Fault tolerance in large games

A Nash equilibrium is an optimal strategy for each player under the assumption that others play according to their respective Nash strategies, but it provides no guarantees in the presence of irrational players or coalitions of colluding players. In fact, no such guarantees exist in general. However, in this paper we show that large games are innately fault tolerant. We quantify the ways in which two subclasses of large games – λ-continuous games and anonymous games – are resilient against Byzantine faults (i.e. irrational behavior), coalitions, and asynchronous play. We also show that general large games have some non-trivial resilience against faults.     

Partial exposure in large games

In this work we introduce the notion of partial exposure, in which the players of a simultaneous-move Bayesian game are exposed to the realized types and chosen actions of a subset of the other players. We show that in any large simultaneous-move game, each player has very little regret even after being partially exposed to other players. If players are given the opportunity to be exposed to others at the expense of a small decrease in utility, players will decline this opportunity, and the original Nash equilibria of the game will survive.     

The lifeboat problem

We study an all-pay contest with multiple identical prizes (“lifeboat seats”). Prizes are partitioned into subsets of prizes (“lifeboats”). Players play a two-stage game. First, each player chooses an element of the partition (“a lifeboat”). Then each player competes for a prize in the subset chosen (“a seat”). We characterize and compare the subgame perfect equilibria in which all players employ pure strategies or all players play identical mixed strategies in the first stage. The partitioning of prizes can lead to coordination failure when players employ nondegenerate mixed strategies. In these equilibria some rents are sheltered and rent dissipation is reduced.     

Reciprocity and Cooperation in Repeated Coordination Games: The Principled-Player Approach

Two long-lived players play a repeated coordination game. I show the restrictions on players' beliefs which imply that cooperation is optimal play. Journal of Economic Literature Classification Number: D83.     

Positional learning with noise

We propose (and test experimentally) a model of observational learning in which players have social preferences. To this end, we design an experiment–based on a classic parlor game known as the Chinos Game–in which we vary (by way of an exogenous iid stochastic process) the probability of getting the prize in the event of a correct guess. By this design, we are able to estimate more efficiently players’ sensitivity to difference in payoffs (and how this sensitivity affects information decoding along the sequence). We also condition our estimates upon additional information on subjects’ socio-demographics, risk attitudes and cognitive reflection by way of a questionnaire that we collect at the end of each session.     

Circadian effects on strategic reasoning

The ability to strategically reason is important in many competitive environments. In this paper, we examine how relatively mild temporal variations in cognition affect reasoning in the Beauty Contest. The source of temporal cognition variation that we explore is the time-of-day that decisions are made. Our first result is that circadian mismatched subjects (i.e., those making decisions at off-peak time of day) display lower levels of strategic reasoning in the p<1 Beauty Contest but not in the p>1 game. This suggests that a cognitively more challenging environment is required for circadian mismatch to harm strategic reasoning. A?second result is that choice adaptation or mimicry (i.e., a?more automatic type of responding than what is typically considered to be “learning”) during repeated play is not significantly affected by circadian mismatch. This is consistent with the hypothesis that automatic thought is more resilient to cognitive resource depletion than controlled-thought decision making.     

Let׳s talk it over: Coordination via preplay communication with level-k thinking

This paper reconsiders Farrell׳s (1987) and Rabin׳s (1994) analyses of coordination via preplay communication, focusing on Farrell׳s analysis of Battle of the Sexes. Replacing their equilibrium and rationalizability assumptions with a structural non-equilibrium model based on level-k thinking, I reevaluate Farrell and Rabin׳s assumptions on how players use language and their conclusions on the limits of communication in bringing about coordination. The analysis partly supports their assumptions about how players use language, but suggests that their “agreements” do not reflect a full meeting of the minds. A level-k analysis also yields very different conclusions about the effectiveness of communication.     

Coordination and Information in Critical Mass Games: An Experimental Study

We present experimental results on a repeated coordination game with Pareto-ranked equilibria in which a payoff from choosing an action is positive only if a critical mass of players choose that action. We design a baseline version of the game in which payoffs remain constant for values above the critical mass, and an increasing returns version in which payoffs keep increasing for values above the critical mass. We test the predictive power of security and payoff-dominance under different information treatments. Our results show that convergence to the payoff-dominant equilibrium is the modal limit outcome when players have full information about others' previous round choices, while this outcome never occurs in the remaining treatments. The paths of play in some groups reveal a tacit dynamic coordination by which groups converge to the efficient equilibrium in a step-like manner. Moreover, the frequency and speed of convergence to the payoff-dominant equilibrium are higher, ceteris paribus, when increasing returns are present. Finally, successful coordination seems to crucially depend on players' willingness to signal to others the choice of the action supporting the efficient equilibrium.     

Monotone Games with Positive Spillovers

A monotone game comprises the infinitely repeated play of an n-person stage game, subject to the constraint that players' actions be monotonically nondecreasing over time. These games represent a variety of strategic situations in which players are able to make (partial) commitments. If the stage games have positive spillovers and satisfy certain other conditions, then the limit points of the subgame perfect equilibria are precisely the approachable action profiles. This characterization is applied to voluntary contribution games, market games, and coordination games. Journal of Economic Literature Classification Number: C7.     

Coordination need not be a problem

In a game of common interest there is one action vector that all players prefer to every other. Yet there may be multiple Pareto-ranked Nash equilibria in the game and the “coordination problem” refers to the fact that rational equilibrium play cannot rule out Pareto-dominated equilibria. In this paper, I prove that two elements — asynchronicity and a finite horizon — are sufficient to uniquely select the Pareto-dominant action vector (in subgame perfect equilibrium play). Asynchronicity may be exogenously specified by the rules of the game. Alternatively, in a game where players choose when to move, asynchronicity may emerge as an equilibrium move outcome.     

创业平台资源警觉、意义给赋与在孵企业机会开发：多重中介模型检验

创业平台应具备何种认知以及如何影响在孵企业机会开发,是孵化资源利用率提升的关键。基于认知领域警觉理论,研究创业平台资源警觉对在孵企业机会开发（创新型和模仿型）的影响,以及意义给赋（直接和间接给赋方式）的多重中介效应。以入驻创业平台的在孵企业为调研样本,通过结构方程模型进行实证检验。结果发现：创业平台资源警觉对在孵企业创新型和模仿型机会开发均具有显著正向影响;意义给赋中的直接和间接给赋在二者间起完全中介作用;直接和间接给赋的中介效应不具有统计上的显著差异。研究结论对于创业平台明确组织角色、优化服务,进而提升孵化资源利用率具有一定指导意义。     

Group play in games and the role of consent in network formation

We study games played between groups of players, where a given group decides which strategy it will play through a vote by its members. When groups consist of two voting players, our games can also be interpreted as network-formation games. In experiments on Stag Hunt games, we find a stark contrast between how groups and individuals play, with payoffs playing a primary role in equilibrium selection when individuals play, but the structure of the voting rule playing the primary role when groups play. We develop a new solution concept, robust-belief equilibrium, which explains the data that we observe. We provide results showing that this solution concept has application beyond the particular games in our experiments.     

Making real money in virtual worlds: MMORPGs and emerging business opportunities, challenges and ethical implications in metaverses

Today, millions of people from around the globe play online role playing games (MMORPG), in which a large number of players interact with one another in a virtual world, either using their existing identities in the physical world, or more often than not, through new virtual identities that might not even be remotely linked to the identities of the players in the physical world. The number of users is growing at an exponential rate and we are probably on the verge of a new development that is going to be as significant as the Internet itself. This positioning paper will discuss the business opportunities and challenges of such a virtual world, that of Second Life, and will examine the resultant corporate social responsibility implications focusing on the ethical and policy-related ones. This will help to identify important research questions that need to be systematically addressed.     

Coordination of strategic responses to security threats: Laboratory evidence

Laboratory experiments are used to evaluate the extent to which players in games can coordinate investments that diminish the probability of losses due to security breaches or terrorist attacks. In this environment, economically sensible investments may be foregone if their potential benefits are negated by failures to invest in security at other sites. The result is a coordination game with a desirable high-payoff, high-security equilibrium and an undesirable low-security equilibrium that may result if players do not expect others to invest in security. One unique feature of this coordination situation is that investment in security by one player generates a positive externality such that all other players’ expected payoffs are increased, regardless of those other players’ investment decisions. Coordination failures are pervasive in a baseline experiment with simultaneous decisions, but coordination is improved if players are allowed to move in an endogenously determined sequence. In addition, coordinated security investments are observed more often when the largest single security threat to individuals is preventable by their own decisions to invest in security. The security coordination game is a “potential game,” and the success of coordination on the more secure equilibrium is related to the notion of potential function maximization and basin of attraction.      

Repeated Games with Almost-Public Monitoring

In repeated games with imperfect public monitoring, players can use public signals to coordinate their behavior, and thus support cooperative outcomes, but with private monitoring, such coordination may no longer be possible. Even though grim trigger is a perfect public equilibrium (PPE) in games with public monitoring, it often fails to be an equilibrium in arbitrarily close games with private monitoring. If a PPE has players' behavior conditioned only on finite histories, then it induces an equilibrium in all close-by games with private monitoring. This implies a folk theorem for repeated games with almost-public almost-perfect monitoring. Journal of Economic Literature Classification Numbers: C72, C73.     

任务复杂性对团队认知影响的案例研究

任务是组织中知识型团队存在的基础,也是团队认知得以涌现并不断发展的内在前提。在诸多任务性质中,复杂性反映了知识型团队的本质。从系统科学出发,将任务复杂性分解为要素维度、互依性维度和可变性维度,以此区分不同的任务类型。选取企业中的知识型团队为研究对象,采用案例研究方法,探讨团队任务复杂性对团队认知结构的作用。结果发现：任务复杂性能够很好地预测团队心智模型,但对交互记忆系统的预测效果较弱。对案例团队展开进一步研究发现,任务复杂性对团队认知结构的作用并非处于真空之中,只有当任务复杂性与团队管理规范相匹配时,团队认知结构才得以涌现。最后,提出知识型团队管理建议。     

Conservative belief and rationality

Playersʼ beliefs may be incompatible, in the sense that player i can assign probability 1 to an event E to which player j assigns probability 0. One way to block incompatibility is to assume a common prior. We consider here a different approach: we require playersʼ beliefs to be conservative, in the sense that all players must ascribe the actual world positive probability. We show that common conservative belief of rationality (CCBR) characterizes strategies in the support of a subjective correlated equilibrium where all playersʼ beliefs have common support. We also define a notion of strong rationalizability, and show that it is characterized by CCBR.     

制度环境与创业认知组态如何驱动不同模式创业

创新创业是推动我国经济转型升级与高质量发展的重要引擎。基于组态视角，整合管制、认知和规范3个制度环境层面前因条件，以及能力感知、机会识别和失败恐惧3个创业认知层面前因条件，以全球创业观察数据库中的51个国家为研究样本，采用模糊集定性比较分析法探讨影响不同创业模式的多重并发条件与因果复杂机制、不同经济体之间的创业模式差异及创业模式演化路径。研究发现：第一，生存型创业驱动机制可划分为制度环境缺失的能力驱动型模式、规范制度主导的机会识别型模式和制度环境缺失的风险承担型模式3种。第二，机会型创业驱动机制可划分为规范制度缺失的创业认知型模式、规范制度引导的机会识别型模式、认知制度支持的创业认知型模式和管制制度保障的能力机会型模式4种。其中，机会识别是驱动机会型创业的关键条件，管制、认知和规范三维制度之间存在替代效应，可以推动高机会识别群体选择机会型创业。第三，要素驱动型经济体以生存型创业为主，部分国家推动机会型创业；效率驱动型经济体同时发展生存型创业和机会型创业，创新驱动型经济体高度重视机会型创业。在此基础上，构建路径选择—模式演化—经济体转型研究框架，为推动生存型创业向机会型创业演化进而向创新驱动型经济体转型升级、助推经济高质量发展提供理论指导和实践启示。     

Individually selecting among conventions - an evolutionary and experimental analysis

Conventions can be narrowly interpreted as coordinated ways of equilibrium play, telling all players which of possibly several equilibria to play or more broadly how to choose in a game without imposing the equilibrium property. Since coordination often takes place before learning about the game, one has to coordinate on a prescribing principle. For the subclass of 2×2-bimatrix games with two strict equilibria, we analyze the evolutionary stability of various such principles. In our experiment, we allow participants to coordinate on principles before playing various games. Based on between-subjects treatments, participants do so being completely (they know neither their role nor the game parameters), partially (they know either their role or the game parameters) ignorant, or with no veil of ignorance (they know their role and the game parameters).     

RISKY VERSUS RISKLESS BARGAINING PROCEDURES: THE AUMANN‐ROTH CONTROVERSY REVISITED*

In a series of papers, Aumann and Roth discussed a game in which players can cooperate in pairs and two of them prefer to form a coalition with each other. Roth argued that the only rational outcome is that the players who prefer each other form a coalition; Aumann argued that all three coalitions are possible because the players have a problem of expectation coordination. A non‐cooperative analysis provides additional support for Aumann's arguments and shows that the difference between Aumann's and Roth's views can be traced back to a difference (risky versus/riskless) in the bargaining procedure.