Letter from John T. Edsall, Fogarty International Center to Francis Crick
Edsall here continued his discussion with Crick 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 Edsall here responded to Crick's call for a "Twins Institute" that would encourage parents of identical
twins to give up one twin for adoption as a way of expanding the pool of subjects for studies on identical twins raised separately.
To scientists, such studies were ideally suited to distinguish the effects of heredity and environment on human development.
Number of Image Pages:
2 (147,043 Bytes)
1971-04-30 (April 30, 1971)
Edsall, John T.
Fogarty International Center
Original Repository: Wellcome Library for the History and Understanding of Medicine. Francis Harry Compton Crick Papers
I have been very busy, and hence slow in responding to your letter of 29th March. Also I am about to leave for three weeks
in Europe, so I will reply briefly.
The Twins' Institute might provide valuable additional data; much has already been learned from the study of twins, and
much more can certainly be learned. I would hesitate to encourage people to give away one of the pair of twins for adoption;
if the parents can bring up both twins, it is usually better for the children. But certainly more systematic efforts to study
twins brought up separately would be worthwhile.
As to intelligence, I am quite sure that no one can have high intelligence unless he has a favorable constellation of genes.
There may be a great many such favorable combinations; intelligence is not a single entity. In any case, a child of potentially
high intelligence may be converted into an idiot by a brief cutting off of the oxygen supply to the brain during a difficult
birth. Malnutrition in early childhood may damage intelligence irreversibly; and there are almost certainly social and psychological
factors that may, operating in childhood, prevent the individual from rising to anything like his full potential. Thus the
situation is, I think, highly complex. It is even more complex when one considers the hereditary and environmental factors
involved in the development of character traits such as kindness, generosity, and sense of responsibility. Research in this
field is bound to give results slowly, even if you pour a lot of money into it.
There is a matter of priorities here. I think, for instance, that stopping human population growth is a matter of the highest
priority, and enormously difficult. It deserves a far higher priority, to my mind, than the issues raised by Jensen and Shockley.
I am not against eugenics in principle; within a generation, as knowledge of human heredity advances, we may be in a position
to begin an effective program of positive eugenics. Eugenics has got a bad name because some people tried to push it at a
time when there was not adequate scientific basis for doing so; and of course it had the misfortune that the Nazis promoted
something to which they gave the name of eugenics. But at present I believe that the problem of human numbers is overriding;
the most urgent problem in applied biology is to control that; and of course that also involves social and psychological problems
that go far beyond pure or applied biology.