A serial killer is someone who murders three or more people during separate events with a "cool off" cycle in between. Serial killers go through a cycle in which they kill, once they have killed, they feel a temporary relief until the next cycle arises. Psychologists believe that serial killers may have experienced some type of abuse as children; neglect, physical abuse, sexual abuse, or some other type of maltreatment. There is usually some type of motivation that accompanies the murder, it could vary from obtaining money, thrill experience, or a sense of power. .
There are many parts of the brain that could be responsible for triggering this kind of action. Psychologists have researched many different parts of the brain and the associations, but have not been able to identify the exact cause. Many believe that it could be injury to the brain from an accident, being born that way, abuse, or an imbalance somewhere in the brain. There are many parts of the brain that could be associated in some way, but there seems to be a drastic difference in the Orbital Cortex of a normal person and a not so normal person.
The Orbital Cortex is responsible for many functions. It is involved in critical human functions, control of the mood, drive, responsibility, and social ability. All of these things are crucial when defining someones personality. It is also believed that the Orbital Cortex plays a role in other functions of the brain, such as, memory and decision making which are considered basic components of social and emotional behaviors. Psychologists believe that people with low activity in that portion of the brain are "free wheeling types or sociopaths.".
There has been very extensive research put into the brain of a serial killer, with significant differences identified in the brain of a normal person and a serial killer. The difference in the serial killers was the smaller, or nonexistent orbital cortex.