Personality and genes

By Razib Khan | November 11, 2011 6:10 am

There’s a variable in the GSS, GENEEXPS, which asks if genes play a role in personality. The options are:

– It’s genes which play a major role

– It’s experience which determines personality

First, let’s admit that the premise is stupid. Personality is heritable, but environmental variation also seems to matter. In other words it is noncontroversial to assert that both genes and environment can explain variation in personality (or perhaps more precisely genetic variation can only explain around half the variation for any given trait).

I was curious how this broke down by education and intelligence. To remove demographic confounds I limited the sample to non-Hispanic whites. For intelligence I used WORDSUM, with scores 0-4 being dumb, 5-7 being average, and 8-10 being smart.

Genes play major role Experience plays major role
Less than HS 33 67
High School 26 74
Junior College 26 75
Bachelor 21 79
Graduate 24 77
Dumb 25 75
Average 25 75
Smart 24 76

CATEGORIZED UNDER: Behavior Genetics
MORE ABOUT: Genes, Personality
  • Darkseid

    I remember Eric Turkheimer saying that all underlying personality characteristics are genetic.

  • Mustapha Mond

    Pretty flat results! As an example, I think we all instinctively understand that children from broken homes have greater trouble coping later in life irrespective of native intelligence (severely mentally handicapped excluded.)

    PS – I still refuse to call those with less than a perfect score on the idiotically simple WORDSUM test “smart.”

  • plutosdad

    It seems experience plays more of a role for people who’ve spent more time in learning environments, no matter how smart they are. I suppose this makes sense after all if education is to help us understand the world and ourselves better, and the higher in education we go the more we meet people unlike us, which forces us to re-examine prejudices and assumptions.

    Though i wonder why there is a larger difference between “less than HS” and “HS” rather than between “HS” and some college, maybe the years 15-18 are so formative that those few years in HS change us greatly, but people not in the school environment do not undergo that transformation. (Or there is some genetic component that drives people to drop out of HS.) I wonder if we could detect a similar difference between homeschooled kids who go to college, vs traditional schooled kids who go to college.

  • ackbark

    “I wonder if we could detect a similar difference between homeschooled kids who go to college, vs traditional schooled kids who go to college.”

    Good question. I’ll hazard the guess that it’s because those who drop out during or before high school invariably end up in some very low-end environment and with highly restricted selection of personalities and experience around them, where completing high school just exposes you longer to that wider variety.

    And part of the reason people like that drop out of high school is that they simply cannot take the information overload, and that must be largely genetic.

    So for that set of people genetics is the right answer because they couldn’t take anymore variety in experience than they’ve had.

  • Chris T

    This is a very poorly conceived and worded question; did it come from an undergrad’s research project?

  • Emma

    It does not seem so obvious to me that environmental variation influences personality. All studies on the heritability of personality seem to agree that there is almost no effect of shared environmental variation. Only non shared one has an influence, andI think it is better interpreted as noise, rather than a “real” influence of the environment.

  • Razib Khan

    #6, that’s why i said (or perhaps more precisely genetic variation can only explain around half the variation for any given trait). i was trying to head off “gotchas” like yours, while trying to remain comprehensible to people. but thanks anyway!

  • Emma

    Hey I was not trying to go “gotcha” here (especially with my rather clumsy english).

    I just meant that, In my opinion, “It’s experience which determines personality” is false and that there is no (strong) argument in favor of an influence of the environment, in the usual sense of this word, on personality.

  • Jacob Roberson

    Razib Khan: To some degree an unsurprising example of “I’ve been changed by experience so experience is what changes people” projection. But also reminds me that heritability itself (herit of g) seems to vary between populations.

  • Jorge Laris

    Graduate 24 77
    Dumb 25 75
    Average 25 75
    Smart 24 76

    I don’t see any correlation. Does that means that intelligence affects only the way we think, but not the amount of thinking?

  • DK

    It’s almost tragic. Such an important question, and the one for which pretty good evidence-based answers are available, yet a huge majority of public across all social strata is completely clueless about it.

  • e.d.

    When I was the parent of one child, I thought that environment was the controlling factor in the child’s personality. When the second child came along, I had to revise that view. Now that both are adults, they are still very different – a combination of their ancestors in looks, behaviour, habits – I can see glimpses of great grandparents who died long before they were born.


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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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