Contests between groups are plagued by intra-group externalities (freeriding). Yet, costless incentive schemes that entirely avoid free-riding within a group might not be desirable, neither individually nor socially. In contests among two groups, a relatively weak (i.e., small or unproductive)...

Lecture on the first SFB/TR 15 meeting, Gummersbach, July, 18 - 20, 2004: This paper models the trade-off between production and appropriation in the presence of simultaneous inter- and intra-group conflicts. The model exhibits a ' group cohesion effect ': if the contest between the groups...

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 physicians are often expected to be gatekeepers to health insurance benefits such as paid sick leave, research indicates a substantial reluctance to reject patient requests for sickness certificates. We show that private information on the patient's part creates a conflict between the...