“There are two kinds of empathy,” says James Fallon, a neuroscientist at the University of California and author of The Psychopath Inside: A Neuroscientist’s Personal Journey into the Dark Side of the Brain. “Cognitive empathy is the ability to know what other people are feeling, and emotional empathy is the kind where you feel what they’re feeling.”

Autistic people can be very empathetic – they feel other people’s pain – but are less able to recognise the cues we read easily, the smiles and frowns that tell us what someone is thinking. Psychopaths are often the opposite: they know what you’re feeling, but don’t feel it themselves. “This all gives certain psychopaths a great advantage, because they can understand what you’re thinking, it’s just that they don’t care, so they can use you against yourself.”

(Chillingly, psychopaths are particularly adept at detecting vulnerability. A 2008 study that asked participants to remember virtual characters found that those who scored highly for psychopathy had a near perfect recognition for sad, unsuccessful females, but impaired memory for other characters.)

I never thought of psychopaths as the opposite of autistic people before.

Fascinating.