Social diversity promotes the emergence of cooperation in public goods games

Humans often cooperate in public goods games and situations ranging from family issues to global warming. However, evolutionary game theory predicts that the temptation to forgo the public good mostly wins over collective cooperative action, and this is often also seen in economic experiments. Here we show how social diversity provides an escape from this apparent paradox. Up to now, individuals have been treated as equivalent in all respects, in sharp contrast with real-life situations, where diversity is ubiquitous. We introduce social diversity by means of heterogeneous graphs and show that cooperation is promoted by the diversity associated with the number and size of the public goods game in which each individual participates and with the individual contribution to each such game. When social ties follow a scale-free distribution, cooperation is enhanced whenever all individuals are expected to contribute a fixed amount irrespective of the plethora of public goods games in which they engage. Our results may help to explain the emergence of cooperation in the absence of mechanisms based on individual reputation and punishment. Combining social diversity with reputation and punishment will provide instrumental clues on the self-organization of social communities and their economical implications.     

Indirect reciprocity can stabilize cooperation without the second-order free rider problem

Models of large-scale human cooperation take two forms. 'Indirect reciprocity' occurs when individuals help others in order to uphold a reputation and so be included in future cooperation. In 'collective action', individuals engage in costly behaviour that benefits the group as a whole. Although the evolution of indirect reciprocity is theoretically plausible, there is no consensus about how collective action evolves. Evidence suggests that punishing free riders can maintain cooperation, but why individuals should engage in costly punishment is unclear. Solutions to this 'second-order free rider problem' include meta-punishment, mutation, conformism, signalling and group-selection. The threat of exclusion from indirect reciprocity can sustain collective action in the laboratory. Here, we show that such exclusion is evolutionarily stable, providing an incentive to engage in costly cooperation, while avoiding the second-order free rider problem because punishers can withhold help from free riders without damaging their reputations. However, we also show that such a strategy cannot invade a population in which indirect reciprocity is not linked to collective action, thus leaving unexplained how collective action arises.     

The efficient interaction of indirect reciprocity and costly punishment

Human cooperation in social dilemmas challenges researchers from various disciplines. Here we combine advances in experimental economics and evolutionary biology that separately have shown that costly punishment and reputation formation, respectively, induce cooperation in social dilemmas. The mechanisms of punishment and reputation, however, substantially differ in their means for 'disciplining' non-cooperators. Direct punishment incurs salient costs for both the punisher and the punished, whereas reputation mechanisms discipline by withholding action, immediately saving costs for the 'punisher'. Consequently, costly punishment may become extinct in environments in which effective reputation building--for example, through indirect reciprocity--provides a cheaper and powerful way to sustain cooperation. Unexpectedly, as we show here, punishment is maintained when a combination with reputation building is available, however, at a low level. Costly punishment acts are markedly reduced although not simply substituted by appreciating reputation. Indeed, the remaining punishment acts are concentrated on free-riders, who are most severely punished in the combination. When given a choice, subjects even prefer a combination of reputation building with costly punishment. The interaction between punishment and reputation building boosts cooperative efficiency. Because punishment and reputation building are omnipresent interacting forces in human societies, costly punishing should appear less destructive without losing its deterring force.     

Volunteering leads to rock-paper-scissors dynamics in a public goods game

Collective efforts are a trademark of both insect and human societies. They are achieved through relatedness in the former and unknown mechanisms in the latter. The problem of achieving cooperation among non-kin has been described as the 'tragedy of the commons', prophesying the inescapable collapse of many human enterprises. In public goods experiments, initial cooperation usually drops quickly to almost zero. It can be maintained by the opportunity to punish defectors or the need to maintain good reputation. Both schemes require that defectors are identified. Theorists propose that a simple but effective mechanism operates under full anonymity. With optional participation in the public goods game, 'loners' (players who do not join the group), defectors and cooperators will coexist through rock-paper-scissors dynamics. Here we show experimentally that volunteering generates these dynamics in public goods games and that manipulating initial conditions can produce each predicted direction. If, by manipulating displayed decisions, it is pretended that defectors have the highest frequency, loners soon become most frequent, as do cooperators after loners and defectors after cooperators. On average, cooperation is perpetuated at a substantial level.     

2000-2011安徽省社会保障水平适度性分析

社会保障制度属于公共资源在公共领域中的分配,具有一定的公共物品属性。其作为一种公共产品资源同样存在着适度性问题,社会保障水平是反映一个国家或地区经济发展和人民生活水平的重要指标。     

Evolution of indirect reciprocity

Natural selection is conventionally assumed to favour the strong and selfish who maximize their own resources at the expense of others. But many biological systems, and especially human societies, are organized around altruistic, cooperative interactions. How can natural selection promote unselfish behaviour? Various mechanisms have been proposed, and a rich analysis of indirect reciprocity has recently emerged: I help you and somebody else helps me. The evolution of cooperation by indirect reciprocity leads to reputation building, morality judgement and complex social interactions with ever-increasing cognitive demands.     

Evolution of cooperation without reciprocity.

A long-standing problem in biological and social sciences is to understand the conditions required for the emergence and maintenance of cooperation in evolving populations. For many situations, kin selection is an adequate explanation, although kin-recognition may still be a problem. Explanations of cooperation between non-kin include continuing interactions that provide a shadow of the future (that is, the expectation of an ongoing relationship) that can sustain reciprocity, possibly supported by mechanisms to bias interactions such as embedding the agents in a two-dimensional space or other context-preserving networks. Another explanation, indirect reciprocity, applies when benevolence to one agent increases the chance of receiving help from others. Here we use computer simulations to show that cooperation can arise when agents donate to others who are sufficiently similar to themselves in some arbitrary characteristic. Such a characteristic, or 'tag', can be a marking, display, or other observable trait. Tag-based donation can lead to the emergence of cooperation among agents who have only rudimentary ability to detect environmental signals and, unlike models of direct or indirect reciprocity, no memory of past encounters is required.     

合作进化模型综述

作者综述了合作进化模型的最新研究成果。合作进化模型以“囚徒困境”博弈模型为基础, 为合作中的个体提供了一种与个体本身无关的策略优化机制, 以此探讨合作策略能够稳定进化的条件。基于直接或间接互惠理论的合作进化模型验证了在小规模社会中建立声誉机制有助于实现稳定的互惠合作; 互惠可以看做是对合作行为的奖赏, 开放的社会网络有助于实现较大范围内的合作; 对非合作行为实施惩罚有助于实现多人合作, 在一定条件下, 由非合作者实施惩罚时的合作进化相较于由合作者实施时更稳定; 群组竞争有利于合作文化或制度的传播, 但无法解释群组融合后的合作问题。     

基于二阶声誉测度的自组织网络合作激励机制

将二阶声誉测度Standing应用到自组织网络的合作激励机制中,设计了一种基于Standing的包括服务和声誉管理的分布式合作管理协议,克服了间接互惠所面临的二阶搭便车问题.数学分析和模拟实验表明,在二阶声誉作用下,区分策略是演化博弈惟一的进化稳定策略,从而促进了用户的合作.同时,采用完全的分布方式所构建的可信第三方架构能够有效应对合谋、虚假的声誉反馈与声誉提供等欺骗行为.该合作机制在一般的动态环境中具有良好的适应性.     

矫正社会组织的发展对策研究——基于帕森斯AGIL系统模型的阐释

社会力量的参与是社区矫正的共性依赖，社会力量参与社区矫正存在多种方式。依据公共产品理论，矫正社会组织是社会力量参与社区矫正的最优方式之一。目前，矫正社会组织存在着资源短缺、目标单一且偏离、管理制度不健全、组织维持能力孱弱等四个方面的问题。文章试图通过帕森斯AGIL系统模型，提出发展矫正社会组织的具体对策。     

从地方治理角度看德国乡村公共物品供给体制

当前,农村公共物品的供给已成为众多学者关注的问题.本文从地方治理的角度出发,通过对地方治理理论的介绍,进而介绍分析了德国乡村公共物品供给体制在权责划分、法律规范、财政供给、监督制约及社会补充方面的特点,从而希望对我国农村公共物品供给的实践提供一些经验借鉴.     

城市交通拥挤机理的经济解析

运用经济学的理论和方法对大城市交通拥挤的机理进行剖析，认为城市交通拥挤与开发商追求土地区位巨大的级差效益有关；从微观经济学的角度分析了道路交通设施作为公用物品的外部效应导致拥挤的必然发生；最后，运用博弈论的基本方法对交通拥挤问题及涉及交通问题的对策进行了分析．     

Variation in behaviour promotes cooperation in the Prisoner's Dilemma game

The Prisoner's Dilemma game is widely used to investigate how cooperation between unrelated individuals can evolve by natural selection. In this game, each player can either 'cooperate' (invest in a common good) or 'defect' (exploit the other's investment). If the opponent cooperates, you get R if you cooperate and T if you defect. If the opponent defects, you get S if you cooperate and P if you defect. Here T > R > 0 and P > S, so that 'defect' is the best response to any action by the opponent. Thus in a single play of the game, each player should defect. In our game, a fixed maximum number of rounds of the Prisoner's Dilemma game is played against the same opponent. A standard argument based on working backwards from the last round shows that defection on all rounds is the only stable outcome. In contrast, we show that if extrinsic factors maintain variation in behaviour, high levels of co-operation are stable. Our results highlight the importance of extrinsic variability in determining the outcome of evolutionary games.     

“互联网＋”环境下社会组织三方协同监管的演化博弈研究

“互联网＋”环境促进了社会组织的快速发展，但也对社会组织的监管提出了更大的挑战.在社会组织三方协同监管中，通过引入社会公众参与率、网络舆情影响度、声誉收益、处罚等变量，构建了社会组织、第三方评估机构和政府部门的三方演化博弈模型，分析了影响各博弈方策略选择与演化的因素，给出了三方演化博弈策略趋于稳定的条件，最后利用Matlab对演化博弈中的理想稳定状态进行了仿真.研究结果表明：在网络舆情影响度、声誉收益、政府部门的处罚等因素的影响下，当社会公众参与监管的水平较高时，即使政府部门放松监管，社会组织也会倾向于选择合规行为策略，第三方评估机构倾向于选择真实评估策略；当社会公众参与监管的水平较低时，任何一方的策略演化趋势都与另外两方的策略选择有关.为此，提出通过提升社会组织信息化水平，建立和完善声誉机制、奖惩机制和参与机制，形成社会组织多元协同监管体系，将有助于社会组织的健康有序发展.     

基于博弈分析的图书馆资源共享研究

图书馆是社会中最大形式的公用物品。阐述了公用物品的特征以及反映在公用物品上的博弈问题,探讨了实现公用图书馆投资多元化的措施,分析了基于博弈理论的联合采购及文献共享,指出图书馆实现资源共享的目标需要多方的努力和配合,需要广大读者及社会的支持。     

公众人物名誉权的保护

我国名誉权法律保护存在着言论自由和公众人物名誉权保护的协调问题。合理界定公众人物名誉权保护的范围与边界是化解公众人物名誉权保护困难的出发点。加强公众人物名誉权的保护需要明确引入公众人物的法律概念,建立我国公众人物名誉权保护的强化机制,引进西方的"惩罚性赔偿"制度、"恶意不实诉讼"制度和"实际恶意原则"。同时,公众人物的名誉权的保护也应受到合理的限制,国家需要制定新闻法以及相关法律保障言论自由和舆论监督。     

浅析苏联的消费品短缺问题

“苏联式社会主义经济”与“纯粹市场经济”的关键区别在于资源所有权和资源配置决策机制不同。苏联的经济资源由国家所有或控制,有关资源配置的决策由国家直接作出并带有法律效力。为保证重工业的高速增长,苏联政府减少并抑制社会消费需求,把资源集中到重工业部门,导致消费品供应紧张。为解决消费品短缺与社会需求增加的矛盾,政府一方面实行必需品“定量配给,”另一方面通过提高“周转税”的办法,剥夺新的需求,化解、弥合供求脱节并维持特权阶层的特殊供应。     

公共物品理论研究的范式演变:从需求到供给

源于威克塞尔-林达尔-萨缪尔森传统的标准公共物品理论范式着眼于需求侧的分析,由于搭便车的普遍存在和公共选择机制的固有缺陷,公共物品供给问题难以解决。通过范式转换,即着眼于异化不同个体对公共物品供给量的影响,加总技术视角的公共物品自愿供给理论可以拓展公共物品的分析框架。于是,该文作者考察了不同加总技术的公共物品分类及其对公共物品供给量的影响,在此基础上进行了简要评述和展望。     

基于公共物品提供对策的无限网格上的策略互动及其结构性均衡

基于公共物品提供对策的策略互动模型,在无限平面网格环境下研究考察均衡状态得以实现的条件、结构性均衡的种类以及其中提供公共物品参与者的最小比例等问题。主要贡献是确定了若干种类结构性均衡网格的结构并证明了结构性均衡网络中提供公共物品参与者的最小比例为20%。从网络对策理论的层面对于整体稳定的社会、经济网络中某些无序竞争或对立状态的出现提供了阐释。     

财政支出与城镇化：非线性机制的理论与实证研究

文章通过资源配置模型，分析了公共产品供给对城镇人口规模扩张的影响，提出了财政支出推动城镇化的非线性机制假说。实证结果确定了非线性机制的存在：财政支出增加公共产品供给，在一定条件下有利于推动城镇化进程；而人均财政支出水平的提高，不一定推动城镇化率提高。实证结果还揭示：人口结构和产出结构对城镇化的影响为正，但不显著。因此，在推动城镇化过程中，财政支出政策既要保持增量规模，又要优化支出结构。