Psychopath vs narcissist who would win

James Fallon was almost 60 when he learnt the truth about himself. And it was by accident. In 2005, the US neuroscientist was poring through brain scans for research when he stumbled upon the signs of that infamous rarity in human nature: a psychopath.

They weren’t the first he’d spotted – he’d just finished a study where incarcerated killers were brought in for scans, shackled and under the watch of “a SWAT team on the university roof”. But this psychopathic brain had turned up in the control group of a separate study he was running into Alzheimer’s and schizophrenia. He and his own family were among the healthy volunteers imaged. All the scans were anonymous, so Fallon assumed the psychopath got mixed in by mistake (or perhaps as a practical joke). “When I looked at the brain activity, I knew this was a bad case. I thought this person can’t be just walking around in the world, so I got the lab to check the name.”

When it came back, Fallon made them run it again. He laughed, but it wasn’t a joke, and it wasn’t a mistake. The name on the scan was his.