Aggressive action: intentional behavior aimed at causing either physical or psychological harm in a conspecific: hostile aggression: an act of aggression stemming from feelings of anger and aimed only at inflicting pain. Instrumental aggression: aggression that serves as a means to some goal other than causing pain (defensive lineman) Innate instinct/learned social custom: freud postulated that humans have eros and thantos, eros: innate instincts toward life, thantos: innate instincts toward death. Elevated t may be both a cause and an effect of aggressive behavior: animals injected with t are more aggressive, convicts have higher levels of t, being aggressive/competitive/sexual increases t. In humans, patterns of behavior are indefinitely malleable and highly controlled by social norms; thus, cultures vary widely in their degree of aggressiveness. Frustration-aggression theory: frustration, the perception that you are being prevented from obtaining a goal, will result in an aggressive response. In this case, they were more destructive with their toys out of frustration.