Does Public Policy Crowd Out Private Contributions to Public Goods

It is sometimes claimed that individuals' contributions topublic goods are not motivated by economic costs and benefitsalone, but that people also have a moral or norm-basedmotivation. A number of studies indicate that such moral ornorm-based motivation might be crowded out, or crowded in, bypublic policy. This paper discusses some models that can yieldinsight into the interplay between economic and moral ornorm-based motivation for voluntary contributions to publicgoods, and compares their policy implications. We distinguishbetween five types of models: Altruism models, social normmodels, fairness models, models of commitment and thecognitive evaluation theory.