There are no simple explanations for aggression and violence, and psychologists are struggling to understand violence among youth. One hypothesis of aggression is the frustration-aggression hypothesis. According to this hypothesis, aggression and violence can result from being prevented from reaching some desired goal. For example, some news reports have claimed that a recent shooting rampage resulted when one young man was jilted by his girlfriend. Athletes scream obscenities at officials ruling foul behavior.
Shoppers fight over the last remaining item at a sale.
But frustration doesn't have to lead to aggression. Some people seem more prone to aggression than others. Aggression also runs in families. Researchers, reasoning from animal models of territorial aggression, aggression within social groups, and selective breeding for aggressive traits, argue that genetics contributes to aggression and violence. Another hypothesis is the observational learning hypothesis.