An ERP study of target competition: individual differences in functional impulsive behavior.

The present event-related potential (ERP) study aimed at investigating the specific behavioral and electrophysiological correlates of target competition, and their relationships to individual differences in functional impulsivity. Twenty-two participants performed a modified XO task with two conditions. Target competition displays included one up to three identical targets and no distractor, whereas distractor competition displays always included one target among one up to three distractors. On every trial, (one of) the target(s) had to be localized. Behavioral data revealed response time (RT) increases with increasing number of stimuli in both conditions. P2, N2, and P3 components were specifically responsive to target competition. High functional impulsives showed larger P2 for multiple- compared to single-target displays, but no effects on N2, P3, and RT. By contrast, in low functional impulsives target competition led to N2 increase, P3 decrease, and RT increase, while P2 effects were absent. Findings suggest that functional impulsives are better able to adapt to task requirements; in the present task they avoided conflict from multiple-target displays through better target discrimination at early stages of processing.