Aggression refers to behavior that is intended to harm another individual. To determine whether or not a behavior is aggressive, we must determine the intent of the perpetrator. The level of intent that underlies an aggressive behavior creates the distinction between emotional or impulsive aggression (which refers to aggression that occurs with only a small amount of forethought or intent) and instrumental or cognitive aggression (which is intentional and planned). Aggression can be nonphysical as well as physical, and nonphysical aggression can be very damaging to its victims.

The ability to be aggressive to others, at least under some circumstances, is part of our fundamental human makeup. Because aggression helps in both our individual survival as well as in the survival of our genes, human beings need to be able to aggress. Under the right situation, if we feel that our self is threatened, almost all of us will aggress.

Aggression is controlled in large part by the area in the core of the brain known as the amygdala. Although the amygdala helps us perceive and respond to danger, and this may lead us to aggress, other parts of the brain—including the prefrontal cortex—help us control and inhibit our aggressive tendencies. Hormones and chemicals such as testosterone, serotonin, and alcohol also relate to our tendencies to aggress.

We are more likely to aggress when we are experiencing negative emotions—a signal that the self is threatened. Frustration occurs when we feel that we are not obtaining the important goals that we have set for ourselves, and frustration increases aggression. Other negative emotions, including pain and the fear of our own death, also increase aggression. These effects are heightened when we are also experiencing arousal. On the other hand, feeling good about ourselves, or feeling good about others, appears to be incompatible with anger and aggression.

Although catharsis, the idea that engaging in less harmful aggressive actions will reduce the tendency to aggress later in a more harmful way, is a theory that is endorsed by many people, there is no evidence that catharsis actually occurs. If we hit a punching bag, pound on a pillow, or scream as loud as we can with the idea of releasing our frustration, the opposite occurs—rather than decreasing aggression, these behaviors in fact increase it. Participating in aggression simply makes us more, not less, aggressive.

As would be expected by principles of social reinforcement, if we are rewarded by being aggressive, we’ll likely aggress again, but if we are punished for our violence, we may subsequently curb our aggression. And we learn aggression by modeling others, an outcome that is particularly problematic for children who grow up in violent families. Although rewarding aggression can increase it, there is, however, a problem with using punishment to reduce aggression: the punishment can be modeled, which can increase the aggressive behaviors that we are trying to stop.

The evidence is clear that the more media violence we view, the more aggressive we are likely to be. If you watch a lot of violence, you are likely to be aggressive. Viewing violence increases the cognitive accessibility of violence, leads us to model that behavior, and desensitizes us to violence. In short, continually viewing violence substantially changes how we think about and respond to the events that occur to us.

Aggression occurs when we feel that we are being threatened by others, and thus personality variables that relate to perceived threat also predict aggression. Gender differences in aggression have been found in virtually every culture that has been studied. These differences in violent aggression are caused by hormones, by evolutionary factors, and also by social learning.

There are cultural differences, both across and within societies, in the observed level of violence. The social norm that condones and even encourages responding to insults with aggression is known as the culture of honor. The culture of honor leads even relatively minor conflicts or disputes to be seen as challenges to one’s social status and reputation and can therefore trigger aggressive responses.

Although biology, social learning, the social situation, and culture are all extremely important, we must keep in mind that none of these factors alone predicts aggression, but that they work together to do so.

Our knowledge about aggression forms a foundation for potentially reducing violence. To prevent the cycle of violence from beginning, we must reduce exposure to violence, help people control their emotions, and work at the societal and government level to create and enforce laws that punish those who are aggressive.

This chapter has reviewed how social psychologists understand aggression. Hopefully, you now have a better understanding of the causes of aggression and may also work harder to try to prevent it—both in yourself and others.