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No one is particularly surprised when two people with the same level of education — or even two people who graduated from the same college with the same degree, like my wife and I — become romantically involved. But what would it mean for America, where the more and less educated are drifting apart in countless other ways as well, if this “assortative mating” tendency rose continuously for decades?


We are destined to find out, because that is exactly what is happening. And while the highly educated pair off and marry before having children, the less educated have become more likely to have kids out of wedlock or divorce later. These trends, combined, could one day prove a substantial obstacle to social mobility.

It’s tricky to measure changes in assortative mating over time, but one simple way is to track what percentage of married couples share the same level of education. That number rose about ten points, to roughly 55 percent, between the 1960s and 2000, according to data compiled by sociologist Robert D. Mare.

Such an approach ignores important factors — more Americans are going to college while fewer fail to graduate high school, and the gender ratios on college campuses have shifted from a male skew to a female one (a majority of students are now female). These changes would affect the likelihood of matched marriages even if brides and grooms were paired off at random. But most of the more sophisticated measures also indicate that assortative mating is on the uptick. And it’s rising whether you look at married couples or at couples with children regardless of whether they’re married.


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There are several reasons this may be happening. One is that the character of marriage has changed: It was once an economic arrangement in which men worked and women took care of domestic tasks; now, it’s a way for people with similar interests to share life together. Another reason is that more women have entered colleges and high-paying occupations, where they are more likely to meet similarly skilled men (who in turn now consider earning potential when selecting a mate). It’s practically cliché to say it, but bosses once married their secretaries and doctors married nurses. Now, rich men marry their working-world equals.

Still another suspect is economic inequality, which has risen along with assortative mating: As the rich get richer, they might also become less likely to mingle with the rest of us. This idea gets a boost from “Educational Homogamy in Two Gilded Ages,” a new paper from Mare showing that assortative mating was similarly high in the early 1900s. The fact that assortative mating and inequality fell together in the first half of the century, in addition to rising together in the second half, makes it harder to dismiss the correlation as spurious.


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Last time assortative mating and inequality were high, the advent of the Great Depression, World War II, and then the economy of the 1950s brought the trends back to earth. But absent another societal upheaval driving the rich and poor closer together again, these phenomena may sustain themselves this time.

One result of assortative mating could be a further increase in inequality as people with high incomes combine them. This effect isn’t as strong as one might think — for example, today’s level of inequality would not change much if we reverted to the degree of assortative mating that was found a half-century ago. A blockbuster 2014 paper claiming otherwise was later quietly corrected.


#share#But at the other end of the income scale, things are not so sanguine. When the authors of the aforementioned paper corrected their much-publicized finding about assortative mating, they also noted that divorce and unmarried childbearing have substantially increased inequality. In a separate study, they posit that “marriage decisions” in general can explain about 19 percent of the rise in inequality that occurred between 1960 and 2005.

Perhaps even more important is the effect of marriage patterns on mobility. As with inequality, the sky is not falling, at least not yet: Despite a widespread anxiety that the American Dream is dead, social mobility has apparently not fallen in recent decades, as demonstrated in “Is the United States Still a Land of Opportunity?” a paper published at the American Economic Review in January 2014. But it remains a fact of life that children of the rich are unusually likely to grow up to be rich themselves, while poor kids are more likely to grow up to be poor. Frighteningly, almost regardless of why this happens, modern trends in marriage could make it worse.

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Genes certainly play a role in children’s outcomes. The modern economy heavily rewards certain traits, such as intelligence and social skills, and decades’ worth of research demonstrates that these traits (and indeed most human traits) are partly genetic. A child’s chances for a prosperous future, therefore, go up if he has a parent who naturally possesses these traits, and even more if he has two. Some estimates suggest that genes constitute about two-fifths of the reason that rich parents have rich kids.

That still leaves three-fifths, of course, and the environment a child experiences matters, too. According to a massive, disturbing new analysis of cognitive-test scores, in fact, it may especially matter for poor children in the U.S.: Something seems to be keeping these kids from fulfilling their genetic potential. Exactly what in the environment makes poor (or rich) kids end up as poor (or rich) adults is an open question, but there are several major contributors that might help explain the trend.

Kids are better off when they are raised by two married parents. And illegitimacy is a major fault line between educational groups.

One is family structure itself. Kids are better off — and, if poor, more likely to achieve upward mobility — when they are raised by two married parents. And illegitimacy is a major fault line between educational groups; again, the college educated are getting married and staying married, while less-educated parents often have their children out of wedlock. In America, unmarried parents typically do not stay together through the baby’s childhood, compounding the effects of assortative mating: Instead of two parents with low levels of education at home, the child gets only one, often with the mother’s subsequent romantic partners as well.

There is also a “parenting gap” at work. Less-educated parents talk and read to their kids less, discipline them more harshly, and so on. Assortative mating means that when a child ends up with one such parent, he’ll likely get another one too, again assuming two parents are even in the picture.


Parents also frequently use their connections to get their kids jobs. One study of Canadian men showed that by age 33, 40 percent of them had worked somewhere that had also employed their fathers. The number rose to almost 70 percent for those with dads in the top 1 percent. Add working moms and assortative mating to the picture, and many well-off kids could have twice as much of an advantage as this suggests.

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Rich parents have other ways as well to engage in “opportunity hoarding” — giving their kids a leg up over similarly talented poor kids. These include everything from securing “legacy” college admissions to sending monthly checks to sustain Junior during his stint at an unpaid internship. Once again, two well-to-do parents — with, for example, two alma maters, or double the clout at one — can combine forces in ways that a randomly matched couple couldn’t.

And of course there’s plain old money, which brings with it better nutrition, better neighborhoods, better child care, and better schools, among other perks. Obviously, two high incomes are better than one high income — and better still than one or two low or sporadic incomes.

#related#None of this means that social mobility has ended. Thanks to the randomness of life, there will always be bright, talented, and driven poor kids who buck the odds. Because the rich are less fertile than the poor, they in effect leave spaces at the top that must be filled in the next generation. And again, while these trends are already several decades in the making, they don’t seem to be reducing mobility or increasing inequality yet. Yet it’s hard to deny that that these trends are troubling nonetheless.

This is not the place to offer a comprehensive agenda for promoting mobility, but one good starting point is a new report issued jointly by the conservative American Enterprise Institute and the liberal Brookings Institution. It is especially promising not just because it offers a bipartisan perspective, but also because it attacks the problem in multiple ways. It offers ideas for reducing unmarried childbearing, improving the environments that children grow up in (both at home and at school), ensuring that bright poor kids can enter careers that fit their abilities, and helping low-skill adults support their families without undermining their incentive to work. There’s a lot to disagree with, from the left as well as the right, but it provides an excellent framework for thinking about the issues involved.

Life will never be fair; a person’s success will always depend, to some extent, on the circumstances of his birth. But it does not bode well that our society is increasingly segregated by educational credentials.

— Robert VerBruggen is a National Review contributing editor and the editor of RealClearPolicy. Twitter: @RAVerBruggen