On the precision of goal-directed attentional selection.

Attention selects objects in a scene for cognitive processing. A growing body of evidence has been used to argue that observers are able to narrowly restrict attentional selection to stimuli that match a feature-based target template while ignoring similar-looking distractors. For example, visual search for a target among feature-similar nontargets is highly efficient. Here, I demonstrate that observers are substantially impaired at selecting a target among feature-similar nontargets when stimuli are compared with a target template serially in time. The results argue that goal-directed attentional selection is distinctly imprecise, and that comparing stimuli with a target template reflects an inefficient mechanism of selection that cannot fully explain visual search performance under demanding conditions.