Weak Moral Motivation Leads to the Decline of Voluntary Contributions

Abstract

We develop a model that accounts for the decay of the average contribution observed in experiments on voluntary contributions to a public good. The novel idea is that people's moral motivation is "weak." Their judgment about the right contribution depends on observed contributions by group members and on an intrinsic "moral ideal." We show that the assumption of weakly morally motivated agents lead to the decline of the average contribution over time. The model is compatible with persistence of over-contributions, variability of contributions (across and within individuals), and the "restart effect." Furthermore, it offers a rationale for conditional cooperation.

Keywords: Conditional Cooperation, Voluntary Contributions, Moral Motivation, Experiments on Public Goods Games

JEL Classification: H00, H41, C72