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.     

Evolution of novel cooperative swarming in the bacterium Myxococcus xanthus

Cooperation among individuals is necessary for evolutionary transitions to higher levels of biological organization. In such transitions, groups of individuals at one level (such as single cells) cooperate to form selective units at a higher level (such as multicellular organisms). Though the evolution of cooperation is difficult to observe directly in higher eukaryotes, microorganisms do offer such an opportunity. Here we report the evolution of novel cooperative behaviour in experimental lineages of the bacterium Myxococcus xanthus. Wild-type strains of M. xanthus exhibit socially dependent swarming across soft surfaces by a mechanism known as 'S-motility' that requires the presence of extracellular type IV pili. In lineages of M. xanthus unable to make pili, a new mechanistic basis for cooperative swarming evolved. Evolved swarming is mediated, at least in part, by enhanced production of an extracellular fibril matrix that binds cells-and their evolutionary interests-together. Though costly to individuals, fibril production greatly enhanced population expansion in groups of interconnected cells. These results show that fundamental transitions to primitive cooperation can readily occur in bacteria.     

The nature of human altruism

Some of the most fundamental questions concerning our evolutionary origins, our social relations, and the organization of society are centred around issues of altruism and selfishness. Experimental evidence indicates that human altruism is a powerful force and is unique in the animal world. However, there is much individual heterogeneity and the interaction between altruists and selfish individuals is vital to human cooperation. Depending on the environment, a minority of altruists can force a majority of selfish individuals to cooperate or, conversely, a few egoists can induce a large number of altruists to defect. Current gene-based evolutionary theories cannot explain important patterns of human altruism, pointing towards the importance of both theories of cultural evolution as well as gene-culture co-evolution.     

Self-destructive cooperation mediated by phenotypic noise

In many biological examples of cooperation, individuals that cooperate cannot benefit from the resulting public good. This is especially clear in cases of self-destructive cooperation, where individuals die when helping others. If self-destructive cooperation is genetically encoded, these genes can only be maintained if they are expressed by just a fraction of their carriers, whereas the other fraction benefits from the public good. One mechanism that can mediate this differentiation into two phenotypically different sub-populations is phenotypic noise. Here we show that noisy expression of self-destructive cooperation can evolve if individuals that have a higher probability for self-destruction have, on average, access to larger public goods. This situation, which we refer to as assortment, can arise if the environment is spatially structured. These results provide a new perspective on the significance of phenotypic noise in bacterial pathogenesis: it might promote the formation of cooperative sub-populations that die while preparing the ground for a successful infection. We show experimentally that this model captures essential features of Salmonella typhimurium pathogenesis. We conclude that noisily expressed self-destructive cooperative actions can evolve under conditions of assortment, that self-destructive cooperation is a plausible biological function of phenotypic noise, and that self-destructive cooperation mediated by phenotypic noise could be important in bacterial pathogenesis.     

Cooperation and competition in pathogenic bacteria

Explaining altruistic cooperation is one of the greatest challenges for evolutionary biology. One solution to this problem is if costly cooperative behaviours are directed towards relatives. This idea of kin selection has been hugely influential and applied widely from microorganisms to vertebrates. However, a problem arises if there is local competition for resources, because this leads to competition between relatives, reducing selection for cooperation. Here we use an experimental evolution approach to test the effect of the scale of competition, and how it interacts with relatedness. The cooperative trait that we examine is the production of siderophores, iron-scavenging agents, in the pathogenic bacterium Pseudomonas aeruginosa. As expected, our results show that higher levels of cooperative siderophore production evolve in the higher relatedness treatments. However, our results also show that more local competition selects for lower levels of siderophore production and that there is a significant interaction between relatedness and the scale of competition, with relatedness having less effect when the scale of competition is more local. More generally, the scale of competition is likely to be of particular importance for the evolution of cooperation in microorganisms, and also the virulence of pathogenic microorganisms, because cooperative traits such as siderophore production have an important role in determining virulence.     

Monkeys reject unequal pay

During the evolution of cooperation it may have become critical for individuals to compare their own efforts and pay-offs with those of others. Negative reactions may occur when expectations are violated. One theory proposes that aversion to inequity can explain human cooperation within the bounds of the rational choice model, and may in fact be more inclusive than previous explanations. Although there exists substantial cultural variation in its particulars, this 'sense of fairness' is probably a human universal that has been shown to prevail in a wide variety of circumstances. However, we are not the only cooperative animals, hence inequity aversion may not be uniquely human. Many highly cooperative nonhuman species seem guided by a set of expectations about the outcome of cooperation and the division of resources. Here we demonstrate that a nonhuman primate, the brown capuchin monkey (Cebus apella), responds negatively to unequal reward distribution in exchanges with a human experimenter. Monkeys refused to participate if they witnessed a conspecific obtain a more attractive reward for equal effort, an effect amplified if the partner received such a reward without any effort at all. These reactions support an early evolutionary origin of inequity aversion.     

中美电信管制比较研究

由分析比较中美两国电信管制发现：不仅美国电信管制先进独到，有很多可学习之处，如管制独立，监督到位，管制设计和操作中充分体现造福于民、公平正义的人文精神；而且中国电信管制也有很多可取之处，如设立符合国情的管制机构，监管客观，督导及时，管制机构和政府的有机配合，市场有序竞争等，由此增强继续深化电信管制改革的信心和决心。     

Evolution and maintenance of cooperation via inheritance of neighborhood relationship

Cooperative behaviors are ubiquitous in nature and human society. It is very important to understand the internal mechanism of emergence and maintenance of cooperation. As we know now, the offsprings inherit not only the phenotype but also the neighborhood relationship of their parents. Some recent research results show that the interactions among individuals facilitate survival of cooperation through network reciprocity of clustering cooperators. This paper aims at introducing an inheritance mechanism of neighborhood relationship to explore the evolution of cooperation. In detail, a mathematical model is proposed to characterize the evolutionary process with the above inheritance mechanism. Theoretical analysis and numerical simulations indicate that high-level cooperation can emerge and be maintained for a wide variety of cost-to-benefit ratios, even if mutation happens during the evolving process.     

Reputation helps solve the 'tragedy of the commons'.

The problem of sustaining a public resource that everybody is free to overuse-the 'tragedy of the commons'-emerges in many social dilemmas, such as our inability to sustain the global climate. Public goods experiments, which are used to study this type of problem, usually confirm that the collective benefit will not be produced. Because individuals and countries often participate in several social games simultaneously, the interaction of these games may provide a sophisticated way by which to maintain the public resource. Indirect reciprocity, 'give and you shall receive', is built on reputation and can sustain a high level of cooperation, as shown by game theorists. Here we show, through alternating rounds of public goods and indirect reciprocity games, that the need to maintain reputation for indirect reciprocity maintains contributions to the public good at an unexpectedly high level. But if rounds of indirect reciprocation are not expected, then contributions to the public good drop quickly to zero. Alternating the games leads to higher profits for all players. As reputation may be a currency that is valid in many social games, our approach could be used to test social dilemmas for their solubility.     

Emergence of cooperation and evolutionary stability in finite populations

To explain the evolution of cooperation by natural selection has been a major goal of biologists since Darwin. Cooperators help others at a cost to themselves, while defectors receive the benefits of altruism without providing any help in return. The standard game dynamical formulation is the 'Prisoner's Dilemma', in which two players have a choice between cooperation and defection. In the repeated game, cooperators using direct reciprocity cannot be exploited by defectors, but it is unclear how such cooperators can arise in the first place. In general, defectors are stable against invasion by cooperators. This understanding is based on traditional concepts of evolutionary stability and dynamics in infinite populations. Here we study evolutionary game dynamics in finite populations. We show that a single cooperator using a strategy like 'tit-for-tat' can invade a population of defectors with a probability that corresponds to a net selective advantage. We specify the conditions required for natural selection to favour the emergence of cooperation and define evolutionary stability in finite populations.     

一种基于PSO思想的改进量子遗传算法

文章提出一种基于PSO思想的改进量子遗传算法.将PSO中的合作机制和记忆功能引入到QGA中,构造种群个体与当前最优解的距离参量,根据每个个体与当前最优解距离大小智能地控制旋转角的大小,使旋转角能够根据个体的进化差异选择不同旋转角的自适应调整进化过程,从而使算法始终保持合适的搜索网格,加快算法收敛,同时也可以保证能够收敛...     

Altruistic punishment in humans.

Human cooperation is an evolutionary puzzle. Unlike other creatures, people frequently cooperate with genetically unrelated strangers, often in large groups, with people they will never meet again, and when reputation gains are small or absent. These patterns of cooperation cannot be explained by the nepotistic motives associated with the evolutionary theory of kin selection and the selfish motives associated with signalling theory or the theory of reciprocal altruism. Here we show experimentally that the altruistic punishment of defectors is a key motive for the explanation of cooperation. Altruistic punishment means that individuals punish, although the punishment is costly for them and yields no material gain. We show that cooperation flourishes if altruistic punishment is possible, and breaks down if it is ruled out. The evidence indicates that negative emotions towards defectors are the proximate mechanism behind altruistic punishment. These results suggest that future study of the evolution of human cooperation should include a strong focus on explaining altruistic punishment.     

基于遗传算法的人工生命演示系统设计

讨论了人工生命仿真模型的建立方法 ,给出了一个基于遗传算法的人工生命模型及其演示系统的实现 .计算和考察了虚拟环境中生物在进化过程中的演变规律和涌现特征 ,模拟和解释了一些简单的生态行为和进化规律 ,如竞争、协作进化、群居、物种灭绝等现象 .这种通过进化的方法进行系统复杂性模拟的思想 ,对于研究认知进化和群体智能具有一定的参照意义     

长三角区域科技协同创新发展研究——基于区域间论文和专利合作

长三角科技协同创新对长三角高质量一体化具有重要的支撑作用,该文利用长三角地区之间创新合作的数据构建区域科技协同创新指标,主要采用地区之间论文和专利合作的数据,分析长三角地区间科技协同创新时空演变特征.研究发现：1) 长三角区域科技协同创新指数基本呈现波动中上升的态势,且程度在逐步加深.2) 长三角区域创新合作网络化趋势明显,且正在从单中心的合作网络转变为多中心的合作网络.核心城市往往在多个细分领域具有比较优势,但非核心城市优势往往聚焦于某个领域.3) 长三角其他三省依托上海的优势创新资源进行创新,上海的创新外溢促进了长三角地区的专利合作.4) 论文合作度增长较快,主要是由高质量的一区论文合作增长为主,对于长三角一体化高质量发展可以起到巨大的推动作用.从区域之间的比较来看,可以看出江浙沪三个地区的合作较为紧密,而安徽省与其他地区的合作程度较低.5) 长三角的创新合作主要可能仍以横向合作为主,其中论文合作以横向合作为主,专利合作以纵向合作为主.6) 长三角一体化扩容对区域协同创新具有显著的促进作用,并且对高质量的发明专利影响更大.     

Long-term vocal recognition in the northern fur seal

The ability to recognize and remember individual identities for long periods of time has important implications for the evolution of animal social behaviour, particularly complex interactions such as cooperation or mate choice. Despite this importance, there is only a single example of long-term individual recognition in nature, the 8-month retention of neighbour's song among male hooded warblers, Wilsonia citrina, and there is none for a non-human mammal. Associations between individuals spanning years, which are especially prevalent in carnivores, primates and seabirds, and evidence of mate fidelity provide indirect support for the ability of long-term recognition. In many of these instances, however, individuals do not separate for extended periods, and thus long-term recognition, although often assumed, may be both unnecessary and nonexistent. Furthermore, site fidelity rather than individual recognition may explain many instances of mate fidelity. Here I show that mother-offspring pairs of a migratory otariid pinniped--the northern fur seal (Callorhinus ursinus)--not only have the ability to recognize each other's vocalizations during the course of a breeding season, but are also able to retain these memories for at least 4 years.     

把握战略机遇 加强中欧科技合作

近年来中欧科技合作发展迅猛,在我国重要战略机遇期,认真分析中欧科技合作现状,总结科技合作实践经验,积极挖掘合作潜力,对我国制定科学的科技合作政策,全面提升国家创新科技体系,持续增进我国的科技优势,进而促进中国社会经济的全面发展而意义重大。     

Altruism through beard chromodynamics

The evolution of altruism, a behaviour that benefits others at one's own fitness expense, poses a darwinian paradox. The paradox is resolved if many interactions are with related individuals so that the benefits of altruism are reaped by copies of the altruistic gene in other individuals, a mechanism called kin selection. However, recognition of altruists could provide an alternative route towards the evolution of altruism. Arguably the simplest recognition system is a conspicuous, heritable tag, such as a green beard. Despite the fact that such genes have been reported, the 'green beard effect' has often been dismissed because it is unlikely that a single gene can code for altruism and a recognizable tag. Here we model the green beard effect and find that if recognition and altruism are always inherited together, the dynamics are highly unstable, leading to the loss of altruism. In contrast, if the effect is caused by loosely coupled separate genes, altruism is facilitated through beard chromodynamics in which many beard colours co-occur. This allows altruism to persist even in weakly structured populations and implies that the green beard effect, in the form of a fluid association of altruistic traits with a recognition tag, can be much more prevalent than hitherto assumed.     

国内外知识型产业间相互作用关系数理分析

为研究国内外知识型产业的相互作用关系,采用生态学中的Lotka-Voterra方程研究了竞争、合作及协同作用下国外知识型企业进入对国内知识型产业的影响.数理分析表明:国外知识型产业进入造成的过度竞争压力将导致国内、外知识型产业发展的负协变关系,并将导致竞争力相对较弱的国内知识型产业的衰退;适度合作关系则使国内、外知识型产业发展呈现正协变关系,并实现稳定共生;而协同作用将使二者的共生稳定点不仅优于竞争关系下的稳定点,而且帕累托优于合作关系下的稳定点,并能扩展产业的企业容量.     

大学生学习状况调查及其与社会情感的关系

目前大学生学习存在着学习动机缺失、对师生教学活动中情感交流的迫切需求、学生间学习合作能力欠缺等三方面问题,形成这些问题的深层次因素是大学生某些社会情感的缺乏,而解决这些现存学习问题的办法主要有：从社会情感教育入手,增强大学生的情感体验,激发学习动机;加强师生问的情感交流互动,拓展师生交流渠道;促进大学生间的学习合作,构建良好人际关系等。     

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.