A tragedy of the commons, in which rational behavior of individuals to maximize their own payoffs depletes common resources, is one of the most important research topics in game theory. To better understand the social dilemma problem, recent studies have developed a theoretical framework of feedback-evolving game where individual behavior affects an environmental (renewable) resource and the environmental resource changes individual payoffs. While previous studies assumed that the frequency of defectors increases (prisoner's dilemma [PD] game) when the environmental resource is abundant to investigate an oscillating tragedy of the commons, it is also possible for other types of game to produce the social dilemma. In this paper, we extend the feedback-evolving game by considering not only PD game, but also the other three game structures when the environmental resource is replete for a reasonably complete classification. The three games are Chicken game where defectors and cooperators coexist through minority advantage, Stag-Hunt (SH) game with minority disadvantage, and Trivial game where the frequency of cooperators increases. In addition, we utilize a dilemma phase plane to visually track (transient) dynamics of game structure changes. We found that an emergent initial condition dependence (i.e. bistability) is pervasive in the feedback-evolving game when the three games are involved. We also showed that persistent oscillation dynamics arise even with Chicken or SH games in replete environments. Our generalized analysis will be an important step to further extend the theoretical framework of feedback-evolving game to various game situations with environmental feedback.

Evolutionary theory is based on the conflict that arises when certain heritable variants out-compete others. Given this foundational conflict, a central question for evolutionary biologists concerns the presence of cooperation found throughout all levels of biological organization; from biochemical pathways to complex animal societies. Human behavior is often distinguished from other animal behavior by the presence of acts of cooperative behavior called altruism. Altruism is a cooperative act that penalizes the actor for actions that benefit the recipient. Any other form of cooperation, one that does not penalize the actor, is formally not considered altruistic. How can costly altruistic behavior evolve? This question was the basis for development of a web application tool incorporating a game theory model to investigate conditions affecting cooperative behavior. The game theory model described as Prisoner’s Dilemma incorporates acts of cooperation and non-cooperation (defection). Computer simulations of Prisoner’s Dilemma were developed and online applications were administered for five semesters at Georgia Gwinnett College, using two simulation environments referred to as Random and Non-random. Data collected from simulation runs were used to evaluate the effect of environment on student cooperative behavior and actively engage students in concepts associated with the evolution of cooperation and game theory. Results from student game play suggest group simulation environment played a significant role in the likelihood of observing cooperative behavior. Educational content and attitudinal surveys suggested that PD game play in the undergraduate evolution class at Georgia Gwinnett College improved student knowledge and self-confidence.

The outcome of the COP27 confirms the PD game nature of the work of this UN club, CUT defeated by EMIT (emissions). The same will hold for forward COPs, until such time that the tipping points change the game for the great players in this global environment club.

Co-evolution of cooperation with resource allocation in spatial multigame using switching control

Local norms and shared beliefs in cohesive social groups regulate individual behavior in everyday economic life. I use a door-to-door field experiment where a hundred and twenty villagers recruited from twenty-three communities in a Japanese rural mountainous village play a simultaneous prisoner’s dilemma game. To examine whether a set of experiences shared through interactions among community members affect experimental behavior, I compare villagers’ behavior under in-community and out-community random matching protocols. I also report a counterpart laboratory experiment with seventy-two university student subjects to address the external validity of laboratory experiments. The findings are three-fold. First, almost full cooperation is achieved when villagers play a prisoner’s dilemma game with their anonymous community members. Second, cooperation is significantly higher within the in-group compared to the out-group treatment in both the laboratory and field experiments. Third, although a significant treatment effect of social group membership is preserved, a big difference in the average cooperation rates is observed between the laboratory and field.

In network systems characterized by complex interactions of various types, core-periphery structures can be found. In this paper, we deal with such questions as what processes can lead to the emergence of core-periphery formation, whether this structure is symmetric, and to what extent. Namely, the question of symmetry in a complex network is still the subject of intense research interest. Symmetry can relate to network topology, network relationships, and other processes on networks. To answer these questions, we modified the model of the classic social dilemma called the repeated prisoner’s dilemma (or repeated PD game) by adding the cost of maintaining relationships between the pairs of players (partners) and especially by adding the possibility of ending some relationships. We present the results of simulations that suggest that the players’ network strategy (i.e., partner selection or termination of relationships with some partners) is the driving force behind the emergence of a core-periphery structure in networks rather than the player’s strategy in PD. Our results also suggest that the formed core is symmetric, and this symmetry is a result of the symmetric interactions of core players. Our outcomes can help understand various economic or social questions related to creating centers or peripheries, including their symmetry in different network systems.

m a g am e, Gaze behavior, Ag g ression

Free-riding produces inequality in the prisoners’ dilemma: cooperators suffer costs that defectors avoid, thus putting them at a material disadvantage to their anti-social peers. This inequality, accordingly, conveys information about a social partner’s choices in past game play and raises the possibility that agents can use the aggregation of past payoffs—i.e. wealth—to identify a social partner who uses their same strategy. Building on these insights, we study a computational model in which agents can employ a strategy—when playing multiple one-shot prisoners’ dilemma games per generation—in which they view other agents’ summed payoffs from previous games, choose to enter a PD game with the agent whose summed payoffs most-closely approximate their own, and then always cooperate. Here we show that this strategy of wealth homophily—labelled COEQUALS (“CO-operate with EQUALS”)—can both invade an incumbent population of defectors and resist invasion. The strategy succeeds because wealth homophily leads agents to direct cooperation disproportionately toward others of their own type—a phenomenon known as “positive assortment”. These findings illuminate empirical evidence indicating that viewable inequality degrades cooperation and they show how a standard feature of evolutionary game models—viz. the aggregation of payoffs during a generation—can double as an information mechanism that facilitates positive assortment.

<p><em>Time is very tight for halting climate change. The COP21 project is not enough, according to the new theory of abrupt climate change. Major meltdowns of ice in Greenland and Antarctica would threaten large coastal cities around the globe, like for instance New York, London and Singapore as well as Shanghai. The discovery of several so-called tipping points substantiates the Hawking warming about irreversibiity.</em><em></em></p>

Abstract Prisoner's Dilemma (PD) games have become a well-established paradigm for studying the mechanisms by which cooperative behavior may evolve in societies consisting of selfish individuals. Recent research has focused on the effect of spatial and connectivity structure in promoting the emergence of cooperation in scenarios where individuals play games with their neighbors, using simple “memoryless” rules to decide their choice of strategy in repeated games. While heterogeneity and structural features such as clustering have been seen to lead to reasonable levels of cooperation in very restricted settings, no conditions on network structure have been established, which robustly ensure the emergence of cooperation in a manner that is not overly sensitive to parameters such as network size, average degree, or the initial proportion of cooperating individuals. Here, we consider a natural random network model, with parameters that allow us to vary the level of “community” structure in the network, as well as the number of high degree hub nodes. We investigate the effect of varying these structural features and show that, for appropriate choices of these parameters, cooperative behavior does now emerge in a truly robust fashion and to a previously unprecedented degree. The implication is that cooperation (as modelled here by PD games) can become the social norm in societal structures divided into smaller communities, and in which hub nodes provide the majority of inter-community connections.

<em>Sincere and profound pessimism about the prospects of implementation success for the COP21 project is warranted. The setting up of the Super Fund is a necessity for avoiding collective choice and decision paradoxes like PD games, sub-optimization and second best solutions. Without massive financial assistance, there will occur widespread reneging on the COP21 objectives (Goal I-III). The system of United Nations Climate Change Conferences, i.e., the yearly conferences held in the framework of the United Nations Framework Convention on Climate Change (UNFCCC), does not offer an organization that is up to the coordination tasks involved in halting climate change. Massive new management is required in each country to fulfill the COP21 objectives.</em>

<p><em>When the COP21 project is analysed with economic and social science models, then one arrives at profound pessimism about the prospects of implementation success. The basic Wildavsky gulf between policy promises and real life implementation outcomes is bound to plague the efforts at coordination to halt the climate change process. The natural sciences have dominated the global warming debate, but it is time to start examining the problematic of delivering great transformation of energy systems to stem the anthropogenic causes of global warming through the emission of greenhouse gases (GHG). The erection of the Super Fund is a necessity for avoiding decision paradoxes like PD games, sub-optimisation and second best solutions. Without massive financial assistance, there will occur widespread reneging on the COP21 objectives (Goal I-III). The system of United Nations Climate Change Conferences, yearly conferences held in the framework of the United Nations Framework Convention on Climate Change (UNFCCC), does not offer an organization that is up to the coordination tasks involved in halting climate change.</em></p>

Cloud computing is based on utility and consumption of computer resources. To solve the security issues in cloud computing, secure computing protocols are often used. Recently, rational parties as a new kind of parties are proposed, who wish to maximize their utilities in secure computing protocols. The utility definitions in most previous rational secure computing protocols derive from prisoner's dilemma game (PD game). In two-party rational computing protocols, parties decide to send their shares according to their utilities. Recently, we revisit the incentives for rational parties in secure computing protocols and give new utility definitions according to them. We find that the new utility definition is not similar to PD game any more. We discuss two-party and multi-party cases, respectively, and prove that parties have incentives to send their share to others. Furthermore, we also prove that parties can maximize their utilities in both cases.

Traditionally, users in clouds are assumed to be willing to store and share files in clouds, where the security and efficiency issues are discussed. However, few studies involve the incentives to share files in clouds. In this paper, we delve into users' incentives for using the cloud system to store and share their files towards the view of game theory. More specifically, the process of file sharing is reduced to an infinitely repeated prisoner's dilemma PD game and the action of sharing files in clouds is considered as the action of cooperation in the infinitely repeated PD game. We incorporate win stay lose shift WSLS strategy into file sharing and simulate it compared with tit-for-tat TFT strategy in clouds. Simulation results show that WSLS is an optimal strategy for users to share their files in clouds. Furthermore, WSLS is robust for unintentional deviation and returns to mutual cooperation after deviation.

In prisoner's dilemma game (shortly, PD game), punishment is most frequently used to promote cooperation. However, outcome varies when different punishment approaches are applied. Here the PD game is studied on a square lattice when different punishment patterns are adopted. As is known to all, tax system, a common tool to adjust the temperature of the economy, is widely used in human society. Inspired by this philosophy, players in this study would pay corresponding taxes in accordance with their payoff level. In this way, public benefit fund is established consequently and it would be utilized to punish defectors. There are two main methods for punishing: slight intensity of punishment (shortly, SLP) and severe intensity of punishment (shortly, SEP). When the totaling of public benefit fund keeps relatively fixed, SLP extends further, which means more defectors would be punished; by contrast, SEP has a smaller coverage. It is of interest to verify whether these two measures can promote cooperation and which one is more efficient. Simulate results reveal that both of them can promote cooperation remarkably. Specifically speaking, SLP shows constant advantage from the point of view either of fractions of cooperation or average payoff.

Indirect reciprocity in three types of social dilemmas

Our study has shown that changes can be induced in human decision-making and emotions by using the PD and PDAS games. This suggests that economic games may provide a way to study cognitive functions in detail by analyzing the structure of the economic games using game theory. In addition, the combined use of economic games and neuroimaging techniques such as fNIRS, fMRI, and MEG may capture and quantify neural the substrates of various cognitive processes in a clinical setting. They might be effective in extracting human emotional ups and downs in the process of the decision-making. Further studies of economic games for patients with mental illness or brain damage are needed to explore this approach further.

We study a system in which N agents have to decide between two strategies θi(i ∈ 1 … N), for defection or cooperation, when interacting with other n agents (either spatial neighbors or randomly chosen ones). After each round, they update their strategy responding nonlinearly to two different information sources: (i) the payoff ai(θi, fi) received from the strategic interaction with their n counterparts, (ii) the fraction fi of cooperators in this interaction. For the latter response, we assume social herding, i.e., agents adopt their strategy based on the frequencies of the different strategies in their neighborhood, without taking into account the consequences of this decision. We note that fi already determines the payoff, so there is no additional information assumed. A parameter ζ defines to what level agents take the two different information sources into account. For the strategic interaction, we assume a Prisoner's Dilemma game, i.e., one in which defection is the evolutionary stable strategy. However, if the additional dimension of social herding is taken into account, we find instead a stable outcome where cooperators are the majority. By means of agent-based computer simulations and analytical investigations, we evaluate the critical conditions for this transition toward cooperation. We find that, in addition to a high degree of social herding, there has to be a nonlinear response to the fraction of cooperators. We argue that the transition to cooperation in our model is based on less information, i.e., on agents which are not informed about the payoff matrix, and therefore rely on just observing the strategy of others, to adopt it. By designing the right mechanisms to respond to this information, the transition to cooperation can be remarkably enhanced. Our results are obtained in an evolutionary PD game with fixed payoffs and a fixed four-player neighborhood, where agents follow a stochastic better response dynamics.

PurposeThe purpose of this paper is to show how CO2 equivalent emissions are closely linked with economic development, over time and also across countries.Design/methodology/approachEmissions data from energy information administration were subjected to macro analysis, regressed upon GDP data, longitudinally and cross‐sectionally.FindingsThe conversion factor linking energy to output to pollution is estimated over time and between economies. It is today far too high, making global climate change almost certain.Practical implicationsGlobal environmental coordination is very difficult to achieve, given the nature of this gigantic PD game in combination with weak institutions for policy making and implementation. The only way to stabilise CO2 emissions is to focus upon the conversion factor linking energy to output to pollution.Originality/valueThe paper shows the clear and Juggernaut type connections between energy‐economic output‐CO2 emissions.

Dilemma game structure hidden in traffic flow at a bottleneck due to a 2 into 1 lane junction