Is Poverty in Our Genes? is the title of a new extended critique of Ashraf and Galor’s forthcoming American Economic Review paper on genetic diversity and economic development. Published in Current Anthropology, the critique is an extension of an earlier piece by a group of academics (mainly from Harvard) who argue that Ashraf and Galor’s work is false and undesirable.
The critique spends some time focusing on the data underlying Ashraf and Galor’s work, which provides a good reminder of the complexity of human migratory history. For example, the authors write:
Historical flaws also exist in Ashraf and Galor’s treatment of concepts of innovation in table A3. Here the achievements of the diverse populations at Cordoba are taken to stand for measures of “European” innovation at 1000 CE. It is misleading to use Cordoba as a measure of European success, given that it was ruled by North African Moors until 1236 CE. Likewise, it seems inconsistent to classify Constantinople as part of Europe in 1000 CE but part of Asia in 1500 CE (Ashraf and Galor 2013, table A3). It should also be remembered that Europe’s role in innovation is a very recent phenomenon. Indeed, if we are to look for traces of “innovation” according to Ashraf and Galor’s standards in Europe, archaeology has made it clear that agriculture was not independently invented in Europe, but rather spread there from the Near East (Bellwood 2006). One can also show that Renaissance Europe was heavily influenced by Greek and Arab thought (Lewis 2009; Saliba 2007). Clearly, there is a great deal of multicontinental interaction in the circum-Mediterranean region. If one excluded these data coming from the heavily African- and Middle Eastern–influenced Mediterranean region, population levels (and hence innovation levels, according to Ashraf and Galor) in Europe would be low compared to other areas of the world until the late medieval period (after 1470).
These are interesting arguments, but I’m not convinced that shifting a few data points will materially change the general findings. The more fruitful area of criticism is the causative mechanism. In that area, the authors make some interesting points about evidence from other species.
Ashraf and Galor’s theoretical model argues that genetic diversity can play a positive role in the expansion of a society’s “production possibility frontier” or its ability to innovate. In their appendix H, they use animal studies to justify this claim. They describe studies on insects that link genetic diversity to disease resistance and to several aspects of hive performance in honeybees (Seeley and Tarpy 2007; Tarpy 2003). The two bee studies cited by Ashraf and Galor correlate genetic diversity with bee foraging rates and hive temperature and indicate that disease susceptibility relates to inbreeding. Another cited insect study on fruit flies (Drosphila species) shows that genetic diversity helps increase resistance to environmental changes (Frankham et al. 1999). It is unclear how either of these relates to an ability to innovate. Perhaps Ashraf and Galor were inspired to use these data because there is no research demonstrating that genetic heterozygosity at the population level is associated with capacity to innovate.
In addition, these cross-species comparisons of genetic diversity seem to not take into account how genetic diversity varies widely among species. Humans are noted for having extremely low levels of genetic diversity compared to other animals, including our closest cousins, chimpanzees. In fact, some chimpanzee breeding groups, such as those in the Taï forests of West Africa, are estimated to have greater nucleotide diversity than the entire human species (Gagneux et al. 1999). It is important to put into perspective that the total amount of human genetic diversity is actually quite small compared to that found in other model organisms.
My posts on Ashraf and Galor’s paper on genetic diversity and economic growth are as follows:
- A summary of the paper methodology and findings
- Does genetic diversity increase innovation?
- Does genetic diversity increase conflict?
- Is genetic diversity a proxy for phenotypic diversity?
- Is population density a good measure of technological progress?
- What are the policy implications of the effects of genetic diversity on economic development?
- Should this paper have been published?