Is violent behavior in humans caused by innate or environmental factors? The answer has important implications in the efforts to combat the rising levels of aggressive behavior in today’s society. If violent behavior is innate, there may be little we can do to reduce aggression levels; on the other hand, if it is caused by external factors, then we might be able to reduce aggression by changing the environment.
It is a widespread assumption that biological factors are a major influence on violent behavior, specifically, that testosterone causes aggression. There have been many empirical studies supporting this theory. However, many of them are animal studies, so we need to be careful about generalizing the results to humans. Of course, there are also studies on testosterone involving humans. One example is a correlation involving American war veterans: the higher their testosterone levels, the more likely they were to have a violent history. However, since this was a correlation, we can’t really establish a cause-and-effect relationship. There was also a correlational study which seemed to show that men in prison for aggressive crimes were more likely to have an extra Y chromosome. For a while this provided support for the opinion that we should identify potential criminals’ based on their genes and put them under observation. Naturally, there was much debate around the matter until the study of a control group showed that non-aggressive males had the same ratio of XYY chromosomes as aggressive males. Thus, the theory that the extra Y chromosome increases violent behavior was disproved.
On the other hand, Freudian theory suggests that aggression is innate. Freud theorized that human behavior is largely driven by an unconscious psychological construct called the Id. The Id has an innate desire to be aggressive. Frued further theorized that we have a death instinct called Thanatos, which drives us to destroy others and ultimately ourselves. However, readers should bear in mind that this concept is not widely accepted by psychologists in general. It is also implied that violent behavior might result from ego defense mechanisms, such as displacement, where you displace your feelings of aggression onto a non-threatening target. Freud suggested catharsis as a way of safely getting rid of aggressive wishes. For example, by watching a violent program you indulge in your aggressive desires and therefore you don’t feel the need to exhibit violent behavior yourself. However, as a whole, there is no empirical support for Freudian explanations of aggression; in fact, there are numerous studies which show that the more you watch violent behavior, the more likely you will be to behave aggressively yourself.
Those studies were mostly conducted in order to find support for Bandura’s social learning theory, which states that people learn by imitating the behavior of other people they see. Studies range from Bandura’s infamous Bobo doll experiment, where children who were exposed to aggression against a Bobo doll imitated the aggressive behavior, to correlations, such as Eron’s study which showed that boys who viewed more aggression at age 8 were more likely to exhibit violent behavior at age 30. There was also a natural observation of an isolated island community; aggression levels rose a year after television (which contained violent programs) was introduced into the island. These studies provide a strong basis for the idea that the exposure of people to violence in media such as television, movies, and games will lead to an increase in aggression, and consequently, the idea that violent media should be censored to prevent people, especially children and teenagers, from imitating aggressive behavior.
A variation on Bandura’s Bobo doll experiment showed that the participants were more likely to behave aggressively when violent behavior was seen to be rewarded. Bandura termed this vicarious reinforcement. The concept of reinforcement came from Skinner’s theory of operant conditioning, which can also be used to explain aggression. If people are reinforced for behaving aggressively, for example, if teenagers gain approval from peers for violent behavior, they are more likely to exhibit aggression in the future. Another of Skinner’s theories, classical conditioning, states that basically, if certain stimuli are associated consistently with violent behavior, people will naturally react aggressively when exposed to those stimuli. A experiment showed that when people were asked to deliver electric shocks to a confederate, they delivered more shocks when they were exposed to a gun instead of neutral stimuli like badminton rackets.
Another theory supporting the concept that violent behaviour is caused by environmental factors is the frustration-aggression hypothesis, which states which frustration will always lead to aggression. Again, there is some empirical support for this theory. A correlation showed that, in America, when cotton prices dropped, thus increasing the frustration of people, the number of black lynchings increased. There was also an experiment where high scorers on an anti-Semitic scale were asked to make up stories about people shown in pictures, some of which were Jewish. When the experimenters frustrated the participants by insulting them, the stories the participants made about the Jewish people were more likely to be violent.
Judging from the great variety of research studies and theories reviewed above, it is likely that there are a multitude of factors influencing aggression. Psychologists today normally take an interactionist position on the nature-nurture debate on aggression; we accept that both innate and environmental factors, combined, give rise to violent behavior. However, it is also possible that innate factors might have more influence than environmental factors, or vice versa. Nevertheless, since we have only power to modify the environment, it might be more productive to focus research efforts on identifying environmental factors that we can change in order to reduce levels of violent behavior in society.
