Some philosophers and social scientists have stressed the importance for good government of an altruistic citizenry that values the well being of one another. Others have emphasized the need for incentives that induce even the self interested to contribute to the public good. Implicitly most...

Does the cultural background influence the success with which genetically unrelated individuals cooperate in social dilemma situations? In this paper we provide an answer by analyzing the data of Herrmann et al. (Science 2008, pp. 1362-1367), who study cooperation and punishment in sixteen...

This paper presents a formal theory of reciprocity. Reciprocity means that people reward kind actions and punish unkind ones. The theory takes into account that people evaluate the kindness of an action not only by its consequences but also by the intention underlying this action. The theory...

We study cooperation within and between groups in the laboratory, comparing treatments in which two groups have previously been (i) in conflict with one another, (ii) in conflict with a different group, or (iii) not previously exposed to conflict. We model conflict using an inter-group Tullock...

We study cooperation within and between groups in the laboratory, comparing treatments in which two groups have previously been (i) in conflict with one another, (ii) in conflict with a different group, or (iii) not previously exposed to conflict. We model conflict using an inter-group Tullock...

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,...

We provide a test of the role of social preferences and beliefs in voluntary cooperation and its decline. We elicit individuals' cooperation preferences in one experiment and use them as well as subjects' elicited beliefs to explain contributions to a public good played repeatedly. We find...

In social dilemmas, there is tension between cooperation that promotes the common good and the pursuit of individual interests. International climate change negotiations provide one example: although abatement costs are borne by individual countries, the benefits are shared globally. We study a...

Extensive experimental research on public goods games documents that many subjects are “conditional cooperators” in that they positively correlate their contributions with (their belief about) contributions of other subjects in their group. The goal of our study is to shed light on what...