Complementarity in the Private Provision of Public Goods by Homo Pecuniarius and Homo Behavioralis • Job Talk

We examine coordination in private provision of public goods when agents' contributions are complementary. When complementarity is sufficiently high an additional full-contribution equilibrium emerges. We experimentally investigate subjects' behaviour using a between-subject design that varies complementarity. When two equilibria exist, subjects coordinate on the full-contribution equilibrium. When complementarity is sizable but only a zero-contribution equilibrium exists, subjects persistently contribute above it. Choice and non-choice data reveal heterogeneity among subjects and two distinct types. Homo pecuniarius maximizes profits by best-responding to beliefs, while Homo behavioralis identifies this strategy but chooses to deviate from it, sacrificing pecuniary rewards to support altruism or competitiveness.