We have also learned in recent years that the actual expression potential of genes--however they are defined-is much more limited than previously thought. The science of epigenomics now informs us [..] that methylation arrangements acquired by individual organisms can be passed on--in essentially Lamarckian fashion--to their progeny. Perhaps the most famous study of relevance involved malnourished women who became pregnant during the Dutch famine of 1944. Later, their grandchildren-although reared by prosperous and well-nourished parents--were born abnormally light.

Traditionally, scholars--including most scientists-have offered culturally-based explanations of personality and cognitive traits. But according to Cochran and Harpending, the nurture approach runs into persistent problems when trying to elucidate why pre-agricultural or shallow farming societies are slow to modernize. [..] biological and thereby cognitive inequality between human ethnic groups should come as no great surprise. [..] That biological fact, they infer further, is why Ashkenazi (Hebrew for "German") Jews "have the highest IQ of any ethnic group known" (averaging 112-115 points, compared to the European norm of 100), and "are hugely overrepresented in those jobs and accomplishments with the highest cognitive demands."