In this paper we show experimentally that conditional cooperation, a phenomenon described in the private provision of public goods, is also present in group contests, where participants’ contributions to their group performance partially determines if they overcome a rival group. This...

I analyse a group contest in which groups decide over two dimensions of membership-exclusivity: whether a member is allowed to join the group at all, and whether this member is allowed to join another group as well. If the prize is mostly private, group leaders do not offer membership in...

Interrelated global crises - climate change, pandemics, loss of ecosystem services and biodiversity - pose risks that demand collective solutions. Uncertainty about others' behavior, coupled with the dependence on some to take collective efforts to mitigate risks for all (e.g. conservation of...