The impact of rumination on aggressive thoughts, feelings, arousal, and behaviour.

Although rumination following a provocation can increase aggression, no research has examined the processes responsible for this phenomenon. With predictions derived from the General Aggression Model, three experiments explored the impact of two types of post-provocation rumination on the processes whereby rumination augments aggression. In Experiment 1, relative to distraction, self-focused rumination uniquely increased the accessibility of arousal cognition, whereas provocation-focused rumination uniquely amplified the accessibility of aggressive action cognition. In Experiment 2, provocation-focused rumination uniquely increased systolic blood pressure. In Experiment 3, both types of rumination increased aggressive behaviour relative to a distraction condition. Angry affect partially mediated the effects of both provocation- and self-focused rumination on aggression. Self-critical negative affect partially mediated the effect of self-focused rumination but not provocation-focused rumination. These findings suggest that provocation-focused rumination influences angry affect, aggressive action cognition, and cardiovascular arousal, whereas self-focused rumination increases self-critical negative affect, angry affect, and arousal cognition. These studies enhance our understanding of why two types of post-provocation rumination increase aggressive behaviour.