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.
Department of Cognitive Psychology, Vrije Universiteit, Van der Boechorststraat 1, 1081 BT Amsterdam, Netherlands. k.mortier@psy.vu.nl
Karen
K
Mortier
Jan
J
Theeuwes
Peter
P
Starreveld
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001288:Attention; D003463:Cues; D004192:Discrimination, Psychological; D006801:Humans; D011582:Psychological Theory; D011930:Reaction Time; D035501:Uncertainty; D014796:Visual Perception