The Evolution of Cooperation in Structured Populations

The present paper analyses the evolution of costly cooperation in a multi-group population. Building on insights first developed in modern biology the idea of viscous population equilibria is introduced (a population is said to be viscous when a (sub)population of players is spatially or genetically clustered). A simple model then analyses how the combined effect of viscosity within multiple subgroups and different levels of between-group segregation influences the evolution of cooperation. The results suggest that a key issue in the evolution of cooperation is the shifting balance between the need to protect cooperators and propagation of the tendency to cooperate.     

Spatial Evolution of Social Norms in a Common-Pool Resource Game

We study the conditions for the emergence of cooperation in a spatial common-pool resource (CPR) game. We consider three types of agents: cooperators, defectors and enforcers. The role of enforcers is to punish defectors for overharvesting the resource. Agents are located on a circle and they only observe the actions of their two nearest neighbors. Their payoffs are determined by both local and global interactions and they modify their actions by imitating the strategy in their neighborhood with the highest average payoffs on average. Using theoretical and numerical analysis, we find a large diversity of equilibria to be the outcome of the game. In particular, we find conditions for the occurrence of equilibria in which the three strategies coexist. We also derive the stability of these equilibria. Finally, we show that introducing resource dynamics in the system favors the occurrence of cooperative equilibria.      

The collective action problem: Within-group cooperation and between-group competition in a repeated rent-seeking game

This paper analyzes the ability of group members to cooperate in rent-seeking activities in a context of between-group competition. For this purpose, we develop an infinitely repeated rent-seeking game between two groups of different size. We first investigate Nash reversion strategies to support cooperative behavior in both groups, before analyzing double-edge trigger strategies which support cooperation in one group only. These last strategies have the property that cheating on the agreement in the cooperative group is followed by non-cooperation in this group and cooperation in the rival group. The main conclusion is that the set of parameters for which cooperation can be sustained within the larger group as a subgame perfect outcome is as large as that for which cooperation can be sustained in the smaller group. Hence, in contrast to Olson?s (1965) celebrated thesis, but in accordance with many informal and formal observations, larger groups can be as effective as smaller groups in furthering their interests.     

Social context reveals gender differences in cooperative behavior

A number of previous researches indicate that men prefer competition over cooperation, and it is sometimes suggested that women show the opposite behavioral preference. In the current study the effects of social context on gender differences in cooperation are investigated. For the purpose, we compared men and women behavior under two social conditions: in groups of strangers and in groups with long-term socialization—groups of friends. The differences were found in changes in the level of cooperation, taking into account the effects of mixing social and gender variables. Social interaction and communication made cooperation of group members strength and sustainable. However, men’s and women’s cooperative behavior in groups differed. Women were initially more inclined to cooperate in interaction with strangers. Men showed greater sensitivity to sociality effects. They tended to make cooperative decisions more often if there were friends in the group. Furthermore, men cooperated with previously unknown people after socialization with them significantly more than women.     

基于双网络视角的众创空间合作创新网络演化机制研究

众创空间逐渐成为当前研究热点,构建高效的合作创新网络可以提升其运营绩效。当前,合作创新网络解耦研究越来越多,对知识网络与合作网络交互关系进行研究能够更加完整地再现真实网络作用机理。基于双网络视角,对知识网络与合作网络进行解耦,探索众创空间运营机制与创业企业合作策略对网络创新绩效的影响,利用数理建模和仿真方法模拟众创空间知识网络与合作网络的动态演化结构以及两种网络间的交互作用,为提升众创空间运营效率提出改进建议。结果表明：企业合作关系断链重连概率对合作创新绩效有较大影响,这一概率存在相对合理区间;知识网络与合作网络结构在双网络结构机制下有较大差异,并且在动态演化过程中存在交互作用。     

Confusion and learning in the voluntary contributions game

We use a limited information environment to assess the role of confusion in the repeated voluntary contributions game. A comparison with play in a standard version of the game suggests, that the common claim that decision errors due to confused subjects biases estimates of cooperation upwards, is not necessarily correct. Furthermore, we find that simple learning cannot generate the kind of contribution dynamics commonly attributed to the existence of conditional cooperators. We conclude that cooperative behavior and its decay observed in public goods games is not a pure artefact of confusion and learning.     

Naive learning and cooperation in network experiments

In this paper we study learning and cooperation in repeated prisoners' dilemmas experiments. We compare interaction neighbourhoods of different size and structure, we observe choices under different information conditions, and we estimate parameters of a learning model.We find that naive imitation, although a driving force in many models of spatial evolution, may be negligible in the experiment. Naive imitation predicts more cooperation in spatial structures than in spaceless ones—regardless whether interaction neighbourhoods have the same or different sizes in both structures. We find that with some interaction neighbourhoods even the opposite may hold.     

THE EXPECTED NUMBER OF COOPERATORS IN THE N‐PERSON PRISONERS’ DILEMMA WITH RANDOM ORDER MOVES*

The present paper examines the possibility of cooperation occurring in the N‐person prisoners’ dilemma, played with randomly ordered moves and imperfect information. To take into account imperfect cooperation, the degree of cooperation is evaluated in terms of the expected number of cooperators. It is shown that: (i) the expected number of cooperators is maximized at an equilibrium, a combination of strategies each of which is a type of trigger strategy; (ii) the maximum expected number of cooperators is attained in a state of imperfect cooperation for a range of payoff functions; and (iii) the maximum expected number of cooperators is non‐decreasing when the size of players’ group increases.     

The effects of heterogeneous interaction and risk attitude adaptation on the evolution of cooperation

This paper addresses the evolution of cooperation in a multi-agent system with agents interacting heterogeneously with each other based on the iterated prisoner’s dilemma (IPD) game. The heterogeneity of interaction is defined in two models. First, agents in a network are restricted to interacting with only their neighbors (local interaction). Second, agents are allowed to adopt different IPD strategies against different opponents (discriminative interaction). These two heterogeneous interaction scenarios are different to the classical evolutionary game, in which each agent interacts with every other agent in the population by adopting the same strategy against all opponents. Moreover, agents adapt their risk attitudes while engaging in interactions. Agents with payoffs above (or below) their aspirations will become more risk averse (or risk seeking) in subsequent interactions, wherein risk is defined as the standard deviation of one-move payoffs in the IPD game. In simulation experiments with agents using only own historical payoffs as aspirations (historical comparison), we find that the whole population can achieve a high level of cooperation via the risk attitude adaptation mechanism, in the cases of either local or discriminative interaction models. Meanwhile, when agents use the population’s average payoff as aspirations (social comparison) for adapting risk attitudes, the high level of cooperation can only be sustained in a portion of the population (i.e., partial cooperation). This finding also holds true in both of the heterogeneous scenarios. Considering that payoffs cannot be precisely estimated in a realistic IPD game, simulation experiments are also conducted with a Gaussian disturbance added to the game payoffs. The results reveal that partial cooperation in the population under social comparison is more robust to the variation in payoffs than the global cooperation under historical comparison.     

How does the effect of pre-play suggestions vary with group size? Experimental evidence from a threshold public-good game

Numerous studies have examined factors influencing the likelihood of cooperative outcomes in nonzero-sum games, but there has been little study of the interaction between two of the most important: group size and pre-play cheap talk. We report results from an experiment in which groups of size between 2 and 15 play a one-shot multi-player threshold public-good game. In our random leader treatment, all group members select a suggestion (e.g., “Everyone should choose X”), with one randomly chosen to be broadcast to the group. In a choice only treatment, subjects choose suggestions but none is sent, and in a baseline treatment, there are no suggestions at all. We find a negative interaction between group size and this kind of communication: the beneficial effect of both suggestions overall and cooperative suggestions on cooperation, cooperative outcomes, and payoffs decreases sharply as the group size increases. We find a similar negative interaction in a follow-up treatment in which all group members’ suggestions are broadcast to the group. Our results suggest that care should be taken in generalising conclusions from small-group experiments to large groups.     

Dissertation abstract: Reputational benefits of altruism and altruistic punishment

Recent studies in experimental economics have shown that many people have other-regarding preferences, potentially including preferences for altruism, reciprocity, and fairness. It is useful to investigate why people possess such preferences and what functional purpose they might serve outside the laboratory, because evolutionary and social learning perspectives both predict that cooperative sentiments should only exist if they bring benefits that outweigh the costs of other-regarding behavior. Theories of costly signaling suggest that altruistic acts may function (with or without intention) as signals of unobservable qualities such as resources or cooperative intent, and altruists may benefit (possibly unintentionally) from the advertisement of such qualities. After reviewing the theories that could potentially account for the evolution of altruism (Chapter 1), I test some predictions about cooperation derived from costly signaling theory. In Chapter 2, I show that participants in experimental public goods games were more cooperative when they had cues that they could benefit from having a good reputation, and that there was apparently some competition to be the most generous group member. Furthermore, in subsequent trust games, people tended to trust high public goods contributors more than low contributors. Chapter 3 failed to find evidence that granting high status to people makes them more likely to contribute to public goods or punish free-riders, but there was suggestive evidence that physical proximity to the experimenter affected contributions and punishment. In Chapter 4, I found that people tended to trust others who were willing to incur costs to punish those who free-ride on group cooperation provided that such punishment was justified, and men were more punitive than women. In Chapter 5, I show that women find altruistic men more desirable than neutral men for long-term relationships. Together, these results suggest that humans do treat altruism as a signal of willingness to be cooperative. These findings are discussed with respect to the adaptive design of cooperative sentiments as well as the current debate over group selection. Dissertation: Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontarion Currently: Post-Doc, Department of Neurobiology & Behavior, Cornell University     

Agricultural innovation in less developed countries

We identify and elaborate some critical factors and mechanisms that foster the emergence of cooperative behavioral patterns. Through institutionalization, which solves social dilemmas through habituation, these factors and mechanisms provide the foundation of contingent cooperation and contextual trust in specific interaction ‘arenas’ and ‘meso’-sized ‘platforms’ (and related carrier groups) in these. This, then, may in turn support the emergence of general trust in the whole population, i.e., across all specific arenas and platforms. The emergence of institutions of cooperation may gain traction more easily in smaller arenas. This, and the transfer, spillover, or generalization to other arenas and platforms, is by no means determined, and the analytical foundation we offer permits to account for the different levels of cooperation, general trust, and socioeconomic performance observable in real-world economies (varieties of capitalisms). Directions of future research, as well as a policy focus, are provided as well.     

基于产学联合申请专利的合作网络动态演化研究

从社会网络视角,以1985-2016年产学联合申请并授权的专利数据为基础,运用社会网络分析方法,构建产学合作网络与跨区域合作网络,并分析合作主体的基本特征与合作网络动态演化过程。结果发现：中国产学合作模式从“一校-一企”向“多校-多企”转变,跨区域合作模式也从“一省-其它 一省”向“一省-其它-多省”演化,合作深度逐渐增加,但合作广度仍需进一步拓展;高校与企业在合作网络演化中相对稳定,参与合作的高校相对集中且多为综合性大学,企业合作集中在能源领域和高技术领域;“地理邻近”仍是制约产学合作的主要因素,总体上区域内合作数量占比依然大于跨区域合作;产学合作网络与跨区域合作网络具有显著的非对称性特征。     

营销渠道的冲突与协调研究——基于我国食品制造商和直接零售商合作博弈的实证分析

当渠道的非合作导致的冲突被逐渐认识到时,渠道成员就会有意识地开展合作。那么,合作是否确实减少了冲突,增进了协调呢？本文利用博弈理论提出六个假设,然后用现代计量方法进行实证检验,最后得出以下结论：渠道合作博弈优于非合作博弈,渠道成员间倾向于合作博弈,合作博弈下的营销渠道纵向成员（参与方）选择为地位相当者,渠道合作博弈中普遍存在隐性冲突,其程度与成员影响力的运用有关,合作博弈下的渠道成员普遍比较协调,营销渠道成员合作的协调及持续协调与诚信公平相关。     

Parallel experimentation: a basic scheme for dynamic efficiency

Evolutionary economics often focuses on the comparison between economic competition and the process of natural selection to select the fitter members of a given population. But that neglects the other “half” of an evolutionary process, the mechanism for the generation of new possibilities that is key to dynamic efficiency. My topic is the process of parallel experimentation which I take to be a process of multiple experiments running concurrently with some form of common goal, with some semi-isolation between the experiments, with benchmarking comparisons made between the experiments, and with the “migration” of discoveries between experiments wherever possible to ratchet up the performance of the group. The thesis is that parallel experimentation is a fundamental dynamic efficiency scheme to enhance and accelerate variation, innovation, and learning in contexts of genuine uncertainty or known ignorance. Within evolutionary biology, this type of parallel experimentation scheme was developed in Sewall Wright’s shifting balance theory of evolution. It addressed the rather neglected topic of how a population on a low fitness peak might eventually be able to go “downhill” against selective pressures, traverse a valley of low fitness, and then ascend a higher fitness peak. The theme of parallel experimentation is used to recast and pull together dynamic and pluralistic theories in economics, political theory, philosophy of science, and social learning.     

REACHING THE RURAL POOR THROUGH AGRICULTURAL COOPERATIVES IN MONGOLIA

This paper focuses on the cooperative sector in central Mongolia. Its aim is to provide new insights into the role and importance of cooperatives among poor rural populations. We analyse cooperatives’ inclusiveness of smaller herders and farmers and cooperatives’ governance structures. The research is based on data collected in selected provinces of the central Töv region. The data were collected for three distinctive target groups – cooperative board members, cooperative members and non‐members. We found that the cooperative sector in Mongolia is strongly affected by the governmental policy regarding wool subsidies, which provides subsidies only to cooperative members and has consequently caused rapid growth in the number of new, free‐riding cooperative members and led to very low levels of members’ self‐identification with their cooperatives. This policy also affects the inner organizational structures of cooperatives. Further, we found indications that poorer farmers tend not to be members of cooperatives and that the overall benefits for non‐members and the general community arising from local cooperatives are rather low.     

中韩新能源产业合作的经济效应实证研究

本文主要探讨中韩新能源领域的合作,尤其是对两国新能源领域中合作的经济效应进行评估。为了评价合作的经济效应,本文建立新能源合作的相对收益指数,并利用向量自回归模型(VAR)探寻能源合作指数(ECI)和贸易、GDP之间的关系,从而论证中韩新能源产业合作的重要性。     

基于科学计量的创新研究群体合作网络构型可视化分析

创新研究群体是受自然科学基金资助的我国基础研究前沿的高水平科研创新团队,分析并把握其结构特征与合作网络构型,有助于提升合作效率并促进原始创新。通过知识图谱可视化分析,发现并验证了优秀群体合作网络构型为晶格结构,具有较高的网络密度值,主要节点也具有较高的合作频次与中介中心性。基于科学计量的比较分析,发现了群体晶格结构具有单晶核辐射型与多（准）晶核均衡型两种形态,主要成员合作方式分别为主导型领军人物+追随型研究骨干与协调型领军人物+准晶核研究骨干,两类构型互有交织,只是在程度上有所差异。     

Sustaining cooperation in laboratory public goods experiments: a selective survey of the literature

I survey the literature post Ledyard (Handbook of Experimental Economics, ed. by J. Kagel, A. Roth, Chap. 2, Princeton, Princeton University Press, 1995) on three related issues in linear public goods experiments: (1) conditional cooperation; (2) the role of costly monetary punishments in sustaining cooperation and (3) the sustenance of cooperation via means other than such punishments. Many participants in laboratory public goods experiments are “conditional cooperators” whose contributions to the public good are positively correlated with their beliefs about the average group contribution. Conditional cooperators are often able to sustain high contributions to the public good through costly monetary punishment of free-riders but also by other mechanisms such as expressions of disapproval, advice giving and assortative matching.     

社会网络视角下联盟成员合作关系对技术标准形成的影响

技术标准联盟已成为各行业技术标准形成与产业化工作的重要主体，而技术标准形成的各项工作主要通过联盟成员间合作得以实施。因此，基于社会网络视角探究技术标准联盟成员合作关系对技术标准形成的影响很有必要。以技术源散性为中介变量，构建联盟成员合作关系对技术标准形成的影响机制模型，提出研究假设，然后绘制闪联标准联盟专利合作网络，并通过专利合作网络拓扑指标对研究假设进行实证检验。结果表明，联盟成员合作广度与技术标准形成之间存在U型关系，联盟成员合作深度能够促进技术标准形成，技术源散性在联盟成员合作关系与技术标准形成之间存在部分中介作用。