WHERE IS THE SEAT OF EVIL IN THE HUMAN BRAIN?

You don’t have to search very far back in history to find people who were thought to be possessed by evil spirits. As recently as 1944, for example, a self-proclaimed medium, Helen Duncan of Scotland, was prosecuted and convicted under the Witchcraft Act of 1735, though her crime was more likely simple fraud. In 1990, six Roman Catholic priests founded the International Association of Exorcists, and the Church formally approved the group. The practice is part of a long tradition: The Catholic handbook on exorcism was revised in 1999 after having been in force since 1614. Science rarely confuses mental illness with demonic possession, but the Roman Catholic Church remains open to the idea that the latter exists.

Analyzing the results of computed tomography suggests “evil” thoughts arise in the brain as harmless ideas but can gradually be reinforced until they become impulses to act. But which region of the brain harbors evil? It might sound strange, but scientists today are able to monitor evil thoughts as they develop. The impulses appear to arise in the prefrontal cortex, the region brain just behind the forehead.

But what makes us perform evil deeds? Psychologists have coined the term “deindividuation” to describe the phenomenon in which people engage in deviant acts in the belief that they can’t be identified because they are part of a larger group. “This feeling that they are not personally accountable for their behavior is related to a decrease in activity in the ventromedial prefrontal cortex,” explains University College London psychologist Julia Shaw. She says that in practice evil behavior becomes possible whenever any person no longer regards another person as a human being.

The second seat of evil in the brain: the amygdalae, which are involved in the way we experience emotions, such as anger and fear. In response to any fear-inducing stimulus the pertinent information is sent to the amygdalae, which can then send signals that trigger a response such as “ ght-or- ight.” But there are also other processes in the body that can trigger “evil” behavior. For example, studies have shown that a very high percentage of psychopaths have a slow heart rate. According to one theory, the genetic makeup of psychopaths makes it far more difficult for them to experience excitement and fear.

To achieve a thrill at all, a psychopath has to do things a normal person would consider going way too far. Another study has revealed that the ability to exercise self-control is related to blood sugar levels: The lower the levels at any given moment, the greater the likelihood of “evil” behavior. Shaw says when we feel our anger rising, we should check to make sure that we’re actually irate about a situation and not just hungry.