Informative cues can slow search: the cost of matching a specific template

During visual search, observers hold in mind a search template, which they match against the stimulus. To characterize the content of this template, we trained observers to discriminate a set of artificial objects at an individual level and at a category level. The observers then searched for the objects on backgrounds that camouflaged the features that defined either the object's identity or the object's category. Each search stimulus was preceded by the target's individual name, its category name, or an uninformative cue. The observers' task was to locate the target, which was always present and always the only figure in the stimulus. The results showed that name cues slowed search when the features associated with the name were camouflaged. Apparently, the observers required a match between their mental representation of the target and the stimulus, even though this was unnecessary for the task. Moreover, this match involved all distinctive features of the target, not just the features necessary for a definitive identification. We conclude that visual search for a specific target involves a verification process that is performed automatically on all of the target's distinctive features.