Letter from Francis Crick to John T. Edsall, Fogarty International Center
In his letter Crick called for "constructive approaches" to research on the interaction of heredity and environment
in the formation of intelligence, an issue brought to the forefront of public debate in the late 1960s by the writings of
William Shockley and Arthur Jensen. In particular, Crick called for more research on identical twins separated at birth.
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1971-03-29 (March 29, 1971)
Edsall, John T.
Fogarty International Center
Original Repository: Wellcome Library for the History and Understanding of Medicine. Francis Harry Compton Crick Papers
I was very pleased to receive your letter of March 5, especially as it strikes a rather different note from your letter to
the Academy. I agree with you that Shockley arouses a maximum of antagonism, but this I think is due to his manner rather
than his matter. In fact, Jensen pointed out to me that while he and Shockley say much the same thing, Shockley always manages
to upset people!
I agree with you about Jensen's paper. I'm afraid none of us is immune from bias on this subject, but his seems quite
small. I do not agree with you about Lewontin. He makes a useful point - that the difference between two populations may
still be due to environment, even though within both populations the variance may be largely genetic but it is one that most
people in the field are aware of. Otherwise his tone is to be deplored, although it shows how strongly people feel about
As to your point about the I.Q. results on American Indians being mainly due to their cultural tradition, this may be so,
but personally I doubt it. How do you explain the relatively poor I.Q. performance of the children of middle-class American
I.Q. tests do seem to me to be useful, in spite of their obvious limitations, if only because people's social aspirations
are highly correlated with I.Q. That is, if the population as a whole is asked to rank occupations (most people would rank
doctors higher than dustmen), then this ranking is almost perfectly correlated with the average I.Q. of the people in the
occupational groups (i.e. doctors have, on average, a higher I.Q. than dustmen). Naturally for comparing differences between
two cultural groups an I.Q. test should be, as far as possible, culture-free.
I have not seen the report of the Academy Committee headed by Kingsley Davis, but I look forward to reading it in due course.
What I miss most is constructive approaches to this problem. Can the "environmentalists" set up in an experiment
an environment which will make the I.Q. difference disappear? If they can't do that, then the hope of doing anything
on a large scale in a social context is remote. Can the "geneticists" produce an experimental test which will show
definitively that more than half the difference is genetic? Incidentally, a reasonable design for such an experiment exists,
but nobody (except possibly Shockley) will fund it, mainly due, I suspect, to the attitude of people like yourself and your
colleagues, and of Bodmer and Cavalli-Storza.
I still feel that if you and your colleagues do not agree with Jensen's tentative conclusions, you would do a useful job
by refuting his argument point by point. Also, I would like to see your plans for research in this field, so one can see
how long a period is likely to be involved.
May I make a general suggestion, which I put forward in a lecture a year or so ago, which might be drawn to the Academy's
attention? A most powerful research tool is the study of identical twins separated at birth. Jensen has recently looked
into all the cases for which I.Q. data are available and finds there are only about 125 of them. Why should not a Twins Institute
be formed? This would encourage people who have twins to let one of them be adopted by another family. Both the rate of production
of twins and the rate of adoption are sufficiently high that worthwhile numbers would soon accumulate. It is essential to
keep track of such cases, and examine them periodically, and this would be the job of the Institute. Let me emphasize that
there would be no compulsion for people who have twins to let one (or both) be adopted, though they might be encouraged by
a modest subsidy given in return for the right to examine the children periodically. Such a scheme seems to me so humane
and useful (contrast it with military conscription) that once people had become used to the idea, I think it would be socially
acceptable. What do you feel?
If you wish do please show our letters to your colleagues. I would be interested in their reactions.