We talk about 'psychopaths' like they're a different species. Identifiable. Separate. The cold ones, the ones without empathy (actually, they can have excellent cognitive empathy), the ones who are fundamentally not like us.

But most people who score high on psychopathic personality traits are not in prison. They are in boardrooms, operating theatres, and on the campaign trail. Some of them are extremely successful. Some of them are considered admirable.

The traits we pathologise in a person who commits crime, we reward in a person who has a swanky office. There is a lot to be learned by studying the latter group.