PRIMATES, AFRICANS, EUROPEANS, EVOLUTION IN REVERSE?

Have there been IQ studies categorised by socio-economic background,
and access to educational facilities?If there haven't then we cannot rule out a form of bias. IQ
tests are designed to explore a particular type/style of brain
activity. Anyone who has not spent time developing that style
of thinking will do worse than those who have. This is evidenced
by the fact that people who do lots of IQ tests get better at
them, a fact which also casts doubt on both a correlation to
brain size, or the validity of the tests in the first place.In terms of the other physiological differences, most creationists
accept speciation so they shouldn't have a problem.The more interesting question, for me, raised by this thread is
covered elsewhere ... how do creationists explain the diversity
of humanity given that we have so few 'common ancestors' (Shem,
Ham, Japheth and wives)?

Was that lower or higher IQ than the adopted parents,
or a mixture of both?Has similar research been conducted with natural children too?

Fair enough ... I'll have to stop being lazy and look it
up myself