Re: OT: Racialist evolutionary psychology

"Manuel Doria" <manueldoria@xxxxxxxxx> wrote in
news:1158118714.969325.159890@xxxxxxxxxxxxxxxxxxxxxxxxxxx:

First of all, sorry for my blatant confusion: where I've written
"K-selected" switch for "r-selected" and vice versa.

Twin studies fail to isolate genetic effects from the effects of one of
the environment in which the most crucial stages of human development
happen: the mother's womb.

I've read in Matt Ridley's _Nature via Nurture_ that a control measure
used in those studies is to compare the results achieved with identical
twins with those from dizygotic twins, would it still not be enough to
isolate at least the majority of the pre-birth environmental influence?

Yes. There is little question that intelligence is heritable. And, contrary
to some other follows, intelligence is perceived as an important trait by
most cultures. Humans, in fact, practice assortative mating with
intelligence one of the critical parameters. However, the fact that a trait
is highly heritable does not mean it is not subject to environmental
influence. Height is highly heritable, but is still strongly affected by
nutrition. Moore's "The Dependent Gene" has a good discussion of this
topic.


It has been shown that mother's nutrition, health and lifestile affect
various aspects of the fetus development, usually causing life-lasting
effects.
There is no reason to assume that brain development is an exception.


Rushton is quite aware of this, and uses data on twins reared apart and on
adopted children to bolster his point that environmental influences are
still not enough to overcome the genetic effects. Unfortunately for his
case, there is no data on twins reared apart, one of whom is white and one
of whom is black.

There is, however, data on children of mixed marriages between black
American soldiers and white Germans raised in Germany. This data does not
show any racially based IQ differences. As I understand it, Rushton tries
to dismiss this data because it includes a large number of blacks of North
African descent, but I haven't looked into the subject in any great detail.

The data used from what I've understood is collected from entire
populations, heterogenous in social status; an interesting test that
could be proposed is to obtain data solely from, for instance, poor
caucasians and african americans with high social conditions. Otherwise
there is no way of knowing the importance played by genetics on the
traits he selected for his model.

One of the interesting results of IQ tests that tends to be ignored by
proponents of the racial difference hypothesis is the results from some of
the first large-scale IQ testing, that of US army recruits in the First
World War. Whites scored higher than blacks - but when aggregated based on
geography, northern blacks scored higher than southern whites. This
suggests either a cultural or socioeconomic bias in the test results.



His model is also very criticized because it doesn't accurately explain
why native americans seem to be an exception from his proposed r/K
continuum. It seems that the last book of Richard Lynn, which follows a
similar partly genetic explanation for race differences on
intelligence, attempts to explain the case of native americans.

And struggles to do so, as I recall. Although it is interesting to note
that both asians and native americans scored higher on mathematical
ability. In fact it is not unlikely that there are genetic differences in a
number of the many types of intelligence that make up overall human
"intelligence". As noted below, accurately measuring those differences is
another matter entirely.


IQ tests measure your ability to conform to the way of thinking of the
authors of the test.
Those tests have often question to which there isn't a demostrabily
correct answer.

And with practise at solving the particular types of puzzles which are
common in IQ tests, higher scores can be reached without meaning that
your neurophysiology suffered a drastic modification or something
similar.


Yes, and another conundrum that Rushton tries (unsuccesfully in my opinion)
to explain away is the fact that raw IQ scores (those uncorrected to the
100 average value) have risen for all races over the last century. Does
this mean that we are genetically getting smarter? Probably not, since
genetic changes shouldn't work that fast (there may be momentum effects,
but that is another story). Again the likely answer is cultural bias in the
tests.

Another follower noted IQ tests based on knowledge of black culture. I
would also love to see an IQ test designed by hunter-gatherers. My guess is
that you and I might struggle to identify the spoor of different species,
even though it is just pattern recognition.

Yours,

Bill Morse

.

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