Social inequality and assortative mating: Cause or consequence?

Johnson et al. (Behav. Genet.17:1-7, 1987) have interpreted an apparent decline in assortative mating for educational attainment in Hawaii as being a consequence of increased social mobility and increased access to higher education. Data on the educational attainments of adult twin pairs and their spouses from the Virginia twin registry are reported which give no indication of a major decline in the intensity of assortative mating. A previous study of a Norwegian population (Heath et al., Behav. Genet.15:349-369, 1985), in which an increase in equality of educational opportunity had been documented (Heath et al., Nature314:734-736, 1985), observed remarkable constancy of the marital correlation for educational attainment. There is thus little evidence that decreases in social inequality in a society lead to a decline in assortative mating.