Sunday, September 28, 2003


I guess this post is going to land me in trouble with some people but I have spent my whole life speaking without fear or favour so I am not going to retreat from telling the facts now:

I have just put up another abstract of a recent academic journal article that caused some waves as soon as it was published. The author, Richard Lynn, presents research showing that U.S. minorities tend to score high on the MMPI Pd scale. Wozzat? You say.

The Pd scale is a set of questions that are known to discriminate psychopaths from normals. Psychopaths are people who appear to have no conscience and cannot tell right from wrong. They are very often criminal and often cause severe harm to others. So Lynn has in effect presented evidence that is a psychological counterpart of what we already know -- that U.S. blacks are characterized by an enormously high crime-rate when compared to whites. He shows that psychopathic personalities are much, much more common in the black population -- which makes what we know of black crime eminently understandable. A major cause of black crime would appear to have been uncovered. The cause appears in part to lie in the personalities of (some) blacks themselves.

The major challenges that have been raised to Lynn's findings boil down to asking WHY psychopathy is more common among blacks and challenging whether the Pd scale really does measure psychopathy. The first question is one that cannot be answered with total certainty but, like most personality traits, psychopathy does in general seem to be inborn and genetically inherited. Maybe that is not so among the black population but seeing that blacks and whites are of the same species that would be highly improbable.

The second question is not quite so easily answerable. I have myself had a couple of articles using the Pd scale published in the academic journals and some of my results with it have been less than clearcut. A question I ask about the scale is WHY psychopaths are much more likely to agree with some of the self-descriptions in it than normal people are. I note that the questions in the scale do cover a wide range of maladaptive self-descriptions and this suggests that in institutional situations the scale could be a measure of malingering more than anything else. In non-institutional settings, however, malingering would NOT be a good explanation of the answers given so my conclusion from Lynn's data would be a little more cautious than Lynn's own conclusion. I would conclude that many blacks suffer from a wide range of personality pathologies rather than just psychopathy alone. On the other hand, the congruence of the personality and the crime data do amount to what psychologists would call "convergent validation" for the Pd scale so Lynn's findings could be held to show that doubters such as myself have been proven wrong.

Lynn, R. (2002) Racial and ethnic differences in psychopathic personality. Personality and Individual Differences, 32 (2), 273-316.
Ray, J.J. (1983) Psychopathy, anxiety and malingering. Personality & Individual Differences, 4, 351-353.
Ray, J.J. & Ray, J.A.B. (1982) Some apparent advantages of sub-clinical psychopathy. Journal of Social Psychology, 117, 135-142.


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