This paper studies the impact of the presence of human subjects in the role of a seller on bidding in experimental second-price auctions. Overbidding is a robust finding in second- price auctions, and spite among bidders has been advanced as an explanation. If spite extends to the seller, then...

Behavioral robustness is essential in mechanism design. Existing papers focus on robustness as captured by dominant strategies. This paper studies the novel concept of externality-robustness, which addresses players' motives to affect other players' monetary payoffs. One example is externalities...

Behavioral robustness is essential in mechanism design. Existing papers focus on robustness as captured by dominant strategies. This paper studies the novel concept of externality-robustness, which addresses players' motives to affect other players' monetary payoffs. One example is externalities...

We study optimal incentive contracts with multiple agents when performance evaluation is delegated to a reviewer. The reviewer may be biased in favor of the agents, but the degree of the bias is unknown to the principal. We show that a contest, which is a contract in which the principal...

An auction is externality-robust if unilateral deviations from equilibrium leave the other bidders' payoffs unaffected. The equilibrium and its outcome will then persist if certain types of externalities arise between bidders. One example are externalities due to spiteful preferences, which have...

An auction is externality-robust if unilateral deviations from equilibrium leave the other bidders' payoffs unaffected. The equilibrium and its outcome will then persist if certain types of externalities arise between bidders. One example are externalities due to spiteful preferences, which have...

Behavioral robustness is essential in mechanism design. Existing papers focus on robustness as captured by dominant strategies. This paper studies the novel concept of externality-robustness, which addresses players' motives to affect other players' monetary payoffs. One example is externalities...

We study games in which multiple principals influence the choice of a privately-informed agent by offering action-contingent payments. We characterize the equilibrium allocation set as the maximizers of an endogenous aggregate virtual-surplus program. The aggregate maximand for every equilibrium...

We present a Theory of Contracts under costly enforcement in the context of a dynamic relationship between an uninformed buyer and a seller who is privately informed on his persistent cost at the outset. Public enforcement relies on remedies for breach. Private enforcement comes from severing...

An aggregate game is a normal-form game with the property that each player's payoff is a function of only his own strategy and an aggregate of the strategy profile of all players. Such games possess properties that can often yield simple characterizations of equilibrium aggregates without re-...