In the United States today there is considerable legitimate concern about the problem of violence and aggressive behavior. Many people believe that America is an armed camp. With 67 million handguns in circulation, every year some 640,000 people are confronted by a criminal with a handgun, and this violence leads to more violence as fear of guns sells more guns in an endless feedback loop. All too often casualties are children. Each day 13 youngsters are killed by guns and 30 others are wounded: in 1991 alone, 5,336 died. Even in schools, tens of thousands of guns are carried to class every day.
Others believe violence will not be cured by limiting handguns, although this is a start. They state that society must find the causes of violent and aggressive behavior. Accordingly, this viewpoint has given rise to many theories about the causes of violence and aggressive behavior. Recent studies have discovered that aggression is not a unitary concept. There are different kinds of aggression. Some of the experimental evidence supports the idea that there are organized neural systems in the brain for the various kinds of aggression. When these systems are active in the presence of particular stimuli, the organism has an increased tendency to behave aggressively. Thus aggressive behavior is stimulus-bound and dependent on the functional integrity of the relevant neural systems. Although the exact mechanism cannot yet be specified, the sensitivity of the neural systems for aggression may be raised or lowered by specific blood components, particularly from the endocrine system. If some hormonal influences occur early in the life of the organism, the effects on the neural systems may be permanent.
Learning has an important influence on aggressive behavior. Aggressive behavior that is rewarded tends to be repeated, and that which is punished tends to be inhibited--at least according to prevailing theories. Furthermore...