A reader sent me this discussion of psychopathy as an adaptation:
A disorder, by definition, is the failure of some physical or mental feature to do its natural, evolved function.What is the new scientific evidence that suggests that psychopathy is an adaptation and not a disorder?
Research on psychopaths shows big differences in the ways they act (impulsive especially in the presence of rewards), process information (unaffected by emotionally powerful information), and learn from experience (resistant to punishment). These have been thought of as defects, but it is just as possible they are adaptations that underlie a life long aggressive, cheating, and manipulating strategy.
[O]ther researchers have discovered that violent people have high rates of particular types of medical problems in their histories -- obstetrical problems (toxaemia, Rh factor, maternal substance abuse, etc.), and perinatal difficulties (e.g., prematurity, low birth weight, severe fetal distress). Such problems are also associated with schizophrenia. These findings suggest that violence can be the result of problems in very early physical development, and that schizophrenia is a true disorder of neurological development. (It is interesting that people with schizophrenia are not especially violent, however.)Interestingly, the author of this article (Grant Harris) was one of the researchers of the famed failed Social Therapy Unit at Oak Ridge from the 1960s-70s, through which we learned that having psychopaths sit around and talk about their feelings actually seems to make them worse, not better. Even then Dr. Harris acknowledged that psychopath doesn't seem much like your typical disorder: "Unlike virtually every other mental disorder, however, where the existence of the problem is inferred from difficulties experienced by the patient, psychopathy is a disorder whose negative effects accrue more to those who come into contact with the psychopath than to the patient him or herself."
What does our adaptation theory say should be found in the prevalence of these medical problems among psychopaths? Because the theory says that psychopathy is not a disorder of neurological development, psychopaths should have fewer of these problems than other violent offenders. And that is what we found. If psychopathy were an extreme disorder (and knowing that these problems are associated with violence), one would predict that psychopaths would have high rates of these problems, but we found the opposite.
We also tested our theory with another measure of developmental stability -- fluctuating bilateral asymmetry. That is a polysyllabic way of saying, the degree to which the left side of the body is exactly the same size as the right side. In all species, the two sides of the body are genetically programmed to be the same size -- symmetrical. The amount of difference between the two sides, asymmetry, is a measure of the instability in a person's development. Again, violent individuals have been reported to be asymmetrical as have persons with schizophrenia. What about psychopaths? Our research showed that violent offenders who were also psychopaths were more symmetrical than those who were not psychopaths.
Again, although psychopaths are the most dangerous offenders, they do not have signs that their neurological development has been disrupted. From a medical point of view, they appear to have had healthy development compared to persons with schizophrenia or mental retardation.
Of course, our theory definitely says that the nervous systems of psychopaths must be different somehow. But that difference should not, according to the theory, look like damage. In fact, attempts by other researchers to find signs of damage in psychopaths using neuropsychological tests or fancy imaging methods (CT, PET, MRI scans, etc.) have not panned out.
So far at least, it does not look as though psychopaths have damaged brains, even though it does appear that their brains are different.