“OFFICE MEMORANDUM © STANFORD UNIVERSITY @© OFFICE MEMORANDUM e© STANFORD UNIVERSITY @ OFFICE MEMORANDUM

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Date: November 30, 1971

Jim Spuhler
Center for Advanced Studies

L. L. Cavalli-Sforza.

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I am sorry that I have not yet been able to see you since you arrived at
Stanford, but as you might know, during the last month I have been bedridden
with a cervical column condition. This does not, however, reduce to zero
my activity and if you were prepared to make sometime a visit (more-or-less
any time of the day and on short notice) to my home, 1 would certainly
appreciate it.

I am not quite aware of what your plans for this year are, although 1
understand that they should center largely on the kind of problems in
which Walter and I wrote an elementary sort of article in Scientific
American some time ago. Although I can continue with a relatively
satisfactory amount of activity in spite of spending most of my time

in bed, I certainly am in the worst condition for doing any type of
bibliographic research. Some problems about IQ and environment have

been bothering me lately, and I wonder if by chance in your experience
with the literature you can indicate to me some references on the follow-
ing points which seem to me of the greatest importance. I know that there
is something in the literature, but I am really interested to know if there
is research which is of sufficient quality both from the point of view of
the collection of the data and of the statistical analysis made to give
rise to satisfactory solutions. The problems are to some extent diffi-
cult, one more than the otherS and I would like to have access to the best

sources, if any.

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The first point, perhaps the most difficult one, is the relationship «
between spacing of children and IQ. It is clear that it is not easy

to separate this from overall fertility in terms of the total number

of children, nor from socio-economic class. What I am really interested
in is the time that the mother has to spend with the child, and the
effect this has on the child's IQ. I would be especially interested in
being able to see the effect of births following very closely one another,
say one year or a little more, on the IQ of either of the child who was
born first or of the child who was born last. It seems to me that amount
of parental care has not been studied very extensively. Naturally, it is
possible that rather than amount of parental care, it is the quality of
parental care that counts, but this is probably even more difficult to
study. It seems to me that this may be one of the most important environ-
mental factors worth studying, and they could be studied in more than one
racial group. It is likely also that parental care is greatly different
because of cultural inheritance in different racial groups and may have
substantial effects on IQ development.

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If it is found that shorter spacing lowers IQ (other factors being equal),
one could thus explain at least part of the lower IQ of twins, and the
even lower one of triplets.

The second point is simpler. I would like to be ccnvinced that it is

true that the IQ of black children is relatively higher at the beginning

of school and then tends to drop, while that of white children should
remain constant. In particular, such data might mean that the schooling

of black children is worse. This is a likely fact, but of course not easy
to measure. Data of this kind would be especially interesting if they could
come from schools that are really desegregated and where there is an
approximately equal proportion of whites and blacks or in which, at least,
the proportion is known. Naturally, if such data are taken from the popu~
lation at large, they might mean anything.

Finally, in a letter to Scientific American -- I am enclosing a Xerox of

it as you may find it amusing if you are not already familiar with it --
in which Shockley answered our article, he cited some evidence of the
correlation between per cent black-white admixture and IQ. What references
do you have on this?

If you have any information on these points, I would be grateful for
references. If you happen to have a free half hour to spend here, I would
certainly welcome that. I live very close to the Center at 736 Mayfield,

and my home telephone number is 327-0227. Please give my best regards to
all friends at the Center.

Yours sincerely,
buce

L. L. Cavalli-Sforza

ec: Drs. Lindzey & Lederberg