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March 02, 2005

Race and Psychopathology

Back in 2002, Richard Lynn published an investigation of racial differences in psychopathology. Arguing mostly from the Minnesota Multiphasic Personality Inventory (MMPI/MMPI-2) Psychopathic Deviate scale and a host of social factors like school suspensions, crime rate, long-term monogamous relationships, extramarital sex and "moral understanding," Lynn concluded the trait's distribution was in line with what Steve Sailer calls "Rushton's Rule": psychopathology is most prevalent among individuals of African descent, least among Asians, and Caucasians intermediate.

Not surprisingly, Lynn's paper received a lot of criticism. Zuckerman (2003) argued Lynn did not clearly draw a distinction between the psychopathic personality and criminality:

Although criminal history is often used as a surrogate for APD, actual diagnosis must inquire beyond the mere history of arrests and convictions. Otherwise there is no point in the distinction.

This conceptual confusion leads Lynn to neglect statistics that potentially conflict with his view -- namely -- the incidence of diagnosed Antisocial Personality Disorder. The largest such study of this kind, Robins and Regier (1991), failed to find any significant racial difference.

In October's issue of Law and Human Behavior, the authors of a new study go one step further and conduct a meta-analysis of the pertinent literature. 21 studies, all relying on Hare's widely used Revised Psychopathy Checklist (PCL-R) or its derivatives, were included.

Their results are interesting, and worth quoting at length.

Our chief finding is that there is little evidence that Blacks are more psychopathic than Whites in the aggregate. The strongest foundation for an argument that ethnic groups differ in psychopathy would be a finding of large and reliable group differences on the interpersonal and affective characteristics of Factor 1, given the relative nonspecificity of the behavioral features of Factor 2 (see Lilienfeld, 1994; Skeem & Mulvey, 2001). The results of this study directly counter this argument. On the basis of homogeneous effect sizes from studies of 8,890 individuals, we found that Blacks are no more “emotionally detached” (Patrick, Bradley, & Lang, 1993) than Whites. When considered in conjunction with the results of Cooke et al. (2001), who found minimal differences in PCL-R factor structure and in the meaning of Total scores between these ethnic groups, there seems little reason to believe that there are significant ethnic differences in “core psychopathy” in this population.

However,

This may well be true of psychopathy, more broadly construed. Although statistically significant, the size of the effect for PCL-R Total scores (d = .11) is about “half as small as small” (Kenny, 1999, p. 6), according to Cohen’s (1988) interpretive guidelines. On the 40-point PCL-R, Blacks obtained scores that were a weighted average of 0.7 points higher than Whites. To place the absolute magnitude of this difference into a practical context (American Psychological Association, Board of Scientific Affairs, 1999), it is less than one-fourth the size of the standard error of measurement (SEM) for the PCL-R. The SEM for PCL-R total scores is 3.1 points, meaning that “if 100 trained raters assessed the same subject (sic) at the same time, about 68% of the scores would fall within +/− [3.1 points] of the subject’s (sic) obtained Total score . . . ” (Hare, 1991, p. 36).

In other words, "blacks exceeded Whites by an average of less than one point on the PCL-R".

References

Lynn, R. 2002. Racial and ethnic differences in psychopathic personality. Personality and Individual Differences 32: 273-316

Skeem, J.L. et al. 2004. Are there ethnic differences in levels of psychopathy?
A meta-analysis. Law and Human Behavior 28: 505-527.

Zuckerman, M. 2003. Are there racial and ethnic differences in psychopathic personality? A critique of Lynn's (2002) racial and ethnic differences in psychopathic personality. Personality and Individual Differences 35: 1463-1469.

Posted by God Fearing Atheist at 09:38 PM