The paper presents an expository account of several experimentally based descriptive theories of cooperation in interactive decision situations. First the equity principle (Selten 1988), prominence in the decimal system (Albers and Albers 1983), and the difference measure of predictive success...

Second price allpay auctions (wars of attritions) have an evolutionarily stable equilibrium in pure strategies if valuations are private information. I show that for any level of uncertainty there exists a pure deviation strategy close to the equilibrium strategy such that for some valuations...

We provide an evolutionary foundation to evidence that in some situations humans maintain optimistic or pessimistic attitudes towards uncertainty and are ignorant to relevant aspects of the environment. Players in strategic games face Knightian uncertainty about opponents' actions and maximize...

We analyze explicit and implicit contracts in a repeated principal-agent model with observable but only partially contractible actions of the agent. It is shown that the set of implementable actions may increase or decrease if additional actions become contractible.

We study the Fictitious Play process with bounded and unbounded recall in pure coordination games for which failing to coordinate yields a payoff of zero for both players. It is shown that every Fictitious Play player with bounded recall may fail to coordinate against his own type. On the other...