Alliances often provide a collective good among their allies. This article offers laboratory experimental evidence that the possibility to vote for the exclusion of non-cooperating allies, i.e. ostracism, can be a powerful negative referendum to increase allies’ contributions to the collective...

Previous research has shown that opportunities for two-sided partner choice in finitely repeated social dilemma games can promote cooperation through a combination of sorting and opportunistic signaling, with late period defections by selfish players causing an end-game decline. How such...

We experimentally compare the consequences for group cooperation of two decision mechanisms involving the extension of group membership. We analyze an exogenous decision (random draw) and an endogenous decision (made by a particular group member) mechanism to extend a temporary agent's group...

A lot of economic and social situations can be described as contests in which agents need to distribute scare resources. Individual behavior plays an important role within these situations, while identity strongly impacts on behavior. This paper asks how group identity impacts the provision of a...