Race and intelligence: the debate continues

I posted a while back on two duelling essays in Nature on the intensely controversial subject of whether scientists should be permitted to study group differences in cognition. Nature now has a series of correspondence on the topic in its latest issue.

Firstly, there are rebuttals from the authors of the two original essays: Steven Rose argues that the debate is dead and that reviving it serves no purpose, while Ceci and Williams argue (substantially more convincingly, in my opinion) that Rose's declaration of these areas of research as invalid is premature.

Some of the other opinions are predictable: two letters, for instance, simply dismiss the use of IQ as a measure of intelligence. A third letter in a similar vein is more subtle and interesting: Kathryn Holt argues that IQ is an overly simplistic measure, but that more detailed analyses of cognitive differences may prove illuminating:

So, given that we have logical reason to hypothesize about differences
in cognitive abilities, why would we expect to measure these by using a
single number such as IQ, which suggests there must be a hierarchy of
cognitive function? The prediction surely is that each population will
adapt to be better at the particular cognitive tasks that are most
important for survival in its own environment. If this is the case,
then identifying these (potentially adaptive) differences in cognitive
ability, and searching for associations with genetic variants, could
provide fascinating insights into how our brains work.

This makes good sense; if human populations have indeed undergone some level of genetic adaptation to meet differing cognitive demands (which seems entirely possible given what we know about recent human evolution), then investigating group differences may provide useful insights into the molecular architecture of cognition.

One of the most well-respected researchers in the field of group differences in cognition, Jim Flynn, weighs in with a careful and measured response:

As the philosopher John Stuart Mill points out, when
you assert that a topic is not to be debated, you are foreclosing not
some narrow statement of opinion on that topic, but the whole
spiralling universe of discourse that it may inspire. Mill thought that
only someone so self-deluded as to think his own judgement was
infallible could wish to circumscribe an unpredictable future in this
way.

Rose should be very certain he is correct. If
not, and if he converts the rest of us, only Jensen and those of his
persuasion [i.e. advocates of group differences] will publish; and they will win the minds of students
because the rest of us have all adopted a policy of unilateral
disarmament.

Finally, Gerhard Meisenberg appears to advocate the widespread use of genetic engineering (or selective breeding?) should any genetic basis for group differences in cognition be uncovered:

By not investigating the race-intelligence link, we not only perpetuate
ignorance and the prejudice that thrives on ignorance. We also deprive
ourselves of the possibility to tackle the existing inequalities, first
by a judicious development policy and -- should genetic differences
indeed be important -- by eventually changing the allele frequencies of
the offending genes. We should not get stuck in the twentieth-century
assumption that environments are changeable but genes are not. This
will no longer be the case in the twenty-first century. [my emphasis]

This is not a debate that will be resolved any time soon, but it is a credit to Nature that they have permitted such a robust exchange of views on this rather dangerous topic within their pages.

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