Like modestly attracts like

By Razib Khan | September 26, 2011 12:04 am

I saw this link posted on twitter, IQ and Human Intelligence:

An interesting finding from genetic research, which Mackintosh mentions, only in passing, as posing a problem in the estimation of the heritability of g, is that there is greater assortative mating for g than for any other behavioral trait; that is, spouse correlations are only ∼.1 for personality and only ∼.2 for height or weight, but the correlation for assortative mating for g is ∼.4. In addition to indicating that people are able to make judgments about g in real life, this finding suggests that assortative mating may contribute to the substantial additive genetic variance for g, because positive assortative mating for a character can increase its additive genetic variance.

I’ve seen these sort of results before. The review is from 1999. In general I always wonder if quantitative values for personality are not to be trusted because of issues with the measurement of personality types. But this is clearly not an issue with height or weight. And in the case of height the overwhelming causal explanation for variation in the West is genetic variation. Overall I’m rather surprised by the rather low correlations for some of these traits, such as height and intelligence. I wonder if beauty, perhaps measured by an index of facial symmetry, might exhibit higher correlation values?

MORE ABOUT: I.Q., marriage, Sociology

Comments (7)

  1. Grey

    In terms of social heirarchy there’s actually two heirarchies, blue-collar and white-collar, one on top of the other. The people at the top of the blue-collar heirarchy i.e electrician level, have been assortatively mating on g since forever.

  2. AG

    The findings make sense to me as observation in real life. If our ancestors did this for millions years, sexual selection might contribute great deal to the evolution of human intelligence.

    Hope it continue.

  3. Darkseid

    ah, so people really DO value intelligence like they say in their dating profiles but the detail is that they prefer intelligence similar to their own level? i always assumed they were lying and only cared about money or looks but i guess, technically, they are speaking their own (relative) truth at least some of the time.

  4. ben g

    Attractiveness might be the only thing with a higher correlation in mates than intelligence. Make a model where you combine attractiveness and intelligence and I think you could explain most variation in mating.

  5. Miguel Madeira

    “In addition to indicating that people are able to make judgments about g in real life”

    Does not necessarly means that – could simply mean that people with very different g have difficulty in interaction together

  6. RafeK

    I am curious if their are strong correlations for some asymetric traits that like male height or intelligence with female beauty.

  7. ackbark

    In ordinary social circumstances intelligence and personality flow together pretty seamlessly.

    How do you in practice separate the two?


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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at


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