The evidence from previous studies showed that frequent exposure to violent media or circumstances affects an individual’s desensitization to violence, aggression, remorse, and leads to psychopathy in adult life. However, studies of a recidivist’s brain activity have not been much explored. Thai male students (N=43) aged 18–35 years were included. The male recidivist group participated in violent circumstances of two or more times. Both recidivists (n=21) and non-recidivists (n=22) were undergone ERP recording while conducting the three series of tasks. The target ERP generated in these tasks were the P300 wave recorded over Pz electrode sites. The recidivists showed significantly smaller P300 amplitude than the non-recidivists when responding to target stimuli in three series of tasks. In addition, the recidivists had significantly higher score of physical aggression, uncaring, and callousness than the non-recidivists. Reduced P300 amplitude correlated to high physical aggression, uncaring, and callousness on the recidivist group.
