching visual space for subgroups of the target set. These data provide a clear demonstration that hybrid search tasks are carried out via a "one visual search, many memory searches" heuristic in which Os examine items in the visual array once with a very low rate of refixations. For each item selected, Os activate a memory search that produces logarithmic response time increases with increased MSS. Furthermore, the percentage of distractors fixated was strongly modulated by the MSS: More items in the MSS led to a higher percentage of fixated distractors. Searching for more potential targets appears to significantly alter how Os approach the task, ultimately resulting in more eye movements and longer response times.

  14. Personalized online information search and visualization

    Directory of Open Access Journals (Sweden)

    Orthner Helmuth F

    2005-03-01

    Full Text Available Abstract Background The rapid growth of online publications such as the Medline and other sources raises the questions how to get the relevant information efficiently. It is important, for a bench scientist, e.g., to monitor related publications constantly. It is also important, for a clinician, e.g., to access the patient records anywhere and anytime. Although time-consuming, this kind of searching procedure is usually similar and simple. Likely, it involves a search engine and a visualization interface. Different words or combination reflects different research topics. The objective of this study is to automate this tedious procedure by recording those words/terms in a database and online sources, and use the information for an automated search and retrieval. The retrieved information will be available anytime and anywhere through a secure web server. Results We developed such a database that stored searching terms, journals and et al., and implement a piece of software for searching the medical subject heading-indexed sources such as the Medline and other online sources automatically. The returned information were stored locally, as is, on a server and visible through a Web-based interface. The search was performed daily or otherwise scheduled and the users logon to the website anytime without typing any words. The system has potentials to retrieve similarly from non-medical subject heading-indexed literature or a privileged information source such as a clinical information system. The issues such as security, presentation and visualization of the retrieved information were thus addressed. One of the presentation issues such as wireless access was also experimented. A user survey showed that the personalized online searches saved time and increased and relevancy. Handheld devices could also be used to access the stored information but less satisfactory. Conclusion The Web-searching software or similar system has potential to be an efficient

  15. Personalized online information search and visualization

    Science.gov (United States)

    Chen, Dongquan; Orthner, Helmuth F; Sell, Susan M

    2005-01-01

    Background The rapid growth of online publications such as the Medline and other sources raises the questions how to get the relevant information efficiently. It is important, for a bench scientist, e.g., to monitor related publications constantly. It is also important, for a clinician, e.g., to access the patient records anywhere and anytime. Although time-consuming, this kind of searching procedure is usually similar and simple. Likely, it involves a search engine and a visualization interface. Different words or combination reflects different research topics. The objective of this study is to automate this tedious procedure by recording those words/terms in a database and online sources, and use the information for an automated search and retrieval. The retrieved information will be available anytime and anywhere through a secure web server. Results We developed such a database that stored searching terms, journals and et al., and implement a piece of software for searching the medical subject heading-indexed sources such as the Medline and other online sources automatically. The returned information were stored locally, as is, on a server and visible through a Web-based interface. The search was performed daily or otherwise scheduled and the users logon to the website anytime without typing any words. The system has potentials to retrieve similarly from non-medical subject heading-indexed literature or a privileged information source such as a clinical information system. The issues such as security, presentation and visualization of the retrieved information were thus addressed. One of the presentation issues such as wireless access was also experimented. A user survey showed that the personalized online searches saved time and increased and relevancy. Handheld devices could also be used to access the stored information but less satisfactory. Conclusion The Web-searching software or similar system has potential to be an efficient tool for both bench scientists

  16. Top-down visual search in Wimmelbild

    Science.gov (United States)

    Bergbauer, Julia; Tari, Sibel

    2013-03-01

    Wimmelbild which means "teeming figure picture" is a popular genre of visual puzzles. Abundant masses of small figures are brought together in complex arrangements to make one scene in a Wimmelbild. It is picture hunt game. We discuss what type of computations/processes could possibly underlie the solution of the discovery of figures that are hidden due to a distractive influence of the context. One thing for sure is that the processes are unlikely to be purely bottom-up. One possibility is to re-arrange parts and see what happens. As this idea is linked to creativity, there are abundant examples of unconventional part re-organization in modern art. A second possibility is to define what to look for. That is to formulate the search as a top-down process. We address top-down visual search in Wimmelbild with the help of diffuse distance and curvature coding fields.

  17. Guided Text Search Using Adaptive Visual Analytics

    Energy Technology Data Exchange (ETDEWEB)

    Steed, Chad A [ORNL; Symons, Christopher T [ORNL; Senter, James K [ORNL; DeNap, Frank A [ORNL

    2012-10-01

    This research demonstrates the promise of augmenting interactive visualizations with semi- supervised machine learning techniques to improve the discovery of significant associations and insights in the search and analysis of textual information. More specifically, we have developed a system called Gryffin that hosts a unique collection of techniques that facilitate individualized investigative search pertaining to an ever-changing set of analytical questions over an indexed collection of open-source documents related to critical national infrastructure. The Gryffin client hosts dynamic displays of the search results via focus+context record listings, temporal timelines, term-frequency views, and multiple coordinate views. Furthermore, as the analyst interacts with the display, the interactions are recorded and used to label the search records. These labeled records are then used to drive semi-supervised machine learning algorithms that re-rank the unlabeled search records such that potentially relevant records are moved to the top of the record listing. Gryffin is described in the context of the daily tasks encountered at the US Department of Homeland Security s Fusion Center, with whom we are collaborating in its development. The resulting system is capable of addressing the analysts information overload that can be directly attributed to the deluge of information that must be addressed in the search and investigative analysis of textual information.

  18. Race Guides Attention in Visual Search.

    Directory of Open Access Journals (Sweden)

    Marte Otten

    Full Text Available It is known that faces are rapidly and even unconsciously categorized into social groups (black vs. white, male vs. female. Here, I test whether preferences for specific social groups guide attention, using a visual search paradigm. In Experiment 1 participants searched displays of neutral faces for an angry or frightened target face. Black target faces were detected more efficiently than white targets, indicating that black faces attracted more attention. Experiment 2 showed that attention differences between black and white faces were correlated with individual differences in automatic race preference. In Experiment 3, using happy target faces, the attentional preference for black over white faces was eliminated. Taken together, these results suggest that automatic preferences for social groups guide attention to individuals from negatively valenced groups, when people are searching for a negative emotion such as anger or fear.

  19. Reader error, object recognition, and visual search

    Science.gov (United States)

    Kundel, Harold L.

    2004-05-01

    Small abnormalities such as hairline fractures, lung nodules and breast tumors are missed by competent radiologists with sufficient frequency to make them a matter of concern to the medical community; not only because they lead to litigation but also because they delay patient care. It is very easy to attribute misses to incompetence or inattention. To do so may be placing an unjustified stigma on the radiologists involved and may allow other radiologists to continue a false optimism that it can never happen to them. This review presents some of the fundamentals of visual system function that are relevant to understanding the search for and the recognition of small targets embedded in complicated but meaningful backgrounds like chests and mammograms. It presents a model for visual search that postulates a pre-attentive global analysis of the retinal image followed by foveal checking fixations and eventually discovery scanning. The model will be used to differentiate errors of search, recognition and decision making. The implications for computer aided diagnosis and for functional workstation design are discussed.

  20. Adding a visualization feature to web search engines: it's time.

    Science.gov (United States)

    Wong, Pak Chung

    2008-01-01

    It's widely recognized that all Web search engines today are almost identical in presentation layout and behavior. In fact, the same presentation approach has been applied to depicting search engine results pages (SERPs) since the first Web search engine launched in 1993. In this Visualization Viewpoints article, I propose to add a visualization feature to Web search engines and suggest that the new addition can improve search engines' performance and capabilities, which in turn lead to better Web search technology.

  1. Visual search in unilateral spatial neglect: The effects of distractors on a dynamic visual search task.

    Science.gov (United States)

    Emerson, Rebeca Lauren; García-Molina, Alberto; López Carballo, Jaume; García Fernández, Juan; Aparicio-López, Celeste; Novo, Junquera; Sánchez-Carrión, Rocío; Enseñat-Cantallops, Antonia; Peña-Casanova, Jordi

    2018-02-22

    The objective of this study was to examine visual scanning performance in patients with Unilateral Spatial Neglect (USN) in a visual search task. Thirty-one right hemisphere stroke patients with USN were recruited. They performed a dynamic visual search task with two conditions, with and without distractors, while eye movements were monitored with an eye-tracker. The main goal of the task was to select target stimuli that appeared from the top of the screen and moved vertically downward. Target detection and visual scanning percentage were assessed over two hemispaces (right, left) on two conditions (distractor, no distractor). Most Scanned Regions (MSR) were calculated to analyze the areas of the screen where most points of fixation were directed to. Higher target detection rate and visual scanning percentages were found on the right hemispace on both conditions. From the MSRs we found that participants with a center of attention further to the right of the screen also presented smaller overall MSRs. Right hemisphere stroke patients with USN presented not only a significant rightward bias but reduced overall search areas, implying hyperattention does not only restrict search on the horizontal (right-left) axis but the vertical axis (top-bottom) too.

  2. Usability Testing of a Large, Multidisciplinary Library Database: Basic Search and Visual Search

    Directory of Open Access Journals (Sweden)

    Jody Condit Fagan

    2006-09-01

    Full Text Available Visual search interfaces have been shown by researchers to assist users with information search and retrieval. Recently, several major library vendors have added visual search interfaces or functions to their products. For public service librarians, perhaps the most critical area of interest is the extent to which visual search interfaces and text-based search interfaces support research. This study presents the results of eight full-scale usability tests of both the EBSCOhost Basic Search and Visual Search in the context of a large liberal arts university.

  3. A ?snapshot? of the visual search behaviours of medical sonographers

    OpenAIRE

    Carrigan, Ann J; Brennan, Patrick C; Pietrzyk, Mariusz; Clarke, Jillian; Chekaluk, Eugene

    2015-01-01

    Abstract Introduction: Visual search is a task that humans perform in everyday life. Whether it involves looking for a pen on a desk or a mass in a mammogram, the cognitive and perceptual processes that underpin these tasks are identical. Radiologists are experts in visual search of medical images and studies on their visual search behaviours have revealed some interesting findings with regard to diagnostic errors. In Australia, within the modality of ultrasound, sonographers perform the diag...

  4. Priming and the guidance by visual and categorical templates in visual search

    NARCIS (Netherlands)

    Wilschut, A.M.; Theeuwes, J.; Olivers, C.N.L.

    2014-01-01

    Visual search is thought to be guided by top-down templates that are held in visual working memory. Previous studies have shown that a search-guiding template can be rapidly and strongly implemented from a visual cue, whereas templates are less effective when based on categorical cues. Direct visual

  5. The prevalence effect in lateral masking and its relevance for visual search.

    Science.gov (United States)

    Geelen, B P; Wertheim, A H

    2015-04-01

    In stimulus displays with or without a single target amid 1,644 identical distractors, target prevalence was varied between 20, 50 and 80 %. Maximum gaze deviation was measured to determine the strength of lateral masking in these arrays. The results show that lateral masking was strongest in the 20 % prevalence condition, which differed significantly from both the 50 and 80 % prevalence conditions. No difference was observed between the latter two. This pattern of results corresponds to that found in the literature on the prevalence effect in visual search (stronger lateral masking corresponding to longer search times). The data add to similar findings reported earlier (Wertheim et al. in Exp Brain Res, 170:387-402, 2006), according to which the effects of many well-known factors in visual search correspond to those on lateral masking. These were the effects of set size, disjunctions versus conjunctions, display area, distractor density, the asymmetry effect (Q vs. O's) and viewing distance. The present data, taken together with those earlier findings, may lend credit to a causal hypothesis that lateral masking could be a more important mechanism in visual search than usually assumed.

  6. Reward and Attentional Control in Visual Search

    Science.gov (United States)

    Anderson, Brian A.; Wampler, Emma K.; Laurent, Patryk A.

    2015-01-01

    It has long been known that the control of attention in visual search depends both on voluntary, top-down deployment according to context-specific goals, and on involuntary, stimulus-driven capture based on the physical conspicuity of perceptual objects. Recent evidence suggests that pairing target stimuli with reward can modulate the voluntary deployment of attention, but there is little evidence that reward modulates the involuntary deployment of attention to task-irrelevant distractors. We report several experiments that investigate the role of reward learning on attentional control. Each experiment involved a training phase and a test phase. In the training phase, different colors were associated with different amounts of monetary reward. In the test phase, color was not task-relevant and participants searched for a shape singleton; in most experiments no reward was delivered in the test phase. We first show that attentional capture by physically salient distractors is magnified by a previous association with reward. In subsequent experiments we demonstrate that physically inconspicuous stimuli previously associated with reward capture attention persistently during extinction—even several days after training. Furthermore, vulnerability to attentional capture by high-value stimuli is negatively correlated across individuals with working memory capacity and positively correlated with trait impulsivity. An analysis of intertrial effects reveals that value-driven attentional capture is spatially specific. Finally, when reward is delivered at test contingent on the task-relevant shape feature, recent reward history modulates value-driven attentional capture by the irrelevant color feature. The influence of learned value on attention may provide a useful model of clinical syndromes characterized by similar failures of cognitive control, including addiction, attention-deficit/hyperactivity disorder, and obesity. PMID:23437631

  7. The target effect: visual memory for unnamed search targets.

    Science.gov (United States)

    Thomas, Mark D; Williams, Carrick C

    2014-01-01

    Search targets are typically remembered much better than other objects even when they are viewed for less time. However, targets have two advantages that other objects in search displays do not have: They are identified categorically before the search, and finding them represents the goal of the search task. The current research investigated the contributions of both of these types of information to the long-term visual memory representations of search targets. Participants completed either a predefined search or a unique-object search in which targets were not defined with specific categorical labels before searching. Subsequent memory results indicated that search target memory was better than distractor memory even following ambiguously defined searches and when the distractors were viewed significantly longer. Superior target memory appears to result from a qualitatively different representation from those of distractor objects, indicating that decision processes influence visual memory.

  8. Eye Movements Reveal How Task Difficulty Moulds Visual Search

    Science.gov (United States)

    Young, Angela H.; Hulleman, Johan

    2013-01-01

    In two experiments we investigated the relationship between eye movements and performance in visual search tasks of varying difficulty. Experiment 1 provided evidence that a single process is used for search among static and moving items. Moreover, we estimated the functional visual field (FVF) from the gaze coordinates and found that its size…

  9. Visual Search Deficits Are Independent of Magnocellular Deficits in Dyslexia

    Science.gov (United States)

    Wright, Craig M.; Conlon, Elizabeth G.; Dyck, Murray

    2012-01-01

    The aim of this study was to investigate the theory that visual magnocellular deficits seen in groups with dyslexia are linked to reading via the mechanisms of visual attention. Visual attention was measured with a serial search task and magnocellular function with a coherent motion task. A large group of children with dyslexia (n = 70) had slower…

  10. Visual search in barn owls: Task difficulty and saccadic behavior.

    Science.gov (United States)

    Orlowski, Julius; Ben-Shahar, Ohad; Wagner, Hermann

    2018-01-01

    How do we find what we are looking for? A target can be in plain view, but it may be detected only after extensive search. During a search we make directed attentional deployments like saccades to segment the scene until we detect the target. Depending on difficulty, the search may be fast with few attentional deployments or slow with many, shorter deployments. Here we study visual search in barn owls by tracking their overt attentional deployments-that is, their head movements-with a camera. We conducted a low-contrast feature search, a high-contrast orientation conjunction search, and a low-contrast orientation conjunction search, each with set sizes varying from 16 to 64 items. The barn owls were able to learn all of these tasks and showed serial search behavior. In a subsequent step, we analyzed how search behavior of owls changes with search complexity. We compared the search mechanisms in these three serial searches with results from pop-out searches our group had reported earlier. Saccade amplitude shortened and fixation duration increased in difficult searches. Also, in conjunction search saccades were guided toward items with shared target features. These data suggest that during visual search, barn owls utilize mechanisms similar to those that humans use.

  11. Words, Shape, Visual Search and Visual Working Memory in 3-Year-Old Children

    Science.gov (United States)

    Vales, Catarina; Smith, Linda B.

    2015-01-01

    Do words cue children's visual attention, and if so, what are the relevant mechanisms? Across four experiments, 3-year-old children (N = 163) were tested in visual search tasks in which targets were cued with only a visual preview versus a visual preview and a spoken name. The experiments were designed to determine whether labels facilitated…

  12. The Effect of Stress on Crossmodal Interference During Visual Search

    National Research Council Canada - National Science Library

    Burton, P. A; Morelli, F

    2006-01-01

    .... Using a response competition paradigm, the present study examined how induced stress influences crossmodal links with respect to perceptual load in a visual search task under conditions of no stress...

  13. Numerosity estimates for attended and unattended items in visual search.

    Science.gov (United States)

    Kelley, Troy D; Cassenti, Daniel N; Marusich, Laura R; Ghirardelli, Thomas G

    2017-07-01

    The goal of this research was to examine memories created for the number of items during a visual search task. Participants performed a visual search task for a target defined by a single feature (Experiment 1A), by a conjunction of features (Experiment 1B), or by a specific spatial configuration of features (Experiment 1C). On some trials following the search task, subjects were asked to recall the total number of items in the previous display. In all search types, participants underestimated the total number of items, but the severity of the underestimation varied depending on the efficiency of the search. In three follow-up studies (Experiments 2A, 2B, and 2C) using the same visual stimuli, the participants' only task was to estimate the number of items on each screen. Participants still underestimated the numerosity of the items, although the degree of underestimation was smaller than in the search tasks and did not depend on the type of visual stimuli. In Experiment 3, participants were asked to recall the number of items in a display only once. Subjects still displayed a tendency to underestimate, indicating that the underestimation effects seen in Experiments 1A-1C were not attributable to knowledge of the estimation task. The degree of underestimation depends on the efficiency of the search task, with more severe underestimation in efficient search tasks. This suggests that the lower attentional demands of very efficient searches leads to less encoding of numerosity of the distractor set.

  14. Exposure to arousal-inducing sounds facilitates visual search.

    Science.gov (United States)

    Asutay, Erkin; Västfjäll, Daniel

    2017-09-04

    Exposure to affective stimuli could enhance perception and facilitate attention via increasing alertness, vigilance, and by decreasing attentional thresholds. However, evidence on the impact of affective sounds on perception and attention is scant. Here, a novel aspect of affective facilitation of attention is studied: whether arousal induced by task-irrelevant auditory stimuli could modulate attention in a visual search. In two experiments, participants performed a visual search task with and without auditory-cues that preceded the search. Participants were faster in locating high-salient targets compared to low-salient targets. Critically, search times and search slopes decreased with increasing auditory-induced arousal while searching for low-salient targets. Taken together, these findings suggest that arousal induced by sounds can facilitate attention in a subsequent visual search. This novel finding provides support for the alerting function of the auditory system by showing an auditory-phasic alerting effect in visual attention. The results also indicate that stimulus arousal modulates the alerting effect. Attention and perception are our everyday tools to navigate our surrounding world and the current findings showing that affective sounds could influence visual attention provide evidence that we make use of affective information during perceptual processing.

  15. Visual Search by Children with and without ADHD

    Science.gov (United States)

    Mullane, Jennifer C.; Klein, Raymond M.

    2008-01-01

    Objective: To summarize the literature that has employed visual search tasks to assess automatic and effortful selective visual attention in children with and without ADHD. Method: Seven studies with a combined sample of 180 children with ADHD (M age = 10.9) and 193 normally developing children (M age = 10.8) are located. Results: Using a…

  16. How important is lateral masking in visual search?

    NARCIS (Netherlands)

    Wertheim, AH; Hooge, ITC; Krikke, K; Johnson, A

    Five experiments are presented, providing empirical support of the hypothesis that the sensory phenomenon of lateral masking may explain many well-known visual search phenomena that are commonly assumed to be governed by cognitive attentional mechanisms. Experiment I showed that when the same visual

  17. Visual Approach of Searching Process using Boyer-Moore Algorithm

    Science.gov (United States)

    Rahim, Robbi; Saleh Ahmar, Ansari; Putri Ardyanti, Ayu; Nofriansyah, Dicky

    2017-12-01

    This research shows the process of string matching using a Boyer-Moore algorithm in the form of visual simulation by doing string searching of a pattern string, the result of visualization is recognized that Boyer-Moore algorithm will compare a n string from the right and will test to n-1 String to get the appropriate character of the desired input string.

  18. Changing Perspective: Zooming in and out during Visual Search

    Science.gov (United States)

    Solman, Grayden J. F.; Cheyne, J. Allan; Smilek, Daniel

    2013-01-01

    Laboratory studies of visual search are generally conducted in contexts with a static observer vantage point, constrained by a fixation cross or a headrest. In contrast, in many naturalistic search settings, observers freely adjust their vantage point by physically moving through space. In two experiments, we evaluate behavior during free vantage…

  19. Identifying a "default" visual search mode with operant conditioning.

    Science.gov (United States)

    Kawahara, Jun-ichiro

    2010-09-01

    The presence of a singleton in a task-irrelevant domain can impair visual search. This impairment, known as the attentional capture depends on the set of participants. When narrowly searching for a specific feature (the feature search mode), only matching stimuli capture attention. When searching broadly (the singleton detection mode), any oddball captures attention. The present study examined which strategy represents the "default" mode using an operant conditioning approach in which participants were trained, in the absence of explicit instructions, to search for a target in an ambiguous context in which one of two modes was available. The results revealed that participants behaviorally adopted the singleton detection as the default mode but reported using the feature search mode. Conscious strategies did not eliminate capture. These results challenge the view that a conscious set always modulates capture, suggesting that the visual system tends to rely on stimulus salience to deploy attention.

  20. Probing the Feature Map for Faces in Visual Search

    Directory of Open Access Journals (Sweden)

    Hua Yang

    2011-05-01

    Full Text Available Controversy surrounds the mechanisms underlying the pop-out effect for faces in visual search. Is there a feature map for faces? If so, does it rely on the categorical distinction between faces and nonfaces, or on image-level face semblance? To probe the feature map, we compared search efficiency for faces, and nonface stimuli with high, low, and no face semblance. First, subjects performed a visual search task with objects as distractors. Only faces popped-out. Moreover, search efficiency for nonfaces correlated with image-level face semblance of the target. In a second experiment, faces were used as distractors but nonfaces did not pop-out. Interestingly, search efficiency for nonfaces was not modulated by face semblance, although searching for a face among faces was particularly difficult, reflecting a categorical boundary between nonfaces and faces. Finally, inversion and contrast negation significantly interacted with the effect of face semblance, ruling out the possibility that search efficiency solely depends on low-level features. Our study supports a parallel search for faces that is perhaps preattentive. Like other features (color, orientation etc., there appears to be a continuous face feature map for visual search. Our results also suggest that this map may include both image-level face semblance and face categoricity.

  1. A 'snapshot' of the visual search behaviours of medical sonographers.

    Science.gov (United States)

    Carrigan, Ann J; Brennan, Patrick C; Pietrzyk, Mariusz; Clarke, Jillian; Chekaluk, Eugene

    2015-05-01

    Introduction : Visual search is a task that humans perform in everyday life. Whether it involves looking for a pen on a desk or a mass in a mammogram, the cognitive and perceptual processes that underpin these tasks are identical. Radiologists are experts in visual search of medical images and studies on their visual search behaviours have revealed some interesting findings with regard to diagnostic errors. In Australia, within the modality of ultrasound, sonographers perform the diagnostic scan, select images and present to the radiologist for reporting. Therefore the visual task and potential for errors is similar to a radiologist. Our aim was to explore and understand the detection, localisation and eye-gaze behaviours of a group of qualified sonographers. Method : We measured clinical performance and analysed diagnostic errors by presenting fifty sonographic breast images that varied on cancer present and degree of difficulty to a group of sonographers in their clinical workplace. For a sub-set of sonographers we obtained eye-tracking metrics such as time-to-first fixation, total visit duration and cumulative dwell time heat maps. Results : The results indicate that the sonographers' clinical performance was high and the eye-tracking metrics showed diagnostic error types similar to those found in studies on radiologist visual search. Conclusion : This study informs us about sonographer visual search patterns and highlights possible ways to improve diagnostic performance via targeted education.

  2. LoyalTracker: Visualizing Loyalty Dynamics in Search Engines.

    Science.gov (United States)

    Shi, Conglei; Wu, Yingcai; Liu, Shixia; Zhou, Hong; Qu, Huamin

    2014-12-01

    The huge amount of user log data collected by search engine providers creates new opportunities to understand user loyalty and defection behavior at an unprecedented scale. However, this also poses a great challenge to analyze the behavior and glean insights into the complex, large data. In this paper, we introduce LoyalTracker, a visual analytics system to track user loyalty and switching behavior towards multiple search engines from the vast amount of user log data. We propose a new interactive visualization technique (flow view) based on a flow metaphor, which conveys a proper visual summary of the dynamics of user loyalty of thousands of users over time. Two other visualization techniques, a density map and a word cloud, are integrated to enable analysts to gain further insights into the patterns identified by the flow view. Case studies and the interview with domain experts are conducted to demonstrate the usefulness of our technique in understanding user loyalty and switching behavior in search engines.

  3. Does linear separability really matter? Complex visual search is explained by simple search

    Science.gov (United States)

    Vighneshvel, T.; Arun, S. P.

    2013-01-01

    Visual search in real life involves complex displays with a target among multiple types of distracters, but in the laboratory, it is often tested using simple displays with identical distracters. Can complex search be understood in terms of simple searches? This link may not be straightforward if complex search has emergent properties. One such property is linear separability, whereby search is hard when a target cannot be separated from its distracters using a single linear boundary. However, evidence in favor of linear separability is based on testing stimulus configurations in an external parametric space that need not be related to their true perceptual representation. We therefore set out to assess whether linear separability influences complex search at all. Our null hypothesis was that complex search performance depends only on classical factors such as target-distracter similarity and distracter homogeneity, which we measured using simple searches. Across three experiments involving a variety of artificial and natural objects, differences between linearly separable and nonseparable searches were explained using target-distracter similarity and distracter heterogeneity. Further, simple searches accurately predicted complex search regardless of linear separability (r = 0.91). Our results show that complex search is explained by simple search, refuting the widely held belief that linear separability influences visual search. PMID:24029822

  4. Individual differences and metacognitive knowledge of visual search strategy.

    Directory of Open Access Journals (Sweden)

    Michael J Proulx

    Full Text Available A crucial ability for an organism is to orient toward important objects and to ignore temporarily irrelevant objects. Attention provides the perceptual selectivity necessary to filter an overwhelming input of sensory information to allow for efficient object detection. Although much research has examined visual search and the 'template' of attentional set that allows for target detection, the behavior of individual subjects often reveals the limits of experimental control of attention. Few studies have examined important aspects such as individual differences and metacognitive strategies. The present study analyzes the data from two visual search experiments for a conjunctively defined target (Proulx, 2007. The data revealed attentional capture blindness, individual differences in search strategies, and a significant rate of metacognitive errors for the assessment of the strategies employed. These results highlight a challenge for visual attention studies to account for individual differences in search behavior and distractibility, and participants that do not (or are unable to follow instructions.

  5. Priming and the guidance by visual and categorical templates in visual search

    Directory of Open Access Journals (Sweden)

    Anna eWilschut

    2014-02-01

    Full Text Available Visual search is thought to be guided by top-down templates that are held in visual working memory. Previous studies have shown that a search-guiding template can be rapidly and strongly implemented from a visual cue, whereas templates are less effective when based on categorical cues. Direct visual priming from cue to target may underlie this difference. In two experiments we first asked observers to remember two possible target colors. A postcue then indicated which of the two would be the relevant color. The task was to locate a briefly presented and masked target of the cued color among irrelevant distractor items. Experiment 1 showed that overall search accuracy improved more rapidly on the basis of a direct visual postcue that carried the target color, compared to a neutral postcue that pointed to the memorized color. However, selectivity towards the target feature, i.e. the extent to which observers searched selectively among items of the cued versus uncued color, was found to be relatively unaffected by the presence of the visual signal. In Experiment 2 we compared search that was based on either visual or categorical information, but now controlled for direct visual priming. This resulted in no differences in overall performance nor selectivity. Altogether the results suggest that perceptual processing of visual search targets is facilitated by priming from visual cues, whereas attentional selectivity is enhanced by a working memory template that can formed from both visual and categorical input. Furthermore, if the priming is controlled for, categorical- and visual-based templates similarly enhance search guidance.

  6. Visual search tasks: measurement of dynamic visual lobe and relationship with display movement velocity.

    Science.gov (United States)

    Yang, Lin-Dong; Yu, Rui-Feng; Lin, Xue-Lian; Xie, Ya-Qing; Ma, Liang

    2018-02-01

    Visual lobe is a useful tool for predicting visual search performance. Up till now, no study has focused on dynamic visual lobe. This study developed a dynamic visual lobe measurement system (DVLMS) that could effectively map dynamic visual lobe and calculate visual lobe shape indices. The effects of display movement velocity on lobe shape indices were examined under four velocity conditions: 0, 4, 8 and 16 deg/s. In general, with the increase of display movement velocity, visual lobe area and perimeter became smaller, whereas lobe shape roundness, boundary smoothness, symmetry and regularity deteriorated. The elongation index was not affected by velocity. Regression analyses indicated that display movement velocity was important in determining dynamic visual lobe shape indices. Dynamic visual lobe provides another option for better understanding dynamic vision, in addition to dynamic visual acuity. Findings of this study can provide guidelines for analysing and designing dynamic visual tasks. Practitioner Summary: Dynamic visual lobe is important in reflecting the visual ability of searching for a moving target. We developed a dynamic visual lobe measurement system (DVLMS) and examined display movement velocity's effects on lobe shape. Findings revealed that velocity was a key factor affecting dynamic visual lobe shape indices.

  7. Target-nontarget similarity decreases search efficiency and increases stimulus-driven control in visual search.

    Science.gov (United States)

    Barras, Caroline; Kerzel, Dirk

    2017-10-01

    Some points of criticism against the idea that attentional selection is controlled by bottom-up processing were dispelled by the attentional window account. The attentional window account claims that saliency computations during visual search are only performed for stimuli inside the attentional window. Therefore, a small attentional window may avoid attentional capture by salient distractors because it is likely that the salient distractor is located outside the window. In contrast, a large attentional window increases the chances of attentional capture by a salient distractor. Large and small attentional windows have been associated with efficient (parallel) and inefficient (serial) search, respectively. We compared the effect of a salient color singleton on visual search for a shape singleton during efficient and inefficient search. To vary search efficiency, the nontarget shapes were either similar or dissimilar with respect to the shape singleton. We found that interference from the color singleton was larger with inefficient than efficient search, which contradicts the attentional window account. While inconsistent with the attentional window account, our results are predicted by computational models of visual search. Because of target-nontarget similarity, the target was less salient with inefficient than efficient search. Consequently, the relative saliency of the color distractor was higher with inefficient than with efficient search. Accordingly, stronger attentional capture resulted. Overall, the present results show that bottom-up control by stimulus saliency is stronger when search is difficult, which is inconsistent with the attentional window account.

  8. History effects in visual search for monsters: search times, choice biases, and liking.

    Science.gov (United States)

    Chetverikov, Andrey; Kristjansson, Árni

    2015-02-01

    Repeating targets and distractors on consecutive visual search trials facilitates search performance, whereas switching targets and distractors harms search. In addition, search repetition leads to biases in free choice tasks, in that previously attended targets are more likely to be chosen than distractors. Another line of research has shown that attended items receive high liking ratings, whereas ignored distractors are rated negatively. Potential relations between the three effects are unclear, however. Here we simultaneously measured repetition benefits and switching costs for search times, choice biases, and liking ratings in color singleton visual search for "monster" shapes. We showed that if expectations from search repetition are violated, targets are liked to be less attended than otherwise. Choice biases were, on the other hand, affected by distractor repetition, but not by target/distractor switches. Target repetition speeded search times but had little influence on choice or liking. Our findings suggest that choice biases reflect distractor inhibition, and liking reflects the conflict associated with attending to previously inhibited stimuli, while speeded search follows both target and distractor repetition. Our results support the newly proposed affective-feedback-of-hypothesis-testing account of cognition, and additionally, shed new light on the priming of visual search.

  9. Visual search by chimpanzees (Pan): assessment of controlling relations.

    Science.gov (United States)

    Tomonaga, M

    1995-03-01

    Three experimentally sophisticated chimpanzees (Pan), Akira, Chloe, and Ai, were trained on visual search performance using a modified multiple-alternative matching-to-sample task in which a sample stimulus was followed by the search display containing one target identical to the sample and several uniform distractors (i.e., negative comparison stimuli were identical to each other). After they acquired this task, they were tested for transfer of visual search performance to trials in which the sample was not followed by the uniform search display (odd-item search). Akira showed positive transfer of visual search performance to odd-item search even when the display size (the number of stimulus items in the search display) was small, whereas Chloe and Ai showed a transfer only when the display size was large. Chloe and Ai used some nonrelational cues such as perceptual isolation of the target among uniform distractors (so-called pop-out). In addition to the odd-item search test, various types of probe trials were presented to clarify the controlling relations in multiple-alternative matching to sample. Akira showed a decrement of accuracy as a function of the display size when the search display was nonuniform (i.e., each "distractor" stimulus was not the same), whereas Chloe and Ai showed perfect performance. Furthermore, when the sample was identical to the uniform distractors in the search display, Chloe and Ai never selected an odd-item target, but Akira selected it when the display size was large. These results indicated that Akira's behavior was controlled mainly by relational cues of target-distractor oddity, whereas an identity relation between the sample and the target strongly controlled the performance of Chloe and Ai.

  10. Rapid Resumption of Interrupted Search Is Independent of Age-Related Improvements in Visual Search

    Science.gov (United States)

    Lleras, Alejandro; Porporino, Mafalda; Burack, Jacob A.; Enns, James T.

    2011-01-01

    In this study, 7-19-year-olds performed an interrupted visual search task in two experiments. Our question was whether the tendency to respond within 500 ms after a second glimpse of a display (the "rapid resumption" effect ["Psychological Science", 16 (2005) 684-688]) would increase with age in the same way as overall search efficiency. The…

  11. Searching while loaded: Visual working memory does not interfere with hybrid search efficiency but hybrid search uses working memory capacity.

    Science.gov (United States)

    Drew, Trafton; Boettcher, Sage E P; Wolfe, Jeremy M

    2016-02-01

    In "hybrid search" tasks, such as finding items on a grocery list, one must search the scene for targets while also searching the list in memory. How is the representation of a visual item compared with the representations of items in the memory set? Predominant theories would propose a role for visual working memory (VWM) either as the site of the comparison or as a conduit between visual and memory systems. In seven experiments, we loaded VWM in different ways and found little or no effect on hybrid search performance. However, the presence of a hybrid search task did reduce the measured capacity of VWM by a constant amount regardless of the size of the memory or visual sets. These data are broadly consistent with an account in which VWM must dedicate a fixed amount of its capacity to passing visual representations to long-term memory for comparison to the items in the memory set. The data cast doubt on models in which the search template resides in VWM or where memory set item representations are moved from LTM through VWM to earlier areas for comparison to visual items.

  12. Synaesthetic colours do not camouflage form in visual search.

    Science.gov (United States)

    Gheri, C; Chopping, S; Morgan, M J

    2008-04-07

    One of the major issues in synaesthesia research is to identify the level of processing involved in the formation of the subjective colours experienced by synaesthetes: are they perceptual phenomena or are they due to memory and association learning? To address this question, we tested whether the colours reported by a group of grapheme-colour synaesthetes (previously studied in an functional magnetic resonance imaging experiment) influenced them in a visual search task. As well as using a condition where synaesthetic colours should have aided visual search, we introduced a condition where the colours experienced by synaesthetes would be expected to make them worse than controls. We found no evidence for differences between synaesthetes and normal controls, either when colours should have helped them or where they should have hindered. We conclude that the colours reported by our population of synaesthetes are not equivalent to perceptual signals, but arise at a cognitive level where they are unable to affect visual search.

  13. Short-term perceptual learning in visual conjunction search.

    Science.gov (United States)

    Su, Yuling; Lai, Yunpeng; Huang, Wanyi; Tan, Wei; Qu, Zhe; Ding, Yulong

    2014-08-01

    Although some studies showed that training can improve the ability of cross-dimension conjunction search, less is known about the underlying mechanism. Specifically, it remains unclear whether training of visual conjunction search can successfully bind different features of separated dimensions into a new function unit at early stages of visual processing. In the present study, we utilized stimulus specificity and generalization to provide a new approach to investigate the mechanisms underlying perceptual learning (PL) in visual conjunction search. Five experiments consistently showed that after 40 to 50 min of training of color-shape/orientation conjunction search, the ability to search for a certain conjunction target improved significantly and the learning effects did not transfer to a new target that differed from the trained target in both color and shape/orientation features. However, the learning effects were not strictly specific. In color-shape conjunction search, although the learning effect could not transfer to a same-shape different-color target, it almost completely transferred to a same-color different-shape target. In color-orientation conjunction search, the learning effect partly transferred to a new target that shared same color or same orientation with the trained target. Moreover, the sum of transfer effects for the same color target and the same orientation target in color-orientation conjunction search was algebraically equivalent to the learning effect for trained target, showing an additive transfer effect. The different transfer patterns in color-shape and color-orientation conjunction search learning might reflect the different complexity and discriminability between feature dimensions. These results suggested a feature-based attention enhancement mechanism rather than a unitization mechanism underlying the short-term PL of color-shape/orientation conjunction search.

  14. Adaptation to a simulated central scotoma during visual search training.

    Science.gov (United States)

    Walsh, David V; Liu, Lei

    2014-03-01

    Patients with a central scotoma usually use a preferred retinal locus (PRL) consistently in daily activities. The selection process and time course of the PRL development are not well understood. We used a gaze-contingent display to simulate an isotropic central scotoma in normal subjects while they were practicing a difficult visual search task. As compared to foveal search, initial exposure to the simulated scotoma resulted in prolonged search reaction time, many more fixations and unorganized eye movements during search. By the end of a 1782-trial training with the simulated scotoma, the search performance improved to within 25% of normal foveal search. Accompanying the performance improvement, there were also fewer fixations, fewer repeated fixations in the same area of the search stimulus and a clear tendency of using one area near the border of the scotoma to identify the search target. The results were discussed in relation to natural development of PRL in central scotoma patients and potential visual training protocols to facilitate PRL development. Published by Elsevier Ltd.

  15. Visual exploratory search of relationship graphs on smartphones.

    Directory of Open Access Journals (Sweden)

    Jianquan Ouyang

    Full Text Available This paper presents a novel framework for Visual Exploratory Search of Relationship Graphs on Smartphones (VESRGS that is composed of three major components: inference and representation of semantic relationship graphs on the Web via meta-search, visual exploratory search of relationship graphs through both querying and browsing strategies, and human-computer interactions via the multi-touch interface and mobile Internet on smartphones. In comparison with traditional lookup search methodologies, the proposed VESRGS system is characterized with the following perceived advantages. 1 It infers rich semantic relationships between the querying keywords and other related concepts from large-scale meta-search results from Google, Yahoo! and Bing search engines, and represents semantic relationships via graphs; 2 the exploratory search approach empowers users to naturally and effectively explore, adventure and discover knowledge in a rich information world of interlinked relationship graphs in a personalized fashion; 3 it effectively takes the advantages of smartphones' user-friendly interfaces and ubiquitous Internet connection and portability. Our extensive experimental results have demonstrated that the VESRGS framework can significantly improve the users' capability of seeking the most relevant relationship information to their own specific needs. We envision that the VESRGS framework can be a starting point for future exploration of novel, effective search strategies in the mobile Internet era.

  16. Visual exploratory search of relationship graphs on smartphones.

    Science.gov (United States)

    Ouyang, Jianquan; Zheng, Hao; Kong, Fanbin; Liu, Tianming

    2013-01-01

    This paper presents a novel framework for Visual Exploratory Search of Relationship Graphs on Smartphones (VESRGS) that is composed of three major components: inference and representation of semantic relationship graphs on the Web via meta-search, visual exploratory search of relationship graphs through both querying and browsing strategies, and human-computer interactions via the multi-touch interface and mobile Internet on smartphones. In comparison with traditional lookup search methodologies, the proposed VESRGS system is characterized with the following perceived advantages. 1) It infers rich semantic relationships between the querying keywords and other related concepts from large-scale meta-search results from Google, Yahoo! and Bing search engines, and represents semantic relationships via graphs; 2) the exploratory search approach empowers users to naturally and effectively explore, adventure and discover knowledge in a rich information world of interlinked relationship graphs in a personalized fashion; 3) it effectively takes the advantages of smartphones' user-friendly interfaces and ubiquitous Internet connection and portability. Our extensive experimental results have demonstrated that the VESRGS framework can significantly improve the users' capability of seeking the most relevant relationship information to their own specific needs. We envision that the VESRGS framework can be a starting point for future exploration of novel, effective search strategies in the mobile Internet era.

  17. Cognitive psychology: rare items often missed in visual searches.

    Science.gov (United States)

    Wolfe, Jeremy M; Horowitz, Todd S; Kenner, Naomi M

    2005-05-26

    Our society relies on accurate performance in visual screening tasks--for example, to detect knives in luggage or tumours in mammograms. These are visual searches for rare targets. We show here that target rarity leads to disturbingly inaccurate performance in target detection: if observers do not find what they are looking for fairly frequently, they often fail to notice it when it does appear.

  18. More than a memory: Confirmatory visual search is not caused by remembering a visual feature.

    Science.gov (United States)

    Rajsic, Jason; Pratt, Jay

    2017-10-01

    Previous research has demonstrated a preference for positive over negative information in visual search; asking whether a target object is green biases search towards green objects, even when this entails more perceptual processing than searching non-green objects. The present study investigated whether this confirmatory search bias is due to the presence of one particular (e.g., green) color in memory during search. Across two experiments, we show that this is not the critical factor in generating a confirmation bias in search. Search slowed proportionally to the number of stimuli whose color matched the color held in memory only when the color was remembered as part of the search instructions. These results suggest that biased search for information is due to a particular attentional selection strategy, and not to memory-driven attentional biases. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Visual search for arbitrary objects in real scenes

    Science.gov (United States)

    Alvarez, George A.; Rosenholtz, Ruth; Kuzmova, Yoana I.; Sherman, Ashley M.

    2011-01-01

    How efficient is visual search in real scenes? In searches for targets among arrays of randomly placed distractors, efficiency is often indexed by the slope of the reaction time (RT) × Set Size function. However, it may be impossible to define set size for real scenes. As an approximation, we hand-labeled 100 indoor scenes and used the number of labeled regions as a surrogate for set size. In Experiment 1, observers searched for named objects (a chair, bowl, etc.). With set size defined as the number of labeled regions, search was very efficient (~5 ms/item). When we controlled for a possible guessing strategy in Experiment 2, slopes increased somewhat (~15 ms/item), but they were much shallower than search for a random object among other distinctive objects outside of a scene setting (Exp. 3: ~40 ms/item). In Experiments 4–6, observers searched repeatedly through the same scene for different objects. Increased familiarity with scenes had modest effects on RTs, while repetition of target items had large effects (>500 ms). We propose that visual search in scenes is efficient because scene-specific forms of attentional guidance can eliminate most regions from the “functional set size” of items that could possibly be the target. PMID:21671156

  20. The role of memory for visual search in scenes.

    Science.gov (United States)

    Le-Hoa Võ, Melissa; Wolfe, Jeremy M

    2015-03-01

    Many daily activities involve looking for something. The ease with which these searches are performed often allows one to forget that searching represents complex interactions between visual attention and memory. Although a clear understanding exists of how search efficiency will be influenced by visual features of targets and their surrounding distractors or by the number of items in the display, the role of memory in search is less well understood. Contextual cueing studies have shown that implicit memory for repeated item configurations can facilitate search in artificial displays. When searching more naturalistic environments, other forms of memory come into play. For instance, semantic memory provides useful information about which objects are typically found where within a scene, and episodic scene memory provides information about where a particular object was seen the last time a particular scene was viewed. In this paper, we will review work on these topics, with special emphasis on the role of memory in guiding search in organized, real-world scenes. © 2015 New York Academy of Sciences.

  1. Crowded visual search in children with normal vision and children with visual impairment

    NARCIS (Netherlands)

    Huurneman, Bianca; Cox, Ralf F. A.; Vlaskamp, Björn N. S.; Boonstra, F. Nienke

    This study investigates the influence of oculomotor control, crowding, and attentional factors on visual search in children with normal vision ([NV], n = 11), children with visual impairment without nystagmus ([VI-nys], n = 11), and children with VI with accompanying nystagmus ([VI+nys], n = 26).

  2. The long and the short of priming in visual search

    NARCIS (Netherlands)

    Kruijne, W.; Meeter, M.

    2015-01-01

    Memory affects visual search, as is particularly evident from findings that when target features are repeated from one trial to the next, selection is faster. Two views have emerged on the nature of the memory representations and mechanisms that cause these intertrial priming effects: independent

  3. Visual search, anticipation and expertise in soccer goalkeepers

    NARCIS (Netherlands)

    Savelsbergh, G.J.P.; Williams, A.M.; van der Kamp, J.; Ward, P.

    2002-01-01

    We used a novel methodological approach to examine skill-based differences in anticipation and visual search behaviour during the penalty kick in soccer. Expert and novice goalkeepers were required to move a joystick in response to penalty kicks presented on film. The proportion of penalties saved

  4. A review: search visualization with Knuth Morris Pratt algorithm

    Science.gov (United States)

    Rahim, Robbi; Zulkarnain, Iskandar; Jaya, Hendra

    2017-09-01

    In this research modeled a search process of the Knuth-Morris-Pratt algorithm in the form of easy-to-understand visualization, Knuth-Morris-Pratt algorithm selection because this algorithm is easy to learn and easy to implement into many programming languages.

  5. The Development of Visual Search Strategies in Biscriptal Readers.

    Science.gov (United States)

    Liow, Susan Rikard; Green, David; Tam, Melissa

    1999-01-01

    To test whether cognitive processing in bilingual depends on script combinations and language proficiency, this study investigated the development of alphabetic and logographic visual search strategies in two kinds of biscriptals: (1) Malay-English and (2) Chinese-English readers. Results support the view that there are script implications of…

  6. Anticipation and visual search behaviour in expert soccer goalkeepers

    NARCIS (Netherlands)

    Savelsbergh, G.J.P.; van der Kamp, J.; Williams, A.M.; Ward, P.

    2005-01-01

    A novel methodological approach is presented to examine the visual search behaviours employed by expert goalkeepers during simulated penalty kick situations in soccer. Expert soccer goalkeepers were classified as successful or unsuccessful based on their performance on a film-based test of

  7. 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.

  8. 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.

  9. Interaction between numbers and size during visual search.

    Science.gov (United States)

    Krause, Florian; Bekkering, Harold; Pratt, Jay; Lindemann, Oliver

    2017-05-01

    The current study investigates an interaction between numbers and physical size (i.e. size congruity) in visual search. In three experiments, participants had to detect a physically large (or small) target item among physically small (or large) distractors in a search task comprising single-digit numbers. The relative numerical size of the digits was varied, such that the target item was either among the numerically large or small numbers in the search display and the relation between numerical and physical size was either congruent or incongruent. Perceptual differences of the stimuli were controlled by a condition in which participants had to search for a differently coloured target item with the same physical size and by the usage of LCD-style numbers that were matched in visual similarity by shape transformations. The results of all three experiments consistently revealed that detecting a physically large target item is significantly faster when the numerical size of the target item is large as well (congruent), compared to when it is small (incongruent). This novel finding of a size congruity effect in visual search demonstrates an interaction between numerical and physical size in an experimental setting beyond typically used binary comparison tasks, and provides important new evidence for the notion of shared cognitive codes for numbers and sensorimotor magnitudes. Theoretical consequences for recent models on attention, magnitude representation and their interactions are discussed.

  10. Visualization for Information Retrieval based on Fast Search Technology

    Directory of Open Access Journals (Sweden)

    Mamoon H. Mamoon

    2013-03-01

    Full Text Available The core of search engine is information retrieval technique. Using information retrieval system backs more retrieval results, some of them more relevant than other, and some is not relevant. While using search engine to retrieve information has grown very substantially, there remain problems with the information retrieval systems. The interface of the systems does not help them to perceive the precision of these results. It is therefore not surprising that graphical visualizations have been employed in search engines to assist users. The main objective of Internet users is to find the required information with high efficiency and effectiveness. In this paper we present brief sides of information visualization's role in enhancing web information retrieval system as in some of its techniques such as tree view, title view, map view, bubble view and cloud view and its tools such as highlighting and Colored Query Result.

  11. Behavior and neural basis of near-optimal visual search

    Science.gov (United States)

    Ma, Wei Ji; Navalpakkam, Vidhya; Beck, Jeffrey M; van den Berg, Ronald; Pouget, Alexandre

    2013-01-01

    The ability to search efficiently for a target in a cluttered environment is one of the most remarkable functions of the nervous system. This task is difficult under natural circumstances, as the reliability of sensory information can vary greatly across space and time and is typically a priori unknown to the observer. In contrast, visual-search experiments commonly use stimuli of equal and known reliability. In a target detection task, we randomly assigned high or low reliability to each item on a trial-by-trial basis. An optimal observer would weight the observations by their trial-to-trial reliability and combine them using a specific nonlinear integration rule. We found that humans were near-optimal, regardless of whether distractors were homogeneous or heterogeneous and whether reliability was manipulated through contrast or shape. We present a neural-network implementation of near-optimal visual search based on probabilistic population coding. The network matched human performance. PMID:21552276

  12. Temporal Stability of Visual Search-Driven Biometrics

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hong-Jun [ORNL; Carmichael, Tandy [Tennessee Technological University; Tourassi, Georgia [ORNL

    2015-01-01

    Previously, we have shown the potential of using an individual s visual search pattern as a possible biometric. That study focused on viewing images displaying dot-patterns with different spatial relationships to determine which pattern can be more effective in establishing the identity of an individual. In this follow-up study we investigated the temporal stability of this biometric. We performed an experiment with 16 individuals asked to search for a predetermined feature of a random-dot pattern as we tracked their eye movements. Each participant completed four testing sessions consisting of two dot patterns repeated twice. One dot pattern displayed concentric circles shifted to the left or right side of the screen overlaid with visual noise, and participants were asked which side the circles were centered on. The second dot-pattern displayed a number of circles (between 0 and 4) scattered on the screen overlaid with visual noise, and participants were asked how many circles they could identify. Each session contained 5 untracked tutorial questions and 50 tracked test questions (200 total tracked questions per participant). To create each participant s "fingerprint", we constructed a Hidden Markov Model (HMM) from the gaze data representing the underlying visual search and cognitive process. The accuracy of the derived HMM models was evaluated using cross-validation for various time-dependent train-test conditions. Subject identification accuracy ranged from 17.6% to 41.8% for all conditions, which is significantly higher than random guessing (1/16 = 6.25%). The results suggest that visual search pattern is a promising, fairly stable personalized fingerprint of perceptual organization.

  13. Visual search characteristics in mammography: malignant vs benign breast masses

    Science.gov (United States)

    Mello-Thoms, Claudia

    2007-03-01

    Mammography screening is the most widely utilized tool to screen for breast cancer. Radiologists read a mammogram using a two-pass strategy where the first pass is guided by salient features of the image (the so-called 'pop-out' elements), and the second pass is a systematic search. It is assumed that most breast masses that are reported by the radiologist are in fact detected during the first pass of this search strategy, and that the second pass is useful for the detection of microcalcification clusters. Furthermore, experiments in other visual domains have shown that observers are attracted faster to incongruous elements in a display than to normal (i.e., more expected) elements. In this sense, it can be argued that benign findings constitute more expected findings, because they encompass a large percentage of all abnormalities found on a mammogram. In this experiment we sought to determine whether the search for malignant masses was indeed faster than the search for benign masses. We also aimed to determine whether the observers' overall visual search behavior was different between benign and malignant cases, not only in terms of how long it took the observers to hit the location of the lesion, but also how long the observers took analyzing the case, how different the distribution of false positive responses were between the two types of cases, etc.

  14. Prior knowledge of category size impacts visual search.

    Science.gov (United States)

    Wu, Rachel; McGee, Brianna; Echiverri, Chelsea; Zinszer, Benjamin D

    2018-03-30

    Prior research has shown that category search can be similar to one-item search (as measured by the N2pc ERP marker of attentional selection) for highly familiar, smaller categories (e.g., letters and numbers) because the finite set of items in a category can be grouped into one unit to guide search. Other studies have shown that larger, more broadly defined categories (e.g., healthy food) also can elicit N2pc components during category search, but the amplitude of these components is typically attenuated. Two experiments investigated whether the perceived size of a familiar category impacts category and exemplar search. We presented participants with 16 familiar company logos: 8 from a smaller category (social media companies) and 8 from a larger category (entertainment/recreation manufacturing companies). The ERP results from Experiment 1 revealed that, in a two-item search array, search was more efficient for the smaller category of logos compared to the larger category. In a four-item search array (Experiment 2), where two of the four items were placeholders, search was largely similar between the category types, but there was more attentional capture by nontarget members from the same category as the target for smaller rather than larger categories. These results support a growing literature on how prior knowledge of categories affects attentional selection and capture during visual search. We discuss the implications of these findings in relation to assessing cognitive abilities across the lifespan, given that prior knowledge typically increases with age. © 2018 Society for Psychophysiological Research.

  15. Aurally Aided Visual Search Performance Comparing Virtual Audio Systems

    DEFF Research Database (Denmark)

    Larsen, Camilla Horne; Lauritsen, David Skødt; Larsen, Jacob Junker

    2014-01-01

    Due to increased computational power reproducing binaural hearing in real-time applications, through usage of head-related transfer functions (HRTFs), is now possible. This paper addresses the differences in aurally-aided visual search performance between an HRTF enhanced audio system (3D...... with white dots. The results indicate that 3D audio yields faster search latencies than panning audio, especially with larger amounts of distractors. The applications of this research could fit virtual environments such as video games or virtual simulations....

  16. Aurally Aided Visual Search Performance Comparing Virtual Audio Systems

    DEFF Research Database (Denmark)

    Larsen, Camilla Horne; Lauritsen, David Skødt; Larsen, Jacob Junker

    2014-01-01

    Due to increased computational power, reproducing binaural hearing in real-time applications, through usage of head-related transfer functions (HRTFs), is now possible. This paper addresses the differences in aurally-aided visual search performance between a HRTF enhanced audio system (3D...... with white dots. The results indicate that 3D audio yields faster search latencies than panning audio, especially with larger amounts of distractors. The applications of this research could fit virtual environments such as video games or virtual simulations....

  17. Object detection through search with a foveated visual system.

    Directory of Open Access Journals (Sweden)

    Emre Akbas

    2017-10-01

    Full Text Available Humans and many other species sense visual information with varying spatial resolution across the visual field (foveated vision and deploy eye movements to actively sample regions of interests in scenes. The advantage of such varying resolution architecture is a reduced computational, hence metabolic cost. But what are the performance costs of such processing strategy relative to a scheme that processes the visual field at high spatial resolution? Here we first focus on visual search and combine object detectors from computer vision with a recent model of peripheral pooling regions found at the V1 layer of the human visual system. We develop a foveated object detector that processes the entire scene with varying resolution, uses retino-specific object detection classifiers to guide eye movements, aligns its fovea with regions of interest in the input image and integrates observations across multiple fixations. We compared the foveated object detector against a non-foveated version of the same object detector which processes the entire image at homogeneous high spatial resolution. We evaluated the accuracy of the foveated and non-foveated object detectors identifying 20 different objects classes in scenes from a standard computer vision data set (the PASCAL VOC 2007 dataset. We show that the foveated object detector can approximate the performance of the object detector with homogeneous high spatial resolution processing while bringing significant computational cost savings. Additionally, we assessed the impact of foveation on the computation of bottom-up saliency. An implementation of a simple foveated bottom-up saliency model with eye movements showed agreement in the selection of top salient regions of scenes with those selected by a non-foveated high resolution saliency model. Together, our results might help explain the evolution of foveated visual systems with eye movements as a solution that preserves perceptual performance in visual

  18. Crowded visual search in children with normal vision and children with visual impairment.

    Science.gov (United States)

    Huurneman, Bianca; Cox, Ralf F A; Vlaskamp, Björn N S; Boonstra, F Nienke

    2014-03-01

    This study investigates the influence of oculomotor control, crowding, and attentional factors on visual search in children with normal vision ([NV], n=11), children with visual impairment without nystagmus ([VI-nys], n=11), and children with VI with accompanying nystagmus ([VI+nys], n=26). Exclusion criteria for children with VI were: multiple impairments and visual acuity poorer than 20/400 or better than 20/50. Three search conditions were presented: a row with homogeneous distractors, a matrix with homogeneous distractors, and a matrix with heterogeneous distractors. Element spacing was manipulated in 5 steps from 2 to 32 minutes of arc. Symbols were sized 2 times the threshold acuity to guarantee visibility for the VI groups. During simple row and matrix search with homogeneous distractors children in the VI+nys group were less accurate than children with NV at smaller spacings. Group differences were even more pronounced during matrix search with heterogeneous distractors. Search times were longer in children with VI compared to children with NV. The more extended impairments during serial search reveal greater dependence on oculomotor control during serial compared to parallel search. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Synaesthetic colours do not camouflage form in visual search

    OpenAIRE

    Gheri, C; Chopping, S; Morgan, M.J

    2008-01-01

    One of the major issues in synaesthesia research is to identify the level of processing involved in the formation of the subjective colours experienced by synaesthetes: are they perceptual phenomena or are they due to memory and association learning? To address this question, we tested whether the colours reported by a group of grapheme-colour synaesthetes (previously studied in an functional magnetic resonance imaging experiment) influenced them in a visual search task. As well as using a co...

  20. Visual Fashion-Product Search at SK Planet

    OpenAIRE

    Kim, Taewan; Kim, Seyeong; Na, Sangil; Kim, Hayoon; Kim, Moonki; Jeon, Byoung-Ki

    2016-01-01

    We build a large-scale visual search system which finds similar product images given a fashion item. Defining similarity among arbitrary fashion-products is still remains a challenging problem, even there is no exact ground-truth. To resolve this problem, we define more than 90 fashion-related attributes, and combination of these attributes can represent thousands of unique fashion-styles. The fashion-attributes are one of the ingredients to define semantic similarity among fashion-product im...

  1. Reading and visual search: a developmental study in normal children.

    Directory of Open Access Journals (Sweden)

    Magali Seassau

    Full Text Available Studies dealing with developmental aspects of binocular eye movement behaviour during reading are scarce. In this study we have explored binocular strategies during reading and during visual search tasks in a large population of normal young readers. Binocular eye movements were recorded using an infrared video-oculography system in sixty-nine children (aged 6 to 15 and in a group of 10 adults (aged 24 to 39. The main findings are (i in both tasks the number of progressive saccades (to the right and regressive saccades (to the left decreases with age; (ii the amplitude of progressive saccades increases with age in the reading task only; (iii in both tasks, the duration of fixations as well as the total duration of the task decreases with age; (iv in both tasks, the amplitude of disconjugacy recorded during and after the saccades decreases with age; (v children are significantly more accurate in reading than in visual search after 10 years of age. Data reported here confirms and expands previous studies on children's reading. The new finding is that younger children show poorer coordination than adults, both while reading and while performing a visual search task. Both reading skills and binocular saccades coordination improve with age and children reach a similar level to adults after the age of 10. This finding is most likely related to the fact that learning mechanisms responsible for saccade yoking develop during childhood until adolescence.

  2. Visual search reveals a critical component to shape.

    Science.gov (United States)

    Dickinson, J Edwin; Haley, Krystle; Bowden, Vanessa K; Badcock, David R

    2018-02-01

    Objects are often identified by the shape of their contours. In this study, visual search tasks were used to reveal a visual dimension critical to the analysis of the shape of a boundary-defined area. Points of maximum curvature on closed paths are important for shape coding and it was shown here that target patterns are readily identified among distractors if the angle subtended by adjacent curvature maxima at the target pattern's center differs from that created in the distractors. A search asymmetry, indicated by a difference in performance in the visual search task when the roles of target and distractor patterns are reversed, was found when the critical subtended angle was only present in one of the patterns. Performance for patterns with the same subtended angle but differing local orientation and curvature was poor, demonstrating insensitivity to differences in these local features of the patterns. These results imply that the discrimination of objects by the shape of their boundaries relies on the relative positions of their curvature maxima rather than the local properties of the boundary from which these positions are derived.

  3. Visual Information and Support Surface for Postural Control in Visual Search Task.

    Science.gov (United States)

    Huang, Chia-Chun; Yang, Chih-Mei

    2016-10-01

    When standing on a reduced support surface, people increase their reliance on visual information to control posture. This assertion was tested in the current study. The effects of imposed motion and support surface on postural control during visual search were investigated. Twelve participants (aged 21 ± 1.8 years; six men and six women) stood on a reduced support surface (45% base of support). In a room that moved back and forth along the anteroposterior axis, participants performed visual search for a given letter in an article. Postural sway variability and head-room coupling were measured. The results of head-room coupling, but not postural sway, supported the assertion that people increase reliance on visual information when standing on a reduced support surface. Whether standing on a whole or reduced surface, people stabilized their posture to perform the visual search tasks. Compared to a fixed target, searching on a hand-held target showed greater head-room coupling when standing on a reduced surface. © The Author(s) 2016.

  4. Influence of scene structure and content on visual search strategies.

    Science.gov (United States)

    Amor, Tatiana A; Luković, Mirko; Herrmann, Hans J; Andrade, José S

    2017-07-01

    When searching for a target within an image, our brain can adopt different strategies, but which one does it choose? This question can be answered by tracking the motion of the eye while it executes the task. Following many individuals performing various search tasks, we distinguish between two competing strategies. Motivated by these findings, we introduce a model that captures the interplay of the search strategies and allows us to create artificial eye-tracking trajectories, which could be compared with the experimental ones. Identifying the model parameters allows us to quantify the strategy employed in terms of ensemble averages, characterizing each experimental cohort. In this way, we can discern with high sensitivity the relation between the visual landscape and the average strategy, disclosing how small variations in the image induce changes in the strategy. © 2017 The Author(s).

  5. Visual working memory simultaneously guides facilitation and inhibition during visual search.

    Science.gov (United States)

    Dube, Blaire; Basciano, April; Emrich, Stephen M; Al-Aidroos, Naseem

    2016-07-01

    During visual search, visual working memory (VWM) supports the guidance of attention in two ways: It stores the identity of the search target, facilitating the selection of matching stimuli in the search array, and it maintains a record of the distractors processed during search so that they can be inhibited. In two experiments, we investigated whether the full contents of VWM can be used to support both of these abilities simultaneously. In Experiment 1, participants completed a preview search task in which (a) a subset of search distractors appeared before the remainder of the search items, affording participants the opportunity to inhibit them, and (b) the search target varied from trial to trial, requiring the search target template to be maintained in VWM. We observed the established signature of VWM-based inhibition-reduced ability to ignore previewed distractors when the number of distractors exceeds VWM's capacity-suggesting that VWM can serve this role while also representing the target template. In Experiment 2, we replicated Experiment 1, but added to the search displays a singleton distractor that sometimes matched the color (a task-irrelevant feature) of the search target, to evaluate capture. We again observed the signature of VWM-based preview inhibition along with attentional capture by (and, thus, facilitation of) singletons matching the target template. These findings indicate that more than one VWM representation can bias attention at a time, and that these representations can separately affect selection through either facilitation or inhibition, placing constraints on existing models of the VWM-based guidance of attention.

  6. Visual Search Performance in Patients with Vision Impairment: A Systematic Review.

    Science.gov (United States)

    Senger, Cassia; Margarido, Maria Rita Rodrigues Alves; De Moraes, Carlos Gustavo; De Fendi, Ligia Issa; Messias, André; Paula, Jayter Silva

    2017-11-01

    Patients with visual impairment are constantly facing challenges to achieve an independent and productive life, which depends upon both a good visual discrimination and search capacities. Given that visual search is a critical skill for several daily tasks and could be used as an index of the overall visual function, we investigated the relationship between vision impairment and visual search performance. A comprehensive search was undertaken using electronic PubMed, EMBASE, LILACS, and Cochrane databases from January 1980 to December 2016, applying the following terms: "visual search", "visual search performance", "visual impairment", "visual exploration", "visual field", "hemianopia", "search time", "vision lost", "visual loss", and "low vision". Two hundred seventy six studies from 12,059 electronic database files were selected, and 40 of them were included in this review. Studies included participants of all ages, both sexes, and the sample sizes ranged from 5 to 199 participants. Visual impairment was associated with worse visual search performance in several ophthalmologic conditions, which were either artificially induced, or related to specific eye and neurological diseases. This systematic review details all the described circumstances interfering with visual search tasks, highlights the need for developing technical standards, and outlines patterns for diagnosis and therapy using visual search capabilities.

  7. Information-Limited Parallel Processing in Difficult Heterogeneous Covert Visual Search

    Science.gov (United States)

    Dosher, Barbara Anne; Han, Songmei; Lu, Zhong-Lin

    2010-01-01

    Difficult visual search is often attributed to time-limited serial attention operations, although neural computations in the early visual system are parallel. Using probabilistic search models (Dosher, Han, & Lu, 2004) and a full time-course analysis of the dynamics of covert visual search, we distinguish unlimited capacity parallel versus serial…

  8. Visual search and eye movements in novel and familiar contexts

    Science.gov (United States)

    McDermott, Kyle; Mulligan, Jeffrey B.; Bebis, George; Webster, Michael A.

    2006-02-01

    Adapting to the visual characteristics of a specific environment may facilitate detecting novel stimuli within that environment. We monitored eye movements while subjects searched for a color target on familiar or unfamiliar color backgrounds, in order to test for these performance changes and to explore whether they reflect changes in salience from adaptation vs. changes in search strategies or perceptual learning. The target was an ellipse of variable color presented at a random location on a dense background of ellipses. In one condition, the colors of the background varied along either the LvsM or SvsLM cardinal axes. Observers adapted by viewing a rapid succession of backgrounds drawn from one color axis, and then searched for a target on a background from the same or different color axis. Searches were monitored with a Cambridge Research Systems Video Eyetracker. Targets were located more quickly on the background axis that observers were pre-exposed to, confirming that this exposure can improve search efficiency for stimuli that differ from the background. However, eye movement patterns (e.g. fixation durations and saccade magnitudes) did not clearly differ across the two backgrounds, suggesting that how the novel and familiar backgrounds were sampled remained similar. In a second condition, we compared search on a nonselective color background drawn from a circle of hues at fixed contrast. Prior exposure to this background did not facilitate search compared to an achromatic adapting field, suggesting that subjects were not simply learning the specific colors defining the background distributions. Instead, results for both conditions are consistent with a selective adaptation effect that enhances the salience of novel stimuli by partially discounting the background.

  9. Getting satisfied with "satisfaction of search": How to measure errors during multiple-target visual search.

    Science.gov (United States)

    Biggs, Adam T

    2017-07-01

    Visual search studies are common in cognitive psychology, and the results generally focus upon accuracy, response times, or both. Most research has focused upon search scenarios where no more than 1 target will be present for any single trial. However, if multiple targets can be present on a single trial, it introduces an additional source of error because the found target can interfere with subsequent search performance. These errors have been studied thoroughly in radiology for decades, although their emphasis in cognitive psychology studies has been more recent. One particular issue with multiple-target search is that these subsequent search errors (i.e., specific errors which occur following a found target) are measured differently by different studies. There is currently no guidance as to which measurement method is best or what impact different measurement methods could have upon various results and conclusions. The current investigation provides two efforts to address these issues. First, the existing literature is reviewed to clarify the appropriate scenarios where subsequent search errors could be observed. Second, several different measurement methods are used with several existing datasets to contrast and compare how each method would have affected the results and conclusions of those studies. The evidence is then used to provide appropriate guidelines for measuring multiple-target search errors in future studies.

  10. Visual search attentional bias modification reduced social phobia in adolescents.

    Science.gov (United States)

    De Voogd, E L; Wiers, R W; Prins, P J M; Salemink, E

    2014-06-01

    An attentional bias for negative information plays an important role in the development and maintenance of (social) anxiety and depression, which are highly prevalent in adolescence. Attention Bias Modification (ABM) might be an interesting tool in the prevention of emotional disorders. The current study investigated whether visual search ABM might affect attentional bias and emotional functioning in adolescents. A visual search task was used as a training paradigm; participants (n = 16 adolescents, aged 13-16) had to repeatedly identify the only smiling face in a 4 × 4 matrix of negative emotional faces, while participants in the control condition (n = 16) were randomly allocated to one of three placebo training versions. An assessment version of the task was developed to directly test whether attentional bias changed due to the training. Self-reported anxiety and depressive symptoms and self-esteem were measured pre- and post-training. After two sessions of training, the ABM group showed a significant decrease in attentional bias for negative information and self-reported social phobia, while the control group did not. There were no effects of training on depressive mood or self-esteem. No correlation between attentional bias and social phobia was found, which raises questions about the validity of the attentional bias assessment task. Also, the small sample size precludes strong conclusions. Visual search ABM might be beneficial in changing attentional bias and social phobia in adolescents, but further research with larger sample sizes and longer follow-up is needed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Visual tracking method based on cuckoo search algorithm

    Science.gov (United States)

    Gao, Ming-Liang; Yin, Li-Ju; Zou, Guo-Feng; Li, Hai-Tao; Liu, Wei

    2015-07-01

    Cuckoo search (CS) is a new meta-heuristic optimization algorithm that is based on the obligate brood parasitic behavior of some cuckoo species in combination with the Lévy flight behavior of some birds and fruit flies. It has been found to be efficient in solving global optimization problems. An application of CS is presented to solve the visual tracking problem. The relationship between optimization and visual tracking is comparatively studied and the parameters' sensitivity and adjustment of CS in the tracking system are experimentally studied. To demonstrate the tracking ability of a CS-based tracker, a comparative study of tracking accuracy and speed of the CS-based tracker with six "state-of-art" trackers, namely, particle filter, meanshift, PSO, ensemble tracker, fragments tracker, and compressive tracker are presented. Comparative results show that the CS-based tracker outperforms the other trackers.

  12. Visual search performance in infants associates with later ASD diagnosis.

    Science.gov (United States)

    Cheung, C H M; Bedford, R; Johnson, M H; Charman, T; Gliga, T

    2016-09-30

    An enhanced ability to detect visual targets amongst distractors, known as visual search (VS), has often been documented in Autism Spectrum Disorders (ASD). Yet, it is unclear when this behaviour emerges in development and if it is specific to ASD. We followed up infants at high and low familial risk for ASD to investigate how early VS abilities links to later ASD diagnosis, the potential underlying mechanisms of this association and the specificity of superior VS to ASD. Clinical diagnosis of ASD as well as dimensional measures of ASD, attention-deficit/hyperactivity disorder (ADHD) and anxiety symptoms were ascertained at 3 years. At 9 and 15 months, but not at age 2 years, high-risk children who later met clinical criteria for ASD (HR-ASD) had better VS performance than those without later diagnosis and low-risk controls. Although HR-ASD children were also more attentive to the task at 9 months, this did not explain search performance. Superior VS specifically predicted 3 year-old ASD but not ADHD or anxiety symptoms. Our results demonstrate that atypical perception and core ASD symptoms of social interaction and communication are closely and selectively associated during early development, and suggest causal links between perceptual and social features of ASD. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  13. Greater sparing of visual search abilities in children after congenital rather than acquired focal brain damage.

    Science.gov (United States)

    Tinelli, Francesca; Guzzetta, Andrea; Bertini, Caterina; Ricci, Daniela; Mercuri, Eugenio; Ladavas, Elisabetta; Cioni, Giovanni

    2011-10-01

    Visual search refers to the capacity of an individual to find a target among simultaneously presented distracters and is based on visual abilities such as a fast visual processing and an accurate control of ballistic eye movements (saccades) that guide the fovea to the target location. In adults, visual field defects caused by brain damage are often associated with visual search disorders; in children, little is known about the effects of early brain lesions on visual search abilities. To test the presence of visual search defects and to investigate the role of cortical plasticity after early brain lesions, 29 children with congenital or acquired cerebral lesions, with and without visual field defects, underwent a visual search test battery. The children with acquired lesions and visual field defects had longer reaction times (RTs) in the contralesional visual field compared with the ipsilesional, whereas those with congenital lesions and visual field defects did not have differences in RTs between the contralateral and ipsilateral visual fields and had a visual search pattern similar to children without a visual field defect. These findings support the hypothesis of more effective mechanisms of functional compensation and reorganization of the visual system in children with very early brain lesions, as opposed to those with later damage.

  14. Searching for the right word: Hybrid visual and memory search for words.

    Science.gov (United States)

    Boettcher, Sage E P; Wolfe, Jeremy M

    2015-05-01

    In "hybrid search" (Wolfe Psychological Science, 23(7), 698-703, 2012), observers search through visual space for any of multiple targets held in memory. With photorealistic objects as the stimuli, response times (RTs) increase linearly with the visual set size and logarithmically with the memory set size, even when over 100 items are committed to memory. It is well-established that pictures of objects are particularly easy to memorize (Brady, Konkle, Alvarez, & Oliva Proceedings of the National Academy of Sciences, 105, 14325-14329, 2008). Would hybrid-search performance be similar if the targets were words or phrases, in which word order can be important, so that the processes of memorization might be different? In Experiment 1, observers memorized 2, 4, 8, or 16 words in four different blocks. After passing a memory test, confirming their memorization of the list, the observers searched for these words in visual displays containing two to 16 words. Replicating Wolfe (Psychological Science, 23(7), 698-703, 2012), the RTs increased linearly with the visual set size and logarithmically with the length of the word list. The word lists of Experiment 1 were random. In Experiment 2, words were drawn from phrases that observers reported knowing by heart (e.g., "London Bridge is falling down"). Observers were asked to provide four phrases, ranging in length from two words to no less than 20 words (range 21-86). All words longer than two characters from the phrase, constituted the target list. Distractor words were matched for length and frequency. Even with these strongly ordered lists, the results again replicated the curvilinear function of memory set size seen in hybrid search. One might expect to find serial position effects, perhaps reducing the RTs for the first (primacy) and/or the last (recency) members of a list (Atkinson & Shiffrin, 1968; Murdock Journal of Experimental Psychology, 64, 482-488, 1962). Surprisingly, we showed no reliable effects of word order

  15. Visual Search in ASD: Instructed versus Spontaneous Local and Global Processing

    Science.gov (United States)

    Van der Hallen, Ruth; Evers, Kris; Boets, Bart; Steyaert, Jean; Noens, Ilse; Wagemans, Johan

    2016-01-01

    Visual search has been used extensively to investigate differences in mid-level visual processing between individuals with ASD and TD individuals. The current study employed two visual search paradigms with Gaborized stimuli to assess the impact of task distractors (Experiment 1) and task instruction (Experiment 2) on local-global visual…

  16. Improvement in Visual Search with Practice : Mapping Learning-Related Changes in Neurocognitive Stages of Processing

    NARCIS (Netherlands)

    Clark, Kait; Appelbaum, L. Gregory; van den Berg, Berry; Mitroff, Stephen R.; Woldorff, Marty G.

    2015-01-01

    Practice can improve performance on visual search tasks; the neural mechanisms underlying such improvements, however, are not clear. Response time typically shortens with practice, but which components of the stimulus-response processing chain facilitate this behavioral change? Improved search

  17. Task Specificity and the Influence of Memory on Visual Search: Comment on Vo and Wolfe (2012)

    Science.gov (United States)

    Hollingworth, Andrew

    2012-01-01

    Recent results from Vo and Wolfe (2012b) suggest that the application of memory to visual search may be task specific: Previous experience searching for an object facilitated later search for that object, but object information acquired during a different task did not appear to transfer to search. The latter inference depended on evidence that a…

  18. Visual search patterns in semantic dementia show paradoxical facilitation of binding processes

    Science.gov (United States)

    Viskontas, Indre V.; Boxer, Adam L.; Fesenko, John; Matlin, Alisa; Heuer, Hilary W.; Mirsky, Jacob; Miller, Bruce L.

    2011-01-01

    While patients with Alzheimer’s disease (AD) show deficits in attention, manifested by inefficient performance on visual search, new visual talents can emerge in patients with frontotemporal lobar degeneration (FTLD), suggesting that, at least in some of the patients, visual attention is spared, if not enhanced. To investigate the underlying mechanisms for visual talent in FTLD (behavioral variant FTD [bvFTD] and semantic dementia [SD]) patients, we measured performance on a visual search paradigm that includes both feature and conjunction search, while simultaneously monitoring saccadic eye movements. AD patients were impaired relative to healthy controls (NC) and FTLD patients on both feature and conjunction search. BvFTD patients showed less accurate performance only on the conjunction search task, but slower response times than NC on all three tasks. In contrast, SD patients were as accurate as controls and had faster response times when faced with the largest number of distracters in the conjunction search task. Measurement of saccades during visual search showed that AD patients explored more of the image, whereas SD patients explored less of the image before making a decision as to whether the target was present. Performance on the conjunction search task positively correlated with gray matter volume in the superior parietal lobe, precuneus, middle frontal gyrus and superior temporal gyrus. These data suggest that despite the presence of extensive temporal lobe degeneration, visual talent in SD may be facilitated by more efficient visual search under distracting conditions due to enhanced function in the dorsal frontoparietal attention network. PMID:21215762

  19. Electrophysiological measurement of information flow during visual search.

    Science.gov (United States)

    Cosman, Joshua D; Arita, Jason T; Ianni, Julianna D; Woodman, Geoffrey F

    2016-04-01

    The temporal relationship between different stages of cognitive processing is long debated. This debate is ongoing, primarily because it is often difficult to measure the time course of multiple cognitive processes simultaneously. We employed a manipulation that allowed us to isolate ERP components related to perceptual processing, working memory, and response preparation, and then examined the temporal relationship between these components while observers performed a visual search task. We found that, when response speed and accuracy were equally stressed, our index of perceptual processing ended before both the transfer of information into working memory and response preparation began. However, when we stressed speed over accuracy, response preparation began before the completion of perceptual processing or transfer of information into working memory on trials with the fastest reaction times. These findings show that individuals can control the flow of information transmission between stages, either waiting for perceptual processing to be completed before preparing a response or configuring these stages to overlap in time. © 2015 Society for Psychophysiological Research.

  20. Does prism adaptation affect visual search in spatial neglect patients: A systematic review.

    Science.gov (United States)

    De Wit, Liselotte; Ten Brink, Antonia F; Visser-Meily, Johanna M A; Nijboer, Tanja C W

    2018-03-01

    Prism adaptation (PA) is a widely used intervention for (visuo-)spatial neglect. PA-induced improvements can be assessed by visual search tasks. It remains unclear which outcome measures are the most sensitive for the effects of PA in neglect. In this review, we aimed to evaluate PA effects on visual search measures. A systematic literature search was completed regarding PA intervention studies focusing on patients with neglect using visual search tasks. Information about study content and effectiveness was extracted. Out of 403 identified studies, 30 met the inclusion criteria. The quality of the studies was evaluated: Rankings were moderate-to-high for 7, and low for 23 studies. As feature search was only performed by five studies, low-to-moderate ranking, we were limited in drawing firm conclusions about the PA effect on feature search. All moderate-to-high-ranking studies investigated cancellation by measuring only omissions or hits. These studies found an overall improvement after PA. Measuring perseverations and total task duration provides more specific information about visual search. The two (low ranking) studies that measured this found an improvement after PA on perseverations and duration (while accuracy improved for one study and remained the same for the other). This review suggests there is an overall effect of PA on visual search, although complex visual search tasks and specific visual search measures are lacking. Suggestions for search measures that give insight in subcomponents of visual search are provided for future studies, such as perseverations, search path intersections, search consistency and using a speed-accuracy trade-off. © 2016 The British Psychological Society.

  1. Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search

    NARCIS (Netherlands)

    de Vries, I.E.J.; van Driel, J.; Olivers, C.N.L.

    2017-01-01

    Current models of visual search assume that search is guided by an active visual working memory representation of what we are currently looking for. This attentional template for currently relevant stimuli can be dissociated from accessory memory representations that are only needed prospectively,

  2. Person perception informs understanding of cognition during visual search.

    Science.gov (United States)

    Brennan, Allison A; Watson, Marcus R; Kingstone, Alan; Enns, James T

    2011-08-01

    Does person perception--the impressions we form from watching others--hold clues to the mental states of people engaged in cognitive tasks? We investigated this with a two-phase method: In Phase 1, participants searched on a computer screen (Experiment 1) or in an office (Experiment 2); in Phase 2, other participants rated the searchers' video-recorded behavior. The results showed that blind raters are sensitive to individual differences in search proficiency and search strategy, as well as to environmental factors affecting search difficulty. Also, different behaviors were linked to search success in each setting: Eye movement frequency predicted successful search on a computer screen; head movement frequency predicted search success in an office. In both settings, an active search strategy and positive emotional expressions were linked to search success. These data indicate that person perception informs cognition beyond the scope of performance measures, offering the potential for new measurements of cognition that are both rich and unobtrusive.

  3. The effect of search condition and advertising type on visual attention to Internet advertising.

    Science.gov (United States)

    Kim, Gho; Lee, Jang-Han

    2011-05-01

    This research was conducted to examine the level of consumers' visual attention to Internet advertising. It was predicted that consumers' search type would influence visual attention to advertising. Specifically, it was predicted that more attention to advertising would be attracted in the exploratory search condition than in the goal-directed search condition. It was also predicted that there would be a difference in visual attention depending on the advertisement type (advertising type: text vs. pictorial advertising). An eye tracker was used for measurement. Results revealed that search condition and advertising type influenced advertising effectiveness.

  4. The role of object categories in hybrid visual and memory search

    Science.gov (United States)

    Cunningham, Corbin A.; Wolfe, Jeremy M.

    2014-01-01

    In hybrid search, observers (Os) search for any of several possible targets in a visual display containing distracting items and, perhaps, a target. Wolfe (2012) found that responses times (RT) in such tasks increased linearly with increases in the number of items in the display. However, RT increased linearly with the log of the number of items in the memory set. In earlier work, all items in the memory set were unique instances (e.g. this apple in this pose). Typical real world tasks involve more broadly defined sets of stimuli (e.g. any “apple” or, perhaps, “fruit”). The present experiments show how sets or categories of targets are handled in joint visual and memory search. In Experiment 1, searching for a digit among letters was not like searching for targets from a 10-item memory set, though searching for targets from an N-item memory set of arbitrary alphanumeric characters was like searching for targets from an N-item memory set of arbitrary objects. In Experiment 2, Os searched for any instance of N sets or categories held in memory. This hybrid search was harder than search for specific objects. However, memory search remained logarithmic. Experiment 3 illustrates the interaction of visual guidance and memory search when a subset of visual stimuli are drawn from a target category. Furthermore, we outline a conceptual model, supported by our results, defining the core components that would be necessary to support such categorical hybrid searches. PMID:24661054

  5. Overcoming hurdles in translating visual search research between the lab and the field.

    Science.gov (United States)

    Clark, Kait; Cain, Matthew S; Adamo, Stephen H; Mitroff, Stephen R

    2012-01-01

    Research in visual search can be vital to improving performance in careers such as radiology and airport security screening. In these applied, or "field," searches, accuracy is critical, and misses are potentially fatal; however, despite the importance of performing optimally, radiological and airport security searches are nevertheless flawed. Extensive basic research in visual search has revealed cognitive mechanisms responsible for successful visual search as well as a variety of factors that tend to inhibit or improve performance. Ideally, the knowledge gained from such laboratory-based research could be directly applied to field searches, but several obstacles stand in the way of straightforward translation; the tightly controlled visual searches performed in the lab can be drastically different from field searches. For example, they can differ in terms of the nature of the stimuli, the environment in which the search is taking place, and the experience and characteristics of the searchers themselves. The goal of this chapter is to discuss these differences and how they can present hurdles to translating lab-based research to field-based searches. Specifically, most search tasks in the lab entail searching for only one target per trial, and the targets occur relatively frequently, but field searches may contain an unknown and unlimited number of targets, and the occurrence of targets can be rare. Additionally, participants in lab-based search experiments often perform under neutral conditions and have no formal training or experience in search tasks; conversely, career searchers may be influenced by the motivation to perform well or anxiety about missing a target, and they have undergone formal training and accumulated significant experience searching. This chapter discusses recent work that has investigated the impacts of these differences to determine how each factor can influence search performance. Knowledge gained from the scientific exploration of search

  6. How Visual Search Relates to Visual Diagnostic Performance: A Narrative Systematic Review of Eye-Tracking Research in Radiology

    Science.gov (United States)

    van der Gijp, A.; Ravesloot, C. J.; Jarodzka, H.; van der Schaaf, M. F.; van der Schaaf, I. C.; van Schaik, J. P.; ten Cate, Th. J.

    2017-01-01

    Eye tracking research has been conducted for decades to gain understanding of visual diagnosis such as in radiology. For educational purposes, it is important to identify visual search patterns that are related to high perceptual performance and to identify effective teaching strategies. This review of eye-tracking literature in the radiology…

  7. How visual search relates to visual diagnostic performance : a narrative systematic review of eye-tracking research in radiology

    NARCIS (Netherlands)

    van der Gijp, A; Ravesloot, C J; Jarodzka, H; van der Schaaf, M F|info:eu-repo/dai/nl/073361917; van der Schaaf, I C; van Schaik, Jan P J; Ten Cate, Th J

    Eye tracking research has been conducted for decades to gain understanding of visual diagnosis such as in radiology. For educational purposes, it is important to identify visual search patterns that are related to high perceptual performance and to identify effective teaching strategies. This review

  8. Interactive Visualization and Navigation of Web Search Results Revealing Community Structures and Bridges

    OpenAIRE

    Sallaberry, Arnaud; Zaidi, Faraz; Pich, C.; Melançon, Guy

    2010-01-01

    International audience; With the information overload on the Internet, organization and visualization of web search results so as to facilitate faster access to information is a necessity. The classical methods present search results as an ordered list of web pages ranked in terms of relevance to the searched topic. Users thus have to scan text snippets or navigate through various pages before finding the required information. In this paper we present an interactive visualization system for c...

  9. Do People Take Stimulus Correlations into Account in Visual Search (Open Source)

    Science.gov (United States)

    2016-03-10

    contribute to bridging the gap between artificial and natural visual search tasks. Introduction Visual target detection in displays consisting of multiple...on an invisible circle centered at the fixation cross, with a radius of 3.2 degrees of visual angle. On each trial, the first stimulus was placed at

  10. Looking sharp: Becoming a search template boosts precision and stability in visual working memory.

    Science.gov (United States)

    Rajsic, Jason; Ouslis, Natasha E; Wilson, Daryl E; Pratt, Jay

    2017-08-01

    Visual working memory (VWM) plays a central role in visual cognition, and current work suggests that there is a special state in VWM for items that are the goal of visual searches. However, whether the quality of memory for target templates differs from memory for other items in VWM is currently unknown. In this study, we measured the precision and stability of memory for search templates and accessory items to determine whether search templates receive representational priority in VWM. Memory for search templates exhibited increased precision and probability of recall, whereas accessory items were remembered less often. Additionally, while memory for Templates showed benefits when instances of the Template appeared in search, this benefit was not consistently observed for Accessory items when they appeared in search. Our results show that becoming a search template can substantially affect the quality of a representation in VWM.

  11. High or Low Target Prevalence Increases the Dual-Target Cost in Visual Search

    Science.gov (United States)

    Menneer, Tamaryn; Donnelly, Nick; Godwin, Hayward J.; Cave, Kyle R.

    2010-01-01

    Previous studies have demonstrated a dual-target cost in visual search. In the current study, the relationship between search for one and search for two targets was investigated to examine the effects of target prevalence and practice. Color-shape conjunction stimuli were used with response time, accuracy and signal detection measures. Performance…

  12. Interactions of visual odometry and landmark guidance during food search in honeybees

    NARCIS (Netherlands)

    Vladusich, T; Hemmi, JM; Srinivasan, MV; Zeil, J

    2005-01-01

    How do honeybees use visual odometry and goal-defining landmarks to guide food search? In one experiment, bees were trained to forage in an optic-flow-rich tunnel with a landmark positioned directly above the feeder. Subsequent food-search tests indicated that bees searched much more accurately when

  13. Choosing colors for map display icons using models of visual search.

    Science.gov (United States)

    Shive, Joshua; Francis, Gregory

    2013-04-01

    We show how to choose colors for icons on maps to minimize search time using predictions of a model of visual search. The model analyzes digital images of a search target (an icon on a map) and a search display (the map containing the icon) and predicts search time as a function of target-distractor color distinctiveness and target eccentricity. We parameterized the model using data from a visual search task and performed a series of optimization tasks to test the model's ability to choose colors for icons to minimize search time across icons. Map display designs made by this procedure were tested experimentally. In a follow-up experiment, we examined the model's flexibility to assign colors in novel search situations. The model fits human performance, performs well on the optimization tasks, and can choose colors for icons on maps with novel stimuli to minimize search time without requiring additional model parameter fitting. Models of visual search can suggest color choices that produce search time reductions for display icons. Designers should consider constructing visual search models as a low-cost method of evaluating color assignments.

  14. Acute effects of caffeine on selective attention and visual search processes

    NARCIS (Netherlands)

    Lorist, M.M.; Snel, J.; Kok, A; Mulder, G.

    The influence of a single dose of caffeine was evaluated in focused and divided attention conditions of a visual selective search task in which subjects had to perform controlled search processes to locate a target item. Search processes were manipulated by varying display load. A dose of 3 mg/kg

  15. Smart Images Search based on Visual Features Fusion

    International Nuclear Information System (INIS)

    Saad, M.H.

    2013-01-01

    Image search engines attempt to give fast and accurate access to the wide range of the huge amount images available on the Internet. There have been a number of efforts to build search engines based on the image content to enhance search results. Content-Based Image Retrieval (CBIR) systems have achieved a great interest since multimedia files, such as images and videos, have dramatically entered our lives throughout the last decade. CBIR allows automatically extracting target images according to objective visual contents of the image itself, for example its shapes, colors and textures to provide more accurate ranking of the results. The recent approaches of CBIR differ in terms of which image features are extracted to be used as image descriptors for matching process. This thesis proposes improvements of the efficiency and accuracy of CBIR systems by integrating different types of image features. This framework addresses efficient retrieval of images in large image collections. A comparative study between recent CBIR techniques is provided. According to this study; image features need to be integrated to provide more accurate description of image content and better image retrieval accuracy. In this context, this thesis presents new image retrieval approaches that provide more accurate retrieval accuracy than previous approaches. The first proposed image retrieval system uses color, texture and shape descriptors to form the global features vector. This approach integrates the yc b c r color histogram as a color descriptor, the modified Fourier descriptor as a shape descriptor and modified Edge Histogram as a texture descriptor in order to enhance the retrieval results. The second proposed approach integrates the global features vector, which is used in the first approach, with the SURF salient point technique as local feature. The nearest neighbor matching algorithm with a proposed similarity measure is applied to determine the final image rank. The second approach

  16. Effects of absolute luminance and luminance contrast on visual search in low mesopic environments.

    Science.gov (United States)

    Hunter, Mathew; Godde, Ben; Olk, Bettina

    2018-03-26

    Diverse adaptive visual processing mechanisms allow us to complete visual search tasks in a wide visual photopic range (>0.6 cd/m 2 ). Whether search strategies or mechanisms known from this range extend below, in the mesopic and scotopic luminance spectra (search in more complex-feature and conjunction-search paradigms. The results verify the previously reported deficiency windows defined by an interaction of base luminance and luminance contrast for more complex visual-search tasks. Based on significant regression analyses, a more precise definition of the magnitude of contribution of different contrast parameters. Characterized feature search patterns had approximately a 2.5:1 ratio of contribution from the Michelson contrast property relative to Weber contrast, whereas the ratio was approximately 1:1 in a serial-search condition. The results implicate near-complete magnocellular isolation in a visual-search paradigm that has yet to be demonstrated. Our analyses provide a new method of characterizing visual search and the first insight in its underlying mechanisms in luminance environments in the low mesopic and scotopic spectra.

  17. Episodic retrieval and feature facilitation in intertrial priming of visual search

    DEFF Research Database (Denmark)

    Asgeirsson, Arni Gunnar; Kristjánsson, Árni

    2011-01-01

    Abstract Huang, Holcombe, and Pashler (Memory & Cognition, 32, 12–20, 2004) found that priming from repetition of different features of a target in a visual search task resulted in significant response time (RT) reductions when both target brightness and size were repeated. But when only one feat...... features occurs independently. The results support two-stage (or multistage) accounts of priming in visual search.......Abstract Huang, Holcombe, and Pashler (Memory & Cognition, 32, 12–20, 2004) found that priming from repetition of different features of a target in a visual search task resulted in significant response time (RT) reductions when both target brightness and size were repeated. But when only one...... feature was repeated and the other changed, RTs were longer than when neither feature was repeated. From this, they argued that priming in visual search reflected episodic retrieval of memory traces, rather than facilitation of repeated features. We tested different varia- tions of the search task...

  18. A survey on visual information search behavior and requirements of radiologists.

    Science.gov (United States)

    Markonis, D; Holzer, M; Dungs, S; Vargas, A; Langs, G; Kriewel, S; Müller, H

    2012-01-01

    The main objective of this study is to learn more on the image use and search requirements of radiologists. These requirements will then be taken into account to develop a new search system for images and associated meta data search in the Khresmoi project. Observations of the radiology workflow, case discussions and a literature review were performed to construct a survey form that was given online and in paper form to radiologists. Eye tracking was performed on a radiology viewing station to analyze typical tasks and to complement the survey. In total 34 radiologists answered the survey online or on paper. Image search was mentioned as a frequent and common task, particularly for finding cases of interest for differential diagnosis. Sources of information besides the Internet are books and discussions with colleagues. Search for images is unsuccessful in around 25% of the cases, stopping the search after around 10 minutes. The most common reason for failure is that target images are considered rare. Important additions for search requested in the survey are filtering by pathology and modality, as well as search for visually similar images and cases. Few radiologists are familiar with visual retrieval but they desire the option to upload images for searching similar ones. Image search is common in radiology but few radiologists are fully aware of visual information retrieval. Taking into account the many unsuccessful searches and time spent for this, a good image search could improve the situation and help in clinical practice.

  19. Scanners and drillers: Characterizing expert visual search through volumetric images

    Science.gov (United States)

    Drew, Trafton; Vo, Melissa Le-Hoa; Olwal, Alex; Jacobson, Francine; Seltzer, Steven E.; Wolfe, Jeremy M.

    2013-01-01

    Modern imaging methods like computed tomography (CT) generate 3-D volumes of image data. How do radiologists search through such images? Are certain strategies more efficient? Although there is a large literature devoted to understanding search in 2-D, relatively little is known about search in volumetric space. In recent years, with the ever-increasing popularity of volumetric medical imaging, this question has taken on increased importance as we try to understand, and ultimately reduce, errors in diagnostic radiology. In the current study, we asked 24 radiologists to search chest CTs for lung nodules that could indicate lung cancer. To search, radiologists scrolled up and down through a “stack” of 2-D chest CT “slices.” At each moment, we tracked eye movements in the 2-D image plane and coregistered eye position with the current slice. We used these data to create a 3-D representation of the eye movements through the image volume. Radiologists tended to follow one of two dominant search strategies: “drilling” and “scanning.” Drillers restrict eye movements to a small region of the lung while quickly scrolling through depth. Scanners move more slowly through depth and search an entire level of the lung before moving on to the next level in depth. Driller performance was superior to the scanners on a variety of metrics, including lung nodule detection rate, percentage of the lung covered, and the percentage of search errors where a nodule was never fixated. PMID:23922445

  20. Attentional control during visual search: The effect of irrelevant singletons

    NARCIS (Netherlands)

    Theeuwes, J.; Burger, R.

    1998-01-01

    Four experiments investigated whether a highly salient color singleton can be ignored during serial search. Observers searched for a target letter among nontarget letters and were instructed to ignore an irrelevant, highly salient color singleton that was either compatible or incompatible with the

  1. Journal of Health and Visual Sciences: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  2. Investigating the role of visual and auditory search in reading and developmental dyslexia

    Directory of Open Access Journals (Sweden)

    Marie eLallier

    2013-09-01

    Full Text Available It has been suggested that auditory and visual sequential processing deficits contribute to phonological disorders in developmental dyslexia. As an alternative explanation to a phonological deficit as the proximal cause for reading disorders, the visual attention span hypothesis (VA Span suggests that difficulties in processing visual elements simultaneously lead to dyslexia, regardless of the presence of a phonological disorder. In this study, we assessed whether deficits in processing simultaneously displayed visual or auditory elements is linked to dyslexia associated with a VA Span impairment. Sixteen children with developmental dyslexia and 16 age-matched skilled readers were assessed on visual and auditory search tasks. Participants were asked to detect a target presented simultaneously with 3, 9 or 15 distracters. In the visual modality, target detection was slower in the dyslexic children than in the control group on a serial search condition only: the intercepts (but not the slopes of the search functions were higher in the dyslexic group than in the control group. In the auditory modality, although no group difference was observed, search performance was influenced by the number of distracters in the control group only. Within the dyslexic group, not only poor visual search (high reaction times and intercepts but also low auditory search performance (d´ strongly correlated with poor irregular word reading accuracy. Moreover, both visual and auditory search performance was associated with the VA Span abilities of dyslexic participants but not with their phonological skills. The present data suggests that some visual mechanisms engaged in serial search contribute to reading and orthographic knowledge via VA Span skills regardless of phonological skills. The present results further open the question of the role of auditory simultaneous processing in reading as well as its link with VA Span skills.

  3. Visual search in scenes involves selective and non-selective pathways

    Science.gov (United States)

    Wolfe, Jeremy M; Vo, Melissa L-H; Evans, Karla K; Greene, Michelle R

    2010-01-01

    How do we find objects in scenes? For decades, visual search models have been built on experiments in which observers search for targets, presented among distractor items, isolated and randomly arranged on blank backgrounds. Are these models relevant to search in continuous scenes? This paper argues that the mechanisms that govern artificial, laboratory search tasks do play a role in visual search in scenes. However, scene-based information is used to guide search in ways that had no place in earlier models. Search in scenes may be best explained by a dual-path model: A “selective” path in which candidate objects must be individually selected for recognition and a “non-selective” path in which information can be extracted from global / statistical information. PMID:21227734

  4. Cardiac and Respiratory Responses During Visual Search in Nonretarded Children and Retarded Adolescents

    Science.gov (United States)

    Porges, Stephen W.; Humphrey, Mary M.

    1977-01-01

    The relationship between physiological response patterns and mental competence was investigated by evaluating heart rate and respiratory responses during a sustained visual-search task in 29 nonretarded grade school children and 16 retarded adolescents. (Author)

  5. Computer-Assisted Visual Search/Decision Aids as a Training Tool for Mammography

    National Research Council Canada - National Science Library

    Nodine, Calvin

    1999-01-01

    The primary goal of the project is to develop a computer-assisted visual search (CAVS) mammography training tool that will improve the perceptual and cognitive skills of trainees leading to mammographic expertise...

  6. Computer-Assisted Visual Search/Decision Aids as a Training Tool for Mammography

    National Research Council Canada - National Science Library

    Nodine, Calvin

    2000-01-01

    The primary goal of the project is to develop a computer-assisted visual search (CAVS) mammography training tool that will improve the perceptual and cognitive skills of trainees leading to mammographic expertise...

  7. Computer-Assisted Visual Search/Decision Aids as a Training Tool for Mammography

    National Research Council Canada - National Science Library

    Nodine, Calvin

    1998-01-01

    The primary goal of the project is to develop a computer-assisted visual search (CAVS) mammography training tool that will improve the perceptual and cognitive skills of trainees leading to mammographic expertise...

  8. Computational assessment of visual search strategies in volumetric medical images.

    Science.gov (United States)

    Wen, Gezheng; Aizenman, Avigael; Drew, Trafton; Wolfe, Jeremy M; Haygood, Tamara Miner; Markey, Mia K

    2016-01-01

    When searching through volumetric images [e.g., computed tomography (CT)], radiologists appear to use two different search strategies: "drilling" (restrict eye movements to a small region of the image while quickly scrolling through slices), or "scanning" (search over large areas at a given depth before moving on to the next slice). To computationally identify the type of image information that is used in these two strategies, 23 naïve observers were instructed with either "drilling" or "scanning" when searching for target T's in 20 volumes of faux lung CTs. We computed saliency maps using both classical two-dimensional (2-D) saliency, and a three-dimensional (3-D) dynamic saliency that captures the characteristics of scrolling through slices. Comparing observers' gaze distributions with the saliency maps showed that search strategy alters the type of saliency that attracts fixations. Drillers' fixations aligned better with dynamic saliency and scanners with 2-D saliency. The computed saliency was greater for detected targets than for missed targets. Similar results were observed in data from 19 radiologists who searched five stacks of clinical chest CTs for lung nodules. Dynamic saliency may be superior to the 2-D saliency for detecting targets embedded in volumetric images, and thus "drilling" may be more efficient than "scanning."

  9. The role of object categories in hybrid visual and memory search.

    Science.gov (United States)

    Cunningham, Corbin A; Wolfe, Jeremy M

    2014-08-01

    In hybrid search, observers search for any of several possible targets in a visual display containing distracting items and, perhaps, a target. Wolfe (2012) found that response times (RTs) in such tasks increased linearly with increases in the number of items in the display. However, RT increased linearly with the log of the number of items in the memory set. In earlier work, all items in the memory set were unique instances (e.g., this apple in this pose). Typical real-world tasks involve more broadly defined sets of stimuli (e.g., any "apple" or, perhaps, "fruit"). The present experiments show how sets or categories of targets are handled in joint visual and memory search. In Experiment 1, searching for a digit among letters was not like searching for targets from a 10-item memory set, though searching for targets from an N-item memory set of arbitrary alphanumeric characters was like searching for targets from an N-item memory set of arbitrary objects. In Experiment 2, observers searched for any instance of N sets or categories held in memory. This hybrid search was harder than search for specific objects. However, memory search remained logarithmic. Experiment 3 illustrates the interaction of visual guidance and memory search when a subset of visual stimuli are drawn from a target category. Furthermore, we outline a conceptual model, supported by our results, defining the core components that would be necessary to support such categorical hybrid searches. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  10. The price of information: Increased inspection costs reduce the confirmation bias in visual search.

    Science.gov (United States)

    Rajsic, Jason; Wilson, Daryl E; Pratt, Jay

    2018-04-01

    In visual search, there is a confirmation bias such that attention is biased towards stimuli that match a target template, which has been attributed to covert costs of updating the templates that guide search [Rajsic, Wilson, & Pratt, 2015. Confirmation bias in visual search. Journal of Experimental Psychology: Human Perception and Performance. Advance online publication. doi:10.1037/xhp0000090]. In order to provide direct evidence for this speculation, the present study increased the cost of inspections in search by using gaze- and mouse-contingent searches, which restrict the manner in which information in search displays can be accrued, and incur additional motor costs (in the case of mouse-contingent searches). In a fourth experiment, we rhythmically mask elements in the search display to induce temporal inspection costs. Our results indicated that confirmation bias is indeed attenuated when inspection costs are increased. We conclude that confirmation bias results from the low-cost strategy of matching information to a single, concrete visual template, and that more sophisticated guidance strategies will be used when sufficiently beneficial. This demonstrates that search guidance itself comes at a cost, and that the form of guidance adopted in a given search depends on a comparison between guidance costs and the expected benefits of their implementation.

  11. Influence of social presence on eye movements in visual search tasks.

    Science.gov (United States)

    Liu, Na; Yu, Ruifeng

    2017-12-01

    This study employed an eye-tracking technique to investigate the influence of social presence on eye movements in visual search tasks. A total of 20 male subjects performed visual search tasks in a 2 (target presence: present vs. absent) × 2 (task complexity: complex vs. simple) × 2 (social presence: alone vs. a human audience) within-subject experiment. Results indicated that the presence of an audience could evoke a social facilitation effect on response time in visual search tasks. Compared with working alone, the participants made fewer and shorter fixations, larger saccades and shorter scan path in simple search tasks and more and longer fixations, smaller saccades and longer scan path in complex search tasks when working with an audience. The saccade velocity and pupil diameter in the audience-present condition were larger than those in the working-alone condition. No significant change in target fixation number was observed between two social presence conditions. Practitioner Summary: This study employed an eye-tracking technique to examine the influence of social presence on eye movements in visual search tasks. Results clarified the variation mechanism and characteristics of oculomotor scanning induced by social presence in visual search.

  12. Spatial partitions systematize visual search and enhance target memory.

    Science.gov (United States)

    Solman, Grayden J F; Kingstone, Alan

    2017-02-01

    Humans are remarkably capable of finding desired objects in the world, despite the scale and complexity of naturalistic environments. Broadly, this ability is supported by an interplay between exploratory search and guidance from episodic memory for previously observed target locations. Here we examined how the environment itself may influence this interplay. In particular, we examined how partitions in the environment-like buildings, rooms, and furniture-can impact memory during repeated search. We report that the presence of partitions in a display, independent of item configuration, reliably improves episodic memory for item locations. Repeated search through partitioned displays was faster overall and was characterized by more rapid ballistic orienting in later repetitions. Explicit recall was also both faster and more accurate when displays were partitioned. Finally, we found that search paths were more regular and systematic when displays were partitioned. Given the ubiquity of partitions in real-world environments, these results provide important insights into the mechanisms of naturalistic search and its relation to memory.

  13. Implicit short- and long-term memory direct our gaze in visual search

    NARCIS (Netherlands)

    Kruijne, Wouter; Meeter, Martijn

    2016-01-01

    Visual attention is strongly affected by the past: both by recent experience and by long-term regularities in the environment that are encoded in and retrieved from memory. In visual search, intertrial repetition of targets causes speeded response times (short-term priming). Similarly, targets that

  14. Recognition of Facially Expressed Emotions and Visual Search Strategies in Adults with Asperger Syndrome

    Science.gov (United States)

    Falkmer, Marita; Bjallmark, Anna; Larsson, Matilda; Falkmer, Torbjorn

    2011-01-01

    Can the disadvantages persons with Asperger syndrome frequently experience with reading facially expressed emotions be attributed to a different visual perception, affecting their scanning patterns? Visual search strategies, particularly regarding the importance of information from the eye area, and the ability to recognise facially expressed…

  15. Don't admit defeat : A new dawn for the item in visual search

    NARCIS (Netherlands)

    Van der Stigchel, Stefan; Mathot, Sebastiaan

    2017-01-01

    Even though we lack a precise definition of "item," it is clear that people do parse their visual environment into objects (the real-world equivalent of items). We will review evidence that items are essential in visual search, and argue that computer vision - especially deep learning - may offer a

  16. Toddlers' language-mediated visual search: they need not have the words for it

    NARCIS (Netherlands)

    Johnson, E.K.; McQueen, J.M.; Hüttig, F.

    2011-01-01

    Eye movements made by listeners during language-mediated visual search reveal a strong link between visual processing and conceptual processing. For example, upon hearing the word for a missing referent with a characteristic colour (e.g., “strawberry”), listeners tend to fixate a colour-matched

  17. The influence of artificial scotomas on eye movements during visual search

    NARCIS (Netherlands)

    Cornelissen, FW; Bruin, KJ; Kooijman, AC

    Purpose. Fixation durations are normally adapted to the difficulty of the foveal analysis task. We examine to what extent artificial central and peripheral visual field defects interfere with this adaptation process. Methods. Subjects performed a visual search task while their eye movements were

  18. The Effects of Presentation Method and Information Density on Visual Search Ability and Working Memory Load

    Science.gov (United States)

    Chang, Ting-Wen; Kinshuk; Chen, Nian-Shing; Yu, Pao-Ta

    2012-01-01

    This study investigates the effects of successive and simultaneous information presentation methods on learner's visual search ability and working memory load for different information densities. Since the processing of information in the brain depends on the capacity of visual short-term memory (VSTM), the limited information processing capacity…

  19. The role of space and time in object-based visual search

    NARCIS (Netherlands)

    Schreij, D.B.B.; Olivers, C.N.L.

    2013-01-01

    Recently we have provided evidence that observers more readily select a target from a visual search display if the motion trajectory of the display object suggests that the observer has dealt with it before. Here we test the prediction that this object-based memory effect on search breaks down if

  20. Contextual Cueing in Multiconjunction Visual Search Is Dependent on Color- and Configuration-Based Intertrial Contingencies

    Science.gov (United States)

    Geyer, Thomas; Shi, Zhuanghua; Muller, Hermann J.

    2010-01-01

    Three experiments examined memory-based guidance of visual search using a modified version of the contextual-cueing paradigm (Jiang & Chun, 2001). The target, if present, was a conjunction of color and orientation, with target (and distractor) features randomly varying across trials (multiconjunction search). Under these conditions, reaction times…

  1. Central and Peripheral Vision Loss Differentially Affects Contextual Cueing in Visual Search

    Science.gov (United States)

    Geringswald, Franziska; Pollmann, Stefan

    2015-01-01

    Visual search for targets in repeated displays is more efficient than search for the same targets in random distractor layouts. Previous work has shown that this contextual cueing is severely impaired under central vision loss. Here, we investigated whether central vision loss, simulated with gaze-contingent displays, prevents the incidental…

  2. Long-term priming of visual search prevails against the passage of time and counteracting instructions

    NARCIS (Netherlands)

    Kruijne, W.; Meeter, M.

    2016-01-01

    Studies on intertrial priming have shown that in visual search experiments, the preceding trial automatically affects search performance: facilitating it when the target features repeat and giving rise to switch costs when they change-so-called (short-term) intertrial priming. These effects also

  3. Long-Term Priming of Visual Search Prevails against the Passage of Time and Counteracting Instructions

    Science.gov (United States)

    Kruijne, Wouter; Meeter, Martijn

    2016-01-01

    Studies on "intertrial priming" have shown that in visual search experiments, the preceding trial automatically affects search performance: facilitating it when the target features repeat and giving rise to switch costs when they change--so-called (short-term) intertrial priming. These effects also occur at longer time scales: When 1 of…

  4. Shape representation modulating the effect of motion on visual search performance.

    Science.gov (United States)

    Yang, Lindong; Yu, Ruifeng; Lin, Xuelian; Liu, Na

    2017-11-02

    The effect of motion on visual search has been extensively investigated, but that of uniform linear motion of display on search performance for tasks with different target-distractor shape representations has been rarely explored. The present study conducted three visual search experiments. In Experiments 1 and 2, participants finished two search tasks that differed in target-distractor shape representations under static and dynamic conditions. Two tasks with clear and blurred stimuli were performed in Experiment 3. The experiments revealed that target-distractor shape representation modulated the effect of motion on visual search performance. For tasks with low target-distractor shape similarity, motion negatively affected search performance, which was consistent with previous studies. However, for tasks with high target-distractor shape similarity, if the target differed from distractors in that a gap with a linear contour was added to the target, and the corresponding part of distractors had a curved contour, motion positively influenced search performance. Motion blur contributed to the performance enhancement under dynamic conditions. The findings are useful for understanding the influence of target-distractor shape representation on dynamic visual search performance when display had uniform linear motion.

  5. Effect of marihuana and alcohol on visual search performance

    Science.gov (United States)

    1976-10-01

    Two experiments were performed to determine the effects of alcohol and marihuana on visual scanning patterns in a simulated driving situation. In the first experiment 27 male heavy drinkers were divided into 3 groups of 9, defined by three blood alco...

  6. Optimization of interactive visual-similarity-based search

    NARCIS (Netherlands)

    Nguyen, G.P.; Worring, M.

    2008-01-01

    At one end of the spectrum, research in interactive content-based retrieval concentrates on machine learning methods for effective use of relevance feedback. On the other end, the information visualization community focuses on effective methods for conveying information to the user. What is lacking

  7. Peripheral Vision of Youths with Low Vision: Motion Perception, Crowding, and Visual Search

    Science.gov (United States)

    Tadin, Duje; Nyquist, Jeffrey B.; Lusk, Kelly E.; Corn, Anne L.; Lappin, Joseph S.

    2012-01-01

    Purpose. Effects of low vision on peripheral visual function are poorly understood, especially in children whose visual skills are still developing. The aim of this study was to measure both central and peripheral visual functions in youths with typical and low vision. Of specific interest was the extent to which measures of foveal function predict performance of peripheral tasks. Methods. We assessed central and peripheral visual functions in youths with typical vision (n = 7, ages 10–17) and low vision (n = 24, ages 9–18). Experimental measures used both static and moving stimuli and included visual crowding, visual search, motion acuity, motion direction discrimination, and multitarget motion comparison. Results. In most tasks, visual function was impaired in youths with low vision. Substantial differences, however, were found both between participant groups and, importantly, across different tasks within participant groups. Foveal visual acuity was a modest predictor of peripheral form vision and motion sensitivity in either the central or peripheral field. Despite exhibiting normal motion discriminations in fovea, motion sensitivity of youths with low vision deteriorated in the periphery. This contrasted with typically sighted participants, who showed improved motion sensitivity with increasing eccentricity. Visual search was greatly impaired in youths with low vision. Conclusions. Our results reveal a complex pattern of visual deficits in peripheral vision and indicate a significant role of attentional mechanisms in observed impairments. These deficits were not adequately captured by measures of foveal function, arguing for the importance of independently assessing peripheral visual function. PMID:22836766

  8. Mobile Visual Search Based on Histogram Matching and Zone Weight Learning

    Science.gov (United States)

    Zhu, Chuang; Tao, Li; Yang, Fan; Lu, Tao; Jia, Huizhu; Xie, Xiaodong

    2018-01-01

    In this paper, we propose a novel image retrieval algorithm for mobile visual search. At first, a short visual codebook is generated based on the descriptor database to represent the statistical information of the dataset. Then, an accurate local descriptor similarity score is computed by merging the tf-idf weighted histogram matching and the weighting strategy in compact descriptors for visual search (CDVS). At last, both the global descriptor matching score and the local descriptor similarity score are summed up to rerank the retrieval results according to the learned zone weights. The results show that the proposed approach outperforms the state-of-the-art image retrieval method in CDVS.

  9. Multisensory brand search: How the meaning of sounds guides consumers' visual attention.

    Science.gov (United States)

    Knoeferle, Klemens M; Knoeferle, Pia; Velasco, Carlos; Spence, Charles

    2016-06-01

    Building on models of crossmodal attention, the present research proposes that brand search is inherently multisensory, in that the consumers' visual search for a specific brand can be facilitated by semantically related stimuli that are presented in another sensory modality. A series of 5 experiments demonstrates that the presentation of spatially nonpredictive auditory stimuli associated with products (e.g., usage sounds or product-related jingles) can crossmodally facilitate consumers' visual search for, and selection of, products. Eye-tracking data (Experiment 2) revealed that the crossmodal effect of auditory cues on visual search manifested itself not only in RTs, but also in the earliest stages of visual attentional processing, thus suggesting that the semantic information embedded within sounds can modulate the perceptual saliency of the target products' visual representations. Crossmodal facilitation was even observed for newly learnt associations between unfamiliar brands and sonic logos, implicating multisensory short-term learning in establishing audiovisual semantic associations. The facilitation effect was stronger when searching complex rather than simple visual displays, thus suggesting a modulatory role of perceptual load. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  10. Rapid resumption of interrupted visual search. New insights on the interaction between vision and memory.

    Science.gov (United States)

    Lleras, Alejandro; Rensink, Ronald A; Enns, James T

    2005-09-01

    A modified visual search task demonstrates that humans are very good at resuming a search after it has been momentarily interrupted. This is shown by exceptionally rapid response time to a display that reappears after a brief interruption, even when an entirely different visual display is seen during the interruption and two different visual searches are performed simultaneously. This rapid resumption depends on the stability of the visual scene and is not due to display or response anticipations. These results are consistent with the existence of an iterative hypothesis-testing mechanism that compares information stored in short-term memory (the perceptual hypothesis) with information about the display (the sensory pattern). In this view, rapid resumption occurs because a hypothesis based on a previous glance of the scene can be tested very rapidly in a subsequent glance, given that the initial hypothesis-generation step has already been performed.

  11. Climate and colored walls: in search of visual comfort

    Science.gov (United States)

    Arrarte-Grau, Malvina

    2002-06-01

    The quality of natural light, the landscape surrounds and the techniques of construction are important factors in the selection of architectural colors. Observation of exterior walls in differentiated climates allows the recognition of particularities in the use of color which satisfy the need for visual comfort. At a distance of 2000 kilometers along the coast of Peru, Lima and Mancora at 12° and 4° respectively, are well defined for their climatic characteristics: in Mancora sunlight causes high reflection, in Lima overcast sky and high humidity cause glare. The study of building color effects at these locations serves to illustrate that color values may be controlled in order to achieve visual comfort and contribute to color identity.

  12. Playing shooter and driving videogames improves top-down guidance in visual search.

    Science.gov (United States)

    Wu, Sijing; Spence, Ian

    2013-05-01

    Playing action videogames is known to improve visual spatial attention and related skills. Here, we showed that playing action videogames also improves classic visual search, as well as the ability to locate targets in a dual search that mimics certain aspects of an action videogame. In Experiment 1A, first-person shooter (FPS) videogame players were faster than nonplayers in both feature search and conjunction search, and in Experiment 1B, they were faster and more accurate in a peripheral search and identification task while simultaneously performing a central search. In Experiment 2, we showed that 10 h of play could improve the performance of nonplayers on each of these tasks. Three different genres of videogames were used for training: two action games and a 3-D puzzle game. Participants who played an action game (either an FPS or a driving game) achieved greater gains on all search tasks than did those who trained using the puzzle game. Feature searches were faster after playing an action videogame, suggesting that players developed a better target template to guide search in a top-down manner. The results of the dual search suggest that, in addition to enhancing the ability to divide attention, playing an action game improves the top-down guidance of attention to possible target locations. The results have practical implications for the development of training tools to improve perceptual and cognitive skills.

  13. Acute exercise and aerobic fitness influence selective attention during visual search

    Directory of Open Access Journals (Sweden)

    Tom eBullock

    2014-11-01

    Full Text Available Successful goal directed behavior relies on a human attention system that is flexible and able to adapt to different conditions of physiological stress. However, the effects of physical activity on multiple aspects of selective attention and whether these effects are mediated by aerobic capacity, remains unclear. The aim of the present study was to investigate the effects of a prolonged bout of physical activity on visual search performance and perceptual distraction. Two groups of participants completed a hybrid visual search flanker/response competition task in an initial baseline session and then at 17-minute intervals over a 2 hour 16 minute test period. Participants assigned to the exercise group engaged in steady-state aerobic exercise between completing blocks of the visual task, whereas participants assigned to the control group rested in between blocks. The key result was a correlation between individual differences in aerobic capacity and visual search performance, such that those individuals that were more fit performed the search task more quickly. Critically, this relationship only emerged in the exercise group after the physical activity had begun. The relationship was not present in either group at baseline and never emerged in the control group during the test period, suggesting that under these task demands, aerobic capacity may be an important determinant of visual search performance under physical stress. The results enhance current understanding about the relationship between exercise and cognition, and also inform current models of selective attention.

  14. Motivation and short-term memory in visual search: Attention's accelerator revisited.

    Science.gov (United States)

    Schneider, Daniel; Bonmassar, Claudia; Hickey, Clayton

    2017-07-13

    A cue indicating the possibility of cash reward will cause participants to perform memory-based visual search more efficiently. A recent study has suggested that this performance benefit might reflect the use of multiple memory systems: when needed, participants may maintain the to-be-remembered object in both long-term and short-term visual memory, with this redundancy benefitting target identification during search (Reinhart, McClenahan & Woodman, 2016). Here we test this compelling hypothesis. We had participants complete a memory-based visual search task involving a reward cue that either preceded presentation of the to-be-remembered target (pre-cue) or followed it (retro-cue). Following earlier work, we tracked memory representation using two components of the event-related potential (ERP): the contralateral delay activity (CDA), reflecting short-term visual memory, and the anterior P170, reflecting long-term storage. We additionally tracked attentional preparation and deployment in the contingent negative variation (CNV) and N2pc, respectively. Results show that only the reward pre-cue impacted our ERP indices of memory. However, both types of cue elicited a robust CNV, reflecting an influence on task preparation, both had equivalent impact on deployment of attention to the target, as indexed in the N2pc, and both had equivalent impact on visual search behavior. Reward prospect thus has an influence on memory-guided visual search, but this does not appear to be necessarily mediated by a change in the visual memory representations indexed by CDA. Our results demonstrate that the impact of motivation on search is not a simple product of improved memory for target templates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Reward association facilitates distractor suppression in human visual search.

    Science.gov (United States)

    Gong, Mengyuan; Yang, Feitong; Li, Sheng

    2016-04-01

    Although valuable objects are attractive in nature, people often encounter situations where they would prefer to avoid such distraction while focusing on the task goal. Contrary to the typical effect of attentional capture by a reward-associated item, we provide evidence for a facilitation effect derived from the active suppression of a high reward-associated stimulus when cuing its identity as distractor before the display of search arrays. Selection of the target is shown to be significantly faster when the distractors were in high reward-associated colour than those in low reward-associated or non-rewarded colours. This behavioural reward effect was associated with two neural signatures before the onset of the search display: the increased frontal theta oscillation and the strengthened top-down modulation from frontal to anterior temporal regions. The former suggests an enhanced working memory representation for the reward-associated stimulus and the increased need for cognitive control to override Pavlovian bias, whereas the latter indicates that the boost of inhibitory control is realized through a frontal top-down mechanism. These results suggest a mechanism in which the enhanced working memory representation of a reward-associated feature is integrated with task demands to modify attentional priority during active distractor suppression and benefit behavioural performance. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  16. The involvement of central attention in visual search is determined by task demands.

    Science.gov (United States)

    Han, Suk Won

    2017-04-01

    Attention, the mechanism by which a subset of sensory inputs is prioritized over others, operates at multiple processing stages. Specifically, attention enhances weak sensory signal at the perceptual stage, while it serves to select appropriate responses or consolidate sensory representations into short-term memory at the central stage. This study investigated the independence and interaction between perceptual and central attention. To do so, I used a dual-task paradigm, pairing a four-alternative choice task with a visual search task. The results showed that central attention for response selection was engaged in perceptual processing for visual search when the number of search items increased, thereby increasing the demand for serial allocation of focal attention. By contrast, central attention and perceptual attention remained independent as far as the demand for serial shifting of focal attention remained constant; decreasing stimulus contrast or increasing the set size of a parallel search did not evoke the involvement of central attention in visual search. These results suggest that the nature of concurrent visual search process plays a crucial role in the functional interaction between two different types of attention.

  17. Distractor Dwelling, Skipping, and Revisiting Determine Target Absent Performance in Difficult Visual Search

    Science.gov (United States)

    Horstmann, Gernot; Herwig, Arvid; Becker, Stefanie I.

    2016-01-01

    Some targets in visual search are more difficult to find than others. In particular, a target that is similar to the distractors is more difficult to find than a target that is dissimilar to the distractors. Efficiency differences between easy and difficult searches are manifest not only in target-present trials but also in target-absent trials. In fact, even physically identical displays are searched through with different efficiency depending on the searched-for target. Here, we monitored eye movements in search for a target similar to the distractors (difficult search) versus a target dissimilar to the distractors (easy search). We aimed to examine three hypotheses concerning the causes of differential search efficiencies in target-absent trials: (a) distractor dwelling (b) distractor skipping, and (c) distractor revisiting. Reaction times increased with target similarity which is consistent with existing theories and replicates earlier results. Eye movement data indicated guidance in target trials, even though search was very slow. Dwelling, skipping, and revisiting contributed to low search efficiency in difficult search, with dwelling being the strongest factor. It is argued that differences in dwell time account for a large amount of total search time differences. PMID:27574510

  18. Performance in a Visual Search Task Uniquely Predicts Reading Abilities in Third-Grade Hong Kong Chinese Children

    Science.gov (United States)

    Liu, Duo; Chen, Xi; Chung, Kevin K. H.

    2015-01-01

    This study examined the relation between the performance in a visual search task and reading ability in 92 third-grade Hong Kong Chinese children. The visual search task, which is considered a measure of visual-spatial attention, accounted for unique variance in Chinese character reading after controlling for age, nonverbal intelligence,…

  19. Target-present guessing as a function of target prevalence and accumulated information in visual search.

    Science.gov (United States)

    Peltier, Chad; Becker, Mark W

    2017-05-01

    Target prevalence influences visual search behavior. At low target prevalence, miss rates are high and false alarms are low, while the opposite is true at high prevalence. Several models of search aim to describe search behavior, one of which has been specifically intended to model search at varying prevalence levels. The multiple decision model (Wolfe & Van Wert, Current Biology, 20(2), 121--124, 2010) posits that all searches that end before the observer detects a target result in a target-absent response. However, researchers have found very high false alarms in high-prevalence searches, suggesting that prevalence rates may be used as a source of information to make "educated guesses" after search termination. Here, we further examine the ability for prevalence level and knowledge gained during visual search to influence guessing rates. We manipulate target prevalence and the amount of information that an observer accumulates about a search display prior to making a response to test if these sources of evidence are used to inform target present guess rates. We find that observers use both information about target prevalence rates and information about the proportion of the array inspected prior to making a response allowing them to make an informed and statistically driven guess about the target's presence.

  20. Working memory load predicts visual search efficiency: Evidence from a novel pupillary response paradigm.

    Science.gov (United States)

    Attar, Nada; Schneps, Matthew H; Pomplun, Marc

    2016-10-01

    An observer's pupil dilates and constricts in response to variables such as ambient and focal luminance, cognitive effort, the emotional stimulus content, and working memory load. The pupil's memory load response is of particular interest, as it might be used for estimating observers' memory load while they are performing a complex task, without adding an interruptive and confounding memory test to the protocol. One important task in which working memory's involvement is still being debated is visual search, and indeed a previous experiment by Porter, Troscianko, and Gilchrist (Quarterly Journal of Experimental Psychology, 60, 211-229, 2007) analyzed observers' pupil sizes during search to study this issue. These authors found that pupil size increased over the course of the search, and they attributed this finding to accumulating working memory load. However, since the pupil response is slow and does not depend on memory load alone, this conclusion is rather speculative. In the present study, we estimated working memory load in visual search during the presentation of intermittent fixation screens, thought to induce a low, stable level of arousal and cognitive effort. Using standard visual search and control tasks, we showed that this paradigm reduces the influence of non-memory-related factors on pupil size. Furthermore, we found an early increase in working memory load to be associated with more efficient search, indicating a significant role of working memory in the search process.

  1. Tactile search for change has less memory than visual search for change.

    Science.gov (United States)

    Yoshida, Takako; Yamaguchi, Ayumi; Tsutsui, Hideomi; Wake, Tenji

    2015-05-01

    Haptic perception of a 2D image is thought to make heavy demands on working memory. During active exploration, humans need to store the latest local sensory information and integrate it with kinesthetic information from hand and finger locations in order to generate a coherent perception. This tactile integration has not been studied as extensively as visual shape integration. In the current study, we compared working-memory capacity for tactile exploration to that of visual exploration as measured in change-detection tasks. We found smaller memory capacity during tactile exploration (approximately 1 item) compared with visual exploration (2-10 items). These differences generalized to position memory and could not be attributed to insufficient stimulus-exposure durations, acuity differences between modalities, or uncertainty over the position of items. This low capacity for tactile memory suggests that the haptic system is almost amnesic when outside the fingertips and that there is little or no cross-position integration.

  2. Visualization of information: a proposal to improve the search and access to digital resources in repositories

    Directory of Open Access Journals (Sweden)

    Paulo Alonso Gaona García

    2014-01-01

    Full Text Available Presently, the most notable challenges associated with repositories in resolving problems of searches of digital resources, lie in providing an understanding of resource classification according to a knowledge representation scheme and the relationship between them. However, one of the areas with very little research in the field is the study of visual search interfaces that provide access to relevant materials in digital repositories; more specifically, in the access of digital resources according to areas and sub-areas of a particular knowledge domain through a taxonomy classification. In this article, we focus in proposing a best practice for the search and access to relevant digital resources in repositories through visualization techniques. The article presents a prototype tool as one possible approach to facilitate searches and access to digital resources. Finally, we present the conclusions and future work in the field in order to improve access to relevant materials in digital repositories.

  3. Episodic retrieval and feature facilitation in intertrial priming of visual search

    DEFF Research Database (Denmark)

    Ásgeirsson, Árni Gunnar; Kristjánsson, Árni

    2011-01-01

    Huang, Holcombe, and Pashler (Memory & Cognition, 32, 12-20, 2004) found that priming from repetition of different features of a target in a visual search task resulted in significant response time (RT) reductions when both target brightness and size were repeated. But when only one feature...... was repeated and the other changed, RTs were longer than when neither feature was repeated. From this, they argued that priming in visual search reflected episodic retrieval of memory traces, rather than facilitation of repeated features. We tested different variations of the search task introduced by Huang et...... al., with the aim of uncovering when priming is episodic and when feature based. We found that varying the signal strength of target against distractors had a strong effect on the priming pattern. In difficult search with low signal-to-noise ratios of target against distractors, the priming patterns...

  4. Change blindness in children with ADHD: a selective impairment in visual search?

    Science.gov (United States)

    Maccari, Lisa; Casagrande, Maria; Martella, Diana; Anolfo, Mariagrazia; Rosa, Caterina; Fuentes, Luis J; Pasini, Augusto

    2013-10-01

    This study evaluated change blindness and visual search efficiency in children with ADHD in searching for central and marginal changes. A total of 36 drug-naïve children (18 ADHD/18 controls) performed a flicker task that included changes in objects of central or marginal interest. The task required observers to search for a change until they detected it. Children with ADHD performed more slowly and less accurately than did typically developing children, specifically in detecting marginal-interest changes. In contrast to more standard visual search tasks, flicker tasks seem to be more sensitive to highlight focused attention deficits in children diagnosed with ADHD. Concretely, ADHD attentional deficits were more apparent when the task involved serial top-down strategies.

  5. Assessment of brain damage in a geriatric population through use of a visual-searching task.

    Science.gov (United States)

    Turbiner, M; Derman, R M

    1980-04-01

    This study was designed to assess the discriminative capacity of a visual-searching task for brain damage, as described by Goldstein and Kyc (1978), for 10 hospitalized male, brain-damaged patients, 10 hospitalized male schizophrenic patients, and 10 normal subjects in a control group, all of whom were approximately 65 yr. old. The derived data indicated, at a statistically significant level, that the visual-searching task was effective in successfully classifying 80% of the brain-damaged sample when compared to the schizophrenic patients and discriminating 90% of the brain-damaged patients from normal subjects.

  6. Eye movements, visual search and scene memory, in an immersive virtual environment.

    Directory of Open Access Journals (Sweden)

    Dmitry Kit

    Full Text Available Visual memory has been demonstrated to play a role in both visual search and attentional prioritization in natural scenes. However, it has been studied predominantly in experimental paradigms using multiple two-dimensional images. Natural experience, however, entails prolonged immersion in a limited number of three-dimensional environments. The goal of the present experiment was to recreate circumstances comparable to natural visual experience in order to evaluate the role of scene memory in guiding eye movements in a natural environment. Subjects performed a continuous visual-search task within an immersive virtual-reality environment over three days. We found that, similar to two-dimensional contexts, viewers rapidly learn the location of objects in the environment over time, and use spatial memory to guide search. Incidental fixations did not provide obvious benefit to subsequent search, suggesting that semantic contextual cues may often be just as efficient, or that many incidentally fixated items are not held in memory in the absence of a specific task. On the third day of the experience in the environment, previous search items changed in color. These items were fixated upon with increased probability relative to control objects, suggesting that memory-guided prioritization (or Surprise may be a robust mechanisms for attracting gaze to novel features of natural environments, in addition to task factors and simple spatial saliency.

  7. Memory and visual search in naturalistic 2D and 3D environments.

    Science.gov (United States)

    Li, Chia-Ling; Aivar, M Pilar; Kit, Dmitry M; Tong, Matthew H; Hayhoe, Mary M

    2016-06-01

    The role of memory in guiding attention allocation in daily behaviors is not well understood. In experiments with two-dimensional (2D) images, there is mixed evidence about the importance of memory. Because the stimulus context in laboratory experiments and daily behaviors differs extensively, we investigated the role of memory in visual search, in both two-dimensional (2D) and three-dimensional (3D) environments. A 3D immersive virtual apartment composed of two rooms was created, and a parallel 2D visual search experiment composed of snapshots from the 3D environment was developed. Eye movements were tracked in both experiments. Repeated searches for geometric objects were performed to assess the role of spatial memory. Subsequently, subjects searched for realistic context objects to test for incidental learning. Our results show that subjects learned the room-target associations in 3D but less so in 2D. Gaze was increasingly restricted to relevant regions of the room with experience in both settings. Search for local contextual objects, however, was not facilitated by early experience. Incidental fixations to context objects do not necessarily benefit search performance. Together, these results demonstrate that memory for global aspects of the environment guides search by restricting allocation of attention to likely regions, whereas task relevance determines what is learned from the active search experience. Behaviors in 2D and 3D environments are comparable, although there is greater use of memory in 3D.

  8. Ontology-Driven Search and Triage: Design of a Web-Based Visual Interface for MEDLINE.

    Science.gov (United States)

    Demelo, Jonathan; Parsons, Paul; Sedig, Kamran

    2017-02-02

    Diverse users need to search health and medical literature to satisfy open-ended goals such as making evidence-based decisions and updating their knowledge. However, doing so is challenging due to at least two major difficulties: (1) articulating information needs using accurate vocabulary and (2) dealing with large document sets returned from searches. Common search interfaces such as PubMed do not provide adequate support for exploratory search tasks. Our objective was to improve support for exploratory search tasks by combining two strategies in the design of an interactive visual interface by (1) using a formal ontology to help users build domain-specific knowledge and vocabulary and (2) providing multi-stage triaging support to help mitigate the information overload problem. We developed a Web-based tool, Ontology-Driven Visual Search and Triage Interface for MEDLINE (OVERT-MED), to test our design ideas. We implemented a custom searchable index of MEDLINE, which comprises approximately 25 million document citations. We chose a popular biomedical ontology, the Human Phenotype Ontology (HPO), to test our solution to the vocabulary problem. We implemented multistage triaging support in OVERT-MED, with the aid of interactive visualization techniques, to help users deal with large document sets returned from searches. Formative evaluation suggests that the design features in OVERT-MED are helpful in addressing the two major difficulties described above. Using a formal ontology seems to help users articulate their information needs with more accurate vocabulary. In addition, multistage triaging combined with interactive visualizations shows promise in mitigating the information overload problem. Our strategies appear to be valuable in addressing the two major problems in exploratory search. Although we tested OVERT-MED with a particular ontology and document collection, we anticipate that our strategies can be transferred successfully to other contexts.

  9. Transcranial direct current stimulation (tDCS) facilitates overall visual search response times but does not interact with visual search task factors.

    Science.gov (United States)

    Sung, Kyongje; Gordon, Barry

    2018-01-01

    Whether transcranial direct current stimulation (tDCS) affects mental functions, and how any such effects arise from its neural effects, continue to be debated. We investigated whether tDCS applied over the visual cortex (Oz) with a vertex (Cz) reference might affect response times (RTs) in a visual search task. We also examined whether any significant tDCS effects would interact with task factors (target presence, discrimination difficulty, and stimulus brightness) that are known to selectively influence one or the other of the two information processing stages posited by current models of visual search. Based on additive factor logic, we expected that the pattern of interactions involving a significant tDCS effect could help us colocalize the tDCS effect to one (or both) of the processing stages. In Experiment 1 (n = 12), anodal tDCS improved RTs significantly; cathodal tDCS produced a nonsignificant trend toward improvement. However, there were no interactions between the anodal tDCS effect and target presence or discrimination difficulty. In Experiment 2 (n = 18), we manipulated stimulus brightness along with target presence and discrimination difficulty. Anodal and cathodal tDCS both produced significant improvements in RTs. Again, the tDCS effects did not interact with any of the task factors. In Experiment 3 (n = 16), electrodes were placed at Cz and on the upper arm, to test for a possible effect of incidental stimulation of the motor regions under Cz. No effect of tDCS on RTs was found. These findings strengthen the case for tDCS having real effects on cerebral information processing. However, these effects did not clearly arise from either of the two processing stages of the visual search process. We suggest that this is because tDCS has a DIFFUSE, pervasive action across the task-relevant neuroanatomical region(s), not a discrete effect in terms of information processing stages.

  10. Memory for found targets interferes with subsequent performance in multiple-target visual search.

    Science.gov (United States)

    Cain, Matthew S; Mitroff, Stephen R

    2013-10-01

    Multiple-target visual searches--when more than 1 target can appear in a given search display--are commonplace in radiology, airport security screening, and the military. Whereas 1 target is often found accurately, additional targets are more likely to be missed in multiple-target searches. To better understand this decrement in 2nd-target detection, here we examined 2 potential forms of interference that can arise from finding a 1st target: interference from the perceptual salience of the 1st target (a now highly relevant distractor in a known location) and interference from a newly created memory representation for the 1st target. Here, we found that removing found targets from the display or making them salient and easily segregated color singletons improved subsequent search accuracy. However, replacing found targets with random distractor items did not improve subsequent search accuracy. Removing and highlighting found targets likely reduced both a target's visual salience and its memory load, whereas replacing a target removed its visual salience but not its representation in memory. Collectively, the current experiments suggest that the working memory load of a found target has a larger effect on subsequent search accuracy than does its perceptual salience. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  11. Stronger interference from distractors in the right hemifield during visual search.

    Science.gov (United States)

    Carlei, Christophe; Kerzel, Dirk

    2018-03-01

    The orientation-bias hypothesis states that there is a bias to attend to the right visual hemifield (RVF) when there is spatial competition between stimuli in the left and right hemifield [Pollmann, S. (1996). A pop-out induced extinction-like phenomenon in neurologically intact subjects. Neuropsychologia, 34(5), 413-425. doi: 10.1016/0028-3932(95)00125-5 ]. In support of this hypothesis, stronger interference was reported for RVF distractors with contralateral targets. In contrast, previous studies using rapid serial visual presentation (RSVP) found stronger interference from distractors in the left visual hemifield (LVF). We used the additional singleton paradigm to test whether this discrepancy was due to the different distractor features that were employed (colour vs. orientation). Interference from the colour distractor with contralateral targets was larger in the RVF than in the LVF. However, the asymmetrical interference disappeared when observers had to search for an inconspicuous colour target instead of the inconspicuous shape target. We suggest that the LVF orienting-bias is limited to situations where search is driven by bottom-up saliency (singleton search) instead of top-down search goals (feature search). In contrast, analysis of the literature suggests the opposite for the LVF bias in RSVP tasks. Thus, the attentional asymmetry may depend on whether the task involves temporal or spatial competition, and whether search is based on bottom-up or top-down signals.

  12. Explicit awareness supports conditional visual search in the retrieval guidance paradigm.

    Science.gov (United States)

    Buttaccio, Daniel R; Lange, Nicholas D; Hahn, Sowon; Thomas, Rick P

    2014-01-01

    In four experiments we explored whether participants would be able to use probabilistic prompts to simplify perceptually demanding visual search in a task we call the retrieval guidance paradigm. On each trial a memory prompt appeared prior to (and during) the search task and the diagnosticity of the prompt(s) was manipulated to provide complete, partial, or non-diagnostic information regarding the target's color on each trial (Experiments 1-3). In Experiment 1 we found that the more diagnostic prompts was associated with faster visual search performance. However, similar visual search behavior was observed in Experiment 2 when the diagnosticity of the prompts was eliminated, suggesting that participants in Experiment 1 were merely relying on base rate information to guide search and were not utilizing the prompts. In Experiment 3 participants were informed of the relationship between the prompts and the color of the target and this was associated with faster search performance relative to Experiment 1, suggesting that the participants were using the prompts to guide search. Additionally, in Experiment 3 a knowledge test was implemented and performance in this task was associated with qualitative differences in search behavior such that participants that were able to name the color(s) most associated with the prompts were faster to find the target than participants who were unable to do so. However, in Experiments 1-3 diagnosticity of the memory prompt was manipulated via base rate information, making it possible that participants were merely relying on base rate information to inform search in Experiment 3. In Experiment 4 we manipulated diagnosticity of the prompts without manipulating base rate information and found a similar pattern of results as Experiment 3. Together, the results emphasize the importance of base rate and diagnosticity information in visual search behavior. In the General discussion section we explore how a recent computational model of

  13. Increased Complexities in Visual Search Behavior in Skilled Players for a Self-Paced Aiming Task

    Directory of Open Access Journals (Sweden)

    Jingyi S. Chia

    2017-06-01

    Full Text Available The badminton serve is an important shot for winning a rally in a match. It combines good technique with the ability to accurately integrate visual information from the shuttle, racket, opponent, and intended landing point. Despite its importance and repercussive nature, to date no study has looked at the visual search behaviors during badminton service in the singles discipline. Unlike anticipatory tasks (e.g., shot returns, the serve presents an opportunity to explore the role of visual search behaviors in movement control for self-paced tasks. Accordingly, this study examined skill-related differences in visual behavior during the badminton singles serve. Skilled (n = 12 and less skilled (n = 12 participants performed 30 serves to a live opponent, while real-time eye movements were captured using a mobile gaze registration system. Frame-by-frame analyses of 662 serves were made and the skilled players took a longer preparatory time before serving. Visual behavior of the skilled players was characterized by significantly greater number of fixations on more areas of interest per trial than the less skilled. In addition, the skilled players spent a significantly longer time fixating on the court and net, whereas the less skilled players found the shuttle to be more informative. Quiet eye (QE duration (indicative of superior sports performance however, did not differ significantly between groups which has implications on the perceived importance of QE in the badminton serve. Moreover, while visual behavior differed by skill level, considerable individual differences were also observed especially within the skilled players. This augments the need for not just group-level analyses, but individualized analysis for a more accurate representation of visual behavior. Findings from this study thus provide an insight to the possible visual search strategies as players serve in net-barrier games. Moreover, this study highlighted an important aspect of

  14. Inter-trial priming does not affect attentional priority in asymmetric visual search

    Directory of Open Access Journals (Sweden)

    Liana eAmunts

    2014-08-01

    Full Text Available Visual search is considerably speeded when the target’s characteristics remain constant across successive selections. Here, we investigated whether such inter-trial priming increases the target’s attentional priority, by examining whether target repetition reduces search efficiency during serial search. As the study of inter-trial priming requires the target and distractors to exchange roles unpredictably, it has mostly been confined to singleton searches, which typically yield efficient search. We therefore resorted to two singleton searches known to yield relatively inefficient performance, that is, searches in which the target does not pop out. Participants searched for a veridical angry face among neutral ones or vice-versa, either upright or inverted (Experiment 1 or for a Q among Os or vice-versa (Experiment 2. In both experiments, we found substantial intertrial priming that did not improve search efficiency. In addition, intertrial priming was asymmetric and occurred only when the more salient target repeated. We conclude that intertrial priming does not modulate attentional priority allocation and that it occurs in asymmetric search only when the target is characterized by an additional feature that is consciously perceived.

  15. Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search.

    Science.gov (United States)

    de Vries, Ingmar E J; van Driel, Joram; Olivers, Christian N L

    2017-02-08

    Current models of visual search assume that search is guided by an active visual working memory representation of what we are currently looking for. This attentional template for currently relevant stimuli can be dissociated from accessory memory representations that are only needed prospectively, for a future task, and that should be prevented from guiding current attention. However, it remains unclear what electrophysiological mechanisms dissociate currently relevant (serving upcoming selection) from prospectively relevant memories (serving future selection). We measured EEG of 20 human subjects while they performed two consecutive visual search tasks. Before the search tasks, a cue instructed observers which item to look for first (current template) and which second (prospective template). During the delay leading up to the first search display, we found clear suppression of α band (8-14 Hz) activity in regions contralateral to remembered items, comprising both local power and interregional phase synchronization within a posterior parietal network. Importantly, these lateralization effects were stronger when the memory item was currently relevant (i.e., for the first search) compared with when it was prospectively relevant (i.e., for the second search), consistent with current templates being prioritized over future templates. In contrast, event-related potential analysis revealed that the contralateral delay activity was similar for all conditions, suggesting no difference in storage. Together, these findings support the idea that posterior α oscillations represent a state of increased processing or excitability in task-relevant cortical regions, and reflect enhanced cortical prioritization of memory representations that serve as a current selection filter. SIGNIFICANCE STATEMENT Our days are filled with looking for relevant objects while ignoring irrelevant visual information. Such visual search activity is thought to be driven by current goals activated in

  16. Where perception meets memory: a review of repetition priming in visual search tasks.

    Science.gov (United States)

    Kristjánsson, Arni; Campana, Gianluca

    2010-01-01

    What we have recently seen and attended to strongly influences how we subsequently allocate visual attention. A clear example is how repeated presentation of an object's features or location in visual search tasks facilitates subsequent detection or identification of that item, a phenomenon known as priming. Here, we review a large body of results from priming studies that suggest that a short-term implicit memory system guides our attention to recently viewed items. The nature of this memory system and the processing level at which visual priming occurs are still debated. Priming might be due to activity modulations of low-level areas coding simple stimulus characteristics or to higher level episodic memory representations of whole objects or visual scenes. Indeed, recent evidence indicates that only minor changes to the stimuli used in priming studies may alter the processing level at which priming occurs. We also review recent behavioral, neuropsychological, and neurophysiological evidence that indicates that the priming patterns are reflected in activity modulations at multiple sites along the visual pathways. We furthermore suggest that studies of priming in visual search may potentially shed important light on the nature of cortical visual representations. Our conclusion is that priming occurs at many different levels of the perceptual hierarchy, reflecting activity modulations ranging from lower to higher levels, depending on the stimulus, task, and context-in fact, the neural loci that are involved in the analysis of the stimuli for which priming effects are seen.

  17. Predicting Airport Screening Officers' Visual Search Competency With a Rapid Assessment.

    Science.gov (United States)

    Mitroff, Stephen R; Ericson, Justin M; Sharpe, Benjamin

    2018-03-01

    Objective The study's objective was to assess a new personnel selection and assessment tool for aviation security screeners. A mobile app was modified to create a tool, and the question was whether it could predict professional screeners' on-job performance. Background A variety of professions (airport security, radiology, the military, etc.) rely on visual search performance-being able to detect targets. Given the importance of such professions, it is necessary to maximize performance, and one means to do so is to select individuals who excel at visual search. A critical question is whether it is possible to predict search competency within a professional search environment. Method Professional searchers from the USA Transportation Security Administration (TSA) completed a rapid assessment on a tablet-based X-ray simulator (XRAY Screener, derived from the mobile technology app Airport Scanner; Kedlin Company). The assessment contained 72 trials that were simulated X-ray images of bags. Participants searched for prohibited items and tapped on them with their finger. Results Performance on the assessment significantly related to on-job performance measures for the TSA officers such that those who were better XRAY Screener performers were both more accurate and faster at the actual airport checkpoint. Conclusion XRAY Screener successfully predicted on-job performance for professional aviation security officers. While questions remain about the underlying cognitive mechanisms, this quick assessment was found to significantly predict on-job success for a task that relies on visual search performance. Application It may be possible to quickly assess an individual's visual search competency, which could help organizations select new hires and assess their current workforce.

  18. From Foreground to Background: How Task-Neutral Context Influences Contextual Cueing of Visual Search.

    Science.gov (United States)

    Zang, Xuelian; Geyer, Thomas; Assumpção, Leonardo; Müller, Hermann J; Shi, Zhuanghua

    2016-01-01

    Selective attention determines the effectiveness of implicit contextual learning (e.g., Jiang and Leung, 2005). Visual foreground-background segmentation, on the other hand, is a key process in the guidance of attention (Wolfe, 2003). In the present study, we examined the impact of foreground-background segmentation on contextual cueing of visual search in three experiments. A visual search display, consisting of distractor 'L's and a target 'T', was overlaid on a task-neutral cuboid on the same depth plane (Experiment 1), on stereoscopically separated depth planes (Experiment 2), or spread over the entire display on the same depth plane (Experiment 3). Half of the search displays contained repeated target-distractor arrangements, whereas the other half was always newly generated. The task-neutral cuboid was constant during an initial training session, but was either rotated by 90° or entirely removed in the subsequent test sessions. We found that the gains resulting from repeated presentation of display arrangements during training (i.e., contextual-cueing effects) were diminished when the cuboid was changed or removed in Experiment 1, but remained intact in Experiments 2 and 3 when the cuboid was placed in a different depth plane, or when the items were randomly spread over the whole display but not on the edges of the cuboid. These findings suggest that foreground-background segmentation occurs prior to contextual learning, and only objects/arrangements that are grouped as foreground are learned over the course of repeated visual search.

  19. Can a short nap and bright light function as implicit learning and visual search enhancers?

    Science.gov (United States)

    Kaida, Kosuke; Takeda, Yuji; Tsuzuki, Kazuyo

    2012-01-01

    The present study examined effects of a short nap (20 min) and/or bright light (2000 lux) on visual search and implicit learning in a contextual cueing task. Fifteen participants performed a contextual cueing task twice a day (1200-1330 h and 1430-1600 h) and scored subjective sleepiness before and after a short afternoon nap or a break period. Participants served a total of four experimental conditions (control, short nap, bright light and short nap with bright light). During the second task, bright light treatment (BLT) was applied in the two of the four conditions. Participants performed both tasks in a dimly lit environment except during the light treatment. Results showed that a short nap reduced subjective sleepiness and improved visual search time, but it did not affect implicit learning. Bright light reduced subjective sleepiness. A short nap in the afternoon could be a countermeasure against sleepiness and an enhancer for visual search. Practitioner Summary: The study examined effects of a short afternoon nap (20 min) and/or bright light (2000 lux) on visual search and implicit learning. A short nap is a powerful countermeasure against sleepiness compared to bright light exposure in the afternoon.

  20. Visual search in school-aged children with unilateral brain lesions

    NARCIS (Netherlands)

    Netelenbos, J.B.; de Rooij, L.

    2004-01-01

    In this preliminary study, visual search for targets within and beyond the initial field of view was investigated in seven school-aged children (five females, two males; mean age at testing 8 years 10 months, SD 1 year 3 months; range 6 to 10 years) with various acquired, postnatal, focal brain

  1. The function of visual search and memory in sequential looking tasks

    NARCIS (Netherlands)

    J. Epelboim (Julie); R.M. Steinman (Robert); E. Kowler (Eileen); M. Edwards (Mark); Z. Pizlo (Zygmunt); D.W. Erkelens (Dirk Willem); H. Collewijn (Han)

    1995-01-01

    textabstractEye and head movements were recorded as unrestrained subjects tapped or only looked at nearby targets. Scanning patterns were the same in both tasks: subjects looked at each target before tapping it; visual search had similar speeds and gaze-shift accuracies. Looking however, took longer

  2. Attentional Capture by Salient Distractors during Visual Search Is Determined by Temporal Task Demands

    DEFF Research Database (Denmark)

    Kiss, Monika; Grubert, Anna; Petersen, Anders

    2012-01-01

    The question whether attentional capture by salient but taskirrelevant visual stimuli is triggered in a bottom–up fashion or depends on top–down task settings is still unresolved. Strong support for bottom–up capture was obtained in the additional singleton task, in which search arrays were visible...

  3. Event-related potentials dissociate perceptual from response-related age effects in visual search

    DEFF Research Database (Denmark)

    Wiegand, Iris; Müller, Hermann J.; Finke, Kathrin

    2013-01-01

    Attentional decline plays a major role in cognitive changes with aging. However, which specific aspects of attention contribute to this decline is as yet little understood. To identify the contributions of various potential sources of age decrements in visual search, we combined response time...... intertrial changes required more executively controlled processes, such as flexible stimulus-response (re-)mapping across trials....

  4. Implicit short- and long-term memory direct our gaze in visual search.

    Science.gov (United States)

    Kruijne, Wouter; Meeter, Martijn

    2016-04-01

    Visual attention is strongly affected by the past: both by recent experience and by long-term regularities in the environment that are encoded in and retrieved from memory. In visual search, intertrial repetition of targets causes speeded response times (short-term priming). Similarly, targets that are presented more often than others may facilitate search, even long after it is no longer present (long-term priming). In this study, we investigate whether such short-term priming and long-term priming depend on dissociable mechanisms. By recording eye movements while participants searched for one of two conjunction targets, we explored at what stages of visual search different forms of priming manifest. We found both long- and short- term priming effects. Long-term priming persisted long after the bias was present, and was again found even in participants who were unaware of a color bias. Short- and long-term priming affected the same stage of the task; both biased eye movements towards targets with the primed color, already starting with the first eye movement. Neither form of priming affected the response phase of a trial, but response repetition did. The results strongly suggest that both long- and short-term memory can implicitly modulate feedforward visual processing.

  5. Audio Cues to Assist Visual Search in Robotic System Operator Control Unit Displays

    Science.gov (United States)

    2005-12-01

    Christopher C. Stachowiak , and Michael A. Lattin ARL-TR-3632 December 2005 Approved for...Assist Visual Search in Robotic System Operator Control Unit Displays Ellen C. Haas, Ramakrishna S. Pillalamarri, Christopher C. Stachowiak , and...5e. TASK NUMBER 6. AUTHOR(S) Ellen C. Haas, Ramakrishna S. Pillalamarri, Christopher C. Stachowiak , and Michael A. Lattin (all of ARL

  6. An individual differences approach to multiple-target visual search errors: How search errors relate to different characteristics of attention.

    Science.gov (United States)

    Adamo, Stephen H; Cain, Matthew S; Mitroff, Stephen R

    2017-12-01

    A persistent problem in visual search is that searchers are more likely to miss a target if they have already found another in the same display. This phenomenon, the Subsequent Search Miss (SSM) effect, has remained despite being a known issue for decades. Increasingly, evidence supports a resource depletion account of SSM errors-a previously detected target consumes attentional resources leaving fewer resources available for the processing of a second target. However, "attention" is broadly defined and is composed of many different characteristics, leaving considerable uncertainty about how attention affects second-target detection. The goal of the current study was to identify which attentional characteristics (i.e., selection, limited capacity, modulation, and vigilance) related to second-target misses. The current study compared second-target misses to an attentional blink task and a vigilance task, which both have established measures that were used to operationally define each of four attentional characteristics. Second-target misses in the multiple-target search were correlated with (1) a measure of the time it took for the second target to recovery from the blink in the attentional blink task (i.e., modulation), and (2) target sensitivity (d') in the vigilance task (i.e., vigilance). Participants with longer recovery and poorer vigilance had more second-target misses in the multiple-target visual search task. The results add further support to a resource depletion account of SSM errors and highlight that worse modulation and poor vigilance reflect a deficit in attentional resources that can account for SSM errors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Centre-of-Gravity Fixations in Visual Search: When Looking at Nothing Helps to Find Something

    Directory of Open Access Journals (Sweden)

    Dustin Venini

    2014-01-01

    Full Text Available In visual search, some fixations are made between stimuli on empty regions, commonly referred to as “centre-of-gravity” fixations (henceforth: COG fixations. Previous studies have shown that observers with task expertise show more COG fixations than novices. This led to the view that COG fixations reflect simultaneous encoding of multiple stimuli, allowing more efficient processing of task-related items. The present study tested whether COG fixations also aid performance in visual search tasks with unfamiliar and abstract stimuli. Moreover, to provide evidence for the multiple-item processing view, we analysed the effects of COG fixations on the number and dwell times of stimulus fixations. The results showed that (1 search efficiency increased with increasing COG fixations even in search for unfamiliar stimuli and in the absence of special higher-order skills, (2 COG fixations reliably reduced the number of stimulus fixations and their dwell times, indicating processing of multiple distractors, and (3 the proportion of COG fixations was dynamically adapted to potential information gain of COG locations. A second experiment showed that COG fixations are diminished when stimulus positions unpredictably vary across trials. Together, the results support the multiple-item processing view, which has important implications for current theories of visual search.

  8. VisualRank: applying PageRank to large-scale image search.

    Science.gov (United States)

    Jing, Yushi; Baluja, Shumeet

    2008-11-01

    Because of the relative ease in understanding and processing text, commercial image-search systems often rely on techniques that are largely indistinguishable from text-search. Recently, academic studies have demonstrated the effectiveness of employing image-based features to provide alternative or additional signals. However, it remains uncertain whether such techniques will generalize to a large number of popular web queries, and whether the potential improvement to search quality warrants the additional computational cost. In this work, we cast the image-ranking problem into the task of identifying "authority" nodes on an inferred visual similarity graph and propose VisualRank to analyze the visual link structures among images. The images found to be "authorities" are chosen as those that answer the image-queries well. To understand the performance of such an approach in a real system, we conducted a series of large-scale experiments based on the task of retrieving images for 2000 of the most popular products queries. Our experimental results show significant improvement, in terms of user satisfaction and relevancy, in comparison to the most recent Google Image Search results. Maintaining modest computational cost is vital to ensuring that this procedure can be used in practice; we describe the techniques required to make this system practical for large scale deployment in commercial search engines.

  9. Active visual search in non-stationary scenes: coping with temporal variability and uncertainty

    Science.gov (United States)

    Ušćumlić, Marija; Blankertz, Benjamin

    2016-02-01

    Objective. State-of-the-art experiments for studying neural processes underlying visual cognition often constrain sensory inputs (e.g., static images) and our behavior (e.g., fixed eye-gaze, long eye fixations), isolating or simplifying the interaction of neural processes. Motivated by the non-stationarity of our natural visual environment, we investigated the electroencephalography (EEG) correlates of visual recognition while participants overtly performed visual search in non-stationary scenes. We hypothesized that visual effects (such as those typically used in human-computer interfaces) may increase temporal uncertainty (with reference to fixation onset) of cognition-related EEG activity in an active search task and therefore require novel techniques for single-trial detection. Approach. We addressed fixation-related EEG activity in an active search task with respect to stimulus-appearance styles and dynamics. Alongside popping-up stimuli, our experimental study embraces two composite appearance styles based on fading-in, enlarging, and motion effects. Additionally, we explored whether the knowledge obtained in the pop-up experimental setting can be exploited to boost the EEG-based intention-decoding performance when facing transitional changes of visual content. Main results. The results confirmed our initial hypothesis that the dynamic of visual content can increase temporal uncertainty of the cognition-related EEG activity in active search with respect to fixation onset. This temporal uncertainty challenges the pivotal aim to keep the decoding performance constant irrespective of visual effects. Importantly, the proposed approach for EEG decoding based on knowledge transfer between the different experimental settings gave a promising performance. Significance. Our study demonstrates that the non-stationarity of visual scenes is an important factor in the evolution of cognitive processes, as well as in the dynamic of ocular behavior (i.e., dwell time and

  10. Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task

    Directory of Open Access Journals (Sweden)

    Claire eWardak

    2012-06-01

    Full Text Available The posterior parietal cortex participates to numerous cognitive functions, from perceptual to attentional and decisional processes. However, the same functions have also been attributed to the frontal cortex. We previously conducted a series of reversible inactivations of the lateral intraparietal area (LIP and of the frontal eye field (FEF in the monkey which showed impairments in covert visual search performance, characterized mainly by an increase in the mean reaction time (RT necessary to detect a contralesional target. Only subtle differences were observed between the inactivation effects in both areas. In particular, the magnitude of the deficit was dependant of search task difficulty for LIP, but not for FEF.In the present study, we re-examine these data in order to try to dissociate the specific involvement of these two regions, by considering the entire RT distribution instead of mean RT. We use the LATER model to help us interpret the effects of the inactivations with regard to information accumulation rate and decision processes. We show that: 1 different search strategies can be used by monkeys to perform visual search, either by processing the visual scene in parallel, or by combining parallel and serial processes; 2 LIP and FEF inactivations have very different effects on the RT distributions in the two monkeys. Although our results are not conclusive with regards to the exact functional mechanisms affected by the inactivations, the effects we observe on RT distributions could be accounted by an involvement of LIP in saliency representation or decision-making, and an involvement of FEF in attentional shifts and perception. Finally, we observe that the use of the LATER model is limited in the context of a visual search as it cannot fit all the behavioural strategies encountered. We propose that the diversity in search strategies observed in our monkeys also exists in individual human subjects and should be considered in future

  11. A Lifelog Browser for Visualization and Search of Mobile Everyday-Life

    Directory of Open Access Journals (Sweden)

    Keum-Sung Hwang

    2014-01-01

    Full Text Available Mobile devices can now handle a great deal of information thanks to the convergence of diverse functionalities. Mobile environments have already shown great potential in terms of providing customized service to users because they can record meaningful and private information continually for long periods of time. The research for understanding, searching and summarizing the everyday-life of human has received increasing attention in recent years due to the digital convergence. In this paper, we propose a mobile life browser, which visualizes and searches human's mobile life based on the contents and context of lifelog data. The mobile life browser is for searching the personal information effectively collected on his/her mobile device and for supporting the concept-based searching method by using concept networks and Bayesian networks. In the experiments, we collected the real mobile log data from three users for a month and visualized the mobile lives of the users with the mobile life browser developed. Some tests on searching tasks confirmed that the result using the proposed concept-based searching method is promising.

  12. Footprints: A Visual Search Tool that Supports Discovery and Coverage Tracking.

    Science.gov (United States)

    Isaacs, Ellen; Domico, Kelly; Ahern, Shane; Bart, Eugene; Singhal, Mudita

    2014-12-01

    Searching a large document collection to learn about a broad subject involves the iterative process of figuring out what to ask, filtering the results, identifying useful documents, and deciding when one has covered enough material to stop searching. We are calling this activity "discoverage," discovery of relevant material and tracking coverage of that material. We built a visual analytic tool called Footprints that uses multiple coordinated visualizations to help users navigate through the discoverage process. To support discovery, Footprints displays topics extracted from documents that provide an overview of the search space and are used to construct searches visuospatially. Footprints allows users to triage their search results by assigning a status to each document (To Read, Read, Useful), and those status markings are shown on interactive histograms depicting the user's coverage through the documents across dates, sources, and topics. Coverage histograms help users notice biases in their search and fill any gaps in their analytic process. To create Footprints, we used a highly iterative, user-centered approach in which we conducted many evaluations during both the design and implementation stages and continually modified the design in response to feedback.

  13. The Importance of the Eye Area in Face Identification Abilities and Visual Search Strategies in Persons with Asperger Syndrome

    Science.gov (United States)

    Falkmer, Marita; Larsson, Matilda; Bjallmark, Anna; Falkmer, Torbjorn

    2010-01-01

    Partly claimed to explain social difficulties observed in people with Asperger syndrome, face identification and visual search strategies become important. Previous research findings are, however, disparate. In order to explore face identification abilities and visual search strategies, with special focus on the importance of the eye area, 24…

  14. Evaluation of a prototype search and visualization system for exploring scientific communities.

    Science.gov (United States)

    Bales, Michael E; Kaufman, David R; Johnson, Stephen B

    2009-11-14

    Searches of bibliographic databases generate lists of articles but do little to reveal connections between authors, institutions, and grants. As a result, search results cannot be fully leveraged. To address this problem we developed Sciologer, a prototype search and visualization system. Sciologer presents the results of any PubMed query as an interactive network diagram of the above elements. We conducted a cognitive evaluation with six neuroscience and six obesity researchers. Researchers used the system effectively. They used geographic, color, and shape metaphors to describe community structure and made accurate inferences pertaining to a) collaboration among research groups; b) prominence of individual researchers; and c) differentiation of expertise. The tool confirmed certain beliefs, disconfirmed others, and extended their understanding of their own discipline. The majority indicated the system offered information of value beyond a traditional PubMed search and that they would use the tool if available.

  15. Priming of Visual Search Facilitates Attention Shifts: Evidence From Object-Substitution Masking.

    Science.gov (United States)

    Kristjánsson, Árni

    2016-03-01

    Priming of visual search strongly affects visual function, releasing items from crowding and during free-choice primed targets are chosen over unprimed ones. Two accounts of priming have been proposed: attentional facilitation of primed features and postperceptual episodic memory retrieval that involves mapping responses to visual events. Here, well-known masking effects were used to assess the two accounts. Object-substitution masking has been considered to reflect attentional processing: It does not occur when a target is precued and is strengthened when distractors are present. Conversely, metacontrast masking has been connected to lower level processing where attention exerts little effect. If priming facilitates attention shifts, it should mitigate object-substitution masking, while lower level masking might not be similarly influenced. Observers searched for an odd-colored target among distractors. Unpredictably (on 20% of trials), object-substitution masks or metacontrast masks appeared around the target. Object-substitution masking was strongly mitigated for primed target colors, while metacontrast masking was mostly unaffected. This argues against episodic retrieval accounts of priming, placing the priming locus firmly within the realm of attentional processing. The results suggest that priming of visual search facilitates attention shifts to the target, which allows better spatiotemporal resolution that overcomes object-substitution masking. © The Author(s) 2015.

  16. Direction of Auditory Pitch-Change Influences Visual Search for Slope From Graphs.

    Science.gov (United States)

    Parrott, Stacey; Guzman-Martinez, Emmanuel; Orte, Laura; Grabowecky, Marcia; Huntington, Mark D; Suzuki, Satoru

    2015-01-01

    Linear trend (slope) is important information conveyed by graphs. We investigated how sounds influenced slope detection in a visual search paradigm. Four bar graphs or scatter plots were presented on each trial. Participants looked for a positive-slope or a negative-slope target (in blocked trials), and responded to targets in a go or no-go fashion. For example, in a positive-slope-target block, the target graph displayed a positive slope while other graphs displayed negative slopes (a go trial), or all graphs displayed negative slopes (a no-go trial). When an ascending or descending sound was presented concurrently, ascending sounds slowed detection of negative-slope targets whereas descending sounds slowed detection of positive-slope targets. The sounds had no effect when they immediately preceded the visual search displays, suggesting that the results were due to crossmodal interaction rather than priming. The sounds also had no effect when targets were words describing slopes, such as "positive," "negative," "increasing," or "decreasing," suggesting that the results were unlikely due to semantic-level interactions. Manipulations of spatiotemporal similarity between sounds and graphs had little effect. These results suggest that ascending and descending sounds influence visual search for slope based on a general association between the direction of auditory pitch-change and visual linear trend.

  17. Task-dependent modulation of word processing mechanisms during modified visual search tasks.

    Science.gov (United States)

    Dampure, Julien; Benraiss, Abdelrhani; Vibert, Nicolas

    2016-01-01

    During visual search for words, the impact of the visual and semantic features of words varies as a function of the search task. This event-related potential (ERP) study focused on the way these features of words are used to detect similarities between the distractor words that are glanced at and the target word, as well as to then reject the distractor words. The participants had to search for a target word that was either given literally or defined by a semantic clue among words presented sequentially. The distractor words included words that resembled the target and words that were semantically related to the target. The P2a component was the first component to be modulated by the visual and/or semantic similarity of distractors to the target word, and these modulations varied according to the task. The same held true for the later N300 and N400 components, which confirms that, depending on the task, distinct processing pathways were sensitized through attentional modulation. Hence, the process that matches what is perceived with the target acts during the first 200 ms after word presentation, and both early detection and late rejection processes of words depend on the search task and on the representation of the target stored in memory.

  18. The eye movements of dyslexic children during reading and visual search: impact of the visual attention span.

    Science.gov (United States)

    Prado, Chloé; Dubois, Matthieu; Valdois, Sylviane

    2007-09-01

    The eye movements of 14 French dyslexic children having a VA span reduction and 14 normal readers were compared in two tasks of visual search and text reading. The dyslexic participants made a higher number of rightward fixations in reading only. They simultaneously processed the same low number of letters in both tasks whereas normal readers processed far more letters in reading. Importantly, the children's VA span abilities related to the number of letters simultaneously processed in reading. The atypical eye movements of some dyslexic readers in reading thus appear to reflect difficulties to increase their VA span according to the task request.

  19. Adding a Visualization Feature to Web Search Engines: It’s Time

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Pak C.

    2008-11-11

    Since the first world wide web (WWW) search engine quietly entered our lives in 1994, the “information need” behind web searching has rapidly grown into a multi-billion dollar business that dominates the internet landscape, drives e-commerce traffic, propels global economy, and affects the lives of the whole human race. Today’s search engines are faster, smarter, and more powerful than those released just a few years ago. With the vast investment pouring into research and development by leading web technology providers and the intense emotion behind corporate slogans such as “win the web” or “take back the web,” I can’t help but ask why are we still using the very same “text-only” interface that was used 13 years ago to browse our search engine results pages (SERPs)? Why has the SERP interface technology lagged so far behind in the web evolution when the corresponding search technology has advanced so rapidly? In this article I explore some current SERP interface issues, suggest a simple but practical visual-based interface design approach, and argue why a visual approach can be a strong candidate for tomorrow’s SERP interface.

  20. Visual search for emotional expressions: Effect of stimulus set on anger and happiness superiority.

    Science.gov (United States)

    Savage, Ruth A; Becker, Stefanie I; Lipp, Ottmar V

    2016-01-01

    Prior reports of preferential detection of emotional expressions in visual search have yielded inconsistent results, even for face stimuli that avoid obvious expression-related perceptual confounds. The current study investigated inconsistent reports of anger and happiness superiority effects using face stimuli drawn from the same database. Experiment 1 excluded procedural differences as a potential factor, replicating a happiness superiority effect in a procedure that previously yielded an anger superiority effect. Experiments 2a and 2b confirmed that image colour or poser gender did not account for prior inconsistent findings. Experiments 3a and 3b identified stimulus set as the critical variable, revealing happiness or anger superiority effects for two partially overlapping sets of face stimuli. The current results highlight the critical role of stimulus selection for the observation of happiness or anger superiority effects in visual search even for face stimuli that avoid obvious expression related perceptual confounds and are drawn from a single database.

  1. From foreground to background: how task-neutral context influences contextual cueing of visual search

    Directory of Open Access Journals (Sweden)

    Xuelian eZang

    2016-06-01

    Full Text Available Selective attention determines the effectiveness of implicit contextual learning (e.g., Jiang & Leung, 2005. Visual foreground-background segmentation, on the other hand, is a key process in the guidance of attention (Wolfe, 2003. In the present study, we examined the impact of foreground-background segmentation on contextual cueing of visual search in three experiments. A visual search display, consisting of distractor ‘L’s and a target ‘T’, was overlaid on a task-neutral cuboid on the same depth plane (Experiment 1, on stereoscopically separated depth planes (Experiment 2, or spread over the entire display on the same depth plane (Experiment 3. Half of the search displays contained repeated target-distractor arrangements, whereas the other half was always newly generated. The task-neutral cuboid was constant during an initial training session, but was either rotated by 90º or entirely removed in the subsequent test sessions. We found that the gains resulting from repeated presentation of display arrangements during training (i.e., contextual-cueing effects were diminished when the cuboid was changed or removed in Experiment 1, but remained intact in Experiments 2 and 3 when the cuboid was placed in a different depth plane, or when the items were randomly spread over the whole display but not on the edges of the cuboid. These findings suggest that foreground-background segmentation occurs prior to contextual learning, and only objects/arrangements that are grouped as foreground are learned over the course of repeated visual search.

  2. Effects of Anxiety on Anticipation and Visual Search in Dynamic, Time-Constrained Situations

    OpenAIRE

    Vater, C.; Roca, A.; Williams, A. M.

    2015-01-01

    We tested the predictions of Attentional Control Theory (ACT) by examining how anxiety affects visual search strategies, performance efficiency, and performance effectiveness using a dynamic, temporal-constrained anticipation task. Higher and lower skilled players viewed soccer situations under 2 task constraints (near vs. far situation) and were tested under high (HA) and low (LA) anxiety conditions. Response accuracy (effectiveness) and response time, perceived mental effort, and eye-moveme...

  3. I can see what you are saying: Auditory labels reduce visual search times.

    Science.gov (United States)

    Cho, Kit W

    2016-10-01

    The present study explored the self-directed-speech effect, the finding that relative to silent reading of a label (e.g., DOG), saying it aloud reduces visual search reaction times (RTs) for locating a target picture among distractors. Experiment 1 examined whether this effect is due to a confound in the differences in the number of cues in self-directed speech (two) vs. silent reading (one) and tested whether self-articulation is required for the effect. The results showed that self-articulation is not required and that merely hearing the auditory label reduces visual search RTs relative to silent reading. This finding also rules out the number of cues confound. Experiment 2 examined whether hearing an auditory label activates more prototypical features of the label's referent and whether the auditory-label benefit is moderated by the target's imagery concordance (the degree to which the target picture matches the mental picture that is activated by a written label for the target). When the target imagery concordance was high, RTs following the presentation of a high prototypicality picture or auditory cue were comparable and shorter than RTs following a visual label or low prototypicality picture cue. However, when the target imagery concordance was low, RTs following an auditory cue were shorter than the comparable RTs following the picture cues and visual-label cue. The results suggest that an auditory label activates both prototypical and atypical features of a concept and can facilitate visual search RTs even when compared to picture primes. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Expectation violations in sensorimotor sequences: shifting from LTM-based attentional selection to visual search.

    Science.gov (United States)

    Foerster, Rebecca M; Schneider, Werner X

    2015-03-01

    Long-term memory (LTM) delivers important control signals for attentional selection. LTM expectations have an important role in guiding the task-driven sequence of covert attention and gaze shifts, especially in well-practiced multistep sensorimotor actions. What happens when LTM expectations are disconfirmed? Does a sensory-based visual-search mode of attentional selection replace the LTM-based mode? What happens when prior LTM expectations become valid again? We investigated these questions in a computerized version of the number-connection test. Participants clicked on spatially distributed numbered shapes in ascending order while gaze was recorded. Sixty trials were performed with a constant spatial arrangement. In 20 consecutive trials, either numbers, shapes, both, or no features switched position. In 20 reversion trials, participants worked on the original arrangement. Only the sequence-affecting number switches elicited slower clicking, visual search-like scanning, and lower eye-hand synchrony. The effects were neither limited to the exchanged numbers nor to the corresponding actions. Thus, expectation violations in a well-learned sensorimotor sequence cause a regression from LTM-based attentional selection to visual search beyond deviant-related actions and locations. Effects lasted for several trials and reappeared during reversion. © 2015 New York Academy of Sciences.

  5. Fractal analysis of visual search activity for mass detection during mammographic screening.

    Science.gov (United States)

    Alamudun, Folami; Yoon, Hong-Jun; Hudson, Kathleen B; Morin-Ducote, Garnetta; Hammond, Tracy; Tourassi, Georgia D

    2017-03-01

    The objective of this study was to assess the complexity of human visual search activity during mammographic screening using fractal analysis and to investigate its relationship with case and reader characteristics. The study was performed for the task of mammographic screening with simultaneous viewing of four coordinated breast views as typically done in clinical practice. Eye-tracking data and diagnostic decisions collected for 100 mammographic cases (25 normal, 25 benign, 50 malignant) from 10 readers (three board certified radiologists and seven Radiology residents), formed the corpus for this study. The fractal dimension of the readers' visual scanning pattern was computed with the Minkowski-Bouligand box-counting method and used as a measure of gaze complexity. Individual factor and group-based interaction ANOVA analysis was performed to study the association between fractal dimension, case pathology, breast density, and reader experience level. The consistency of the observed trends depending on gaze data representation was also examined. Case pathology, breast density, reader experience level, and individual reader differences are all independent predictors of the complexity of visual scanning pattern when screening for breast cancer. No higher order effects were found to be significant. Fractal characterization of visual search behavior during mammographic screening is dependent on case properties and image reader characteristics. © 2017 American Association of Physicists in Medicine.

  6. Biometric recognition via texture features of eye movement trajectories in a visual searching task.

    Science.gov (United States)

    Li, Chunyong; Xue, Jiguo; Quan, Cheng; Yue, Jingwei; Zhang, Chenggang

    2018-01-01

    Biometric recognition technology based on eye-movement dynamics has been in development for more than ten years. Different visual tasks, feature extraction and feature recognition methods are proposed to improve the performance of eye movement biometric system. However, the correct identification and verification rates, especially in long-term experiments, as well as the effects of visual tasks and eye trackers' temporal and spatial resolution are still the foremost considerations in eye movement biometrics. With a focus on these issues, we proposed a new visual searching task for eye movement data collection and a new class of eye movement features for biometric recognition. In order to demonstrate the improvement of this visual searching task being used in eye movement biometrics, three other eye movement feature extraction methods were also tested on our eye movement datasets. Compared with the original results, all three methods yielded better results as expected. In addition, the biometric performance of these four feature extraction methods was also compared using the equal error rate (EER) and Rank-1 identification rate (Rank-1 IR), and the texture features introduced in this paper were ultimately shown to offer some advantages with regard to long-term stability and robustness over time and spatial precision. Finally, the results of different combinations of these methods with a score-level fusion method indicated that multi-biometric methods perform better in most cases.

  7. Alarm calls evoke a visual search image of a predator in birds.

    Science.gov (United States)

    Suzuki, Toshitaka N

    2018-02-13

    One of the core features of human speech is that words cause listeners to retrieve corresponding visual mental images. However, whether vocalizations similarly evoke mental images in animal communication systems is surprisingly unknown. Japanese tits ( Parus minor ) produce specific alarm calls when and only when encountering a predatory snake. Here, I show that simply hearing these calls causes tits to become more visually perceptive to objects resembling snakes. During playback of snake-specific alarm calls, tits approach a wooden stick being moved in a snake-like fashion. However, tits do not respond to the same stick when hearing other call types or if the stick's movement is dissimilar to that of a snake. Thus, before detecting a real snake, tits retrieve its visual image from snake-specific alarm calls and use this to search out snakes. This study provides evidence for a call-evoked visual search image in a nonhuman animal, offering a paradigm to explore the cognitive basis for animal vocal communication in the wild.

  8. Visual working memory supports the inhibition of previously processed information: evidence from preview search.

    Science.gov (United States)

    Al-Aidroos, Naseem; Emrich, Stephen M; Ferber, Susanne; Pratt, Jay

    2012-06-01

    In four experiments we assessed whether visual working memory (VWM) maintains a record of previously processed visual information, allowing old information to be inhibited, and new information to be prioritized. Specifically, we evaluated whether VWM contributes to the inhibition (i.e., visual marking) of previewed distractors in a preview search. We evaluated this proposal by testing three predictions. First, Experiments 1 and 2 demonstrate that preview inhibition is more effective when the number of previewed distractors is below VWM capacity than above; an effect that can only be observed at small preview set sizes (Experiment 2A) and when observers are allowed to move their eyes freely (Experiment 2B). Second, Experiment 3 shows that, when quantified as the number of inhibited distractors, the magnitude of the preview effect is stable across different search difficulties. Third, Experiment 4 demonstrates that individual differences in preview inhibition are correlated with individual differences in VWM capacity. These findings provide converging evidence that VWM supports the inhibition of previewed distractors. More generally, these findings demonstrate how VWM contributes to the efficiency of human visual information processing--VWM prioritizes new information by inhibiting old information from being reselected for attention.

  9. Allocation of cognitive resources in comparative visual search--individual and task dependent effects.

    Science.gov (United States)

    Hardiess, Gregor; Mallot, Hanspeter A

    2015-08-01

    Behaviors recruit multiple, mutually substitutable types of cognitive resources (e.g., data acquisition and memorization in comparative visual search), and the allocation of resources is performed in a cost-optimizing way. If costs associated with each type of resource are manipulated, e.g., by varying the complexity of the items studied or the visual separation of the arrays to be compared, according adjustments of resource allocation ("trade-offs") have been demonstrated. Using between-subject designs, previous studies showed overall trade-off behavior but neglected inter-individual variability of trade-off behavior. Here, we present a simplified paradigm for comparative visual search in which gaze-measurements are replaced by switching of a visual mask covering one stimulus array at a time. This paradigm allows for a full within-subject design. While overall trade-off curves could be reproduced, we found that each subject used a specific trade-off strategy which differ substantially between subjects. Still, task-dependent adjustment of resource allocation can be demonstrated but accounts only for a minor part of the overall trade-off range. In addition, we show that the individual trade-offs were adjusted in an unconscious and rather intuitive way, enabling a robust manifestation of the selected strategy space. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Modeling visual search using three-parameter probability functions in a hierarchical Bayesian framework.

    Science.gov (United States)

    Lin, Yi-Shin; Heinke, Dietmar; Humphreys, Glyn W

    2015-04-01

    In this study, we applied Bayesian-based distributional analyses to examine the shapes of response time (RT) distributions in three visual search paradigms, which varied in task difficulty. In further analyses we investigated two common observations in visual search-the effects of display size and of variations in search efficiency across different task conditions-following a design that had been used in previous studies (Palmer, Horowitz, Torralba, & Wolfe, Journal of Experimental Psychology: Human Perception and Performance, 37, 58-71, 2011; Wolfe, Palmer, & Horowitz, Vision Research, 50, 1304-1311, 2010) in which parameters of the response distributions were measured. Our study showed that the distributional parameters in an experimental condition can be reliably estimated by moderate sample sizes when Monte Carlo simulation techniques are applied. More importantly, by analyzing trial RTs, we were able to extract paradigm-dependent shape changes in the RT distributions that could be accounted for by using the EZ2 diffusion model. The study showed that Bayesian-based RT distribution analyses can provide an important means to investigate the underlying cognitive processes in search, including stimulus grouping and the bottom-up guidance of attention.

  11. Training shortens search times in children with visual impairment accompanied by nystagmus.

    Science.gov (United States)

    Huurneman, Bianca; Boonstra, F Nienke

    2014-01-01

    Perceptual learning (PL) can improve near visual acuity (NVA) in 4-9 year old children with visual impairment (VI). However, the mechanisms underlying improved NVA are unknown. The present study compares feature search and oculomotor measures in 4-9 year old children with VI accompanied by nystagmus (VI+nys [n = 33]) and children with normal vision (NV [n = 29]). Children in the VI+nys group were divided into three training groups: an experimental PL group, a control PL group, and a magnifier group. They were seen before (baseline) and after 6 weeks of training. Children with NV were only seen at baseline. The feature search task entailed finding a target E among distractor E's (pointing right) with element spacing varied in four steps: 0.04°, 0.5°, 1°, and 2°. At baseline, children with VI+nys showed longer search times, shorter fixation durations, and larger saccade amplitudes than children with NV. After training, all training groups showed shorter search times. Only the experimental PL group showed prolonged fixation duration after training at 0.5° and 2° spacing, p's respectively 0.033 and 0.021. Prolonged fixation duration was associated with reduced crowding and improved crowded NVA. One of the mechanisms underlying improved crowded NVA after PL in children with VI+nys seems to be prolonged fixation duration.

  12. Object Affordances Potentiate Responses but Do Not Guide Attentional Prioritization in a Visual Search Task

    Directory of Open Access Journals (Sweden)

    Yusuke eYamani

    2016-01-01

    Full Text Available Handled objects automatically activate afforded responses. The current experiment examined whether objects that afford a response are also prioritized for attentional processing in visual search. Targets were pictures of coffee cups with handles oriented either to the right or the left. Subjects searched for a target, a right-handled vs. left-handled coffee cup, among a varying number of distractor cups oriented in the opposite direction. Responses were faster when the direction of target handle and the key press were spatially matched than mismatched (stimulus-response compatibility effect, but object affordance did not moderate slopes of the search functions, indicating the absence of attentional prioritization effect. These findings imply that handled objects prime afforded responses without influencing attentional prioritization.

  13. White matter hyperintensities are associated with visual search behavior independent of generalized slowing in aging

    Science.gov (United States)

    Lockhart, Samuel N.; Roach, Alexandra E.; Luck, Steven J.; Geng, Joy; Beckett, Laurel; Carmichael, Owen; DeCarli, Charles

    2014-01-01

    A fundamental controversy is whether cognitive decline with advancing age can be entirely explained by decreased processing speed, or whether specific neural changes can elicit cognitive decline, independent of slowing. These hypotheses are anchored by studies of healthy older individuals where age is presumed the sole influence. Unfortunately, advancing age is also associated with asymptomatic brain white matter injury. We hypothesized that differences in white matter injury extent, manifest by MRI white matter hyperintensities (WMH), mediate differences in visual attentional control in healthy aging, beyond processing speed differences. We tested young and cognitively healthy older adults on search tasks indexing speed and attentional control. Increasing age was associated with generally slowed performance. WMH was also associated with slowed search times independent of processing speed differences. Consistent with evidence attributing reduced network connectivity to WMH, these results conclusively demonstrate that clinically silent white matter injury contributes to slower search performance indicative of compromised cognitive control, independent of generalized slowing of processing speed. PMID:24183716

  14. Sonification and visualization of predecisional information search: Identifying toolboxes in children.

    Science.gov (United States)

    Betsch, Tilmann; Wünsche, Kirsten; Großkopf, Armin; Schröder, Klara; Stenmans, Rachel

    2018-03-01

    Prior evidence has suggested that preschoolers and elementary schoolers search information largely with no systematic plan when making decisions in probabilistic environments. However, this finding might be due to the insensitivity of standard classification methods that assume a lack of variance in decision strategies for tasks of the same kind. Using a novel approach, we explore strategy variability in existing data that documented unsystematic searches in children (Betsch, Lehmann, Lindow, Lang, & Schoemann, 2016). By means of sonification and visualizations, we identified combinations of search patterns that children employed systematically. In contrast to adult controls, there was no dominating strategy in children. Rather, they used a limited number of strategies (toolboxes) and switched between them over a series of trials belonging to the same type of decision task. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  15. The role of the pulvinar in distractor processing and visual search.

    Science.gov (United States)

    Strumpf, Hendrick; Mangun, George R; Boehler, Carsten N; Stoppel, Christian; Schoenfeld, Mircea A; Heinze, Hans-Jochen; Hopf, Jens-Max

    2013-05-01

    The pulvinar nuclei of the thalamus are hypothesized to coordinate attentional selection in the visual cortex. Different models have, however, been proposed for the precise role of the pulvinar in attention. One proposal is that the pulvinar mediates shifts of spatial attention; a different proposal is that it serves the filtering of distractor information. At present, the relation between these possible operations and their relative importance in the pulvinar remains unresolved. We address this issue by contrasting these proposals in two fMRI experiments. We used a visual search paradigm that permitted us to dissociate neural activity reflecting shifts of attention from activity underlying distractor filtering. We find that distractor filtering, but not the operation of shifting attention, is associated with strong activity enhancements in dorsal and ventral regions of the pulvinar as well as in early visual cortex areas including the primary visual cortex. Our observations indicate that distractor filtering is the preponderant attentional operation subserved by the pulvinar, presumably mediated by a modulation of processing in visual areas where spatial resolution is sufficiently high to separate target from distractor input. Copyright © 2012 Wiley Periodicals, Inc.

  16. The effect of mood state on visual search times for detecting a target in noise: An application of smartphone technology.

    Science.gov (United States)

    Maekawa, Toru; Anderson, Stephen J; de Brecht, Matthew; Yamagishi, Noriko

    2018-01-01

    The study of visual perception has largely been completed without regard to the influence that an individual's emotional status may have on their performance in visual tasks. However, there is a growing body of evidence to suggest that mood may affect not only creative abilities and interpersonal skills but also the capacity to perform low-level cognitive tasks. Here, we sought to determine whether rudimentary visual search processes are similarly affected by emotion. Specifically, we examined whether an individual's perceived happiness level affects their ability to detect a target in noise. To do so, we employed pop-out and serial visual search paradigms, implemented using a novel smartphone application that allowed search times and self-rated levels of happiness to be recorded throughout each twenty-four-hour period for two weeks. This experience sampling protocol circumvented the need to alter mood artificially with laboratory-based induction methods. Using our smartphone application, we were able to replicate the classic visual search findings, whereby pop-out search times remained largely unaffected by the number of distractors whereas serial search times increased with increasing number of distractors. While pop-out search times were unaffected by happiness level, serial search times with the maximum numbers of distractors (n = 30) were significantly faster for high happiness levels than low happiness levels (p = 0.02). Our results demonstrate the utility of smartphone applications in assessing ecologically valid measures of human visual performance. We discuss the significance of our findings for the assessment of basic visual functions using search time measures, and for our ability to search effectively for targets in real world settings.

  17. Multisensory teamwork: using a tactile or an auditory display to exchange gaze information improves performance in joint visual search.

    Science.gov (United States)

    Wahn, Basil; Schwandt, Jessika; Krüger, Matti; Crafa, Daina; Nunnendorf, Vanessa; König, Peter

    2016-06-01

    In joint tasks, adjusting to the actions of others is critical for success. For joint visual search tasks, research has shown that when search partners visually receive information about each other's gaze, they use this information to adjust to each other's actions, resulting in faster search performance. The present study used a visual, a tactile and an auditory display, respectively, to provide search partners with information about each other's gaze. Results showed that search partners performed faster when the gaze information was received via a tactile or auditory display in comparison to receiving it via a visual display or receiving no gaze information. Findings demonstrate the effectiveness of tactile and auditory displays for receiving task-relevant information in joint tasks and are applicable to circumstances in which little or no visual information is available or the visual modality is already taxed with a demanding task such as air-traffic control. Practitioner Summary: The present study demonstrates that tactile and auditory displays are effective for receiving information about actions of others in joint tasks. Findings are either applicable to circumstances in which little or no visual information is available or when the visual modality is already taxed with a demanding task.

  18. Visual search behaviour in skeletal radiographs: a cross-speciality study

    International Nuclear Information System (INIS)

    Leong, J.J.H.; Nicolaou, M.; Emery, R.J.; Darzi, A.W.; Yang, G.-Z.

    2007-01-01

    Aim: To determine whether experience improves the consistency of visual search behaviour in fracture identification in plain radiographs, and the effect of specialization. Material and methods: Twenty-five observers consisting of consultant radiologists, consultant orthopaedic surgeons, orthopaedic specialist registrars, orthopaedic senior house officers, and accident and emergency senior house officers examined 33 skeletal radiographs (shoulder, hand, and knee). Eye movement data were collected using a Tobii 1750 eye tracker with levels of diagnostic confidence collected simultaneously. Kullback-Leibler (KL) divergence and Gaussian mixture model fitting of fixation distance-to-fracture were used to calculate the consistency and the relationship between discovery and reflective visual search phases among different observer groups. Results: Total time spent studying the radiograph was not significantly different between the groups. However, the expert groups had a higher number of true positives (p < 0.001) with less dwell time on the fracture site (p < 0.001) and smaller KL distance (r = 0.062, p < 0.001) between trials. The Gaussian mixture model revealed smaller mean squared error in the expert groups in hand radiographs (r 0.162, p = 0.07); however, the reverse was true in shoulder radiographs (r -0.287, p < 0.001). The relative duration of the reflective phase decreases as the confidence level increased (r = 0.266, p = 0.074). Conclusions: Expert search behaviour exhibited higher accuracy and consistency whilst using less time fixating on fracture sites. This strategy conforms to the discovery and reflective phases of the global-focal model, where the reflective search may be implicated in the cross-referencing and conspicuity of the target, as well as the level of decision-making process involved. The effect of specialization appears to change the search strategy more than the effect of the length of training

  19. Determinants of dwell time in visual search: similarity or perceptual difficulty?

    Science.gov (United States)

    Becker, Stefanie I

    2011-03-08

    The present study examined the factors that determine the dwell times in a visual search task, that is, the duration the gaze remains fixated on an object. It has been suggested that an item's similarity to the search target should be an important determiner of dwell times, because dwell times are taken to reflect the time needed to reject the item as a distractor, and such discriminations are supposed to be harder the more similar an item is to the search target. In line with this similarity view, a previous study shows that, in search for a target ring of thin line-width, dwell times on thin linewidth Landolt C's distractors were longer than dwell times on Landolt C's with thick or medium linewidth. However, dwell times may have been longer on thin Landolt C's because the thin line-width made it harder to detect whether the stimuli had a gap or not. Thus, it is an open question whether dwell times on thin line-width distractors were longer because they were similar to the target or because the perceptual decision was more difficult. The present study de-coupled similarity from perceptual difficulty, by measuring dwell times on thin, medium and thick line-width distractors when the target had thin, medium or thick line-width. The results showed that dwell times were longer on target-similar than target-dissimilar stimuli across all target conditions and regardless of the line-width. It is concluded that prior findings of longer dwell times on thin linewidth-distractors can clearly be attributed to target similarity. As will be discussed towards the end, the finding of similarity effects on dwell times has important implications for current theories of visual search and eye movement control.

  20. Effect of verbal instructions and image size on visual search strategies in basketball free throw shooting.

    Science.gov (United States)

    Al-Abood, Saleh A; Bennett, Simon J; Hernandez, Francisco Moreno; Ashford, Derek; Davids, Keith

    2002-03-01

    We assessed the effects on basketball free throw performance of two types of verbal directions with an external attentional focus. Novices (n = 16) were pre-tested on free throw performance and assigned to two groups of similar ability (n = 8 in each). Both groups received verbal instructions with an external focus on either movement dynamics (movement form) or movement effects (e.g. ball trajectory relative to basket). The participants also observed a skilled model performing the task on either a small or large screen monitor, to ascertain the effects of visual presentation mode on task performance. After observation of six videotaped trials, all participants were given a post-test. Visual search patterns were monitored during observation and cross-referenced with performance on the pre- and post-test. Group effects were noted for verbal instructions and image size on visual search strategies and free throw performance. The 'movement effects' group saw a significant improvement in outcome scores between the pre-test and post-test. These results supported evidence that this group spent more viewing time on information outside the body than the 'movement dynamics' group. Image size affected both groups equally with more fixations of shorter duration when viewing the small screen. The results support the benefits of instructions when observing a model with an external focus on movement effects, not dynamics.

  1. Neural Correlates of Changes in a Visual Search Task due to Cognitive Training in Seniors

    Directory of Open Access Journals (Sweden)

    Nele Wild-Wall

    2012-01-01

    Full Text Available This study aimed to elucidate the underlying neural sources of near transfer after a multidomain cognitive training in older participants in a visual search task. Participants were randomly assigned to a social control, a no-contact control and a training group, receiving a 4-month paper-pencil and PC-based trainer guided cognitive intervention. All participants were tested in a before and after session with a conjunction visual search task. Performance and event-related potentials (ERPs suggest that the cognitive training improved feature processing of the stimuli which was expressed in an increased rate of target detection compared to the control groups. This was paralleled by enhanced amplitudes of the frontal P2 in the ERP and by higher activation in lingual and parahippocampal brain areas which are discussed to support visual feature processing. Enhanced N1 and N2 potentials in the ERP for nontarget stimuli after cognitive training additionally suggest improved attention and subsequent processing of arrays which were not immediately recognized as targets. Possible test repetition effects were confined to processes of stimulus categorisation as suggested by the P3b potential. The results show neurocognitive plasticity in aging after a broad cognitive training and allow pinpointing the functional loci of effects induced by cognitive training.

  2. Contrasting gist-based and template-based guidance during real-world visual search.

    Science.gov (United States)

    Bahle, Brett; Matsukura, Michi; Hollingworth, Andrew

    2018-03-01

    Visual search through real-world scenes is guided both by a representation of target features and by knowledge of the sematic properties of the scene (derived from scene gist recognition). In 3 experiments, we compared the relative roles of these 2 sources of guidance. Participants searched for a target object in the presence of a critical distractor object. The color of the critical distractor either matched or mismatched (a) the color of an item maintained in visual working memory for a secondary task (Experiment 1), or (b) the color of the target, cued by a picture before search commenced (Experiments 2 and 3). Capture of gaze by a matching distractor served as an index of template guidance. There were 4 main findings: (a) The distractor match effect was observed from the first saccade on the scene, (b) it was independent of the availability of scene-level gist-based guidance, (c) it was independent of whether the distractor appeared in a plausible location for the target, and (d) it was preserved even when gist-based guidance was available before scene onset. Moreover, gist-based, semantic guidance of gaze to target-plausible regions of the scene was delayed relative to template-based guidance. These results suggest that feature-based template guidance is not limited to plausible scene regions after an initial, scene-level analysis. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  3. User-assisted visual search and tracking across distributed multi-camera networks

    Science.gov (United States)

    Raja, Yogesh; Gong, Shaogang; Xiang, Tao

    2011-11-01

    Human CCTV operators face several challenges in their task which can lead to missed events, people or associations, including: (a) data overload in large distributed multi-camera environments; (b) short attention span; (c) limited knowledge of what to look for; and (d) lack of access to non-visual contextual intelligence to aid search. Developing a system to aid human operators and alleviate such burdens requires addressing the problem of automatic re-identification of people across disjoint camera views, a matching task made difficult by factors such as lighting, viewpoint and pose changes and for which absolute scoring approaches are not best suited. Accordingly, we describe a distributed multi-camera tracking (MCT) system to visually aid human operators in associating people and objects effectively over multiple disjoint camera views in a large public space. The system comprises three key novel components: (1) relative measures of ranking rather than absolute scoring to learn the best features for matching; (2) multi-camera behaviour profiling as higher-level knowledge to reduce the search space and increase the chance of finding correct matches; and (3) human-assisted data mining to interactively guide search and in the process recover missing detections and discover previously unknown associations. We provide an extensive evaluation of the greater effectiveness of the system as compared to existing approaches on industry-standard i-LIDS multi-camera data.

  4. Visual search in ecological and non-ecological displays: evidence for a non-monotonic effect of complexity on performance.

    Science.gov (United States)

    Chassy, Philippe; Gobet, Fernand

    2013-01-01

    Considerable research has been carried out on visual search, with single or multiple targets. However, most studies have used artificial stimuli with low ecological validity. In addition, little is known about the effects of target complexity and expertise in visual search. Here, we investigate visual search in three conditions of complexity (detecting a king, detecting a check, and detecting a checkmate) with chess players of two levels of expertise (novices and club players). Results show that the influence of target complexity depends on level of structure of the visual display. Different functional relationships were found between artificial (random chess positions) and ecologically valid (game positions) stimuli: With artificial, but not with ecologically valid stimuli, a "pop out" effect was present when a target was visually more complex than distractors but could be captured by a memory chunk. This suggests that caution should be exercised when generalising from experiments using artificial stimuli with low ecological validity to real-life stimuli.

  5. Visual search in ecological and non-ecological displays: evidence for a non-monotonic effect of complexity on performance.

    Directory of Open Access Journals (Sweden)

    Philippe Chassy

    Full Text Available Considerable research has been carried out on visual search, with single or multiple targets. However, most studies have used artificial stimuli with low ecological validity. In addition, little is known about the effects of target complexity and expertise in visual search. Here, we investigate visual search in three conditions of complexity (detecting a king, detecting a check, and detecting a checkmate with chess players of two levels of expertise (novices and club players. Results show that the influence of target complexity depends on level of structure of the visual display. Different functional relationships were found between artificial (random chess positions and ecologically valid (game positions stimuli: With artificial, but not with ecologically valid stimuli, a "pop out" effect was present when a target was visually more complex than distractors but could be captured by a memory chunk. This suggests that caution should be exercised when generalising from experiments using artificial stimuli with low ecological validity to real-life stimuli.

  6. Visual search and attention in five-year-old very preterm/very low birth weight children.

    Science.gov (United States)

    Geldof, Christiaan J A; de Kieviet, Jorrit F; Dik, Marjolein; Kok, Joke H; van Wassenaer-Leemhuis, Aleid G; Oosterlaan, Jaap

    2013-12-01

    This study aimed to establish visual search performance and attention functioning in very preterm/very low birth weight (VP/VLBW) children using novel and well established measures, and to study their contribution to intellectual functioning. Visual search and attention network efficiency were assessed in 108 VP/VLBW children and 72 age matched term controls at 5.5 years corrected age. Visual search performance was investigated with a newly developed paradigm manipulating stimulus density and stimulus organization. Attention functioning was studied using the Attention Network Test (ANT). Intellectual functioning was measured by a short form of the Wechsler Preschool and Primary Scale of Intelligence. Data were analyzed using ANOVAs and multiple regression analyses. Visual search was less efficient in VP/VLBW children as compared to term controls, as indicated by increased search time (0.31 SD, p = .04) and increased error rate (0.36 SD, p = .02). In addition, VP/VLBW children demonstrated poorer executive attention as indicated by lower accuracy for the executive attention measure of the ANT (0.61 SD, p attention measures (0.13 SD, p = .42). Visual search time and error rate, and executive attention, collectively, accounted for 14% explained variance in full scale IQ (R(2) = .14, p attention. Visual attention dysfunctions contributed to intelligence, suggesting the opportunity to improve intellectual functioning by using interventions programs that may enhance attention capacities. © 2013.

  7. Hand movement deviations in a visual search task with cross modal cuing

    Directory of Open Access Journals (Sweden)

    Hürol Aslan

    2007-01-01

    Full Text Available The purpose of this study is to demonstrate the cross-modal effects of an auditory organization on a visual search task and to investigate the influence of the level of detail in instructions describing or hinting at the associations between auditory stimuli and the possible locations of a visual target. In addition to measuring the participants’ reaction times, we paid special attention to tracking the hand movements toward the target. According to the results, the auditory stimuli unassociated with the target locations slightly –but significantly- increased the deviation of the hand movement from the path leading to the target location. The increase in the deviation depended on the degree of association between auditory stimuli and target locations, albeit not on the level of detail in the instructions about the task.

  8. Examining wide-arc digital breast tomosynthesis: optimization using a visual-search model observer

    Science.gov (United States)

    Das, Mini; Liang, Zhihua; Gifford, Howard C.

    2015-03-01

    Mathematical model observers are expected to assist in preclinical optimization of image acquisition and reconstruction parameters. A clinically realistic and robust model observer platform could help in multiparameter optimizations without requiring frequent human-observer validations. We are developing search-capable visual-search (VS) model observers with this potential. In this work, we present initial results on optimization of DBT scan angle and the number of projection views for low-contrast mass detection. Comparison with human-observer results shows very good agreement. These results point towards the benefits of using relatively wider arcs and low projection angles per arc degree for improved mass detection. These results are particularly interesting considering that the FDA-approved DBT systems like Hologic Selenia Dimensions uses a narrow (15-degree) acquisition arc and one projection per arc degree.

  9. Gaze in Visual Search Is Guided More Efficiently by Positive Cues than by Negative Cues.

    Science.gov (United States)

    Kugler, Günter; 't Hart, Bernard Marius; Kohlbecher, Stefan; Einhäuser, Wolfgang; Schneider, Erich

    2015-01-01

    Visual search can be accelerated when properties of the target are known. Such knowledge allows the searcher to direct attention to items sharing these properties. Recent work indicates that information about properties of non-targets (i.e., negative cues) can also guide search. In the present study, we examine whether negative cues lead to different search behavior compared to positive cues. We asked observers to search for a target defined by a certain shape singleton (broken line among solid lines). Each line was embedded in a colored disk. In "positive cue" blocks, participants were informed about possible colors of the target item. In "negative cue" blocks, the participants were informed about colors that could not contain the target. Search displays were designed such that with both the positive and negative cues, the same number of items could potentially contain the broken line ("relevant items"). Thus, both cues were equally informative. We measured response times and eye movements. Participants exhibited longer response times when provided with negative cues compared to positive cues. Although negative cues did guide the eyes to relevant items, there were marked differences in eye movements. Negative cues resulted in smaller proportions of fixations on relevant items, longer duration of fixations and in higher rates of fixations per item as compared to positive cues. The effectiveness of both cue types, as measured by fixations on relevant items, increased over the course of each search. In sum, a negative color cue can guide attention to relevant items, but it is less efficient than a positive cue of the same informational value.

  10. The interplay of attention and consciousness in visual search, attentional blink and working memory consolidation.

    Science.gov (United States)

    Raffone, Antonino; Srinivasan, Narayanan; van Leeuwen, Cees

    2014-05-05

    Despite the acknowledged relationship between consciousness and attention, theories of the two have mostly been developed separately. Moreover, these theories have independently attempted to explain phenomena in which both are likely to interact, such as the attentional blink (AB) and working memory (WM) consolidation. Here, we make an effort to bridge the gap between, on the one hand, a theory of consciousness based on the notion of global workspace (GW) and, on the other, a synthesis of theories of visual attention. We offer a theory of attention and consciousness (TAC) that provides a unified neurocognitive account of several phenomena associated with visual search, AB and WM consolidation. TAC assumes multiple processing stages between early visual representation and conscious access, and extends the dynamics of the global neuronal workspace model to a visual attentional workspace (VAW). The VAW is controlled by executive routers, higher-order representations of executive operations in the GW, without the need for explicit saliency or priority maps. TAC leads to newly proposed mechanisms for illusory conjunctions, AB, inattentional blindness and WM capacity, and suggests neural correlates of phenomenal consciousness. Finally, the theory reconciles the all-or-none and graded perspectives on conscious representation.

  11. Performance of brain-damaged, schizophrenic, and normal subjects on a visual searching task.

    Science.gov (United States)

    Goldstein, G; Kyc, F

    1978-06-01

    Goldstein, Rennick, Welch, and Shelly (1973) reported on a visual searching task that generated 94.1% correct classifications when comparing brain-damaged and normal subjects, and 79.4% correct classifications when comparing brain-damaged and psychiatric patients. In the present study, representing a partial cross-validation with some modification of the test procedure, comparisons were made between brain-damaged and schizophrenic, and brain-damaged and normal subjects. There were 92.5% correct classifications for the brain-damaged vs normal comparison, and 82.5% correct classifications for the brain-damaged vs schizophrenic comparison.

  12. Change They Can't Find: Change Blindness in Chimpanzees during a Visual Search Task

    Directory of Open Access Journals (Sweden)

    Masaki Tomonaga

    2015-04-01

    Full Text Available Although considerable advances have been made in the study of change blindness in humans, research regarding change blindness in nonhuman animals has been rare thus far. Indeed, we do not know whether chimpanzees, our closest evolutionary relatives, experience difficulty detecting changes in a stimulus when presentations are separated by blank displays. This study demonstrated that chimpanzees showed severe difficulties in detecting changes in a flicker-type visual search task, and these results are discussed in relation to the adaptive significance of change detection (e.g. the relationship between change blindness and vigilance behaviour.

  13. Adult age differences in visual search from perception to response: Evidence from event-related potentials

    DEFF Research Database (Denmark)

    Wiegand, Iris

    Attentional changes play a major role in age-related behavioral slowing, however, the specific aspects of attention that contribute to this decrement are not clearly defined. To these aims, we combined response times with lateralized ERPs of younger and older adults during a visual compound search...... at multiple stages from perception to response. Furthermore, we explored the implicit influence of recently encountered information in terms of intertrial effects. ERPs could disentangle that, while automatic processes of perceptual-dimension priming and response priming across trials were preserved, older...

  14. Hippocampal gamma-band Synchrony and pupillary responses index memory during visual search.

    Science.gov (United States)

    Montefusco-Siegmund, Rodrigo; Leonard, Timothy K; Hoffman, Kari L

    2017-04-01

    Memory for scenes is supported by the hippocampus, among other interconnected structures, but the neural mechanisms related to this process are not well understood. To assess the role of the hippocampus in memory-guided scene search, we recorded local field potentials and multiunit activity from the hippocampus of macaques as they performed goal-directed search tasks using natural scenes. We additionally measured pupil size during scene presentation, which in humans is modulated by recognition memory. We found that both pupil dilation and search efficiency accompanied scene repetition, thereby indicating memory for scenes. Neural correlates included a brief increase in hippocampal multiunit activity and a sustained synchronization of unit activity to gamma band oscillations (50-70 Hz). The repetition effects on hippocampal gamma synchronization occurred when pupils were most dilated, suggesting an interaction between aroused, attentive processing and hippocampal correlates of recognition memory. These results suggest that the hippocampus may support memory-guided visual search through enhanced local gamma synchrony. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. Reaction times in visual search can be explained by a simple model of neural synchronization.

    Science.gov (United States)

    Kazanovich, Yakov; Borisyuk, Roman

    2017-03-01

    We present an oscillatory neural network model that can account for reaction times in visual search experiments. The model consists of a central oscillator that represents the central executive of the attention system and a number of peripheral oscillators that represent objects in the display. The oscillators are described as generalized Kuramoto type oscillators with adapted parameters. An object is considered as being included in the focus of attention if the oscillator associated with this object is in-phase with the central oscillator. The probability for an object to be included in the focus of attention is determined by its saliency that is described in formal terms as the strength of the connection from the peripheral oscillator to the central oscillator. By computer simulations it is shown that the model can reproduce reaction times in visual search tasks of various complexities. The dependence of the reaction time on the number of items in the display is represented by linear functions of different steepness which is in agreement with biological evidence. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Putting attention in the spotlight: The influence of APOE genotype on visual search in mid adulthood.

    Science.gov (United States)

    Lancaster, Claire; Forster, Sophie; Tabet, Naji; Rusted, Jennifer

    2017-09-15

    The Apolipoprotein E e4 allele is associated with greater cognitive decline with age, yet effects of this gene are also observed earlier in the lifespan. This research explores genotype differences (e2, e3, e4) in the allocation of visuospatial attention in mid-adulthood. Sixty-six volunteers, aged 45-55 years, completed two paradigms probing the active selection of information at the focus of attention (a dynamic scaling task) and perceptual capacity differences. Two methods of statistical comparison (parametric statistics, Bayesian inference) found no significant difference between e4 carriers and the homozygous e3 group on either the dynamic scaling or perceptual load task. E2 carriers, however, demonstrated less efficient visual search performance on the dynamic scaling task. The lack of an e4 difference in visuospatial attention, despite previous suggestion in the literature of genotype effects, indicates that select attentional processes are intact in e4 carriers in mid-adulthood. The association of e2 genotype with slower visual search performance complicates the premised protective effects of this allele in cognitive ageing. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Simultaneous priming along multiple feature dimensions in a visual search task.

    Science.gov (United States)

    Kristjánsson, Arni

    2006-08-01

    What we have recently seen generally has a large effect on how we consequently perceive our visual environment. Such priming effects play a surprisingly large role in visual search tasks, for example. It is unclear, however, whether different features of an object show independent but simultaneous priming. For example, if the color and orientation of a target item are the same as on a previous trial, is performance better than if only one of those features is repeated? In other words this paper presents an attempt at assessing the capacity of priming for different feature dimensions. Observers searched for a three featured object (a gabor patch that was either redscale or greenscale, oriented either to the left or right of vertical and of high or low spatial frequency) among distractors with different values along these feature dimensions. Which feature was the target defining feature; which was the response defining feature and which was the irrelevant feature, was varied between the different experiments. Task relevant features (target defining, or response defining) always resulted in priming effects, while when spatial frequency or orientation were task irrelevant neither resulted in priming, but color always did, even when task irrelevant. Further experiments showed that priming from spatial frequency and orientation could occur when they were task irrelevant but only when the other feature of the two was kept constant across all display items. The results show that simultaneous priming for different features can occur simultaneously, but also that task relevance has a strong modulatory effect on the priming.

  18. Autism spectrum disorder, but not amygdala lesions, impairs social attention in visual search

    Science.gov (United States)

    Wang, Shuo; Xu, Juan; Jiang, Ming; Zhao, Qi; Hurlemann, Rene; Adolphs, Ralph

    2015-01-01

    People with autism spectrum disorders (ASD) have pervasive impairments in social interactions, a diagnostic component that may have its roots in atypical social motivation and attention. One of the brain structures implicated in the social abnormalities seen in ASD is the amygdala. To further characterize the impairment of people with ASD in social attention, and to explore the possible role of the amygdala, we employed a series of visual search tasks with both social (faces and people with different postures, emotions, ages, and genders) and non-social stimuli (e.g., electronics, food, and utensils). We first conducted trial-wise analyses of fixation properties and elucidated visual search mechanisms. We found that an attentional mechanism of initial orientation could explain the detection advantage of non-social targets. We then zoomed into fixation-wise analyses. We defined target-relevant effects as the difference in the percentage of fixations that fell on target-congruent vs. target-incongruent items in the array. In Experiment 1, we tested 8 high-functioning adults with ASD, 3 adults with focal bilateral amygdala lesions, and 19 controls. Controls rapidly oriented to target-congruent items and showed a strong and sustained preference for fixating them. Strikingly, people with ASD oriented significantly less and more slowly to target-congruent items, an attentional deficit especially with social targets. By contrast, patients with amygdala lesions performed indistinguishably from controls. In Experiment 2, we recruited a different sample of 13 people with ASD and 8 healthy controls, and tested them on the same search arrays but with all array items equalized for low-level saliency. The results replicated those of Experiment 1. In Experiment 3, we recruited 13 people with ASD, 8 healthy controls, 3 amygdala lesion patients and another group of 11 controls and tested them on a simpler array. Here our group effect for ASD strongly diminished and all four subject

  19. Visual search strategies of soccer players executing a power vs. placement penalty kick.

    Directory of Open Access Journals (Sweden)

    Matthew A Timmis

    Full Text Available When taking a soccer penalty kick, there are two distinct kicking techniques that can be adopted; a 'power' penalty or a 'placement' penalty. The current study investigated how the type of penalty kick being taken affected the kicker's visual search strategy and where the ball hit the goal (end ball location.Wearing a portable eye tracker, 12 university footballers executed 2 power and placement penalty kicks, indoors, both with and without the presence of a goalkeeper. Video cameras were used to determine initial ball velocity and end ball location.When taking the power penalty, the football was kicked significantly harder and more centrally in the goal compared to the placement penalty. During the power penalty, players fixated on the football for longer and more often at the goalkeeper (and by implication the middle of the goal, whereas in the placement penalty, fixated longer at the goal, specifically the edges. Findings remained consistent irrespective of goalkeeper presence.Findings indicate differences in visual search strategy and end ball location as a function of type of penalty kick. When taking the placement penalty, players fixated and kicked the football to the edges of the goal in an attempt to direct the ball to an area that the goalkeeper would have difficulty reaching and saving. Fixating significantly longer on the football when taking the power compared to placement penalty indicates a greater importance of obtaining visual information from the football. This can be attributed to ensuring accurate foot-to-ball contact and subsequent generation of ball velocity. Aligning gaze and kicking the football centrally in the goal when executing the power compared to placement penalty may have been a strategy to reduce the risk of kicking wide of the goal altogether.

  20. [Analysis of the eye movement patterns in visual search tasks: effect of familiarity and stimulus features].

    Science.gov (United States)

    Macedo, Elizeu Coutinho de; Covre, Priscila; Orsati, Fernanda Tebexreni; Oliveira, Maira Okada de; Schwartzman, José Salomão

    2007-01-01

    To analyze eye movements in asymmetric visual search using the task of normal and mirrored position letters. To evaluate the effect of familiarity and stimulus features. Eighty-three university students with normal or corrected-to-normal vision were asked to search for a letter in inverted position to the letters in a group of either normal or mirrored letters. Four types of letters were used (Z, N, E and G) and the eye movements were tracked by a specialized computer-based system (eyetracking). The analyzed measurements were: reaction time, fixation number and duration, saccade distance and duration. All measures varied with the type of letter. Reaction time, fixation number, and saccade distance were higher when the task was to find the normal letter in a group of mirrored letters. In this condition, fixation duration was smaller. Interaction was found between familiarity and the type of letter for the reaction time, fixation number and duration. The reaction time and fixation number increased together with the stimulus complexity, with a greater increase for the normal letter target. Fixation duration, however, decreased with the complexity of the stimuli and the search condition. Finding a mirrored letter among normal letters proved to be easier than the contrary. The letter type also affected the performance. When the context is formed of unfamiliar complex stimuli, the fixation duration is shorter, indicating a narrower span for visual processing. Therefore, a greater number of fixations with shorter duration are needed for the unfamiliar context while less fixations with greater duration are needed for the familiar context.

  1. Priming of pop-out on multiple time scales during visual search.

    Science.gov (United States)

    Brascamp, Jan W; Pels, Elmar; Kristjánsson, Arni

    2011-09-01

    When target-color repeats in pop-out visual search performance is faster than otherwise. While various characteristics of such priming of pop-out (PoP) are well known, relatively little is known about the temporal character of the memory traces underlying the effect. Recent findings on the perception of ambiguous stimuli show that the percept at any given moment is affected by perception over a long period, as well as by immediately preceding percepts. Intrigued by the existence of various parallels between this perceptual priming phenomenon and PoP, we here investigate whether similar multiplicity in timescales is seen for PoP. We contrasted long-term PoP build-up of a particular target color against shorter-term build-up for a different color. The priming effects from the two colors indeed reflect memory traces at different timescales: long-term priming build-up results in a more gradual decay than brief buildup, which is followed by faster decay. This is clearly demonstrated in Experiment 2 where sustained repetition of one target color is followed by a few repetitions of a second color. Following such a sequence, priming is initially stronger for the second target color, which was primed most recently; however, as more time passes longer-term priming starts to dominate, resulting in better search performance for the first color later on. Our results suggest that priming effects in visual search contain both transient and more sustained components. Similarities between the time courses of attentional priming and perception of ambiguous stimuli are striking and suggest compelling avenues of further research into the relation between the two effects. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Micro and regular saccades across the lifespan during a visual search of "Where's Waldo" puzzles.

    Science.gov (United States)

    Port, Nicholas L; Trimberger, Jane; Hitzeman, Steve; Redick, Bryan; Beckerman, Stephen

    2016-01-01

    Despite the fact that different aspects of visual-motor control mature at different rates and aging is associated with declines in both sensory and motor function, little is known about the relationship between microsaccades and either development or aging. Using a sample of 343 individuals ranging in age from 4 to 66 and a task that has been shown to elicit a high frequency of microsaccades (solving Where's Waldo puzzles), we explored microsaccade frequency and kinematics (main sequence curves) as a function of age. Taking advantage of the large size of our dataset (183,893 saccades), we also address (a) the saccade amplitude limit at which video eye trackers are able to accurately measure microsaccades and (b) the degree and consistency of saccade kinematics at varying amplitudes and directions. Using a modification of the Engbert-Mergenthaler saccade detector, we found that even the smallest amplitude movements (0.25-0.5°) demonstrate basic saccade kinematics. With regard to development and aging, both microsaccade and regular saccade frequency exhibited a very small increase across the life span. Visual search ability, as per many other aspects of visual performance, exhibited a U-shaped function over the lifespan. Finally, both large horizontal and moderate vertical directional biases were detected for all saccade sizes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Multichannel spatio-temporal topographic processing for visual search and navigation

    Science.gov (United States)

    Szatmari, Istvan; Balya, David; Timar, Gergely; Rekeczky, Csaba; Roska, Tamas

    2003-04-01

    In this paper a biologically motivated image flow processing mechanism is presented for visual exploration systems. The intention of this multi-channel topographic approach was to produce decision maps for salient feature localization and identification. As a unique biological study has recently confirmed mammalian visual systems process the world through a set of separate parallel channels and these representations are embodied in a stack of 'strata' in the retina. Beyond reflecting the biological motivations our main goal was to create an efficient algorithmic framework for real-life visual search and navigation experiments. In the course of this design the retinotopic processing scheme is embedded in an analogic Cellular Neural Network (CNN) algorithm where image flow is analyzed by temporal, spatial and spatio-temporal filters. The output of these sub-channels is then combined in a programmable configuration to form the new channel responses. In the core of the algorithm crisp or fuzzy logic strategies define the global channel interaction and result in a unique binary image flow. This processing mechanism of the algorithmic framework and the hardware architecture of the system are presented along with experimental ACE4k CNN chip results for several video flows recorded in flying vehicles.

  4. iPixel: a visual content-based and semantic search engine for retrieving digitized mammograms by using collective intelligence.

    Science.gov (United States)

    Alor-Hernández, Giner; Pérez-Gallardo, Yuliana; Posada-Gómez, Rubén; Cortes-Robles, Guillermo; Rodríguez-González, Alejandro; Aguilar-Laserre, Alberto A

    2012-09-01

    Nowadays, traditional search engines such as Google, Yahoo and Bing facilitate the retrieval of information in the format of images, but the results are not always useful for the users. This is mainly due to two problems: (1) the semantic keywords are not taken into consideration and (2) it is not always possible to establish a query using the image features. This issue has been covered in different domains in order to develop content-based image retrieval (CBIR) systems. The expert community has focussed their attention on the healthcare domain, where a lot of visual information for medical analysis is available. This paper provides a solution called iPixel Visual Search Engine, which involves semantics and content issues in order to search for digitized mammograms. iPixel offers the possibility of retrieving mammogram features using collective intelligence and implementing a CBIR algorithm. Our proposal compares not only features with similar semantic meaning, but also visual features. In this sense, the comparisons are made in different ways: by the number of regions per image, by maximum and minimum size of regions per image and by average intensity level of each region. iPixel Visual Search Engine supports the medical community in differential diagnoses related to the diseases of the breast. The iPixel Visual Search Engine has been validated by experts in the healthcare domain, such as radiologists, in addition to experts in digital image analysis.

  5. Monitoring Processes in Visual Search Enhanced by Professional Experience: The Case of Orange Quality-Control Workers

    Directory of Open Access Journals (Sweden)

    Antonino Visalli

    2018-02-01

    Full Text Available Visual search tasks have often been used to investigate how cognitive processes change with expertise. Several studies have shown visual experts' advantages in detecting objects related to their expertise. Here, we tried to extend these findings by investigating whether professional search experience could boost top-down monitoring processes involved in visual search, independently of advantages specific to objects of expertise. To this aim, we recruited a group of quality-control workers employed in citrus farms. Given the specific features of this type of job, we expected that the extensive employment of monitoring mechanisms during orange selection could enhance these mechanisms even in search situations in which orange-related expertise is not suitable. To test this hypothesis, we compared performance of our experimental group and of a well-matched control group on a computerized visual search task. In one block the target was an orange (expertise target while in the other block the target was a Smurfette doll (neutral target. The a priori hypothesis was to find an advantage for quality-controllers in those situations in which monitoring was especially involved, that is, when deciding the presence/absence of the target required a more extensive inspection of the search array. Results were consistent with our hypothesis. Quality-controllers were faster in those conditions that extensively required monitoring processes, specifically, the Smurfette-present and both target-absent conditions. No differences emerged in the orange-present condition, which resulted to mainly rely on bottom-up processes. These results suggest that top-down processes in visual search can be enhanced through immersive real-life experience beyond visual expertise advantages.

  6. Monitoring Processes in Visual Search Enhanced by Professional Experience: The Case of Orange Quality-Control Workers.

    Science.gov (United States)

    Visalli, Antonino; Vallesi, Antonino

    2018-01-01

    Visual search tasks have often been used to investigate how cognitive processes change with expertise. Several studies have shown visual experts' advantages in detecting objects related to their expertise. Here, we tried to extend these findings by investigating whether professional search experience could boost top-down monitoring processes involved in visual search, independently of advantages specific to objects of expertise. To this aim, we recruited a group of quality-control workers employed in citrus farms. Given the specific features of this type of job, we expected that the extensive employment of monitoring mechanisms during orange selection could enhance these mechanisms even in search situations in which orange-related expertise is not suitable. To test this hypothesis, we compared performance of our experimental group and of a well-matched control group on a computerized visual search task. In one block the target was an orange (expertise target) while in the other block the target was a Smurfette doll (neutral target). The a priori hypothesis was to find an advantage for quality-controllers in those situations in which monitoring was especially involved, that is, when deciding the presence/absence of the target required a more extensive inspection of the search array. Results were consistent with our hypothesis. Quality-controllers were faster in those conditions that extensively required monitoring processes, specifically, the Smurfette-present and both target-absent conditions. No differences emerged in the orange-present condition, which resulted to mainly rely on bottom-up processes. These results suggest that top-down processes in visual search can be enhanced through immersive real-life experience beyond visual expertise advantages.

  7. The effect of computer-aided detection markers on visual search and reader performance during concurrent reading of CT colonography

    International Nuclear Information System (INIS)

    Helbren, Emma; Taylor, Stuart A.; Fanshawe, Thomas R.; Mallett, Susan; Phillips, Peter; Boone, Darren; Gale, Alastair; Altman, Douglas G.; Manning, David; Halligan, Steve

    2015-01-01

    We aimed to identify the effect of computer-aided detection (CAD) on visual search and performance in CT Colonography (CTC) of inexperienced and experienced readers. Fifteen endoluminal CTC examinations were recorded, each with one polyp, and two videos were generated, one with and one without a CAD mark. Forty-two readers (17 experienced, 25 inexperienced) interpreted the videos during infrared visual search recording. CAD markers and polyps were treated as regions of interest in data processing. This multi-reader, multi-case study was analysed using multilevel modelling. CAD drew readers' attention to polyps faster, accelerating identification times: median 'time to first pursuit' was 0.48 s (IQR 0.27 to 0.87 s) with CAD, versus 0.58 s (IQR 0.35 to 1.06 s) without. For inexperienced readers, CAD also held visual attention for longer. All visual search metrics used to assess visual gaze behaviour demonstrated statistically significant differences when ''with'' and ''without'' CAD were compared. A significant increase in the number of correct polyp identifications across all readers was seen with CAD (74 % without CAD, 87 % with CAD; p < 0.001). CAD significantly alters visual search and polyp identification in readers viewing three-dimensional endoluminal CTC. For polyp and CAD marker pursuit times, CAD generally exerted a larger effect on inexperienced readers. (orig.)

  8. The effect of computer-aided detection markers on visual search and reader performance during concurrent reading of CT colonography

    Energy Technology Data Exchange (ETDEWEB)

    Helbren, Emma; Taylor, Stuart A. [University College London, Centre for Medical Imaging, London (United Kingdom); Fanshawe, Thomas R.; Mallett, Susan [University of Oxford, Nuffield Department of Primary Care Health Sciences, Oxford (United Kingdom); Phillips, Peter [University of Cumbria, Health and Medical Sciences Group, Lancaster (United Kingdom); Boone, Darren [Colchester Hospital University NHS Foundation Trust and Anglia University, Colchester (United Kingdom); Gale, Alastair [Loughborough University, Applied Vision Research Centre, Loughborough (United Kingdom); Altman, Douglas G. [University of Oxford, Centre for Statistics in Medicine, Oxford (United Kingdom); Manning, David [Lancaster University, Lancaster Medical School, Faculty of Health and Medicine, Lancaster (United Kingdom); Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); University College Hospital, Gastrointestinal Radiology, University College London, Centre for Medical Imaging, Podium Level 2, London, NW1 2BU (United Kingdom)

    2015-06-01

    We aimed to identify the effect of computer-aided detection (CAD) on visual search and performance in CT Colonography (CTC) of inexperienced and experienced readers. Fifteen endoluminal CTC examinations were recorded, each with one polyp, and two videos were generated, one with and one without a CAD mark. Forty-two readers (17 experienced, 25 inexperienced) interpreted the videos during infrared visual search recording. CAD markers and polyps were treated as regions of interest in data processing. This multi-reader, multi-case study was analysed using multilevel modelling. CAD drew readers' attention to polyps faster, accelerating identification times: median 'time to first pursuit' was 0.48 s (IQR 0.27 to 0.87 s) with CAD, versus 0.58 s (IQR 0.35 to 1.06 s) without. For inexperienced readers, CAD also held visual attention for longer. All visual search metrics used to assess visual gaze behaviour demonstrated statistically significant differences when ''with'' and ''without'' CAD were compared. A significant increase in the number of correct polyp identifications across all readers was seen with CAD (74 % without CAD, 87 % with CAD; p < 0.001). CAD significantly alters visual search and polyp identification in readers viewing three-dimensional endoluminal CTC. For polyp and CAD marker pursuit times, CAD generally exerted a larger effect on inexperienced readers. (orig.)

  9. Estimation of mental effort in learning visual search by measuring pupil response.

    Directory of Open Access Journals (Sweden)

    Tatsuto Takeuchi

    Full Text Available Perceptual learning refers to the improvement of perceptual sensitivity and performance with training. In this study, we examined whether learning is accompanied by a release from mental effort on the task, leading to automatization of the learned task. For this purpose, we had subjects conduct a visual search for a target, defined by a combination of orientation and spatial frequency, while we monitored their pupil size. It is well known that pupil size reflects the strength of mental effort invested in a task. We found that pupil size increased rapidly as the learning proceeded in the early phase of training and decreased at the later phase to a level half of its maximum value. This result does not support the simple automatization hypothesis. Instead, it suggests that the mental effort and behavioral performance reflect different aspects of perceptual learning. Further, mental effort would be continued to be invested to maintain good performance at a later stage of training.

  10. HSI-Find: A Visualization and Search Service for Terascale Spectral Image Catalogs

    Science.gov (United States)

    Thompson, D. R.; Smith, A. T.; Castano, R.; Palmer, E. E.; Xing, Z.

    2013-12-01

    Imaging spectrometers are remote sensing instruments commonly deployed on aircraft and spacecraft. They provide surface reflectance in hundreds of wavelength channels, creating data cubes known as hyperspecrtral images. They provide rich compositional information making them powerful tools for planetary and terrestrial science. These data products can be challenging to interpret because they contain datapoints numbering in the thousands (Dawn VIR) or millions (AVIRIS-C). Cross-image studies or exploratory searches involving more than one scene are rare; data volumes are often tens of GB per image and typical consumer-grade computers cannot store more than a handful of images in RAM. Visualizing the information in a single scene is challenging since the human eye can only distinguish three color channels out of the hundreds available. To date, analysis has been performed mostly on single images using purpose-built software tools that require extensive training and commercial licenses. The HSIFind software suite provides a scalable distributed solution to the problem of visualizing and searching large catalogs of spectral image data. It consists of a RESTful web service that communicates to a javascript-based browser client. The software provides basic visualization through an intuitive visual interface, allowing users with minimal training to explore the images or view selected spectra. Users can accumulate a library of spectra from one or more images and use these to search for similar materials. The result appears as an intensity map showing the extent of a spectral feature in a scene. Continuum removal can isolate diagnostic absorption features. The server-side mapping algorithm uses an efficient matched filter algorithm that can process a megapixel image cube in just a few seconds. This enables real-time interaction, leading to a new way of interacting with the data: the user can launch a search with a single mouse click and see the resulting map in seconds

  11. Simultaneous tDCS-fMRI Identifies Resting State Networks Correlated with Visual Search Enhancement

    Directory of Open Access Journals (Sweden)

    Daniel eCallan

    2016-03-01

    Full Text Available This study uses simultaneous transcranial direct current stimulation tDCS and fMRI to investigate tDCS modulation of resting state activity and connectivity that underlies enhancement in behavioral performance. The experiment consisted of three sessions within the fMRI scanner in which participants conducted a visual search task: Session 1. Pre-training (no performance feedback, Session 2. Training (performance feedback given, Session 3. Post-training (no performance feedback. Resting state activity was recorded during the last five minutes of each session. During the 2nd session one group of participants underwent 1mA tDCS stimulation and another underwent sham stimulation over the right posterior parietal cortex. Resting state spontaneous activity, as measured by fractional amplitude of low frequency fluctuations, for session 2 showed significant differences between the tDCS stim and sham groups in the precuneus. Resting state functional connectivity from the precuneus to the substantia nigra, a subcortical dopaminergic region, was found to correlate with future improvement in visual search task performance for the stim over the sham group during active stimulation in session 2. The after-effect of stimulation on resting state functional connectivity was measured following a post-training experimental session (session 3. The left cerebellum Lobule VIIa Crus I showed performance related enhancement in resting state functional connectivity for the tDCS stim over the sham group. The ability to determine the relationship that the relative strength of resting state functional connectivity for an individual undergoing tDCS has on future enhancement in behavioral performance has wide ranging implications for neuroergonomic as well as therapeutic, and rehabilitative applications.

  12. Individual Differences in Search and Monitoring for Color Targets in Dynamic Visual Displays.

    Science.gov (United States)

    Muhl-Richardson, Alex; Godwin, Hayward J; Garner, Matthew; Hadwin, Julie A; Liversedge, Simon P; Donnelly, Nick

    2018-02-01

    Many real-world tasks now involve monitoring visual representations of data that change dynamically over time. Monitoring dynamically changing displays for the onset of targets can be done in two ways: detecting targets directly, post-onset, or predicting their onset from the prior state of distractors. In the present study, participants' eye movements were measured as they monitored arrays of 108 colored squares whose colors changed systematically over time. Across three experiments, the data show that participants detected the onset of targets both directly and predictively. Experiments 1 and 2 showed that predictive detection was only possible when supported by sequential color changes that followed a scale ordered in color space. Experiment 3 included measures of individual differences in working memory capacity (WMC) and anxious affect and a manipulation of target prevalence in the search task. It found that predictive monitoring for targets, and decisions about target onsets, were influenced by interactions between individual differences in verbal and spatial WMC and intolerance of uncertainty, a characteristic that reflects worry about uncertain future events. The results have implications for the selection of individuals tasked with monitoring dynamic visual displays for target onsets. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  13. Investigation of attentional bias in obsessive compulsive disorder with and without depression in visual search.

    Directory of Open Access Journals (Sweden)

    Sharon Morein-Zamir

    Full Text Available Whether Obsessive Compulsive Disorder (OCD is associated with an increased attentional bias to emotive stimuli remains controversial. Additionally, it is unclear whether comorbid depression modulates abnormal emotional processing in OCD. This study examined attentional bias to OC-relevant scenes using a visual search task. Controls, non-depressed and depressed OCD patients searched for their personally selected positive images amongst their negative distractors, and vice versa. Whilst the OCD groups were slower than healthy individuals in rating the images, there were no group differences in the magnitude of negative bias to concern-related scenes. A second experiment employing a common set of images replicated the results on an additional sample of OCD patients. Although there was a larger bias to negative OC-related images without pre-exposure overall, no group differences in attentional bias were observed. However, OCD patients subsequently rated the images more slowly and more negatively, again suggesting post-attentional processing abnormalities. The results argue against a robust attentional bias in OCD patients, regardless of their depression status and speak to generalized difficulties disengaging from negative valence stimuli. Rather, post-attentional processing abnormalities may account for differences in emotional processing in OCD.

  14. Visual Search for Wines with a Triangle on the Label in a Virtual Store.

    Science.gov (United States)

    Zhao, Hui; Huang, Fuxing; Spence, Charles; Wan, Xiaoang

    2017-01-01

    Two experiments were conducted in a virtual reality (VR) environment in order to investigate participants' in-store visual search for bottles of wines displaying a prominent triangular shape on their label. The experimental task involved virtually moving along a wine aisle in a virtual supermarket while searching for the wine bottle on the shelf that had a different triangle on its label from the other bottles. The results of Experiment 1 revealed that the participants identified the bottle with a downward-pointing triangle on its label more rapidly than when looking for an upward-pointing triangle on the label instead. This finding replicates the downward-pointing triangle superiority (DPTS) effect, though the magnitude of this effect was more pronounced in the first as compared to the second half of the experiment, suggesting a modulating role of practice. The results of Experiment 2 revealed that the DPTS effect was also modulated by the location of the target on the shelf. Interestingly, however, the results of a follow-up survey demonstrate that the orientation of the triangle did not influence the participants' evaluation of the wine bottles. Taken together, these findings reveal how in-store the attention of consumers might be influenced by the design elements in product packaging. These results therefore suggest that shopping in a virtual supermarket might offer a practical means of assessing the shelf standout of product packaging, which has important implications for food marketing.

  15. Visual Search for Wines with a Triangle on the Label in a Virtual Store

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2017-12-01

    Full Text Available Two experiments were conducted in a virtual reality (VR environment in order to investigate participants’ in-store visual search for bottles of wines displaying a prominent triangular shape on their label. The experimental task involved virtually moving along a wine aisle in a virtual supermarket while searching for the wine bottle on the shelf that had a different triangle on its label from the other bottles. The results of Experiment 1 revealed that the participants identified the bottle with a downward-pointing triangle on its label more rapidly than when looking for an upward-pointing triangle on the label instead. This finding replicates the downward-pointing triangle superiority (DPTS effect, though the magnitude of this effect was more pronounced in the first as compared to the second half of the experiment, suggesting a modulating role of practice. The results of Experiment 2 revealed that the DPTS effect was also modulated by the location of the target on the shelf. Interestingly, however, the results of a follow-up survey demonstrate that the orientation of the triangle did not influence the participants’ evaluation of the wine bottles. Taken together, these findings reveal how in-store the attention of consumers might be influenced by the design elements in product packaging. These results therefore suggest that shopping in a virtual supermarket might offer a practical means of assessing the shelf standout of product packaging, which has important implications for food marketing.

  16. Positional priming of visual pop-out search is supported by multiple spatial reference frames

    Science.gov (United States)

    Gokce, Ahu; Müller, Hermann J.; Geyer, Thomas

    2015-01-01

    The present study investigates the representations(s) underlying positional priming of visual ‘pop-out’ search (Maljkovic and Nakayama, 1996). Three search items (one target and two distractors) were presented at different locations, in invariant (Experiment 1) or random (Experiment 2) cross-trial sequences. By these manipulations it was possible to disentangle retinotopic, spatiotopic, and object-centered priming representations. Two forms of priming were tested: target location facilitation (i.e., faster reaction times – RTs– when the trial n target is presented at a trial n-1 target relative to n-1 blank location) and distractor location inhibition (i.e., slower RTs for n targets presented at n-1 distractor compared to n-1 blank locations). It was found that target locations were coded in positional short-term memory with reference to both spatiotopic and object-centered representations (Experiment 1 vs. 2). In contrast, distractor locations were maintained in an object-centered reference frame (Experiments 1 and 2). We put forward the idea that the uncertainty induced by the experiment manipulation (predictable versus random cross-trial item displacements) modulates the transition from object- to space-based representations in cross-trial memory for target positions. PMID:26136718

  17. Positional priming of visual pop-out search is supported by multiple spatial reference frames.

    Science.gov (United States)

    Gokce, Ahu; Müller, Hermann J; Geyer, Thomas

    2015-01-01

    The present study investigates the representations(s) underlying positional priming of visual 'pop-out' search (Maljkovic and Nakayama, 1996). Three search items (one target and two distractors) were presented at different locations, in invariant (Experiment 1) or random (Experiment 2) cross-trial sequences. By these manipulations it was possible to disentangle retinotopic, spatiotopic, and object-centered priming representations. Two forms of priming were tested: target location facilitation (i.e., faster reaction times - RTs- when the trial n target is presented at a trial n-1 target relative to n-1 blank location) and distractor location inhibition (i.e., slower RTs for n targets presented at n-1 distractor compared to n-1 blank locations). It was found that target locations were coded in positional short-term memory with reference to both spatiotopic and object-centered representations (Experiment 1 vs. 2). In contrast, distractor locations were maintained in an object-centered reference frame (Experiments 1 and 2). We put forward the idea that the uncertainty induced by the experiment manipulation (predictable versus random cross-trial item displacements) modulates the transition from object- to space-based representations in cross-trial memory for target positions.

  18. Positional priming of visual pop-out search is supported by multiple spatial reference frames

    Directory of Open Access Journals (Sweden)

    Ahu eGokce

    2015-06-01

    Full Text Available The present study investigates the representations(s underlying positional priming of visual ‘pop-out’ search (Maljkovic & Nakayama, 1996. Three search items (1 target and 2 distractors were presented at different locations, in invariant (Experiment 1 or random (Experiment 2 cross-trial sequences. By these manipulations it was possible to disentangle retinotopic, spatiotopic, and object-centered priming representations. Two forms of priming were tested: target location facilitation (i.e., faster reaction times – RTs– when the trial n target is presented at a trial n-1 target relative to n-1 blank location and distractor location inhibition (i.e., slower RTs for n targets presented at n-1 distractor compared to n-1 blank locations. It was found that target locations were coded in positional short-term memory with reference to both spatiotopic and object-centered representations (Experiment 1 vs. 2. In contrast, distractor locations were maintained in an object-centered reference frame (Experiments 1 and 2. We put forward the idea that the uncertainty induced by the experiment manipulation (predictable versus random cross-trial item displacements modulates the transition from object- to space-based representations in cross-trial memory for target positions.

  19. Active training and driving-specific feedback improve older drivers' visual search prior to lane changes

    Directory of Open Access Journals (Sweden)

    Lavallière Martin

    2012-03-01

    Full Text Available Abstract Background Driving retraining classes may offer an opportunity to attenuate some effects of aging that may alter driving skills. Unfortunately, there is evidence that classroom programs (driving refresher courses do not improve the driving performance of older drivers. The aim of the current study was to evaluate if simulator training sessions with video-based feedback can modify visual search behaviors of older drivers while changing lanes in urban driving. Methods In order to evaluate the effectiveness of the video-based feedback training, 10 older drivers who received a driving refresher course and feedback about their driving performance were tested with an on-road standardized evaluation before and after participating to a simulator training program (Feedback group. Their results were compared to a Control group (12 older drivers who received the same refresher course and in-simulator active practice as the Feedback group without receiving driving-specific feedback. Results After attending the training program, the Control group showed no increase in the frequency of the visual inspection of three regions of interests (rear view and left side mirrors, and blind spot. In contrast, for the Feedback group, combining active training and driving-specific feedbacks increased the frequency of blind spot inspection by 100% (32.3 to 64.9% of verification before changing lanes. Conclusions These results suggest that simulator training combined with driving-specific feedbacks helped older drivers to improve their visual inspection strategies, and that in-simulator training transferred positively to on-road driving. In order to be effective, it is claimed that driving programs should include active practice sessions with driving-specific feedbacks. Simulators offer a unique environment for developing such programs adapted to older drivers' needs.

  20. Active training and driving-specific feedback improve older drivers' visual search prior to lane changes.

    Science.gov (United States)

    Lavallière, Martin; Simoneau, Martin; Tremblay, Mathieu; Laurendeau, Denis; Teasdale, Normand

    2012-03-02

    Driving retraining classes may offer an opportunity to attenuate some effects of aging that may alter driving skills. Unfortunately, there is evidence that classroom programs (driving refresher courses) do not improve the driving performance of older drivers. The aim of the current study was to evaluate if simulator training sessions with video-based feedback can modify visual search behaviors of older drivers while changing lanes in urban driving. In order to evaluate the effectiveness of the video-based feedback training, 10 older drivers who received a driving refresher course and feedback about their driving performance were tested with an on-road standardized evaluation before and after participating to a simulator training program (Feedback group). Their results were compared to a Control group (12 older drivers) who received the same refresher course and in-simulator active practice as the Feedback group without receiving driving-specific feedback. After attending the training program, the Control group showed no increase in the frequency of the visual inspection of three regions of interests (rear view and left side mirrors, and blind spot). In contrast, for the Feedback group, combining active training and driving-specific feedbacks increased the frequency of blind spot inspection by 100% (32.3 to 64.9% of verification before changing lanes). These results suggest that simulator training combined with driving-specific feedbacks helped older drivers to improve their visual inspection strategies, and that in-simulator training transferred positively to on-road driving. In order to be effective, it is claimed that driving programs should include active practice sessions with driving-specific feedbacks. Simulators offer a unique environment for developing such programs adapted to older drivers' needs.

  1. The effect of stimulus duration and motor response in hemispatial neglect during a visual search task.

    Directory of Open Access Journals (Sweden)

    Laura M Jelsone-Swain

    Full Text Available Patients with hemispatial neglect exhibit a myriad of profound deficits. A hallmark of this syndrome is the patients' absence of awareness of items located in their contralesional space. Many studies, however, have demonstrated that neglect patients exhibit some level of processing of these neglected items. It has been suggested that unconscious processing of neglected information may manifest as a fast denial. This theory of fast denial proposes that neglected stimuli are detected in the same way as non-neglected stimuli, but without overt awareness. We evaluated the fast denial theory by conducting two separate visual search task experiments, each differing by the duration of stimulus presentation. Specifically, in Experiment 1 each stimulus remained in the participants' visual field until a response was made. In Experiment 2 each stimulus was presented for only a brief duration. We further evaluated the fast denial theory by comparing verbal to motor task responses in each experiment. Overall, our results from both experiments and tasks showed no evidence for the presence of implicit knowledge of neglected stimuli. Instead, patients with neglect responded the same when they neglected stimuli as when they correctly reported stimulus absence. These findings thus cast doubt on the concept of the fast denial theory and its consequent implications for non-conscious processing. Importantly, our study demonstrated that the only behavior affected was during conscious detection of ipsilesional stimuli. Specifically, patients were slower to detect stimuli in Experiment 1 compared to Experiment 2, suggesting a duration effect occurred during conscious processing of information. Additionally, reaction time and accuracy were similar when reporting verbally versus motorically. These results provide new insights into the perceptual deficits associated with neglect and further support other work that falsifies the fast denial account of non

  2. Sea-ice loss boosts visual search: fish foraging and changing pelagic interactions in polar oceans.

    Science.gov (United States)

    Langbehn, Tom J; Varpe, Øystein

    2017-12-01

    Light is a central driver of biological processes and systems. Receding sea ice changes the lightscape of high-latitude oceans and more light will penetrate into the sea. This affects bottom-up control through primary productivity and top-down control through vision-based foraging. We model effects of sea-ice shading on visual search to develop a mechanistic understanding of how climate-driven sea-ice retreat affects predator-prey interactions. We adapt a prey encounter model for ice-covered waters, where prey-detection performance of planktivorous fish depends on the light cycle. We use hindcast sea-ice concentrations (past 35 years) and compare with a future no-ice scenario to project visual range along two south-north transects with different sea-ice distributions and seasonality, one through the Bering Sea and one through the Barents Sea. The transect approach captures the transition from sub-Arctic to Arctic ecosystems and allows for comparison of latitudinal differences between longitudes. We find that past sea-ice retreat has increased visual search at a rate of 2.7% to 4.2% per decade from the long-term mean; and for high latitudes, we predict a 16-fold increase in clearance rate. Top-down control is therefore predicted to intensify. Ecological and evolutionary consequences for polar marine communities and energy flows would follow, possibly also as tipping points and regime shifts. We expect species distributions to track the receding ice-edge, and in particular expect species with large migratory capacity to make foraging forays into high-latitude oceans. However, the extreme seasonality in photoperiod of high-latitude oceans may counteract such shifts and rather act as a zoogeographical filter limiting poleward range expansion. The provided mechanistic insights are relevant for pelagic ecosystems globally, including lakes where shifted distributions are seldom possible but where predator-prey consequences would be much related. As part of the discussion

  3. "Multisensory brand search: How the meaning of sounds guides consumers' visual attention": Correction to Knoeferle et al. (2016).

    Science.gov (United States)

    2017-03-01

    Reports an error in "Multisensory brand search: How the meaning of sounds guides consumers' visual attention" by Klemens M. Knoeferle, Pia Knoeferle, Carlos Velasco and Charles Spence ( Journal of Experimental Psychology: Applied , 2016[Jun], Vol 22[2], 196-210). In the article, under Experiment 2, Design and Stimuli, the set number of target products and visual distractors reported in the second paragraph should be 20 and 13, respectively: "On each trial, the 16 products shown in the display were randomly selected from a set of 20 products belonging to different categories. Out of the set of 20 products, seven were potential targets, whereas the other 13 were used as visual distractors only throughout the experiment (since they were not linked to specific usage or consumption sounds)." Consequently, Appendix A in the supplemental materials has been updated. (The following abstract of the original article appeared in record 2016-28876-002.) Building on models of crossmodal attention, the present research proposes that brand search is inherently multisensory, in that the consumers' visual search for a specific brand can be facilitated by semantically related stimuli that are presented in another sensory modality. A series of 5 experiments demonstrates that the presentation of spatially nonpredictive auditory stimuli associated with products (e.g., usage sounds or product-related jingles) can crossmodally facilitate consumers' visual search for, and selection of, products. Eye-tracking data (Experiment 2) revealed that the crossmodal effect of auditory cues on visual search manifested itself not only in RTs, but also in the earliest stages of visual attentional processing, thus suggesting that the semantic information embedded within sounds can modulate the perceptual saliency of the target products' visual representations. Crossmodal facilitation was even observed for newly learnt associations between unfamiliar brands and sonic logos, implicating multisensory short

  4. The Effects of Dynamic Assessment Procedures on Raven Matrices Performance, Visual Search Behavior, Test Anxiety and Test Orientation.

    Science.gov (United States)

    Bethge, Hans-Jorg; And Others

    1982-01-01

    Dynamic assessment procedures involving either verbalization or elaborated feedback lead to higher levels of Ravens Matrices performance, modified visual search behaviors, reduced test anxiety, and reduced negative orientations to the testing situation in third graders. Results are interpreted on offering construct validation to the assessment…

  5. How Prior Knowledge and Colour Contrast Interfere Visual Search Processes in Novice Learners: An Eye Tracking Study

    Science.gov (United States)

    Sonmez, Duygu; Altun, Arif; Mazman, Sacide Guzin

    2012-01-01

    This study investigates how prior content knowledge and prior exposure to microscope slides on the phases of mitosis effect students' visual search strategies and their ability to differentiate cells that are going through any phases of mitosis. Two different sets of microscope slide views were used for this purpose; with high and low colour…

  6. Target-distractor similarity has a larger impact on visual search in school-age children than spacing

    NARCIS (Netherlands)

    Huurneman, B.; Boonstra, F.N.

    2015-01-01

    In typically developing children, crowding decreases with increasing age. The influence of target-distractor similarity with respect to orientation and element spacing on visual search performance was investigated in 29 school-age children with normal vision (4- to 6-year-olds [N = 16], 7- to

  7. EEG and Eye Tracking Signatures of Target Encoding during Structured Visual Search

    Directory of Open Access Journals (Sweden)

    Anne-Marie Brouwer

    2017-05-01

    Full Text Available EEG and eye tracking variables are potential sources of information about the underlying processes of target detection and storage during visual search. Fixation duration, pupil size and event related potentials (ERPs locked to the onset of fixation or saccade (saccade-related potentials, SRPs have been reported to differ dependent on whether a target or a non-target is currently fixated. Here we focus on the question of whether these variables also differ between targets that are subsequently reported (hits and targets that are not (misses. Observers were asked to scan 15 locations that were consecutively highlighted for 1 s in pseudo-random order. Highlighted locations displayed either a target or a non-target stimulus with two, three or four targets per trial. After scanning, participants indicated which locations had displayed a target. To induce memory encoding failures, participants concurrently performed an aurally presented math task (high load condition. In a low load condition, participants ignored the math task. As expected, more targets were missed in the high compared with the low load condition. For both conditions, eye tracking features distinguished better between hits and misses than between targets and non-targets (with larger pupil size and shorter fixations for missed compared with correctly encoded targets. In contrast, SRP features distinguished better between targets and non-targets than between hits and misses (with average SRPs showing larger P300 waveforms for targets than for non-targets. Single trial classification results were consistent with these averages. This work suggests complementary contributions of eye and EEG measures in potential applications to support search and detect tasks. SRPs may be useful to monitor what objects are relevant to an observer, and eye variables may indicate whether the observer should be reminded of them later.

  8. Reading wiring diagrams made easier for maintenance operators: contribution from research in visual attention and visual search

    International Nuclear Information System (INIS)

    Ponthieu, L.; Wolfe, J.M.

    1994-07-01

    This work has been carried out while the author was visiting the Visual Psychophysics lab at the Center for Ophthalmic Research, Harvard Medical School. The general framework is the design of a wiring diagrams visualization system for maintenance operators in electric plants. This study concentrates on how knowledge and experimental techniques from visual attention can help this goal. From this standpoint, the visualization system must best exploit the human visual system abilities. As electronic databases containing all the diagrams will soon be available, it is important to think in advance the display techniques. Presently, maintenance operators favor working with paper printouts even where such databases are already available. The study shows why such an approach is valuable for the design of a display that fits the operator's tasks. Beyond that, this work has been a mean to learn the experimental techniques of cognitive sciences in an applied frame. (authors). 9 figs., 5 annexes

  9. The effects of action video game experience on the time course of inhibition of return and the efficiency of visual search.

    Science.gov (United States)

    Castel, Alan D; Pratt, Jay; Drummond, Emily

    2005-06-01

    The ability to efficiently search the visual environment is a critical function of the visual system, and recent research has shown that experience playing action video games can influence visual selective attention. The present research examined the similarities and differences between video game players (VGPs) and non-video game players (NVGPs) in terms of the ability to inhibit attention from returning to previously attended locations, and the efficiency of visual search in easy and more demanding search environments. Both groups were equally good at inhibiting the return of attention to previously cued locations, although VGPs displayed overall faster reaction times to detect targets. VGPs also showed overall faster response time for easy and difficult visual search tasks compared to NVGPs, largely attributed to faster stimulus-response mapping. The findings suggest that relative to NVGPs, VGPs rely on similar types of visual processing strategies but possess faster stimulus-response mappings in visual attention tasks.

  10. Group Augmentation in Realistic Visual-Search Decisions via a Hybrid Brain-Computer Interface.

    Science.gov (United States)

    Valeriani, Davide; Cinel, Caterina; Poli, Riccardo

    2017-08-10

    Groups have increased sensing and cognition capabilities that typically allow them to make better decisions. However, factors such as communication biases and time constraints can lead to less-than-optimal group decisions. In this study, we use a hybrid Brain-Computer Interface (hBCI) to improve the performance of groups undertaking a realistic visual-search task. Our hBCI extracts neural information from EEG signals and combines it with response times to build an estimate of the decision confidence. This is used to weigh individual responses, resulting in improved group decisions. We compare the performance of hBCI-assisted groups with the performance of non-BCI groups using standard majority voting, and non-BCI groups using weighted voting based on reported decision confidence. We also investigate the impact on group performance of a computer-mediated form of communication between members. Results across three experiments suggest that the hBCI provides significant advantages over non-BCI decision methods in all cases. We also found that our form of communication increases individual error rates by almost 50% compared to non-communicating observers, which also results in worse group performance. Communication also makes reported confidence uncorrelated with the decision correctness, thereby nullifying its value in weighing votes. In summary, best decisions are achieved by hBCI-assisted, non-communicating groups.

  11. Exploratory search in an audio-visual archive: evaluating a professional search tool for non-professional users

    NARCIS (Netherlands)

    Bron, M.; van Gorp, J.; Nack, F.; de Rijke, M.

    2011-01-01

    As archives are opening up and publishing their content online, the general public can now directly access archive collections. To support access, archives typically provide the public with their internal search tools that were originally intended for professional archivists. We conduct a

  12. SEARCH

    International Development Research Centre (IDRC) Digital Library (Canada)

    Chaitali Sinha

    Anexo B: Lista de verificación para presentar una nota conceptual en el marco de IDRC-SEARCH ....... 17 .... incluir investigación primaria y/o síntesis de estudios existentes, para generar nuevo conocimiento. Los .... de datos entre grupos diferentes de usuarios (trabajadores de la salud comunitaria, funcionarios de salud.

  13. Intrinsic motivation and attentional capture from gamelike features in a visual search task.

    Science.gov (United States)

    Miranda, Andrew T; Palmer, Evan M

    2014-03-01

    In psychology research studies, the goals of the experimenter and the goals of the participants often do not align. Researchers are interested in having participants who take the experimental task seriously, whereas participants are interested in earning their incentive (e.g., money or course credit) as quickly as possible. Creating experimental methods that are pleasant for participants and that reward them for effortful and accurate data generation, while not compromising the scientific integrity of the experiment, would benefit both experimenters and participants alike. Here, we explored a gamelike system of points and sound effects that rewarded participants for fast and accurate responses. We measured participant engagement at both cognitive and perceptual levels and found that the point system (which invoked subtle, anonymous social competition between participants) led to positive intrinsic motivation, while the sound effects (which were pleasant and arousing) led to attentional capture for rewarded colors. In a visual search task, points were awarded after each trial for fast and accurate responses, accompanied by short, pleasant sound effects. We adapted a paradigm from Anderson, Laurent, and Yantis (Proceedings of the National Academy of Sciences 108(25):10367-10371, 2011b), in which participants completed a training phase during which red and green targets were probabilistically associated with reward (a point bonus multiplier). During a test phase, no points or sounds were delivered, color was irrelevant to the task, and previously rewarded targets were sometimes presented as distractors. Significantly longer response times on trials in which previously rewarded colors were present demonstrated attentional capture, and positive responses to a five-question intrinsic-motivation scale demonstrated participant engagement.

  14. Do synesthetes have a general advantage in visual search and episodic memory? A case for group studies.

    Directory of Open Access Journals (Sweden)

    Nicolas Rothen

    Full Text Available BACKGROUND: Some studies, most of them case-reports, suggest that synesthetes have an advantage in visual search and episodic memory tasks. The goal of this study was to examine this hypothesis in a group study. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we tested thirteen grapheme-color synesthetes and we compared their performance on a visual search task and a memory test to an age-, handedness-, education-, and gender-matched control group. The results showed no significant group differences (all relevant ps>.50. For the visual search task effect sizes indicated a small advantage for synesthetes (Cohen's d between .19 and .32. No such advantage was found for episodic memory (Cohen's d<.05. CONCLUSIONS/SIGNIFICANCE: The results indicate that synesthesia per se does not seem to lead to a strong performance advantage. Rather, the superior performance of synesthetes observed in some case-report studies may be due to individual differences, to a selection bias or to a strategic use of synesthesia as a mnemonic. In order to establish universal effects of synesthesia on cognition single-case studies must be complemented by group studies.

  15. Awareness in contextual cueing of visual search as measured with concurrent access- and phenomenal-consciousness tasks.

    Science.gov (United States)

    Schlagbauer, Bernhard; Müller, Hermann J; Zehetleitner, Michael; Geyer, Thomas

    2012-10-25

    In visual search, context information can serve as a cue to guide attention to the target location. When observers repeatedly encounter displays with identical target-distractor arrangements, reaction times (RTs) are faster for repeated relative to nonrepeated displays, the latter containing novel configurations. This effect has been termed "contextual cueing." The present study asked whether information about the target location in repeated displays is "explicit" (or "conscious") in nature. To examine this issue, observers performed a test session (after an initial training phase in which RTs to repeated and nonrepeated displays were measured) in which the search stimuli were presented briefly and terminated by visual masks; following this, observers had to make a target localization response (with accuracy as the dependent measure) and indicate their visual experience and confidence associated with the localization response. The data were examined at the level of individual displays, i.e., in terms of whether or not a repeated display actually produced contextual cueing. The results were that (a) contextual cueing was driven by only a very small number of about four actually learned configurations; (b) localization accuracy was increased for learned relative to nonrepeated displays; and (c) both consciousness measures were enhanced for learned compared to nonrepeated displays. It is concluded that contextual cueing is driven by only a few repeated displays and the ability to locate the target in these displays is associated with increased visual experience.

  16. Right away: A late, right-lateralized category effect complements an early, left-lateralized category effect in visual search.

    Science.gov (United States)

    Constable, Merryn D; Becker, Stefanie I

    2017-10-01

    According to the Sapir-Whorf hypothesis, learned semantic categories can influence early perceptual processes. A central finding in support of this view is the lateralized category effect-namely, the finding that categorically different colors (e.g., blue and green hues) can be discriminated faster than colors within the same color category (e.g., different hues of green), especially when they are presented in the right visual field. Because the right visual field projects to the left hemisphere, this finding has been popularly couched in terms of the left-lateralization of language. However, other studies have reported bilateral category effects, which has led some researchers to question the linguistic origins of the effect. Here we examined the time course of lateralized and bilateral category effects in the classical visual search paradigm by means of eyetracking and RT distribution analyses. Our results show a bilateral category effect in the manual responses, which is combined of an early, left-lateralized category effect and a later, right-lateralized category effect. The newly discovered late, right-lateralized category effect occurred only when observers had difficulty locating the target, indicating a specialization of the right hemisphere to find categorically different targets after an initial error. The finding that early and late stages of visual search show different lateralized category effects can explain a wide range of previously discrepant findings.

  17. More than Just Finding Color: Strategy in Global Visual Search Is Shaped by Learned Target Probabilities

    Science.gov (United States)

    Williams, Carrick C.; Pollatsek, Alexander; Cave, Kyle R.; Stroud, Michael J.

    2009-01-01

    In 2 experiments, eye movements were examined during searches in which elements were grouped into four 9-item clusters. The target (a red or blue "T") was known in advance, and each cluster contained different numbers of target-color elements. Rather than color composition of a cluster invariantly guiding the order of search though…

  18. Visual Impairment

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Visual Impairment KidsHealth / For Teens / Visual Impairment What's in ... with the brain, making vision impossible. What Is Visual Impairment? Many people have some type of visual ...

  19. Visual search and line bisection in hemianopia: computational modelling of cortical compensatory mechanisms and comparison with hemineglect.

    Science.gov (United States)

    Lanyon, Linda J; Barton, Jason J S

    2013-01-01

    Hemianopia patients have lost vision from the contralateral hemifield, but make behavioural adjustments to compensate for this field loss. As a result, their visual performance and behaviour contrast with those of hemineglect patients who fail to attend to objects contralateral to their lesion. These conditions differ in their ocular fixations and perceptual judgments. During visual search, hemianopic patients make more fixations in contralesional space while hemineglect patients make fewer. During line bisection, hemianopic patients fixate the contralesional line segment more and make a small contralesional bisection error, while hemineglect patients make few contralesional fixations and a larger ipsilesional bisection error. Hence, there is an attentional failure for contralesional space in hemineglect but a compensatory adaptation to attend more to the blind side in hemianopia. A challenge for models of visual attentional processes is to show how compensation is achieved in hemianopia, and why such processes are hindered or inaccessible in hemineglect. We used a neurophysiology-derived computational model to examine possible cortical compensatory processes in simulated hemianopia from a V1 lesion and compared results with those obtained with the same processes under conditions of simulated hemineglect from a parietal lesion. A spatial compensatory bias to increase attention contralesionally replicated hemianopic scanning patterns during visual search but not during line bisection. To reproduce the latter required a second process, an extrastriate lateral connectivity facilitating form completion into the blind field: this allowed accurate placement of fixations on contralesional stimuli and reproduced fixation patterns and the contralesional bisection error of hemianopia. Neither of these two cortical compensatory processes was effective in ameliorating the ipsilesional bias in the hemineglect model. Our results replicate normal and pathological patterns of

  20. Comparing the effect of temporal delay on the availability of egocentric and allocentric information in visual search.

    Science.gov (United States)

    Ball, Keira; Birch, Yan; Lane, Alison; Ellison, Amanda; Schenk, Thomas

    2017-07-28

    Frames of reference play a central role in perceiving an object's location and reaching to pick that object up. It is thought that the ventral stream, believed to subserve vision for perception, utilises allocentric coding, while the dorsal stream, argued to be responsible for vision for action, primarily uses an egocentric reference frame. We have previously shown that egocentric representations can survive a delay; however, it is possible that in comparison to allocentric information, egocentric information decays more rapidly. Here we directly compare the effect of delay on the availability of egocentric and allocentric representations. We used spatial priming in visual search and repeated the location of the target relative to either a landmark in the search array (allocentric condition) or the observer's body (egocentric condition). Three inter-trial intervals created minimum delays between two consecutive trials of 2, 4, or 8seconds. In both conditions, search times to primed locations were faster than search times to un-primed locations. In the egocentric condition the effects were driven by a reduction in search times when egocentric information was repeated, an effect that was observed at all three delays. In the allocentric condition while search times did not change when the allocentric information was repeated, search times to un-primed target locations became slower. We conclude that egocentric representations are not as transient as previously thought but instead this information is still available, and can influence behaviour, after lengthy periods of delay. We also discuss the possible origins of the differences between allocentric and egocentric priming effects. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Fat Content Modulates Rapid Detection of Food: A Visual Search Study Using Fast Food and Japanese Diet

    Directory of Open Access Journals (Sweden)

    Reiko Sawada

    2017-06-01

    Full Text Available Rapid detection of food is crucial for the survival of organisms. However, previous visual search studies have reported discrepant results regarding the detection speeds for food vs. non-food items; some experiments showed faster detection of food than non-food, whereas others reported null findings concerning any speed advantage for the detection of food vs. non-food. Moreover, although some previous studies showed that fat content can affect visual attention for food, the effect of fat content on the detection of food remains unclear. To investigate these issues, we measured reaction times (RTs during a visual search task in which participants with normal weight detected high-fat food (i.e., fast food, low-fat food (i.e., Japanese diet, and non-food (i.e., kitchen utensils targets within crowds of non-food distractors (i.e., cars. Results showed that RTs for food targets were shorter than those for non-food targets. Moreover, the RTs for high-fat food were shorter than those for low-fat food. These results suggest that food is more rapidly detected than non-food within the environment and that a higher fat content in food facilitates rapid detection.

  2. Computer-Assisted Visual Search/Decision Aids as a Training Tool for Mammography

    National Research Council Canada - National Science Library

    Nodine, Calvin

    2000-01-01

    .... In the first two years we carried out two experiments. The first equated experience by comparing perceptual skills of expert radiologists with lay people searching non-medical pictorial scenes for hidden targets...

  3. Training and transfer of training in rapid visual search for camouflaged targets.

    Science.gov (United States)

    Neider, Mark B; Ang, Cher Wee; Voss, Michelle W; Carbonari, Ronald; Kramer, Arthur F

    2013-01-01

    Previous examinations of search under camouflage conditions have reported that performance improves with training and that training can engender near perfect transfer to similar, but novel camouflage-type displays [1]. What remains unclear, however, are the cognitive mechanisms underlying these training improvements and transfer benefits. On the one hand, improvements and transfer benefits might be associated with higher-level overt strategy shifts, such as through the restriction of eye movements to target-likely (background) display regions. On the other hand, improvements and benefits might be related to the tuning of lower-level perceptual processes, such as figure-ground segregation. To decouple these competing possibilities we had one group of participants train on camouflage search displays and a control group train on non-camouflage displays. Critically, search displays were rapidly presented, precluding eye movements. Before and following training, all participants completed transfer sessions in which they searched novel displays. We found that search performance on camouflage displays improved with training. Furthermore, participants who trained on camouflage displays suffered no performance costs when searching novel displays following training. Our findings suggest that training to break camouflage is related to the tuning of perceptual mechanisms and not strategic shifts in overt attention.

  4. In (visual) search for a new distraction: the efficiency of a novel attentional deployment versus semantic meaning regulation strategies.

    Science.gov (United States)

    Sheppes, Gal; Brady, William J; Samson, Andrea C

    2014-01-01

    Cognitive emotion regulation strategies are considered the king's highway to control affective reactions. Two broad categories of cognitive regulation are attentional deployment and semantic meaning. The basic distinctive feature between these categories is the type of conflict between regulatory and emotional processes for dominance, with an early attentional selection conflict in attentional deployment and a late appraisal selection conflict in semantic meaning. However, prior studies that tested the relative efficacy of these two regulatory categories varied the type and the degree of conflict. Our major goal was to test the relative efficacy of a novel attentional deployment strategy (visual search distraction) and a classic semantic meaning strategy (reappraisal) that have a different type of conflict but a matched degree of conflict. Specifically, visual search distraction involves a strong degree of attentional selection conflict manifested in attending subtle non-emotional features that are camouflaged within potent negative emotional stimuli. Reappraisal involves a strong degree of appraisal selection conflict manifested in construing neutral reappraisals that rely on potent negative emotional appraisals. Based on our theoretical model we hypothesized and found that visual search distraction was as effective as cognitive reappraisal in down-regulating the experience of low intensity of negative emotion (Study 1), but more effective, less effortful, and more strongly blocking emotional information processing than cognitive reappraisal when regulating high intensity (Study 2). A final study ruled out a demand characteristics explanation by showing that participants' expectations about how they should feel diverged from how they actually reported feeling following regulation (Study 3). Our findings suggest that the basic difference in the type rather than degree of conflict between attentional deployment and semantic meaning determines strategies' outcome.

  5. In (visual Search for a New Distraction: The Efficiency of a Novel Attentional Deployment Versus Semantic Meaning Regulation Strategies

    Directory of Open Access Journals (Sweden)

    Gal eSheppes

    2014-04-01

    Full Text Available Cognitive emotion regulation strategies are considered the king’s highway to control affective reactions. Two broad categories of cognitive regulation are attentional deployment and semantic meaning. The basic distinctive feature between these categories is the type of conflict between regulatory and emotional processes for dominance, with an early attentional selection conflict in attentional deployment and a late appraisal selection conflict in semantic meaning. However, prior studies that tested the relative efficacy of these two regulatory categories varied the type and the degree of conflict. Our major goal was to test the relative efficacy of a novel attentional deployment strategy (visual search distraction and a classic semantic meaning strategy (reappraisal that have a different type of conflict but a matched degree of conflict. Specifically, visual search distraction involves a strong degree of attentional selection conflict manifested in attending subtle non-emotional features that are camouflaged within potent negative emotional stimuli. Reappraisal involves a strong degree of appraisal selection conflict manifested in construing neutral reappraisals that rely on potent negative emotional appraisals. Based on our theoretical model we hypothesized and found that visual search distraction was as effective as cognitive reappraisal in down-regulating the experience of low intensity of negative emotion (Study 1, but more effective, less effortful, and more strongly blocking emotional information processing than cognitive reappraisal when regulating high intensity (Study 2. A final study ruled out a demand characteristics explanation by showing that participants’ expectations about how they should feel diverged from how they actually reported feeling following regulation (Study 3. Our findings suggest that the basic difference in the type rather than degree of conflict between attentional deployment and semantic meaning determines

  6. C-State: an interactive web app for simultaneous multi-gene visualization and comparative epigenetic pattern search.

    Science.gov (United States)

    Sowpati, Divya Tej; Srivastava, Surabhi; Dhawan, Jyotsna; Mishra, Rakesh K

    2017-09-13

    Comparative epigenomic analysis across multiple genes presents a bottleneck for bench biologists working with NGS data. Despite the development of standardized peak analysis algorithms, the identification of novel epigenetic patterns and their visualization across gene subsets remains a challenge. We developed a fast and interactive web app, C-State (Chromatin-State), to query and plot chromatin landscapes across multiple loci and cell types. C-State has an interactive, JavaScript-based graphical user interface and runs locally in modern web browsers that are pre-installed on all computers, thus eliminating the need for cumbersome data transfer, pre-processing and prior programming knowledge. C-State is unique in its ability to extract and analyze multi-gene epigenetic information. It allows for powerful GUI-based pattern searching and visualization. We include a case study to demonstrate its potential for identifying user-defined epigenetic trends in context of gene expression profiles.

  7. Textual and Visual Information in eWOM: A Gap Between Preferences in Information Search and Diffusion

    DEFF Research Database (Denmark)

    Lee, Geunhee; Tussyadiah, Iis

    2010-01-01

    This article examines the gap between travel-related information search and diffusion by online users in order to better understand the important role of visual information in electronic word of mouth (eWOM). Several analyses were conducted to investigate differences in travelers' preferences...... spreading eWOM. This study discusses the reasons for this gap and the individual differences in travelers' information format preferences when retrieving and diffusing travel-related information online. Managerial implications for destination marketers and user-generated content platform managers...... for particular forms of information. The results suggest that textual-visual information formats (i.e., photos and/or videos combined with text) have a greater influence on motivation to travel than text-only information. On the other hand, experienced travelers tend to contribute text-only information when...

  8. Seek and you shall remember: Scene semantics interact with visual search to build better memories

    Science.gov (United States)

    Draschkow, Dejan; Wolfe, Jeremy M.; Võ, Melissa L.-H.

    2014-01-01

    Memorizing critical objects and their locations is an essential part of everyday life. In the present study, incidental encoding of objects in naturalistic scenes during search was compared to explicit memorization of those scenes. To investigate if prior knowledge of scene structure influences these two types of encoding differently, we used meaningless arrays of objects as well as objects in real-world, semantically meaningful images. Surprisingly, when participants were asked to recall scenes, their memory performance was markedly better for searched objects than for objects they had explicitly tried to memorize, even though participants in the search condition were not explicitly asked to memorize objects. This finding held true even when objects were observed for an equal amount of time in both conditions. Critically, the recall benefit for searched over memorized objects in scenes was eliminated when objects were presented on uniform, non-scene backgrounds rather than in a full scene context. Thus, scene semantics not only help us search for objects in naturalistic scenes, but appear to produce a representation that supports our memory for those objects beyond intentional memorization. PMID:25015385

  9. The effects of memory load and stimulus relevance on the EEG during a visual selective memory search task : An ERP and ERD/ERS study

    NARCIS (Netherlands)

    Gomarus, HK; Althaus, M; Wijers, AA; Minderaa, RB

    Objective: Psychophysiological correlates of selective attention and working memory were investigated in a group of 18 healthy children using a visually presented selective mernory search task. Methods: Subjects had to memorize one (load 1) or 3 (load3) letters (memory set) and search for these

  10. Comparing the Precision of Information Retrieval of MeSH-Controlled Vocabulary Search Method and a Visual Method in the Medline Medical Database.

    Science.gov (United States)

    Hariri, Nadjla; Ravandi, Somayyeh Nadi

    2014-01-01

    Medline is one of the most important databases in the biomedical field. One of the most important hosts for Medline is Elton B. Stephens CO. (EBSCO), which has presented different search methods that can be used based on the needs of the users. Visual search and MeSH-controlled search methods are among the most common methods. The goal of this research was to compare the precision of the retrieved sources in the EBSCO Medline base using MeSH-controlled and visual search methods. This research was a semi-empirical study. By holding training workshops, 70 students of higher education in different educational departments of Kashan University of Medical Sciences were taught MeSH-Controlled and visual search methods in 2012. Then, the precision of 300 searches made by these students was calculated based on Best Precision, Useful Precision, and Objective Precision formulas and analyzed in SPSS software using the independent sample T Test, and three precisions obtained with the three precision formulas were studied for the two search methods. The mean precision of the visual method was greater than that of the MeSH-Controlled search for all three types of precision, i.e. Best Precision, Useful Precision, and Objective Precision, and their mean precisions were significantly different (P searches. Fifty-three percent of the participants in the research also mentioned that the use of the combination of the two methods produced better results. For users, it is more appropriate to use a natural, language-based method, such as the visual method, in the EBSCO Medline host than to use the controlled method, which requires users to use special keywords. The potential reason for their preference was that the visual method allowed them more freedom of action.

  11. Sonification and Visualization of Predecisional Information Search: Identifying Toolboxes in Children

    Science.gov (United States)

    Betsch, Tilmann; Wünsche, Kirsten; Großkopf, Armin; Schröder, Klara; Stenmans, Rachel

    2018-01-01

    Prior evidence has suggested that preschoolers and elementary schoolers search information largely with no systematic plan when making decisions in probabilistic environments. However, this finding might be due to the insensitivity of standard classification methods that assume a lack of variance in decision strategies for tasks of the same kind.…

  12. Influence of music and distraction on visual search performance of participants with high and low affect intensity.

    Science.gov (United States)

    Crust, Lee; Clough, Peter J; Robertson, Colin

    2004-06-01

    This study examined the role of music and distraction on the performance of a visual search task (grid test) for 57 volunteer sports science undergraduates (M = 21.6 yr., SD = 3.0), comprising 39 men and 18 women who were subsequently classified as either high or low in Affect Intensity (responsiveness to emotional stimuli). Participants were instructed to identify as many numbers in sequence from an 8 x 8 concentration grid while being randomly exposed to four conditions: silence (Control), distraction (Talking), Instrumental Music, and Lyrical Music. Each trial lasted 120 sec., with 180-sec. rest periods between trials. A one-way repeated-measures analysis of variance and Newman-Keuls post hoc analysis for the entire sample (N = 57) indicated that significantly higher scores on the grid test were attained with Lyrical Music than with Instrumental Music (p Music condition had significantly better performance than either the Talking or Control condition (p music may facilitate a simple visual search task.

  13. Introducing a New Interface for the Online MagIC Database by Integrating Data Uploading, Searching, and Visualization

    Science.gov (United States)

    Jarboe, N.; Minnett, R.; Constable, C.; Koppers, A. A.; Tauxe, L.

    2013-12-01

    The Magnetics Information Consortium (MagIC) is dedicated to supporting the paleomagnetic, geomagnetic, and rock magnetic communities through the development and maintenance of an online database (http://earthref.org/MAGIC/), data upload and quality control, searches, data downloads, and visualization tools. While MagIC has completed importing some of the IAGA paleomagnetic databases (TRANS, PINT, PSVRL, GPMDB) and continues to import others (ARCHEO, MAGST and SECVR), further individual data uploading from the community contributes a wealth of easily-accessible rich datasets. Previously uploading of data to the MagIC database required the use of an Excel spreadsheet using either a Mac or PC. The new method of uploading data utilizes an HTML 5 web interface where the only computer requirement is a modern browser. This web interface will highlight all errors discovered in the dataset at once instead of the iterative error checking process found in the previous Excel spreadsheet data checker. As a web service, the community will always have easy access to the most up-to-date and bug free version of the data upload software. The filtering search mechanism of the MagIC database has been changed to a more intuitive system where the data from each contribution is displayed in tables similar to how the data is uploaded (http://earthref.org/MAGIC/search/). Searches themselves can be saved as a permanent URL, if desired. The saved search URL could then be used as a citation in a publication. When appropriate, plots (equal area, Zijderveld, ARAI, demagnetization, etc.) are associated with the data to give the user a quicker understanding of the underlying dataset. The MagIC database will continue to evolve to meet the needs of the paleomagnetic, geomagnetic, and rock magnetic communities.

  14. Convolutional Neural Networks as Feature Extractors for Data Scarce Visual Searches

    Science.gov (United States)

    2016-09-01

    Nearest Neighbors, image classification, data scarcity, transfer learning , activation codes, high-dimensional space, cosine similarity, Euclidean distance...single image . In machine learning , to classify images into different categories, a data-driven approach is used. Instead of developing an algorithm that...class from the visual appearance. Data driven learning can be supervised or unsupervised . In the case of supervised learning all the samples must be

  15. Ungulates rely less on visual cues, but more on adapting movement behaviour, when searching for forage.

    Science.gov (United States)

    Venter, Jan A; Prins, Herbert H T; Mashanova, Alla; Slotow, Rob

    2017-01-01

    Finding suitable forage patches in a heterogeneous landscape, where patches change dynamically both spatially and temporally could be challenging to large herbivores, especially if they have no a priori knowledge of the location of the patches. We tested whether three large grazing herbivores with a variety of different traits improve their efficiency when foraging at a heterogeneous habitat patch scale by using visual cues to gain a priori knowledge about potential higher value foraging patches. For each species (zebra ( Equus burchelli ), red hartebeest ( Alcelaphus buselaphus subspecies camaa ) and eland ( Tragelaphus oryx )), we used step lengths and directionality of movement to infer whether they were using visual cues to find suitable forage patches at a habitat patch scale. Step lengths were significantly longer for all species when moving to non-visible patches than to visible patches, but all movements showed little directionality. Of the three species, zebra movements were the most directional. Red hartebeest had the shortest step lengths and zebra the longest. We conclude that these large grazing herbivores may not exclusively use visual cues when foraging at a habitat patch scale, but would rather adapt their movement behaviour, mainly step length, to the heterogeneity of the specific landscape.

  16. Micro and regular saccades across the lifespan during a visual search of “Where’s Waldo” puzzles☆

    Science.gov (United States)

    Port, Nicholas L.; Trimberger, Jane; Hitzeman, Steve; Redick, Bryan; Beckerman, Stephen

    2015-01-01

    Despite the fact that different aspects of visual-motor control mature at different rates and aging is associated with declines in both sensory and motor function, little is known about the relationship between microsaccades and either development or aging. Using a sample of 343 individuals ranging in age from 4 to 66 and a task that has been shown to elicit a high frequency of microsaccades (solving Where’s Waldo puzzles), we explored microsaccade frequency and kinematics (main sequence curves) as a function of age. Taking advantage of the large size of our dataset (1,83,893 saccades), we also address (a) the saccade amplitude limit at which video eye trackers are able to accurately measure microsaccades and (b) the degree and consistency of saccade kinematics at varying amplitudes and directions. Using a modification of the Engbert–Mergenthaler saccade detector, we found that even the smallest amplitude movements (0.25–0.5°) demonstrate basic saccade kinematics. With regard to development and aging, both microsaccade and regular saccade frequency exhibited a very small increase across the life span. Visual search ability, as per many other aspects of visual performance, exhibited a U-shaped function over the lifespan. Finally, both large horizontal and moderate vertical directional biases were detected for all saccade sizes. PMID:26049037

  17. When and why might a Computer Aided Detection (CAD) system interfere with visual search? An eye-tracking study

    Science.gov (United States)

    Drew, Trafton; Cunningham, Corbin; Wolfe, Jeremy

    2012-01-01

    Rational and Objectives Computer Aided Detection (CAD) systems are intended to improve performance. This study investigates how CAD might actually interfere with a visual search task. This is a laboratory study with implications for clinical use of CAD. Methods 47 naïve observers in two studies were asked to search for a target, embedded in 1/f2.4 noise while we monitored their eye-movements. For some observers, a CAD system marked 75% of targets and 10% of distractors while other observers completed the study without CAD. In Experiment 1, the CAD system’s primary function was to tell observers where the target might be. In Experiment 2, CAD provided information about target identity. Results In Experiment 1, there was a significant enhancement of observer sensitivity in the presence of CAD (t(22)=4.74, pCAD system were missed more frequently than equivalent targets in No CAD blocks of the experiment (t(22)=7.02, pCAD, but also no significant cost on sensitivity to unmarked targets (t(22)=0.6, p=n.s.). Finally, in both experiments, CAD produced reliable changes in eye-movements: CAD observers examined a lower total percentage of the search area than the No CAD observers (Ex 1: t(48)=3.05, pCAD signals do not combine with observers’ unaided performance in a straight-forward manner. CAD can engender a sense of certainty that can lead to incomplete search and elevated chances of missing unmarked stimuli. PMID:22958720

  18. Neural Activity Associated with Visual Search for Line Drawings on AAC Displays: An Exploration of the Use of fMRI.

    Science.gov (United States)

    Wilkinson, Krista M; Dennis, Nancy A; Webb, Christina E; Therrien, Mari; Stradtman, Megan; Farmer, Jacquelyn; Leach, Raevynn; Warrenfeltz, Megan; Zeuner, Courtney

    2015-01-01

    Visual aided augmentative and alternative communication (AAC) consists of books or technologies that contain visual symbols to supplement spoken language. A common observation concerning some forms of aided AAC is that message preparation can be frustratingly slow. We explored the uses of fMRI to examine the neural correlates of visual search for line drawings on AAC displays in 18 college students under two experimental conditions. Under one condition, the location of the icons remained stable and participants were able to learn the spatial layout of the display. Under the other condition, constant shuffling of the locations of the icons prevented participants from learning the layout, impeding rapid search. Brain activation was contrasted under these conditions. Rapid search in the stable display was associated with greater activation of cortical and subcortical regions associated with memory, motor learning, and dorsal visual pathways compared to the search in the unpredictable display. Rapid search for line drawings on stable AAC displays involves not just the conceptual knowledge of the symbol meaning but also the integration of motor, memory, and visual-spatial knowledge about the display layout. Further research must study individuals who use AAC, as well as the functional effect of interventions that promote knowledge about array layout.

  19. BUILDING A BILLION SPATIO-TEMPORAL OBJECT SEARCH AND VISUALIZATION PLATFORM

    Directory of Open Access Journals (Sweden)

    D. Kakkar

    2017-10-01

    Full Text Available With funding from the Sloan Foundation and Harvard Dataverse, the Harvard Center for Geographic Analysis (CGA has developed a prototype spatio-temporal visualization platform called the Billion Object Platform or BOP. The goal of the project is to lower barriers for scholars who wish to access large, streaming, spatio-temporal datasets. The BOP is now loaded with the latest billion geo-tweets, and is fed a real-time stream of about 1 million tweets per day. The geo-tweets are enriched with sentiment and census/admin boundary codes when they enter the system. The system is open source and is currently hosted on Massachusetts Open Cloud (MOC, an OpenStack environment with all components deployed in Docker orchestrated by Kontena. This paper will provide an overview of the BOP architecture, which is built on an open source stack consisting of Apache Lucene, Solr, Kafka, Zookeeper, Swagger, scikit-learn, OpenLayers, and AngularJS. The paper will further discuss the approach used for harvesting, enriching, streaming, storing, indexing, visualizing and querying a billion streaming geo-tweets.

  20. Building a Billion Spatio-Temporal Object Search and Visualization Platform

    Science.gov (United States)

    Kakkar, D.; Lewis, B.

    2017-10-01

    With funding from the Sloan Foundation and Harvard Dataverse, the Harvard Center for Geographic Analysis (CGA) has developed a prototype spatio-temporal visualization platform called the Billion Object Platform or BOP. The goal of the project is to lower barriers for scholars who wish to access large, streaming, spatio-temporal datasets. The BOP is now loaded with the latest billion geo-tweets, and is fed a real-time stream of about 1 million tweets per day. The geo-tweets are enriched with sentiment and census/admin boundary codes when they enter the system. The system is open source and is currently hosted on Massachusetts Open Cloud (MOC), an OpenStack environment with all components deployed in Docker orchestrated by Kontena. This paper will provide an overview of the BOP architecture, which is built on an open source stack consisting of Apache Lucene, Solr, Kafka, Zookeeper, Swagger, scikit-learn, OpenLayers, and AngularJS. The paper will further discuss the approach used for harvesting, enriching, streaming, storing, indexing, visualizing and querying a billion streaming geo-tweets.

  1. Gaze and visual search strategies of children with Asperger syndrome/high functioning autism viewing a magic trick.

    Science.gov (United States)

    Joosten, Annette; Girdler, Sonya; Albrecht, Matthew A; Horlin, Chiara; Falkmer, Marita; Leung, Denise; Ordqvist, Anna; Fleischer, Håkan; Falkmer, Torbjörn

    2016-01-01

    To examine visual search patterns and strategies used by children with and without Asperger syndrome/high functioning autism (AS/HFA) while watching a magic trick. Limited responsivity to gaze cues is hypothesised to contribute to social deficits in children with AS/HFA. Twenty-one children with AS/HFA and 31 matched peers viewed a video of a gaze-cued magic trick twice. Between the viewings, they were informed about how the trick was performed. Participants' eye movements were recorded using a head-mounted eye-tracker. Children with AS/HFA looked less frequently and had shorter fixation on the magician's direct and averted gazes during both viewings and more frequently at not gaze-cued objects and on areas outside the magician's face. After being informed of how the trick was conducted, both groups made fewer fixations on gaze-cued objects and direct gaze. Information may enhance effective visual strategies in children with and without AS/HFA.

  2. Distinct neural networks for target feature versus dimension changes in visual search, as revealed by EEG and fMRI.

    Science.gov (United States)

    Becker, Stefanie I; Grubert, Anna; Dux, Paul E

    2014-11-15

    In visual search, responses are slowed, from one trial to the next, both when the target dimension changes (e.g., from a color target to a size target) and when the target feature changes (e.g., from a red target to a green target) relative to being repeated across trials. The present study examined whether such feature and dimension switch costs can be attributed to the same underlying mechanism(s). Contrary to this contention, an EEG study showed that feature changes influenced visual selection of the target (i.e., delayed N2pc onset), whereas dimension changes influenced the later process of response selection (i.e., delayed s-LRP onset). An fMRI study provided convergent evidence for the two-system view: Compared with repetitions, feature changes led to increased activation in the occipital cortex, and superior and inferior parietal lobules, which have been implicated in spatial attention. By contrast, dimension changes led to activation of a fronto-posterior network that is primarily linked with response selection (i.e., pre-motor cortex, supplementary motor area and frontal areas). Taken together, the results suggest that feature and dimension switch costs are based on different processes. Specifically, whereas target feature changes delay attention shifts to the target, target dimension changes interfere with later response selection operations. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  3. Effects of Symbol Brightness Cueing on Attention During a Visual Search of a Cockpit Display of Traffic Information

    Science.gov (United States)

    Johnson, Walter W.; Liao, Min-Ju; Granada, Stacie

    2003-01-01

    This study investigated visual search performance for target aircraft symbols on a Cockpit Display of Traffic Information (CDTI). Of primary interest was the influence of target brightness (intensity) and highlighting validity (search directions) on the ability to detect a target aircraft among distractor aircraft. Target aircraft were distinguished by an airspace course that conflicted with Ownship (that is, the participant's aircraft). The display could present all (homogeneous) bright aircraft, all (homogeneous) dim aircraft, or mixed bright and dim aircraft, with the target aircraft being either bright or dim. In the mixed intensity condition, participants may or may not have been instructed whether the target was bright or dim. Results indicated that highlighting validity facilitated better detection times. However, instead of bright targets being detected faster, dim targets were found to be detected more slowly in the mixed intensity display than in the homogeneous display. This relative slowness may be due to a delay in confirming the dim aircraft to be a target when it it was among brighter distractor aircraft. This hypothesis will be tested in future research. Funding for this work was provided by the Advanced Air Transportation Technologies Project of NASA's Airspace Operation Systems Program.

  4. Image Size Influences Visual Search and Perception of Hemorrhages When Reading Cranial CT: An Eye-Tracking Study.

    Science.gov (United States)

    Venjakob, Antje C; Marnitz, Tim; Phillips, Peter; Mello-Thoms, Claudia R

    2016-05-01

    The aim of this study was to explore reader gaze, performance, and preference during interpretation of cranial computed tomography (cCT) in stack mode at two different sizes. Digital display of medical images allows for the manipulation of many imaging factors, like image size, by the radiologists, yet it is often not known what display parameters better suit human perception. Twenty-one radiologists provided informed consent to be eye tracked while reading 20 cCT cases. Half of these cases were presented at a size of 14 × 14 cm (512 × 512 pixels), half at 28 × 28 cm (1,024 × 1,024 pixels). Visual search, performance, and preference for the two image sizes were assessed. When reading small images, significantly fewer, but longer, fixations were observed, and these fixations covered significantly more slices. Time to first fixation of true positive findings was faster in small images, but dwell time on true findings was longer. Readers made more false positive decisions in small images, but no overall difference in either jackknife alternative free-response receiver operating characteristic or reading time was found. Overall performance is not affected by image size. However, small-stack-mode cCT images may better support the use of motion perception and acquiring an overview, whereas large-stack-mode cCT images seem better suited for detailed analyses. Subjective and eye-tracking data suggest that image size influences how images are searched and that different search strategies might be beneficial under different circumstances. © 2016, Human Factors and Ergonomics Society.

  5. Collinear masking effect in visual search is independent of perceptual salience.

    Science.gov (United States)

    Jingling, Li; Lu, Yi-Hui; Cheng, Miao; Tseng, Chia-Huei

    2017-07-01

    Searching for a target in a salient region should be easier than looking for one in a nonsalient region. However, we previously discovered a contradictory phenomenon in which a local target in a salient structure was more difficult to find than one in the background. The salient structure was constructed of orientation singletons aligned to each other to form a collinear structure. In the present study, we undertake to determine whether such a masking effect was a result of salience competition between a global structure and the local target. In the first 3 experiments, we increased the salience value of the local target with the hope of adding to its competitive advantage and eventually eliminating the masking effect; nevertheless, the masking effect persisted. In an additional 2 experiments, we reduced salience of the global collinear structure by altering the orientation of the background bars and the masking effect still emerged. Our salience manipulations were validated by a controlled condition in which the global structure was grouped noncollinearly. In this case, local target salience increase (e.g., onset) or global distractor salience reduction (e.g., randomized flanking orientations) effectively removed the facilitation effect of the noncollinear structure. Our data suggest that salience competition is unlikely to explain the collinear masking effect, and other mechanisms such as contour integration, border formation, or the crowding effect may be prospective candidates for further investigation.

  6. The control of single-colour and multiple-colour visual search by attentional templates in working memory and in long-term memory

    OpenAIRE

    Grubert, Anna; Carlisle, N.; Eimer, Martin

    2016-01-01

    The question whether target selection in visual search can be effectively controlled by simultaneous attentional templates for multiple features is still under dispute. We investigated whether multiple-colour attentional guidance is possible when target colours remain constant and can thus be represented in long-term memory but not when they change frequently and have to be held in working memory. Participants searched for one, two, or three possible target colours that were specified by cue ...

  7. Visual Foraging With Fingers and Eye Gaze

    Directory of Open Access Journals (Sweden)

    Ómar I. Jóhannesson

    2016-03-01

    Full Text Available A popular model of the function of selective visual attention involves search where a single target is to be found among distractors. For many scenarios, a more realistic model involves search for multiple targets of various types, since natural tasks typically do not involve a single target. Here we present results from a novel multiple-target foraging paradigm. We compare finger foraging where observers cancel a set of predesignated targets by tapping them, to gaze foraging where observers cancel items by fixating them for 100 ms. During finger foraging, for most observers, there was a large difference between foraging based on a single feature, where observers switch easily between target types, and foraging based on a conjunction of features where observers tended to stick to one target type. The pattern was notably different during gaze foraging where these condition differences were smaller. Two conclusions follow: (a The fact that a sizeable number of observers (in particular during gaze foraging had little trouble switching between different target types raises challenges for many prominent theoretical accounts of visual attention and working memory. (b While caveats must be noted for the comparison of gaze and finger foraging, the results suggest that selection mechanisms for gaze and pointing have different operational constraints.

  8. Involuntary top-down control by search-irrelevant features: Visual working memory biases attention in an object-based manner.

    Science.gov (United States)

    Foerster, Rebecca M; Schneider, Werner X

    2018-03-01

    Many everyday tasks involve successive visual-search episodes with changing targets. Converging evidence suggests that these targets are retained in visual working memory (VWM) and bias attention from there. It is unknown whether all or only search-relevant features of a VWM template bias attention during search. Bias signals might be configured exclusively to task-relevant features so that only search-relevant features bias attention. Alternatively, VWM might maintain objects in the form of bound features. Then, all template features will bias attention in an object-based manner, so that biasing effects are ranked by feature relevance. Here, we investigated whether search-irrelevant VWM template features bias attention. Participants had to saccade to a target opposite a distractor. A colored cue depicted the target prior to each search trial. The target was predefined only by its identity, while its color was irrelevant. When target and cue matched not only in identity (search-relevant) but also in color (search-irrelevant), saccades went more often and faster directly to the target than without any color match (Experiment 1). When introducing a cue-distractor color match (Experiment 2), direct target saccades were most likely when target and cue matched in the search-irrelevant color and least likely in case of a cue-distractor color match. When cue and target were never colored the same (Experiment 3), cue-colored distractors still captured the eyes more often than different-colored distractors despite color being search-irrelevant. As participants were informed about the misleading color, the result argues against a strategical and voluntary usage of color. Instead, search-irrelevant features biased attention obligatorily arguing for involuntary top-down control by object-based VWM templates. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Uploading, Searching and Visualizing of Paleomagnetic and Rock Magnetic Data in the Online MagIC Database

    Science.gov (United States)

    Minnett, R.; Koppers, A.; Tauxe, L.; Constable, C.; Donadini, F.

    2007-12-01

    The Magnetics Information Consortium (MagIC) is commissioned to implement and maintain an online portal to a relational database populated by both rock and paleomagnetic data. The goal of MagIC is to archive all available measurements and derived properties from paleomagnetic studies of directions and intensities, and for rock magnetic experiments (hysteresis, remanence, susceptibility, anisotropy). MagIC is hosted under EarthRef.org at http://earthref.org/MAGIC/ and will soon implement two search nodes, one for paleomagnetism and one for rock magnetism. Currently the PMAG node is operational. Both nodes provide query building based on location, reference, methods applied, material type and geological age, as well as a visual map interface to browse and select locations. Users can also browse the database by data type or by data compilation to view all contributions associated with well known earlier collections like PINT, GMPDB or PSVRL. The query result set is displayed in a digestible tabular format allowing the user to descend from locations to sites, samples, specimens and measurements. At each stage, the result set can be saved and, where appropriate, can be visualized by plotting global location maps, equal area, XY, age, and depth plots, or typical Zijderveld, hysteresis, magnetization and remanence diagrams. User contributions to the MagIC database are critical to achieving a useful research tool. We have developed a standard data and metadata template (version 2.3) that can be used to format and upload all data at the time of publication in Earth Science journals. Software tools are provided to facilitate population of these templates within Microsoft Excel. These tools allow for the import/export of text files and provide advanced functionality to manage and edit the data, and to perform various internal checks to maintain data integrity and prepare for uploading. The MagIC Contribution Wizard at http://earthref.org/MAGIC/upload.htm executes the upload

  10. Functional interaction between right parietal and bilateral frontal cortices during visual search tasks revealed using functional magnetic imaging and transcranial direct current stimulation.

    Directory of Open Access Journals (Sweden)

    Amanda Ellison

    Full Text Available The existence of a network of brain regions which are activated when one undertakes a difficult visual search task is well established. Two primary nodes on this network are right posterior parietal cortex (rPPC and right frontal eye fields. Both have been shown to be involved in the orientation of attention, but the contingency that the activity of one of these areas has on the other is less clear. We sought to investigate this question by using transcranial direct current stimulation (tDCS to selectively decrease activity in rPPC and then asking participants to perform a visual search task whilst undergoing functional magnetic resonance imaging. Comparison with a condition in which sham tDCS was applied revealed that cathodal tDCS over rPPC causes a selective bilateral decrease in frontal activity when performing a visual search task. This result demonstrates for the first time that premotor regions within the frontal lobe and rPPC are not only necessary to carry out a visual search task, but that they work together to bring about normal function.

  11. The influence of action video game playing on eye movement behaviour during visual search in abstract, in-game and natural scenes.

    Science.gov (United States)

    Azizi, Elham; Abel, Larry A; Stainer, Matthew J

    2017-02-01

    Action game playing has been associated with several improvements in visual attention tasks. However, it is not clear how such changes might influence the way we overtly select information from our visual world (i.e. eye movements). We examined whether action-video-game training changed eye movement behaviour in a series of visual search tasks including conjunctive search (relatively abstracted from natural behaviour), game-related search, and more naturalistic scene search. Forty nongamers were trained in either an action first-person shooter game or a card game (control) for 10 hours. As a further control, we recorded eye movements of 20 experienced action gamers on the same tasks. The results did not show any change in duration of fixations or saccade amplitude either from before to after the training or between all nongamers (pretraining) and experienced action gamers. However, we observed a change in search strategy, reflected by a reduction in the vertical distribution of fixations for the game-related search task in the action-game-trained group. This might suggest learning the likely distribution of targets. In other words, game training only skilled participants to search game images for targets important to the game, with no indication of transfer to the more natural scene search. Taken together, these results suggest no modification in overt allocation of attention. Either the skills that can be trained with action gaming are not powerful enough to influence information selection through eye movements, or action-game-learned skills are not used when deciding where to move the eyes.

  12. Face Recognition and Visual Search Strategies in Autism Spectrum Disorders: Amending and Extending a Recent Review by Weigelt et al.

    Directory of Open Access Journals (Sweden)

    Julia Tang

    Full Text Available The purpose of this review was to build upon a recent review by Weigelt et al. which examined visual search strategies and face identification between individuals with autism spectrum disorders (ASD and typically developing peers. Seven databases, CINAHL Plus, EMBASE, ERIC, Medline, Proquest, PsychInfo and PubMed were used to locate published scientific studies matching our inclusion criteria. A total of 28 articles not included in Weigelt et al. met criteria for inclusion into this systematic review. Of these 28 studies, 16 were available and met criteria at the time of the previous review, but were mistakenly excluded; and twelve were recently published. Weigelt et al. found quantitative, but not qualitative, differences in face identification in individuals with ASD. In contrast, the current systematic review found both qualitative and quantitative differences in face identification between individuals with and without ASD. There is a large inconsistency in findings across the eye tracking and neurobiological studies reviewed. Recommendations for future research in face recognition in ASD were discussed.

  13. You look familiar, but I don’t care: Lure rejection in hybrid visual and memory search is not based on familiarity

    Science.gov (United States)

    Wolfe, Jeremy M.; Boettcher, Sage E. P.; Josephs, Emilie L.; Cunningham, Corbin A.; Drew, Trafton

    2015-01-01

    In “hybrid” search tasks, observers hold multiple possible targets in memory while searching for those targets amongst distractor items in visual displays. Wolfe (2012) found that, if the target set is held constant over a block of trials, RTs in such tasks were a linear function of the number of items in the visual display and a linear function of the log of the number of items held in memory. However, in such tasks, the targets can become far more familiar than the distractors. Does this “familiarity” – operationalized here as the frequency and recency with which an item has appeared – influence performance in hybrid tasks In Experiment 1, we compared searches where distractors appeared with the same frequency as the targets to searches where all distractors were novel. Distractor familiarity did not have any reliable effect on search. In Experiment 2, most distractors were novel but some critical distractors were as common as the targets while others were 4× more common. Familiar distractors did not produce false alarm errors, though they did slightly increase response times (RTs). In Experiment 3, observers successfully searched for the new, unfamiliar item among distractors that, in many cases, had been seen only once before. We conclude that when the memory set is held constant for many trials, item familiarity alone does not cause observers to mistakenly confuse target with distractors. PMID:26191615

  14. The Magnetics Information Consortium (MagIC) Online Database: Uploading, Searching and Visualizing Paleomagnetic and Rock Magnetic Data

    Science.gov (United States)

    Minnett, R.; Koppers, A.; Tauxe, L.; Constable, C.; Pisarevsky, S. A.; Jackson, M.; Solheid, P.; Banerjee, S.; Johnson, C.

    2006-12-01

    The Magnetics Information Consortium (MagIC) is commissioned to implement and maintain an online portal to a relational database populated by both rock and paleomagnetic data. The goal of MagIC is to archive all measurements and the derived properties for studies of paleomagnetic directions (inclination, declination) and intensities, and for rock magnetic experiments (hysteresis, remanence, susceptibility, anisotropy). MagIC is hosted under EarthRef.org at http://earthref.org/MAGIC/ and has two search nodes, one for paleomagnetism and one for rock magnetism. Both nodes provide query building based on location, reference, methods applied, material type and geological age, as well as a visual map interface to browse and select locations. The query result set is displayed in a digestible tabular format allowing the user to descend through hierarchical levels such as from locations to sites, samples, specimens, and measurements. At each stage, the result set can be saved and, if supported by the data, can be visualized by plotting global location maps, equal area plots, or typical Zijderveld, hysteresis, and various magnetization and remanence diagrams. User contributions to the MagIC database are critical to achieving a useful research tool. We have developed a standard data and metadata template (Version 2.1) that can be used to format and upload all data at the time of publication in Earth Science journals. Software tools are provided to facilitate population of these templates within Microsoft Excel. These tools allow for the import/export of text files and provide advanced functionality to manage and edit the data, and to perform various internal checks to maintain data integrity and prepare for uploading. The MagIC Contribution Wizard at http://earthref.org/MAGIC/upload.htm executes the upload and takes only a few minutes to process several thousand data records. The standardized MagIC template files are stored in the digital archives of EarthRef.org where they

  15. Dual Target Search is Neither Purely Simultaneous nor Purely Successive.

    Science.gov (United States)

    Cave, Kyle R; Menneer, Tamaryn; Nomani, Mohammad S; Stroud, Michael J; Donnelly, Nick

    2017-08-31

    Previous research shows that visual search for two different targets is less efficient than search for a single target. Stroud, Menneer, Cave and Donnelly (2012) concluded that two target colours are represented separately based on modeling the fixation patterns. Although those analyses provide evidence for two separate target representations, they do not show whether participants search simultaneously for both targets, or first search for one target and then the other. Some studies suggest that multiple target representations are simultaneously active, while others indicate that search can be voluntarily simultaneous, or switching, or a mixture of both. Stroud et al.'s participants were not explicitly instructed to use any particular strategy. These data were revisited to determine which strategy was employed. Each fixated item was categorised according to whether its colour was more similar to one target or the other. Once an item similar to one target is fixated, the next fixated item is more likely to be similar to that target than the other, showing that at a given moment during search, one target is generally favoured. However, the search for one target is not completed before search for the other begins. Instead, there are often short runs of one or two fixations to distractors similar to one target, with each run followed by a switch to the other target. Thus, the results suggest that one target is more highly weighted than the other at any given time, but not to the extent that search is purely successive.

  16. Visual Search and the Aging Brain: Discerning the Effects of Age-related Brain Volume Shrinkage on Alertness, Feature Binding, and Attentional Control

    Science.gov (United States)

    Müller-Oehring, Eva M.; Schulte, Tilman; Rohlfing, Torsten; Pfefferbaum, Adolf; Sullivan, Edith V.

    2013-01-01

    OBJECTIVE Decline in visuospatial abilities with advancing age has been attributed to a demise of bottom-up and top-down functions involving sensory processing, selective attention, and executive control. These functions may be differentially affected by age-related volume shrinkage of subcortical and cortical nodes subserving the dorsal and ventral processing streams and the corpus callosum mediating interhemispheric information exchange. METHOD 55 healthy adults (25–84 years) underwent structural MRI and performed a visual search task to test perceptual and attentional demands by combining feature-conjunction searches with ‘gestalt’ grouping and attentional cueing paradigms. RESULTS Poorer conjunction, but not feature, search performance was related to older age and volume shrinkage of nodes in the dorsolateral processing stream. When displays allowed perceptual grouping through distractor homogeneity, poorer conjunction-search performance correlated with smaller ventrolateral prefrontal cortical and callosal volumes. An alerting cue attenuated age effects on conjunction search, and the alertness benefit was associated with thalamic, callosal, and temporal cortex volumes. CONCLUSION Our results indicate that older adults can capitalize on early parallel stages of visual information processing, whereas age-related limitations arise at later serial processing stages requiring self-guided selective attention and executive control. These limitations are explained in part by age-related brain volume shrinkage and can be mitigated by external cues. PMID:23356596

  17. Eyetracking Reveals Aberrant Visual Search During Confrontation Naming of Alzheimer’s Disease and Primary Progressive Aphasia

    Directory of Open Access Journals (Sweden)

    Ashley Bauer

    2015-04-01

    .41, SD = 1.94 significantly less than controls (M = 8.22, SD = 1.16 [t(48 = 16.07, p<.01, d = 4.2]. Patients also showed significantly delayed entry times to gaze at the target AOIs (M = 3652.11 ms, SD = 3900.30 relative to controls (M = 712.56 ms, SD = 442.00 [t(46 = -5.44, p<.01, d = 0.75]. Discussion Neurotypical adults show a highly efficient visual search pattern, fixating rapidly on one key semantic feature (e.g., eyes of a face prior to naming. In contrast, patients often do not look to the same key feature or show significantly delayed entry times to those features. These results are consistent with the claim that patients with AD and PPA experience reduced top-down support for visual search during confrontation naming. These findings suggest that the locus of anomia in AD and the temporal lobe variants of PPA lies within the degraded semantic systems.

  18. Visual search performance in children rated as good or poor attenders: the differential impact of DAT1 genotype, IQ, and chronological age.

    Science.gov (United States)

    Cornish, K M; Wilding, J M; Hollis, C

    2008-03-01

    Attention-deficit/hyperactivity disorder (ADHD) is characterized by poor attention to detail, poor attention maintenance, and variability throughout task performance. The authors used a quantitative trait loci approach to assess the association between the dopamine transporter (DAT1) high-risk genotype, cognitive performance (visual search and vigilance), and ADHD symptoms in a community sample of boys 6-11 years of age. The potential confounding effects of IQ and chronological age were also investigated. Results demonstrate that accuracy in target detection, not speed, distinguishes poor attenders from good attenders. The authors speculate that the measure of performance (e.g., time and false alarms) may be critical in detecting attentional weaknesses. In contrast, DAT1 gene, known to be associated with the behavioral symptoms of ADHD, was unrelated to visual search or vigilance performance, although it was related to ADHD symptoms.

  19. Different target-discrimination times can be followed by the same saccade-initiation timing in different stimulus conditions during visual searches

    Science.gov (United States)

    Tanaka, Tomohiro; Nishida, Satoshi

    2015-01-01

    The neuronal processes that underlie visual searches can be divided into two stages: target discrimination and saccade preparation/generation. This predicts that the length of time of the prediscrimination stage varies according to the search difficulty across different stimulus conditions, whereas the length of the latter postdiscrimination stage is stimulus invariant. However, recent studies have suggested that the length of the postdiscrimination interval changes with different stimulus conditions. To address whether and how the visual stimulus affects determination of the postdiscrimination interval, we recorded single-neuron activity in the lateral intraparietal area (LIP) when monkeys (Macaca fuscata) performed a color-singleton search involving four stimulus conditions that differed regarding luminance (Bright vs. Dim) and target-distractor color similarity (Easy vs. Difficult). We specifically focused on comparing activities between the Bright-Difficult and Dim-Easy conditions, in which the visual stimuli were considerably different, but the mean reaction times were indistinguishable. This allowed us to examine the neuronal activity when the difference in the degree of search speed between different stimulus conditions was minimal. We found that not only prediscrimination but also postdiscrimination intervals varied across stimulus conditions: the postdiscrimination interval was longer in the Dim-Easy condition than in the Bright-Difficult condition. Further analysis revealed that the postdiscrimination interval might vary with stimulus luminance. A computer simulation using an accumulation-to-threshold model suggested that the luminance-related difference in visual response strength at discrimination time could be the cause of different postdiscrimination intervals. PMID:25995344

  20. Superfund TIO videos. Set B. Basics of administrative law, and prp search process: PRP search, information exchange and access. Part 3. Audio-Visual

    International Nuclear Information System (INIS)

    1990-01-01

    The videotape is divided into two sections. Section 1 identifies the various types of administrative hearings, including quasi-legislative, quasi-judicial, and hybrid types. Section 2 provides an overview of the PRP search process; explains how and when to issue Section 104(e) letters and administrative subpoenas; outlines the enforcement authorities available in cases of non-compliance; and describes the types of information that can be released to PRPs

  1. Ahead of the game : taking their cue from the gaming industry, visualization firms speed search for oil

    International Nuclear Information System (INIS)

    Smith, M.

    2007-01-01

    The video gaming industry has been the driver for sophisticated new memory and computation capabilities when it comes to developing the latest in visualization technology used by the oil and gas sector. A broad commercial market drives the entire graphics revolution forward for the benefit of all, including petroleum exploration companies. This article presented new visualization systems that have been deployed worldwide by companies as Sun Valley, Landmark, Panoram, Halliburton and TouchTable Inc. Desktop visualization displays are getting larger, with better detail, resolution and less compressed data, making them easier on the user with less scrolling, less zooming and no switching from screen to screen. It was noted that with visualization technology, it is important to preserve resolution when viewing seismic data, particularly in the z-axis. However, the relatively small oil industry market is not big enough to provide the driver necessary to move projector technology forward very quickly. A changeover from analog to digital stereoscopic projection technology is one of the changes that has occurred. Digital light processing provides a brighter, clearer picture with better resolution, colour accuracy and stability. It was noted that the greatest advancement is the size of processing power which enables visualization in very large format, including tabletop interfaces and visualization rooms that provide wall-size high resolution or theatre-scale visualization. It was concluded that geologists, geophysicists, geocelluar modelers and petrophysicists can prove the value of visualization rooms when planning wells. 3 figs

  2. On the interplay between working memory consolidation and attentional selection in controlling conscious access : Parallel processing at a cost-a comment on 'The interplay of attention and consciousness in visual search, attentional blink and working memory consolidation'

    NARCIS (Netherlands)

    Wyble, Brad; Bowman, Howard; Nieuwenstein, Mark

    On the interplay between working memory consolidation and attentional selection in controlling conscious access: parallel processing at a cost-a comment on 'The interplay of attention and consciousness in visual search, attentional blink and working memory consolidation'

  3. Happy eating: the single target implicit association test predicts overeating after positive emotions.

    Science.gov (United States)

    Bongers, Peggy; Jansen, Anita; Houben, Katrijn; Roefs, Anne

    2013-08-01

    For many years, questionnaires have been considered the standard when examining emotional eating behavior. However, recently, some controversy has arisen about these questionnaires, and their usefulness in identifying emotional eaters has been questioned. The current study aimed to investigate the Single Target Implicit Association Test (ST-IAT) as a measure of emotional eating. Two ST-IATs (assessing food-positive and food-negative associations respectively) and the Dutch Eating Behaviour Questionnaire (DEBQ) were compared in undergraduate students. A positive, negative or neutral mood was induced by means of a film clip, and milkshake consumption was measured during and after the mood induction. It was hypothesized that participants with strong emotion-food associations on the ST-IATs (i.e., IAT-emotional eaters) would consume more food in the emotion induction condition corresponding to that emotion, as compared to those with weak emotion-food associations as well as to those in the neutral condition. Participants who scored high on both the positive and negative ST-IATs ate more during a positive mood induction than during a negative mood induction. This effect did not extend to milkshake consumption after the mood induction procedure. In addition, IAT-positive emotional eaters consumed more food than IAT-non-emotional eaters. No effects of the DEBQ on milkshake consumption were found. It is concluded that the ST-IAT has potential as a measure of emotional eating. © 2013 Elsevier Ltd. All rights reserved.

  4. Honeybees (Apis mellifera exhibit flexible visual search strategies for vertical targets presented at various heights [v2; ref status: indexed, http://f1000r.es/51p

    Directory of Open Access Journals (Sweden)

    Linde Morawetz

    2015-02-01

    Full Text Available When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can increase their detection ability of objects in search scenarios when targets appear frequently or exclusively in the dorsal area of the visual field. We trained individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the experimental phase, but bees increased their search performance significantly after a few foraging bouts: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target’s position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target’s appearance and adapt their search strategy accordingly. A variety of possible mechanisms underlying this behavioural adaptation, for example spatial attention, are discussed.

  5. The effect of items in working memory on the deployment of attention and the eyes during visual search

    NARCIS (Netherlands)

    Houtkamp, R.; Roelfsema, P. R.

    2006-01-01

    Paying attention to an object facilitates its storage in working memory. The authors investigate whether the opposite is also true: whether items in working memory influence the deployment of attention. Participants performed a search for a prespecified target while they held another item in working

  6. Psychophysics in a Web browser? Comparing response times collected with JavaScript and Psychophysics Toolbox in a visual search task.

    Science.gov (United States)

    de Leeuw, Joshua R; Motz, Benjamin A

    2016-03-01

    Behavioral researchers are increasingly using Web-based software such as JavaScript to conduct response time experiments. Although there has been some research on the accuracy and reliability of response time measurements collected using JavaScript, it remains unclear how well this method performs relative to standard laboratory software in psychologically relevant experimental manipulations. Here we present results from a visual search experiment in which we measured response time distributions with both Psychophysics Toolbox (PTB) and JavaScript. We developed a methodology that allowed us to simultaneously run the visual search experiment with both systems, interleaving trials between two independent computers, thus minimizing the effects of factors other than the experimental software. The response times measured by JavaScript were approximately 25 ms longer than those measured by PTB. However, we found no reliable difference in the variability of the distributions related to the software, and both software packages were equally sensitive to changes in the response times as a result of the experimental manipulations. We concluded that JavaScript is a suitable tool for measuring response times in behavioral research.

  7. Visual paired-associate learning: in search of material-specific effects in adult patients who have undergone temporal lobectomy.

    Science.gov (United States)

    Smith, Mary Lou; Bigel, Marla; Miller, Laurie A

    2011-02-01

    The mesial temporal lobes are important for learning arbitrary associations. It has previously been demonstrated that left mesial temporal structures are involved in learning word pairs, but it is not yet known whether comparable lesions in the right temporal lobe impair visually mediated associative learning. Patients who had undergone left (n=16) or right (n=18) temporal lobectomy for relief of intractable epilepsy and healthy controls (n=13) were administered two paired-associate learning tasks assessing their learning and memory of pairs of abstract designs or pairs of symbols in unique locations. Both patient groups had deficits in learning the designs, but only the right temporal group was impaired in recognition. For the symbol location task, differences were not found in learning, but again a recognition deficit was found for the right temporal group. The findings implicate the mesial temporal structures in relational learning. They support a material-specific effect for recognition but not for learning and recall of arbitrary visual and visual-spatial associative information. Copyright © 2010 Elsevier Inc. All rights reserved.

  8. Neural circuits of eye movements during performance of the visual exploration task, which is similar to the responsive search score task, in schizophrenia patients and normal subjects

    International Nuclear Information System (INIS)

    Nemoto, Yasundo; Matsuda, Tetsuya; Matsuura, Masato

    2004-01-01

    Abnormal exploratory eye movements have been studied as a biological marker for schizophrenia. Using functional MRI (fMRI), we investigated brain activations of 12 healthy and 8 schizophrenic subjects during performance of a visual exploration task that is similar to the responsive search score task to clarify the neural basis of the abnormal exploratory eye movement. Performance data, such as the number of eye movements, the reaction time, and the percentage of correct answers showed no significant differences between the two groups. Only the normal subjects showed activations at the bilateral thalamus and the left anterior medial frontal cortex during the visual exploration tasks. In contrast, only the schizophrenic subjects showed activations at the right anterior cingulate gyms during the same tasks. The activation at the different locations between the two groups, the left anterior medial frontal cortex in normal subjects and the right anterior cingulate gyrus in schizophrenia subjects, was explained by the feature of the visual tasks. Hypoactivation at the bilateral thalamus supports a dysfunctional filtering theory of schizophrenia. (author)

  9. The effects of memory load and stimulus relevance on the EEG during a visual selective memory search task: an ERP and ERD/ERS study.

    Science.gov (United States)

    Gomarus, H Karin; Althaus, Monika; Wijers, Albertus A; Minderaa, Ruud B

    2006-04-01

    Psychophysiological correlates of selective attention and working memory were investigated in a group of 18 healthy children using a visually presented selective memory search task. Subjects had to memorize one (load1) or 3 (load3) letters (memory set) and search for these among a recognition set consisting of 4 letters only if the letters appeared in the correct (relevant) color. Event-related potentials (ERPs) as well as alpha and theta event-related synchronization and desynchronization (ERD/ERS) were derived from the EEG that was recorded during the task. In the ERP to the memory set, a prolonged load-related positivity was found. In response to the recognition set, effects of relevance were manifested in an early frontal positivity and a later frontal negativity. Effects of load were found in a search-related negativity within the attended category and a suppression of the P3-amplitude. Theta ERS was most pronounced for the most difficult task condition during the recognition set, whereas alpha ERD showed a load-effect only during memorization. The manipulation of stimulus relevance and memory load affected both ERP components and ERD/ERS. The present paradigm may supply a useful method for studying processes of selective attention and working memory and can be used to examine group differences between healthy controls and children showing psychopathology.

  10. The Control of Single-color and Multiple-color Visual Search by Attentional Templates in Working Memory and in Long-term Memory.

    Science.gov (United States)

    Grubert, Anna; Carlisle, Nancy B; Eimer, Martin

    2016-12-01

    The question whether target selection in visual search can be effectively controlled by simultaneous attentional templates for multiple features is still under dispute. We investigated whether multiple-color attentional guidance is possible when target colors remain constant and can thus be represented in long-term memory but not when they change frequently and have to be held in working memory. Participants searched for one, two, or three possible target colors that were specified by cue displays at the start of each trial. In constant-color blocks, the same colors remained task-relevant throughout. In variable-color blocks, target colors changed between trials. The contralateral delay activity (CDA) to cue displays increased in amplitude as a function of color memory load in variable-color blocks, which indicates that cued target colors were held in working memory. In constant-color blocks, the CDA was much smaller, suggesting that color representations were primarily stored in long-term memory. N2pc components to targets were measured as a marker of attentional target selection. Target N2pcs were attenuated and delayed during multiple-color search, demonstrating less efficient attentional deployment to color-defined target objects relative to single-color search. Importantly, these costs were the same in constant-color and variable-color blocks. These results demonstrate that attentional guidance by multiple-feature as compared with single-feature templates is less efficient both when target features remain constant and can be represented in long-term memory and when they change across trials and therefore have to be maintained in working memory.

  11. From Capture to Inhibition: How does Irrelevant Information Influence Visual Search? Evidence from a Spatial Cuing Paradigm.

    Science.gov (United States)

    Mertes, Christine; Wascher, Edmund; Schneider, Daniel

    2016-01-01

    Even though information is spatially and temporally irrelevant, it can influence the processing of subsequent information. The present study used a spatial cuing paradigm to investigate the origins of this persisting influence by means of event-related potentials (ERPs) of the EEG. An irrelevant color cue that was either contingent (color search) or non-contingent (shape search) on attentional sets was presented prior to a target array with different stimulus-onset asynchronies (SOA; 200, 400, 800 ms). Behavioral results indicated that color cues captured attention only when they shared target-defining properties. These same-location effects persisted over time but were pronounced when cue and target array were presented in close succession. N2 posterior contralateral (N2pc) showed that the color cue generally drew attention, but was strongest in the contingent condition. A subsequently emerging contralateral posterior positivity referred to the irrelevant cue (i.e., distractor positivity, Pd) was unaffected by the attentional set and therefore interpreted as an inhibitory process required to enable a re-direction of the attentional focus. Contralateral delay activity (CDA) was only observable in the contingent condition, indicating the transfer of spatial information into working memory and thus providing an explanation for the same-location effect for longer SOAs. Inhibition of this irrelevant information was reflected by a second contralateral positivity triggered through target presentation. The results suggest that distracting information is actively maintained when it resembles a sought-after object. However, two independent attentional processes are at work to compensate for attentional distraction: the timely inhibition of attentional capture and the active inhibition of mental representation of irrelevant information.

  12. From capture to inhibition: How does irrelevant information influence visual search? Evidence from a spatial cuing paradigm.

    Directory of Open Access Journals (Sweden)

    Christine eMertes

    2016-05-01

    Full Text Available Even though information is spatially and temporally irrelevant, it can influence the processing of subsequent information. The present study used a spatial cuing paradigm to investigate the origins of this persisting influence by means of event-related potentials (ERPs of the EEG. An irrelevant color cue that was either contingent (color search or non-contingent (shape search on attentional sets was presented prior to a target array with different stimulus-onset asynchronies (SOA; 200, 400, 800 ms. Behavioral results indicated that color cues captured attention only when they shared target-defining properties. These same-location effects persisted over time but were pronounced when cue and target array were presented in close succession. N2pc showed that the color cue generally drew attention, but was strongest in the contingent condition. A subsequently emerging contralateral posterior positivity referred to the irrelevant cue (i.e. distractor positivity; Pd was unaffected by the attentional set and therefore interpreted as an inhibitory process required to enable a re-direction of the attentional focus. CDA was only observable in the contingent condition, indicating the transfer of spatial information into working memory and thus providing an explanation for the same-location effect for longer SOAs. Inhibition of this irrelevant information was reflected by a second contralateral positivity triggered through target presentation. The results suggest that distracting information is actively maintained when it resembles a sought-after object. However, two independent attentional processes are at work to compensate for attentional distraction: The timely inhibition of attentional capture and the active inhibition of mental representation of irrelevant information.

  13. The Behavioral Effects of tDCS on Visual Search Performance Are Not Influenced by the Location of the Reference Electrode

    Directory of Open Access Journals (Sweden)

    Amanda Ellison

    2017-09-01

    Full Text Available We investigated the role of reference electrode placement (ipsilateral v contralateral frontal pole on conjunction visual search task performance when the transcranial direct current stimulation (tDCS cathode is placed over right posterior parietal cortex (rPPC and over right frontal eye fields (rFEF, both of which have been shown to be causally involved in the processing of this task using TMS. This resulted in four experimental manipulations in which sham tDCS was applied in week one followed by active tDCS the following week. Another group received sham stimulation in both sessions to investigate practice effects over 1 week in this task. Results show that there is no difference between effects seen when the anode is placed ipsi or contralaterally. Cathodal stimulation of rPPC increased search times straight after stimulation similarly for ipsi and contralateral references. This finding does not extend to rFEF stimulation. However, for both sites and both montages, practice effects as seen in the sham/sham condition were negated. This can be taken as evidence that for this task, reference placement on either frontal pole is not important, but also that care needs to be taken when contextualizing tDCS “effects” that may not be immediately apparent particularly in between-participant designs.

  14. Informatics in Radiology: What Can You See in a Single Glance and How Might This Guide Visual Search in Medical Images?

    Science.gov (United States)

    Evans, Karla; Võ, Melissa L. -H.; Jacobson, Francine L.; Wolfe, Jeremy M.

    2013-01-01

    Diagnostic accuracy for radiologists is above that expected by chance when they are exposed to a chest radiograph for only one-fifth of a second, a period too brief for more than a single voluntary eye movement. How do radiologists glean information from a first glance at an image? It is thought that this expert impression of the gestalt of an image is related to the everyday, immediate visual understanding of the gist of a scene. Several high-speed mechanisms guide our search of complex images. Guidance by basic features (such as color) requires no learning, whereas guidance by complex scene properties is learned. It is probable that both hardwired guidance by basic features and learned guidance by scene structure become part of radiologists’ expertise. Search in scenes may be best explained by a two-pathway model: Object recognition is performed via a selective pathway in which candidate targets must be individually selected for recognition. A second, nonselective pathway extracts information from global or statistical information without selecting specific objects. An appreciation of the role of nonselective processing may be particularly useful for understanding what separates novice from expert radiologists and could help establish new methods of physician training based on medical image perception. © RSNA, 2012 PMID:23104971

  15. Optimizing Persistent Random Searches

    Science.gov (United States)

    Tejedor, Vincent; Voituriez, Raphael; Bénichou, Olivier

    2012-02-01

    We consider a minimal model of persistent random searcher with a short range memory. We calculate exactly for such a searcher the mean first-passage time to a target in a bounded domain and find that it admits a nontrivial minimum as function of the persistence length. This reveals an optimal search strategy which differs markedly from the simple ballistic motion obtained in the case of Poisson distributed targets. Our results show that the distribution of targets plays a crucial role in the random search problem. In particular, in the biologically relevant cases of either a single target or regular patterns of targets, we find that, in strong contrast to repeated statements in the literature, persistent random walks with exponential distribution of excursion lengths can minimize the search time, and in that sense perform better than any Levy walk.

  16. Evaluating color deficiency simulation and daltonization methods through visual search and sample-to-match: SaMSEM and ViSDEM

    Science.gov (United States)

    Simon-Liedtke, Joschua T.; Farup, Ivar; Laeng, Bruno

    2015-01-01

    Color deficient people might be confronted with minor difficulties when navigating through daily life, for example when reading websites or media, navigating with maps, retrieving information from public transport schedules and others. Color deficiency simulation and daltonization methods have been proposed to better understand problems of color deficient individuals and to improve color displays for their use. However, it remains unclear whether these color prosthetic" methods really work and how well they improve the performance of color deficient individuals. We introduce here two methods to evaluate color deficiency simulation and daltonization methods based on behavioral experiments that are widely used in the field of psychology. Firstly, we propose a Sample-to-Match Simulation Evaluation Method (SaMSEM); secondly, we propose a Visual Search Daltonization Evaluation Method (ViSDEM). Both methods can be used to validate and allow the generalization of the simulation and daltonization methods related to color deficiency. We showed that both the response times (RT) and the accuracy of SaMSEM can be used as an indicator of the success of color deficiency simulation methods and that performance in the ViSDEM can be used as an indicator for the efficacy of color deficiency daltonization methods. In future work, we will include comparison and analysis of different color deficiency simulation and daltonization methods with the help of SaMSEM and ViSDEM.

  17. Cube search, revisited

    Science.gov (United States)

    Zhang, Xuetao; Huang, Jie; Yigit-Elliott, Serap; Rosenholtz, Ruth

    2015-01-01

    Observers can quickly search among shaded cubes for one lit from a unique direction. However, replace the cubes with similar 2-D patterns that do not appear to have a 3-D shape, and search difficulty increases. These results have challenged models of visual search and attention. We demonstrate that cube search displays differ from those with “equivalent” 2-D search items in terms of the informativeness of fairly low-level image statistics. This informativeness predicts peripheral discriminability of target-present from target-absent patches, which in turn predicts visual search performance, across a wide range of conditions. Comparing model performance on a number of classic search tasks, cube search does not appear unexpectedly easy. Easy cube search, per se, does not provide evidence for preattentive computation of 3-D scene properties. However, search asymmetries derived from rotating and/or flipping the cube search displays cannot be explained by the information in our current set of image statistics. This may merely suggest a need to modify the model's set of 2-D image statistics. Alternatively, it may be difficult cube search that provides evidence for preattentive computation of 3-D scene properties. By attributing 2-D luminance variations to a shaded 3-D shape, 3-D scene understanding may slow search for 2-D features of the target. PMID:25780063

  18. Parieto-occipital areas involved in efficient filtering in search: a time course analysis of visual marking using behavioural and functional imaging procedures

    DEFF Research Database (Denmark)

    Humphreys, Glyn W; Kyllingsbæk, Søren; Watson, Derrick G.

    2004-01-01

    . Furthermore, the reductions in reaction time across time in the preview condition varied nonlinearly with the display size, suggesting that old items were discounted from search in parallel. In Experiment 2 we examined the neural locus of this filtering effect over time, using positron emission tomography...... (PET). We show that regions of parieto-occipital cortex are selectively activated in a preview search condition relative to a detection baseline. These regions also increase in activation as the preview interval increases (and search then becomes easier), consistent with them modulating the parallel...... filtering of distractors from targets in spatial search. Interestingly, the same areas as those activated in preview search were also active in conjunction search relative to its own detection baseline. Thus these regions either modulate parallel filtering in conjunction search too, or they modulate...

  19. Effects of flicker rate, complexity, and color combinations of Chinese characters and backgrounds on visual search performance with varying flicker types.

    Science.gov (United States)

    Huang, Kuo-Chen; Lin, Rung-Tai; Wu, Chih-Fu

    2011-08-01

    This study investigated the effects of number of strokes in Chinese characters, flicker rate, flicker type, and character/background color combination on search performance. 37 participants ages 14 to 18 years were randomly assigned to each flicker-type condition. The search field contained 36 characters arranged in a 6 x 6 matrix. Participants were asked to search for the target characters among the surrounding distractors and count how many target characters were displayed in the search array. Analysis indicated that the character/background color combination significantly affected search times. The color combinations of white/purple and white/green yielded search times greater than those for black/white and black/yellow combinations. A significant effect for flicker type on search time was also identified. Rotating characters facilitated search time, compared with twinkling ones. The number of strokes and the flicker rates also had positive effects on search performances. For flicker rate, the search accuracy for 0.5 Hz was greater than that for 1.0 Hz, and the latter was also greater than that for 2.0 Hz. Results are applicable to web advertisement designs containing dynamic characters, in terms of how to best capture readers' attention by various means of dynamic character presentation.

  20. Cortical visual impairment

    OpenAIRE

    Koželj, Urša

    2013-01-01

    In this thesis we discuss cortical visual impairment, diagnosis that is in the developed world in first place, since 20 percent of children with blindness or low vision are diagnosed with it. The objectives of the thesis are to define cortical visual impairment and the definition of characters suggestive of the cortical visual impairment as well as to search for causes that affect the growing diagnosis of cortical visual impairment. There are a lot of signs of cortical visual impairment. ...

  1. Search Help

    Science.gov (United States)

    Guidance and search help resource listing examples of common queries that can be used in the Google Search Appliance search request, including examples of special characters, or query term seperators that Google Search Appliance recognizes.

  2. Exploring Visual Bookmarks and Layered Visualizations

    NARCIS (Netherlands)

    J.T. Teuben (Jan)

    2010-01-01

    textabstractCultural heritage experts are confronted with a difficult information gathering task while conducting comparison searches. Saving searches and re-examining previous work could help them to do their work. In this paper we propose a solution in which we combine visual bookmarks for saving

  3. Search for Two Categories of Target Produces Fewer Fixations to Target-Color Items

    Science.gov (United States)

    Menneer, Tamaryn; Stroud, Michael J.; Cave, Kyle R.; Li, Xingshan; Godwin, Hayward J.; Liversedge, Simon P.; Donnelly, Nick

    2012-01-01

    Searching simultaneously for metal threats (guns and knives) and improvised explosive devices (IEDs) in X-ray images is less effective than 2 independent single-target searches, 1 for metal threats and 1 for IEDs. The goals of this study were to (a) replicate this dual-target cost for categorical targets and to determine whether the cost remains…

  4. Adults with Dyslexia Exhibit Large Effects of Crowding, Increased Dependence on Cues, and Detrimental Effects of Distractors in Visual Search Tasks

    Science.gov (United States)

    Moores, Elisabeth; Cassim, Rizan; Talcott, Joel B.

    2011-01-01

    Difficulties in visual attention are increasingly being linked to dyslexia. To date, the majority of studies have inferred functionality of attention from response times to stimuli presented for an indefinite duration. However, in paradigms that use reaction times to investigate the ability to orient attention, a delayed reaction time could also…

  5. Parieto-occipital areas involved in efficient filtering in search: a time course analysis of visual marking using behavioural and functional imaging procedures

    DEFF Research Database (Denmark)

    Humphreys, Glyn W; Kyllingsbæk, Søren; Watson, Derrick G.

    2004-01-01

    Search for a colour-form conjunction target can be facilitated by presenting one set of distractors prior to the second set of distractors and the target: the preview benefit (Watson & Humphreys, 1997). The early presentation of one set of distractors enables them to be efficiently filtered from...

  6. Parieto-occipital areas involved in efficient filtering in search: a time course analysis of visual marking using behavioural and functional imaging procedures

    DEFF Research Database (Denmark)

    Humphreys, Glyn W; Kyllingsbæk, Søren; Watson, Derrick G.

    2004-01-01

    Search for a colour-form conjunction target can be facilitated by presenting one set of distractors prior to the second set of distractors and the target: the preview benefit (Watson & Humphreys, 1997). The early presentation of one set of distractors enables them to be efficiently filtered from ...

  7. The Visual System

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home >> NEI for Kids >> The Visual System Listen All ... up to 28,800 times a day! NEI Home Contact Us A-Z Site Map NEI on ...

  8. Random searching

    International Nuclear Information System (INIS)

    Shlesinger, Michael F

    2009-01-01

    There are a wide variety of searching problems from molecules seeking receptor sites to predators seeking prey. The optimal search strategy can depend on constraints on time, energy, supplies or other variables. We discuss a number of cases and especially remark on the usefulness of Levy walk search patterns when the targets of the search are scarce.

  9. Search Patterns

    CERN Document Server

    Morville, Peter

    2010-01-01

    What people are saying about Search Patterns "Search Patterns is a delight to read -- very thoughtful and thought provoking. It's the most comprehensive survey of designing effective search experiences I've seen." --Irene Au, Director of User Experience, Google "I love this book! Thanks to Peter and Jeffery, I now know that search (yes, boring old yucky who cares search) is one of the coolest ways around of looking at the world." --Dan Roam, author, The Back of the Napkin (Portfolio Hardcover) "Search Patterns is a playful guide to the practical concerns of search interface design. It cont

  10. Automated search for supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kare, J.T.

    1984-11-15

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion.

  11. Automated search for supernovae

    International Nuclear Information System (INIS)

    Kare, J.T.

    1984-01-01

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion

  12. Personalized Search

    CERN Document Server

    AUTHOR|(SzGeCERN)749939

    2015-01-01

    As the volume of electronically available information grows, relevant items become harder to find. This work presents an approach to personalizing search results in scientific publication databases. This work focuses on re-ranking search results from existing search engines like Solr or ElasticSearch. This work also includes the development of Obelix, a new recommendation system used to re-rank search results. The project was proposed and performed at CERN, using the scientific publications available on the CERN Document Server (CDS). This work experiments with re-ranking using offline and online evaluation of users and documents in CDS. The experiments conclude that the personalized search result outperform both latest first and word similarity in terms of click position in the search result for global search in CDS.

  13. Visual field

    Science.gov (United States)

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam. This is a quick and basic check of the visual field. The health care provider ...

  14. Faceted Search

    CERN Document Server

    Tunkelang, Daniel

    2009-01-01

    We live in an information age that requires us, more than ever, to represent, access, and use information. Over the last several decades, we have developed a modern science and technology for information retrieval, relentlessly pursuing the vision of a "memex" that Vannevar Bush proposed in his seminal article, "As We May Think." Faceted search plays a key role in this program. Faceted search addresses weaknesses of conventional search approaches and has emerged as a foundation for interactive information retrieval. User studies demonstrate that faceted search provides more

  15. Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  16. A Measure of Search Efficiency in a Real World Search Task

    Science.gov (United States)

    2008-12-01

    memory during visual search. Journal of Vision , 7(9), 1060. Bravo, M. J., & Farid, H. (2004). Search for a category target in clutter. Perception, 33(6...Nakano, L. (2007). Measuring visual clutter. Journal of Vision , 7(2), 1-22. Thornton, T. L. & Gilden, D. L. (2007). Parallel and serial processes in

  17. Autonomous search

    CERN Document Server

    Hamadi, Youssef; Saubion, Frédéric

    2012-01-01

    Autonomous combinatorial search (AS) represents a new field in combinatorial problem solving. Its major standpoint and originality is that it considers that problem solvers must be capable of self-improvement operations. This is the first book dedicated to AS.

  18. A Unique Role of Endogenous Visual-Spatial Attention in Rapid Processing of Multiple Targets

    Science.gov (United States)

    Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Palafox, German; Suzuki, Satoru

    2011-01-01

    Visual spatial attention can be exogenously captured by a salient stimulus or can be endogenously allocated by voluntary effort. Whether these two attention modes serve distinctive functions is debated, but for processing of single targets the literature suggests superiority of exogenous attention (it is faster acting and serves more functions).…

  19. Single Targeted Exon Mutation Creates a True Congenic Mouse for Competitive Hematopoietic Stem Cell Transplantation: The C57BL/6-CD45.1STEM Mouse

    Directory of Open Access Journals (Sweden)

    Francois E. Mercier

    2016-06-01

    Full Text Available Defining the molecular regulators of hematopoietic stem and progenitor cells (HSPCs requires in vivo functional analyses. Competitive bone marrow transplants (BMTs compare control and test HSPCs to demonstrate the functional role of a genetic change or chemical perturbation. Competitive BMT is enabled by antibodies that specifically recognize hematopoietic cells from congenic mouse strains due to variants of the cell surface protein CD45, designated CD45.1 and CD45.2. The current congenic competitor strain, B6.SJL-Ptprca Pepcb/BoyJ (CD45.1, has a substantial inherent disadvantage in competition against the C57BL/6 (CD45.2 strain, confounding experimental interpretation. Despite backcrossing, the congenic interval over which the B6.SJL-Ptprca Pepcb/BoyJ strain differs is almost 40 Mb encoding ∼300 genes. Here, we demonstrate that a single amino acid change determines the CD45.1 epitope. Further, we report on the single targeted exon mutant (STEM mouse strain, CD45.1STEM, which is functionally equivalent to CD45.2 cells in competitive BMT. This strain will permit the precise definition of functional roles for candidate genes using in vivo HSPC assays.

  20. Longterm visual associations affect attentional guidance

    NARCIS (Netherlands)

    Olivers, C.N.L.

    2011-01-01

    When observers perform a visual search task, they are assumed to adopt an attentional set for what they are looking for. The present experiment investigates the influence of long-term visual memory associations on this attentional set. On each trial, observers were asked to search a display for a

  1. Visual Culture and Visual Literacy

    Directory of Open Access Journals (Sweden)

    Sibel Onursoy

    2017-03-01

    Full Text Available Recently visual literacy gains importance in the context of understanding the rising visual culture products, thinking about them and producing these products. The purpose of this article examines the concept of visual literacy that is the relationship with visual culture depending on the literature. Visual literacy is one of the multiple literatures that emerge from the development of information and information dissemination forms. Visual literacy is an interdisciplinary concept and associated with some areas, such as graphic design, visual arts, architectural engineering, industrial product design, visual communication and media literacy. Visual culture covers every human product, so visual products that we face in everyday life and visual realities with abundant alternatives constitute our daily life itself. Sometimes, this confusing visual understanding creates a gap between contemporary cultural richness and what can be observed.

  2. Computerized Screening for Visual Stress in Children with Dyslexia

    Science.gov (United States)

    Singleton, Chris; Henderson, Lisa-Marie

    2007-01-01

    Visual stress--a condition in which unpleasant visual symptoms are experienced when reading--has been reported to be more prevalent in dyslexic individuals but at the present time the relationship between dyslexia and visual stress remains controversial. ViSS, a computerized visual stress screener that incorporates reading-like visual search, has…

  3. Análise dos padrões dos movimentos oculares em tarefas de busca visual: efeito da familiaridade e das características físicas do estímulo Analysis of the eye movement patterns in visual search tasks: effect of familiarity and stimulus features

    Directory of Open Access Journals (Sweden)

    Elizeu Coutinho de Macedo

    2007-02-01

    analyze eye movements in asymmetric visual search using the task of normal and mirrored position letters. To evaluate the effect of familiarity and stimulus features. METHODS: Eighty-three university students with normal or corrected-to-normal vision were asked to search for a letter in inverted position to the letters in a group of either normal or mirrored letters. Four types of letters were used (Z, N, E and G and the eye movements were tracked by a specialized computer-based system (eyetracking. The analyzed measurements were: reaction time, fixation number and duration, saccade distance and duration. RESULTS: All measures varied with the type of letter. Reaction time, fixation number, and saccade distance were higher when the task was to find the normal letter in a group of mirrored letters. In this condition, fixation duration was smaller. Interaction was found between familiarity and the type of letter for the reaction time, fixation number and duration. The reaction time and fixation number increased together with the stimulus complexity, with a greater increase for the normal letter target. Fixation duration, however, decreased with the complexity of the stimuli and the search condition. CONCLUSIONS: Finding a mirrored letter among normal letters proved to be easier than the contrary. The letter type also affected the performance. When the context is formed of unfamiliar complex stimuli, the fixation duration is shorter, indicating a narrower span for visual processing. Therefore, a greater number of fixations with shorter duration are needed for the unfamiliar context while less fixations with greater duration are needed for the familiar context.

  4. Visual art and visual perception

    NARCIS (Netherlands)

    Koenderink, Jan J.

    2015-01-01

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

  5. Intrinsic position uncertainty impairs overt search performance.

    Science.gov (United States)

    Semizer, Yelda; Michel, Melchi M

    2017-08-01

    Uncertainty regarding the position of the search target is a fundamental component of visual search. However, due to perceptual limitations of the human visual system, this uncertainty can arise from intrinsic, as well as extrinsic, sources. The current study sought to characterize the role of intrinsic position uncertainty (IPU) in overt visual search and to determine whether it significantly limits human search performance. After completing a preliminary detection experiment to characterize sensitivity as a function of visual field position, observers completed a search task that required localizing a Gabor target within a field of synthetic luminance noise. The search experiment included two clutter conditions designed to modulate the effect of IPU across search displays of varying set size. In the Cluttered condition, the display was tiled uniformly with feature clutter to maximize the effects of IPU. In the Uncluttered condition, the clutter at irrelevant locations was removed to attenuate the effects of IPU. Finally, we derived an IPU-constrained ideal searcher model, limited by the IPU measured in human observers. Ideal searchers were simulated based on the detection sensitivity and fixation sequences measured for individual human observers. The IPU-constrained ideal searcher predicted performance trends similar to those exhibited by the human observers. In the Uncluttered condition, performance decreased steeply as a function of increasing set size. However, in the Cluttered condition, the effect of IPU dominated and performance was approximately constant as a function of set size. Our findings suggest that IPU substantially limits overt search performance, especially in crowded displays.

  6. Early vision and visual attention

    Directory of Open Access Journals (Sweden)

    Gvozdenović Vasilije P.

    2003-01-01

    Full Text Available The question whether visual perception is spontaneous, sudden or is running through several phases, mediated by higher cognitive processes, was raised ever since the early work of Gestalt psychologists. In the early 1980s, Treisman proposed the feature integration theory of attention (FIT, based on the findings of neuroscience. Soon after publishing her theory a new scientific approach appeared investigating several visual perception phenomena. The most widely researched were the key constructs of FIT, like types of visual search and the role of the attention. The following review describes the main studies of early vision and visual attention.

  7. Flow visualization

    CERN Document Server

    Merzkirch, Wolfgang

    1974-01-01

    Flow Visualization describes the most widely used methods for visualizing flows. Flow visualization evaluates certain properties of a flow field directly accessible to visual perception. Organized into five chapters, this book first presents the methods that create a visible flow pattern that could be investigated by visual inspection, such as simple dye and density-sensitive visualization methods. It then deals with the application of electron beams and streaming birefringence. Optical methods for compressible flows, hydraulic analogy, and high-speed photography are discussed in other cha

  8. Internet Search Engines

    OpenAIRE

    Fatmaa El Zahraa Mohamed Abdou

    2004-01-01

    A general study about the internet search engines, the study deals main 7 points; the differance between search engines and search directories, components of search engines, the percentage of sites covered by search engines, cataloging of sites, the needed time for sites appearance in search engines, search capabilities, and types of search engines.

  9. Positions priming in briefly presented search arrays

    DEFF Research Database (Denmark)

    Asgeirsson, Arni Gunnar; Kristjánsson, Árni; Kyllingsbæk, Søren

    2011-01-01

    Repetition priming in visual search has been a topic of extensive research since Maljkovic & Nakayama [1994, Memory & Cognition, 22, 657-672] presented the first detailed studies of such effects. Their results showed large reductions in reaction times when target color was repeated on consecutive...... the targets are oddly colored alphanumeric characters. The effects arise at very low exposure durations and benefit accuracy at all exposure durations towards the subjects’ ceiling. We conclude that temporally constricted experimental conditions can add to our understanding priming in visual search...... pop-out search trials. Such repetition effects have since been generalized to a multitude of target attributes. Priming has primarily been investigated using self-terminating visual search paradigms, comparing differences in response times. Response accuracy has predominantly served as a control...

  10. Data visualization

    CERN Document Server

    Azzam, Tarek

    2013-01-01

    Do you communicate data and information to stakeholders? In Part 1, we introduce recent developments in the quantitative and qualitative data visualization field and provide a historical perspective on data visualization, its potential role in evaluation practice, and future directions. Part 2 delivers concrete suggestions for optimally using data visualization in evaluation, as well as suggestions for best practices in data visualization design. It focuses on specific quantitative and qualitative data visualization approaches that include data dashboards, graphic recording, and geographic information systems (GIS). Readers will get a step-by-step process for designing an effective data dashboard system for programs and organizations, and various suggestions to improve their utility.

  11. Quantized Visual Awareness

    Directory of Open Access Journals (Sweden)

    W Alexander Escobar

    2013-11-01

    Full Text Available The proposed model holds that, at its most fundamental level, visual awareness is quantized. That is to say that visual awareness arises as individual bits of awareness through the action of neural circuits with hundreds to thousands of neurons in at least the human striate cortex. Circuits with specific topologies will reproducibly result in visual awareness that correspond to basic aspects of vision like color, motion and depth. These quanta of awareness (qualia are produced by the feedforward sweep that occurs through the geniculocortical pathway but are not integrated into a conscious experience until recurrent processing from centers like V4 or V5 select the appropriate qualia being produced in V1 to create a percept. The model proposed here has the potential to shift the focus of the search for visual awareness to the level of microcircuits and these likely exist across the kingdom Animalia. Thus establishing qualia as the fundamental nature of visual awareness will not only provide a deeper understanding of awareness, but also allow for a more quantitative understanding of the evolution of visual awareness throughout the animal kingdom.

  12. Quantized visual awareness

    Science.gov (United States)

    Escobar, W. A.

    2013-01-01

    The proposed model holds that, at its most fundamental level, visual awareness is quantized. That is to say that visual awareness arises as individual bits of awareness through the action of neural circuits with hundreds to thousands of neurons in at least the human striate cortex. Circuits with specific topologies will reproducibly result in visual awareness that correspond to basic aspects of vision like color, motion, and depth. These quanta of awareness (qualia) are produced by the feedforward sweep that occurs through the geniculocortical pathway but are not integrated into a conscious experience until recurrent processing from centers like V4 or V5 select the appropriate qualia being produced in V1 to create a percept. The model proposed here has the potential to shift the focus of the search for visual awareness to the level of microcircuits and these likely exist across the kingdom Animalia. Thus establishing qualia as the fundamental nature of visual awareness will not only provide a deeper understanding of awareness, but also allow for a more quantitative understanding of the evolution of visual awareness throughout the animal kingdom. PMID:24319436

  13. Searching for IOR: Review and Results

    Directory of Open Access Journals (Sweden)

    J MacInnes

    2011-04-01

    Full Text Available Inhibition of return (IOR has been proposed as an attentional mechanism which facilitates visual search by inhibiting reorienting to previously attended spatial locations. IOR is typically measured following the removal of attention from a spatial location. Early facilitation of responses to this location at early stimulus-onset asynchrony (SOA of ∼100 – 300ms is replaced with a later and long-lasting inhibition (SOA of ∼300 – 3000ms. This inhibition has been proposed to be used by the oculomotor system to tag previously fixated locations in visual search to favour new locations over old (yet still salient locations. Indeed, slower responses to probes presented in recently fixated locations has since been demonstrated in a variety of visual search tasks, and this form of IOR has been related to the reduced likelihood of refixating the previous or penultimate search location during natural search (MacInnes and Klein, 2003. However, recent research has challenged this interpretation by suggesting that saccadic momentum facilitates forward saccades as opposed to IOR suppressing return saccades. For instance, Smith and Henderson (2010 replicated Klein and MacInnes (1999 by finding IOR in a Where's Waldo © search task, but they reanalyzed the probability distribution of saccades to provide evidence for a saccadic momentum account. This talk will provide a review of recent research outlining the evidence for IOR and saccadic momentum in natural search patterns and present new data on the distribution of saccades in complex search tasks. [Supported by BBSRC

  14. A Measure of Search Efficiency in a Real World Search Task (PREPRINT)

    Science.gov (United States)

    2009-02-16

    2007). Local spatial layout consistency affects strategies but not memory during visual search. Journal of Vision , 7(9), 1060. Bravo, M. J., & Farid, H...Factors in Computing Systems, Portland, OR. Rosenholtz, R, Li, Y., & Nakano, L. (2007). Measuring visual clutter. Journal of Vision , 7(2), 1-22

  15. Earthdata Search: Scaling, Assessing and Improving Relevancy

    Science.gov (United States)

    Reese, Mark

    2016-01-01

    NASA's Earthdata Search (https:search.earthdata.nasa.gov) application allows users to search, discover, visualize, and access NASA and international interagency data about the Earth. As a client to NASA's Common Metadata Repository (CMR), its catalog of data collections grew 700 in late 2015. This massive expansion brought improved search and discovery to the forefront of the client's usability needs. During this talk, we will give a brief overview of the application, the challenges that arose during this period of growth, the metrics-driven way we addressed them, and the latest outcomes.

  16. The Computational Anatomy of Visual Neglect.

    Science.gov (United States)

    Parr, Thomas; Friston, Karl J

    2018-02-01

    Visual neglect is a debilitating neuropsychological phenomenon that has many clinical implications and-in cognitive neuroscience-offers an important lesion deficit model. In this article, we describe a computational model of visual neglect based upon active inference. Our objective is to establish a computational and neurophysiological process theory that can be used to disambiguate among the various causes of this important syndrome; namely, a computational neuropsychology of visual neglect. We introduce a Bayes optimal model based upon Markov decision processes that reproduces the visual searches induced by the line cancellation task (used to characterize visual neglect at the bedside). We then consider 3 distinct ways in which the model could be lesioned to reproduce neuropsychological (visual search) deficits. Crucially, these 3 levels of pathology map nicely onto the neuroanatomy of saccadic eye movements and the systems implicated in visual neglect. © The Author 2017. Published by Oxford University Press.

  17. How Choice Ecology Influences Search in Decisions from Experience

    Science.gov (United States)

    Lejarraga, Tomas; Hertwig, Ralph; Gonzalez, Cleotilde

    2012-01-01

    Research into human decision-making has often sidestepped the question of search despite its importance across a wide range of domains such as search for food, mates, allies, visual targets or information. Recently, research on decisions from experience has made progress in finding out how individual characteristics shape search for information.…

  18. Traffic Visualization

    DEFF Research Database (Denmark)

    Picozzi, Matteo; Verdezoto, Nervo; Pouke, Matti

    2013-01-01

    In this paper, we present a space-time visualization to provide city's decision-makers the ability to analyse and uncover important "city events" in an understandable manner for city planning activities. An interactive Web mashup visualization is presented that integrates several visualization...... techniques to give a rapid overview of traffic data. We illustrate our approach as a case study for traffic visualization systems, using datasets from the city of Oulu that can be extended to other city planning activities. We also report the feedback of real users (traffic management employees, traffic police...... officers, city planners) to support our arguments....

  19. Distributed Visualization

    Data.gov (United States)

    National Aeronautics and Space Administration — Distributed Visualization allows anyone, anywhere, to see any simulation, at any time. Development focuses on algorithms, software, data formats, data systems and...

  20. Visualization Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Evaluates and improves the operational effectiveness of existing and emerging electronic warfare systems. By analyzing and visualizing simulation results...

  1. The Visual System

    Medline Plus

    Full Text Available Skip to main content Search Search: Search Search Search the NEI Website search NEI on Social Media | Search A-Z | en español | Text size S M L About NEI NEI Research Accomplishments ...

  2. Visual art and visual perception

    OpenAIRE

    Koenderink, Jan J.

    2015-01-01

    Visual art and visual perception ‘Visual art’ has become a minor cul-de-sac orthogonal to THE ART of the museum directors and billionaire collectors. THE ART is conceptual, instead of visual. Among its cherished items are the tins of artist’s shit (Piero Manzoni, 1961, Merda d’Artista) “worth their weight in gold”. I perceive a metabletic (van den Berg, 1956) parallel to philosophy transforming itself into speculative logic games, and psychology going cognitive by freeing itself from phenomen...

  3. Visual Education

    DEFF Research Database (Denmark)

    Buhl, Mie; Flensborg, Ingelise

    2010-01-01

    The intrinsic breadth of various types of images creates new possibilities and challenges for visual education. The digital media have moved the boundaries between images and other kinds of modalities (e.g. writing, speech and sound) and have augmented the possibilities for integrating the functi......The intrinsic breadth of various types of images creates new possibilities and challenges for visual education. The digital media have moved the boundaries between images and other kinds of modalities (e.g. writing, speech and sound) and have augmented the possibilities for integrating...... to emerge in the interlocutory space of a global visual repertoire and diverse local interpretations. The two perspectives represent challenges for future visual education which require visual competences, not only within the arts but also within the subjects of natural sciences, social sciences, languages...

  4. Visual Inspection for Caries Detection

    DEFF Research Database (Denmark)

    Gimenez, T; Piovesan, C; Braga, M M

    2015-01-01

    We aimed to perform a systematic review including a meta-analysis to evaluate the overall accuracy of visual methods for detecting carious lesions and to identify possible sources of heterogeneity among the studies included. Two reviewers searched PubMed, Embase, Scopus, and other sources through...

  5. Visual cognition.

    Science.gov (United States)

    Cavanagh, Patrick

    2011-07-01

    Visual cognition, high-level vision, mid-level vision and top-down processing all refer to decision-based scene analyses that combine prior knowledge with retinal input to generate representations. The label "visual cognition" is little used at present, but research and experiments on mid- and high-level, inference-based vision have flourished, becoming in the 21st century a significant, if often understated part, of current vision research. How does visual cognition work? What are its moving parts? This paper reviews the origins and architecture of visual cognition and briefly describes some work in the areas of routines, attention, surfaces, objects, and events (motion, causality, and agency). Most vision scientists avoid being too explicit when presenting concepts about visual cognition, having learned that explicit models invite easy criticism. What we see in the literature is ample evidence for visual cognition, but few or only cautious attempts to detail how it might work. This is the great unfinished business of vision research: at some point we will be done with characterizing how the visual system measures the world and we will have to return to the question of how vision constructs models of objects, surfaces, scenes, and events. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Cytoscape ESP: simple search of complex biological networks.

    Science.gov (United States)

    Ashkenazi, Maital; Bader, Gary D; Kuchinsky, Allan; Moshelion, Menachem; States, David J

    2008-06-15

    Cytoscape enhanced search plugin (ESP) enables searching complex biological networks on multiple attribute fields using logical operators and wildcards. Queries use an intuitive syntax and simple search line interface. ESP is implemented as a Cytoscape plugin and complements existing search functions in the Cytoscape network visualization and analysis software, allowing users to easily identify nodes, edges and subgraphs of interest, even for very large networks. Availabiity: http://chianti.ucsd.edu/cyto_web/plugins/ ashkenaz@agri.huji.ac.il.

  7. Organ visualization

    International Nuclear Information System (INIS)

    1975-01-01

    The advantages of selenium-75-labelled cholesterol derivatives for the visualization of the adren in nuclear medicine are outlined. Selenium-75 is a sole gamma emitter; its chemical preparation is described

  8. Visual cognition

    Energy Technology Data Exchange (ETDEWEB)

    Pinker, S.

    1985-01-01

    This book consists of essays covering issues in visual cognition presenting experimental techniques from cognitive psychology, methods of modeling cognitive processes on computers from artificial intelligence, and methods of studying brain organization from neuropsychology. Topics considered include: parts of recognition; visual routines; upward direction; mental rotation, and discrimination of left and right turns in maps; individual differences in mental imagery, computational analysis and the neurological basis of mental imagery: componental analysis.

  9. Visually observing comets

    CERN Document Server

    Seargent, David A J

    2017-01-01

    In these days of computers and CCD cameras, visual comet observers can still contribute scientifically useful data with the help of this handy reference for use in the field. Comets are one of the principal areas for productive pro-amateur collaboration in astronomy, but finding comets requires a different approach than the observing of more predictable targets. Principally directed toward amateur astronomers who prefer visual observing or who are interested in discovering a new comet or visually monitoring the behavior of known comets, it includes all the advice needed to thrive as a comet observer. After presenting a brief overview of the nature of comets and how we came to the modern understanding of comets, this book details the various types of observations that can usefully be carried out at the eyepiece of a telescope. Subjects range from how to search for new comets to visually estimating the brightness of comets and the length and orientation of tails, in addition to what to look for in comet heads a...

  10. Search Term Reports

    Science.gov (United States)

    Learn what search terms brought users to choose your page in their search results, and what terms they entered in the EPA search box after visiting your page. Use this information to improve links and content on the page.

  11. Visualizing water

    Science.gov (United States)

    Baart, F.; van Gils, A.; Hagenaars, G.; Donchyts, G.; Eisemann, E.; van Velzen, J. W.

    2016-12-01

    A compelling visualization is captivating, beautiful and narrative. Here we show how melding the skills of computer graphics, art, statistics, and environmental modeling can be used to generate innovative, attractive and very informative visualizations. We focus on the topic of visualizing forecasts and measurements of water (water level, waves, currents, density, and salinity). For the field of computer graphics and arts, water is an important topic because it occurs in many natural scenes. For environmental modeling and statistics, water is an important topic because the water is essential for transport, a healthy environment, fruitful agriculture, and a safe environment.The different disciplines take different approaches to visualizing water. In computer graphics, one focusses on creating water as realistic looking as possible. The focus on realistic perception (versus the focus on the physical balance pursued by environmental scientists) resulted in fascinating renderings, as seen in recent games and movies. Visualization techniques for statistical results have benefited from the advancement in design and journalism, resulting in enthralling infographics. The field of environmental modeling has absorbed advances in contemporary cartography as seen in the latest interactive data-driven maps. We systematically review the design emerging types of water visualizations. The examples that we analyze range from dynamically animated forecasts, interactive paintings, infographics, modern cartography to web-based photorealistic rendering. By characterizing the intended audience, the design choices, the scales (e.g. time, space), and the explorability we provide a set of guidelines and genres. The unique contributions of the different fields show how the innovations in the current state of the art of water visualization have benefited from inter-disciplinary collaborations.

  12. Visual comparison for information visualization

    KAUST Repository

    Gleicher, M.

    2011-09-07

    Data analysis often involves the comparison of complex objects. With the ever increasing amounts and complexity of data, the demand for systems to help with these comparisons is also growing. Increasingly, information visualization tools support such comparisons explicitly, beyond simply allowing a viewer to examine each object individually. In this paper, we argue that the design of information visualizations of complex objects can, and should, be studied in general, that is independently of what those objects are. As a first step in developing this general understanding of comparison, we propose a general taxonomy of visual designs for comparison that groups designs into three basic categories, which can be combined. To clarify the taxonomy and validate its completeness, we provide a survey of work in information visualization related to comparison. Although we find a great diversity of systems and approaches, we see that all designs are assembled from the building blocks of juxtaposition, superposition and explicit encodings. This initial exploration shows the power of our model, and suggests future challenges in developing a general understanding of comparative visualization and facilitating the development of more comparative visualization tools. © The Author(s) 2011.

  13. Visual cues for data mining

    Science.gov (United States)

    Rogowitz, Bernice E.; Rabenhorst, David A.; Gerth, John A.; Kalin, Edward B.

    1996-04-01

    This paper describes a set of visual techniques, based on principles of human perception and cognition, which can help users analyze and develop intuitions about tabular data. Collections of tabular data are widely available, including, for example, multivariate time series data, customer satisfaction data, stock market performance data, multivariate profiles of companies and individuals, and scientific measurements. In our approach, we show how visual cues can help users perform a number of data mining tasks, including identifying correlations and interaction effects, finding clusters and understanding the semantics of cluster membership, identifying anomalies and outliers, and discovering multivariate relationships among variables. These cues are derived from psychological studies on perceptual organization, visual search, perceptual scaling, and color perception. These visual techniques are presented as a complement to the statistical and algorithmic methods more commonly associated with these tasks, and provide an interactive interface for the human analyst.

  14. Visual cognition

    Energy Technology Data Exchange (ETDEWEB)

    Pinker, S.

    1985-01-01

    This collection of research papers on visual cognition first appeared as a special issue of Cognition: International Journal of Cognitive Science. The study of visual cognition has seen enormous progress in the past decade, bringing important advances in our understanding of shape perception, visual imagery, and mental maps. Many of these discoveries are the result of converging investigations in different areas, such as cognitive and perceptual psychology, artificial intelligence, and neuropsychology. This volume is intended to highlight a sample of work at the cutting edge of this research area for the benefit of students and researchers in a variety of disciplines. The tutorial introduction that begins the volume is designed to help the nonspecialist reader bridge the gap between the contemporary research reported here and earlier textbook introductions or literature reviews.

  15. What Drives Memory-Driven Attentional Capture? The Effects of Memory Type, Display Type, and Search Type

    Science.gov (United States)

    Olivers, Christian N. L.

    2009-01-01

    An important question is whether visual attention (the ability to select relevant visual information) and visual working memory (the ability to retain relevant visual information) share the same content representations. Some past research has indicated that they do: Singleton distractors interfered more strongly with a visual search task when they…

  16. Herp Searches - Spears and Didion Ranches [ds323

    Data.gov (United States)

    California Natural Resource Agency — These data are detections of reptiles in 2005 from visual encounter searches of an area constrained to a 100-m radius circle around each of 15 fixed sample points at...

  17. Information Visualization

    OpenAIRE

    Díaz Baños, Carlos José; Andreasson, Erik

    2012-01-01

    Reasoning graphs are one of many ways to visualize information. It is very hard to understand certain type of information when it is presented in text or in tables with a huge amount of numbers. It is easier to present it graphically. People can have a general idea of the information and if it is necessary to see the details, it is possible to have a way to add more information to the graphical display. A graphical visualization is able to compress the information, which represented in text c...

  18. Visualizing Transformation

    DEFF Research Database (Denmark)

    Pedersen, Pia

    2012-01-01

    Transformation, defined as the step of extracting, arranging and simplifying data into visual form (M. Neurath, 1974), was developed in connection with ISOTYPE (International System Of TYpographic Picture Education) and might well be the most important legacy of Isotype to the field of graphic...... design. Recently transformation has attracted renewed interest because of the book The Transformer written by Robin Kinross and Marie Neurath. My on-going research project, summarized in this paper, identifies and depicts the essential principles of data visualization underlying the process...

  19. Visually scoring hirsutism.

    Science.gov (United States)

    Yildiz, Bulent O; Bolour, Sheila; Woods, Keslie; Moore, April; Azziz, Ricardo

    2010-01-01

    Hirsutism is the presence of excess body or facial terminal (coarse) hair growth in females in a male-like pattern, affects 5-15% of women, and is an important sign of underlying androgen excess. Different methods are available for the assessment of hair growth in women. We conducted a literature search and analyzed the published studies that reported methods for the assessment of hair growth. We review the basic physiology of hair growth, the development of methods for visually quantifying hair growth, the comparison of these methods with objective measurements of hair growth, how hirsutism may be defined using a visual scoring method, the influence of race and ethnicity on hirsutism, and the impact of hirsutism in diagnosing androgen excess and polycystic ovary syndrome. Objective methods for the assessment of hair growth including photographic evaluations and microscopic measurements are available but these techniques have limitations for clinical use, including a significant degree of complexity and a high cost. Alternatively, methods for visually scoring or quantifying the amount of terminal body and facial hair growth have been in use since the early 1920s; these methods are semi-quantitative at best and subject to significant inter-observer variability. The most common visual method of scoring the extent of body and facial terminal hair growth in use today is based on a modification of the method originally described by Ferriman and Gallwey in 1961 (i.e. the mFG method). Overall, the mFG scoring method is a useful visual instrument for assessing excess terminal hair growth, and the presence of hirsutism, in women.

  20. Query-by-Emoji Video Search

    NARCIS (Netherlands)

    Cappallo, S.; Mensink, T.; Snoek, C.G.M.

    2015-01-01

    This technical demo presents Emoji2Video, a query-by-emoji interface for exploring video collections. Ideogram-based video search and representation presents an opportunity for an intuitive, visual interface and concise non-textual summary of video contents, in a form factor that is ideal for small

  1. Content-based Music Search and Recommendation System

    Science.gov (United States)

    Takegawa, Kazuki; Hijikata, Yoshinori; Nishida, Shogo

    Recently, the turn volume of music data on the Internet has increased rapidly. This has increased the user's cost to find music data suiting their preference from such a large data set. We propose a content-based music search and recommendation system. This system has an interface for searching and finding music data and an interface for editing a user profile which is necessary for music recommendation. By exploiting the visualization of the feature space of music and the visualization of the user profile, the user can search music data and edit the user profile. Furthermore, by exploiting the infomation which can be acquired from each visualized object in a mutually complementary manner, we make it easier for the user to search music data and edit the user profile. Concretely, the system gives to the user an information obtained from the user profile when searching music data and an information obtained from the feature space of music when editing the user profile.

  2. submitter Searches at LEP

    CERN Document Server

    Kawagoe, Kiyotomo

    2001-01-01

    Searches for new particles and new physics were extensively performed at LEP. Although no evidence for new particle/physics was discovered, the null results set very stringent limits to theories beyond the standard model. In this paper, searches at LEP and anomalies observed in the searches are presented. Future prospect of searches at the new energy frontier machines is also discussed.

  3. Web Search Engines

    OpenAIRE

    Rajashekar, TB

    1998-01-01

    The World Wide Web is emerging as an all-in-one information source. Tools for searching Web-based information include search engines, subject directories and meta search tools. We take a look at key features of these tools and suggest practical hints for effective Web searching.

  4. Sound Search Engine Concept

    DEFF Research Database (Denmark)

    2006-01-01

    Sound search is provided by the major search engines, however, indexing is text based, not sound based. We will establish a dedicated sound search services with based on sound feature indexing. The current demo shows the concept of the sound search engine. The first engine will be realased June...

  5. How doctors search

    DEFF Research Database (Denmark)

    Lykke, Marianne; Price, Susan; Delcambre, Lois

    2012-01-01

    Professional, workplace searching is different from general searching, because it is typically limited to specific facets and targeted to a single answer. We have developed the semantic component (SC) model, which is a search feature that allows searchers to structure and specify the search...

  6. Visualizing Series

    Science.gov (United States)

    Unal, Hasan

    2008-01-01

    The importance of visualisation and multiple representations in mathematics has been stressed, especially in a context of problem solving. Hanna and Sidoli comment that "Diagrams and other visual representations have long been welcomed as heuristic accompaniments to proof, where they not only facilitate the understanding of theorems and their…

  7. Visual sedimentation.

    Science.gov (United States)

    Huron, Samuel; Vuillemot, Romain; Fekete, Jean-Daniel

    2013-12-01

    We introduce Visual Sedimentation, a novel design metaphor for visualizing data streams directly inspired by the physical process of sedimentation. Visualizing data streams (e. g., Tweets, RSS, Emails) is challenging as incoming data arrive at unpredictable rates and have to remain readable. For data streams, clearly expressing chronological order while avoiding clutter, and keeping aging data visible, are important. The metaphor is drawn from the real-world sedimentation processes: objects fall due to gravity, and aggregate into strata over time. Inspired by this metaphor, data is visually depicted as falling objects using a force model to land on a surface, aggregating into strata over time. In this paper, we discuss how this metaphor addresses the specific challenge of smoothing the transition between incoming and aging data. We describe the metaphor's design space, a toolkit developed to facilitate its implementation, and example applications to a range of case studies. We then explore the generative capabilities of the design space through our toolkit. We finally illustrate creative extensions of the metaphor when applied to real streams of data.

  8. Large Neighborhood Search

    DEFF Research Database (Denmark)

    Pisinger, David; Røpke, Stefan

    2010-01-01

    Heuristics based on large neighborhood search have recently shown outstanding results in solving various transportation and scheduling problems. Large neighborhood search methods explore a complex neighborhood by use of heuristics. Using large neighborhoods makes it possible to find better...... candidate solutions in each iteration and hence traverse a more promising search path. Starting from the large neighborhood search method,we give an overview of very large scale neighborhood search methods and discuss recent variants and extensions like variable depth search and adaptive large neighborhood...... search....

  9. The effect of visual training for patients with visual field defects due to brain damage : a systematic review

    NARCIS (Netherlands)

    Bouwmeester, Lies; Heutink, Joost; Lucas, Cees

    The objective of this review was to evaluate whether systematic visual training leads to ( 1) a restitution of the visual field ( restoration), ( 2) an increase in the visual search field size or an improvement in scanning strategies (compensation) and ( 3) a transfer of training-related

  10. The effect of visual training for patients with visual field defects due to brain damage: a systematic review

    NARCIS (Netherlands)

    Bouwmeester, Lies; Heutink, Joost; Lucas, Cees

    2007-01-01

    The objective of this review was to evaluate whether systematic visual training leads to (1) a restitution of the visual field (restoration), (2) an increase in the visual search field size or an improvement in scanning strategies (compensation) and (3) a transfer of training-related improvements in

  11. Myanmar Language Search Engine

    OpenAIRE

    Pann Yu Mon; Yoshiki Mikami

    2011-01-01

    With the enormous growth of the World Wide Web, search engines play a critical role in retrieving information from the borderless Web. Although many search engines are available for the major languages, but they are not much proficient for the less computerized languages including Myanmar. The main reason is that those search engines are not considering the specific features of those languages. A search engine which capable of searching the Web documents written in those languages is highly n...

  12. Bioinformatics: searching the Net.

    Science.gov (United States)

    Kastin, S; Wexler, J

    1998-04-01

    During the past 30 years, there has been an explosion in the volume of published medical information. As this volume has increased, so has the need for efficient methods for searching the data. MEDLINE, the primary medical database, is currently limited to abstracts of the medical literature. MEDLINE searches use AND/OR/NOT logical searching for keywords that have been assigned to each article and for textwords included in article abstracts. Recently, the complete text of some scientific journals, including figures and tables, has become accessible electronically. Keyword and textword searches can provide an overwhelming number of results. Search engines that use phrase searching, or searches that limit the number of words between two finds, improve the precision of search engines. The development of the Internet as a vehicle for worldwide communication, and the emergence of the World Wide Web (WWW) as a common vehicle for communication have made instantaneous access to much of the entire body of medical information an exciting possibility. There is more than one way to search the WWW for information. At the present time, two broad strategies have emerged for cataloging the WWW: directories and search engines. These allow more efficient searching of the WWW. Directories catalog WWW information by creating categories and subcategories of information and then publishing pointers to information within the category listings. Directories are analogous to yellow pages of the phone book. Search engines make no attempt to categorize information. They automatically scour the WWW looking for words and then automatically create an index of those words. When a specific search engine is used, its index is searched for a particular word. Usually, search engines are nonspecific and produce voluminous results. Use of AND/OR/NOT and "near" and "adjacent" search refinements greatly improve the results of a search. Search engines that limit their scope to specific sites, and

  13. To Search or Not to Search!

    Science.gov (United States)

    Taylor, J. Rodney

    Constitutional guarantees, as provided by the Bill of Rights, are enjoyed by all citizens. This principle applies no less to students with respect to their college or university domicile. Case law on this subject suggests that three questions must be answered to determine the reasonableness of residence searching: (1) by whom the search is…

  14. How do radiologists use the human search engine?

    International Nuclear Information System (INIS)

    Wolfe, Jeremy M.; Evans, Karla K.; Drew, Trafton; Aizenman, Avigael; Josephs, Emilie

    2016-01-01

    Radiologists perform many 'visual search tasks' in which they look for one or more instances of one or more types of target item in a medical image (e.g. cancer screening). To understand and improve how radiologists do such tasks, it must be understood how the human 'search engine' works. This article briefly reviews some of the relevant work into this aspect of medical image perception. Questions include how attention and the eyes are guided in radiologic search? How is global (image-wide) information used in search? How might properties of human vision and human cognition lead to errors in radiologic search? (authors)

  15. HOW DO RADIOLOGISTS USE THE HUMAN SEARCH ENGINE?

    Science.gov (United States)

    Wolfe, Jeremy M.; Evans, Karla K.; Drew, Trafton; Aizenman, Avigael; Josephs, Emilie

    2016-01-01

    Radiologists perform many ‘visual search tasks’ in which they look for one or more instances of one or more types of target item in a medical image (e.g. cancer screening). To understand and improve how radiologists do such tasks, it must be understood how the human ‘search engine’ works. This article briefly reviews some of the relevant work into this aspect of medical image perception. Questions include how attention and the eyes are guided in radiologic search? How is global (image-wide) information used in search? How might properties of human vision and human cognition lead to errors in radiologic search? PMID:26656078

  16. Visual rehabilitation of children with visual impairment

    NARCIS (Netherlands)

    Vervloed, M.P.J.; Janssen, N.M.; Knoors, H.E.T.

    2006-01-01

    Visual rehabilitation, consisting of visual stimulation and visual training, is a common practice in the education of children with visual impairments. Ferrell and Muir have stated that scientific research into the effects of visual stimulation and training is ambiguous and that therefore

  17. Visualizing Progress

    Science.gov (United States)

    2000-01-01

    Reality Capture Technologies, Inc. is a spinoff company from Ames Research Center. Offering e-business solutions for optimizing management, design and production processes, RCT uses visual collaboration environments (VCEs) such as those used to prepare the Mars Pathfinder mission.The product, 4-D Reality Framework, allows multiple users from different locations to manage and share data. The insurance industry is one targeted commercial application for this technology.

  18. The Search Performance Evaluation and Prediction in Exploratory Search

    OpenAIRE

    LIU, FEI

    2016-01-01

    The exploratory search for complex search tasks requires an effective search behavior model to evaluate and predict user search performance. Few studies have investigated the relationship between user search behavior and search performance in exploratory search. This research adopts a mixed approach combining search system development, user search experiment, search query log analysis, and multivariate regression analysis to resolve the knowledge gap. Through this study, it is shown that expl...

  19. Visual Attention at the Tip of the Tongue

    Directory of Open Access Journals (Sweden)

    Michael Barnett-Cowan

    2015-02-01

    Full Text Available The brain shifts attention by selectively modulating sensory information about relevant environmental features. It has been shown that eye, head, trunk and limb position can bias spatial attention. This leads to the interesting question: Does the brain only recruit bodily information that is explicitly related to orienting behaviour to direct attention, or more generally? We tested whether tongue position, which does not explicitly functionally relate to orienting behaviour, biases attention in a visual search task. Thirty-six participants completed three visual search trial blocks of increased difficulty each consisting of three tongue positions for 50 trials. Response times and error rates were used to assess whether tongue position modulates visual attention. Results show that sensorimotor information from the tongue modulates attention in a difficult visual search task: faster responses to visual search targets presented ipsilateral with the tongue; slower responses when contralateral. In line with cognition being generally embodied, the tongue plays a surprising role in directing attention.

  20. Manneristic behaviors of visually impaired children.

    Science.gov (United States)

    Molloy, Alysha; Rowe, Fiona J

    2011-09-01

    To review the literature on visual impairment in children in order to determine which manneristic behaviors are associated with visual impairment, and to establish why these behaviors occur and whether severity of visual impairment influences these behaviors. A literature search utilizing PubMed, OVID, Google Scholar, and Web of Knowledge databases was performed. The University of Liverpool ( www.liv.ac.uk/orthoptics/research ) and local library facilities were also searched. The main manneristic or stereotypic behaviors associated with visual impairment are eye-manipulatory behaviors, such as eye poking and rocking. The degree of visual impairment influences the type of behavior exhibited by visually impaired children. Totally blind children are more likely to adopt body and head movements whereas sight-impaired children tend to adopt eye-manipulatory behaviors and rocking. The mannerisms exhibited most frequently are those that provide a specific stimulation to the child. Theories to explain these behaviors include behavioral, developmental, functional, and neurobiological approaches. Although the precise etiology of these behaviors is unknown, it is recognized that each of the theories is useful in providing some explanation of why certain behaviors may occur. The age at which the frequency of these behaviors decreases is associated with the child's increasing development, thus those visually impaired children with additional disabilities, whose development is impaired, are at an increased risk of developing and maintaining these behaviors. Certain manneristic behaviors of the visually impaired child may also help indicate the cause of visual impairment. There is a wide range of manneristic behaviors exhibited by visually impaired children. Some of these behaviors appear to be particularly associated with certain causes of visual impairment or severity of visual impairment, thus they may supply the practitioner with useful information. Further research into the

  1. Cognitive Foundations for Visual Analytics

    Energy Technology Data Exchange (ETDEWEB)

    Greitzer, Frank L.; Noonan, Christine F.; Franklin, Lyndsey

    2011-02-25

    In this report, we provide an overview of scientific/technical literature on information visualization and VA. Topics discussed include an update and overview of the extensive literature search conducted for this study, the nature and purpose of the field, major research thrusts, and scientific foundations. We review methodologies for evaluating and measuring the impact of VA technologies as well as taxonomies that have been proposed for various purposes to support the VA community. A cognitive science perspective underlies each of these discussions.

  2. Controlling the spotlight of attention: visual span size and flexibility in schizophrenia.

    Science.gov (United States)

    Elahipanah, Ava; Christensen, Bruce K; Reingold, Eyal M

    2011-10-01

    The current study investigated the size and flexible control of visual span among patients with schizophrenia during visual search performance. Visual span is the region of the visual field from which one extracts information during a single eye fixation, and a larger visual span size is linked to more efficient search performance. Therefore, a reduced visual span may explain patients' impaired performance on search tasks. The gaze-contingent moving window paradigm was used to estimate the visual span size of patients and healthy participants while they performed two different search tasks. In addition, changes in visual span size were measured as a function of two manipulations of task difficulty: target-distractor similarity and stimulus familiarity. Patients with schizophrenia searched more slowly across both tasks and conditions. Patients also demonstrated smaller visual span sizes on the easier search condition in each task. Moreover, healthy controls' visual span size increased as target discriminability or distractor familiarity increased. This modulation of visual span size, however, was reduced or not observed among patients. The implications of the present findings, with regard to previously reported visual search deficits, and other functional and structural abnormalities associated with schizophrenia, are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Visual Attention and Saccadic Oculomotor Control in Parkinson's Disease.

    Science.gov (United States)

    Buhmann, Carsten; Kraft, Stefanie; Hinkelmann, Kim; Krause, Sven; Gerloff, Christian; Zangemeister, Wolfgang H

    2015-01-01

    In patients with Parkinson's disease (PD) we aimed at differentiating the relation between selective visual attention, deficits of programming and dynamics of saccadic eye movements while searching for a target and hand-reaction time as well as hand-movement time. Visual attention is crucial for concentrating selectively on one aspect of the visual field while ignoring other aspects. Eye movements are anatomically and functionally related to mechanisms of visual attention. Saccadic dysfunction might confound selective visual attention in PD. We studied visual selective attention in 22 medicated PD patients (clinical ON status, mild to moderate disease severity) and 22 age matched controls. We looked for possible interferences through oculomotor deficits. Two tasks were compared: free viewing of photographs and time optimal visual search of a hidden target. Visual search times (VST), task related dynamics of saccades, and hand-reaction and hand-movement times were analyzed. In the free viewing task mild to moderately affected PD patients did not differ statistically from healthy subjects with respect to saccade dynamics. However, patients differed significantly from healthy subjects in the time optimal visual search task with 25% lower rates of successful searches. Hand movement reaction time did not differ in both groups, whereas hand movement execution time was significantly prolonged in PD patients. Saccadic oculomotor control and hand movement reaction times were intact, whereas in our less severely affected treated PD patients, visual selective attention was not. The highly reduced successful search rate might be related to disturbed programming and delayed execution of saccades during time optimal visual search due to decreased execution of serial-order sequential generation of saccades. © 2015 S. Karger AG, Basel.

  4. Searching for Orphan radiation sources

    International Nuclear Information System (INIS)

    Bystrov, Evgenij; Antonau, Uladzimir; Gurinovich, Uladzimir; Kazhamiakin, Valery; Petrov, Vitaly; Shulhovich, Heorhi; Tischenko, Siarhei

    2008-01-01

    Full text: The problem of orphan sources cannot be left unaddressed due high probability of accidental exposure and use of sources for terrorism. Search of objects of this kind is complex particularly when search territory is large. This requires devices capable of detecting sources, identifying their radionuclide composition, and correlating scan results to geographical coordinates and displaying results on a map. Spectral radiation scanner AT6101C can fulfill the objective of search for gamma and neutron radiation sources, radionuclide composition identification, correlation results to geographical coordinates and displaying results on a map. The scanner consists of gamma radiation scintillation detection unit based on NaI(Tl) crystal, neutron detection unit based on two He 3 counters, GPS receiver and portable ruggedized computer. Built-in and application software automates entire scan process, saving all results to memory for further analysis with visual representation of results as spectral information diagrams, count rate profile and gamma radiation dose rates on a geographical map. The scanner informs operator with voice messages on detection of radiation sources, identification result and other events. Scanner detection units and accessories are packed in a backpack. Weighing 7 kg, the scanner is human portable and can be used for scan inside cars. The scanner can also be used for radiation mapping and inspections. (author)

  5. Integrated vs. Federated Search

    DEFF Research Database (Denmark)

    Løvschall, Kasper

    2009-01-01

    Oplæg om forskelle og ligheder mellem integrated og federated search i bibliotekskontekst. Holdt ved temadag om "Integrated Search - samsøgning i alle kilder" på Danmarks Biblioteksskole den 22. januar 2009.......Oplæg om forskelle og ligheder mellem integrated og federated search i bibliotekskontekst. Holdt ved temadag om "Integrated Search - samsøgning i alle kilder" på Danmarks Biblioteksskole den 22. januar 2009....

  6. The Information Search

    Science.gov (United States)

    Doraiswamy, Uma

    2011-01-01

    This paper in the form of story discusses a college student's information search process. In this story we see Kuhlthau's information search process: initiation, selection, exploration, formulation, collection, and presentation. Katie is a student who goes in search of information for her class research paper. Katie's class readings, her interest…

  7. The forensic validity of visual analytics

    Science.gov (United States)

    Erbacher, Robert F.

    2008-01-01

    The wider use of visualization and visual analytics in wide ranging fields has led to the need for visual analytics capabilities to be legally admissible, especially when applied to digital forensics. This brings the need to consider legal implications when performing visual analytics, an issue not traditionally examined in visualization and visual analytics techniques and research. While digital data is generally admissible under the Federal Rules of Evidence [10][21], a comprehensive validation of the digital evidence is considered prudent. A comprehensive validation requires validation of the digital data under rules for authentication, hearsay, best evidence rule, and privilege. Additional issues with digital data arise when exploring digital data related to admissibility and the validity of what information was examined, to what extent, and whether the analysis process was sufficiently covered by a search warrant. For instance, a search warrant generally covers very narrow requirements as to what law enforcement is allowed to examine and acquire during an investigation. When searching a hard drive for child pornography, how admissible is evidence of an unrelated crime, i.e. drug dealing. This is further complicated by the concept of "in plain view". When performing an analysis of a hard drive what would be considered "in plain view" when analyzing a hard drive. The purpose of this paper is to discuss the issues of digital forensics and the related issues as they apply to visual analytics and identify how visual analytics techniques fit into the digital forensics analysis process, how visual analytics techniques can improve the legal admissibility of digital data, and identify what research is needed to further improve this process. The goal of this paper is to open up consideration of legal ramifications among the visualization community; the author is not a lawyer and the discussions are not meant to be inclusive of all differences in laws between states and

  8. Understanding Consumers' In-store Visual Perception

    DEFF Research Database (Denmark)

    Clement, Jesper; Kristensen, Tore; Grønhaug, Kjell

    2013-01-01

    It is widely accepted that the human brain has limited capacity for perceptual stimuli and consumers'' visual attention, when searching for a particular product or brand in a grocery store, should then be limited by the boundaries of their own perceptual capacity. In this exploratory study, we...... examine the relationship between abundant in-store stimuli and limited human perceptual capacity. Specifically, we test the influence of package design features on visual attention. Data was collected through two eye-tracking experiments, one in a grocery store using wireless eye-tracking equipment......, and another in a lab setting. Findings show that consumers have fragmented visual attention during grocery shopping, and that their visual attention is simultaneously influenced and disrupted by the shelf display. Physical design features such as shape and contrast dominate the initial phase of searching...

  9. Satisfaction in motion: Subsequent search misses are more likely in moving search displays.

    Science.gov (United States)

    Stothart, Cary; Clement, Andrew; Brockmole, James R

    2018-02-01

    People often conduct visual searches in which multiple targets are possible (e.g., medical X-rays can contain multiple abnormalities). In this type of search, observers are more likely to miss a second target after having found a first one (a subsequent search miss). Recent evidence has suggested that this effect may be due to a depletion of cognitive resources from tracking the identities and locations of found targets. Given that tracking moving objects is resource-demanding, would finding a moving target further increase the chances of missing a subsequent one? To address this question, we had participants search for one or more targets hidden among distractors. Subsequent search misses were more likely when the targets and distractors moved throughout the display than when they remained stationary. However, when the found targets were highlighted in a unique color, subsequent search misses were no more likely in moving displays. Together, these results suggest that the effect of movement is likely due to the increased cognitive demands of tracking moving targets. Overall, our findings reveal that activities that involve searching for moving targets (e.g., driving) are more susceptible to subsequent search misses than are those that involve searching for stationary targets (e.g., baggage screening).

  10. Keyword Search in Databases

    CERN Document Server

    Yu, Jeffrey Xu; Chang, Lijun

    2009-01-01

    It has become highly desirable to provide users with flexible ways to query/search information over databases as simple as keyword search like Google search. This book surveys the recent developments on keyword search over databases, and focuses on finding structural information among objects in a database using a set of keywords. Such structural information to be returned can be either trees or subgraphs representing how the objects, that contain the required keywords, are interconnected in a relational database or in an XML database. The structural keyword search is completely different from

  11. Visualization of ocean forecast in BYTHOS

    Science.gov (United States)

    Zhuk, E.; Zodiatis, G.; Nikolaidis, A.; Stylianou, S.; Karaolia, A.

    2016-08-01

    The Cyprus Oceanography Center has been constantly searching for new ideas for developing and implementing innovative methods and new developments concerning the use of Information Systems in Oceanography, to suit both the Center's monitoring and forecasting products. Within the frame of this scope two major online managing and visualizing data systems have been developed and utilized, those of CYCOFOS and BYTHOS. The Cyprus Coastal Ocean Forecasting and Observing System - CYCOFOS provides a variety of operational predictions such as ultra high, high and medium resolution ocean forecasts in the Levantine Basin, offshore and coastal sea state forecasts in the Mediterranean and Black Sea, tide forecasting in the Mediterranean, ocean remote sensing in the Eastern Mediterranean and coastal and offshore monitoring. As a rich internet application, BYTHOS enables scientists to search, visualize and download oceanographic data online and in real time. The recent improving of BYTHOS system is the extension with access and visualization of CYCOFOS data and overlay forecast fields and observing data. The CYCOFOS data are stored at OPENDAP Server in netCDF format. To search, process and visualize it the php and python scripts were developed. Data visualization is achieved through Mapserver. The BYTHOS forecast access interface allows to search necessary forecasting field by recognizing type, parameter, region, level and time. Also it provides opportunity to overlay different forecast and observing data that can be used for complex analyze of sea basin aspects.

  12. How information visualization novices construct visualizations.

    Science.gov (United States)

    Grammel, Lars; Tory, Melanie; Storey, Margaret-Anne

    2010-01-01

    It remains challenging for information visualization novices to rapidly construct visualizations during exploratory data analysis. We conducted an exploratory laboratory study in which information visualization novices explored fictitious sales data by communicating visualization specifications to a human mediator, who rapidly constructed the visualizations using commercial visualization software. We found that three activities were central to the iterative visualization construction process: data attribute selection, visual template selection, and visual mapping specification. The major barriers faced by the participants were translating questions into data attributes, designing visual mappings, and interpreting the visualizations. Partial specification was common, and the participants used simple heuristics and preferred visualizations they were already familiar with, such as bar, line and pie charts. We derived abstract models from our observations that describe barriers in the data exploration process and uncovered how information visualization novices think about visualization specifications. Our findings support the need for tools that suggest potential visualizations and support iterative refinement, that provide explanations and help with learning, and that are tightly integrated into tool support for the overall visual analytics process.

  13. Neural field model of memory-guided search.

    Science.gov (United States)

    Kilpatrick, Zachary P; Poll, Daniel B

    2017-12-01

    Many organisms can remember locations they have previously visited during a search. Visual search experiments have shown exploration is guided away from these locations, reducing redundancies in the search path before finding a hidden target. We develop and analyze a two-layer neural field model that encodes positional information during a search task. A position-encoding layer sustains a bump attractor corresponding to the searching agent's current location, and search is modeled by velocity input that propagates the bump. A memory layer sustains persistent activity bounded by a wave front, whose edges expand in response to excitatory input from the position layer. Search can then be biased in response to remembered locations, influencing velocity inputs to the position layer. Asymptotic techniques are used to reduce the dynamics of our model to a low-dimensional system of equations that track the bump position and front boundary. Performance is compared for different target-finding tasks.

  14. Neural field model of memory-guided search

    Science.gov (United States)

    Kilpatrick, Zachary P.; Poll, Daniel B.

    2017-12-01

    Many organisms can remember locations they have previously visited during a search. Visual search experiments have shown exploration is guided away from these locations, reducing redundancies in the search path before finding a hidden target. We develop and analyze a two-layer neural field model that encodes positional information during a search task. A position-encoding layer sustains a bump attractor corresponding to the searching agent's current location, and search is modeled by velocity input that propagates the bump. A memory layer sustains persistent activity bounded by a wave front, whose edges expand in response to excitatory input from the position layer. Search can then be biased in response to remembered locations, influencing velocity inputs to the position layer. Asymptotic techniques are used to reduce the dynamics of our model to a low-dimensional system of equations that track the bump position and front boundary. Performance is compared for different target-finding tasks.

  15. Distinct perceptual rhythms for feature and conjunction searches

    Science.gov (United States)

    Dugué, Laura; Xue, Alice M.; Carrasco, Marisa

    2017-01-01

    Feature and conjunction searches are widely used to study attentional deployment. However, the spatiotemporal behavior of attention integration in these tasks remains under debate. Are multiple search stimuli processed in parallel or sequentially? Does sampling of visual information and attentional deployment differ between these two types of search? If so, how? We used an innovative methodology to estimate the distribution of attention on a single-trial basis for feature and conjunction searches. Observers performed feature- and conjunction-search tasks. They had to detect and discriminate a tilted low-spatial-frequency grating among three low-spatial-frequency vertical gratings (feature search) or low-spatial-frequency vertical gratings and high-spatial-frequency tilted gratings (conjunction search). After a variable delay, two probes were flashed at random locations. Performance in reporting the probes was used to infer attentional deployment to those locations. By solving a second-degree equation, we determined the probability of probe report at the most (P1) and least (P2) attended locations on a given trial. Were P1 and P2 equal, we would conclude that attention had been uniformly distributed across all four locations. Otherwise, we would conclude that visual information sampling and attentional deployment had been nonuniformly distributed. Our results show that processing was nonuniformly distributed across the four locations in both searches, and was modulated periodically over time at ∼5 Hz for the conjunction search and ∼12 Hz for the feature search. We argue that the former corresponds to the periodicity of attentional deployment during the search, whereas the latter corresponds to ongoing sampling of visual information. Because different locations were not simultaneously processed, this study rules out a strict parallel model for both search types. PMID:28362897

  16. Visualization rhetoric: framing effects in narrative visualization.

    Science.gov (United States)

    Hullman, Jessica; Diakopoulos, Nicholas

    2011-12-01

    Narrative visualizations combine conventions of communicative and exploratory information visualization to convey an intended story. We demonstrate visualization rhetoric as an analytical framework for understanding how design techniques that prioritize particular interpretations in visualizations that "tell a story" can significantly affect end-user interpretation. We draw a parallel between narrative visualization interpretation and evidence from framing studies in political messaging, decision-making, and literary studies. Devices for understanding the rhetorical nature of narrative information visualizations are presented, informed by the rigorous application of concepts from critical theory, semiotics, journalism, and political theory. We draw attention to how design tactics represent additions or omissions of information at various levels-the data, visual representation, textual annotations, and interactivity-and how visualizations denote and connote phenomena with reference to unstated viewing conventions and codes. Classes of rhetorical techniques identified via a systematic analysis of recent narrative visualizations are presented, and characterized according to their rhetorical contribution to the visualization. We describe how designers and researchers can benefit from the potentially positive aspects of visualization rhetoric in designing engaging, layered narrative visualizations and how our framework can shed light on how a visualization design prioritizes specific interpretations. We identify areas where future inquiry into visualization rhetoric can improve understanding of visualization interpretation. © 2011 IEEE

  17. IMPROVING PERSONALIZED WEB SEARCH USING BOOKSHELF DATA STRUCTURE

    Directory of Open Access Journals (Sweden)

    S.K. Jayanthi

    2012-10-01

    Full Text Available Search engines are playing a vital role in retrieving relevant information for the web user. In this research work a user profile based web search is proposed. So the web user from different domain may receive different set of results. The main challenging work is to provide relevant results at the right level of reading difficulty. Estimating user expertise and re-ranking the results are the main aspects of this paper. The retrieved results are arranged in Bookshelf Data Structure for easy access. Better presentation of search results hence increases the usability of web search engines significantly in visual mode.

  18. Adaptive Large Neighbourhood Search

    DEFF Research Database (Denmark)

    Røpke, Stefan

    Large neighborhood search is a metaheuristic that has gained popularity in recent years. The heuristic repeatedly moves from solution to solution by first partially destroying the solution and then repairing it. The best solution observed during this search is presented as the final solution....... This tutorial introduces the large neighborhood search metaheuristic and the variant adaptive large neighborhood search that dynamically tunes parameters of the heuristic while it is running. Both heuristics belong to a broader class of heuristics that are searching a solution space using very large...... neighborhoods. The tutorial also present applications of the adaptive large neighborhood search, mostly related to vehicle routing problems for which the heuristic has been extremely successful. We discuss how the heuristic can be parallelized and thereby take advantage of modern desktop computers...

  19. Search on Rugged Landscapes

    DEFF Research Database (Denmark)

    Billinger, Stephan; Stieglitz, Nils; Schumacher, Terry

    2014-01-01

    This paper presents findings from a laboratory experiment on human decision-making in a complex combinatorial task. We find strong evidence for a behavioral model of adaptive search. Success narrows down search to the neighborhood of the status quo, while failure promotes gradually more explorative...... search. Task complexity does not have a direct effect on behavior, but systematically affects the feedback conditions that guide success-induced exploitation and failure-induced exploration. The analysis also shows that human participants were prone to over-exploration, since they broke off the search...... for local improvements too early. We derive stylized decision rules that generate the search behavior observed in the experiment and discuss the implications of our findings for individual decision-making and organizational search....

  20. University Students' Online Information Searching Strategies in Different Search Contexts

    Science.gov (United States)

    Tsai, Meng-Jung; Liang, Jyh-Chong; Hou, Huei-Tse; Tsai, Chin-Chung

    2012-01-01

    This study investigates the role of search context played in university students' online information searching strategies. A total of 304 university students in Taiwan were surveyed with questionnaires in which two search contexts were defined as searching for learning, and searching for daily life information. Students' online search strategies…

  1. [Advanced online search techniques and dedicated search engines for physicians].

    Science.gov (United States)

    Nahum, Yoav

    2008-02-01

    In recent years search engines have become an essential tool in the work of physicians. This article will review advanced search techniques from the world of information specialists, as well as some advanced search engine operators that may help physicians improve their online search capabilities, and maximize the yield of their searches. This article also reviews popular dedicated scientific and biomedical literature search engines.

  2. Mobile Search and Advertising

    OpenAIRE

    Lovitskii, Vladimir; McCaffery, Colin; Thrasher, Michael; Traynor, David; Wright, Peter

    2009-01-01

    Mobile advertising is a rapidly growing sector providing brands and marketing agencies the opportunity to connect with consumers beyond traditional and digital media and instead communicate directly on their mobile phones. Mobile advertising will be intrinsically linked with mobile search, which has transported from the internet to the mobile and is identified as an area of potential growth. The result of mobile searching show that as a general rule such search result exceed 1...

  3. Mastering ElasticSearch

    CERN Document Server

    Kuc, Rafal

    2013-01-01

    A practical tutorial that covers the difficult design, implementation, and management of search solutions.Mastering ElasticSearch is aimed at to intermediate users who want to extend their knowledge about ElasticSearch. The topics that are described in the book are detailed, but we assume that you already know the basics, like the query DSL or data indexing. Advanced users will also find this book useful, as the examples are getting deep into the internals where it is needed.

  4. ElasticSearch cookbook

    CERN Document Server

    Paro, Alberto

    2013-01-01

    Written in an engaging, easy-to-follow style, the recipes will help you to extend the capabilities of ElasticSearch to manage your data effectively.If you are a developer who implements ElasticSearch in your web applications, manage data, or have decided to start using ElasticSearch, this book is ideal for you. This book assumes that you've got working knowledge of JSON and Java

  5. Search Analytics: Automated Learning, Analysis, and Search with Open Source

    Science.gov (United States)

    Hundman, K.; Mattmann, C. A.; Hyon, J.; Ramirez, P.

    2016-12-01

    The sheer volume of unstructured scientific data makes comprehensive human analysis impossible, resulting in missed opportunities to identify relationships, trends, gaps, and outliers. As the open source community continues to grow, tools like Apache Tika, Apache Solr, Stanford's DeepDive, and Data-Driven Documents (D3) can help address this challenge. With a focus on journal publications and conference abstracts often in the form of PDF and Microsoft Office documents, we've initiated an exploratory NASA Advanced Concepts project aiming to use the aforementioned open source text analytics tools to build a data-driven justification for the HyspIRI Decadal Survey mission. We call this capability Search Analytics, and it fuses and augments these open source tools to enable the automatic discovery and extraction of salient information. In the case of HyspIRI, a hyperspectral infrared imager mission, key findings resulted from the extractions and visualizations of relationships from thousands of unstructured scientific documents. The relationships include links between satellites (e.g. Landsat 8), domain-specific measurements (e.g. spectral coverage) and subjects (e.g. invasive species). Using the above open source tools, Search Analytics mined and characterized a corpus of information that would be infeasible for a human to process. More broadly, Search Analytics offers insights into various scientific and commercial applications enabled through missions and instrumentation with specific technical capabilities. For example, the following phrases were extracted in close proximity within a publication: "In this study, hyperspectral images…with high spatial resolution (1 m) were analyzed to detect cutleaf teasel in two areas. …Classification of cutleaf teasel reached a users accuracy of 82 to 84%." Without reading a single paper we can use Search Analytics to automatically identify that a 1 m spatial resolution provides a cutleaf teasel detection users accuracy of 82

  6. Use of Cognitive and Metacognitive Strategies in Online Search: An Eye-Tracking Study

    Science.gov (United States)

    Zhou, Mingming; Ren, Jing

    2016-01-01

    This study used eye-tracking technology to track students' eye movements while searching information on the web. The research question guiding this study was "Do students with different search performance levels have different visual attention distributions while searching information online? If yes, what are the patterns for high and low…

  7. Google Power Search

    CERN Document Server

    Spencer, Stephan

    2011-01-01

    Behind Google's deceptively simple interface is immense power for both market and competitive research-if you know how to use it well. Sure, basic searches are easy, but complex searches require specialized skills. This concise book takes you through the full range of Google's powerful search-refinement features, so you can quickly find the specific information you need. Learn techniques ranging from simple Boolean logic to URL parameters and other advanced tools, and see how they're applied to real-world market research examples. Incorporate advanced search operators such as filetype:, intit

  8. Supersymmetry searches at CMS

    Directory of Open Access Journals (Sweden)

    Bargassa Pedrame

    2014-04-01

    Full Text Available The accumulation of 19 fb−1 of data at 8 TeV has been a unique window for Supersymmetry searches at the LHC, allowing the CMS collaboration to search for specific supersymmetric particles. This article covers the search for supersymmetric particles in a variety of production-and decay-modes as well as channels. It focuses on the search for the lightest scalar top (stop in the single lepton channel, stop which might be the only observable in the case where Supersymmetry is realized in nature, and which can play a unique role in “naturalness”

  9. Exotic Higgs searches

    CERN Document Server

    Pelliccioni, Mario

    2016-01-01

    Exotic Higgs searches cover a wide range of signatures, thus leading to indications to new physics beyond Standard Model. We report a review on exotic Higgs searches for lepton flavour violating Higgs decays, for "mono-Higgs" searches, for Higgs decays to invisible and for high mass Higgs searches. Both ATLAS and CMS results will be shown, for Run-1 data statistics collected at the energy of $\\sqrt s$ = 7,8 TeV and for the first data collected during Run-2 phase at the energy of $\\sqrt s$ = 13 TeV.

  10. Unstoppable, sbottomless sfermion searches

    Science.gov (United States)

    Trigger, Isabel

    Results are presented from searches by the LEP collaborations for scalar partners of leptons and light quarks in the context of the Minimal Supersymmetric Standard Model (MSSM). Examples shown are searches by OPAL for events with two leptons and significant missing transverse momentum and events with anomalous dE/dx, L3 searches for mass-degenerate squarks and for single electrons, and a DELPHI search for staus of mass less than MZ0/2. No evidence is observed for any signal indicating physics beyond the Standard Model (SM). Limits are shown in the context of a constrained MSSM (CMSSM).

  11. Unstoppable, bottomless sfermion searches

    Energy Technology Data Exchange (ETDEWEB)

    Trigger, Isabel [CERN (Switzerland)

    2004-07-01

    Results are presented from searches by the LEP collaborations for scalar partners of leptons and light quarks in the context of the Minimal Supersymmetric Standard Model (MSSM). Examples shown are searches by OPAL for events with two leptons and significant missing transverse momentum and events with anomalous dE/dx, L3 searches for mass-degenerate squarks and for single electrons, and a DELPHI search for staus of mass less than M{sub Z{sup 0/2}}. No evidence is observed for any signal indicating physics beyond the Standard Model (SM). Limits are shown in the context of a constrained MSSM (CMSSM). (orig.)

  12. Unstoppable, bottomless sfermion searches

    International Nuclear Information System (INIS)

    Trigger, Isabel

    2004-01-01

    Results are presented from searches by the LEP collaborations for scalar partners of leptons and light quarks in the context of the Minimal Supersymmetric Standard Model (MSSM). Examples shown are searches by OPAL for events with two leptons and significant missing transverse momentum and events with anomalous dE/dx, L3 searches for mass-degenerate squarks and for single electrons, and a DELPHI search for staus of mass less than M Z 0 /2. No evidence is observed for any signal indicating physics beyond the Standard Model (SM). Limits are shown in the context of a constrained MSSM (CMSSM). (orig.)

  13. Detailed illustration of the visual field representation along the visual pathway to the primary visual cortex: a graphical summary.

    Science.gov (United States)

    Wärntges, Simone; Michelson, Georg

    2014-01-01

    In the literature, different graphic illustrations are available, which depict different parts of the visual pathway in relation to visual field sectors, to retinal sectors, the layers of the lateral geniculate nucleus (LGN), or sections of the primary visual cortex (V1). However, a complete overview is missing, which may be useful for a more precise differentiation of predominantly ophthalmological from intracerebral diseases. It may also be of interest to investigate additional intracerebral reasons that are involved in impaired vision of largely unknown pathophysiology. This work combines the scientific knowledge of partial graphics in one detailed illustration that allows exact follow-up of the neuronal connections from individual visual field sectors to the V1 areas. A selective search for peer-reviewed graphics of the visual pathway was performed in PubMed and Google Pictures. Sixteen different visual field sectors and their 16 corresponding retinal sectors were set in relation to 64 LGN sections and 20 areas of V1. Segmented cross-sectional areas of the optic nerve supplemented the graphical representation of the fiber orientation in relation to the visual field. The detailed illustration of the visual field projection along the visual pathway structures may facilitate a more precise calculation of correlations between morphological and functional measurements of ophthalmological and neuroradiological examinations. © 2013 S. Karger AG, Basel.

  14. Musician Map: visualizing music collaborations over time

    Science.gov (United States)

    Yim, Ji-Dong; Shaw, Chris D.; Bartram, Lyn

    2009-01-01

    In this paper we introduce Musician Map, a web-based interactive tool for visualizing relationships among popular musicians who have released recordings since 1950. Musician Map accepts search terms from the user, and in turn uses these terms to retrieve data from MusicBrainz.org and AudioScrobbler.net, and visualizes the results. Musician Map visualizes relationships of various kinds between music groups and individual musicians, such as band membership, musical collaborations, and linkage to other artists that are generally regarded as being similar in musical style. These relationships are plotted between artists using a new timeline-based visualization where a node in a traditional node-link diagram has been transformed into a Timeline-Node, which allows the visualization of an evolving entity over time, such as the membership in a band. This allows the user to pursue social trend queries such as "Do Hip-Hop artists collaborate differently than Rock artists".

  15. Nonsequential search equilibrium with search cost heterogeneity

    NARCIS (Netherlands)

    Moraga-Gonzalez, Jose Luis; Sandor, Zsolt; Wildenbeest, Matthijs R.

    We generalize the model of Burdett and Judd (1983) to the case where an arbitrary finite number of firms sells a homogeneous good to buyers who have heterogeneous search costs. We show that a price dispersed symmetric Nash equilibrium always exists. Numerical results show that the behavior of prices

  16. Citation Searching: Search Smarter & Find More

    Science.gov (United States)

    Hammond, Chelsea C.; Brown, Stephanie Willen

    2008-01-01

    The staff at University of Connecticut are participating in Elsevier's Student Ambassador Program (SAmP) in which graduate students train their peers on "citation searching" research using Scopus and Web of Science, two tremendous citation databases. They are in the fourth semester of these training programs, and they are wildly successful: They…

  17. The Allocation of Visual Attention in Multimedia Search Interfaces

    Science.gov (United States)

    Hughes, Edith Allen

    2017-01-01

    Multimedia analysts are challenged by the massive numbers of unconstrained video clips generated daily. Such clips can include any possible scene and events, and generally have limited quality control. Analysts who must work with such data are overwhelmed by its volume and lack of computational tools to probe it effectively. Even with advances…

  18. Case law retrieval by concept search and visualization

    NARCIS (Netherlands)

    Uijttenbroek, Elisabeth M.; Klein, Michel C.A.; Lodder, Arno R.; Van Harmelen, Frank

    2007-01-01

    The BEST-project (BATNA Establishment using Semantic web Technology, http://best-project.nl) strives to provide disputing parties with information about their legal position in a liability case. Our assumption is that through intelligent disclosure of Dutch Tort Law cases, laymen can estimate their

  19. Advancing the Relevance Criteria for Video Search and Visual Summarization

    NARCIS (Netherlands)

    Rudinac, S.

    2013-01-01

    To facilitate finding of relevant information in ever-growing multimedia collections, a number of multimedia information retrieval solutions have been proposed over the past years. The essential element of any such solution is the relevance criterion deployed to select or rank the items from a

  20. Visualizing Entropy

    Science.gov (United States)

    Lechner, Joseph H.

    1999-10-01

    This report describes two classroom activities that help students visualize the abstract concept of entropy and apply the second law of thermodynamics to real situations. (i) A sealed "rainbow tube" contains six smaller vessels, each filled with a different brightly colored solution (low entropy). When the tube is inverted, the solutions mix together and react to form an amorphous precipitate (high entropy). The change from low entropy to high entropy is irreversible as long as the tube remains sealed. (ii) When U.S. currency is withdrawn from circulation, intact bills (low entropy) are shredded into small fragments (high entropy). Shredding is quick and easy; the reverse process is clearly nonspontaneous. It is theoretically possible, but it is time-consuming and energy-intensive, to reassemble one bill from a pile that contains fragments of hundreds of bills. We calculate the probability P of drawing pieces of only one specific bill from a mixture containing one pound of bills, each shredded into n fragments. This result can be related to Boltzmann's entropy formula S?=klnW.

  1. Visual Literacy in Instructional Design Programs

    Science.gov (United States)

    Ervine, Michelle D.

    2016-01-01

    In this technologically advanced environment, users have become highly visual, with television, videos, web sites and images dominating the learning environment. These new forms of searching and learning are changing the perspective of what it means to be literate. Literacy can no longer solely rely on text-based materials, but should also…

  2. Visual selective attention in amnestic mild cognitive impairment.

    Science.gov (United States)

    McLaughlin, Paula M; Anderson, Nicole D; Rich, Jill B; Chertkow, Howard; Murtha, Susan J E

    2014-11-01

    Subtle deficits in visual selective attention have been found in amnestic mild cognitive impairment (aMCI). However, few studies have explored performance on visual search paradigms or the Simon task, which are known to be sensitive to disease severity in Alzheimer's patients. Furthermore, there is limited research investigating how deficiencies can be ameliorated with exogenous support (auditory cues). Sixteen individuals with aMCI and 14 control participants completed 3 experimental tasks that varied in demand and cue availability: visual search-alerting, visual search-orienting, and Simon task. Visual selective attention was influenced by aMCI, auditory cues, and task characteristics. Visual search abilities were relatively consistent across groups. The aMCI participants were impaired on the Simon task when working memory was required, but conflict resolution was similar to controls. Spatially informative orienting cues improved response times, whereas spatially neutral alerting cues did not influence performance. Finally, spatially informative auditory cues benefited the aMCI group more than controls in the visual search task, specifically at the largest array size where orienting demands were greatest. These findings suggest that individuals with aMCI have working memory deficits and subtle deficiencies in orienting attention and rely on exogenous information to guide attention. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Agrosearch: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  4. Africa Development: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  5. African Anthropologist: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  6. Biokemistri: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  7. Acta Structilia: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  8. Measuring Online Search Expertise

    Science.gov (United States)

    Bailey, Earl

    2017-01-01

    Search expertise has long been studied and used extensively in information seeking behavior research, both as a fundamental concept and as a method of comparing groups of users. Unfortunately, while search expertise has been studied for some time, the conceptualization of it has lagged behind its use in categorizing users. This has led to users…

  9. Ergonomics SA: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  10. Agronomie Africaine: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  11. Mathematics Connection: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  12. Critical Arts: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  13. Rwanda Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  14. Kenya Veterinarian: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  15. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo

    2015-01-01

    introductory to specialized, and from authoritative to speculative or opinionated, when to show what sources of information? How does the information seeking process evolve and what are relevant differences between different stages? With complex task and search process management, blending searching, browsing...

  16. Innovation: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  17. Distributed Deep Web Search

    NARCIS (Netherlands)

    Tjin-Kam-Jet, Kien

    2013-01-01

    The World Wide Web contains billions of documents (and counting); hence, it is likely that some document will contain the answer or content you are searching for. While major search engines like Bing and Google often manage to return relevant results to your query, there are plenty of situations in

  18. Search and switching costs

    NARCIS (Netherlands)

    Siekman, Wilhelm Henricus

    2016-01-01

    This thesis analyses markets with search and with switching costs. It provides insights in several important issues in search markets, including how loss aversion may affect consumer behavior and firm conduct, and how prices, welfare, and profits may change when an intermediating platform orders

  19. Human memory search

    NARCIS (Netherlands)

    Davelaar, E.J.; Raaijmakers, J.G.W.; Hills, T.T.; Robbins, T.W.; Todd, P.M.

    2012-01-01

    The importance of understanding human memory search is hard to exaggerate: we build and live our lives based on what whe remember. This chapter explores the characteristics of memory search, with special emphasis on the use of retrieval cues. We introduce the dependent measures that are obtained

  20. ElasticSearch cookbook

    CERN Document Server

    Paro, Alberto

    2015-01-01

    If you are a developer who implements ElasticSearch in your web applications and want to sharpen your understanding of the core elements and applications, this is the book for you. It is assumed that you've got working knowledge of JSON and, if you want to extend ElasticSearch, of Java and related technologies.

  1. Annales Aequatoria: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  2. Searching low and high

    DEFF Research Database (Denmark)

    Laursen, Keld; Salter, Ammon

    2003-01-01

    .The results suggest that firms who adopt `open' search strategies and invest in R&D are morelikely than other firms to draw from universities, indicating that managerial choice matters inshaping the propensity of firms to draw from universities.Key words: University-industry links, innovation, external search...

  3. Lexikos: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  4. Kiswahili: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  5. Philosophical Papers: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  6. Sciences & Nature: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  7. Counsellor (The): Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  8. Nigerian Libraries: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  9. Vulture News: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  10. Afrika Statistika: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  11. Acta Theologica: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  12. Water SA: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  13. Tropical Veterinarian: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  14. African Environment: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  15. Zede Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  16. Africa Insight: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  17. African Zoology: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  18. Searches for Supersymmetry

    CERN Document Server

    Ventura, Andrea; The ATLAS collaboration

    2017-01-01

    New and recent results on Supersymmetry searches are shown for the ATLAS and the CMS experiments. Analyses with about 36 fb$^{-1}$ are considered for searches concerning light squarks and gluinos, direct pair production of 3$^{rd}$ generation squarks, electroweak production of charginos, neutralinos, sleptons, R-parity violating scenarios and long-lived particles.

  19. Search and Disrupt

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders

    This paper analyzes how external search is affected by strategic interest alignment among knowledge sources. I focus on misalignment arising from the heterogeneous effects of disruptive technologies by analyzing the influence of incumbents on 2,855 non-incumbents? external knowledge search efforts....... The efforts most likely to solve innovation problems obtained funding from the European Commission?s 7th Framework Program (2007-2013). The results show that involving incumbents improves search in complementary technologies, while demoting it when strategic interests are misaligned in disruptive technologies....... However, incumbent sources engaged in capability reconfiguration to accommodate disruption improve search efforts in disruptive technologies. The paper concludes that the value of external sources is contingent on more than their knowledge. Specifically, interdependence of sources in search gives rise...

  20. Cortical Visual Impairment

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased ...