Why do people engage in costly cooperation with unknown others that they will never meet again? Answers to this evolutionary puzzle emphasize the role of indirect reciprocity (i.e., cooperation through reputation), whereby cooperation is not reciprocated by the recipient but by other members of...

Social norms permeate society across a wide range of issues and are important to understanding how societies function. In this paper we concentrate on 'bad' social norms - those that are inefficient or even damaging to a group. This paper explains how bad social norms evolve and persist; our...