Revisiting the category effect: the influence of meaning and search strategy on the efficiency of visual search.

A series of experiments evaluated whether the category membership of objects influences the efficiency of visual search (the category effect). Participants were trained to associate meaningful verbal labels with simple shapes so that it was possible to vary the categorical relationship between targets and distractors in the search displays while counterbalancing for the visual similarity of the targets and distractors. Participants were instructed (a) to simply search for the unique item in the displays, (b) to search for the unique item while adopting an active search strategy or (c) to search for the unique item while adopting a passive search strategy. The efficiency of search for targets embedded among distractors from the same category or different category was assessed in terms of the slopes of the search functions for detecting the targets. The results showed that the categorical relationship between targets and distractors influences the efficiency of visual search when participants adopt a passive search strategy but not when participants adopt an active search strategy.