Tuesday 15 March 2016

Admixture in the Americas: European intelligence


John Fuerst and Emil Kirkegaard have been looking at some interesting data sets, and coming to interesting and succinct conclusion, with all their workings openly available for further testing.

John Fuerst and Emil Kirkegaard. Admixture in the Americas: Regional and National Differences. MANKIND QUARTERLY 2016 56:3 256


There are also 6 critical comment for readers to look at.

We conducted novel analyses regarding the association between continental racial ancestry, cognitive ability and socioeconomic outcomes across 6 datasets: states of Mexico, States of the United States, states of Brazil, departments of Colombia, sovereign nations and all units together. We find that European ancestry is consistently and usually strongly positively correlated with cognitive ability and socioeconomic outcomes (mean r for cognitive ability = .708; for socioeconomic well-being = .643) (Sections 3-8). In most cases, including another ancestry component, in addition to European ancestry, did not increase predictive power (Section 9). At the national level, the association between European ancestry and outcomes was robust to controls for natural-environmental factors (Section 10). This was not always the case at the regional level (Section 18). It was found that genetic distance did not have predictive power independent of European ancestry (Section 10). Automatic modelling using best subset selection and lasso regression agreed in most cases that European ancestry was a non-redundant predictor (Section 11). Results were robust across 4 different ways of weighting the analyses (Section 12). It was found that the effect of European ancestry on socioeconomic outcomes was mostly mediated by cognitive ability (Section 13). We failed to find evidence of international colorism or culturalism (I.e., neither skin reflectance nor self-reported race/ethnicity showed incremental predictive ability once genomic ancestry had been taken into account) (Section 14). The association between European ancestry and cognitive outcomes was robust across a number of alternative measures of cognitive ability (Section 15). It was found that the general socioeconomic factor was not structurally different in the American sample as compared to the worldwide sample, thus justifying the use of that measure. Using Jensen's method of correlated vectors, it was found that the association between European ancestry and socioeconomic outcomes was stronger on more S factor loaded outcomes, r = .75 (Section 16). There was some evidence that tourist expenditure helped explain the relatively high socioeconomic performance of Caribbean states (Section 17).

This paper is long, very detailed and content rich, and important. It follows the new and noble practice of showing all its workings, so the diligent reader can test the findings, and in that same spirit of openness includes critical opinions from other scholars: research as it ought to be.

12 zero-order correlational analyses found a substantial positive relationship of European ancestry with both cognitive ability and general socioeconomic well- being. Multiple regression results generally found that European ancestry remained a non-redundant positive predictor when including natural- environmental predictors in the models. Socioeconomic (S factor) scores in the United States were the sole exception. More research is needed on the relationship between socioeconomic outcomes and racial ancestry in that country.

Our path analysis and semi-partial analyses indicated that cognitive ability scores can largely statistically explain the association between ancestry and socioeconomic outcomes.

The association between racial ancestry and outcomes could be mediated by genetic, cultural or other factors (Rindermann, 2015). As it has been demonstrated that indices of genetic ancestry track an array of inter- generationally transmitted cultural traits (Spolaore & Wacziarg, 2015), the results are consistent with a cultural mediation model. While the association between racial ancestry and outcomes is also consistent with an evolutionary genetic model, to obtain decisive evidence in support of such a model, one would need to identify specific alleles that vary between ancestral groups which are directly (e.g., Piffer, 2015b) or (plausibly) indirectly (e.g., Fedderke et al., 2014) associated with cognitive and/or socioeconomic outcomes at the individual level (Rindermann, 2015).

Based on a review of dozens of studies, Fuerst and Kirkegaard (2015) found that racial ancestry was associated with inter-individual socioeconomic outcome differences within admixed populations (e.g., Black Trinidadian and Toboggans) throughout the Americas (e.g., in Brazil, Chile, Colombia, Mexico, Peru, Puerto Rico, Trinidad and Tobago and the United States). Across studies, African and Amerindian ancestry was negatively and European ancestry was positively associated with socioeconomic outcomes. It is an open question, however, as to whether, on this same level of analysis, cognitive ability is robustly associated with racial ancestry and as to whether cognitive ability mediates the biogeographic ancestry-socioeconomic outcome association. There are, at present, a number of datasets which allow for the testing of these hypothesis, such as the US based Pediatric Imaging, Neurocognition and Genetics (PING) survey and The National Longitudinal Study of Adolescent to Adult Health (Add Health) survey.

As for limitations, we wish to emphasize that our national level cognitive measures were suboptimal. Our intra-national level indexes of ancestry were often likewise. Also, measurement error can give problems with multiple regression type approaches resulting in false positives (Westfall & Yarkoni, under review), and it is unknown how measurement error and the SAC measure and control methods interact. We suspect that better measures will not substantively alter the results, as they generally were robust across different analyses and different measures. Nonetheless, replicating the analyses using better and more fine- grained measures would be worthwhile.

The conclusion the authors come to is that to understand the intelligence and social achievements of people in the United States of America, Mexico, Brazil and Colombia you need to know only one thing: how much European ancestry they have. This is pretty much a consistent finding in their samples, but they look through many other possible explanations, such as the contributions of other genetic groups, the special contribution of tourism to economies, and the depredations of other factors like parasite load, all covered in detail in their paper.

Here are the pictures for each of the states or provinces, and then the composite picture.

European ancestry and Mexican states

European ancestry and US states

European ancestry and Brazilian state

European ancestry and Colombian departments

European ancestry and nations

Above is the picture for sovereign nations.


European ancestry, states and nations combined


So, that’s the Americas sorted out. With the partial exception of US states, to the extent that they are European, they are bright and successful.


  1. This comment has been removed by the author.


  2. http://drjamesthompson.blogspot.co.uk/2015/09/bright-folk-do-community-stuff.html

  3. Francisco, here is a review of that economist's latest book

  4. Thank you, Mr Thompson, and my apologies for the mistake.

  5. I am happy to find your way of writing the post. Now you make it easy for me to understand and implement the concept. Thank you for the post.
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  6. I've often wondered about the contrast between (i) the Incas, Aztecs, and their predecessors being capable of building and running advanced empires, and (ii) their descendants doing badly on tests of, or inferences about, cognitive skills. I wonder whether the huge death rates from Old World diseases during and after the conquests were somehow selective against IQ. I don't know enough biology to begin to suggest a mechanism for that.

  7. Interesting question. It is usually the case that elites survive better. It would fit in with current findings on system integrity, that bodily health and a good brain share common common genetic pathways, and are more resistant to wear. So, it would be more likely that that brightest survived. How advanced were those civilisations? The Incas had some blind spots. China they weren't. No answer at the moment.

  8. Yeah, but unlike China they hadn't had the chance to learn from any other civilisation. It was all the Amerindians own work.

    What if it was simple? The cleverclogs lived at high population density in cities and towns, and died at horribly high rates. The yokels, living at low population densities, were less vulnerable to the brand new infections.

  9. Why doesn't someone do genetic testing on people to determine their amount of Eureopean ancestry and test their IQ. Wouldn't that solve the race/IQ controversy once and for all?

    -Steve Jackson

    1. Given large sample sizes, it could resolve the matter, but no one will fund or allow such research, fearing that a significant genetic component would be revealed, and being terrified of that result.

    2. How large would the sample have to be?

      Have you ever met an environmentalist who told you that the, say, Jewish IQ and high level of achievements (1/3 of the Noble prizes in hard sciences) has no genetic component?


    3. "How large would the sample have to be?"
      Steve Hsu says about 1,000,000 full genomes should allow identifying most of the IQ-affecting alleles.
      " I estimate the statistical power required to characterize both linear and nonlinear models for quantitative traits. [...] The required sample size is of order 100s, or roughly a million in the case of cognitive ability."

      IIRC that estimate was revised to about 300,000 using fancy compressed-sensing techniques. Full genomes may not be needed to get most of that.

      To identify ancestry, looking at only a few dozen of the right genes can determine actual ancestry better than genealogical records. A sample size of a few thousand with standardized test scores would be good enough for practical purposes, but really no amount of evidence will convince those who are not already convinced by data sets such as the NLSY which cover over a million people over decades. H&M's The Bell Curve really closed off all plausible objections to the gene-intelligence link both within and between populations, but the blank-slatists and diversity cheerleaders just closed their eyes, stuck their fingers in their ears and went: "Na na na ... I can't hear you! Heretic! Meanie!" and so forth in that vein.

    4. Steve Hsu says 1 million required, but also added in an exchange of views we had "but I may be wrong". A large sample is certainly needed to get round false positives. Yes, many commentators dislike contrary results (in all directions).

  10. Nice paper; I would buy them a drink.