The video on the right is the third part (out of four) of the documentary, which I chose because I think it contains the most useful information.
If you don't feel like watching it right now; here's a summary: Dr. Robert Hare, famous for his analyses of psychopathic serial killers, discovered emotional differences that could later be seen using PET scans. A certain Prof. James Fallon got involved in this area of research when he was asked to analyse a variety of brain scans. Without knowing the different categories, he divided the scans into groups - one of which he called 'abnormal' brain scans. And voilĂ - those were the psychopaths (which Fallon was told only then).
The left brain scan is 'normal', the right psychopathic. |
The pattern was relatively simple: the
psychopathic brain scan showed significant damage to the orbital cortex (located behind the eyes, the area that is actively red in the normal scan) and the temporal lobe. Both of these are related to emotion - for example through the amygdala - and, more significantly, impulses.
The story goes on, though, and we find out one more thing that supports the Nature side of the debate: in 1993, the search for genetic factors that influence criminality turned up a certain gene responsible for the production of monoamine oxidase A. This, also known as MAOA, is related to a variety of unpleasant things both when it is missing and when it is slightly altered; things like antisocial conduct disorder and - big surprise there - violent behaviour.
The whole thing becomes quite dramatic then, as Prof. Fallon find out he himself carries that gene abnormality. However, he obviously is a psychologist, not a psychopathic murderer. We see an interview of his own son saying that there was "always something off" about his father.
So don't think Nature won this round! Because there is one thing Fallon tells us: that he had a great childhood in a loving environment. Which means that it's not enough to be genetically predisposed to violence if nothing ever triggers it.
Since this is already becoming too much of a rant I'll talk about how this relates to fictional villains in my next post. Stay tuned! (Yeah, right...)