Response Selection Modulates Visual Search Within and Across Dimensions.

In feature search tasks, uncertainty about the dimension on which targets differ from the nontargets hampers search performance relative to a situation in which this dimension is known in advance. Typically, these cross-dimensional costs are associated with less efficient guidance of attention to the target. In the present study, participants either had to perform a feature search task or had to perform a nonsearch task, that is, respond to a target presented without nontargets. The target varied either in one dimension or across dimensions. The results showed similar effects both in search and nonsearch conditions: Preknowledge of the target dimension gave shorter response times than when the dimension was unknown. Similar results were found using a trial-by-trial cueing. It is concluded that effects that typically have been attributed to early top-down modulation of attentional guidance may represent effects that occur later in processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatiotemporal Segregation in Visual Search: Evidence From Parietal Lesions.

The mechanisms underlying segmentation and selection of visual stimuli over time were investigated in patients with posterior parietal damage. In a modified visual search task, a preview of old objects preceded search of a new set for a target while the old items remained. In Experiment 1, control participants ignored old and prioritized new items, but patients had severe difficulties finding the target (especially on the contralesional side). In Experiment 2, simplified displays yielded analogous results, ruling out search ease as a crucial factor in poor preview search. In Experiment 3, outlines around distractor groups (to aid segmentation) improved conjunction but not preview search, suggesting a specific deficit in spatiotemporal segmentation. Experiment 4 ruled out spatial disengagement problems as a factor. The data emphasize the role of spatiotemporal segmentation cues in preview search and the parietal lobe in the role of these cues to prioritize search of new stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual Search Asymmetry With Uncertain Targets.

The underlying mechanism of search asymmetry is still unknown. Many computational models postulate top-down selection of target-defining features as a crucial factor. This feature selection account implies, and other theories implicitly assume, that predefined target identity is necessary for search asymmetry. The authors tested the validity of the feature selection account using a singleton search task without a predefined target. Participants conducted a target-defined and a singleton search task with a circle (O) and a circle with a vertical bar (Q). Search asymmetry was observed in both tasks with almost identical magnitude. The results were not due to trial-by-trial feature selection, because search asymmetry persisted even when the target was completely unpredictable. Asymmetry in the singleton search was also observed with more complex stimuli, Kanji characters. These results suggest that feature selection is not necessary for search asymmetry, and they impose important constraints on current visual search theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel Processing in Visual Search Asymmetry.

The difficulty of visual search may depend on assignment of the same visual elements as targets and distractors-search asymmetry. Easy C-in-O searches and difficult O-in-C searches are often associated with parallel and serial search, respectively. Here, the time course of visual search was measured for both tasks with speed-accuracy methods. The time courses of the 2 tasks were similar and independent of display size. New probabilistic parallel and serial search models and sophisticated-guessing variants made predictions about time course and accuracy of visual search. The probabilistic parallel model provided an excellent account of the data, but the serial model did not. Asymptotic search accuracies and display size effects were consistent with a signal-detection analysis, with lower variance encoding of Cs than Os. In the absence of eye movements, asymmetric visual search, long considered an example of serial deployment of covert attention, is qualitatively and quantitatively consistent with parallel search processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prioritized Selection in Visual Search Through Onset Capture and Color Inhibition: Evidence From a Probe-Dot Detection Task.

Observers performed a preview search task in which, on some trials, they had to indicate the presence of a briefly presented probe-dot. Probes could be presented on locations corresponding to old or new elements and prior to or after the presentation of the new elements. After the presentation of the new elements, probes were generally detected faster on new than on old locations, indicating prioritized selection of new elements. Prior to the presentation of the new elements, probes were detected faster on new than on old locations only when old and new elements differed in color. These results suggest that prioritized selection of new elements is mediated not by visual marking but by onset capture. Additionally, observers may apply color-based inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When a reappearance is old news: Visual marking survives occlusion.

Performance in a visual search task becomes more efficient if half of the distractors are presented before the rest of the stimuli. This "preview benefit" may partly be due to inhibition of the old (previewed) items. The preview effect is abolished, however, if the old items offset briefly before reappearing (D. G. Watson & G. W. Humphreys, 1997). The authors examined whether this offset effect still occurred if the old item undergo occlusion. Results show that a preview benefit was found when the old items were occluded but not otherwise, consistent with the idea of top-down attentional inhibition being applied to the old items. The preview benefit is attenuated, however, by movement of the irrelevant stimuli in the displays. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Costs of Changing the Representation of Action: Response Repetition and Response-Response Compatibility in Dual Tasks.

In 5 experiments, the authors investigated the costs associated with repeating the same or a similar response in a dual-task setting. Using a psychological refractory period paradigm, they obtained response-repetition costs when the cognitive representation of a specific response (i.e., the category-response mapping) changed (Experiment 1) but benefits when it did not change (Experiment 2). The analogous pattern of results was found for conceptually similar (i.e.. compatible) responses. Response-response compatibility costs occurred when the cognitive representations of the compatible responses were different (Experiments 3A & 3B), but compatibility benefits occurred when they were the same (Experiment 4). The authors interpret the costs of repeating an identical or compatible response in terms of a general mechanism of action selection that involves coding the task-specific meaning of a response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-Related Preservation of Top-Down Attentional Guidance During Visual Search.

Younger (19-27 years of age) and older (60-82 years of age) adults performed a letter search task in which a color singleton was either noninformative (baseline condition) or highly informative (guided condition) regarding target location. In the guided condition, both age groups exhibited a substantial decrease in response time (RT) to singleton targets, relative to the baseline condition, as well as an increase in RT to nonsingleton targets. The authors conclude that under conditions that equate the physical structure of individual displays, top-down attentional guidance can be at least as effective for older adults as for younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual search for orientation among heterogeneous distractors: Experimental results and implications for signal-detection theory models of search.

Three experiments tested a signal-detection theory (SDT) model of visual search (e.g., as described in J. Palmer, C. T. Ames, & D. T. Lindsey, 1993). In Experiment 1, participants searched for a 0° line among distractors at (a) 30°; (b) ? at 30°, ? at 50°; (c) ? at 30°, 50°, and 70°; and (d) ? at 30°, ? at 70°. The SDT model predicts improved performance in the more heterogeneous conditions, as some distractors are more discriminable from the target. In contrast, in Experiment 1 human performance degraded in the more heterogeneous conditions (c and d). In Experiment 2, sparser displays improved the performance of the SDT model. In Experiment 3, search for θ° among homogeneous θ?+?20° distractors was compared with search for θ° among θ?±?20° distractors. Performance in the latter condition was often worse, relative to performance in the homogeneous condition, than predicted by the SDT model; however, this depended greatly on the identity of the target. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual Search and the Collapse of Categorization.

Categorization researchers typically present single objects to be categorized. But real-world categorization often involves object recognition within complex scenes. It is unknown how the processes of categorization stand up to visual complexity or why they fail facing it. The authors filled this research gap by blending the categorization and visual-search paradigms into a visual-search and categorization task in which participants searched for members of target categories in complex displays. Participants have enormous difficulty in this task. Despite intensive and ongoing category training, they detect targets at near-chance levels unless displays are extremely simple or target categories extremely focused. These results, discussed from the perspectives of categorization and visual search, might illuminate societally important instances of visual search (e.g., diagnostic medical screening). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Role of Fear-Relevant Stimuli in Visual Search: A Comparison of Phylogenetic and Ontogenetic Stimuli.

It has been argued that phylogenetic fear-relevant stimuli elicit preattentive capture of attention. To distinguish between fear relevance and time of appearance in evolutionary history, the authors compare phylogenetic and ontogenetic fear-relevant and fear-irrelevant stimuli in a visual search task. The authors found no evidence for a special role of phylogenetic fear-relevant stimuli; it seems that fear relevance in general is more important than is the evolutionary age. The pattern of results indicates that attention toward threatening stimuli is mainly affected by a late component that prolongs the disengagement of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual marking: Dissociating effects of new and old set size.

Visual marking makes it possible to ignore old items during search. In a typical study, old items are previewed 1 s before adding an equal number of new items, one of which is the target. Previewing half of the items reduces the search slope relating response time (RT) to overall set size by half. However, this manipulation sometimes only reduces overall RT but not search slope (Experiment 1). By orthogonally varying the numbers of old and new items, Experiment 2 shows that old and new set sizes interactively affect visual marking. Given a constant new set size, the size of the old set has negligible effect on RT. However, increasing the new set size reduces the preview benefit in overall RT. Experiment 3 shows that this reduction may be restricted to paradigms that use temporal segregation cues. Studies should vary old and new set size orthogonally to avoid missing a visual marking effect where one may be present. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Panoramic Search: The Interaction of Memory and Vision in Search Through a Familiar Scene.

How do observers search through familiar scenes? A novel panoramic search method is used to study the interaction of memory and vision in natural search behavior. In panoramic search, observers see part of an unchanging scene larger than their current field of view. A target object can be visible, present in the display but hidden from view, or absent. Visual search efficiency does not change after hundreds of trials through an unchanging scene (Experiment 1). Memory search, in contrast, begins inefficiently but becomes efficient with practice. Given a choice between vision and memory, observers choose vision (Experiments 2 and 3). However, if forced to use their memory on some trials, they learn to use memory on all trials, even when reliable visual information remains available (Experiment 4). The results suggest that observers make a pragmatic choice between vision and memory, with a strong bias toward visual search even for memorized stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Color Grouping in Space and Time: Evidence From Negative Color-Based Carryover Effects in Preview Search.

Five experiments addressed the role of color grouping in preview search (D. G. Watson & G. W. Humphreys, 1997). Experiment 1 used opposite color ratios of distractors in preview and second search displays, creating equal numbers of distractors in each color group in the final display. There was selective slowing for new targets carrying the majority color of the old items. This effect held when there was no bias in the preview and only the second search set had an uneven color ratio (Experiment 2). In Experiment 3, participants had foreknowledge of the target color, and effects were shown over and above those due to color biases. Experiment 4 demonstrated negative color carryover even when previews changed color. Experiment 5 showed reduced color carryover effects when previews were presented more briefly. Collectively, the results provide evidence for inhibitory carryover effects in preview search based on feature grouping. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual Search Across the Life Span.

Gains and losses in visual search were studied across the life span in a representative sample of 298 individuals from 6 to 89 years of age. Participants searched for single-feature and conjunction targets of high or low eccentricity. Search was substantially slowed early and late in life, age gradients were more pronounced in conjunction than in feature search, and all age groups were uniformly affected by eccentricity manipulations. However, developmental and aging trends were distinctly asymmetrical: Children's performance was particularly affected by the mere presence of distractors; whereas in late life, performance was particularly impaired on target-absent trials and with increasing numbers of distractors. The implications for life span theories of cognitive and attentional development and for cognitive-speed and inhibitory-control accounts are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feature-based memory-driven attentional capture: Visual working memory content affects visual attention.

In 7 experiments, the authors explored 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. The presence of singleton distractors interfered more strongly with a visual search task when it was accompanied by an additional memory task. Singleton distractors interfered even more when they were identical or related to the object held in memory, but only when it was difficult to verbalize the memory content. Furthermore, this content-specific interaction occurred for features that were relevant to the memory task but not for irrelevant features of the same object or for once-remembered objects that could be forgotten. Finally, memory-related distractors attracted more eye movements but did not result in longer fixations. The results demonstrate memory-driven attentional capture on the basis of content-specific representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Visual marking: Dissociating effects of new and old set size": Erratum.

Reports an error in the byline of the article by Y. Jiang et al (Journal of Experimental Psychology: Learning, Memory, and Cognition, 2002[Mar], Vol 28[2], 293-302). Y. Jiang's affiliations should have been listed as "Yale University and John B. Pierce Laboratory" and Lawrence E. Mark's affiliations should have been listed as "John B. Pierce Laboratory and Yale University." (The following abstract of the original article appeared in record 2002-00620-003.) Visual marking makes it possible to ignore old items during search. In a typical study, old items are previewed 1 s before adding an equal number of new items, one of which is the target. Previewing half of the items reduces the search slope relating response time (RT) to overall set size by half. However, this manipulation sometimes only reduces overall RT but not search slope (Experiment 1). By orthogonally varying the numbers of old and new items, Experiment 2 shows that old and new set sizes interactively affect visual marking. Given a constant new set size, the size of the old set has negligible effect on RT. However, increasing the new set size reduces the preview benefit in overall RT. Experiment 3 shows that this reduction may be restricted to paradigms that use temporal segregation cues. . . . (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual Search for Object Orientation Can Be Modulated by Canonical Orientation.

The authors studied the influence of canonical orientation on visual search for object orientation. Displays consisted of pictures of animals whose axis of elongation was either vertical or tilted in their canonical orientation. Target orientation could be either congruent or incongruent with the object's canonical orientation. In Experiment 1, vertical canonical targets were detected faster when they were tilted (incongruent) than when they were vertical (congruent). This search asymmetry was reversed for tilted canonical targets. The effect of canonical orientation was partially preserved when objects were high-pass filtered, but it was eliminated when they were low-pass filtered, rendering them as unfamiliar shapes (Experiment 2). The effect of canonical orientation was also eliminated by inverting the objects (Experiment 3) and in a patient with visual agnosia (Experiment 4). These results indicate that orientation search with familiar objects can be modulated by canonical orientation, and they indicate a top-down influence on orientation processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Role of Stimulus-Driven and Goal-Driven Control in Saccadic Visual Selection.

Four experiments were conducted to investigate the role of stimulus-driven and goal-driven control in saccadic eye movements. Participants were required to make a speeded saccade toward a predefined target presented concurrently with multiple nontargets and possibly 1 distractor. Target and distractor were either equally salient (Experiments 1 and 2) or not (Experiments 3 and 4). The results uniformly demonstrated that fast eye movements were completely stimulus driven, whereas slower eye movements were goal driven. These results are in line with neither a bottom-up account nor a top-down notion of visual selection. Instead, they indicate that visual selection is the outcome of 2 independent processes, one stimulus driven and the other goal driven, operating in different time windows. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol-Induced Impairment of Inhibitory Mechanisms Involved in Visual Search.

The present study examined the effects of alcohol on the ability to perform a cued target detection task that measured inhibition of return (IOR). IOR is a reflexive inhibitory mechanism that delays attention from returning to a previously attended location and has been shown to increase the efficiency of a visual search. Ten social drinkers performed the task under 3 alcohol doses: 0.0 g/kg (placebo), 0.45 g/kg, and 0.65 g/kg. The results showed both active alcohol doses reduced the IOR effect by shortening its duration of influence. The reduced duration of IOR under alcohol suggests that repeated searches in previously explored locations might be more likely under the drug, thereby reducing search efficiency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)