Race, Head Size, And IQ

J. Philippe Rushton (RUSHTON@SSCL.UWO.CA)
Wed, 19 Oct 1994 20:35:21 -0400

of the data and inferring causality from correlations.

1. Head size and brain size correlate from 0.50 to 0.90. How could this
be otherwise if you think about it. In any case this is irrefutable.

2. Head perimeter at birth is smaller in black babies than white
babies. The largest study is the National Collaborative Perinata Project
that followed 19,000 black babies and 17,000 white babies from birth to age
7 and is ongoing. By age 7 black children still averaged a smaller head
perimeter than white children even though they averaged taller and
heavier than white children.

3. Head perimeter at birth predicts IQ scores at age 4 years and at
age 7 years in both black and white samples above with correlations
of from 0.10 to 0.20.

4. I repeat, modern magnetic resonance imaging (MRI) studies of
brain size in vivo in college students (a restricted range thus reducing
correlations) correlates 0.40 with IQ scores.

5. IQ scores are the single best predictor of educational and
occupational success that there is. If you have to wish for your child
this kind of success wish for him or her a high IQ rather than a good
education and social contacts. This is true within families, among
siblings, in both black and white families. The best evidence
for this statement is in THE BELL CURVE by R. J. Herrnstein and
Charles Murray, obtainable from The Free Press in New York (OR,
TOLL FREE 1-800-223-2336. Credit Cards. I aim to inform, not to
advertise.)

6. Nutrition, drug abuse, illness, blows to the head etc. might
all directly effect brain size, brain functioning, and scores on IQ tests.
This has never, ever been in doubt by anybody. The debate is between
people like me who advocate a 50/50 genetic/environmental causation and
those like my critics who advocate, in effect, a 100 percent environmentalist
perspective for racial group differences. Then the obfuscationalists
who believe it is all too complexly interactive or constructed to know.


7. This is the debate of the decade and you all have a duty to
be informed. At least read Newsweek this weeks cover story if nothing
else.

Cheers.