This paper estimates people’s taste for living with own-ethnic-group neighbors using variation from a natural experiment in Singapore: ethnic housing quotas. I develop a location choice model that informs the use of policy variation from the quotas to address endogeneity issues well-known in the social interactions literature. I assembled a dataset on neighborhood level ethnic proportions by matching more than 500,000 names in the phonebook to ethnicities. I find that all groups want to live with some own-ethnic-group neighbors but they also exhibit inverted U-shaped preferences so that once a neighborhood has enough own-ethnic-neighbors, they would rather add a new neighbor from other groups. Welfare simulations show that about 30% of the neighborhoods are within one standard deviation of the first best allocation of ethnic groups.

We use a population resettlement program in Indonesia to identify long-run effects of intergroup contact on national integration. In the 1980s, the government relocated two million ethnically diverse migrants into hundreds of new communities. We find greater integration in fractionalized communities with many small groups, as measured by national language use at home, intermarriage, and children’s name choices. However, in polarized communities with a few large groups, ethnic attachment increases and integration declines. Residential segregation dampens these effects. Social capital, public goods, and ethnic conflict follow similar patterns. Overall, our findings highlight the importance of localized contact in shaping identity.