Psychopathy seems to be caused by specific mental deficiencies
WHAT makes people psychopaths is not an idle question. Prisons are packed with them. So, according to some, are boardrooms. The combination of a propensity for impulsive risk-taking with a lack of guilt and shame (the two main characteristics of psychopathy) may lead, according to circumstances, to a criminal career or a business one. That has provoked a debate about whether the phenomenon is an aberration, or whether natural selection favours it, at least when it is rare in a population. The boardroom, after all, is a desirable place to be—and before the invention of prisons, even crime might often have paid.
To shed some light on this question Elsa Ermer and Kent Kiehl of the University of New Mexico, Albuquerque, decided to probe psychopaths’ moral sensibilities and their attitude to risk a little further. Their results do not prove that psychopathy is adaptive, but they do suggest that it depends on specific mechanisms (or, rather, a specific lack of them). Such specificity is often the result of evolution.
Past work has established that psychopaths have normal levels of intelligence (they are only rarely Hannibal Lecter-like geniuses). Nor does their lack of guilt and shame seem to spring from a deficient grasp of right and wrong. Ask a psychopath what he is supposed to do in a particular situation, and he can usually give you what non-psychopaths would regard as the correct answer. It is just that he does not seem bound to act on that knowledge.
Dr Ermer and Dr Kiehl suspected the reason might be that, despite psychopaths’ ability to give the appropriate answer when confronted with a moral problem, they are not arriving at this answer by normal psychological processes. In particular, the two researchers thought that psychopaths might not possess the instinctive grasp of social contracts—the rules that govern obligations—that other people have. To examine this idea, as they report this week in Psychological Science, they used a game called the Wason card test.
Most people understand social contracts intuitively. They do not have to reason them out. The Wason test is a good way of showing this. It poses two logically identical problems, one cast in general terms and the other in terms of a social contract.
For instance, the first presentation might be of four cards, each with a number on one side and a colour on the other. The cards are placed on a table to show 3, 8, red and brown. The rule to be tested is: “If a card shows an even number on one side, then it is red on the other.” Which cards do you need to turn over to tell if the rule has been broken?
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