Contemporary scholarly debate emphasizes the importance of spouse selection on population stratification, typically focusing on the traits of spouses themselves. In this study spouses and their parents were analyzed to resolve the effects of direct spousal assortment from family background assortment on three social traits that spouses correlate the highest: education, church attendance, and political affiliation.
The data set is comprised of a core of spousal pairs and their parents assessed by self-report and a more extensive set of individuals on whom there are only ratings by relatives for educational attainment, church attendance, and political preference. Structural equation models were fitted to the observed polychoric correlations by diagonal weighted least squares.
For education and church attendance, assortment was based primarily on the traits of the spouses themselves, but models including independent assortment for the traits of parents-in-law gave a better fit. For political affiliation, assortment based on social background influenced by the traits of both parents gave a better fit.
The findings demonstrate that in humans, spousal similarity may reflect processes of selection and stratification that are more complex than commonly supposed in most models for family resemblance and social diversity.