Ancestral Composition Distance

This paper introduces Ancestral Composition Distance (ACD); a bilateral measure of how similarly two countries assemble their populations from a common set of ancestral clusters. Each cluster contains countries whose native populations were culturally close around 1500. Across a global sample of country dyads (involving 163 countries), greater ancestral composition distance is systematically associated with greater contemporary cultural distance and human capital gap. More ancestrally distant countries also exhibit larger differences in income, human development, institutional characteristics, and foreign-policy positions, while trading less and exchanging fewer migrants. These relationships survive an extensive set of geographic, historical, institutional, genetic, linguistic, and religious controls, indicating that ACD captures a dimension of bilateral relatedness not summarized by standard measures. Decomposing ACD into differences already present in 1500 and differences that emerged due to post-Columbian population movements, we show that pairs whose ancestral compositions converged after 1500 are culturally closer today, conditional on their initial ancestral separation. All these results are robust to alternative ways to group countries into pre-1500 cultural clusters. We view ACD both as a useful measure for understanding contemporary cultural differences as well as a historically determined bilateral resistance term that complements conventional measures of geography, shared history, and population relatedness