The monkey-cage: Why is Africa poorer than the rest of the world?

[JFK wabongo]

Monkey Cage

 

[JFK wabongo]

Kuna maswali mengi kuliko majibu...
Wazungu wametugeuza subject za research zao.

 

[JFK wabongo]

A few years ago, two economics professors, Quamrul Ashraf and Oded Galor, published a paper, “The ‘Out of Africa’ Hypothesis, Human Genetic Diversity, and Comparative Economic Development,” that drew inferences about poverty and genetics based on a statistical pattern.

The world’s most genetically diverse countries (using their measure of what counts as genetically diverse) are in sub-Saharan Africa, which is the world’s poorest region. The least genetically diverse countries are in places such as Bolivia, which have low incomes, but not as low as in that region of Africa. There’s an intermediate level of genetic diversity among the residents of the middle-income and rich countries in Asia, Europe and North America.

Genetic diversity arises from the migratory distance of populations from East Africa. Countries in East Africa have the highest genetic diversity because that is where humans evolved. Populations that settled in other parts of the world descend from various subgroups of people who left Africa at different times. Thus, these groups are less varied in their genetic profiles.

Ashraf and Galor put this together and argued that this is “reflecting the trade-off between the beneficial and the detrimental effects of diversity on productivity.” Their argument was that a little bit of genetic diversity is a good thing because “a wider spectrum of traits is more likely to be complementary to the development and successful implementation of advanced technological paradigms,” but if a country is too genetically diverse, its economy will suffer from “reduced cooperation and efficiency.” Thus, they wrote, “the high degree of diversity among African populations and the low degree of diversity among Native American populations have been a detrimental force in the development of those regions.”

Any claim that economic outcomes can be explained by genes will be immediately controversial. It can be interpreted as a justification of the status quo, as if it is arguing that existing economic inequality among countries has a natural, genetic cause. See this paper by Guedes et al. for further discussion of this point.

When the paper by Ashraf and Galor came out, I criticized it from a statistical perspective, questioning what I considered its overreach in making counterfactual causal claims such as:

… increasing the diversity of the most homogenous country in the sample (Bolivia) by 1 percentage point would raise its income per capita in the year 2000 CE by 41 percent, (ii) decreasing the diversity of the most diverse country in the sample (Ethiopia) by 1 percentage point would raise its income per capita by 21 percent.

I argued (and continue to believe) that the problems in that paper reflect a more general issue in social science: There is an incentive to make strong and dramatic claims to get published in a top journal.