The Independent Localisations of Interaction and Learning in the Repeated Prisoner's Dilemma

The results of a series of computer simulations demonstrate how the introduction of separate spatial dimensions for agent interaction and learning respectively affects the possibility of cooperation evolving in the repeated prisoner's dilemma played by populations of boundedly-rational agents. In particular, the localisation of learning promotes the emergence of cooperative behaviour, while the localisation of interaction has an ambiguous effect on it.     

Prisoner's dilemma from a moral point of view

In a recent issue of this journal, C. L. Sheng claims to havesolved andexplained the Prisoner's Dilemma (PD) by studying it from a moral point of view - i.e., by assuming that each player feels sympathy for the other. Sheng does not fully clarify this claim, but there is textual evidence that his point is this: PD's arise only for agents who feel little or no sympathy for each other; they cannot arise in the presence of a high degree of reciprocal sympathy. A high degree of such sympathysolves the PD in that it prevents PD's from arising, and a low degree of itexplains the PD in that it provides an essential condition for the occurrence of that game. This thesis is false, as some examples show. These examples are important; they prevent us from underestimating the problem posed by the PD.     

Effective choice in the single-shot Prisoner's Dilemma tournament

This paper discusses the results of a single-shot Prisoner's Dilemma computer tournament. In the single-shot Prisoner's Dilemma tournament each pair of players interacts only once. But players can establish and detect reputations because they know how their current opponent has behaved in previous games with other players. The results show that cooperation is worthwhile, even in single-shot games, provided the outcomes of previous games are common knowledge.Reality is a game, but you shouldn't take a game for reality(Pragmaticist Proverb)     

金融危机下中国创业投资“囚徒困境”演化研究

创业投资家和创业企业家的＂囚徒困境＂是制约中国创业投资进一步发展的主要障碍之一。对短期利益的追求和缺乏信任是造成中国创业投资＂囚徒困境＂的两个重要原因。在金融危机背景下,＂囚徒困境＂的演化将朝着有利于创业投资家的方向发展。金融危机虽然能改变博弈的结果,却未能改变＂囚徒困境＂的成因。     

For Bayesian Wannabes,Are Disagreements Not About Information?

Consider two agents who want to be Bayesians with a common prior, but who cannot due to computational limitations. If these agents agree that their estimates are consistent with certain easy-to-compute consistency constraints, then they can agree to disagree about any random variable only if they also agree to disagree, to a similar degree and in a stronger sense, about an average error. Yet average error is a state-independent random variable, and one agent's estimate of it is also agreed to be state-independent. Thus suggests that disagreements are not fundamentally due to differing information about the state of the world.     

Multiple Prisoner's Dilemma Games with(out) an Outside Option: an Experimental Study

Experiments in which subjects play simultaneously several finite two-person prisoner's dilemma supergames with and without an outside option reveal that: (i) an attractive outside option enhances cooperation in the prisoner's dilemma game, (ii) if the payoff for mutual defection is negative, subjects' tendency to avoid losses leads them to cooperate; while this tendency makes them stick to mutual defection if its payoff is positive, (iii) subjects use probabilistic start and endeffect behavior.     

Biting the Bayesian bullet: Zeckhauser's problem

A troubling challenge to the basic principles of Bayesian decision theory is analyzed as a case where irrationality is no intellectual flaw but a characterological one, i.e., not stupidity but funk.     

Pavlov and the prisoner's dilemma

Our Pavlov learns by conditioned response, through rewards and punishments, to cooperate or defect. We analyze the behavior of an extended play Prisoner's Dilemma with Pavlov against various opponents and compute the time and cost to train Pavlov to cooperate. Among our results is that Pavlov and his clone would learn to cooperate more rapidly than if Pavlov played against the Tit for Tat strategy. This fact has implications for the evolution of cooperation.     

Folk theorems for the observable implications of repeated games

The fact that infinitely repeated games have many different equilibrium outcomes is known as the Folk Theorem. Previous versions of the Folk Theorem have characterized only the payoffs of the game. This paper shows that over a finite portion of an infinitely repeated game, the concept of perfect equilibrium imposes virtually no restrictions on observable behavior. The Prisoner's Dilemma is presented as an example and discussed in detail.I would like to thank an anonymous referee, Sushil Bikhchandani, David Hirshleifer, David Levine, Thomas Voss, and participants in the UCLA Game Theory Seminar for helpful comments.     

The repeated public goods game: A solution using Tit-for-Tat and the Lindahl point

This paper demonstrates how a repeated public goods problem may be solved by using Tit-for-Tat (TFT) on the Lindahl point. The general solution is developed; geometric and numerical examples are offered.I wish to thank an anonymous reviewer for very helpful comments on earlier drafts of this paper.     

Learning to cooperate with Pavlov an adaptive strategy for the iterated Prisoner's Dilemma with noise

Conflict of interest may be modeled, heuristically, by the iterated Prisoner's Dilemma game. Although several researchers have shown that the Tit-For-Tat strategy can encourage the evolution of cooperation, this strategy can never outscore any opponent and it does poorly against its clone in a noisy environment. Here we examine the family of Pavlovian strategies which adapts its play by positive and negative conditioning, much as many animals do. Mutual cooperation will evolve in a contest with Pavlov against a wide variety of opponents and in particular against its clone. And the strategy is quite stable in a noisy environment. Although this strategy cooperates and retaliates, as does Tit-For-Tat, it is not forgiving; Pavlov will exploit altruistic strategies until he is punished by mutual defection. Moreover, Pavlovian strategies are natural models for many real life conflict-of-interest encounters as well as human and computer simulations.     

Towards a Lacanian Group Psychology: The Prisoner's Dilemma and the Trans‐subjective

Revisiting Lacan's discussion of the puzzle of the prisoner's dilemma provides a means of elaborating a theory of the trans‐subjective. An illustration of this dilemma provides the basis for two important arguments. Firstly, that we need to grasp a logical succession of modes of subjectivity: from subjectivity to inter‐subjectivity, and from inter‐subjectivity to a form of trans‐subjective social logic. The trans‐subjective, thus conceptualized, enables forms of social objectivity that transcend the level of (inter)subjectivity, and which play a crucial role in consolidating given societal groupings. The paper advances, secondly, that various declarative and symbolic activities are important non‐psychological bases—trans‐subjective foundations—for psychological identifications of an inter‐subjective sort. These assertions link interesting to recent developments in the contemporary social psychology of interobjectivity, which likewise emphasize a type of objectivity that plays an indispensible part in co‐ordinating human relations and understanding.     

Backward Induction Is Not Robust: The Parity Problem and the Uncertainty Problem

A cornerstone of game theory is backward induction, whereby players reason backward from the end of a game in extensive form to the beginning in order to determine what choices are rational at each stage of play. Truels, or three-person duels, are used to illustrate how the outcome can depend on (1) the evenness/oddness of the number of rounds (the parity problem) and (2) uncertainty about the endpoint of the game (the uncertainty problem). Since there is no known endpoint in the latter case, an extension of the idea of backward induction is used to determine the possible outcomes. The parity problem highlights the lack of robustness of backward induction, but it poses no conflict between foundational principles. On the other hand, two conflicting views of the future underlie the uncertainty problem, depending on whether the number of rounds is bounded (the players invariably shoot from the start) or unbounded (they may all cooperate and never shoot, despite the fact that the truel will end with certainty and therefore be effectively bounded). Some real-life examples, in which destructive behavior sometimes occurred and sometimes did not, are used to illustrate these differences, and some ethical implications of the analysis are discussed.     

Utility theory and the Bayesian paradigm

In this paper, a problem for utility theory - that it would have an agent who was compelled to play Russian Roulette with one revolver or another, to pay as much to have a six-shooter with four bullets relieved of one bullet before playing with it, as he would be willing to pay to have a six-shooter with two bullets emptied - is reviewed. A less demanding Bayesian theory is described, that would have an agent maximize expected values of possible total consequence of his actions. And utility theory is located within that theory as valid for agents who satisfy certain formal conditions, that is, for agents who are, in terms of that more general theory, indifferent to certain dimensions of risk. Raiffa- and Savage-style arguments for its more general validity are then resisted. Addenda are concerned with implications for game theory, and relations between utilities and values.     

Countable Additivity and the Foundations of Bayesian Statistics

At a very fundamental level an individual (or a computer) can process only a finite amount of information in a finite time. We can therefore model the possibilities facing such an observer by a tree with only finitely many arcs leaving each node. There is a natural field of events associated with this tree, and we show that any finitely additive probability measure on this field will also be countably additive. Hence when considering the foundations of Bayesian statistics we may as well assume countable additivity over a σ-field of events.     

边境工业化:“两廊一圈”的困境与出路

针对中越边境出现的逆工业化与“工业低谷”现象,文章运用实地资料及数量方法,实证分析“两廊一圈”工业发展的现状、成因与发展困境,提出通过跨境梯度开发、壮大特产加工、鼓励高新技术等推进边境工业化的可能发展路向。     

Estimation of a Bernouilli parameter: A normative approach to replace the Bayesian one

The paper deals with the problem of the estimation of an unknown probability from a finite number of experiments. We propose a normative (axiomatic) solution that restricts the class of admissible estimators to a one-parameter family. Moreover this solution coincides with the one obtained from Bayes theory with a prior. Thus our results can be interpreted as a justification for the use of Bayesian inference with a prior.     

过渡治理情境下的中国社会服务困境:基于Z市社会工作服务的研究

社会工作近十年来在创新社会治理的推动下发展迅速。本文将重点关注于社会服务组织的服务供给过程及其导致的社会服务困境。通过对治理情境的拓展分析,引入过渡治理情境概念,分析我国社会服务供给。在此情境下,本文以Z市家庭综合服务中心为例,围绕自由裁量权这一概念讨论社会服务组织的服务供给策略及其所导致的服务困境。在过渡治理情境中,消极的自由裁量权与社会工作的半专业化发展结合在一起,社会服务组织选择了“活动化”和“指标化”的服务供给,令社会服务处于创新和碎片化之间,而导致社会服务陷入困境。社会服务困境根源的解决在于建立合作的治理情境、强化本土化社工专业力量以及充分发挥第三方的社会服务供给效力。