The prefrontal cortex...

Oct 4, 2007 08:41 GMT  ·  By

What's paradoxical about the psychopaths is the fact that they seem normal. They apparently behave like normal people, have normal intelligence (in most cases, even above average) and understand the rules of the society. But there is something in their brain that is not impressed by certain things.

Now a team at University of Ulm in Germany and the University of Zurich in Switzerland has detected the brain area that processes the threat of punishment for breaking social rules, a step ahead in understanding the psychopaths. The researchers scanned the brain of subjects to monitor their mental activity while deciding on how to react to a challenge linked to a social norm, in the given case the principle of fairness. One approach meant sanctions for the behavior that broke accepted norms of fairness, and one not involving sanctions.

In the first case, one person was instructed to decide how he will share a certain sum of money with a second person. The recipient knew how much money the first person had retained for himself/herself, and had the option of spending all or only a part of another pot of money which would decrease the first person's income.

In the second approach, the second person just received passively money from the first person, without the power to react in any way.

Brain scans made on the first persons revealed that the prefrontal cortex turned on when they were making decisions susceptible to be punished. Those brain areas were involved in the control of decisions related to fairness and punishing stimuli. When the second person was out of the equation, or replaced by a computer, as the threat of punishment was removed, that brain area displayed much less intense activity.

Subjects with Machiavellian personality traits (like selfishness and opportunism) were also checked. These individuals displayed the strongest reaction to the threat of sanctions, with a higher prefrontal cortex activity, compared to the other people.

This could explain the psychopathic behavior, as people with trauma in the prefrontal cortex present an inability to behave properly, even if they understand social rules.

An impairment in this area "might also underlie certain psychopathological disorders characterized by excessively selfish tendencies and a failure to obey basic social norms," wrote the researchers.

The researchers agree with the criminal justice system treating juveniles, children and young adults in a different manner than adults, as their brain systems are not completely matured.