Colour-cueing in visual search

Several studies have shown that people can selectively attend to stimulus c olour. e.g., in visual search. and that preknowledge of a target colour can improve response speed/accuracy, The purpose was to use a form-identificat ion task to determine whether valid colour precues can produce benefits and invalid cues costs. The subject had to identify the orientation of a "T"-s haped element in a ring of randomly-oriented -"L"-s when either two or four or the elements were differently coloured. Contrary to Moore and Egeth's ( 1998) recent findings, colour-based attention did affect performance under data-limited conditions: Colour cues produced benefits when processing load was high; when the load was reduced, they incurred only costs. Surprisingl y, a valid colour cue succeeded in improving performance in the high-load c ondition even when its validity was reduced to the chance level. Overall. t he results suggest that knowledge of a target colour does not facilitate th e processing of the target, but makes it possible to prioritize it.