['A simple distractor elicits a large P3 when the standard and target are difficult to discriminate in the three-stimulus oddball paradigm. This study investigated whether the distractor P3 reflects attentional capture by stimulus deviance or cognitive interference with maintaining the standard representation.', 'Event-related brain potentials were recorded from 12 participants who performed a visual three-stimulus oddball paradigm. Four task conditions were defined by a combination of two presentation types of distractor stimuli (central or bilateral) and two levels of standard/target discrimination difficulty (easy or difficult). Bilateral distractors had stimulus deviance but did not interfere with maintenance of the standard representation.', 'Central distractors elicited a P3, the amplitude of which was larger in the difficult task than in the easy task. In contrast, bilateral distractors elicited a large P3 in both the easy and difficult tasks.'] Is distractor P3 associated with attentional capture by stimulus deviance?