As Charles Murray noted and predicted years ago, marrying someone with the same level of education has gotten more popular:
The paper’s authors, led by Jeremy Greenwood at the University of Pennsylvania, mined census data from 1960 to 2005 and found that people’s tendency to marry someone of the same education level as their own increased steeply. After taking into account the increases in the education levels for men and women that have occurred between 1960 and 2005, the odds of a college-educated male marrying a college-educated female rose by 12 percentage points.
One more factor behind radical economic and social inequality is asserting itself. I wonder sometimes if this is not also behind some of the cultural and political polarization that plagues us. The more the educated group marry and hang out with each other, the less contact they are likely to have with people outside their purview. How many real friendships, for example, does a college graduate have with someone who didn’t finish high school? If you don’t marry across these gulfs, and your social circle naturally has few people in it who can speak to their own experiences in the truly struggling middle class, how can we begin to cross the red-blue divide?
It’s not that this divide isn’t crossed daily, nor that assortative mating makes it impossible, nor that milder versions of this didn’t always happen. It’s just that so many trends, now exacerbated by this one, are making “one nation” increasingly difficult to sustain. What potent social and economic trends are bringing these two nations together? Reality TV? Millman finds that the shift is largely due to women’s preferences changing:
[W]omen’s preferences have come to match men’s preferences over the 45 years in question. In 2005, the percentage of highly-educated women willing to marry men with a low education was essentially identical to the percentage of highly-educated men willing to marry women with a low education. In 1960, women were much more willing than men to “marry down” educationally-speaking.
Drum qualifies the study by noting that “that assortative mating has actually increased only modestly since 1960.” And he doesn’t blame rising inequality on matrimonial trends:
[R]ising income inequality isn’t really due to a rise in assortative mating per se. It’s mostly due to the simple fact that more women work outside the home today. After all, who a man marries doesn’t affect his household income much if his wife doesn’t have an outside job. But when women with college degrees all start working, it causes a big increase in upper class household incomes regardless of whether assortative mating has increased.