Kuběna Aleš Antonín, Houdek Petr, Lindová Jitka, Příplatová Lenka, Flegr Jaroslav
Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic.
Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic; Department of Economics, Faculty of Social and Economic Studies, J. E. Purkyně University in Ústí nad Labem, Ústí nad Labem, Czech Republic.
PLoS One. 2014 Mar 26;9(3):e92336. doi: 10.1371/journal.pone.0092336. eCollection 2014.
Allowing players to punish their opponents in Public Goods Game sustains cooperation within a group and thus brings advantage to the cooperative individuals. However, the possibility of punishment of the co-players can result in antisocial punishment, the punishment of those players who contribute the most in the group. To better understand why antisocial punishment exists, it must be determined who are the anti-social punishers and who are their primary targets.
For resolving these questions we increased the number of players in a group from usual four to twelve. Each group played six rounds of the standard Public Goods Game and six rounds of the Public Goods Game with punishment. Each player in each round received 20 CZK ($ 1.25). Players (N = 118) were rematched after each round so that they would not take into consideration opponents' past behavior.
The amount of the punishment received correlated negatively with the contribution (ρ = -0.665, p<0.001). However, this correlation was positive for players in the highest contributors-quartile (ρ = 0.254, p<0.001). Therefore, the graph of relation between the contribution given and punishment obtained was U-shaped (R2 = 0.678, p<0.001) with the inflection point near the left boarder of the upper quartile. The antisocial punishment was present in all groups, and in eight out of ten groups the Justine Effect (the positive correlation between the contribution to the public pool and the risk of suffering punishment in the subpopulation of altruistic players) emerged. In our sample, 22.5% subjects, all of them Free riders and low contributors, punished the altruistic players.
The results of our experimental game-study revealed the existence of the Justine effect--the positive correlation between the contribution to the public pool by a subpopulation of the most altruistic players, and the amount of punishment these players obtained from free-riders.
在公共物品博弈中允许玩家惩罚对手能够维持群体内的合作，从而给合作个体带来优势。然而，惩罚同组玩家的可能性可能导致反社会惩罚，即惩罚群体中贡献最大的那些玩家。为了更好地理解反社会惩罚为何存在，必须确定谁是反社会惩罚者以及他们的主要目标是谁。
为了解决这些问题，我们将每组玩家的数量从通常的4人增加到12人。每个组进行六轮标准公共物品博弈和六轮有惩罚的公共物品博弈。每轮每个玩家会得到20捷克克朗（1.25美元）。玩家（N = 118）在每轮后重新匹配，这样他们就不会考虑对手过去的行为。
收到的惩罚量与贡献呈负相关（ρ = -0.665，p < 0.001）。然而，对于贡献最高的四分位数中的玩家，这种相关性是正的（ρ = 0.254，p < 0.001）。因此，给出的贡献与获得的惩罚之间的关系图呈U形（R2 = 0.678，p < 0.001），拐点接近上四分位数的左边界。所有组中都存在反社会惩罚，并且在十分之八的组中出现了贾斯汀效应（在利他主义玩家子群体中，对公共池的贡献与遭受惩罚的风险之间的正相关）。在我们的样本中，22.5%的受试者，他们都是搭便车者和低贡献者，惩罚了利他主义玩家。
我们的实验博弈研究结果揭示了贾斯汀效应的存在——最利他主义的玩家子群体对公共池的贡献与这些玩家从搭便车者那里获得的惩罚量之间的正相关。
