More Adrian Raine.
. . . a series of studies using magnetic resonance imaging, which reveals structures and shapes, showed that criminals and people who scored high on tests of antisocial disorders had a smaller than normal orbitofrontal region and amygdala. And the corpus callosum, the communications bridge between the brain’s two hemispheres, was abnormally large.
. . . [Adrian Raine] needed to go back even further and look for a defect that begins before birth and can still be detected in adults. Raine found it in a hole in the head. More precisely, a thin wall of brain tissue that separates a hole—all brains have these spaces—into two. The hole appears during the 12th week of a fetus’s development, and the wall—pushed forward by a normally developing amygdala and other brain areas—divides it by the 20th week. When the wall doesn’t form completely, a condition known by the jawbreaking name of cavum septum pellucidum, it’s usually a sign of abnormal development in the amygdala and other structures. Years later, in adults, the failed wall can be spotted in a brain scan.
In a 2010 paper, Raine and his colleagues compared people with and without the feature on several fronts. The groups were tested for antisocial personality disorder, psychopathy, and aggression. Their records were searched for criminal arrests and convictions. In every single one of those areas, there were a lot more men and women with the wall defect. Here, finally, was evidence tracing criminality back to the womb, before any head-banging could occur.
“I think there’s no longer any question, scientifically, that there’s an association between the brain and criminal behavior. We’re beyond the point of debating that,” says Raine. “Every study can be criticized on methodology. But when you look at the whole, at all the different designs, it’s just hard to deny there is something going on with biology.”