Direct marital assortment for cognitive and personality variables.

Recent advances in linear modeling in human genetics permit the resolution of the sources of assortative mating. Using these methods we examined the multivariate assortment relationships among education, general cognitive ability, and personality traits in two large samples of spouses from the Colorado Adoption Project (N = 334 couples) and the Hawaii Family Study of Cognition (N = 1165 couples). Results indicate a direct pairing of mates on the basis of educational level and general intelligence but no cross-assortment between the two. Thus, the indirect marital correlation between education in one spouse and intelligence in the other is due only to the direct pairing on education and on intelligence and to the within-person correlation between the two traits. We also found direct isomorphic assortment as well as direct cross-assortment on some personality characteristics. However, there was no cross-assortment between the personality and the cognitive domains. Results from models