On the similarities of American blacks and whites: A reply to J.P. Rushton.
by Zack Cernovsky
Zack Z. Cernovsky studied psychology at the University of Berne and the University of Zurich in Switzerland and subsequently taught various psychology courses for the University of Maryland at U.S. military bases overseas. He is currently director of research and program evaluation at the Addiction Unit of St. Thomas Psychiatric Hospital (a teaching hospital affiliated with the University of Western Ontario) in St. Thomas, Ontario, Canada.
The history of science teaches us that many ambitious racists attempted to manufacture scientific evidence for their beliefs. Sooner or later, theft charlatan style methodology (e.g., the use of skull circumference measurement by Nazi "scientists" during the World War II) and logical inconsistencies resulted in their rejection by the scientific community. A contemporary example of this trend is the work of J. Philippe Rushton. He recently wrote a large number of repetitive articles in which he revived the old-fashioned Nazi method of skull circumference measurement and claimed that Blacks are genetically less intelligent, endowed with smaller brains, oversexed, and more prone to crime and mental disease than Whites. Only some of the numerous methodological flaws in his work are discussed in the present article.
Although Rushton (1988, 1990a, 1991) implied that Blacks are consistently found to have smaller brains than Whites, some of the studies listed in his reviews actually show opposite trends: North American Blacks were superior to American Whites in brain weight (see Tobias, 1970, p. 6:1355 g vs. 1301 g) or were found to have cranial capacities favorably comparable to the average for various samples of Caucasians (see Herskovits, 1930) and number of excess neurons larger than many groups of Caucasoids, for example, the English and the French (see Tobias, 1970, p. 9). In general, skulls from people in countries with poverty and infant malnutrition are smaller regardless of race. This trend is apparent even in Rushton's (1990b) tabularly summary of Herskovits' s review: Caucasoids from Cairo had far smaller crania than North American Negroes (see more details in Cernovsky, 1992). In this respect, Rushton (1990a, 1990b, 1990c) also repeatedly misrepresented findings by Beals, Smith, and Dodd (1984) on cranial capacity. Rushton implied that Beals et al. presented large-scale evidence for racial inferiority of the Blacks with respect to cranial size. De facto, extensive statistical analyses by Beals et al. showed that cranial size varies primarily with climatic zones (e.g., distance from the equator), not race. According to Beals et al., the correlations of brain size to race are spurious: smaller crania are found in warmer climates, irrespective of race.
And, although Rushton misleadingly reported Tobias's (1970) and Herskovits' s (1930) surveys of cranial data as confirming his theory, their data are more consistent with the model presented by Beals et al. As already mentioned, in their reviews, cranial size and number of excess neurons of North American Blacks compared favorably to those of Caucasoids. It is only by pooling their data with data for Negroids from countries in hot climatic zones (notorious for famine and infant malnutrition) that Rushton obtained an illusory support for his postulates.
Rushton's (1988, Table 1) use of brain and cranial size as indicators of intelligence in humans is statistically absurd: Rushton's (1990a) own data showed that brain size and intelligence, in Homo sapiens, are only weakly related (average Pearson r = .18) and the highest correlations reported by Rushton were only .35, implying only 12.3 % of shared variance (see critique by Cernovsky, 1991). In the past decades, even some persons with extremely small cerebral cortices were found by Lorber to have IQs in the superior range (> 120) and performed well in academic settings (Lewin, 1980). Rushton's pseudoscientific writings perpetuate lay public's misconceptions and promote racism.
Rushton (1990a, 1990c, 1991) also misrepresents the evidence for racial differences in brain/body size ratio. For example, Herskovits's (1930) data suggest that there is no consistent Black/ White difference with respect to stature or crania. And, with respect to Rushton's claim about the relationships of the brain/body size ratio to intelligence, this conceptual framework is suitable for some species of animals but not necessarily for the restricted range of data. The comparison of gender differences on three different brain/body indices by Ho, Roessman, Straumfjord, and Monroe (1980) led to inconsistent results (see their tabularly summaries on p. 644). Further empirical data in this field are necessary: Authoritarian statements "about the reality of racial differences," based on conveniently selected trends in the data, do not qualify as a scientific contribution.
Contrary to Rushton's speculations on race and crime, skin color would be a poor predictor of crime rate due to low base rates and very large intragroup variance. His own data (summaries of Interpol statistics, Rushton, 1990c, 1995) can be reinterpreted as showing that relying on race as an indicator of crime leads to 99.8% of false positives (Cernovsky & Litman, 1993a). The average correlations between race and crime are too low and inconsistent to support genetic racial speculations and, in fact, might point to the opposite direction than Rushton postulated (see higher crime rates in Whites than in Blacks in Interpol data analyses, Cernovsky & Litman, 1993b).
To demonstrate that Blacks are less intelligent and, perhaps, to allege that this is genetically given, with only minor environmental modifications, Rushton (1988, 1991) refers not only to his own biased review of brain size studies but also to Jensen's work. Yet, it has been shown that the theories favoring hereditarian over environmentalist explanations tend to be based on poor methodology (see Kamin, 1980) and that Jensen' s estimates of "hereditability" are based on too many assumptions, which hardly could all be met (Taylor, 1980). Some applications of the heritability estimates were shown to have absurd consequences (Flynn, 1987a). Similarly, Jensen's recent claims about racial differences in reaction time are biased and might lack in scientific integrity (Kamin & Grant-Henry, 1987). There is no solid evidence in favor of heritability over environmental influences with respect to the development of intelligence (see a review in Kamin, 1980, and Flynn, 1987a, 1987b).
In a similar vein, some of Rushton's references to scientific literature with respects to racial differences in sexual characteristics turned out to be references to a nonscientific semipornographic book and to an article in the Penthouse Forum (see a review in Weizmann, Wiener, Wiesenthal, & Ziegler, 1991). Rushton's claims that fertility rates are higher in Blacks disharmonize with well-known high figures for some Caucasoids such as North American Hutterites (a group of Swiss- German ancestry, see a review in Weizmann et al., 1990, 1991). Rushton' s claims about racial differences with respect to brain, intelligence, crime, sexuality, and fertility (and also twinning rates; see Lynn, 1989a, 1989b; Weizmann et al., 1991) are based on an extremely biased and inadequate review of literature.
Erroneously relying on data based on hospital admission rates, Rushton (1988) concluded that mental disease is more frequent in Blacks than Whites. Members of the lower socioeconomic class are overrepresented in official hospital admission statistics because the private and more confidential treatment resources are not accessible to them. More adequate epidemiological studies by Robins et al. (1984) based on random sampling show no significant link of lifetime prevalence to race except for simple phobias. There were no significant differences with respect to major psychiatric illness or substance abuse (see a more detailed criticism of Rushton's assumptions in this area in Zuckerman & Brody, 1988).
Rushton (1988, 1991) implies that "racial differences in behavior" are genetic and relatively immutable: He ignores the plasticity of human beings as shown in secular changes and in the intragroup variance (see more detailed criticisms in Weizmann et al., 1990, 1991). The armamentarium of clinical psychologists was shown by a host of empirical investigations to induce desirable behavioral changes in various populations (see, e.g., Turner, Calhoun, & Adams, 1981): Rushton's view of human beings is obsolete.
And, with respect to Rushton's (1988) attempt to apply r/K theory to racial differences, this is a misguided project as shown by criticisms from the ecological and biopsychological perspective (Anderson, 1991; Weizmann et al., 1990, 1991) and as shown by statistical considerations of the devastating effects of restricted range on size of correlation coefficients (rules derived from a wide dimension of measures perform poorly when applied to a minute interval on the scale; see, e.g., McCall, 1980). The r/K dimension is derived from an extremely wide range of species. Its dogmatic application to the drastically reduced variance within contemporary Homo sapiens is statistically naive (for more detailed explanations, see Cernovsky, 1992). It is not even necessary to be a competent statistician to avoid similar errors. If Rushton (1988, 1990a) could heed Jerison's (1973) warning that racial differences in brain size are at most minor and "probably of no significance for intellectual differences," he would not attempt to extend Jerison' s findings across species to subgroups within modern mankind. Instead, Rushton (1991) misleadingly refers to Jerison in a manner that implies an expert support from this famous comparative neuropsychologist, without mentioning their disagreement on the most central issue.
Rushton (1991) claimed that racial differences occur "on more than 50 variables," with Blacks being consistently in a less desirable direction. The present article examined the evidence with respect to the key variables only: The examination exemplifies that his claims are fallacious. Furthermore, long lists, such as Rushton's, tend to shrink when appropriate multivariate methods (e.g., the discriminant equation) are used: These techniques eliminate redundancies and remove nonsignificant variables. And, nota bene, if a scientist would search for a suitable "finding" to lower the social prestige of Blacks and examine 50 variables and suppress evidence favorable to Blacks, he or she might, by chance alone, one day, find one or more variables on which a "significant" trend in the desired direction could be located.
Given all these flaws in Rushton's work on "racial differences," it is obvious that his writings do not meet the usual requirements for a master's thesis in psychology. His knowledge of scientific methodology is definitely below the academic level required for the master's degree.
Finally, Rushton's most recent "scientific" contribution is the claim that women are likely to be less intelligent than men because his tape measurements of men and women in military settings indicated that males have larger heads (Rushton, 1992). Indeed, the racism is often associated with sexism.
In summary, although Rushton's writings and public speeches instill the vision of Blacks as small-brained, oversexed criminals who multiply at a fast rate and are afflicted with mental disease, his views are neither based on a bona fide scientific review of literature nor on contemporary scientific methodology. His dogma of bioevolutionary inferiority of Negroids is not supported by empirical evidence. Acceptance of similar theories should not be based on racist prejudice but on objective standards, that is, conceptual and logical consistency and integrity, quality of methods and data, and an analysis of disconfirmatory trends. Rushton's racial theory does not meet any of these standards.
AUTHOR'S NOTE: This article is based on a paper presented at the 100th annual convention of the American Psychological Association in Washington, DC, August 14-18, 1992. Address correspondence to Zack Z. Cernovsky, Psychology, St. Thomas Psychiatric Hospital, St. Thomas, Ontario, Canada N5P 3V9.
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