There have been several attempted replications of the
SES by heritability interaction since the Turkheimer et al.
(2003) study was published, with mixed results. (A study
by Nagoshi and Johnson [2005] has been cited as a failure
to replicate the SES interaction [Rushton & Jensen, 2010],
but it is not. Nagoshi and Johnson used the Hawaii Family
Study to demonstrate that there is no change in parent–
child correlations for intelligence test scores as a function
of family income. Parent– child correlations, however, are a
combination of genetic and shared environmental factors.
Every instance of the interaction that has been reported to
date has shown that genetic and shared environmental
components change in opposite directions as a function of
SES, so one would expect them to cancel each other out in
parent– child correlations.)