Whenever President Obama rails against income inequality, he offers the usual suspects as playing a major or minor role: the decline of unions, a low minimum wage, tax cuts for the rich, skyrocketing CEO pay, globalization.
But he never blames love. Or, to be more specific, he never blames the growing tendency of marriages to be between people of similar backgrounds. Doctors no longer marry nurses, they marry fellow doctors or others of comparable education level. A 2006 New York Times article examined possible reasons behind the trend:
For one thing, more couples are meeting in college and other educational settings, where prospective mates come prescreened by admissions committees as discerning as any yenta. … Secondly, men and women have become more alike in what they want from a marriage partner. This convergence is both cultural — co-ed gyms and bars have replaced single-sex sewing circles and Elks clubs — and economic. Just as women have long sought to marry a good breadwinner, men, too, now find earning potential sexy. “There are fewer Cinderella marriages these days,” says Stephanie Coontz, author of “Marriage, a History.” “Men are less interested in rescuing a woman from poverty. They want to find someone who will pull her weight.” … And finally, there’s what Schwartz calls the growing “social and economic distance” between the well educated and the less so, a gulf even ardent romantics may find difficult to bridge.
Perhaps not surprisingly, the increase in such assortative mating has a big effect on income inequality. Here is the conclusion from the new study; “Marry Your Like: Assortative Mating and Income Inequality” by Jeremy Greenwood, Nezih Guner, Georgi Kocharkov, and Cezar Santos:
Has there been an increase in positive assortative mating? Does assortative mating contribute to household income inequality? Data from the United States Census Bureau suggests there has been a rise in assortative mating.
Additionally, assortative mating affects household income inequality. In particular, if matching in 2005 between husbands and wives had been random, instead of the pattern observed in the data, then the Gini coefficient would have fallen from the observed 0.43 to 0.34, so that income inequality would be smaller.
Thus, assortative mating is important for income inequality. The high level of married female labor-force participation in 2005 is important for this result.
(Quick note on the Gini index: 0 represents total equality and 100 represents total inequality.) In other words, if people in the 2000s married the way they did back in 1960, income inequality would be about the same as it was five decades ago despite all that other stuff Obama frequently mentions. Again, the study: “So, if people matched in 2005 according to the standardized mating pattern observed in 1960, which showed less positive assortative matching, then income inequality would drop because income is more diversified across husband and wife.“