By Jessica Hamzelou
Manipulative, dishonest and lacking in empathy – the traits that describe a psychopath aren’t particularly pleasant. But the idea that they are also fiendishly clever – as often portrayed in films and TV – isn’t quite true. In fact, in general, psychopaths seem to have below-average intelligence.
You have probably met a psychopath at some point in your life. They make up around 1 per cent of the population, says Brian Boutwell at St Louis University in Missouri. A person is classified as a psychopath if they achieve a certain score on a test of psychopathic traits, which include callousness, impulsiveness, aggression and a sense of grandiosity. “Not all psychopaths will break the law or hurt someone, but the odds of them doing so are higher,” says Boutwell.
Because many psychopaths are charming and manipulative, people have assumed they also have above-average intelligence, says Boutwell. Psychologists term this the “Hannibal Lecter myth”, referring to the fictional serial killer, cannibal and psychiatrist from the book and film The Silence of the Lambs.
To investigate, Boutwell and his colleagues analysed the results of 187 published studies on intelligence and psychopathy. These papers included research on psychopaths in prison as well as those enjoying high-flying careers. They also included a range of measures of intelligence.
Overall, the team found no evidence that psychopaths were more intelligent than people who don’t have psychopathic traits. In fact, the relationship went the other way. The psychopaths, on average, scored significantly lower on intelligence tests. “I think the results will surprise a lot of people,” says Boutwell.
In his experience, DeLisi says psychopaths tend to do poorly at school. “They are very sensation-seeking,” he says. “They don’t like to sit and read books – they end up engaging in substance abuse.” In his own interviews, he has found psychopaths to be rather inarticulate, and to swear a lot. “They talk over you in a brusque, aggressive style,” he says.