Many psychoanalysts have argued against these theories, which see aggression as a primary drive, offering the possibility that aggression may be a reaction to frustration of primary needs. In the late 1930s, John Dollard argued that any sort of frustration inevitably led to an aggressive response. More recently, Albert Bandura has performed studies that indicated that aggression is a learned behavior. Using children in his studies, Bandura demonstrated that, by watching another person act aggressively and obtain desirable rewards or by learning through personal experience that such behavior yields rewards, aggression can be learned. A number of psychologists contend that children and adolescents are vulnerable to media portrayals of violence, particularly in film and television.
Popular media tends to depict violence as relatively common, and generally effective.
3 Recent research on the biological basis of aggression has sought to show that genetic factors may be responsible for aggressive behavior. In the 1970s it was suggested that men who were born with an extra Y chromosome were likely to display more episodes of aggressive behavior than men who were not born with this extra chromosome. Still, conclusive proof has yet to be found for a genetic theory of aggression. Each theory may be accurate in part, since aggression is believed to have a number of determining factors. The Columbia Encyclopedia, Sixth Edition.