Imagine discovering that the way your brain was built showed you had psychopathic tendencies. That's exactly what happened back in 2005, when a neuroscientist named James Fallon was casually leafing through the PET scans of serial killers to figure out which aspects of brain anatomy contribute to psychopathy.

At the time, Fallon had brain scans of all his family members on his desk that he had picked for an unrelated Alzheimer's study. While looking at the scans, he realized that someone in his own clan was a psychopath. It turned out to be himself.

Fallon recognized his scan as "obviously pathological" because of low activity in key parts of the frontal and temporal lobes. Genetic testing showed that he had a number of genes which have been shown to be related to violence, lack of morality, low empathy and other scary psychopath things.

Fallon admits he was not entirely shocked by the discovery because he has always felt manipulative and power-seeking urges within himself, but he noted that they tend to manifest in terms of intellectual competition like trying to win arguments or prove ideas. He also clarified that "I've never killed anybody, or raped anyone."

Since finding out about his brain anatomy, Fallon says he's become more aware of choosing to do the right thing, do good deeds, or take the high road. He also credits his parents' consistent attention and affection during his childhood with allowing him to socialize normally.  This particular case could prove how many factors are involved in determining someone's behavior, including their capability of giving in to their psychopathic tendencies.

[Smithsonian]