Games that appear to be independent, involving none of the same players, may be related by emotions of reciprocity between the members of the same groups. In the real world, individuals are members of groups and want to reward or punish those groups whose members have been kind or unkind to...

This paper studies the evolution of both characteristics of reciprocity - the willingness to reward friendly behavior and the willingness to punish hostile behavior. Firstly, preferences for rewarding as well as preferences for punishing can survive evolution provided individuals interact within...

We study the effects of group identity on cooperation in experimental two-person strategic games. Our results show that in games of strategic complements, group identity only matters initially when a participant interacts with another participant of the same group by delivering more cooperative...

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...