theprovince | This is thought to be the first time that scientists have analyzed the genetic blueprint of a “spree killer”, but it’s far from the first attempt to examine a murderer’s biology. In 1931, the brain of the “Vampire of Dusseldorf”, Peter Kurten, a serial killer, was removed from his corpse after his execution for examination, although no useful conclusions were published. Today, it is displayed in Ripley’s Believe It Or Not! Museum in Wisconsin.
Over the past decade, Dr. Kent Kiehl, a neuroscientist at the University of New Mexico, has visited eight high-security prisons in two US states with a mobile MRI unit, scanning the brains of criminals to see if those defined as psychopaths have different brain structures from “someone who commits a robbery out of poverty”, as Kiehl puts it.
Kiehl’s and others’ research has found that psychopaths’ brains tend to have very low levels of density in the paralimbic system, the area of the brain associated with the processing of emotion, something that may be genetically determined. The result is that psychopaths tend to have impulsive personalities and show little evidence of feeling guilt, remorse or empathy.
In contrast, “spree killers” tend to be extremely depressed, to the point of suffering from a delusional psychosis accompanied by voices or hallucinations, or — as in Lanza’s case — to be young people with physiologically immature brains, who in their state of ultra-sensitivity decide to exact “revenge” on the world for perceived injustices.
THE WARRIOR GENE
Recent years have seen huge advancements in DNA research, with researchers now able to identify specific genes that are linked to anti-social or aggressive behaviour, in particular the MAO-A gene (nicknamed “the warrior gene”), which appears to be hereditary.
A study of Danish twins concluded that a Danish man who has an identical twin with a criminal record is about 50 per cent more likely to have been in prison himself than the average Danish male. Non-identical twins are between 15 and 30 per cent more likely to both have criminal records. Similarly, adoption studies around the world have shown that a child of criminal parents is more likely to become a criminal, even if the adoptive parents are law-abiding.
Irving Gottesman, a psychologist at the University of Virginia who has worked on the Danish twin study, believes the results show that “criminals are not born, but the odds at the moment of birth of becoming one are not even”.
But so controversial are the links between biology and violence that only the bravest scientists have dared tackle it.
“There are many political objections and that means there’s not been enough research into the area,” says Kiehl.
