Social Science

Is Assortative Mating Responsible for Rising Income Inequality?

George Mason University economist Tyler Cowen suggests that it might be.

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AssortativeMating
KorenBiology

Income inequality in the United States has been rising. Various explanations have been proposed ranging from the hollowing out of the middle class as middle-skilled jobs are automated away to tax policies that favor the already rich. In his Sunday New York Times article, "The Marriages of Power Couples Reinforce Income Inequality," George Mason University economist Tyler Cowen suggests that rising income inequality is being exacerbated by the fact that highly educated people are increasingly likely to marry one another. As evidence, Cowen cites an interesting study published in 2014 that looked what would have happened to income inequality if marriage matches were still being made across the educational and income levels as they stood in 1960. From the Cowen's article:

The numbers show that assortative mating really matters. One study indicated that if the marriage patterns of 1960 were imported into 2005, the Gini coefficient for the American economy — the standard measure of income inequality — would fall to 0.34 from 0.43, a considerable drop, given that the scale runs from zero to one. That result is from the economist Jeremy Greenwood, a professor of economics at the University of Pennsylvania, and other co-authors.

Another 2015 study cited by Cowen calculated that …

… about half of the expected financial gain of attending college derived not from better job prospects but from the chance to meet and marry a higher-earning spouse.

Cowen rather coyly overlooks another aspect of the assortative mating that takes place at universities: The heritability of intelligence. Men and women now tend to look for partners who are at least as smart as they are and they tend to pass along their smarts to their children. A 2015 study reports that assortative mating correlates more with intelligence than for any other trait. The study then notes:

For example, if spouses mated randomly in relation to intelligence, highly intelligent women would be just as likely to mate with men of low as high intelligence. Offspring of the matings of women of high intelligence and men of low intelligence would generally be of average intelligence. However, because there is strong positive assortative mating, children with highly intelligent mothers are also likely to have highly intelligent fathers, and the offspring themselves are likely to be more intelligent than average. The same thing happens for less intelligent parents. In this way, assortative mating increases additive genetic variance in that the offspring differ more from the average than they would if mating were random. The increase in additive genetic variance can be substantial because its effects accumulate generation after generation until an equilibrium is reached.

Cowen concludes:

Today, we rightfully reject the idea of eugenics as repugnant, yet we are conducting our own experiments in mating, without much careful thought as to where they will lead. Match.com and Tinder help us find "just the right mate," according to our prior desires and specifications, with aid from computer algorithms. The real question may be not whether we can reverse some of the less desired effects of assortative mating, but rather just how far the practice will go.

To the extent that intelligence is correlated with socioeconomic status, assortative mating will further exacerbate trends to greater income inequality. However, future developments in genetic engineering may well provide everyone access to enhancements that will tend to decrease rather than increase any socioeconomic inequalities that associated with genetic variations.

NEXT: Freedom and hypocrisy

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  1. What do you know? Turns out accomplished, intelligent, driven people aren’t too interested in lazy loser high-school dropouts.

    Thanks science!!

    1. But income equality doesn’t care if your spouse doesn’t make you happy!

      THE STATE MUST TELL YOU WHO TO MARRY TO END INCOME EQUALITY!

    2. Not sure, but it makes nature’s case for Tony beng gay.

  2. The people who most relentlessly mock creationists who deny evolution (who do deserve most of it) are often the same people that willfully ignore and outright oppose any signs of evolution and genetic differences in humans.

    1. That observation is spot-on, and made frequently here.

  3. Today, we rightfully reject the idea of eugenics as repugnant, yet we are conducting our own experiments in mating, without much careful thought as to where they will lead.

    Jesus Christ. We clearly need a government Dating Czar to oversee peoples’ dating habits.

    1. I’ve known people in the P.C. crowd who would apply for that position. I’ve heard plenty of yammering about what preferences in a mate people (and, as always, “people” means “other people”) should not have.

      1. My criteria are valid, but yours are shallow, especially when used to reject me.

        1. ^This. Also possibly racist. Yes, it is now considered racist to only like, say, gingers.

          1. Definitely racist. Once, I explained how anything you could conceivably do was racist. Not only was I never called on it, but also, someone congratulated me on my perceptiveness.

          2. This feels awfully specific…

      2. I’d be happy if people could just pick a mate and stick to it. Instead, sometimes it seems like we’re heading back to how it was in the early part of the twentieth century, when married people felt obliged to arsk themselves every few hours, “Does this call for a divorce?”

    2. BTW, I’m calling bullshit on the claim “eugenics” is repugnant.
      “Eugenics” as a function of a coercive government is certainly so; if the same is applied to individual choice, only some slimy statist would find that repugnant.

      1. Yeah, I think that is more likely Cowen’s point.

    3. we are conducting our own experiments in mating

      No, we aren’t. At all. Each of us is marrying who we want. That’s not an experiment by any definition.

      1. It’s a natural experiment.

        1. Except when those filthy homos are involved, then we’re bringing down the republic.

          1. …and engaging in unnatural acts.

            1. Well, if a hedonistic catamite-chaser like Tonio agrees….

              1. I thought the whole point of catamites is that you don’t HAVE to chase them.

                1. “And drug him well, I don’t feel like wrestling”…?

      2. You don’t understand, Dean. Unless Top Men are in charge, it’s experimental. With experimental defined as chaotic.

    4. Say no to Genetically Modified Humans.

    5. “We clearly need a government Dating Czar to oversee peoples’ dating habits.”

      Yeah since the only purpose of our existence is to be resource units for the state, we must willingly have every aspect of our lives engineered to further the state’s objectives.

      The state’s objectives being unilaterally defined by our (self proclaimed) betters who quite naturally exempt themselves from what they would impose on everyone else.

  4. it is the white devils’ fault

    1. Also that of capitalism.

  5. It would be interesting to chart the growth of the welfare state, where we pay people to remain ‘poor’ with the widening ‘income gap’. I’m also curious as to whether the income of the ‘poor’ includes welfare in cash or in kind.
    I can easily theorize a causation…

    1. Surely you’re not suggesting that progressive policies would/could increase income inequality. That’s just crazy talk. After all, they intend to increase the roles of the “middle class” by increasing the incomes of the “lower class”. Raising the minimum wage by 50% should decrease income inequality. Everybody will be “middle class” in a few years.

      1. by hatchet, axe, and saw

  6. I find that “conclusion” distinctly creepy — “conducting our own experiments in mating, without much careful thought as to where they will lead” clearly considers human liberty and autonomy as “bugs” and obstacles to the great egalitarian agenda.

    1. As do the rest of us, and possibly many people outside the libertysphere. They really don’t realize how creepy they sound. Hopefully that will be their undoing.

      1. Cowen is in the libertysphere. I find it far more telling that people assume he thinks these “experiments” are bad.

        1. Nicole, you don’t get it. If someone mentions an undesirable phenomenon and proposes a cause, we have to assume they want to ban that cause.

          1. You’re not my mom, Carl! You can’t make me!

        2. Cowen’s B.S. free speech increases racism private gun ownership increases military interventionism implies endorsement of anti-liberty public policy.

  7. I wonder how this holds up as college attendance has grown. Now, after all, you have a (much?) wider range of socio-economic potential mates at college than you did a generation or two ago. College attendance per se might be less of a sorting mechanism than it used to be.

    I’m not sure, either, how socio-economic mobility plays into this. My father grew up in a barrio, dirt-poor. My mother was barely lower middle class, growing up with a then-rare single mother pretty much supporting the household. When I went to college, they were solidly upper-middle-class, and I was raised throughout their ascent, going from living in a two-bedroom shotgun house with no central air, to a very comfortable 4 bedroom house with all the amenities. From an assortative-mating perspective, what was I?

    Anecdote: My first wife, who I met in college was very solidly upper-middle class at a minimum (father was a DuPont exec, and she grew up with actual DuPonts as friends). To be fair, when we first got together I was on my way to law school, so I was probably a good assortative “fit” from her perspective. I never gave a crap about her family background or economics, personally.

    1. When I went to college, they were solidly upper-middle-class, and I was raised throughout their ascent, going from living in a two-bedroom shotgun house with no central air, to a very comfortable 4 bedroom house with all the amenities. From an assortative-mating perspective, what was I?

      Aren’t you old enough that no one thinks your parents did this? The idea is that you probably mated this way.

      1. You mean, no one would have thought in the ’80s that my parents were upwardly mobile? That I was always upper middle class?

        I have no idea. I doubt anyone at my school (which was a small liberal arts school that drew from a pretty narrow upperish-middle-class pool) gave it any thought. i’m wondering – is assortative mating supposed to be conscious (that is, “gold-digging”), or unconscious attraction to people “like” you?

        I do know that, as I went through law school and my early career, that I had any number of “markers” that tagged me as not-really-upper-middle-class. That’s what I was getting at with my question.

        1. You mean, no one would have thought in the ’80s that my parents were upwardly mobile? That I was always upper middle class?

          No…this isn’t really about upward mobility. It sounds like your parents were upwardly mobile, from your story, of course. But the assortative mating stuff is about intergenerational changes, so it would affect your kids, if you have any.

          i’m wondering – is assortative mating supposed to be conscious (that is, “gold-digging”), or unconscious attraction to people “like” you?

          I think a combination of conscious and unconscious attraction to people like you. If you are gold-digging, you are not mating with someone who is like you, i.e., you are not doing assortative mating. Gold-digging is basically the exact opposite phenomenon.

          I do know that, as I went through law school and my early career, that I had any number of “markers” that tagged me as not-really-upper-middle-class. That’s what I was getting at with my question.

          Yeah, that’s different, and that’s really just a story of upward mobility.

        2. is assortative mating supposed to be conscious (that is, “gold-digging”), or unconscious attraction to people “like” you?

          The latter.

          1. But assortive mating isn’t gold-digging, it’s peer-seeking. Gold-digging is a marriage between people of unequal economic statuses, most typically a poor woman “marrying money.” When you stick to your own SES you don’t have to worry about your in-laws being embarrassing yokels, or worry that your own people won’t use the proper fork.

            1. You seem to have mixed up your formers and your latters, Tonio.

            2. So people of lower economic status tend to be “yokels” and ignorant clods without knowledge of proper dining etiquette? Interesting stereotype.

        3. Interesting. Which brings me back to my first question:

          When college drew from a much narrower base, it would seem to have supported much tighter assortative mating. Everyone you met at college was “like you”.

          Now that it draws from a much broader base, it seems that it would be less of a vehicle for assortative mating, doesn’t it? The people you meet at college are not, in general, much more “like you” than people in high school or just out and about.

          1. Now that it draws from a much broader base, it seems that it would be less of a vehicle for assortative mating, doesn’t it? The people you meet at college are not, in general, much more “like you” than people in high school or just out and about.

            From an individual perspective, sure. I’d wager that statistically, you’d find of those who married someone they met in college they would possess more similarities in various traits than would be predicted if they were stochastically paired with someone from the total population of students on campus.

            1. Oh, I think you’re right about that. But I still think you’re doing better with a random co-student than out in the world.

          2. The people you meet at college are not, in general, much more “like you” than people in high school or just out and about.

            They still are, though. They may be less tightly alike than they were before, but they are still more assortative than being out in genpop. Especially when you consider that not everyone is just out at “college”; they’re all attending specific schools.

            Plus, you’ve now allowed all those people who wouldn’t have gone to college before to participate in the sorting, when before they were all out in genpop.

            I mean, I get what you’re saying, I just think the effect of (some) colleges being (somewhat) less selective are swamped by the other side.

            1. They still are, though. They may be less tightly alike than they were before, but they are still more assortative than being out in genpop

              Not to mention that class differences don’t dissolve on campus. Students still travel in cliques.

              1. Fo sho. But seriously there’s no question in my mind that this has increased with broader college attendance. If I hadn’t gone to college…things would be way different on that front.

        4. any number of “markers”

          -saying “beer” and meaning Bud Light
          -vacationing in Virginia Beach
          -preferring Hanna Barbera over Disney
          -cooking steak well done, eating it with ketchup
          -fancy pickup truck with a spoiler that renders the bed unusable

          1. Think more “Texas”:

            -pickup truck with stocked gun rack
            -etc.

          2. I still vividly remember one conversation with a classmate at Cornell who casually mentioned she was thinking about asking her dad to buy an aerospace company so she could get a defense position located inside the US (and my immediate need to get somewhere more comfortable, like a bar with $1 drafts).

            1. Wise move, Auric.

              As my dad told me, “The only problem with marrying money is that sooner or later you wind up earning it.”

              1. It wasn’t even a strategic decision. I have just never felt so out of place as that moment. Not only could her dad afford to have spent that kind of money, but apparently he could do so so easily that she didn’t even think it was a noteworthy request.

                1. Meanwhile, I was living almost exclusively on $2 microwaveable meals and free pizza scavenged from any info session I could find.

    2. I know from my experience with online dating that it is a very high percentage of college-educated women who refuse to date a man who didn’t go to college (fortunately for me, I did and am also not short which is another instant fail).

      On the flip side, any potential date who wasn’t a graduate (or maybe a senior) had to be super hot to get a date… and I wasn’t interested in anything longterm.

  8. Back in 1960 highly successful and educated men were not likely to encounter many peers of the opposite sex because not that many women went to college. So let me restate this: If women were going to college at the rate that they were 55 years ago, there would be less inequality!

    1. Blame feminism.

  9. To the extent that intelligence is correlated with socioeconomic status, assortative mating will further exacerbate trends to greater income inequality.

    Charles Murray said it first.

    1. Thank you I came to post exactly this. I’m no lover of Charles Murray but he did all the leg work on this argument in The Bell Curve and took all the heat. This article needs to credit Murray or GTFO.

      1. He really made the point clear in Coming Apart.

        1. Way late, but Murray did make this exact point in Coming Apart.

  10. Income inequality in the United States has been rising. Various explanations have been proposed ranging from the hollowing out of the middle class as middle-skilled jobs are automated away to tax policies that favor the already rich.

    The real reason which has always been the reason everywhere and in all time is that the inflationary policies of central banks undermine people savings except for the very rich, who are able to protect their assets better than the average Joe. This was true in Latin American countries, in post-war Europe, in ALL places on the fucking Earth but somehow that explanation is almost never posited by most American scholars and ‘economists’. Nah, must be because people marry other people they feel comfortable with.

    1. This, plus an economy that is increasingly capital-based, I believe, will lead to rich people being even richer on a relative basis. Once you get a capital base that you invest semi-competently, compounding means you will get richer at a faster rate than someone whose income is based solely on their labor.

  11. In 1960 few people had a chance at a college degree. Therefore, high school was the place that most people meet potential mates, people also married younger. High school was the place.

    Nowadays, more people go to college, or at least start. Most couples are waiting longer to marry. These two differences make colleges, offices, factory floors, and bars the venues of coupling. There are more choices for finding a mate, and that allows for increased self selection. One finds a mate where one looks. Why is this a bad thing?

  12. at my job we’re not allow to couple on the factory floor.

  13. So, all those stories we’ve been reading about college-educated women seeking only college-educated men “at least as smart as they are” is contributing to income inequality? Is there a correlation between income inequality and women gaining bachelors and higher degrees?

  14. I had a girlfriend in college and briefly after who was the first in her family to attend. She was from a blue collar Italian/Polish family where her dad worked in a factory and mom was a checkout clerk in a grocery store. She had a list of issues a mile long that I won’t go into, but part of the reason we spilt was that she kept asking why wasn’t I buying her expensive gifts (since my family had way more money than hers…). She was great in bed though!

    1. Sounds like “gold digger”, not “assortative”.

    2. The rule still holds. You dated only the family member who made it to college. Not her sisters or cousins.

      People now marry mates on similar paths. Less mixing of workers and slackers.

      Who is going to support the slackers if they can’t marry a worker?

  15. “future developments in genetic engineering may well provide everyone access to enhancements that will tend to decrease rather than increase any socioeconomic inequalities that associated with genetic variations.”

    It’s more likely that future genetic engineering developments will be affordable only for the rich, and will increase rather than decrease inequality.

    1. Z: From my article, “The Case for Enhancing People“:

      The enhancements that are likely to be available in the relatively near term to people now living will be pharmacological ? pills and shots to increase strength, lighten moods, and improve memory. Consequently, such interventions could be distributed to nearly everyone who wanted them. Later in this century, when safe genetic engineering becomes possible, it will likely be deployed gradually and will enable parents to give their children beneficial genes for improved health and intelligence that other children already get naturally. Thus, safe genetic engineering in the long run is more likely to ameliorate than to exacerbate human inequality.

    2. It’s more likely that future genetic engineering developments will be affordable only for the rich, and will increase rather than decrease inequality.

      If the device or procedure has practical utility, then “the rich” consuming it fronts the development cost and drives the unit price downward, opening it up to everybody else. And if it doesn’t have practical utility, then who cares?

    3. Market understanding fail in Aisle 409. Mr. Moore, cleanup on 409 please.

  16. “Men and women now tend to look for partners who are at least as smart as they are and they tend to pass along their smarts to their children.”

    I don’t know that I agree that it’s about intelligence and it’s heritability…Are they seeking out those as smart as they are or as credentialed as they are? There is a difference.

    Moreover, do those parents “pass along their smarts” or do they simply teach their children discipline, self control and the ability to delay gratification? Anyone who masters those skills can go a long way in the world with average intelligence…

    1. Are they seeking out those as smart as they are or as credentialed as they are? There is a difference.

      There is a difference, but using the credential as a proxy is still better than what they were doing before, as far as effectiveness in finding people with an actual intelligence match.

      And it’s not just about the credential. It’s about being in a milieu full of people with the credential, and selecting among that group for someone similar to yourself.

      Moreover, do those parents “pass along their smarts” or do they simply teach their children discipline, self control and the ability to delay gratification?

      Research suggests that intelligence is heritable.

      1. I agree that it is heritable however I am wondering if it is a non-factor in this case. Is it about inherited intelligence or is it about having parents that teach you the proper skills. You can have a wildly intelligent child born of lower class parents but if those parents aren’t raising their children to possess discipline and self control then that intelligence is for naught as that child will wind up not working hard in school or always getting into fights when he doesn’t get his way or knocking up the first girl he sleeps with because he has no self-control…that is what I am genuinely curious about.

        Put another way is it nature or nurture?

        1. Phenotype = Genotype + Environment

      2. Research suggests that intelligence is heritable.

        I’m genuinely curious: does the research control for being raised by intelligent parents? Being someone’s kid means you get both nature and nurture, if you are raised by them.

        How did they control for the nurture of being raised by intelligent parents? Did they track kids who were raised by other parents of different intelligence, and find that the kid’s intelligence tracked their biological parents, not the people who raised them?

        I’m a compulsive reader, and I think its because my mother was a compulsive reader (“I learned it from you, ma!”)

  17. Don’t worry. This all gets sorted out in the future. See idiocracy.

  18. Isn’t this what Hernstein & Murray already said? Or did they not have the data, & now it’s there?

    1. As I noted earlier, this isn’t news.

  19. Lots of talk about the problem, but few suggestions on how to fix it.

    Let me suggest the following:

    -Really intelligent men should be paired off with hot cocktail waitresses – wait, they’re more or less doing a TV series about that already.

    -Intelligent women should lower their standards to the absolute rock bottom. Hello, ladies!

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