Searching for visual singletons without a feature to guide attention

Resource type
Date created
2022-10-01
Authors/Contributors
Abstract
RT studies have provided evidence for a singleton-detection strategy that is used to search for salient targets when there is no additional featural knowledge that would help guide attention. Despite this behavioral evidence, there have been few ERP studies of singleton detection mode because it was reported early on that the ERP signature of attentional selection (the N2pc) is absent without feature guidance. Recently, however, it was discovered that a small and relatively late N2pc occurs in singleton detection mode along with a previously unreported component called the singleton detection positivity (SDP). Here, we show that both components are influenced by the number of items in the display, as one might expect in a salience-based search mode. Specifically, the N2pc and SDP were larger when the set size was increased to make the singleton “pop out” more easily, when participants responded more quickly regardless of set size, and when RT search slopes were negative (Experiment 1). The latency of the SDP also depended on set size. In Experiment 2, EEG was recorded with a higher density electrode array to better characterize the scalp topography of the components and to estimate their neural sources. Regional sources near the ventral surface of extrastriate cortex in the occipital lobe explained over 96% of N2pc and SDP activities. These results indicate that searching in singleton detection mode selectively modulates processing within perceptual regions of visual cortex.
Document
Identifier
DOI: 10.1162/jocn_a_01890
Publication details
Publication title
Journal of Cognitive Neuroscience
Document title
Searching for visual singletons without a feature to guide attention
Publisher
MIT Press
Date
2022-10-01
Volume
34
Issue
11
First page
2127
Last page
2143
Publisher DOI
Copyright statement
Copyright is held by the author(s) with limited rights held by the publisher of the final publication.
Scholarly level
Peer reviewed?
Yes
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