For a policy maker promoting the end of a harmful tradition, conformist social influence is a compelling mechanism. If an intervention convinces enough people to abandon the tradition, this can spill over and induce others to follow. A key objective is thus to activate spillovers and amplify an intervention's effects. With female genital cutting as a motivating example, we develop empirically informed analytical and simulation models to examine this idea. Even if conformity pervades decision making, spillovers can range from irrelevant to indispensable. Our analysis highlights three considerations. First, ordinary forms of individual heterogeneity can severely limit spillovers, and understanding the heterogeneity in a population is essential. Second, although interventions often target biased samples of the population, targeting a representative sample is a more robust approach to spillovers. Finally, if the harmful tradition contributes to group identity, spillovers can hinge critically on disrupting the link between identity and tradition.
Charles Efferson is a Professor in the Department of Organizational Behavior at HEC Lausanne, University of Lausanne. He is an evolutionary ecologist focused on the evolution of human social cognition and human social behavior. He routinely mixes evolutionary modeling with the analysis of both experimental and observational data. Much of his current empirical research examines the social mechanisms underlying harmful cultural traditions and, alternatively, the diffusion of beneficial innovations.