Segregation Returns to US Schools

**Montmorency** · 05-21-2014, 10:26

Intelligence: New Findings and Theoretical Developments (Nisbett et. al. 2012)

We can be conﬁdent that the environmental differences that
are associated with social class have a large effect on IQ.
We know this because adopted children typically score 12
points or more higher than comparison children (e.g., siblings
left with birth parents or children adopted by lower
SES parents), and adoption typically moves children from
lower to higher SES homes

[...]

Hart and Risley also found a
large difference in the ratio of encouraging comments made
to children versus reprimands. The child of professional
parents received six encouragements for every reprimand,
the child of working-class parents received two encouragements
per reprimand, and the child of unemployed African
American mothers received two reprimands per encouragement

[...]

It is almost surely the case, however, that a substantial
fraction of the IQ advantage is due to the environments
independent of the genes associated with them. This is
because we know that adoption adds 12–18 points to the IQ
of unrelated children, who are usually from lower SES
backgrounds

. See Nisbett, 2005, 2009,
for the view that the direct evidence indicates that the
difference between the races is entirely due to environment.)

Nisbett (2009) maintains that there is actually a substantial
amount of direct evidence stemming from the fact that the
“Black” gene pool in the United States contains a large
amount of European genes. He maintains that almost all the
research indicates no higher IQs for Blacks with a significant
degree of European heritage than for those with much
less. One of the most telling of the studies was available at
the time of the Neisser et al. (1996) report but was apparently
not known to them. This is an adoption study by
Moore (1986). She examined the IQs of Black and mixed
race children averaging 81⁄2 years of age who were adopted
by middle-class families who were either Black or White.
The children who were of half-European origin had virtually
the same average IQ as the children who were of
exclusively Black origin. Hence European genes were of
no advantage to this group of “Blacks.” Children (both
Black and mixed-race) adopted by White families had IQs
13 points higher on average than those adopted by Black
families, indicating that there were marked differences in
the environments of Black and White families relevant to
socialization for IQ; indeed, the differences were large
enough to account for virtually the entire Black–White gap
in IQ at the time of the study.