The assumption that decision makers choose actions to maximize their preferences is a central tenet in economics. This assumption is often justied either formally or informally by appealing to evolutionary arguments. In contrast, we show that in almost every game and for almost every family of...

The assumption that decision makers choose actions to maximize their preferences is a central tenet in economics. This assumption is often justified either formally or informally by appealing to evolutionary arguments. In contrast, this paper shows that in almost every game, payoff maximization...

Successful individuals were frequently found to be overly optimistic. These findings are puzzling, as one could expect that realists would perform best in the long run. We show, however, that in a large class of strategic interactions of either cooperation or competition, the equilibrium payoffs...