Consider a situation where person A undertakes a costly action that benefits person B. This behavior seems altruistic. However, if A expects a reward in return from B, then A's action may be motivated by the expected rewards rather than by pure altruism. The question we address in this...

This paper presents a formal theory of reciprocity. Reciprocity means that people reward kind actions and punish unkind ones. The theory takes into account that people evaluate the kindness of an action not only by its consequences but also by the intention underlying this action. The theory...

In this paper we show that a simple model of fairness preferences explains major experimental regularities of common pool resource (CPR) experiments. The evidence indicates that in standard CPR games without communication and without sanctioning possibilities inefficient excess appropriation is...