Re-examining electrophysiological evidence for proactive suppression of salient visual distractors

Salient-but-irrelevant color singletons often elicit a positive component in the event-related potential (the P_D) rather than a negative component associated with attentional selection (the N2pc). The positivity is often assumed to reflect inhibitory control processes that prevent salience-driven distraction, particularly when the positivity emerges before the time range of the N2pc. To be certain that this "early P_D" is associated with inhibition, it is necessary to show that the positivity is absent when participants search for the color singleton. Here, we replicated a seminal letter-search task in which a singleton distractor was found to elicit an early positivity (Experiment 1) and then instructed participants to detect the presence of the same singleton (Experiment 2). We discovered that the early positivity is present both when participants ignored the singleton and when they searched for the singleton. These results suggest that the early positivity is associated with salience processing rather than inhibition that prevents distraction.