The latest issue of Nature has a thought-provoking article on new research trying to understand the psychopathic brain. On most psychological tests, psychopaths appear perfectly normal. Their working memory isn’t impaired, they use language normally, and they don’t have reduced attention spans. In fact, several studies have found that psychopaths have slightly above average IQ’s.
So what causes the psychopath pathology? The problem seems to reside in the emotional brain: psychopaths have tremendous difficulty sympathizing with the emotions of others. When normal people are shown staged videos of strangers being subjected to pain – like a powerful electrical shock – they automatically generate a visceral emotional reaction. Their hands start to sweat and their blood pressure surges. But psychopaths feel nothing. It’s as if they were watching a blank screen. Most people react differently to emotionally charged verbs like kill or rape than to neutral words like sit or walk, but not psychopaths. The words all seem equivalent.
In the Nature article, Robert Hare, the psychologist who led the development of the PCL, or Psychopathy Checklist, speculates on why psychopaths exist:
Hare has used the PCL-SV to estimate that maybe 1 percent [of the general population] are psychopathic, even if they have never committed a crime, according to research presented recently at a meeting on psychopathy research. “Some psychopathic features are not necessarily a bad thing for society – in some professions they may even help,” says Hare. “Too much empathy, for example, on the part of a police office or a politician would interfere with the job.”
Here’s another article on the possible evolutionary origins of psychopathic violence.
Hat Tip: Mind Hacks