Not many juicy ones, I'm afraid. It was at the time of the
[Bell Curve's] launch. The AEI had a lunch for the press
and others. I used my status as Deputy Assistant Secretary of
the Treasury to get a ticket.
If I recall correctly (but a bunch of different meetings are
jumbled together in my mind), during the question period I asked
(a) if it was not true that differences in measured IQ accounted
for a negligible proportion of income inequality once one controlled
for a multi-dimensional measure of parents' socio-economic-status
and for education, and (b) if it was not true that the only way
Herrnstein and Murray could even claim that measured IQ was an
important cause of anything was by removing the variables--education,
more than one dimension of parents' ses--that everyone else thought
were the important causes.
I went on to assert (c) that Herrnstein and Murray's claim
that once you control for IQ that there is no sign of wage discrimination
against African-Americans was a blatant lie (they had a regression
in which predicted black and white wages were equal when the
right-hand-side variables were set at their means among whites,
but in which predicted black wages were... somewhere between
10 and 20% lower... when the right-hand-side variables were set
at their means among blacks). And then I asserted (d) that since
Murray was maintaining (i) that measured IQ was determined by
genes--barely affected by differences in children's environments--and
(ii) that measured IQ in the U.S.--in spite of a "genetic
endowment" that from Murray's perspective had been "deteriorating"--had
been growing at 0.3 points per year for the past-half century,
the only conclusion I could draw was that Murray was certainly
not one of the cognitive elite.
At that point I was told that my participation was not wanted...
Brad DeLong
There have only been 2000 or so generations since homo sapiens
sapiens headed north and south out of East Africa or the Middle
East or wherever we finally evolved.
Suppose that two diverging subpopulations headed into two
different regions, one of which gave no survival advantage to
the amount of higher intelligence conveyed by a (dominant) gene
let's call [High IQ} and the other of which headed into a region
in which having [High IQ] gave you an extra 1 in a thousand chance
of surviving to breed...
Suppose further that both subpopulations started with a population
frequency of [High IQ] of 1/20 percent--so that 0.1 percent of
each population started with a [High IQ gene].
Then after 2000 generations, the proportion of the neutral
selection pressure population with [High IQ] is still 0.1%, and
the proportion of of the high-intelligence selection pressure
population is... 0.73743%
We are a very young--and interbreeding--subspecies. 2000 generations--40,000
years--is not very long for natural selection to work without
truly enormous amounts of differential selection pressure on
different non-interbreeding populations.
In America there is a lot of intellectual garbage lying around--leftovers
from arguments (back before 1860) that slavery was an institution
designed to make the simple, childlike African-Americans better
off, arguments (from 1880-1940 or so) that segregation was an
institution designed to make the simple, childlike African-Americans
better off, arguments (from 1900-1960 or so) that it was a waste
to spend money on schools for African-Americans because everyone
knew they weren't as smart, and arguments (from 1970-today) that
large gaps in wealth and economic welfare between European-Americans
and African-Americans reflect not the legacy of past discrimination
but instead the lower native intelligence of African-Americans.
For example, you can go look at _The Bell Curve_, and find
Charles Murray arguing four things:
--intelligence test scores are hardly affected at all by differences
in the environments in which people are raised.
--the average intelligence test score of Americans has been rising
for virtually the entire past century at about 0.3 IQ points
per year.
--the (large: 15 IQ point) difference between immigrants from
Poland and Italy and native-born white Americans around 1900
was due to differences in their environments.
--the (large 15 IQ point) difference between African-Americans
and white Americans today is due to differences in their genes.
Now if intelligence test scores are hardly affected at all
by differences in environments, then Polish-Americans and Italian-Americans
have no business closing the average test score gap vis-a-vis
native-born white Americans. If intelligence test scores are
hardly affected at all by differences in environments, then there
is no way that intelligence scores can have risen by perhaps
30 IQ points over the past century.
Conversely, if intelligence test scores have been trending
upward--as they have--and if the grandchildren of immigrants
from Italy and Poland have the same test scores as the grandchildren
of WASPS--as they do--then no one has any business at all saying
that intelligence test scores are hardly affected by differences
in environments.
And if test scores are affected by differences in environments--and
if other big gaps between ethnic group average scores have gone
away as environments have become equalized--then no one has any
business at all presuming that today's differentials are anything
other than environmental.
The conclusion I reach from all of this is that Murray and
Herrnstein are certainly not members of the... shall we say cognitive
elite? And that anyone who wants to leap from the fact of large
average test score differences today to the presumption that
they have some genetic basis--that their reasoning has roots
not in evidence but in American racism.
(Unless, of course, they also want to leap to the conclusion
that grandchildren of Italian and Polish immigrants to the United
States also have a genetic intelligence deficit--or to the conclusion
that grandchildren of such immigrants would have a genetic intelligence
deficit had aliens not been using effector technology to monkey
with their genes at the fertilized ovum stage: then I would
call them not racist but consistent--and insane.)
Brad DeLong
Professor
of Economics J. Bradford DeLong, 601 Evans Hall, #3880