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Updated: Feb 3, 2026

Methods to Test Visual Attention Online
Published on: February 19, 2015
Electrophysiological correlates of active suppression and attentional selection in preview visual search
1Department of Psychological Sciences, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK.
Abstract:
Advance preview of a subset of distractor objects improves the efficiency of visual search performance, but the causes and mechanisms of such preview benefits remain unclear. Here, we employed event-related potential (ERP) markers of the selective processing of preview displays and full search displays in lateralised preview search tasks where only one side of the search displays was task-relevant. Preview displays elicited a sustained positivity contralateral to the relevant side (PD component), indicative of the active suppression of distractor objects on this side. Lateralised ERP components to full search displays revealed qualitative differences between attentional selection processes on preview as compared to no-preview trials. When search displays were preceded by preview displays, attention was directly allocated to target objects, while distractors remained unattended. When all search display objects were presented simultaneously (no-preview), attention was directed non-selectively to objects on the task-relevant side, even when no target was present. These results suggest that behavioural preview effects in visual search can be accounted for by the inhibition of previewed distractors, and the subsequent rapid attentional selection of target objects on preview trials.
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