Program for Evolutionary Dynamics, Harvard University, Cambridge, Massachusetts 02138, USA.
Nat Commun. 2011 Aug 16;2:434. doi: 10.1038/ncomms1442.
Cooperation, where one individual incurs a cost to help another, is a fundamental building block of the natural world and human society. It has been suggested that costly punishment can promote the evolution of cooperation, with the threat of punishment deterring free-riders. Recent experiments, however, have revealed the existence of 'antisocial' punishment, where non-cooperators punish cooperators. While various theoretical models find that punishment can promote the evolution of cooperation, these models a priori exclude the possibility of antisocial punishment. Here we extend the standard theory of optional public goods games to include the full set of punishment strategies. We find that punishment no longer increases cooperation, and that selection favours substantial levels of antisocial punishment for a wide range of parameters. Furthermore, we conduct behavioural experiments, showing results consistent with our model predictions. As opposed to an altruistic act that promotes cooperation, punishment is mostly a self-interested tool for protecting oneself against potential competitors.
合作是指一个人为帮助另一个人而付出代价，它是自然界和人类社会的基本组成部分。有人认为，昂贵的惩罚可以促进合作的进化，因为惩罚的威胁可以阻止搭便车者。然而，最近的实验揭示了“反社会”惩罚的存在，即不合作者会惩罚合作者。虽然各种理论模型发现惩罚可以促进合作的进化，但这些模型先验地排除了反社会惩罚的可能性。在这里，我们将标准的可选公共物品博弈理论扩展到包括完整的惩罚策略集。我们发现，惩罚不再增加合作，选择有利于在广泛的参数范围内进行大量的反社会惩罚。此外，我们进行了行为实验，结果与我们的模型预测一致。与促进合作的利他行为相反，惩罚主要是一种保护自己免受潜在竞争对手侵害的自利工具。
