Top-down search strategies cannot override attentional capture.

Bacon and Egeth (1994) have claimed that color singletons do not interfere with search for a shape singleton when, instead of using a singleton detection mode, participants are forced to use a feature search mode. Bacon and Egeth induced a feature search mode by adding different shape singletons to the display so that observers could not simply respond to uniqueness to find the target. We did exactly the same but used larger display sizes to ensure that the target and distractor singletons remained salient. The results show that under these conditions, an irrelevant color singleton interferes with search for a shape singleton. It is argued that the notion of differential search modes may be incorrect and that the results can be explained in terms of bottom-up salience signals.