An electrophysiological investigation of the cognitive processes underlying provoked aggression in humans
Recently, the event-related potential (ERP) technique has been applied to questions of social information processing. Several studies have examined standard and social information processing variables in aggressive individuals, but little is known about the neurophysiological processes that take place in real-time during an aggressive encounter. In this study, 48 men and women high and low in aggression history exchanged noise blasts of varying intensity with a (fictitious) opponent in a modified version of a well-validated laboratory-controlled behavioral measure of aggression, the Taylor Reaction-time Task (Taylor, 1967), while ERPs were simultaneously being recorded at scalp sites. Mixed model ANOVAs were used to analyze differences between aggressive and non-aggressive men and women in the neurophysiological processes related to perceiving provocation and responding to threat. Dependent variables included mean amplitude and latency for the following ERP components: P3 (to provocation), N2, No-Go P3, N450, and the negative slow wave (NSW). Aggressive participants were more likely to make errors in identifying the high provocation stimuli while non-aggressive participants were not. Non-aggressive participants showed greater and slower processing of provocative stimuli as evidenced by larger P3 amplitude and later P3 peak. During the aggression trials, aggressive participants were more likely to administer a "high" noise blast to the opponent under conditions of low provocation. Both the aggressive and non-aggressive groups made greater use of the "high" noise blast following high provocation. Effects were also observed for components previously linked to inhibitory processes (N2, No-Go P3, N450, and NSW). The results suggest that aggressive and non-aggressive individuals process personally relevant threat information differently. More research is needed to understand how ERP components putatively linked to inhibitory cognitive processes relate to aggression in real-world encounters. Further implications and future directions are discussed.