In the two-person sequential best shot game, first player 1 contributes to a public good and then player 2 is informed about this choice before contributing. The payoff from the public good is the same for both players and depends only on the maximal contribution. Efficient voluntary cooperation...

Stochastic uncertainty can cause difficult coordination problems that may hinder mutually beneficial cooperation. We propose a mechanism of ex-post voluntary transfers designed to circumvent these coordination problems and ask whether it can do so. To test this, we implement a controlled...

Repeated interactions provide a prominent but paradoxical hypothesis for human cooperation in one-shot interactions 1–3. Intergroup competitions 4–7 provide a different hypothesis that is intuitively appealing but heterodox. We show that neither mechanism reliably supports the evolution of...