Re: Race, Head Size, And IQ

Danny Yee (danny@STAFF.CS.SU.OZ.AU)
Mon, 7 Nov 1994 17:56:35 +1000

> Rushton here on neuroscience data and anthropology theory

> 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.

Let me see. Well off family => better fed mother => bigger baby
Well off family => more time to play with baby => baby better at
puzzles

Not once have you mentioned any attempt to control for effects like this.

> 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.)

Of course IQ scores are good predictors of educational success -
children who do well on IQ tests get to go to better schools, get
better treatment from teachers, and get a big boost in self-esteem.

IQ measures ones ability to do IQ tests. IQ scores are not magic
numbers attached to people in any essential fashion. Intelligence is
something completely different, and not something that is either
simply quantifiable, or even a unitary "thing".

> 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.

Exactly what are we splitting 50/50 or 100/0 here?

CAUSALITY IS NOT ADDITIVE

Please repeat five times before going to bed each day.

And what is this genetic/environmental dichotomy? I don't suppose you
have any idea just how complicated human ontogeny is?

> 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.

This is not the debate of the decade. This is just bad science in a
centuries old tradition.

I'm with Mike Lieber on this one. The debate on this list isn't what
scares me - the people here have the knowlege and critical training
to make up their own minds - but the effect this sort of stuff has
on the population at large. For someone who hasn't had experience
with critical thought and scientific practice and doesn't have any
background knowledge in anthropology or genetics, how easy is it going
to be to see Rushton's arguments for what they is? Even if we calmly
provide intellectual counter-arguments, most people are not going to
be able to tell who's talking sense. Sometimes one just has to fight
with ridicule and sarcasm and use less reflective means of argument.

Danny Yee.