合作(cooperation)行为的进化机制是种群进化生物学最重要的理论命题之一。2002年瑞士学者Fehr和Gachter发表在Nature的论文中指出惩罚(punishment)是促进合作的有效机制，这一观点很快被学术界广泛接受。2008年Harvard大学的Nowak研究组在Nature上发表了关于可重复囚徒困境(repeated Prisoner's Dilemma)博弈的实验研究，他们的结果也表明有代价处罚(costly punishment)能够有效地促进合作。
但是一项最新的研究结果表明在可重复囚徒困境博弈中有代价惩罚并不总是促进合作。这一结果将促进人们去更进一步的思考惩罚是怎样作用于合作行为的进化。由中科院动物研究所陶毅研究组完成的这一最新研究结果已于2009年9月28日在《美国国家科学院院刊》（Proceeding of National Academy of Sciences USA)在线发表。Nature News在同一天发表评论员文章 (标题为：When does punishment work?)中指出这一研究结果表明在博弈实验中我们会表现出什么样的行为将主要依赖于“我们是谁”。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS September 28, 2009, doi: 10.1073/pnas.0905918106
Costly punishment does not always increase cooperation
Jia-Jia Wua, Bo-Yu Zhanga,b, Zhen-Xing Zhoub, Qiao-Qiao Hea, Xiu-Deng Zhenga, Ross Cressmanc,1 and Yi Taoa,1
aKey Laboratory of Animal Ecology and Conservation Biology, Centre for Computational Biology and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China;
bSchool of Mathematical Sciences, Beijing Normal University, Beijing 100875, China; and
cDepartment of Mathematics, Wilfrid Laurier University, Waterloo, ON, Canada N2L 3C5
In a pairwise interaction, an individual who uses costly punishment must pay a cost in order that the opponent incurs a cost. It has been argued that individuals will behave more cooperatively if they know that their opponent has the option of using costly punishment. We examined this hypothesis by conducting two repeated two-player Prisoner's Dilemma experiments, that differed in their payoffs associated to cooperation, with university students from Beijing as participants. In these experiments, the level of cooperation either stayed the same or actually decreased when compared with the control experiments in which costly punishment was not an option. We argue that this result is likely due to differences in cultural attitudes to cooperation and punishment based on similar experiments with university students from Boston that found cooperation did increase with costly punishment.
