HonestThinking 18.10.2008. This file contains excerpts from the article James Watson’s most inconvenient truth: Race realism and the moralistic fallacy, by J. Philippe Rushton and Arthur R. Jensen, published by Medical Hypotheses, Volume 71, Issue 5, November 2008, Pages 629-640. The entire article is available from ScienceDirect.




James Watson’s most inconvenient truth: Race realism and the moralistic fallacy




Recent editorials in this journal have defended the right of eminent biologist James Watson to raise the unpopular hypothesis that people of sub-Saharan African descent score lower, on average, than people of European or East Asian descent on tests of general intelligence. As those editorials imply, the scientific evidence is substantial in showing a genetic contribution to these differences. The unjustified ill treatment meted out to Watson therefore requires setting the record straight about the current state of the evidence on intelligence, race, and genetics. In this paper, we summarize our own previous reviews based on 10 categories of evidence: The worldwide distribution of test scores; the g factor of mental ability; heritability differences; brain size differences; trans-racial adoption studies; racial admixture studies; regression-to-the-mean effects; related life history traits; human origins research; and the poverty of predictions from culture-only explanations. The preponderance of evidence demonstrates that in intelligence, brain size, and other life-history variables, East Asians average a higher IQ and larger brain than Europeans who average a higher IQ and larger brain than Africans. Further, these group differences are 50–80% heritable. These are facts, not opinions and science must be governed by data. There is no place for the ‘‘moralistic fallacy’’ that reality must conform to our social, political, or ethical desires.

© 2008 Elsevier Ltd. All rights reserved.



Figure 1. World IQ map of indigenous populations (from Wikipedia).







When one of the greatest biologists of the 20th century, Nobel-Prize winner James Watson, noted that people of African descent average lower on intelligence tests than do Europeans and East Asians, he was excoriated by the mass media and elements of the scientific elite and forced to retire from his position as Chair of the Cold Spring Harbor Laboratory [9,34]. Watson’s treatment was especially egregious given that, in point of scientific fact, more than a century-and-a-half of evidence corroborates his statement. Moreover, supportive new data and analyses appear regularly in mainstream, peer-reviewed journals in the relevant scientific disciplines. Evidence to the contrary is exceedingly weak. Most of the opposition to the genetic hypothesis consists of mere moralizing and worse, the creation of a threatening and coercive atmosphere incompatible with academic freedom, free enquiry, and the civil liberties of a truly democratic society. An enormous gulf separates the politically correct gatekeepers and enforcers from true experts in the behavioral sciences.


Nor is Watson’s case unique. He is but the latest in a long line of academics that have been pilloried and defamed (detailed accounts given in Hunt [20]). The others include Nobel-Prize winner William Shockley, Hans Eysenck, Linda Gottfredson, Richard Lynn, Richard Herrnstein, Charles Murray, Christopher Brand, Glayde Whitney, Helmuth Nyborg, and Tatu Vanhanen. The present writers too have endured their share of attacks. The taboo on race will surely become a major topic of investigation by sociologists of knowledge. There is no parallel to it in the history of science. It is uniquely imposed, mainly through self-censorship, by members of the Western intelligentsia in their own academy – which prides itself on a tradition of academic freedom, open inquiry, and the unfettered discovery, systematization, and pursuit of knowledge and its dissemination to the general public.


Despite the chilling effect described, we (and the others) have persevered in part because of the great importance of the topic, the fascinating data it provides, and the theoretical issues it raises [21]. One of us (JPR) traveled to South Africa to collect new IQ data from highly-selected Black students at the prestigious University of the Witwatersrand in Johannesburg. Seven studies were published based on these data yielding a median IQ of 84 (range 77–103). Assuming that African university students are 1 standard deviation (15 IQ points) above the mean of their population, as university students typically are, a median IQ of 84 is consistent with a (very low) general population mean of 70 [48].


Because many consider the race–IQ hypothesis incendiary, it is essential to thoroughly examine all the relevant data. We did this in our 60-page review, ‘‘Thirty Years of Research on Race Differences in Cognitive Ability,’’ which was published as the lead article in the June 2005 issue of Psychology, Public Policy, and Law, a journal of the American Psychological Association [51]. In the current article we summarize and update those findings (more complete statistical details and references can be found there). Again, the preponderance of evidence argues that it is more probable than not that the genetic contribution to racial group differences in intelligence, brain size and other life-history variables is between 50% and 80%. A good introduction to the issues involved is Bartholomew [1].


On the basis of the 10 research categories listed below, we concluded that the mean 15-point Black–White IQ difference in the US is about 80% heritable and that the 30-point African/non-African IQ difference is about 50% heritable (much of the balance being attributable to cultural and nutritional differences). The evidence demonstrates that: (1) the mean IQ around the world is 106 for East Asians, 100 for Whites, 85 for US Blacks, and 70 for sub-Saharan Africans; (2) race differences are most pronounced on the more gloaded IQ subtests (g being the general factor of mental ability or first principal component; it picks up the ‘‘active ingredient’’ in intelligence tests); (3) race differences are most pronounced on the IQ subtests whose scores show the most heritability; (4) racial differences in brain size parallel the IQ differences; (5) people of mixed-race ancestry average IQ scores intermediate to their two parental populations; (6) trans-racial adoption studies show that Black, mixed-race, and East Asian children raised by White parents have IQs closer to the average of their biological parents than to the White mean; (7) people’s offspring and siblings show regression to their respective racial IQ means; (8) the races differ consistently across 60 related life-history traits; (9) the racial IQ differences agree with the latest accounts of human origins (that is, the out of Africa model); and finally (10) environmental explanations of racial IQ differences have been tested and repeatedly shown to be inadequate.


Black–White IQ differences are found worldwide


National IQs have been reported for 192 countries around the world [30,32]. The results show that the average IQ for East Asians centers around 106; for Whites, about 100; for US Blacks about 85, and for sub-Saharan African Blacks about 70 (Fig. 1). The same rank-order of race differences is found for ‘‘culture-fair’’ tests and reaction-time measures. Reaction-time tasks are so easy that all children can do them in less than one second [25,26]. More intelligent children, measured by conventional IQ tests, perform faster on these tasks. East Asians average faster reaction times than Whites who, in turn, have faster reaction times than Blacks.


Mean IQs differ much less within major population groups (that is, races) than between them. Whites have IQs close to 100 whether they live in Europe, Canada, Australia, New Zealand, or South Africa, whereas Blacks in sub-Saharan Africa have IQs closer to 70 regardless of whether they live in East, West, Central, or Southern Africa – or whether the data were collected in the 1920s or the 2000s. This worldwide pattern contradicts the hypothesis that the low IQ of American Blacks is due to the legacy of slavery, segregation, and ‘‘White racism.’’ Many of the African countries showing a mean IQ of 70, such as Nigeria and Ghana, have been independent for half a century, and the Caribbean island of Haiti for two centuries. However, there has been no documented improvement in cultural achievement or in IQ scores.


Currently, the existence of the 15- to 18-point IQ difference (1.1 standard deviations) between Blacks and Whites in the US is not in itself a matter of empirical dispute. Only its explanation is under discussion. For example, Herrnstein and Murray [18] analyzed data from the 12-year National Longitudinal Survey of Youth. They found that most 17- year-olds with high scores on the Armed Forces Qualification Test (AFQT), regardless of ethnic background, went on to occupational success by their late 20s and early 30s. Those with low scores were more inclined to welfare dependence. The study also found that the average IQ for African Americans was lower than those for Latino, White East Asian, and Jewish Americans (85, 89, 103, 106, and 113, respectively). Similarly, a meta-analytic review by Roth et al. [39] confirmed the 1.1 standard deviation Black–White IQ difference for a total sample of 6,246,729 corporate, military, and higher education testees.


Nor can there be doubt that the average African IQ of 70 is reliable and not due to a ‘‘fluke,’’ or to sampling error, or to the prejudice of investigators. Lynn [30] reviewed over two dozen studies from West, Central, East, and Southern Africa and consistently found an average IQ of 70. For example, in Kenya, Robert Sternberg et al. [61] administered the Colored Progressive Matrices to 85 12- to 15- year-olds who scored an IQ equivalent of 70. In Tanzania, Sternberg et al. [60] gave the Wisconsin Card Sorting Test to 358 11- to 13-year-old; they received a score equivalent to the 5th percentile on American norms (that is, IQ = 75). After training on how to solve problems such as those on the test, the children’s scores improved, but only to about the 9th percentile on American norms (IQ < 80).


It is also generally agreed that because test scores provide the best predictors of educational and economic success, average group differences have important societal outcomes. Further, the Black–White IQ difference shows up before 3 years of age on most standardized test batteries, even after matching on maternal education and other variables. Therefore the race differences are not due to poorer educational opportunities since this has not yet begun to exert an effect. (The East Asian IQ advantage appears by five years of age.)


Because the same differences are found on relatively culture-free tests, and because the tests show similar patterns of internal item consistency and predictive validity for all groups, many psychometricians have concluded that the tests are valid measures of racial differences. In Africa too IQ scores are demonstrably valid. For example, Kendall et al. [28] showed that test scores predicted school grades and job performance equally well for Africans as for non-Africans (i.e., 0.20 to 0.50). Similarly Sternberg et al.’s [61] study of Kenyan 12- to 15-year-old found that IQ scores predicted school grades with a mean r = 0.40. In Rushton et al.’s [53,54] studies of African and non-African university students, scores on one IQ test correlated with scores on another IQ test 3 months earlier (0.60 for Africans; 0.70 for non-Africans) and with end-of-year-exam marks measured 3 months later (0.34 for Africans; 0.28 for non-Africans). The only demonstrated reliable example of bias is the rather obvious one of vocabulary for groups whose first language is not English. Even here, however, language accounts for only about 7 IQ points (out of the 30-point difference).


Brain size differences


Larger brains are more intelligent because they contain more neurons and synapses and can process information more efficiently. Two dozen studies using magnetic resonance imaging (MRI) have shown that brain size is related to IQ differences (within-race) with a correlation of about 0.40. [...] Summarizing the world literature on  race differences in brain size for the three major methods (autopsies, endocranial volume, and head size measures) as well as head measurements corrected for body size, gives results (in cm3): East Asians = 1364; Whites = 1347; and Blacks = 1267. The overall mean for East Asians was 17 cm3 more than that for Whites and 97 cm3 more than for Blacks. Withinrace differences due to differences in method of estimation averaged 31 cm3. Since one cubic inch of brain matter contains millions of brain cells and hundreds of millions of synapses or neural connections, race differences in average brain size may explain their differences in average IQ.



Wanted: More race realism, less moralistic fallacy


The ‘‘naturalistic fallacy,’’ identified by philosopher David Hume (1711–1776), occurs when reasoning jumps from statements about what is to a prescription about what ought to be. An example of the naturalistic fallacy would be approving of all wars if scientific evidence showed warfare was part of human nature. The converse of the naturalistic fallacy is the ‘‘moralistic fallacy’’ – jumping from prescriptions about what ought to be to statements about what is. An example of the moralistic fallacy: Claiming that, because warfare is wrong, it cannot be part of human nature.


The term ‘‘moralistic fallacy’’ was coined by Harvard University microbiologist Bernard Davis [11] in response to demands for ethical guidelines to control the study of what could allegedly become ‘‘dangerous knowledge’’. . .such as the genetic basis of IQ. For well over a generation, the study of the genetic and racial aspects of IQ has given rise to the best examples we have of the moralistic fallacy in action. Happily, under the sheer weight of evidence, there are now signs that this antiintellectual and unscientific prohibition is breaking down, at least in the academic world.


Despite repeated claims to the contrary, there has been no narrowing of the 15- to 18-point average IQ difference between Blacks and Whites (1.1 standard deviations). The differences are as large today as when first measured nearly 100 years ago. Racial group differences, and the associated gaps in living standards, education levels etc., are rooted in factors that are largely heritable, not cultural. For example, Lynn and Vanhanen [32] found that national IQ scores correlate 0.68 with per capita income and rate of economic development. They further show that national IQs cause a number of other social phenomena, such as adult literacy (0.64), enrolment in tertiary education (0.75), life expectancy (0.77), and democratization (0.57). Templer and Arikawa [63] found that per capita income and IQ were related to skin color in international comparisons. Subsequently, Templer [64] found that national IQs and skin predict infant mortality, fertility, and even HIV/AIDS rates.


IQ differences are attributable more to differences in brain size than to social, economic, or political factors. There is little or no value in denying reality. Improving opportunities and removing arbitrary barriers is a worthy ethical goal. Equal opportunity is laudable. But we must realize that it will result in equitable, though unequal outcomes.


Expanding on the application of his ‘‘default hypothesis’’ that Black–White differences are based on aggregated individual differences, themselves based on both genetic and environmental contributions, Jensen [26] proposed ‘‘two laws of individual differences’’ – (1) individual differences in learning and performance increase as task complexity increases, and (2) individual differences in performance increase with practice and experience (unless there is a low ceiling on proficiency). Consequently, the more we remove environmental barriers and improve everybody’s intellectual performance, the greater will be the relative influence of genetic factors (because the environmental variance is being removed). However, this means that equal opportunity will result in unequal outcomes, within-families, between-families, and between population groups. The fact that we have learned to live with the first, and to a lesser degree the second, offers some hope we can learn to do so for the third.



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