From Local to Global Dilemmas in Social Networks

Social networks affect in such a fundamental way the dynamics of the population they support that the global, population-wide behavior that one observes often bears no relation to the individual processes it stems from. Up to now, linking the global networked dynamics to such individual mechanisms has remained elusive. Here we study the evolution of cooperation in networked populations and let individuals interact via a 2-person Prisoner's Dilemma – a characteristic defection dominant social dilemma of cooperation. We show how homogeneous networks transform a Prisoner's Dilemma into a population-wide evolutionary dynamics that promotes the coexistence between cooperators and defectors, while heterogeneous networks promote their coordination. To this end, we define a dynamic variable that allows us to track the self-organization of cooperators when co-evolving with defectors in networked populations. Using the same variable, we show how the global dynamics — and effective dilemma — co-evolves with the motifs of cooperators in the population, the overall emergence of cooperation depending sensitively on this co-evolution

The Role of Clusters in Knowledge Creation and Diffusion – an Institutional Perspective

Clusters and networks have received renewed attention in recent years not only as a tool for regional development in general but as an institution of knowledge creation and diffusion between the knowledge infrastructure of a region and the firms within the clusters. They are therefore often regarded as geographically condensed forms of economic cooperation and knowledge exchange. The recent renaissance of interest in institutions as a factor shaping economic performance has therefore also implications for the creation and sustained existence of clusters and networks as a tool for knowledge management and as learning organisations within and across regions. This institutional perspective serves to identify additional factors influencing economic behaviour leading to cooperation. Different strands of institutional thinking –institutions as “social technologies” in the tradition of evolutionary economics, clusters as a form of Coase institution integrating positive external effects of technological knowledge, the importance of knowledge sharing in the context of the “New Institutional Economics” – emphasize that connectivity cannot be effectively coordinated by conventional markets. Clusters and networks are among the non-market devices by which firms seek to coordinate their activities with other firms and other knowledge-generating institutions. But it is also important to emphasize that clusters as coordinating institutions are not automatically just there but that they are the result of an evolving process shaped by policy activities and entrepreneurial behaviour responding to new challenges. Clusters as social technologies are co-evolving with new physical technologies and are therefore in constant need to change themselves. They can be regarded as an answer to the problems of achieving agreement and coordination in a context where there is a collective interest. They combine different additional elements that are important for regional development and economic growth.

Evolution of cooperation in synergistically evolving dynamic interdependent networks: Fundamental advantages of coordinated network evolution

© 2019 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft. Real networks are not only multi-layered yet also dynamic. The role of coordinated network evolution regarding dynamic multi-layer networks where both network and strategy evolution simultaneously show diverse interdependence by layers remains poorly addressed. Here, we propose a general and simple coevolution framework to analyze how coordination of different dynamical processes affects strategy propagation in synergistically evolving interdependent networks. The strategic feedback constitutes the main driving force of network evolution yet the inherent cross-layer self-optimization functions as its compensation. We show that these two ingredients often catalyze a better performance of network evolution in propagating cooperation. Coordinated network evolution may be a double-edged sword to cooperation and the network-Adapting rate plays a crucial role in flipping its double-sided effect. It often economizes the cost and time consumption for driving the system to the full cooperation phase. Importantly, strongly coupled slow-Tuned networks can outperform weakly coupled fast-regulated networks in solving social dilemmas, highlighting the fundamental advantages of coordinated network evolution and the importance of synergistic effect of dynamical processes in upholding human cooperation in multiplex networks

Evolution of cooperation in multilayer networks

Dissertation presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Information Systems and Technologies ManagementIndividuals take part in multiple layers of networks of interactions simultaneously. These interdependent networks account for the different sort of social ties individuals maintain per layer. In each layer individuals participate in N-Player Public Goods Games where benefits collected increase with amounts invested. It is, however, tempting to be a free-rider, i.e., to take advantage of the common pool without contributing to it, a situation from which a social dilemma results. This thesis offers new insights on how cooperation dynamics is shaped by multiple layers of social interactions and diversity of contributions invested per game. To this end, we resort to Evolutionary Game Theory and Network Science to provide a convenient framework to address the most important prototypical social conflicts and/or dilemmas in large networked populations. In particular, we propose a novel mean-field approach capable of tracking the self-organization of Cooperators when co-evolving with Defectors in a multilayer environment. We show that the emerging collective dynamics, which depends (i) on the underlying layer networks of interactions and (ii) on the criteria to share a finite investment across all games, often does not bear any resemblance with the local processes supporting them. Our findings suggest that, whenever individual investments are distributed among games or layers, resilience of cooperation against free-riders increases with the number of layers, and that cooperation emerges from a non-trivial organization of cooperation across the layers. In opposition, under constant, non-distributed investments, the level of cooperation shows little sensibility to variations in the number of layers. These findings put in evidence the importance of asymmetric contributions across games and social contexts in the emergence of human cooperation

Assortative Mixing Equilibria in Social Network Games

It is known that individuals in social networks tend to exhibit homophily (a.k.a. assortative mixing) in their social ties, which implies that they prefer bonding with others of their own kind. But what are the reasons for this phenomenon? Is it that such relations are more convenient and easier to maintain? Or are there also some more tangible benefits to be gained from this collective behaviour? The current work takes a game-theoretic perspective on this phenomenon, and studies the conditions under which different assortative mixing strategies lead to equilibrium in an evolving social network. We focus on a biased preferential attachment model where the strategy of each group (e.g., political or social minority) determines the level of bias of its members toward other group members and non-members. Our first result is that if the utility function that the group attempts to maximize is the degree centrality of the group, interpreted as the sum of degrees of the group members in the network, then the only strategy achieving Nash equilibrium is a perfect homophily, which implies that cooperation with other groups is harmful to this utility function. A second, and perhaps more surprising, result is that if a reward for inter-group cooperation is added to the utility function (e.g., externally enforced by an authority as a regulation), then there are only two possible equilibria, namely, perfect homophily or perfect heterophily, and it is possible to characterize their feasibility spaces. Interestingly, these results hold regardless of the minority-majority ratio in the population. We believe that these results, as well as the game-theoretic perspective presented herein, may contribute to a better understanding of the forces that shape the groups and communities of our society

Detecting the Collapse of Cooperation in Evolving Networks

The sustainability of biological, social, economic and ecological communities is often determined by the outcome of social conflicts between cooperative and selfish individuals (cheaters). Cheaters avoid the cost of contributing to the community and can occasionally spread in the population leading to the complete collapse of cooperation. Although such collapse often unfolds unexpectedly, it is unclear whether one can detect the risk of cheater’s invasions and loss of cooperation in an evolving community. Here, we combine dynamical networks and evolutionary game theory to study the abrupt loss of cooperation with tools for studying critical transitions. We estimate the risk of cooperation collapse following the introduction of a single cheater under gradually changing conditions. We observe an increase in the average time it takes for cheaters to be eliminated from the community as the risk of collapse increases. We argue that such slow system response resembles slowing down in recovery rates prior to a critical transition. In addition, we show how changes in community structure reflect the risk of cooperation collapse. We find that these changes strongly depend on the mechanism that governs how cheaters evolve in the community. Our results highlight novel directions for detecting abrupt transitions in evolving networks

Cooperation in anonymous dynamic social networks

Abstract We study the extent to which cooperative behavior can be sustained in large, anonymous, evolving social networks. Individuals strategically form relationships under a social matching protocol and engage in prisoner's dilemma interactions with their partners. We characterize a class of equilibria that support cooperation as a stationary outcome. When cooperation is possible, its level is uniquely determined. While neither community enforcement nor contagion mechanisms have force in our setting, the endogenous dynamics of the social network imply that cooperation allows an individual to gradually accumulate a large network of profitable interactions, while defection results in social marginalization. Even as players become perfectly patient, equilibrium allows for full cooperation, only autarky, or the coexistence of cooperation and defection, depending on payoffs. Smaller levels of cooperation can be sustained by a form of exclusivity among cooperators. * We than

Coevolutionary games - a mini review

Prevalence of cooperation within groups of selfish individuals is puzzling in that it contradicts with the basic premise of natural selection. Favoring players with higher fitness, the latter is key for understanding the challenges faced by cooperators when competing with defectors. Evolutionary game theory provides a competent theoretical framework for addressing the subtleties of cooperation in such situations, which are known as social dilemmas. Recent advances point towards the fact that the evolution of strategies alone may be insufficient to fully exploit the benefits offered by cooperative behavior. Indeed, while spatial structure and heterogeneity, for example, have been recognized as potent promoters of cooperation, coevolutionary rules can extend the potentials of such entities further, and even more importantly, lead to the understanding of their emergence. The introduction of coevolutionary rules to evolutionary games implies, that besides the evolution of strategies, another property may simultaneously be subject to evolution as well. Coevolutionary rules may affect the interaction network, the reproduction capability of players, their reputation, mobility or age. Here we review recent works on evolutionary games incorporating coevolutionary rules, as well as give a didactic description of potential pitfalls and misconceptions associated with the subject. In addition, we briefly outline directions for future research that we feel are promising, thereby particularly focusing on dynamical effects of coevolutionary rules on the evolution of cooperation, which are still widely open to research and thus hold promise of exciting new discoveries.Comment: 24 two-column pages, 10 figures; accepted for publication in BioSystem

Different reactions to adverse neighborhoods in games of cooperation

In social dilemmas, cooperation among randomly interacting individuals is often difficult to achieve. The situation changes if interactions take place in a network where the network structure jointly evolves with the behavioral strategies of the interacting individuals. In particular, cooperation can be stabilized if individuals tend to cut interaction links when facing adverse neighborhoods. Here we consider two different types of reaction to adverse neighborhoods, and all possible mixtures between these reactions. When faced with a gloomy outlook, players can either choose to cut and rewire some of their links to other individuals, or they can migrate to another location and establish new links in the new local neighborhood. We find that in general local rewiring is more favorable for the evolution of cooperation than emigration from adverse neighborhoods. Rewiring helps to maintain the diversity in the degree distribution of players and favors the spontaneous emergence of cooperative clusters. Both properties are known to favor the evolution of cooperation on networks. Interestingly, a mixture of migration and rewiring is even more favorable for the evolution of cooperation than rewiring on its own. While most models only consider a single type of reaction to adverse neighborhoods, the coexistence of several such reactions may actually be an optimal setting for the evolution of cooperation.Comment: 12 pages, 5 figures; accepted for publication in PLoS ON