With regard to racial differences in iqs, the work of african american demonstrated the strong effects of environment. herrnstein goddard murray terman bond

I believe the answer is: Bond
Bond argued that the culture/tradition in the place where we grew up in could play a crucial roles in our IQ development.
For example, if we grow up in poor neighborhood with high crime rates among youngsters, we would became less likely to did things that enhance our iq development since early age.