Minnesota Transracial Adoption Study examined the IQ test scores of 130 black or interracial children adopted by advantaged white families. Here we had black kids, raised since babyhood, in middle to upper-middle class white households. Immersed in white culture all their lives. Going to white suburban schools.
At 17, their IQs were tested. Average IQ of kids with two black biological parents: 89.
“The results of the transracial adoption study can be used to support either a genetic difference hypothesis or an environmental difference one (because the children have visible African ancestry). We should have been agnostic on the conclusions...”
I wonder if the “ghetto culture” is real like we see on the Hallmark Channel - where the black kids start out wanting to work hard, study, etc. but then peer pressure from other blacks wear them down?
Years ago I grew up in lily-white suburbia city. We had two black kids at my highly-ranked high school. They were brought in from the city. They were VERY bright kids and popular.
At 17, their IQs were tested. Average IQ of kids with two black biological parents: 89.
If we really wanted to actually know the true impact of genetics on IQ and similar methods of ranking intelligence, there would be many studies like you mentioned, as well as twin studies that could actually answer the question. The reason there is not a large body of work on this subject that we could look at is because no one really wants to know. If we actually had good, hard data on the subject, it would upset a bunch of folk's preconceptions. Also, if we actually could conclusively show that, for example, folks with green eyes were on average less intelligent than your average person, that knowledge could very well lead so some assumptions, and social policy that would not be beneficial, because it would ignore the simple and demonstrable fact that no one is 'average'.
Important brain development happens in the womb. Certain nutritional elements can mean that your baby is going to be smarter than babies who do not receive them, as well as the benefit of an overall good diet is important. A young, unwed mother may likely not be eating that well, due to lack of knowledge and immaturity, as well as income issues. Things that the uneducated and immature often do such as smoking and drugs can also hinder healthy brain development.
Therefore, even before a child is born he/she can have a huge disadvantage concerning IQ, brain development that are cultural and not necessarily due to genetic issues, even though genes/epigenes can also be impacted by cultural issues.