We experimentally study endogenous alliance formation and contest effort choices in a generic three-player contest. Differences in intrinsic or extrinsic incentives to expend effort cause self-selection. Weakly motivated players have an incentive to enter into an alliance and to free-ride on...

We study collective action under adverse incentives: each member of the group has a given budget ('use-it-or-lose-it') that is his private information and that can be used for contributions to make the group win a prize and for internal fights about this very prize. Even in the face of such...

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...