Comments on J.P. Rushton's table of 'Mongoloid', 'Caucasoid', 'Negroid' rankingsIn numerous publications J.P. Rushton reproduces a table purporting to demonstrate that on a variety of physical, psychological and social measures the ranking of these is consistent with the thesis that 'Mongoloids' are 'K' reproductive strategists and 'Negroids' 'r' strategists ('Caucasoids' being intermediate). The former strategy is characterised by few offspring, high degree of parental care, slower maturation, long life, etc.; the latter by the opposites of these. The sources of the data used to arrive at these ratings are not all cited in the three versions I have available but even a cursory consideration is sufficient to raise numerous prima facie doubts about many of them.
|1 Cranial capacity and brain weight at autopsy show a range between 1448 cc-1408 cc-1334 cc (capacity) 1351g-1336g-1286g (weight) for Mongoloids, Caucasoids and Negroids respectively. They were arrived at from a review of published literature of absolute scores, but it is claimed (Rushton 1990b) that taking allometry into account (i.e. brain/body size ratio) the differences are increased. S.J. Gould (1984), citing the South African palaeontologist P.V. Tobias argues that the determination of average 'racial' brain size is actually so methodologically complicated that nobody has as yet succeeded. Nevertheless let us assume Rushton's figures are correct. As they stand they are impossible to interpret because no standard deviation figures are supplied. Taking the Caucasoid figure as the base, the ranges are 7% (110cc) and 5% (65g). According to Passingham (1982) the modern Homo sapiens brain size ranges from 870 cc-2150 cc (N = 1039) with a mean of 1359.1 (p. 110). Rushton does not provide N's. On the face of it a 110 cc difference in mean scores does not look statistically significant. Given the small degree of difference reported, the variety of methodological problems and the likelihood of unconscious bias among many of those obtaining Rushton's source data these figures cannot be taken seriously. However, even if we take them at face value they cannot really serve the purpose Rushton wishes, namely as indices of intelligence differences. Brain size (actually head size)/IQ score correlations provided in Rushton (1990b) are at most .35 (and this is likely to be deviant), Rushton accepts .3 as the likeliest figure, brain size thus accounts for only 9% of the variance in IQscores at most. Many of the correlations (e.g. on the largest sample, 26,760 US schoolchildren) are under .2 (less than 4% of variance). So how many IQ points does a difference of 7% in brain size signify? |
|2 The mean racial IQs he gives as 107, 100, 85 (M, C, N respectively). As we have seen in the main text however, the meanings of these figures are highly debatable to say the least. If, as argued in the main text, the 'race and IQ' issue is so conceptually muddled as to be meaningless, then these figures can be safely ignored. To include them is to beg the question. |
|3 His 'maturation rate' section includes 'Age of first intercourse', 'Age of first pregnancy' and 'Life-span'-showing the Ms as 'late, late, long', the Ns as 'early, early, short' respectively and Cs as medium throughout. The data sources are not provided. On the |
Questia, a part of Gale, Cengage Learning. www.questia.com
Book title: Race, Racism, and Psychology: Towards a Reflexive History.
Contributors: Graham Richards - Author.
Place of publication: London.
Publication year: 1997.
Page number: 316.
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