J. Philippe Rushton (RUSHTON@SSCL.UWO.CA)
Fri, 4 Nov 1994 20:42:03 -0500

First, the President of the Educational Testing Service has also
issued a press release stating that their tests are not tests of
intelligence and do not bear on the issue of nor can be used for
examining whether genetics underlie group differences in IQ. They
criticize Murray for implying otherwise. More attempts at damage
control by PC.

Good luck trying to get APS or even BGA to take a firm stand on this
overly sensitive issue.

Here are my own thoughts on why genes underlie the black-white-Asian
gradient in AVERAGE differences (with no predictions to any particular

1. The evidence goes well beyond the simple syllogism usually
provided that (a) IQ test scores are heritable in black, white, and
Asian populations, (b) Asian IQs are higher than white IQs which are
higher than black IQs, so (c) the Asian-white-black differences are
partly heritable.

2. Although the black-white IQ gap averages at 15 points, the
difference is greater on some items and subtests than on others. The
difference is smallest on more environmentally influenced items
(repeating 4 digits forward; knowing the meaning of words or place of
capital cities) and greates on more heritable items (repeating 4
digits backward; mentally rotating a 3-dimensional drawing).

3. This is the opposite of what is predicted by a purely
environmental argument. It is evidence such as this that has led many
(a plurality, most) experts in psychometrics to conclude that part of
the black-white difference in IQ is genetic.

4. The more genetically weighted an item or subtest is the more it
differentiates blacks from whites. These genetic weightings are
established by examining the effects of inbreeding in cousin
marriages, which depresses scores on some subtests more than on
others, as well as by examining the similarities of twins and other
siblings. Moreover, the black-white difference in IQ scores is
directly associated with a black-white difference in head size (and by
inference, brain size). For example, black and white children matched
for IQ scores do not differ in head size.

Brain sixe differences established using three converging procedures
(autopsy, endocranial size, external head measures) show the racial
gradient and magnetic resonance imaging (MRI) techniques and head
perimeter measures show that brain size correlates with IQ scores.

Trans-racial adoption studies show that Korean children adopted by
white parents grow to have IQ scores higher than white children
whereas African children grow to have lower scores than white
children. Adopted children with two black biological parents fare
worse than adopted children with one white and one black biological

Much additional evidence for the genetic hypothesis is reviewed in my
book Race, Evolution, and Behavior (Transaction, New Jersey). The IQ
gradient is to be observed in Africa, the Caribbean, Europe, the
Pacific Rim, the USA, and now also here in Canada in English Speaking
Toronto and French Speaking Quebec. (It would be interesting to see
studies of Communist Cuba cut off from elsewhere for 30 years and a
very multi-racial society).

The universality of the pattern calls into question traditional
explanations based on white racism, colonialism, the legacy of
slavery, and other factors specific to particular regions. Hong Kong
is still a white colony and virtually without natural resources and
yet thrives because of its human capital.

It has to be accepted that evolution produces populations with
different profil profiles of strengths and weaknesses.

Phil Rushton
University of Western Ontario
London, Canada