Assortative Mating And General Intelligence
An interesting finding from genetic research, which [Nicholas J.] Mackintosh mentions, only in passing [in his book "IQ and Human Intelligence"], as posing a problem in the estimation of the heritability of g, is that there is greater assortative mating for g than for any other behavioral trait; that is, spouse correlations are only ~.1 for personality and only ~.2 for height or weight, but the correlation for assortative mating for g is ~.4. In addition to indicating that people are able to make judgments about g in real life, this finding suggests that assortative mating may contribute to the substantial additive genetic variance for g, because positive assortative mating for a character can increase its additive genetic variance.
from "IQ and Human Intelligence."
Quoted on Mon Sep 26th, 2011