Bayesian learning in social networks

We extend the standard model of social learning in two ways. First, we introduce a social network and assume that agents can only observe the actions of agents to whom they are connected by this network. Secondly, we allow agents to choose a different action at each date. If the network satisfies a connectedness assumption, the initial diversity resulting from diverse private information is eventually replaced by uniformity of actions, though not necessarily of beliefs, in finite time with probability one. We look at particular networks to illustrate the impact of network architecture on speed of convergence and the optimality of absorbing states. Convergence is remarkably rapid, so that asymptotic results are a good approximation even in the medium run.     

An experimental test of observational learning under imperfect information

Summary. Nearly all observational learning models assume that individuals can observe all the decisions that have previously been made. In reality, such perfect information is rarely available. To explore the difference between observational learning under perfect and imperfect information, this paper takes an experimental look at a situation in which individuals learn by observing the behavior of their immediate predecessors. Our experimental design uses the procedures of Çelen and Kariv [9] and is based on the theory of Çelen and Kariv [10]. We find that imitation is much less frequent when subjects have imperfect information, even less frequent than the theory predicts. Further, while we find strong evidence that under perfect information a form of generalized Bayesian behavior adequately explains behavior in the laboratory, under imperfect information behavior is not consistent even with this generalization of Bayesian behavior.Received: 29 January 2002, Revised: 12 May 2004, JEL Classification Numbers: C92, D8. Correspondence to: Boaçhan ÇelenWe completed most of this paper when we were both graduate students at New York University. This research was supported by the Center for Experimental Social Sciences (C.E.S.S.) and the C.V. Starr Center for Applied Economics at New York University. We are grateful to Andrew Schotter for his guidance and to an anonymous referee for his comments. We benefited from the expositional suggestions of William Baumol. We also acknowledge helpful discussions of Colin Camerer, Liran Einav, Xavier Gabaix, Douglas Gale, Charles Holt, David Laibson, and Matthew Rabin. We also benefited from suggestions by the participants of the 2002 International ESA Meeting and seminars at several universities.     

Herd behaviour as an incentive scheme

Summary. We consider a set-up in which firms sequentially adopt a technology. The technology is a public good. Late movers, upon observing the early movers adopting the old technology, (partly) infer that the new technology does not exist. This hampers their incentives to innovate. Early movers anticipate this and rather exert effort to try to invent the new technology. Hence, in our model herding reduces free-rider problems and may - in the presence of switching costs - even increase efficiency.Received: 20 June 2002, Revised: 26 May 2004, JEL Classification Numbers: D83, D82, D62.I am very grateful to my thesis advisor Mathias Dewatripont for his many helpful suggestions. I thank seminar participants at ECARES, DELTA, IAE, GREMAQ and WZB. I also benefited from comments made by A.Banerjee, P.Bolton, M.Castanheira, J.Gyntelberg, P.Legros, G.Roland, M.Ruckes, X.Vives, J.Zwiebel and an anonymous referee. I gratefully acknowledge financial assistance provided by the European Commission through its TMR program (Contract number FMRX-CT98-0203) and from the Inter University Poles of Attraction Program (Contract PAI P4/28). Finally, I am also very grateful to M.Castanheira for his many encouragements at the start of my research work.     

垄断行业工资改革的可行性研究——基于国际垄断行业视角

在垄断行业中,员工的工资一般高于其他行业,表现出收入分配的不平等.引起垄断行业工资问题的原因很多,垄断行业工资问题也对社会经济各方面产生着重要影响,导致公共福利受损,减少了劳动者的流动及其对人力资本的投入,加剧了社会收入的不公平.对于垄断行业工资所引发的种种问题已经受到社会各界的重视,各国政府已开始采取措施解决这些问题,把竞争机制等改革引入垄断行业.     

A note on the value of public information in monopoly

The paper shows that in the standard model of monopoly with asymmetric information and second-degree price discrimination, the monopolist prefers to reveal public information under a form of stochastic dependence that is weaker than the affiliation of private values, private signals, and public signals.      

行政垄断、寻租与腐败——转型经济的腐败机理分析

本文试图利用寻租经济学的方法,对中国渐进转型过程中所产生的特有的腐败形式——行政垄断的本质、成因、形式、特征进行了分析;基于现有对转型经济中腐败现象的研究,提出了转型经济中腐败现象的新的分类;并对行政垄断,主要是行业垄断的经济损失规模及租金的耗散等问题进行了初步的研究;最后,回顾了中国反垄断改革的进展,并提出了进一步改革的议程。     

我国基金羊群行为:测度与影响因素

本文以1998年第1季度至2003年第4季度在沪深两市交易的94家基金的投资组合明细数据为样本,借鉴LSV思想构造新的羊群行为测度指标,探讨了我国基金投资者羊群行为的特征及其形成机制。研究发现:基金的羊群行为受到时间、季节、市场规模、基金规模、市场态势和基金盈利水平等因素的影响;羊群行为测度与基金盈利能力、基金/市场的相对规模等因素正相关;熊市中的羊群行为测度值大于牛市中的测度值;基金的羊群行为随着时间的进程没有显著改善,但每年的第2和第3季度是高发期。作者认为,基金在交易模式演变过程中产生的“代表性心理”,以及“心理阻抗”和“控制幻觉”加剧了羊群行为。     

Dynamics of social trust and human capital in the learning process: The case of the Japan garment cluster in the period 1968–2005

This paper examined the ways and the extent to which human capital and social trust are associated with the learning process of a manager in making operations decisions through experience. To this end, using a data set originally and purposively constructed by the author, I investigated the development and transformation of the garment industry cluster region of Kojima, Japan. The major findings through statistical estimations are as follows. (1) In the cluster development stage, the social trust of an enterprise and its manager's experiences in firm operations could be regarded as forming a complementary association. (2) In the stage following cluster development, however, a manager's human capital as accumulated through schooling and personal experience, instead of social trust, become complementary.     

Group polarization in the team dictator game reconsidered

While most papers on team decision-making find that teams behave more selfishly, less trustingly and less altruistically than individuals, Cason and Mui (1997) report that teams are more altruistic than individuals in a dictator game. Using a within-subjects design we re-examine group polarization by letting subjects make individual as well as team decisions in an experimental dictator game. In our experiment teams are more selfish than individuals, and the most selfish team member has the strongest influence on team decisions. Various explanations for the different findings in Cason and Mui (1997) and in our paper are discussed.      

金融市场中的从众行为与信息传播

目前,很多的理论和实证研究发现,从众现象是导致金融市场剧烈波动的重要原因之一。因此,认识从众行为的演变发展过程,分析产生从众现象的原因,并提出一些防范措施是非常有意义的工作。从众现象非常复杂,从信息传播的角度分析从众行为。     

中国民间商会研究述评

当代中国正在经历着一场深刻的社会转型.随着总体性向分散性社会形态的演变以及治道模式由统治向治理的变革,其所导致的标志性成果便是社会结构的变迁和社会组织功能的重塑.作为新兴的公共管理主体,民间商会是市场经济发展和政府职能转变的产物,在地方治理中发挥着提供服务、反映诉求、规范行为等多项功能,从而有效的弥补着市场和政府的双重失灵.然而就已有对民间商会的研究成果分析,却客观存在着数量偏少、视角狭窄、深度欠缺和方法单一等弊端,很大程度上难以为民间商会职能运行提供有效地理论指导和智力支持,也与民间商会日益重要的治理地位无法匹配.为此就必须对现有的研究成果进行梳理和评估,并在分析其理论研究缺失的基础上,找准民间商会理论探索目标和创新方向,通过科学地拓展研究视阈、合理地界定研究概念、规范地使用研究方法,最终指导和确保民间商会良性、健康之发展.     

我国城市公共空间建设问题检讨--基于城镇化质量的分析视角

良好的城市公共空间可以有效提升居民生活品质、塑造公共意识、促进产城融合,因而成为城镇化质量高低的重要体现。人与地、人与人的和谐以及“人的现代化”是城镇化质量的应有之义。据此评判,我国城市公共空间建设还存在一系列问题,主要表现为：规划理念落后,供求矛盾突出;追求宏大平整,破坏自然肌理;割裂历史文脉,丧失文化个性;突出审美价值,忽视人文关怀;排斥弱势群体,加剧社会隔离等。据此,政府应把政策干预的重点放在四个方面,即挖掘私人资本与资源,构建完善的公共空间体系;增强文化自觉与自信,形成个性鲜明的公共空间;转变设计理念,强化公共空间的人文关怀;发挥非政府机构作用,建立公共空间的大众参与机制。     

Accounting for the impact of higher order moments in foreign equity option pricing model

This paper investigates the pricing of foreign equity option whose value depends on foreign equity prices and exchange rate. We assume that the underlying asset returns of foreign equity option is not a Brownian motion, and use the Gram-Charlier series expansion to augment a normal density with two additional terms to capture the effects of skewness and kurtosis. The empirical study shows that the higher order moments (skewness and kurtosis) clearly affect the estimated prices of foreign equity options. This approach enables us to capture more accurately the foreign equity option prices.     

财政支出维稳倾向影响社会稳定形势的实证研究——来自中国省际面板数据的考证

笔者使用中国省际面板数据,运用Granger就财政支出对社会稳定的影响进行非因果性检验发现公共安全财政支出是社会稳定的单向Granger原因,表明以公共安全财政支出变量变化预测社会稳定形势具有显著的统计学意义。鉴于此,公共安全财政支出安排应参照社会稳定形势变化进行动态调整,使其契合中国社会对公共安全保障要求。     

Full-cost pricing in the classical competitive process: A model of convergence to long-run equilibrium

In the last 10–15 years a lot of attempts has been devoted to study the calssical process of convergence of market prices toward natural prices. The two forces that one has thought could achieve this target were capital mobility, that determines the dynamics of output, and demand-supply forces, that determine the dynamics of prices. In this article a model of classical competition is proposed in which a full-cost pricing mechanism is adopted in the rule of evolution of market prices. An asymptotical stability result of long-run equilibrium is proved for a two-commodity model with and without a final demand.     

On the Feasibility of a Liberal Welfare State: Agency and Exit Costs in Income Security Clubs

This paper investigates whether individuals might voluntarily join and remain members of a state in which high levels of social insurance are provided. That is to say, are there plausible circumstances in which a social welfare state can be regarded as “liberal” in the sense that it has the universal support of its citizens?As a point of departure, the paper demonstrates that risk-averse individuals in a setting of substantial income or health uncertainty will voluntarily join private income-security clubs. Private income-security clubs, however, cannot be entirely voluntary because they must solve the problem of adverse selection, as with entry or exit fees. The paper demonstrates that individuals may opt for governmental provision of income security services, when there is uncertainty about the quality of private club services, because naturally high exit costs allow national governments to economically address the problem of adverse selection. The analysis also suggests that liberal income security programs may have constitutional or quasi-constitutional status because of the nature of the long-term nature of the insurance contract.     

Non-myopic learning in differential information economies: the core

Summary. We study the process of learning in a differential information economy, with a continuum of states of nature that follow a Markov process. The economy extends over an infinite number of periods and we assume that the agents behave non-myopically, i.e., they discount the future. We adopt a new equilibrium concept, the non-myopic core. A realized agreement in each period generates information that changes the underlying structure in the economy. The results we obtain serve as an extension to the results in Koutsougeras and Yannelis (1999) in a setting where agents behave non-myopically. In particular, we examine the following two questions: 1) If we have a sequence of allocations that are in an approximate non-myopic core (we allow for bounded rationality), is it possible to find a subsequence that converges to a non-myopic core allocation in a limit full information economy? 2) Given a non-myopic core allocation in a limit full information economy can we find a sequence of approximate non-myopic core allocations that converges to that allocation? Received: May 25, 1999; revised version: August 9, 1999     

The role of credit constraints and government subsidies in farmland valuations in the US: an options pricing model approach

The Modigliani–Miller (M–M) theorem of financial asset theory concludes that asset values are independent of financing. In other words, debt-solvency (credit constraints) does not affect asset values. Therefore, using the M–M theorem one can argue that credit constraints in the farm sector (where land is the most important asset) do not affect the value of farmland. However, this proof relies on several arbitrage assumptions that are violated in the case of agricultural assets. This paper examines the effect of debt-solvency and government payments on changes in annual farmland values by state in the United States. Using panel cointergration method, results indicate that farmland values are significantly affected by both solvency and government payments. In addition, the results imply that government payments may affect agricultural asset values beyond the direct effect hypothesized in the literature.      

A modified logit model for time series with an application to the pricing behaviour of manufacturing firms in Australia

The modified logit model (Amemiya and Nold, 1975) is generalised to the case where the error term is autocorrelated. The asymptotic distribution (as n →∞ and T →∞) of a feasible GLS estimator of β is derived. Tests of linear restrictions on β and the significance of ρ are presented. The results of the applied work suggest that the factors which explain the pricing behaviour of manufacturing firms, as reported in the tendency survey conducted by the Australian Chamber of Commerce and Industry and the Westpac Banking Corporation, include historical inflation rates of up to 7 quarters and capacity utilisation. First version received: March 2001/Final version received: July 2002 RID="*" ID="*"  The first draft of this paper was written while the author was on study leave at the Department of Econometrics, University of Sydney, Australia.     

Run equilibria in the Green–Lin model of financial intermediation

We study the Green–Lin model of financial intermediation [E.J. Green, P. Lin, Implementing efficient allocations in a model of financial intermediation, J. Econ. Theory 109 (2003) 1–23] under a more general specification of the distribution of types across agents. We derive the efficient allocation in closed form. We show that, in some cases, the intermediary cannot uniquely implement the efficient allocation using a direct revelation mechanism. In these cases, the mechanism also admits an equilibrium in which some (but not all) agents “run” on the intermediary and withdraw their funds regardless of their true liquidity needs. In other words, self-fulfilling runs can arise in a generalized Green–Lin model and these runs are necessarily partial, with only some agents participating.