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Family values matters in education

Genetic and environmental variation in educational attainment: an individual-based analysis of 28 twin cohorts:

We investigated the heritability of educational attainment and how it differed between birth cohorts and cultural–geographic regions. A classical twin design was applied to pooled data from 28 cohorts representing 16 countries and including 193,518 twins with information on educational attainment at 25 years of age or older. Genetic factors explained the major part of individual differences in educational attainment (heritability: a2 = 0.43; 0.41–0.44), but also environmental variation shared by co-twins was substantial (c2 = 0.31; 0.30–0.33). The proportions of educational variation explained by genetic and shared environmental factors did not differ between Europe, North America and Australia, and East Asia. When restricted to twins 30 years or older to confirm finalized education, the heritability was higher in the older cohorts born in 1900–1949 (a2 = 0.44; 0.41–0.46) than in the later cohorts born in 1950–1989 (a2 = 0.38; 0.36–0.40), with a corresponding lower influence of common environmental factors (c2 = 0.31; 0.29–0.33 and c2 = 0.34; 0.32–0.36, respectively). In conclusion, both genetic and environmental factors shared by co-twins have an important influence on individual differences in educational attainment. The effect of genetic factors on educational attainment has decreased from the cohorts born before to those born after the 1950s.

One of the stylized facts of behavior genetics that isn’t well known to the public is that “shared environment” doesn’t matter that much. By this, I mean shared home environment. This was the major thesis of Judith Rich Harris’ The Nurture Assumption. So what’s going on with this result? The shared environment does seem to matter for educational attainment!

First, I want to touch on how these sorts of results might be interpreted. On Twitter some have suggested that a low shared environment fraction is promoted by hereditarians to emphasize how we can’t change things in regards to the status quo. My first thought was fear that competitive investment in children does return positive yields, and how much more as a parent will I have to invest???

The point is that a particular empirical result has a lot of different conclusions for a lot of different people. It’s not as predictable as you might think.

But in regards to this result, I asked a friend who is a behavior geneticist, and his response calmed me. Basically educational attainment is an output that naturally has a lot of family inputs. Far more than raw IQ. For example, families may know how the college application process works, and how to write the essay, and which extracurriculars to do. Additionally, it’s pretty obvious difference families emphasize education differently, and this is going to matter for students on the margin. I know many people of the same rough intelligence, the ones who went to college had particular family expectations that differed from those who did not go to college.

If you care about social egalitarianism, I think one takeaway is to enforce mandatory standardized testing to identify students who might be promising, and subsidize university for them. Standardized tests are loaded toward the well-off, but far less than all other measures.

4 thoughts on “Family values matters in education

  1. It does seem plausible that there is some effect on secondary and then university attainment, probably through some “non-IQ”/non-intelligenec pathway. Working out what the exact shared environment factors are, and whether family structure specifically has any importance at all, would a next step?

    One facet of this in paper, paper: “Our region-specific results are also against of our prior hypothesis. We expected that shared environment would be especially large in countries following the liberal model of typology by Esping-Andersen, i.e. North America and Australia in this study, leading to lower heritability, because in these countries parental economic resources may be more important for higher education than in the countries where higher education is free and organized by the government. However, this was not the case: the heritability estimates were at the same level as in the European countries including in this study countries following the social-democratic or conservative models.”

    “Social democracy” and reduced income inequality doesn’t help to offset “shared environment” effects?

    But that makes sense. We found that parental resources don’t really have much to do with pure edu attainment in the UK – generally found that private schooling at secondary level had no effect on pure edu attainment variables after prior attainment factored in. E.g. https://www.nature.com/articles/s41539-018-0019-8“once we controlled for factors involved in pupil selection, there were no significant genetic differences between school types, and the variance in exam scores at age 16 explained by school type dropped from 7% to less than 1%” . (There might be some effects on type of university/type of course/post-education income etc, but those aren’t simply these EduYears type variables). So it wouldn’t matter too much for pre-university attainment, at least by the broad measures.
    The proposal that “free college doesn’t matter for educational mobility” is also a curious one. One solution is it may be the case that, as often charged, “free college” mostly results in intensified use by exactly the same people who already have extensive household resources. This is the “Free college is simply a wealth transfer to those with high familial resources anyway” proposal. The other is that the study group was in the past US fees were pretty small in the past, so wealth effects would only matter in the present day. Finally, there’s the proposal that fees didn’t then and still don’t actually provide much of a disincentive today – despite rhetoric, they’re mostly affordable and where they’re not, people simply declare bankruptcy and get on with their lives.

  2. As for the final bolded imperative, what can “we” do? Even if you were dictator, pronouncements are not magic. Mandatory testing is a good proposal because it is simple and standardized; you can tell if it’s actually happening. You don’t have to trust the guidance councilors to identify the promising students and steer them towards testing.

    As for subsidies, don’t we already have plenty? The problem is that they are complicated and opaque and the guidance councilors act as gatekeepers. Or just don’t know. The question is how to make them more transparent. I am sure that many countries do this better than America. But the study covered these countries. Europe has tended to have a little more heritability than America/Australia, but not that much.

    ———

    One thing that is odd about the study is that the cohorts born in the 80s are much smaller than the cohorts born in the 70s. There is also a gigantic shift of variance from shared to genetic from the 70s to the 80s. It is so large and so abrupt, that it should be the headline, if it were true. I am suspicious that the small samples reflect some kind of restriction of range. It appears simultaneously in all three geographies, which is surprising whether it’s true or due to selection bias. It appears in both sexes, which is not so surprising.

  3. Speaking as a parent with 2 kids in college, one in a PHD program and the other looking at one, money is not a large obstacle in the USA. My modest, middle class salary (nurse), is sufficient to keep both kids in full time college. My kids both managed to get lots of grants and scholarships and to date have not borrowed money. None of us is brilliant, but colleges are throwing money at us. Reasonably smart kids can go to college under the current system.

  4. I think one takeaway is to enforce mandatory standardized testing to identify students

    Don’t your arms completely tire from continuously swimming upstream?

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