In summary, young adults who played an aggressive virtual reality game exhibited increased physiological arousal and increases in aggressive thoughts more so than those who observed another person play the game or who simulated virtual reality game movements. Increases in heart rate provided support for the arousal theory, and increases in aggressive thoughts provided support for the social cognitive theory. However, the observational condition did not produce more aggression, as would be predicted by the social cognitive theory. Drive reduction via a decrease in hostile feelings, as would be predicted by the psychoanalytic theory, was not found; nor did hostile feelings increase, as would be predicted by the arousal theory. Hence, the arousal and social cognitive theories received the most support in this study, but no one theory adequately described the impact of virtual reality game play on aggression.