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Race, IQ and James Watson

A couple of months ago, James Watson – who, together with Francis Crick, was awarded the Nobel Prize for deciphering the double helix structure of DNA – claimed that black people are less intelligent that white  He invoked the authority of science to make his claim. Of course, if the claim had simply been that on average (say) African-Americans had lower scores on IQ tests than White Americans (and that this difference was reflected in educational achievement and other socioeconomic indicators), Watson would simply have been citing facts. The controversial part of Watson’s claim was that the difference was rooted in the genes of blacks and whites and therefore fixed. The first part of the claim is (probably) false – the genetic differences between blacks and white are largely skin deep. But even were it true it would be irrelevant to the real question. Watson calls himself ‘gloomy about the prospect of Africa’, because he thinks that ‘genetic’ means ‘fixed’. But ‘genetic’ does not mean ‘fixed’; the fact that the differences between two individuals are explained by differences in their genes has no implications whatsoever about how hard or easy it is to eliminate the difference. Differences rooted in environmental factors (to the –limited – extent to which it even makes sense to separate environmental factors from genetic) may be easier to eliminate than those rooted in the genes, or they may be harder. Genes work like sets of switches, under the control of other genes and environmental factors. These sets can be configured differently to produce very different results; changing a few triggers thereby produces very different products from much the same genes. In any case, the evidence strongly suggests that this particular IQ deficit is remediable.

Now the story has taken an ironic twist. An Icelandic company called deCODE Genetics has analyzed a sample of Watson’s DNA and found that he likely had recent African ancestry.

The irony is delicious, but unfortunately the science doesn’t stack up. In principle, it is possible to make this kind of finding, but we don’t have the data available at the moment. We can trace ancestry through mitochondrial DNA, which is inherited matrilinearly and almost always unchanged. Doing that (or utilizing the Y-chromosome, inherited partilinerarly), we can establish an individual’s haplogroup. But there is no haplogroup that corresponds to the designation ‘African’, which is a geopolitical designation, not a genetic one. Even if Watson has mitochondrial DNA or a Y-chromosome originating from one of the haplogroups associated with Africa, we would know nothing about how recent his African ancestry was. The deCODE analysis does not seem to use haplogroup data; instead it compares DNA to known samples, gene-by-gene. The problem with this is that given how crude our available data, this kind of data is meaningless: we simply lack enough comparison DNA to get to the fine-grained level of analysis we need to make these claims.

We should dismiss Watson’s claims because they are bad science. Knowing a lot about the structure of DNA does not give you insight into how it works in constructing individual organisms. Human differences and similarities need to be understand at multiple levels, not by focusing on genes.

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1 Comment on this post

  1. One interesting aspect of the debate following Watson’s comments (which referred to Africa) was that it concentrated almost entirely on IQ gaps between racial groups within rich countries, rather than the gaps between rich countries and Africa.

    But in fact we have far stronger, indeed overwhelming, evidence that most of the gap between the United States and sub-Saharan African states (typically ~2 standard deviations) is environmental than we do for the same claim with respect to racial gaps in rich countries (a single standard deviation gap between whites and African-Americans in the USA).

    Even if only a third to half of the black-white gap in the US today is environmental, sub-Saharan African IQ could be improved 20 points or more through environmental changes (starting with micronutrient fortification, prevention of childhood infections that interfere with brain development, schooling, etc), bringing African countries to par with relatively prosperous places such as Mexico and Brazil. UNICEF uses such rhetoric in its efforts to promote iodine fortification (severe iodine deficiency can lower intelligence by a standard deviation), but in general the topic seems neglected as a research area.

    Further, we should remember that environmental developments may improve the African situation without closing a gap, e.g. nootropic drugs might help alleviate African troubles and also lift all boats.

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