Do Peers Increase the Voluntary Contributions of Low Contributors to Group Projects? And How? Evidence from a Field Experiment

In this paper, we vary exogenously the proportion of high contributors in meetings that are designed to encourage the contributions of low contributors to a real-world communitybased electri…cation project. We …nd that low contributors contribute more after they attended a “mixed”meeting, i.e., with some high contributors, rather than a “low meeting”, i.e., with no high contributors. We explore four mechanisms that could explain this result: shaming, encouragement, reciprocity, learning about the bene…ts of the project, through a combination of detailed data collection on the behavior of meeting attendees, and additional experiments designed to test in isolation each mechanism. In fact, we …nd support for an additional channel that has not been explored before: the removal of uncertainty about the project by high contributors. Keywords: contributions, peer e¤ects. JEL Classi…cation: O12, O17. We thank GPower and members of the Kiangurwe community. We received valuable suggestions from Shawn Cole, Giacomo De Giorgi, Pascaline Dupas, Tobias Kalenscher, Nancy Qian, Dean Yang, participants of the 2010 BREAD/CIRPÉE Conference, and seminars at the University of Ottawa, Carleton University, and The World Bank. Robin Audy, Veronicah Gachoki,Elijah Gachuhi, Jennie Glassco, Ellen Moscoe, Antony Karanja, Evans Kariuki, Kelvin Kinyua, James Muchira, Kelvin Muriuki, Veronique Russell, Jannis Visser, Anthony Wainaina, Dominicah Waweru provided excellent research assistance. This research was supported by FQRSC, the French Embassy in Kenya, IDRC, SSHRC, Stichting Dioraphte, World Bank. All errors are ours. The opinions expressed are those of the authors alone and do not necessarily re‡ect those of the World Bank Group. Corresponding Author: Matthieu Chemin, McGill University, Canada, tel: 514-398-4400 ext. 09050, fax: 514-398-4938