Estimating Social Norm Complementarities

2026-05-14

AI Summary

This study investigates the interplay—whether complementary or substitutive—among social norms such as female genital cutting, polygyny, and child marriage. To this end, it develops a two-dimensional structural choice model that integrates technological complementarities with social conformity payoffs, identifying interaction mechanisms through how the equilibrium utility of one norm responds to changes in another. The model is estimated using repeated cross-sectional data from Sierra Leone and Nigeria. This work is the first to unify technological and social complementarities within a single analytical framework, systematically characterizing norm interdependencies while incorporating anthropological insights to explain regional variation. Empirical results reveal that female genital cutting and child marriage are significantly complementary—especially in Sierra Leone—whereas polygyny and child marriage exhibit a socially substitutive relationship, particularly in Nigeria. Social conformity payoffs are consistently significant, offering quantitative foundations for legal reform and policy interventions.

Abstract

We develop a model of choice over social norms that allows for complementarities along two dimensions: \textit{technological}, analogous to complementarities between consumption goods, and social, capturing returns from conformity. Together, these determine whether two norms are complements, substitutes, or independent, as defined by how the equilibrium prevalence of one norm responds to a marginal shift in the utility of another. We estimate the model using repeated cross-sections from Sierra Leone and Nigeria, focusing on female genital cutting, polygyny, and child marriage. Social returns are significant across all specifications. For female genital cutting and child marriage, we find evidence of complementarities, especially strong in Sierra Leone. For polygyny and child marriage, we find evidence of social substitutability, particularly in Nigeria. We interpret these differences using insights from anthropology. Finally, we iterate the model forward to study policy counterfactuals, assessing the potential effects of legal reforms and social interventions.

Problem

• social norms
• complementarities
• substitutability
• female genital cutting
• child marriage

Innovation

• social norm complementarities
• structural estimation
• conformity returns
• policy counterfactuals
• cross-norm interactions