The neural basis of attentional control in visual search

Journal of Experimental Psychology: Human Perception and Perfor

2016

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Publisher's copyright statement:c 2016 APA, all rights reserved. This article may not exactly replicate the nal version published in the APA journal. It is not the copy of record.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe question whether alphanumerical category is involved in the control of attentional target selection during visual search remains a contentious issue. We tested whether category-based attentional mechanisms would guide the allocation of attention under conditions where targets were defined by a combination of alphanumerical category and a basic visual feature, and search displays could contain both targets and partially matching distractor objects. The N2pc component was employed as an electrophysiological marker of attentional object selection in tasks where target objects were defined by a conjunction of color and category (Experiment 1) or shape and category (Experiment 2).Some search displays contained the target or a nontarget object that matched either the target color/shape or its category among three non-matching distractors. In other displays, the target and a partially matching nontarget object appeared together. N2pc components were elicited not only by targets and by color-or shape-matching nontargets, but also by category-matching nontarget objects, even on trials where a target was present in the same display. On these trials, the summed N2pc components to the two types of partially matching nontargets were initially equal in size to the target N2pc, suggesting that attention was allocated simultaneously and independently to all objects with target-matching features during the early phase of attentional processing. Results demonstrate that alphanumerical category is a genuine guiding feature that can operate in parallel with color or shape information to control the deployment of attention during visual search.Keywords: selective attention, visual search, category-based attentional control, eventrelated brain potentials, feature-based attention, object-based attention 3 3

Section: Discussionmentioning

confidence: 99%

Category-based guidance of spatial attention during visual search for feature conjunctions.

Nako

Grubert

Journal of Experimental Psychology: Human Perception and Perfor

2016

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“…On single-target trials, difference waveforms returned to baseline, before a second contralateral negativity started to emerge. This later effect marks the onset of the sustained posterior contralateral negativity (SPCN component) that typically follows the N2pc and is assumed to reflect the attentional activation of target representations in visual working memory (e.g., Mazza, Turatto, Umilta, & Eimer, 2007; see also Eimer, 2014, for further discussion). On dual-target trials, the contralateral negativity during the N2pc time window did not return to baseline at around 350 ms post-stimulus, but remained present in a sustained fashion during the post-N2pc time interval.…”

Section: Discussionmentioning

confidence: 99%

“…The N2pc is a lateralised ERP component that marks the allocation of focal attention to candidate target objects in visual search (e.g., Luck & Hillyard, 1994;Eimer, 1996;Woodman & Luck, 1999). This component typically emerges 180-200 ms after stimulus onset at posterior electrodes contralateral to the visual field where a possible target object is presented, is generated in extrastriate areas of the ventral visual stream (Hopf et al, 2000), and is assumed to reflect the spatially selective enhancement of visual processing at particular retinotopic locations within these areas (see Eimer, 2014Eimer, , 2015. In most N2pc studies of attentional target selection, stimulus displays contain a single candidate target object among multiple task-irrelevant distractors.…”

mentioning

confidence: 99%

Rapid attentional selection processes operate independently and in parallel for multiple targets

Grubert

2016

Biological Psychology

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe question whether multiple objects are selected serially or in parallel remains contentious. Previous studies employed the N2pc component as a marker of attentional

“…This article will discuss the cognitive and neural mechanisms that are responsible for our ability to find known target objects at uncertain locations. Some of the ideas developed here have been previously summarized in a brief review article (Eimer, 2014).…”

Section: Introductionmentioning

confidence: 99%

EPS Mid-Career Award 2014

Quarterly Journal of Experimental Psychology

2015

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In visual search, observers try to find known target objects among distractors in visual scenes where the location of the targets is uncertain. This review article discusses the attentional processes that are active during search and their neural basis. Four successive phases of visual search are described. During the initial preparatory phase, a representation of the current search goal is activated. Once visual input has arrived, information about the presence of target-matching features is accumulated in parallel across the visual field (guidance). This information is then used to allocate spatial attention to particular objects (selection), before representations of selected objects are activated in visual working memory (recognition). These four phases of attentional control in visual search are characterized both at the cognitive level and at the neural implementation level. It will become clear that search is a continuous process that unfolds in real time. Selective attention in visual search is described as the gradual emergence of spatially specific and temporally sustained biases for representations of task-relevant visual objects in cortical maps.3