Children were matched based on their pre-existing aggressiveness, which was rated by the experimenter and nursery staff on a 5-point scale. The children were divided equally between three groups (aggressive, non-aggressive and control) and half of both experimental groups saw a same or opposite sex role model. The IV was if role model was male or female and aggressive or non-aggressive. The DV was the number of aggressive acts produced by the children in 20 minutes.