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Understanding the emergence and maintenance of cooperative behaviors represents one of the most interesting challenges in natural and social science. A great number of studies have investigated this question via spatial reciprocity, namely, players are put on networks and obtain their payoffs by playing the game with their neighbors. It has also been verified that in networked population spatial heterogeneity and coevolution setup promote cooperation theoretically and empirically. Inspired by this well-known fact, we consider a coevolution mechanism: players not only adopts the strategy of his opponent, but also learn his opponent's ability. We find a more interesting and counterintuitive phenomenon: compared with the heterogeneity scenario, this coevolution setup does not promote the cooperation in spatial prisoner's dilemma game. With regard to this observation, we unveil that it is related with the range of distribution of individuals' ability. The coevolution setup finally makes the individual's ability shrink towards a single value. To explore the generality of this finding, we have testified on different types of topology structure.

A public database is a special kind of public goods in which data quality control involves solving some basic problems in public management science at the interface with data science. A public database network is a complex body with some physical objects associated with each other (a visible system) and some partners of the public data game (an invisible system); the quality of public data is reflected synthetically by the database technology and evolution of the public data game. From the viewpoint of public goods management, the availability of data in public databases depends on the cooperation evolution of the public data game for same data cleansing technology. The Chinese public data network is regarded as a scale-free complex network on which the corresponding data game is an evolutionary game. Using the models of a prisoners dilemma game and extended prisoners dilemma game, the existence of an evolutionary stable strategy is discussed for the public data game. With the theoretical modeling of complex network analysis, it is further regarded that the collaborators of the public data evolution game would survive on the scale-free complex network, and that cooperative strategy even becomes a stable strategy of the public data evolutionary game through strong punishment or by returning all fines to the punisher. The corruption sub-game model of the public data evolutionary game is established to analyze the influence of the punishers corruption. By constructing the corruption sub-game model, the rights of the data auditor are beneficial for cooperative behavior to survive, and when the stronger rights of the auditor would result in total corruption. Finally, we discuss the extent to which information disclosure and freedom of media help to limit the rights of the public auditor, while helping the cooperator and loyal punisher to irrupt, such that the cooperators survival increases to improve the data quality in public databases.

This paper presents a selective review of decades of empirical research on behavioral games, with a particular focus on experimental games. We suggest that games effectively (but imperfectly) model many human social interactions, and we present important findings from six popular experimental games – Prisoner’s and Social Dilemmas, and the Trust, Ultimatum, Dictator, and Deception games – to discuss their theoretical and empirical implications as well as their various insights into human nature. We close by asking several fundamental questions about games and suggesting several directions and ideas for future research.

In this paper we study a generalized variation of the replicator dynamic that involves several species and sub-species that may interact. We show how this dynamic comes about from a specific finite-population model, but also show that one must take into consideration the dynamic nature of the population sizes (and hence proportions) in order to make the model complete. We provide expressions for these population dynamics to produce a kind of multi-replicator dynamic. We then use this replicator dynamic to show that cooperation can emerge as a stable behavior when two species each play prisoner’s dilemma as their intra-species game and a form of zero-sum predator prey game as their inter-species game. General necessary and sufficient conditions for cooperation to emerge as stable are provided for a number of game classes. We also showed an example using Hawk–Dove where both species can converge to stable (asymmetric) mixed strategies.

The preferential reference selection is a new research direction in the evolutionary game theory which provides a paradigmatic framework to study the evolution of cooperation. This paper presents a new reference selection model called self-adaptive win-stay-lose-shift (WSLS) mechanism for strategy updating. Within the proposed reference selection mechanism, the reference model is determined by a self-adaptive way that each individual retains its reference if the receiving payoff does not decline, otherwise switches the reference by randomly selecting a new one from its remaining neighbors. Two social dilemma models, the prisoner's dilemma game (PDG) and public good game (PGG), are utilized to simulate the interactions among individuals and verify the effectiveness of the presented mechanism on square lattices. The simulation results demonstrate that this simple mechanism can evidently increase the cooperation level, which reveals a new means to promote the emergence of cooperation.

A linear public good experiment adopted from Holt and Laury [1997. Classroom games: Voluntary provision of a public good. Journal of Economic Perspectives, 11(4), 209–215.] has been employed to investigate strategic behaviour in pollution abatement among African climate decision-makers. The experiment consisted of three groups, of which groups 2 and 3 received one and two treatments, respectively. The first treatment entailed publicly disclosing the pollution of each member of a group by placing a corresponding colour-coded card in front of each subject, while the second involved the withdrawal of the public disclosure. Group 2 received the first treatment; Group 3 received both the first and second treatments in succession. We found that the untreated group (baseline) polluted more than the two treated groups, and there was no statistically significant difference between the pollution abatement of the two treated groups. These results suggest that public disclosure potentially drives pollution abatement ...

How to exploit public non-renewable resources is a public goods dilemma. Individuals can choose to limit the depletion in order to use the resource for a longer time or consume more goods to benefit themselves. When the resource is used up, there is no benefit for the future generations any more, thus the evolutionary process ends. Here we investigate what mechanisms can extend the use of resources in the framework of evolutionary game theory under two updating rules based on imitation and aspiration, respectively. Compared with imitation process, aspiration dynamics may prolong the sustainable time of a public resource.

Patience—low delay discounting—has been shown to predict cooperative behavior in environments where cooperation conflicts with competitive aspirations. Indeed, impatience seems to be associated to a greater concern for the latter (i.e., for the individual’s relative standing). But what about intergroup-competition situations, where competitive sentiments against outgroups can trigger ingroup cooperation? We analyze the connection between delay discounting and performance in two problem-solving tasks with either individual or intergroup-competition incentives. We find a positive relationship between the mean patience of the members of a group (both when using long-term discounting and short-term discounting, also known as present bias) and the within-group cooperative synergy during intergroup competition. Further exploratory analyses based on a follow-up social preferences task suggest that, for long-term discounting, this result may be explained by patient (vs. impatient) individuals’ propensity to be initially cooperative and to subsequently treat group members based on reciprocal fairness instead of strict equality. For short-term discounting, or present bias, our exploratory analyses do not yield any significant result, meaning that we are unable to provide a social-preferences-based explanation to the higher synergy observed in groups with less present biased individuals.

Culture is a central concept broadly studied in social anthropology and sociology. It has been gaining increasing attention in economics, appearing in research on labor market discrimination, identity, gender, and social preferences. Most experimental economics research on culture studies cross-national or cross-ethnic differences in economic behavior. In contrast, we explain laboratory behavior using two cultural dimensions adopted from a prominent general cultural framework in contemporary social anthropology: group commitment and grid control. Groupness measures the extent to which individual identity is incorporated into group or collective identity; gridness measures the extent to which social and political prescriptions intrinsically influence individual behavior. Grid-group characteristics are measured for each individual using selected items from the World Values Survey. We hypothesize that these attributes allow us to systematically predict behavior in a way that discriminates among multiple forms of social preferences using a simple, parsimonious deductive model. The theoretical predictions are further tested in the economics laboratory by applying them to the dictator, ultimatum, and trust games. We find that these predictions are confirmed overall for most experimental games, although the strength of empirical support varies across games. We conclude that grid-group cultural theory is a viable predictor of people’s economic behavior, then discuss potential limitations of the current approach and ways to improve it.

The prisoner's dilemma game is a simple model to understand the evolution of cooperation in complex systems. In this work, we introduce the element of noise to the payoffs of the spatial prisoner's dilemma game and study its effects on the evolution of cooperations. A tunable parameter, termed as the noise strength (α), is introduced into the model to mimic the effects of noise in the individual fitness calculation. Our modified model remarkably promotes the behavior of cooperation, which may help us to better understand the emergence of cooperation in natural, social and economical systems.

Both in the field and in the lab, participants frequently cooperate, despite the fact that the situation can be modelled as a simultaneous, symmetric prisoner’s dilemma. This experiment manipulates the payoff in case both players defect, and explains the degree of cooperation by a combination of five motives: the size of gains from cooperation, expectations about cooperativeness in the population in question, the degree of risk and loss aversion, and the degree by which a participant is averse to inequity. Information about these motivational forces stems from additional within subjects tests. All five factors are significant only if one controls for all the other motives, which suggests that a prisoner’s dilemma is a game jointly characterised by these five motives. The need to control for the remaining explanations seems to be the reason why earlier attempts at explaining choices in the prisoner’s dilemma with personality have not been successful.

This study explores the impact of government intervention on the evolution of cooperation using a popular framework for understanding cooperative behavior (the public goods game). Agents either contribute to the production of a shared public good or free-ride on the efforts of others. This game traditionally results in mass free-riding (a sub-optimal outcome), in which case a government can intercede by levying taxes and providing the public good to increase welfare. Is this still the case when looking at an evolutionary framework with natural selection? Theoretical results suggest that the government “levels the playing field”, allowing cooperative and uncooperative behavior to coexist longer than it ordinarily would, but it cannot change the course of evolution.

Reciprocity is an important factor in human-human interaction, so it can be expected that it should also play a major role in human-robot interaction (HRI). Participants in our study played the Repeated Prisoner's Dilemma Game (RPDG) and the mini Ultimatum Game (mUG) with robot and human agents, with the agents using either Tit for Tat (TfT) or Random strategies. As part of the study we also measured the perceived personality traits in the agents using the TIPI test after every round of RPDG and mUG. The results show that the participants collaborated more with humans than with a robot, however they tended to be equally reciprocal with both agents. The experiment also showed the TfT strategy as the most profitable strategy; affecting collaboration, reciprocation, profit and joint profit in the game. Most of the participants tended to be fairer with the human agent in mUG. Furthermore, robots were perceived as less open and agreeable than humans. Consciousness, extroversion and emotional stability were perceived roughly the same in humans and robots. TfT strategy became associated with an extroverted and agreeable personality in the agents. We could observe that the norm of reciprocity applied in HRI has potential implications for robot design.

We provide an experimental investigation of the fair rule preference and its effect on anonymous cooperation, intending to test the hypothesis that people who exhibit high degrees of rule inequality aversion—consider “equality and mutual obligation under the social contract” as justified, are disgusted with free-rider behavior in the public goods game and are more likely to be conditional cooperators and make conditional contributions. Based on experimental work related to rule-preferences Chlas and Moffatt (Giving in dictator games: experimenter demand effect or preference over the rules of the game? (No. 2012, 044). Jena Economic Research Papers, 2012) and the public goods game Fischbacher et al. (Am Econ Rev 100(1):541–556, 2010), we designed a dictator game with the option of buying a veto (when the veto was purchased, the level of rule inequality decreased, making it an ultimatum game) to measure rule preference, i.e., rule inequality aversion, and conducted a two-stage public goods experiment to identify the cooperation preferences and repeated cooperation levels of participants. We investigated the relationship between rule preferences and cooperative preferences (conditional reciprocal preference) and tried to explain the adjustments people made when making repeated contributions of public goods (conditional cooperation behavior) from a rule preference perspective. The results show that: (1) Heterogeneous rule-inequality-aversion preferences are found in lab; (2) The stronger the rule-inequality-aversion preference is, the higher the probability is for the individual to become a conditional cooperator in public goods experiment; (3) Individuals who have stronger rule-inequality-aversion are more sensitive to the contributions that are deviated from the norm. Compared to the theory of conditional cooperation types, rule-inequality-aversion preference has a better explanation power when it comes to the behavior adjustment in repeated public goods contribution.

We built a new indirect reciprocity model based on binary image scores, where an agent’s strategy and norm co-evolve. The norm, meaning what behavior is evaluated as “good” or “bad,” stipulates how image scores of two agents playing a game is altered, which has been presumed to be a fixed value in most previous studies. Also, unlike former studies, our model allows an agent to play with an agent who has a different norm. This point of relaxing the freedom of the model pulls down cooperation level vis-a-vis the case where an agent always plays with another one having same norm. However, it is observed that a rather larger dilemma shows robust cooperation establishing compared with a smaller dilemma, since a norm that punishes a so-called second-order free-rider is prompted. To encourage the evolution of norms to be able to punish second-order free-riders, a society needs a small number of defectors. This is elucidated by the fact that cases with action error are more cooperative than those without action error.

Boycotts are among the most frequent forms of consumer expression against unethical or egregious acts by firms. Most current research explains consumers’ decisions to participate in a boycott using a universal cost-benefit model that mixes instrumental and expressive motives. To date, no conceptual framework accounts for the distinct behavioral motives for boycotting though. This article focuses on motivational heterogeneity among consumers. By distinguishing two stable behavioral models—a self-regarding type and a strongly reciprocal type—we introduce the notion of strong reciprocity to the boycott literature. We argue that the presence of strongly reciprocal consumers can enhance boycott success. First, in interactions with the target firm, strongly reciprocal consumers perceive higher levels of egregiousness and are more willing to engage in boycotting behavior, even in unfavorable strategic conditions, which provides a stable basis for boycotting. Second, in interactions with self-regarding consumers, strongly reciprocal consumers are willing to sanction those others, according to whether they participate in the boycott, which increases overall participation in and the likelihood of success of a consumer boycott. These findings have implications for further research, as well as for firms, nongovernmental organizations, and boycotters.

The progress of Islamic microfinance is very slow despite the fact that mainstream Islamic finance has been growing marvellously. This paper explains the logic of underdeveloped Islamic microfinance, placing an emphasis on the supply side of funds. It argues that Islamic altruism appears to be dependent on reciprocity backed by mutual belief in the omnipotence and omniscience of the absolute power. Strong reciprocity however, may create a ‘dilemma’ - to be or not to be unconditional altruist - on the actors which might ironically drain the supply of funding to the poor. Evidence to support this hypothesis has been provided explaining some cases and other anecdotal facts. The research proposes that besides relying on actors’ belief towards omnipotence and omniscience, appropriate safeguards against potential violation of cooperative and other Islamic social norms should be devised ex ante; otherwise Islamic microfinance is unlikely to thrive in the future.

The most perplexing experimental results on fairness come from the dictator game where one of two players, the dictator, decides how to divide a resource with an anonymous player. The dictator, acting self-interestedly, should offer nothing to the anonymous second player, but in experimental studies, dictators offer much more than nothing. We developed a multilevel selection model to explain why people offer more than nothing in the dictator game. We show that fairness can evolve when population structure emerges from the aggregation and limited dispersal of offspring. We begin with an analytical model that shows how fair behavior can benefit groups by minimizing within-group variance in resources and thereby increasing group fitness. To investigate the generality of this result, we developed an agent-based model with agents that have no information about other agents. We allowed agents to aggregate into groups and evolve different levels of fairness by playing the dictator game for resources to reproduce. This allowed multilevel selection to emerge from the spatiotemporal properties of individual agents. We found that the population structure that emerged under low population densities was most conducive to the evolution of fairness, which is consistent with group selection as a major evolutionary force. We also found that fairness only evolves if resources are not too scarce relative to the lifespan of agents. We conclude that the evolution of fairness could evolve under multilevel selection. Thus, our model provides a novel explanation for the results of dictator game experiments, in which participants often fairly split a resource rather than keeping it all for themselves.

This paper presents a novel generalised indirect reciprocity approach for promoting cooperation in social dilemma games. Here, players decide upon an action to play in the game based on public information or “external cues” rather than individual-specific information. The public information is constantly updated according to the underlying learning model. Comprehensive simulation experiments using the N-player Prisoner's Dilemma PD and Snowdrift SD games show that generalised indirect reciprocity promotes high levels of cooperation across a wide range of conditions. This is despite the fact that the make-up of player groups is continually changing. As expected, the extent of cooperative behaviour observed in the “constraint-relaxed” N-player SD game is significantly higher than the N-player PD game. Our proposed generalised indirect reciprocity model may shed light on the conundrum of cooperation between anonymous individuals.

Monopolists set prices and if the good is unessential this may place the consumer in an uncomfortable position. But if the good is essential the consumer faces a pay-to-live or -die choice. Dictator and ultimatum games are superficially similar in that one game offers the right of refusal, while the other does not. The dictator monopoly is, however, not a game, and behaviour could be radically different in the market environment versus game environment. We recast the dictator game as a dictator monopoly experiment and find that the fairness characteristic of the game evaporates quickly as rounds progress.

Classical economic theory assumes that people are rational and selfish, but behavioral experiments often point to inconsistent behavior, typically attributed to “other regarding preferences.” The Ultimatum Game, used to study fairness, and the Trust Game, used to study trust and trustworthiness, have been two of the most influential and well-studied examples of inconsistent behavior. Recently, evolutionary biologists have attempted to explain the evolution of such preferences using evolutionary game theoretic models. While deterministic evolutionary game theoretic models agree with the classical economics predictions, recent stochastic approaches that include uncertainty and the possibility of mistakes have been successful in accounting for both the evolution of fairness and the evolution of trust. Here I explore the role of population structure by generalizing and expanding these existing results to the case of non-random interactions. This is a natural extension since such interactions do not occur randomly in the daily lives of individuals. I find that, in the limit of weak selection, population structure increases the space of fair strategies that are selected for but it has little-to-no effect on the optimum strategy played in the Ultimatum Game. In the Trust Game, in the limit of weak selection, I find that some amount of trust and trustworthiness can evolve even in a well-mixed population, however, the optimal strategy, although trusting if the return on investment is sufficiently high, is never trustworthy. Population structure biases selection towards strategies that are both trusting and trustworthy trustworthy and reduces the critical return threshold, but, much like in the case of fairness, it does not affect the winning strategy. Further considering the effects of reputation and structure, I find that they act synergistically to promote the evolution of trustworthiness.

It has been suggested that economics could benefit greatly from recent developments in evolutionary game theory. In fact, key authors in the study of the role of ethical norms in economic behavior like Amartya Sen argue that evolutionary game theory could contribute much to the study of social norms and behavior. Others have suggested that evolutionary game theory could be most helpful for formalizing the work of classic authors in evolutionary and institutional economics like Thorstein Veblen. Here I discuss the behavioral assumptions of evolutionary game theory models, and Jorgen Weibull's approach in particular. I will argue that Weibull's models, and evolutionary game theory in general, pose overly strong restrictions on the explanation of human behavior, which limit the potential of evolutionary explanation. I also suggest Tony Lawson's population-variety-reproduction-selection (PVRS) model as an alternative evolutionary framework that can successfully accommodate developments in behavioral economics, while also providing a solution to important critiques of Darwinian evolutionary analysis made by Richard Nelson, among others.

The dominant understanding of how motivations to contribute to public goods are generated and sustained is largely shaped by the combined action of rational choice theory and neoclassical economics. This understanding relies on three key assumptions: individualism, instrumentalism and market equilibration. This paper questions the theoretical consistency and empirical relevance of these assumptions and of their associated policy model. I argue that a significant revision of this motivational theory is needed, one that takes into account intrinsic incentives, trust and strong reciprocity, as well as the effect of social and institutional context, monetization and market interactions on the propensity to contribute to public goods. The paper concludes by outlining the implications of this theoretical reconsideration for the organization of scientific research and for more effective policy-making to sustain public goods provision. Copyright © 2015 John Wiley & Sons, Ltd and ERP Environment

Network reciprocity is discussed in terms of initial cooperation fraction.Simulation reveals the influence from initial condition is significant.The influence is explained from the concept END and EXP the author presented previously. Although the initial cooperation fraction and its arrangement obviously impacts the equilibrium in spatial prisoner's dilemma (SPD) games, most of the previous studies relying on a simulation approach have by conformity assumed a value of 0.5, thus implying an equal distribution of cooperators and defectors as the established premise. This study first points out that depending on target applications, i.e., biological or general evolutionary dynamical systems, we must select the initial cooperation fraction and its spatial distribution carefully to avoid a misleading conclusion. On the basis of comprehensive numerical experiments and a deductive discussion, wherein both the rule of strategy update and the underlying network are varied, we present a panoramic view of the effects of initial cooperation settings on evolutionary dynamics. Several non-trivial findings are revealed concerning the different impacts of deterministic or stochastic updating, or of homogeneous or heterogeneous underlying topology on evolutionary dynamics.

Spontaneous turn taking phenomenon can be observed in many self-organized systems, and the mechanism is unclear. This paper tries to model it by evolutionary dilemma games with memory mechanism. Prisoner's dilemma, Snowdrift (including Leader and Hero) and Stag-hunt games are unified on an extended S-T plane. Agents play game with all the others and make decision by the last game histories. The experiments find that when agents remember last 2-step histories or more, a kind of cooperative turn taking (CAD) bursts at the area of Snowdrift game with restriction of S + T > 2R and S ≠ T, while the consistent strategy (DorC) gathers on the line of S + T > 2R and S = T. We also find that the system's fitness ratio greatly improved with 2-step memory.

The existence of cooperation in the social dilemma has been extensively studied based on spatial structure populations, namely, the so-called spatial reciprocity. However, vast majority of existing works just simply presume that agents can offer the discrete choice: either the cooperative (C) or defective (D) strategy, which, to some extent, seems unrealistic in the empirical observations since actual options might be continuous, mixed rather than discrete. Here, we propose discrete, continuous and mixed strategy setups in the social dilemma games and further explore their performance on network populations. Interestingly, it is unveiled that there is actually considerable inconsistency in terms of equilibrium among different strategy games. Furthermore, we reveal how different cooperative arrangements among these three strategy setups can be established, depending on whether the presumed dilemma subclass is a boundary game between prisoner's dilemma game and Chicken game or between prisoner's dilemma game and Stag-Hunt game.

We consider a public goods game which incorporates guilt-aversion/surprise-seeking and the attribution of intentions behind these emotions (Battigalli and Dufwenberg, 2007; Khalmetski et al., 2015). We implement the induced beliefs method (Ellingsen et al., 2010) and a within-subjects design using the strategy method. Previous studies mainly use dictator games - whose results may not be robust to adding strategic components. We find that guilt-aversion is far more important than surprise-seeking; and that the attribution of intentions behind guilt-aversion/surprise-seeking is important. Our between-subjects analysis confirms the results of the within-subjects design.

Indirect reciprocity is a mechanism for the evolution of cooperation that is relevant for prosocial behavior among humans. Indirect reciprocity means that my behavior towards you also depends on what you have done to others. Indirect reciprocity is associated with the evolution of social intelligence and human language. Most approaches to indirect reciprocity assume obligatory interactions, but here we explore optional interactions. In any one round a game between two players is offered. A cooperator accepts a game unless the reputation of the other player indicates a defector. For a game to take place, both players must accept. In a game between a cooperator and a defector, the reputation of the defector is revealed to all players with probability Q. After a sufficiently large number of rounds the identity of all defectors is known and cooperators are no longer exploited. The crucial condition for evolution of cooperation can be written as hQB>1, where h is the average number of rounds per person and B=(b/c)-1 specifies the benefit-to-cost ratio. We analyze both stochastic and deterministic evolutionary game dynamics. We study two extensions that deal with uncertainty: hesitation and malicious gossip.

The evolution of cooperation among intelligent agents is a fundamental issue in multi-agent systems. It is well accepted that the individual strategy-updating rules play a significant role in the cooperation dynamics on graphs. The imitation mechanisms account for a large proportion of these rules, in which an individual will choose a neighbor with higher payoff and follows its strategy. In this paper, we propose a strategy-updating rule based on incremental learning process for continuous prisoner’s dilemma game. Under our strategy-updating rule, each individual refreshes its decision according to original strategy (self-opinion) and new strategy learnt from one of neighbors (social-opinion). The simulation results show the incremental learning rule can enhance cooperation dramatically when individual has higher resistance to imitate others or lower payoff sensitivity. We also find that the incremental learning rule has greater influence when individual obtains fewer information of neighbors’ payoff. The reason behind the phenomena is also given. Our results may shed some light on how cooperative strategies are actually adopted and spread in spatial network.

The standard theories of cooperation in humans, which depend on repeated interaction and reputation effects among self-regarding agents, are inadequate. Strong reciprocity, a predisposition to participate in costly cooperation and the punishment, fosters cooperation where self-regarding behaviors fail. The effectiveness of socially coordinated punishment depends on individual motivations to participate, which are based on strong reciprocity motives. The relative infrequency of high-cost punishment is a result of the ubiquity of strong reciprocity, not its absence.

The communication of participants to identify an acceptable bargaining outcome in the Nash bargaining game is all about fairness norms. Participants introduce fairness norms which yield a better outcome for themselves in order to convince the other participant of their bargaining proposal. Typically, these fairness norms are in line with theoretical predictions, which support a wide variety of different but fair outcomes the participants can choose from. In this experiment, we play two treatments of the Nash bargaining game: in one treatment, the participants play a dictator game prior to bargaining, and in the other treatment they do not. We find that participants who have not played the dictator game intensively discuss the outcome of the game and come to solutions closer to the equal split of the pie the longer they chat. This effect vanishes as soon as the participants have previous experience from a dictator game: instead of chatting, they establish the fairness norm introduced in the dictator game. Remarkably, if the dictator is unfair in the dictator game, he also gets a higher share of the pie in the Nash bargaining game.

The N-Person Iterated Prisoner's Dilemma (NIPD) is an interesting game that has proved to be very useful to explore the emergence of cooperation in multi-player scenarios. Within this game, the way that agents are interconnected is a key element that influences cooperation. In this context, complex networks provide a realistic model of the topological features found in Nature and in many social and technological networks. Considering these networks, it is interesting to study the network evolution, given the possibility that agents can change their neighbors (dynamic rewire), when non-cooperative behaviors are detected. In this paper, we present a model of the NIPD game where a population of genetically-coded agents compete altogether. We analyze how different game parameters, and the network topology, affect the emergence of cooperation in static complex networks. Based on that, we present the main contribution of the paper that concerns the influence of dynamic rewiring in the emergence of cooperation over the NIPD.

Variation in learning rates within populations suggests that evolutionary game theory may not necessarily be restricted to uniform time scales associated with the game interaction and strategy adaption evolution. Using agent-based evolutionary simulation in the framework of prisoner's dilemma game, we demonstrate the sustainability of cooperation and the emergence of different macro-effects, when equipping agents with non-uniform time scale preferences. We employ a spatial random regular grid to describe the social interactions among agents. We conclude that the cooperation level has a strong dependence on the population composition, and the suitable fraction of the fast-updating players in the system which is associated with the maximal cooperation frequency has been found out. Besides, the extent of the promotive effect of diversifying time scales is also closely related with the payoff adoption rules in strategy updating, especially when we invent a past history for each agent. Summing up the gained results, a general conclusion can be drawn, saying that the combination of these factors (e.g. time scales and memory) gives rise to rich dynamic behavior of the system.

One of the triumphs of evolutionary biology is the discovery of robust mechanisms that promote the evolution of cooperative behaviors even when those behaviors reduce the fertility or survival of cooperators. Though these mechanisms, kin selection, reciprocity, and nonlinear payoffs to cooperation, have been extensively studied separately, investigating their joint effect on the evolution of cooperation has been more difficult. Moreover, how these mechanisms shape variation in cooperation is not well known. Such variation is crucial for understanding the evolution of behavioral syndromes and animal personality. Here, I use the tools of kin selection theory and evolutionary game theory to build a framework that integrates these mechanisms for pairwise social interactions. Using relatedness as a measure of the strength of kin selection, responsiveness as a measure of reciprocity, and synergy as a measure of payoff nonlinearity, I show how different combinations of these three parameters produce directional selection for or against cooperation or variation in levels of cooperation via balancing or diversifying selection. Moreover, each of these outcomes maps uniquely to one of four classic games from evolutionary game theory, which means that modulating relatedness, responsiveness, and synergy effectively transforms the payoff matrix from one the evolutionary game to another. Assuming that cooperation exacts a fertility cost on cooperators and provides a fertility benefit to social partners, a prisoner’s dilemma game and directional selection against cooperation occur when relatedness and responsiveness are low and synergy is not too positive. Enough positive synergy in these conditions generates a stag-hunt game and diversifying selection. High levels of relatedness or responsiveness turn cooperation from a fitness cost into a fitness benefit, which produces a mutualism game and directional selection for cooperation when synergy is not too negative. Sufficiently negative synergy in this case creates a hawk-dove game and balancing selection for cooperation. I extend the results with relatedness and synergy to larger social groups and show that how group size changes the effect of relatedness and synergy on selection for cooperation depends on how the per capita benefit of cooperation changes with group size. Together, these results provide a general framework with which to generate comparative predictions that can be tested using quantitative genetic techniques and experimental techniques that manipulate investment in cooperation. These predictions will help us understand both interspecific variation in cooperation as well as within-population and within-group variation in cooperation related to behavioral syndromes.

The nursing of non-offspring is referred to as allonursing. Reciprocity is a hypothesized cause of allonursing, but previous studies have not strongly supported or found no evidence in support for this hypothesis. Biological market theory was applied to 25 reindeer (Rangifer tarandus) does and their calves to investigate allonursing reciprocity across bouts and within dyads and assess the diversity of allonursing partners. We also investigated whether variation in allonursing would be associated to relatedness within dyads. We recorded both the occurrence and the duration of 1027 successful allonursing solicitations. All does allonursed, and only three of the 25 calves were not observed being allonursed. Throughout the study, 234 allonursing dyadic pairs were observed. Does allonursed the calves of several does, but allonursing was not distributed evenly among all potential partners. Twenty does were members of at least 1 dyad with a high degree of reciprocity based on the number of allonursing bouts exchanged within the dyad. We found evidence of both relative and absolute allonursing reciprocity at the group level. Across bouts and within dyads, the reciprocal allonursing indexes varied greatly both for frequency and for duration, with an average tendency towards unidirectionality. Evidence of strong reciprocity within dyads was found in 32 dyads for number of allonursing bouts and in 25 dyads for duration of allonursing bouts. Across bouts and within dyads, the number of allonursing bouts received was not influenced by relatedness, allonursing bouts given or absolute rank difference. Allonursing was not interchanged for rank-related benefits. Our results provide evidence of reciprocal allonursing at the group level, across bouts and within dyads, and reciprocal allonursing among chosen partners. Our results point to the usefulness of applying the biological market theory to allonursing and of considering allonursing as a tradable commodity, traded for itself, among chosen partners.

We successfully replicated Dana, Cain, and Dawes’ study (2006) using a dictator game with an exit option with a Japanese sample. The exit option allowed the dictator to leave the recipient with nothing by paying a small fee, while also ensuring that the recipient never noticed that the dictator game was being played. If the dictator was motivated by fairness, or even self-interest, there would be no reason to choose the exit option. However, our study, as well as the original study, demonstrated that approximately 40% of participants chose the exit option. Based on these results, we argue that the altruistic behavior exhibited during the standard dictator game represents a default strategy for reputation management.

Available online 28 July 2014. When we become aware that our past actions carry information about qualities that we possess or lack, which others use to decide how to deal with us, are we unconcerned, content to rely on what we have done, or do we take action to alter this information? We study this question experimentally using generosity as a sign and a signal of trustworthiness, and a trust game. Subjects play a dictator game unaware that later they will play a trust game and that their level of generosity in the dictator game will be revealed to trusters, with some inaccuracy, before trusters decide whether to trust or not. Once made aware of what follows, trustees have the option to play a second dictator game, from which their choice will be accurately conveyed to trusters in addition to their decision in the initial game. Consistent with ‘countersignalling theory’, those who, in the first dictator game, were either miserly or generous do not play the second dictator game, resigned or content with the information conveyed by their past actions. Those neither miserly nor generous in the first dictator game, an intermediate generous group, are likeliest to use the second dictator game; many of them for the purpose of signalling, so that they are not confused with the miserly.

The origin of evolutionary cooperation among individuals remains an unsolved issue across several disciplines; especially, the relation between the population structure and the emergence of cooperation is the key of the issue. Community structure is ubiquitous in social and biological networks. It is not clear until now whether the community structure promotes or inhibits cooperation. By defining the common neighbor coefficient of a network, the iteration dynamics of the prisoner’s dilemma game indicates that smaller value of the common neighbor coefficient of a network promotes cooperation in statistical significance for the prisoner’s dilemma game. Analyses show that the community networks usually have larger value of common neighbor coefficient than the ER random networks with the same number of nodes and edges, which shows that the community structure usually inhibits cooperation in the spatial prisoner’s dilemma game.

Mind a valos eletbeli szituaciokban, mind kiserleti jatekhelyzetekben hatekonyan mozditja elő a kooperaciot az un. erős negativ reciprocitas vagy altruista buntetes, ahol is a szemely sajat koltsegere is szankciokat ro a normaszegőkre. Ugyanakkor valoszinű, hogy a szocialis kontextus es a resztvevők szemelyisegenek fuggvenyeben a buntetes alternativ szerepekre tehet szert. A buntető viselkedes megjeleneset vizsgaltuk 80 fő reszvetelevel, erősen versengő jellegű Kozjavak jatek keretein belul. A kozjohoz valo hozzajarulasok merteke a jatek alatt a buntetesi lehetőseg ellenere folyamatosan csokkent. A hozzajarulasok merteke nem gyakorolt szignifikans hatast sem a kapott, sem pedig a kiosztott buntetesekre. Az eredmenyek arra utalnak, hogy bizonyos szocialis kontextusok (jelen esetben az intenziv versenges) modosito hatassal lehetnek a buntetes altal jatszott szerepre. A resztvevők a magasabb helyezes es az anyagilag eredmenyesebb vegkifejlet elerese erdekeben buntettek egymast. A buntetes ahelyett, hogy az e...

How to interpret the emergence and ubiquity of cooperation between selfish agents has become a long-standing puzzle among the scientific communities. In this paper, we propose a co-evolutionary prisoner’s dilemma model to illustrate the evolution of cooperation, in which the model evolution can be divided into two basic steps: (i) strategy update: all agents play the game and perform the strategy update according to the Fermi rule; (ii) topology adjustment: each agent can have a chance to prune the connection with a defecting neighbor so as to decrease the potential benefit loss via an adjustment parameter ( α ). Large quantities of numerical simulations indicate that the cooperation level in the stationary state will be highly elevated, when compared to the traditional prisoner’s dilemma game on regular lattices. Meanwhile, we have also observed that the degree distribution of network will be broadened or more skewed and structural heterogeneities will also become higher when the dynamical adjustment of interaction topology is allowed during the system evolution. In addition, it is also proven that the tunable parameter α controls the link reconnection process, and even the node elimination and reproduction so that the whole cooperation level can be greatly influenced. Thus, the study points out a suitable way for the sustainability of cooperation in structured populations, and current findings are conducive to further understand the collective cooperation phenomenon within many biological, social, economic and even man-made systems.

In the context of an indefinitely repeated veto game, we devise an experiment to distinguish between alternative explanations of generous behavior (accepting negative payoffs): altruism, intrinsic backward-looking reciprocity, and instrumental forward-looking reciprocity. Our results are broadly consistent with the hypothesis that observed sacrifices are motivated by equilibrium selfish, forward-looking reciprocal behavior although we find a more subtle way in which past kindness affects behavior.

We study pure indirect reciprocity by setting up a modified dictator game with three players A, B, and C acting sequentially. Subject A takes a share of a pie and passes the rest to subject B, while B divides the rest between herself and C. We find that this consecutive three-person dictator game increases generosity compared with the traditional two-person dictator game. We analyze the influence of social interaction and uncertainty. In treatments with certainty we observe pure indirect reciprocity: B indirectly reciprocates for A’s behavior in the decision on how generous to be to C.

In this study, we test experimentally how a player who must decide how much money to transfer back in a trust game is affected by the experiment’s monetary incentive. We find that positive reciprocity or altruism in a trust game is affected by the player’s attachment to the money he received. We also argue that in a trust game played with virtual money, the players are affected by their willingness to punish the other player, consistent with the ‘altruistic punishment’ hypothesis.

We studied a public good game, in which metanorms work, permitted new entries. Although whoever wants to entry the game, either cooperators or noncooperators, can try to participate in the game, a manager of the game can control a policy to permit who are ok. By changing the level of control, we investigated what type of policies is effective to maintain cooperation. Especially, we compared a strict policy of population management that only cooperative participants are permitted to entry it, and a simple policy of population management that non-cooperative participants are permitted. According to our simulation of the model, it is revealed surprisingly that a level of cooperation of the game collapses when a strict policy was adopted. On the other hand, cooperation level maintains high robustly if a tolerant policy that some invaders who are perfect defectors are permitted. We conclude that an existence of a few amount of defection has an effect on cooperation of the society. We call this effect a social vaccine effect.

This experimental investigation explores differences in reciprocal norms between friends and strangers and the effects of culture on reciprocity. Based on altruistic and strong reciprocity theories, a hybrid trust-dictator game tested the influence of relationship (i.e. friends vs. strangers), treatment (i.e. positive vs. negative) and culture (i.e. collectivistic vs. individualistic) on reciprocation. The results show that participants reciprocated more positively when treated positively in general. However, the results demonstrate intercultural differences in reciprocal norms, specifically in the negative treatment condition. Participants from the individualistic culture provided stronger punishment to the norm violator, compared to participants from the collectivistic culture. We discuss implications of the impact of relationship and culture on reciprocation with respect to the olive branch response.

Group interactions on structured populations can be represented by the public goods game on networks. During the evolutionary games, selective investment mechanism fosters social cooperative behavior. First we focus on star-like graphs to provide some light on why selective investment mechanism can promote collective cooperation. Then we implement public goods game with this mechanism on scale free networks to investigate behavior properties of individuals within different social environments. We indicate that high-degree nodes are predominantly inert owning largely to their satisfaction with their status, while low-degree nodes are very active due to their strive towards higher prosperity. Besides, we introduce the Gini coefficient to describe social inequality and find that large multiply factor r favors social fairness. Our work is applicable for community supervision and social wealth regulation.