Distraction by color and its electrophysiological correlates.

We used the effects of colored distractors on ERPs to assess the psychophysiological consequences of selection by color. In Experiment 1 participants searched a rapid serial visual presentation (RSVP) sequence for a prespecified target letter that usually appeared in a cued color. ERPs elicited by cued-color distractors were similar to those elicited by targets, indicating relatively complete distractor processing. In Experiment 2 one letter in the RSVP sequence was framed by an irrelevant distractor probe in either the cued color or an uncued color. Such distractor probes elicited a P1, N1, or P2 sequence that depended on their color. In addition, probes presented shortly before the target tended to suppress the ERP components associated with target processing, especially for probes in the cued color. These observed variations in ERPs depending on the distractor's type and its distance from the target help to reveal the time course and mechanisms of selection by color.