Free-riding on altruistic punishment? An experimental comparison of third-party-punishment in a stand-alone and in an in-group environment.

This paper deals with the subject of third-party punishment. The paper compares, by means of an economic experiment, punishment by a third party (Stand-Alone case) with punishment by third parties (In-Group environment). This deliberate introduction of a second potential punisher is neither subtle nor marginal. Shifting punishment choices into this "enlarged environment" allows us to study, in a systematic way, the complex relationship between the punisher's expectations about her/his peer's punishment decisions and her/his own punishment choices. In particular, we aim to examine whether, on average, individual punishment is systematically lower in an In-Group environment compared with the Stand-Alone case.