- 02 May 2017 22:06
#14801899
"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)."
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