Working Paper: CEPR ID: DP13437
Authors: Matteo Cervellati; Giorgio Chiovelli; Elena Esposito
Abstract: We investigate the epidemiological origins of ethnic diversity and its persistence. First, we conceptualize the role of malaria for the incentives to voluntary isolation in a Malthusian environment. The theory predicts that interactions in multiple geographically clustered groups with high sexual endogamy allowed limiting disease prevalence and increasing group fitness in pre-modern populations exposed to malaria. Second, using disaggregate level data, we document the hitherto unexplored and robust role of malaria for pre-colonial, historical and contemporaneous ethnic diversity in Africa. Third, falsification tests based on malaria epidemiology and history further allow us to validate the specific predictions of the model. No effect can be detected for other placebo vector-borne diseases. Malaria is a main driver of pre-colonial ethnic diversity in Africa but not in the Americas, where the pathogen was absent before European colonization. Fourth, the effect of ancestral malaria on endogamic cultures is the main predicted channel for the persistence of African ethnicities. Exploiting within village variation across 18 African countries, we find that ancestral malaria, but not malaria today, still affects the differential persistence of ethnicities through its legacy of active endogamic cultures.
Keywords: Malthusian theory; Ethnic groups; Cultural and genetic selection; Malaria; Endogamy; African growth
JEL Codes: N10; N30; O10; O40; Z10
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| long-term exposure to malaria (I12) | emergence and persistence of ethnic groups (Z13) |
| higher ancestral malaria exposure (I14) | increased ethnic diversity (J15) |
| long-term exposure to malaria (I12) | formation of endogamic cultures (Z13) |
| formation of endogamic cultures (Z13) | limit interactions across groups (C92) |
| limit interactions across groups (C92) | reduce disease prevalence (I12) |
| reduce disease prevalence (I12) | enhance group fitness (C92) |
| malaria's influence is absent in the Americas (N96) | suggests unique role for malaria in shaping African ethnicities (Z13) |
| legacy of malaria (I12) | affects ethnic persistence (J15) |