Victory and Defeat in a Model of Behavior in Games and Toward Risk

The standard expected utility model is augmented by allowing individuals to receive additional utility in states in which they consider themselves victorious and to lose a utility increment in which they consider themselves defeated. The resulting event-dependent expected utility model is used to explain behavior in games and toward risk. In games, players consider themselves defeated when their monetary payoffs are low compared to their opponents' payoffs, and they consider themselves victorious when their payoffs are high, but not too high, compared to their opponents' payoffs. Under these conditions the model can accommodate behavior that has been interpreted elsewhere as inequity aversion, as well as cooperation in the prisoner's dilemma and in public good provision games. In situations of risk, individuals consider themselves victorious (defeated) when they receive an unlikely, avoidable, high (low) outcome. Under these conditions the model can accommodate such behavior as the Allais paradox, boundary effects, and simultaneous gambling and insurance. Consequently, the model uses a single framework to discuss evidence from two distinct branches of the literature.