“Thou Shalt Kill”: Practicing self-control supports adherence to personal values when asked to aggress

Poor self-control is a root cause of aggression and criminality. But people can improve their self-control through repetitive practice. Because self-control involves acting in accordance with personal values, practicing self-control can promote attainment of value-consistent goals. The present research tested the hypothesis that practicing self-control could both decrease and increase obedient aggression. In Experiment 1, relative to the active control group, participants who practiced self-control were more hesitant to engage in mock violence (e.g., “cutting” the experimenter's throat with a rubber knife), especially for participants high in dispositional empathy. In Experiment 2, practicing self-control increased obedience to kill insects, but only among participants who felt little moral responsibility for their actions. There was a trend for decreased killing among participants who felt morally responsible for their actions. Our findings suggest that when asked to behave aggressively, self-control promotes adherence to personal values, which may or may not fuel aggression.