Using an adapted form of the Taylor competitive reaction time task (TCRT: Taylor, 1967), we examined the effect of initially non-aggressive behaviour during aggressive encounters. Specifically, if a person is initially non-aggressive, but becomes more aggressive later, does an opponent respond more or less aggressively in response? Participants (N = 148) played a competitive reaction time task against a bogus partner, who was either initially non-aggressive, or initially moderately aggressive, and then delivered increasingly loud noise blasts to participants on trials when the participant lost. Both direct (noise blasts delivered to the partner) and indirect aggression (damage to partner's reputation) were assessed. The impact of whether or not participants expected to meet the partner on direct and indirect aggression was also examined. All participants reduced their direct aggression towards an initially non-aggressive partner and a partner they expected to meet. However, for females, the switch from initial non-aggression to later aggression generated a negative evaluation of the partner, exhibited by indirect but not direct aggression.