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Journal Issue: School Readiness: Closing Racial and Ethnic Gaps Volume 15 Number 1 Spring 2005

Genetic Differences and School Readiness
William T. Dickens

Direct Evidence on the Role of Genes: European Ancestry and Cognitive Ability

Blacks in the United States have widely varying degrees of African and European ancestry. If their genetic endowment from their African ancestors is, on average, inferior to that from their European ancestors, then their cognitive ability would be expected to vary directly in proportion to the extent of their European ancestry. Some early attempts to assess this hypothesis linked skin color with test scores and found that lighter-skinned blacks typically had higher scores. But skin color is not strongly related to degree of European ancestry, while socioeconomic status clearly is. Thus the differences might reflect environmental rather than genetic causes. Nearly all commentators agree that these early studies are not probative.

More recent studies have looked at measures of European ancestry, such as blood groups or reported ancestry, that are not visible. Such studies have found little or no correlation between the measure of ancestry and cognitive ability, though all are subject to methodological criticisms that could explain their failure to find such a link. Thus although these studies do not provide evidence for a role for genes in explaining black-white differences, they do not provide strong evidence against it.