Economic and social interaction takes place between individuals with heterogeneous characteristics. We investigate experimentally the emergence and informal enforcement of different contribution norms to a public good in homogeneous and different heterogeneous groups. When punishment is not...

We model a contest between two groups of equal population size over the division of a group-specific public good. Each group is fragmented into sub-groups. Each sub-group allocates effort between production and contestation. There is perfect coordination within sub-groups, but sub-groups cannot...