This paper studies how competition between groups affects cooperation. In the control condition, pairs of subjects play an indefinitely repeated Prisoner's Dilemma game without external competition. In the treatment, two pairs compete against each other. No monetary rewards are tied to winning,...

We explore a broad class of values for cooperative games in characteristic function form, known as compromise values. These values efficiently allocate payoffs by linearly combining wellspecified upper and lower bounds on payoffs. We identify subclasses of games that admit nontrivial efficient...

Experiment participants in a social dilemma game choose cooperation over defection, even though neither is more beneficial. High levels of cooperation cannot be explained by favorable labels for actions, collusion, k-level reasoning, quantal response behavior, or misplaced optimism about others'...