Diffusion of innovation in family size ideation and acceptability of contraceptive use between migrants and non-migrants in rural Senegal

Background: Urban–rural diffusion of family-building ideals, beliefs, and behaviors has long been hypothesized to drive fertility transitions. Though the idea is supported on the aggregate level, little prior research has addressed individual-level diffusion. Understanding such mechanisms may be especially important in the high-fertility context of sub-Saharan Africa. Objective: We estimate the association of exposure of rural residents in a small Senegalese population to urban migrants and non-migrant urban residents in their social networks and their beliefs about ideal family size and the acceptability of contraceptive use. We address hypothesized mediating mechanisms and moderating effects of network density. Methods: Data are drawn from the Niakhar Social Networks and Health Project, a large-scale social network survey, and the Niakhar Demographic and Health Surveillance System. Nested models are estimated with migrant exposure operationalized as both the proportion of migrants and the average duration of migration to the capital, Dakar, in respondents’ social networks. Results: Contraceptive approval and numeric response to ideal family size are strongly associated with migrant exposure in men’s social networks but not women’s. This is explained by differences in network density and the prevalence of these ideals in networks. Migrant exposure is associated with lower ideal family sizes for both men and women. Contribution: We find support for social learning and influence effects associated with exposure to migrants on key ideals and beliefs about family size and contraception use, and we find moderating effects of network density. Our findings have potentially important implications for family planning policy and programmatic efforts in the region.