Race Differences in Psychopathic Personality: An Evolutionary Analysis
Augusta, Ga.: Washington Summit Publishers, 2019
Herrnstein and Murray’s The Bell Curve (1994) demonstrated that racial differences in rates of social pathology in the United States – including crime, poverty, long-term unemployment, out of wedlock births, and welfare dependency – can in part be explained by differences in average intelligence. They admitted, however, that intelligence could not account for the entire difference; even after controlling for IQ, e.g., American blacks have higher rates of such pathologies than whites:
Some ethnic differences are not washed away by controlling for either intelligence or for any other variables that we examined. We leave those remaining differences unexplained and look forward to learning from our colleagues where the explanations lie.
Prof. Richard Lynn found the challenge irresistible, and proposed in a 2002 paper that different frequencies of psychopathic personality might be the missing explanatory factor. (Correlation between intelligence and psychopathy is negligible to low.)
The term “psychopathic personality” was introduced by the German psychiatrist Emil Kraepelin in 1904, but his conception resembles the condition British physician John Pritchard had called “moral imbecility” in 1835: a deficiency in moral sense not well correlated with any lack of intelligence. American psychiatrist Hervey M. Cleckley’s The Mask of Sanity (1941) remains a classic study of the condition. Among its indicators Cleckley listed
a “general poverty of affect,” defective insight, absence of nervousness and anxiety, lack of remorse or shame, superficial charm, pathological lying, egocentricity, inability to love, failure to establish close or intimate relationships, irresponsibility, impulsive acts, failure to learn from experience, reckless behavior under the influence of alcohol, and a lack of long term goals.
The American Psychiatric Association’s Diagnostic Manual (1994) lists eleven features of psychopathic personality disorder as follows:
(1) inability to sustain consistent work behavior; (2) failure to conform to social norms with respect to lawful behavior; (3) irritability and aggressivity, as indicated by frequent physical fights and assaults; (4) repeated failure to honor financial obligations; (5) failure to plan ahead or impulsivity; (6) no regard for truth, as indicated by repeated lying, use of aliases, or ‘‘conning’’ others; (7) recklessness regarding one’s own or others’ personal safety, as indicated by driving while intoxicated or recurrent speeding; (8) inability to function as a responsible parent; (9) failure to sustain a monogamous relationship for more than one year; (10) lacking remorse; and (11) the presence of conduct disorder in childhood.
The concept of psychopathic personality is not normally applied to children below the age of about 15, but “childhood conduct disorder” has notably similar symptoms, viz., persistent stealing, lying, truancy, running away from home, fighting, bullying, arson, burglary, vandalism, sexual precocity, and cruelty. However, a British study found that only forty percent of boys and thirty-five percent of girls diagnosed with conduct disorder mature into psychopaths. The prevalence of conduct disorder/ psychopathy appears to increase during childhood and decline in adulthood, but there is disagreement as to the age at which it peaks: one study found the highest prevalence at age 17, another at age 12 for boys, and 13 for girls. The condition is somewhere between three and eight times more common in men than women according to various studies (exactness in such matters is elusive).
Two-, three-, and four-factor models have been proposed for psychopathic personality, but the proposed factors always positively correlate, indicating the presence of a general factor. In terms of the five-factor model of personality (consisting of anxiety, introversion-extraversion, conscientiousness, agreeableness, and openness to experience), psychopathic personality correlates most closely with low conscientiousness.
Psychopathic personality disorder is not a discrete condition but the extreme expression of a psychological dimension (altruism-psychopathy) normally distributed through the general population. Lynn explains:
The neurophysiological basis of the altruism-psychopathy dimension is that altruists have an enhanced right amygdala volume and emotional responsiveness to viewing fearful expressions (a measure of empathy), while in psychopaths the right amygdala volume and responsiveness are reduced.
Psychopathic behavior is also more common in those with smaller or damaged prefrontal cortexes, since this region of the brain is crucial for inhibiting behavior. High testosterone levels and low levels of an enzyme called monoamine oxidase A are also associated with psychopathy.
As previously mentioned, Lynn proposed as early as 2002 that racial differences in the prevalence of psychopathic personality might explain some or all of the differences in rates of social pathology not explained by intelligence, noting that psychopathic personality is highest among blacks and Native Americans, next highest in Hispanics, lower in whites, and lowest in East Asians. As he wryly observes: “This theory attracted no attention and has been ignored in texts on this issue.” Now he is back with a guided world tour of the data currently available on the subject.
Some of this data must be treated with caution, being based on interviews with the persons studied—in other words, on self-reporting. Lynn mentions, e.g., two studies that found “no significant differences in the percentages of blacks, Hispanics, and whites with lifetime prevalence of psychopathic personality.” He comments:
The most probable explanation for these anomalous results is that they were obtained from interviewers who asked respondents whether they had ever committed a number of criminal and psychopathic acts. In these interviews it is likely that many respondents did not disclose the full extent of their criminal and psychopathic behavior. This is particularly the case with psychopaths, for whom “no regard for the truth” is a central characteristic. It has been found in two studies that blacks have approximately the same rate of self-reported crime as whites, although records show that that their crime rates are considerably higher.
Lynn begins his review of the evidence with the United States, for which the most extensive information is available. He found only five direct studies of the frequency of professional diagnosis of psychopathic personality by race, four of which measured only with the black-white disparity (all reported higher prevalence among blacks). The best and most recent study (Huang et al., 2006) concerns “personality disorders that includes drug addiction as well as psychopathic disorders”; the prevalence by percentage is therefore higher than it would be for psychopathic personality alone. It does, however, distinguish five groups, finding the highest percentage rate among Native Americans (24.1), followed by blacks (16.6), whites (14.6), Hispanics (14.0), and the lowest among Asians (10.1).
Another important source of information is the Minnesota Multiphasic Personality Inventory, constructed in the late 1930s and still the most widely used instrument for the assessment of abnormal personality. It measures psychopathic personality via a “Psychopathic Deviate Scale” constructed from a set of questions given to both a control group of “normals” and a criterion group of 17–24 year olds who had appeared before the courts and been referred for psychiatric examination because of their “long histories of delinquent type behaviors such as stealing, lying, alcohol abuse, promiscuity, forgery and truancy.” Researchers then selected the fifty-four questions best differentiating the two groups to construct their scale. Subsequent studies have confirmed that the Psychopathic Deviate Scale successfully differentiates delinquents and criminals from non-delinquents and non-criminals.
Lynn found twelve studies measuring racial differences in scores. He presents the racial averages as fractions of a standard deviation above or below the white average defined as zero. The first two studies in the following table were the most extensive, as well as the only ones to distinguish more than three groups.
It can readily be seen that results vary widely for particular groups, especially the racially disparate group known in the US as “Hispanics,” but that apart from that group, the rank order between races is reasonably consistent.
Most of the studies Lynn found measure frequency of particular kinds of behavior characteristic of psychopathy rather than the condition itself. He organizes these under more than two dozen headings, including childhood conduct disorder, school suspension and expulsion, ADHD, failure to honor financial obligations, dishonesty and cheating, crime, extramarital sex, intimate partner violence, recklessness, child maltreatment, self-esteem, drug and substance abuse, difficulty reading the emotions of others, inability to delay gratification, and lack of work motivation and commitment. Again, the rates of incidence found by particular studies vary considerably, but the rank order of racial groups is much clearer:
The pattern of results for the numerous measures summarised in this chapter is that psychopathic personality is greatest in blacks and Native Americans followed by Hispanics, lower in whites, and lowest in Asians, especially in Northeast Asians where data are given for these disaggregated from Southeast Asians.
On some measures, such as rates of rape, assault, intimate partner violence, unemployment, gambling and automotive fatalities, Native Americans score higher than blacks. Since Native Americans are slightly more intelligent than blacks, this is likely explained by a greater frequency of psychopathy among them.
Studies from other parts of the world give us access to data about races poorly represented in the United States. Australian Aborigines appear to have the highest frequency of psychopathic personality in the world. Polynesians, Maoris, and Inuit (Eskimos) all have higher rates of psychotic personality than whites, but lower than blacks or Native Americans. South Asians and North Africans have about the same rate as Europeans, or only slightly higher. Data from Africa, Latin America, and Northeast Asia confirms that levels of psychopathy among their populations are consistent with measurements made in the United States.
Psychopathic personality is significantly heritable and appears to be negatively associated with the gene that produces the enzyme monoamine oxidase A. Scientists have discovered that knocking out this gene in mice makes them very aggressive. Psychopaths have low levels of monoamine oxidase A, and in some cases this is associated with a 2-repeat allele of the MAOA gene. Black males with this allele have “higher psychopathic scores, a significantly greater history of committing acts of serious violence and of being imprisoned.” In persons of all races, the allele is associated with arrests, incarceration and lifetime psychopathic behavior:
Possession of this allele confers an increased risk for young males for shooting and stabbing people. Those with the 2-repeat allele [have] a 0.50 probability of having shot or stabbed someone during the last year, while for those without the 2-repeat allele the probability [is] 0.07. Thus, those with the allele had a 12.9 times greater probability of exhibiting this expression of psychopathic personality.
Studies have found the 2-repeat MAOA allele present in 4.7—5.5% of black men, 0.1—0.5% of white men, and just 0.00067% of Asian men. More recently, another form of the MAOA gene known as the T allele has also been found to correlate with lower than normal levels of monoamine oxidase A and higher incidences of psychopathic behavior. This allele is present in 88% of Africans, 71% of Europeans and 40% of East Asians.
Like all heritable traits, psychopathic personality is subject to evolutionary selection, and Lynn’s book concludes by considering the selective pressures that favor or disfavor it. He hypothesizes
that the cold winters of Eurasia exerted four selection pressures for an enhancement of pro-social personality and against psychopathic personality in the European and especially the Northeast Asian peoples.
1) Stronger male-female bonding based on love evolved as a result of the need for . . . co-operation between parents for provisioning children to survive during the cold winters of Eurasia. Plant and insect foods were not available for much of the year, especially in the winter and spring. During these seasons, women and children needed men to provide them with meat foods that they obtained through hunting. These men would have been the fathers of their children and would have required long term commitment to provision their female mates and children.
2) The second selection pressure exerted by cold winters and springs of Eurasia for an enhancement of pro-social personality would have been an increased capacity to delay gratification by collecting and storing food for future consumption. While plant and insect foods were available throughout the year in sub-Saharan Africa and there was no need to store them, many foods in Eurasia were only available at certain times of the year and these had to be stored for the future. Plant foods were generally only available in the summer and fall, and some potential animal foods were only available at particular times. To take advantage of these opportunities required foresight and co-operation between group members.
3) The third selection pressure of cold winters would have been that as men became increasingly reliant on group hunting they had to develop a greater capacity for co-operation, the maintenance of harmonious social relations and stronger control over aggression towards other men.
4) The fourth selection pressure of cold winters would have been that effective co-operative hunting would have required a reduction of promiscuous sexuality, cheating and other forms of psychopathic behavior that disrupted harmonious and co-operative relations within groups of men.
These are, of course, nearly identical to the pressures responsible for raising the intelligence of the Northern races during recent millennia. Even though there does not seem to be a high correlation between intelligence and absence of psychopathy at the individual level, it is likely the two co-evolved under the same evolutionary pressures. The processes were distinct, however: “The differences in psychopathic personality evolved through a reduction in testosterone, while the differences in intelligence evolved through improvements in neurological processing and increases in brain size.”
Lynn concludes that “differences in intelligence and in psychopathic personality make independent contributions of about the same magnitude to the racial and ethnic differences in the social pathologies documented by Herrnstein and Murray.”