In President Obama’s State of the Union speech tonight, we’re sure to hear a lot about inequality—the issue is already the centerpiece of his second term, and he has invoked the widening wealth gap in his push for everything from a higher minimum wage to expanded early childhood education and an infrastructure bank. If Republicans stay on script, their response to Obama is likely to lean heavily on a different solution: marriage.
“The truth is, the greatest tool to lift children and families from poverty is one that decreases the probability of child poverty by 82 percent,” Florida Republican Senator Marco Rubio—and presumed presidential hopeful—recently pronounced. “But it isn’t a government spending program. It’s called marriage.”
Whether merely getting married lifts the financial prospects of the poor, as Rubio is arguing—or whether it’s just something that people who already have good financial prospects do at a higher rate because they make more attractive marriage candidates—is up for debate. But there’s another, less discussed way that marriage and inequality are tied up: assortative mating. The term has a strong ethological ring to it—zoologists use it to describe animals with strong preferences about what their mates look like. Social scientists use it to describe human behavior: our custom of marrying not people who look like us, but who have résumés like ours. People, in other words, tend to pair off with those who have a similar educational background and similar earning power. Doctors marry other doctors, lawyers marry other lawyers, Ivy league graduates marry other Ivy league graduates.
Apparently we’re doing so more and more these days. A working paper by University of Pennsylvania economist Jeremy Greenwood and others mined U.S. Census Bureau data and found that assortative mating has steadily increased since 1960. What’s more, the phenomenon has exacerbated household income inequality.
To measure the impact of assortative mating, the economists ran a counterfactual. They compared the American Gini coefficient—an income distribution yardstick—to what the Gini coefficient would have been if people just married randomly in 1960 and in 2005. In 1960, they found, purely non-assortative mating would barely have made a difference in household income inequality. In 2005, however, it would have made a pronounced difference—if Americans were marrying without regard for their mates’ financial prospects, the U.S. Gini coefficient would drop from .43 to .34. (In the Gini coefficient, lower is more equal: Scandinavian countries tend to come in around .25.) A Gini coefficient of .34 means that without marital economic self-segregation, the U.S. would have the income distribution of Great Britain—which the U.S. itself had back in 1960.
Liberals respond to this sort of research by pointing out that the widening of the income gap in the U.S. comes from the very top of the scale—the top 1 percent or 0.1 percent, rather than the top 5 percent. These aren’t two-doctor households, in other words, but hedge-fund managers and tech entrepreneurs; assortative mating has little to do with their huge paydays. Still, if Greenwood et al’s results are correct, those merely well-off two-doctor and two-lawyer households are playing a role in the hollowing out of the American income scale.
Blogger Steve Randy Waldman has argued that assortative mating—he calls it, more succinctly, homogamy—also helps explain the rise in single motherhood at the lower end of the socio-economic spectrum. As everyone with good earning potential pairs off with each other, all that’s left are the less promising prospects, and more and more women make the understandable choice to go it alone rather than hitch themselves—theoretically for life—to someone who is going to be financial and emotional dead weight.
It’s not the sort of problem that lends itself to policy interventions. At a time when fewer and fewer Americans think the government should tell someone what gender their mate should be, it’s hard to see much appetite for the government’s telling people they should really marry someone from a different educational caste. Besides, assortative mating is driven in part by changes that many Americans would celebrate—most prominently increased educational and occupational opportunities for women. Rather than staying at home not earning anything, they’re going to elite colleges and graduate schools, where they meet other members of the educational (and soon-to-be professional) elite.
Of course, the rise of the two-earner household is only partly a story of increased opportunity. It also has a lot to do with necessity, as middle-class households sent a second earner into the job market to keep up with the rising cost of living in an age of stagnating wages.
Since the sort of well-paid, low-skill manufacturing jobs that sustained the middle class in the mid-20th century are unlikely to come back, the marital self-selection of the elite is likely to continue to drive inequality. That is, unless we as a national society simply decide to take more of the income of the rich to give to the poor, or figure out a way to get more people into the high-earning educational elite without simultaneously saddling them with crippling debt. Meanwhile, we’re left with the discomfiting possibility that in an era of stagnating middle-class wages and high-stakes university admissions, the ideal of a marriage of equals is helping to make us a less equal nation.