Human cooperation is an evolutionary puzzle. Unlike other creatures, people frequently cooperate with genetically unrelated strangers, often in large groups, with people they will never meet again, and when reputation gains are small or absent. These patterns of cooperation cannot be explained...

We present a simple classroom principal-agent experiment that can effectively be used as a teaching device to introduce important concepts of organizational economics and contracting. In a first part, students take the role of a principal and design a contract that consists of a fixed payment...

This paper discusses the empirical evidence from lab and field experiments on voluntary cooperation. We present the most important findings from numerous public goods experiments and argue that conditional cooperation (contributions are conditional on other people’s contribution) is a primary...

Loss aversion, the fact that losses have a greater impact than gains, is a fundamental property of behavioral accounts of choice. In this paper, we suggest four possible characterizations of the relative impact of losses and gains: (1) It could be a constant, such as the much cited value of 2,...

One lingering puzzle is why voluntary contributions to public goods decline over time in experimental and real-world settings. We show that the decline of cooperation is driven by individual preferences for imperfect conditional cooperation. Many people’s desire to contribute less than others,...

An extensive literature demonstrates the existence of framing effects in the laboratory and in questionnaire studies. This paper reports new evidence from a natural field experiment using a subject pool one may consider as particularly resistant to such effects: experimental economists. We find...

We report evidence from public goods experiments with and without punishment which we conducted in Russia with 566 urban and rural participants of young and mature age cohorts. Russia is interesting for studying voluntary cooperation because of its long history of collectivism, and a huge...

We report an experiment comparing sequential and simultaneous contributions to a public good in a quasi-linear two-person setting (Varian, Journal of Public Economics, 1994). Our findings support the theoretical argument that sequential contributions result in lower overall provision than...