Psychological games: theoretical findings and experimental evidence
Résumé
Most economic models assume that agents maximize their expected material payoff. However, subjects in the lab exhibit persistent and significant deviations from this self-interested maximizing behavior. A reasonable explanation for this behavior is that players can be motivated not only by material (monetary) payoffs but also by what are sometimes called "psychological" payoffs. These are related to preferences that are in some degree "other regarding": they take others into account. Traditional game theory does not provide enough tools in order to adequately describe many of these preferences: the traditional approach assumes that payoffs depend only on the actions that are chosen by the players. By contrast, when players are emotional or motivated by reciprocity or social respect, their payoffs may also depend directly on which beliefs (about choices, beliefs, or information) they hold. Therefore, when we deal with intention-based feelings, emotions and social norms, i.e. belief-dependent motivations, we need to turn to Psychological Game Theory, which allows utilities to depend also on beliefs. In this chapter, we provide the main theoretical insights of the general psychological game framework, through an example of a simple trust game in which belief-dependent motivations are involved. Then, we discuss the main experimental works that directly or indirectly refer to psychological game-theoretic explanations as able to rationalize their experimental results. Throughout the chapter, we try to clarify ideas and to dispel misconceptions emerged among economists about this new field, in order to stress the role and the importance of psychological games both for the strategic interaction analysis and for the related experimental applications.