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.
But Boutwell wasn’t convinced. “Psychopaths are impulsive, have run-ins with the law and often get themselves hurt,” he says. “That led me to think they’re not overly intelligent.”
Not so smart
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.
Matt DeLisi at Iowa State University hopes that the findings will help put the Hannibal Lecter myth to rest. “The character promulgated the notion that psychopaths were highly intelligent, and there were real offenders that embodied this, like Ted Bundy,” says DeLisi. “But I have interviewed thousands of offenders, some of which are very psychopathic, and I have found that the opposite is true.”
Towards a treatment
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.
Boutwell hopes that his research will add to a growing understanding of how psychopathy works, and whether we might be able to treat it. As things stand, psychopaths tend to be considered “untreatable”, and many of those who have been incarcerated end up reoffending. “Psychopathy isn’t amenable to psychotherapies,” says Boutwell. “As we better understand psychopathy, we should be better able to develop treatment and rehabilitation for psychopaths.”
Changing the way people perceive psychopaths might also affect the way they are treated by the criminal justice system. “If they have low intelligence, you could say that they are likely to offend again, or you could say that if they have cognitive difficulties, a lengthier prison sentence is not going to help them,” says Boutwell. “You could make the argument in either direction.”