2013 年 83 巻 6 号 p. 582-588
In addition to the cost of punishment, the fear that others would evaluate punishers negatively can be a major obstacle for resolving the second-order social dilemma or failure of providing sanctions useful for solving a social dilemma problem. In an experiment with 81 participants, we tested whether providing information that other participants were in favor of punishing non-cooperators in a social dilemma situation would enhance cooperation in the second-order dilemma (i.e., punishment of non-cooperators). Participants received feedback of three bogus “participants” choices in a four-person social dilemma, in which one bogus participant defected and two others cooperated, and then received a chance to punish the sole non-cooperator. The hypothesis was supported among those who were motivated to punish the non-cooperator. They punished the non-cooperator when they were informed that the other participants also wanted to punish the non-cooperator. The feedback information that the other participants wanted to punish the non-cooperator induced the participants who were not motivated to punish the non-cooperator to punish less.