For a good review of the empirical findings refer to Deary et al. The neuroscience of human intelligence differences. There is some debate as to whether represents a causal entity or whether it is epiphenomenal.
For a good discussion of this, refer to: Gottfredson, 2010.
2) Tested differences in psychometric intelligence, specifically in , must represent measurable, functionally important differences within and between populations (VI-VII).
When the Human Genome Project states that “DNA studies do not indicate that separate classifiable subspecies (races) exist within modern human,” they are talking about biological taxonomic classifications and saying that there are no population specific genes that would warrant classifying various populations as subspecies. According to Lewontin (1972), RISC means that racial classification are of “virtually no genetic or taxonomic [superfamily to subspecies] significance.” The scientific community has since rejected the notion that race, whether delineated by continental, sub-continental, or regional ancestry (lumpers and splitters), is of no such significance. (The root of “race” is “ancestry,” word games about “lactose intolerant races” notwithstanding).
The RISC hypothesis has been falsified and Lewontin’s claim about race is now know as Lewontin’s fallacy.
(Whether or not probabilistic calculations based on these means is morally acceptable, is another issue.) As such, if you are naturally at the right tail end of some measure, you are at the right tail end.
Clarification about the meaning of heritability To say that a difference is heritable is to say that, given equal conditions, individuals or groups will differ as a result of genetically conditioned endogenous factors.