Ethnic identity, cross-ethnic sexual network formation, and HIV/AIDS in Africa

Roland Pongou, Brown University

We develop a simple theory of how community-level ethnic heterogeneity determines sexual network formation, and how this in turn affects the diffusion of HIV/AIDS. The model is built on the assumption that agents derive utility from sexual relationships, but sexual infidelity is socially prohibited and penalized if detected. It implies a mechanism wherein ethnic heterogeneity provides incentives for optimizing agents to multiply sexual partners across ethnic groups, and thus positively affects the spread of HIV/AIDS. The theory is tested using micro level data from six representative sub-Saharan African countries. We find a direct effect of ethnic heterogeneity on the number of sexual partners as well as HIV infections. Robustness checks show that this effect is not driven by a lack of public goods in ethnically diverse communities. Interestingly, ethnic heterogeneity is also shown to have no effect on anemia, which unlike HIV/AIDS does not spread through socially prohibited human interactions.