Evolution of conditional cooperation in public good games (original) (raw)
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Rewards and the evolution of cooperation in public good games
Biology Letters, 2014
Properly coordinating cooperation is relevant for resolving public good problems, such as clean energy and environmental protection. However, little is known about how individuals can coordinate themselves for a certain level of cooperation in large populations of strangers. In a typical situation, a consensus-building process rarely succeeds, owing to a lack of face and standing. The evolution of cooperation in this type of situation is studied here using threshold public good games, in which cooperation prevails when it is initially sufficient, or otherwise it perishes. While punishment is a powerful tool for shaping human behaviours, institutional punishment is often too costly to start with only a few contributors, which is another coordination problem. Here, we show that whatever the initial conditions, reward funds based on voluntary contribution can evolve. The voluntary reward paves the way for effectively overcoming the coordination problem and efficiently transforms freelo...
Journal of Economic Psychology, 2009
In the recent literature, several hypotheses have been put forward in order to explain the decline of contributions in repeated public good games. We present results of an experiment which allows to evaluate these hypotheses. The main characteristics of our experimental design are a variation of information feedback and an elicitation of individual beliefs about others' contributions. Altogether, our data support the hypothesis of conditional cooperation with a selfish bias.
Public Good Contributions, Signalling, and the Evolution of Trust
This paper develops a theory of the evolution of preferences for honesty, trust, and the voluntary provision of public goods in a society composed exclusively of rational, Bayesian optimisers. Unlike conventional evolutionary models, player types are not deÞned by their strategies, but rather (as in standard economic theory) by their preferences. Thus agents do not play Þxed, 'wired-in' strategies, but rather choose strategies that maximise their expected utilities. In each stage of his or her 'career', an agent decides (a) whether to honour trust in a bilateral market transaction, and (b) whether to contribute to the provision of a non-excludable public good. We study the evolution of a community consisting of 'opportunists', who simply maximise material payoffs, and 'honest types', who prefer to honour trust and contribute to the provision of public goods. While individual interactions are one-shot, agents know the history of play of all others in t...
Humans prefer to copy success rather than the social norm in a cooperative game
2021
It is often claimed that human cooperation is special, and can only be explained by geneculture co-evolution favouring a desire to follow pro-social norms. If this is true then individuals should be motivated to both observe, and copy, common social behaviours (social norms). Previous economic experiments, using the public goods game, have suggested individuals are motivated to follow social norms. However, natural selection should favour individuals whom prefer to discover and copy successful behaviours, and previous experiments have often not shown examples of success. Here we test, on 489 participants, if individuals are more motivated to learn about, and more likely to copy, either common or successful behaviours. Using the same cooperative game and instructions, we find that individuals are primarily motivated to copy successful rather than common behaviours. Consequently, social learning disfavours costly cooperation, even when individuals can observe a stable, pro-social, norm. Our results suggest that human social learning mechanisms have evolved to maximize personal success, and call into question explanations for human cooperation based on cultural evolution and/or a desire to follow social norms.
Rewarding cooperation in social dilemmas
2007
One of the most direct human mechanisms of promoting cooperation is rewarding it. We study the effect of sharing a reward among cooperators in the most stringent form of social dilemma.
Replicator dynamics of reward & reputation in public goods games
Journal of Theoretical Biology, 2010
Public goods games have become the mathematical metaphor for game theoretical investigations of cooperative behavior in groups of interacting individuals. Cooperation is a conundrum because cooperators make a sacrifice to benefit others at some cost to themselves. Exploiters or defectors reap the benefits and forgo costs. Despite the fact that groups of cooperators outperform groups of defectors, Darwinian selection or utilitarian principles based on rational choice should favor defectors. In order to overcome this social dilemma, much effort has been expended for investigations pertaining to punishment and sanctioning measures against defectors. Interestingly, the complementary approach to create positive incentives and to reward cooperation has received considerably less attention-despite being heavily advocated in education and social sciences for increasing productivity or preventing conflicts. Here we show that rewards can indeed stimulate cooperation in interaction groups of arbitrary size but, in contrast to punishment, fail to stabilize it. In both cases, however, reputation is essential. The combination of reward and reputation result in complex dynamics dominated by unpredictable oscillations.
Social diversity promotes the emergence of cooperation in public goods games
Nature, 2008
Humans often cooperate in public goods games 1-3 and situations ranging from family issues to global warming 4,5 . However, evolutionary game theory predicts 4,6 that the temptation to forgo the public good mostly wins over collective cooperative action, and this is often also seen in economic experiments 7 . Here we show how social diversity provides an escape from this apparent paradox. Up to now, individuals have been treated as equivalent in all respects 4,8 , in sharp contrast with real-life situations, where diversity is ubiquitous. We introduce social diversity by means of heterogeneous graphs and show that cooperation is promoted by the diversity associated with the number and size of the public goods game in which each individual participates and with the individual contribution to each such game. When social ties follow a scale-free distribution 9 , cooperation is enhanced whenever all individuals are expected to contribute a fixed amount irrespective of the plethora of public goods games in which they engage. Our results may help to explain the emergence of cooperation in the absence of mechanisms based on individual reputation and punishment 10-12 . Combining social diversity with reputation and punishment will provide instrumental clues on the self-organization of social communities and their economical implications.
Competition among cooperators: Altruism and reciprocity
2002
Levine argues that neither self-interest nor altruism explains experimental results in bargaining and public goods games. Subjects' preferences appear also to be sensitive to their opponents' perceived altruism. Sethi and Somanathan provide a general account of reciprocal preferences that survive under evolutionary pressure. Although a wide variety of reciprocal strategies pass this evolutionary test, Sethi and Somanthan conjecture that fewer are likely to survive when reciprocal strategies compete with each other. This paper develops evolutionary agent-based models to test their conjecture in cases where reciprocal preferences can differ in a variety of games. We confirm that reciprocity is necessary but not sufficient for optimal cooperation. We explore the theme of competition among reciprocal cooperators and display three interesting emergent organizations: racing to the ''moral high ground,'' unstable cycles of preference change, and, when we implement reciprocal mechanisms, hierarchies resulting from exploiting fellow cooperators. If reciprocity is a basic mechanism facilitating cooperation, we can expect interaction that evolves around it to be complex, non-optimal, and resistant to change.