What is the role of heredity and environment in intelligence?
Perhaps 50% of your intelligence range is determined by heredity, but the rest is up to environmental factors. Thus you will see correlations of IQ going both ways with SES, for instance, and heredity. Knowing the kinds of items on verbal IQ tests, it is no surprise that kids from higher SES homes with two parents tend to do better than those from lower SES and single-parent homes. A stimulating home environment is associated with higher IQ, meaning parent interact frequently with their children, make numerous learning and reading materials available, encourage the development of new skills, use complex linguistic structures in conversation, and so on. That is more likely to happen with better educated parents who have more financial resources. Does it mean their kids are smarter? Not really, just that they score more highly on the IQ test. It is things like home environment (due to SES factors, generally), differences in early nutrition (also SES related), test bias, and the motivatio