Out of Africa, Diversity, and Development

Quamrul Ashraf and Oded Galor have found (pdf) a humplike correlation between the genetic diversity of populations and their levels of economic development.

They measure genetic diversity by the distance from out-of-Africa human migration: population bottlenecks mean that genetic diversity is high in East Africa, medium in Eurasia, and low in the Americas. (All this is before more recent migrations.) High and low diversity (Africa, Americas) is associated with less development than the medium or Goldilocks just-right level (Eurasia).

What’s the mechanism?

I don’t know and nor do the authors. But they do make a tentative suggestion:

The benefits of genetic diversity … in the Darwinian theory of evolution by natural selection … increases the adaptability and, hence, the survivability of a population to changing environmental conditions.

Well, yes, variation is needed for selection. But its a very, very long way from there to economic development.

On the other hand, to the extent that genetic diversity is associated with a lower average degree of relatedness amongst individuals in a population, kin selection theory, which emphasizes that cooperation amongst genetically related individuals can indeed be collectively beneficial as it ultimately facilitates the propagation of shared genes to the next generation, is suggestive of the hypothesized mechanism through which diversity confers costs on aggregate productivity.

Also, an intriguing idea, that homogeneity increases cooperation which aids development. But it also seems to be a long way from really nailing down what the mechanism may be.

Quamrul Ashraf and Oded Galor, “The Out of Africa Hypothesis, Human Genetic Diversity, and Comparative Economic DevelopmentAmerican Economic Review forthcoming.



Filed under economic evolution, genetic history

3 responses to “Out of Africa, Diversity, and Development

  1. Pingback: Anthropologists as Libel Lawyers | Breviosity

  2. There’s a good candidate for a potential confounding variable here: ability to communicate/trade with the rest of the ‘old world web’ (McNeill & McNeill). The largest part of humanity lives in Eurasia. The Sahara is a barrier to communication/trade with the rest of the world-island, the Bering Strait an even greater barrier. Less communications and trade results in lower socio-economic development. These geographic bottlenecks are also (uncontroversially) responsible for levels of genetic diversity amongst populations.

    The paper does examine geographical proximity to regional technological frontiers/economic hubs, but not to global frontiers/hubs.

    • Agreed. Jared Diamond had a version of the idea that diffusion was easier in Eurasia.
      But according to one paper, geog isolation had a *positive* effect on econ dev: Ashraf, Q, O. Galor, and Ö. Özak (2010) “Isolation and Development” Journal of the European Economic Association 8(2-3), 401-412
      Maybe there is some other confounding variable too.

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