Are Murderers Born or Made?

What drives people to kill others? The nature vs. nurture argument that dominates so much of modern psychology seems especially significant when examining the psychological origins of violent murderers.

Dr Cesare Lombroso, often called the father of scientific criminology, hypothesized that serious criminal are a step down the evolutionary ladder, closer to apes in their violent tendencies than all other humans. After years of study, he developed a system to recognized murderers by their elongated features.

Unfortunately, it’s not as simple as Lombroso theorized, although his studies were among the first of many in a scientific struggle to understand the men and women who murder.

As the BBC notes, the search was revolutionized by the invention of brain imaging technologies in the 1980s. British neuroscientist Prof. Adrian Raine was the first to study murderers using brain scans. His years of study and myriad scans of murderer’s minds showed common abnormalities among the killers — reduced activity in the pre-frontal cortex, responsible for controlling emotional impulses, and increased activity in the amygdala, which generates our emotions.

So murderers are more prone to rage and anger but less adept at controlling those emotions. The question still remains: are these tendencies the result of genetics or upbringing?

A possible reason, according to Raine’s studies, is childhood abuse, which might create murderers simply by causing damage to the particularly vulnerable pre-frontal cortex.

“Early physical abuse, amongst other things could have led to the brain damage, which could have led to him committing this violent act,” Raine said.

Not all those who were abused during childhood grow up to become murderers, however. A genetic explanation for violent tendencies has yet to be ruled out, and there is in fact some supporting evidence for the idea.

The BBC reports:

Fifteen years of painstaking research revealed that [the murderers studied] all lacked the same gene.

This gene produces an enzyme called MAOA, which regulates the levels of neurotransmitters involved in impulse control. It turns out that if you lack the MAOA gene or have the low-activity variant you are predisposed to violence. This variant became known as the warrior gene.

An estimated 30% of men possess the warrior gene, but its activation depends upon what happens during one’s childhood. Researcher Jim Fallon possesses many of the genes that should make him predisposed to murder. But instead, he’s a professor drawn to studying the subject partially by his family tree, which is surprisingly lousy with murderers. Fallon isn’t a murderer, and he credits his lack of violent tendencies to his stable and happy upbringing.

“If you’ve the high-risk form of the gene and you were abused early on in life,” Fallon said, “your chances of a life of crime are much higher. If you have the high-risk gene but you weren’t abused, then there really wasn’t much risk. So just a gene by itself, the variant doesn’t really dramatically affect behavior, but under certain environmental conditions there is a big difference.”

So modern study suggests that murderers are both born and made, the separate factors of genetics and environment combining to determine the future of a potential killer. Hopefully, the increased understanding of these factors will allow psychologists and criminologists to spot the warning signs and intervene before it’s too late.

Read more at the source article on BBC.