We find the sufficient conditions for the existence of multiple equilibria in Tullock-type contests, and show that asymmetric equilibria arise even under symmetric prize and cost structures. We then present existing contests where multiple equilibria exist under reasonably weak conditions.

We consider a multi-winner nested elimination contest in which losers are sequentially eliminated to attain the set of winners. This is a variant of a widely used mechanism introduced by Clark and Riis (1996) that allows one to select the winners sequentially. We show that the current mechanism...

We show in a public goods experiment on three continents that conditional cooperation is a universal behavioral regularity. Yet, the number of conditional cooperators and the extent of conditional cooperation are much higher in the United States than anywhere else.

The effects of stake size on cooperation and punishment are investigated using a public goods experiment. We find that an increase in stake size does neither significantly affect cooperation nor the level of punishment.