1. The purpose of the present study was to determine the cognitive psychophysiological correlates of impulsive aggression in a "high" functioning sample: college students. 2. Visual P300 was measured during a standard oddball task and a surprise task that included unexpected low probability stimuli. 3. Results indicated significantly reduced P300 amplitude and prolonged latency for impulsive aggressive subjects to target stimuli on the standard task. Target amplitude differences where further augmented under conditions involving unexpected stimuli although no significant latency differences were observed. The topography of P300 amplitude to unexpected stimuli differed from that of the target. 4. Topographic group differences found for unexpected stimuli are suggestive of cognitive processing deficits previously demonstrated using neuropsychological techniques in impulsive aggressive individuals.