A long time ago most economists would have limited themselves to stating that agreements should be individually rational and efficient and that selecting a specific agreement from that set depends on bargaining and negotiation power whatever that may be. Nowadays hardly any economist will argue...

Abundant evidence suggests that high levels of contributions to public goods can be sustained through self-governed monitoring and sanctions. This experimental study investigates the effectiveness of decentralized sanctioning institutions where punishment opportunities are restricted to agents...

People exhibit group reciprocity when they retaliate, not against the person who harmed them, but against somebody else in that person's group. Group reciprocity may be a key motivation behind intergroup conflict. We investigated group reciprocity in a laboratory experiment. After a group...

Numerous studies suggest that communication may be a universal means to mitigate collective action problems. In this study, we challenge this view and show that the communication structure crucially determines whether communication mitigates or intensifies the problem of collective action. We...

In experiments, people behave more cooperatively when they are aware of an external threat, while in the field, we observe surprisingly high levels of cooperation and altruism within groups in conflict situations such as civil wars. We provide an explanation for these phenomena. We introduce a...

We experimentally test the social motives behind individual participation in intergroup conflict by manipulating the framing and symmetry of conflict. We find that behavior in conflict depends on whether one is harmed by actions perpetrated by the out-group, but not on one’s own influence on...

Although one may hope to achieve equality of stated profits without enforcing it, one may not trust in such voluntary equality seeking and rather try to impose rules (of bidding) guaranteeing it. Our axiomatic approach is based on envy-free net trades according to bids which, together with the...

Envy is often the cause of mutually harmful outcomes. We experimentally study the impact of envy in a bargaining setting in which there is no conflict in material interests: a proposer, holding the role of residual claimant, chooses the size of the pie to be shared with a responder, whose share...

We enrich the choice task of responders in ultimatum games by allowing them to independently decide whether to collect what is offered to them and whether to destroy what the proposer demanded. Such a multidimensional response format intends to cast further light on the motives guiding responder...

A group of actors, individuals or firms, can engage in collectively providing projects which may be costly or generating revenues and which may benefit some and harm others. Based on requirements of procedural fairness (Güth and Kliemt, 2013), we derive a bidding mechanism determining...