by Megan Tan ’19
It is questionable whether psychopaths have a higher or lower IQ than the average human. Previous researchers have investigated the relationship between psychopathy and IQ because there are links to antisocial behavior, violence, and criminal involvement. However, the results have been inconsistent: some studies have demonstrated a negative relationship between the two, whereas others have demonstrated a positive one.
To clarify this discrepancy, Professor Olga Ribera from the University of Cambridge conducted a meta-analysis of 97 studies, with 9010 participants, to research the relationship between psychopathy and intelligence. The participants were limited to male adults who studied written English, as well as a control group consisting of people from the general population. Professor Ribera and her team utilized a psychometric instrument to measure verbal and performance IQ. The means and standard deviations from the studies were used to calculate the effect size and weighted mean effect size. These values were used to give an overall analysis of the relationship between psychopaths and intelligence.
The researchers found a negative correlation between intelligence and psychopathy. Due to the fact that psychopathy could be characterized as successful or unsuccessful, there was a large amount of heterogeneity in their comparisons. Successful psychopaths consisted of people who managed to avoid legal trouble, whereas unsuccessful psychopaths were those who had been involved with the criminal justice system. Professor Ribera revealed that successful psychopaths had a lower negative correlation from the average human intelligence than unsuccessful psychopaths had when compared to the general population. Also, both types of psychopaths showed higher verbal intelligence than working memory and processing speed.
This heterogeneity suggests that psychopathy and intelligence are highly complex and variable traits. More studies, examining the different between successful and unsuccessful psychopaths, as well as utilizing women, are needed to further examine the relationship between psychopathy and intelligence.
- O. Ribera et al., On the relationship between psychopathy and general intelligence: A meta-analytic review. bioRxiv (2017). doi: 10.1101/100693.
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