The "Out of Africa" Hypothesis, Human Genetic Diversity, and Comparative Economic Development

Abstract

This research argues that deep-rooted factors, determined tens of thousands of years ago, had a significant effect on the course of economic development from the dawn of human civilization to the contemporary era. It advances and empirically establishes the hypothesis that, in the course of the exodus of Homo sapiens out of Africa, variation in migratory distance from the cradle of humankind to various settlements across the globe affected genetic diversity and has had a long-lasting effect on the pattern of comparative economic development that is not captured by geographical, institutional, and cultural factors. In particular, the level of genetic diversity within a society is found to have a hump-shaped effect on development outcomes in both the pre-colonial and the modern era, reflecting the trade-off between the beneficial and the detrimental effects of diversity on productivity. While the intermediate level of genetic diversity prevalent among Asian and European populations has been conducive for development, 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 these regions. IntroductionExisting theories of comparative development highlight a variety of proximate and ultimate factors underlying some of the vast inequities in living standards across the globe. The importance of geographical, cultural and institutional factors, human capital formation, ethnic, linguistic, and religious fractionalization, colonialism and globalization has been at the center of a debate regarding the origins of the di¤erential timing of transitions from stagnation to growth and the remarkable transformation of the world income distribution in the last two centuries. While theoretical and empirical research has typically focused on the e¤ects of such factors in giving rise to and sustaining the Great Divergence in income per capita in the pre-industrial era, attention has recently been drawn towards some deep-rooted factors that have been argued to a¤ect the course of comparative economic development. This paper argues that deep-rooted factors, determined tens of thousands of years ago, have had a signi…cant e¤ect on the course of economic development from the dawn of human civilization to the contemporary era. It advances and empirically establishes the hypothesis that, in the course of the exodus of Homo sapiens out of Africa, variation in migratory distance from the cradle of humankind in East Africa to various settlements across the globe a¤ected genetic diversity and has had a long-lasting hump-shaped e¤ect on the pattern of comparative economic development that is not captured by geographical, institutional, and cultural factors.Consistent with the predictions of the theory, the empirical analysis …nds that the level of genetic diversity within a society has a hump-shaped e¤ect on development outcomes in the pre-colonial as well as in the modern era, re ‡ecting the trade-o¤ between the bene…cia...

The roots of ethnic diversity

“…We conduct several more tests in the working paper version of this paper (available online or on request). For instance, we test for, and can reject, spatial autocorrelation using an approach similar to that in Ashraf and Galor (2010). We also run several regressions with other indicators of ethnic diversity as dependent variables which does not change the main tendencies.…”

“…Migratory distance from Ethiopia has been shown by several scientific works to be negatively related to the degree of genetic diversity (heterozygosity) in the populations (Ramachandran et al 2005;Liu et al 2006). Ashraf and Galor (2010) is the first effort in economics that employs this methodology for assessing the predicted genetic diversity within countries. Countries far from Ethiopia were on average settled relatively late, and a correlation between Migdist and Origtime of −0.53, suggests that Migdist is an explanatory factor for the variation in Origtime.…”

“…On the other hand, more diversity should improve the creation of new technological ideas. Using data on genetic diversity (heterozygosity) within countries, Ashraf and Galor (2010) demonstrate that there appears to have been an inverted U-shaped relationship between diversity and economic performance in 1500 and 2000 CE. Our approach differs from these two in that our ultimate dependent variable is ethnic fractionalization rather than economic performance.…”

“…Using data on genetic distances between populations from CavalliSforza et al (1994), Spolaore and Wacziarg (2009) show that income convergence appears to be faster among genetically "close" countries and peoples due to a stronger diffusion of technology. Ashraf and Galor (2010) argue that there is a trade-off in how the level of genetic variation in populations within countries affects economic performance. On the one hand, more genetic variation should make an intergenerational transmission of human capital more difficult.…”

The agricultural basis of comparative development

“…Other recent research concerned with bio-geographical elements of long-run development includeAshraf and Galor (2009),Dalgaard and Strulik (2007),Galor and Michalopoulos (2011),Galor and Moav (2002),Lagerlöf (2003),Michalopolous (2008), andOlsson and Hibbs (2005). 10 This article differs from the work ofBoserup (1965), even though she is interested as well in the intensity of agricultural labor use.…”