https://pmc.ncbi.nlm.nih.gov/articles/PMC4749462/

Here is a more recent meta-analysis from 2015 that concludes that the genetic additive effect on total outcomes is significant and distinct from the SES…

But only in the US.

In Europe, Australia, elsewhere, the genetic additive effect is statistically insignificant.

(IE, SES is the dominant factor)

This meta-analysis of published and unpublished data provided clear answers to our three questions.

First, studies from the United States supported a moderately sized Gene × SES interaction on intelligence and academic achievement (a′ = .074; Fig. 1).

Second, in studies conducted outside the United States (in Western Europe and Australia), the best estimate for Gene × SES magnitude was very slightly negative and not significantly different from zero.

Third, the difference in the estimated magnitude of the Gene × SES effect between the U.S. and the non-U.S. studies was itself significant.

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Fig 1, Variance vs SES, in the US

(my own commentary: the wealthier you are in the US, the more of a complete crapshoot it is whether or not you are smart or stupid… because IQ doesn’t matter for wealthy people.)

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…the cross-national difference identified does not appear to be an epiphenomenon of cross-national differences in the age ranges examined or the particular intelligence or achievement outcomes measured.

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Interestingly, as can be seen by comparing Figures 2 and S2, these Gene × Age trends closely parallel the U.S. Gene × SES effect. Genes account for considerably more variation in intelligence both at higher ages and in higher U.S. socioeconomic contexts.

Indeed, both phenomena may reflect a process of increased and accumulated effects of gene-environment transactions with the increased opportunity that comes with both social class and age (Tucker-Drob et al., 2013; Turkheimer & Horn, 2014).

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Without conducting my own entire study…

My read on this is that the genetic component is much more significant in the US than in other places…

… because the US is significantly more economically stratified, nepotistic, and has a broken education system where rich idiots can get all the education they want, and skate by, but you basically have to be a diligent and lucky genius to escape poverty and the shit-tier education it has bestowed you with.

The noted tendency of age to also be correlated with SES and genetics in the US, is again, imo, explained by our vastly broken healthcare system just literally killing you if you are either poor, or stupid.

If I am not mistaken, we are uh, still trending downward on overall life expectancy, as compared to most other developed countries in this study sample set where life expectancy either was not badly affected by COVID, or was but has since rebounded.

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But uh yeah, going back to this more recent study… looks like genes have a less meaningful impact than your SES in civilized areas of the world.

Here in the US, we only have downward class mobility, unless you are very, very clever, and continuously lucky, continuously reinvesting those gains from your cleverness into social and financial capital without making any ‘bad investments’, or ever having any sudden medical or financial disaster happen to you.

Kakistocracy: Rule by the least fit to govern, the worst qualified, the most unscrupulous.

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Anyway, not to sound like I am directing my venom here at you, I do very much appreciate you bringing an actual comprehensive meta analysis and giving a very good and well reasoned read on it, with caveats. =D