Cash Crops, Print Technologies and the Politicization of Ethnicity in Africa

What are the origins of the ethnic landscapes in contemporary states? Drawing on a pre-registered research design, we test the impact of dual socioeconomic revolutions that spread across Africa in the 19th and 20th centuries - export agriculture and print technologies. We argue these changes transformed ethnicity via their effects on politicization and boundary-making. Print technologies strengthened imagined communities, leading to more salient yet porous-ethnic identities. Cash crop endowments increased groups' mobilizational potential but with more exclusionary boundaries to control agricultural rents. Using historical data on cash crops and African language publications, we find that groups exposed to these historical forces are more likely to be politically relevant in the post-independence period, and their members report more salient ethnic identities. We observe heterogenous effects on boundary-making as measured by inter-ethnic marriage; relative to cash crops, printing fostered greater openness to assimilate linguistically-related outsiders. Our findings not only illuminate the historical sources of ethnic politicization, but mechanisms shaping boundary formation.