The electrophysiological locus of the redundant target effect on visual discrimination in a dual singleton search task.
Task performance can be enhanced by the addition of extra information to a visual environment in which observers search for a target stimulus. One example of such information is the repetition of the searched-for stimulus; a form of target redundancy. In the present study, the electrophysiological correlates of such target redundancy were investigated in a visual discrimination task. Observers were asked to look for targets in displays that always contained two salient singletons (tilted lines; targets and/or nontargets) against a background of vertical distractor lines. Displays contained either two redundant targets, two nontargets, or a single target and nontarget, at opposite sides of the visual field. Search was most efficient when two targets were shown, and effects of target redundancy were observed on the event-related potential as well. Target redundancy modulated the anterior N2, and the P3 in both an early and a late window. The results are compatible with models of visual attention that support a relatively late (i.e., central or decisional) locus of redundancy processing.
Ludwig Maximilian University Munich, Germany; University of Groningen, The Netherlands. Electronic address: e.g.akyurek@rug.nl.
Elkan G
EG
Akyürek
Anna
A
Schubö
D000328:Adult; D001288:Attention / Q000502:physiology; D055724:Electrophysiological Phenomena / Q000502:physiology*; D005071:Evoked Potentials / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time; D013647:Task Performance and Analysis; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
Event-related potential; N2a; P3; Redundancy gain; Visual attention