Taming the White Bear: Initial Costs and Eventual Benefits of Distractor Inhibition.

Previous research indicates that prior information about a target feature, such as its color, can speed search. Can search also be speeded by knowing what a target willnotlook like? In the two experiments reported here, participants searched for target letters. Prior to viewing search displays, participants were prompted either with the color in which one or more nontarget letters would appear (ignore trials) or with no information about the search display (neutral trials). Critically, when participants were given one consistent color to ignore for the duration of the experiment, compared with when they were given no information, there was a cost in reaction time (RT) early in the experiment. However, after extended practice, RTs on ignore trials were significantly faster than RTs on neutral trials, which provides a novel demonstration that knowledge about nontargets can improve search performance for targets. When the to-be-ignored color changed from trial to trial, no RT benefit was observed.