I've met many psychopaths over the years, and many aspects of this TV show ring true. In the first series, we discover that Dexter Morgan's violent tendencies first came out in childhood, when he would murder neighbourhood pets. Cruelty to animals is indeed one of the first signs of a psychopath: it springs from their lack of empathy. Also, just like most psychopaths, Dexter is incredibly charming and a master of concealment. Think of all those serial killers who manage to kill over and over, undetected.

Not all psychopaths are as intelligent as Dexter, though. A psychopath with violent tendencies, a poor upbringing and limited education might end up as a thug or an enforcer for a criminal gang. An intelligent, violent one with a good education might end up as a top CEO, a lawyer, or a serial killer.

There are a few anomalies, however. The voiceover that runs through each episode, with Dexter analysing his actions, strikes me as unlikely. Most psychopaths aren't interested in applying that degree of self-knowledge. And he seems very attached to his family, especially his sister, which is unusual. That said, some psychopaths are definitely able to compartmentalise their violent tendencies: the Kray twins were very attached to their mother. In fact, some interesting research from the Netherlands has indicated that psychopathic criminals may be able to access a sort of "empathy switch", enabling them to feel for some people, and not at all for others.

I met Michael C Hall, the actor who plays Dexter, during a book tour in America. I can safely say there's nothing psychopathic about him. But I did ask him which aspects of Dexter he'd most like to carry into his own personality. "His coolness under pressure," he said. That coolness is one of the reasons why we're so fascinated by psychopaths: unlike the rest of us, they operate with complete impunity; they just don't care what people think. In this age of 24/7 surveillance, we find that sense of freedom hugely appealing – even if we're sure we'd never be violent ourselves.

• Dexter is on Fox at 9pm on Sundays. Professor Dutton is a research psychologist at the University of Oxford and the author of The Wisdom of Psychopaths.