Psychopathy and intelligence: a second look.

Empirical studies using the PCL-R (Hare, 2003) have shown no intelligence differences between psychopaths and nonpsychopaths. However, Cleckley (1976) argued that psychopaths often show superior intelligence. The purpose of the present study was to test the hypothesis that the correlation between intelligence and severity of criminal development is the opposite in psychopaths than in nonpsychopathic criminals using a sample of 370 men sentenced for violent (nonsexual) crimes. That pattern would provide a way of explaining the discrepancy between Cleckley's view and later empirical work. The results showed that for nonpsychopaths, higher total IQ and particularly verbal intelligence meant a later start in violent crime. For those diagnosed as psychopaths, however, this association was reversed.