This paper investigates how punishment promotes cooperation when the punishment enforcer is independent of its proposer. In a prisoner's dilemma experiment, compared with the case when the implicated parties are allowed to punish each other, cooperation is lower when the enforcement of...

This paper investigates how punishment promotes cooperation when the punishment enforcer is a third party independent of the implicated parties who propose the punishment. In a prisoner's dilemma experiment, we find an independent third party vetoes not only punishment to the cooperators but...

In a prisoner’s dilemma experiment, compared with the case when the implicated parties are allowed to punish each other, both the cooperation rate and the earnings are lower when the enforcement of punishment requires approval from an independent third party.