title: Humans expect generosity.
abstract: Mechanisms supporting human ultra-cooperativeness are very much subject to debate. One psychological feature likely to be relevant is the formation of expectations, particularly about receiving cooperative or generous behavior from others. Without such expectations, social life will be seriously impeded and, in turn, expectations leading to satisfactory interactions can become norms and institutionalize cooperation. In this paper, we assess people's expectations of generosity in a series of controlled experiments using the dictator game. Despite differences in respective roles, involvement in the game, degree of social distance or variation of stakes, the results are conclusive: subjects seldom predict that dictators will behave selfishly (by choosing the Nash equilibrium action, namely giving nothing). The majority of subjects expect that dictators will choose the equal split. This implies that generous behavior is not only observed in the lab, but also expected by subjects. In addition, expectations are accurate, matching closely the donations observed and showing that as a society we have a good grasp of how we interact. Finally, correlation between expectations and actual behavior suggests that expectations can be an important ingredient of generous or cooperative behavior.
authors.affiliation: Middlesex University London, Department of Economics, Business School, Hendon Campus, The Burroughs, London NW4 4BT, United Kingdom.
authors.forename: Pablo
authors.initials: P
authors.lastname: Brañas-Garza
authors.affiliation: Middlesex University London, Department of Economics, Business School, Hendon Campus, The Burroughs, London NW4 4BT, United Kingdom.
authors.forename: Ismael
authors.initials: I
authors.lastname: Rodríguez-Lara
authors.affiliation: Grupo Interdisciplinar de Sistemas Complejos, Departamento de Matemáticas, Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain.|Institute UC3M-BS of Financial Big Data, Universidad Carlos III de Madrid, 28903 Getafe, Spain.|Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, 50018 Zaragoza, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Sánchez
mesh_terms: D003299:Cooperative Behavior; D005717:Games, Experimental; D006801:Humans; D008960:Models, Psychological