Efficient and stable collective choices under gregarious preferences

We consider collective choice problems where a set of agents have to choose an alternative from a finite set and agents may or may not become users of the chosen alternative. An allocation is a pair given by the chosen alternative and the set of its users. Agents have gregarious preferences over allocations: given an allocation, they prefer that the set of users becomes larger. We require that the final allocation be efficient and stable (no agent can be forced to be a user and no agent who wants to be a user can be excluded). We propose a two-stage sequential mechanism whose unique subgame perfect equilibrium outcome is an efficient and stable allocation which also satisfies a maximal participation property.     

Efficient and stable collective choices under gregarious preferences

We consider collective choice problems where a set of agents have to choose an alternative from a finite set and agents may or may not become users of the chosen alternative. An allocation is a pair given by the chosen alternative and the set of its users. Agents have gregarious preferences over allocations: given an allocation, they prefer that the set of users becomes larger. We require that the final allocation be efficient and stable (no agent can be forced to be a user and no agent who wants to be a user can be excluded). We propose a two-stage sequential mechanism whose unique subgame perfect equilibrium outcome is an efficient and stable allocation which also satisfies a maximal participation property.     

Herding with costly information and signal extraction

Costly signal acquisition compels decision-makers to choose between acquiring private signals and following their predecessors, which can result in problems associated with signal extraction. The results show that the information externality of the second decision-maker influences the efficiency of herd behavior among subsequent decision-makers. If the second decision-maker acts differently than his predecessor, the followers take a free ride on his signal acquisition and act correctly. However, if the second investor acts in the same manner as his predecessor, the followers will acquire the costly signals only if the precision of their private signals is significant, otherwise herding is inefficient.     

Herding and bank runs

Traditional models of bank runs do not allow for herding effects, because in these models withdrawal decisions are assumed to be made simultaneously. I extend the banking model to allow a depositor to choose his withdrawal time. When he withdraws depends on his consumption type (patient or impatient), his private, noisy signal about the quality of the bank's portfolio, and the withdrawal histories of the other depositors. Some of these runs are efficient in that the bank is liquidated before the portfolio worsens. Others are not efficient; these are cases in which the herd is misled.     

分析师羊群行为与企业风险承担

本文利用中国沪深两市A股上市公司数据,实证检验了证券分析师羊群行为与企业风险承担的关系,研究发现:分析师羊群行为会削弱企业风险承担。进一步研究表明,加剧信息不对称是分析师羊群行为降低企业风险承担的重要机制。并且,当企业融资约束较高、公司治理较弱时,分析师羊群行为与企业风险承担的负向关系更显著。此外,分析师羊群行为抑制企业风险承担的具体表现形式体现在降低企业创新和债务融资上。本文丰富了企业风险承担影响因素及分析师羊群行为经济后果的文献,有助于深入了解分析师在企业风险选择中发挥的作用。     

Bargaining with history-dependent preferences

Two impatient players bargain over a pie of size one according to the infinite alternating-offers procedure. Players’ payoffs depend not only on the outcome but also on the process of the bargaining. Specifically, they prefer impasse to any agreement that gives them lower discounted utility than would have been derived from accepting earlier offers. We characterize the essentially unique subgame perfect equilibrium path, which consists of gradual concessions. The more patient players are, the longer it takes them to reach an agreement. When players become infinitely patient, the efficiency loss is substantial, yet the equilibrium division converges to the Nash solution.     

Economies with price-dependent preferences

With the exception of existence, not much is known of economies where individual preferences may depend on prices. We show that the main properties of competitive equilibria that fall under the general heading of qualitative comparative statics remain true when preferences are price-dependent, provided that the total resources are allowed to vary in the parameter space. The equilibrium set is a smooth manifold diffeomorphic to a Euclidean space; the natural projection is a smooth proper map, with topological degree one; equilibria always exist, and are locally unique for an open and dense set of economies.     

Market design with endogenous preferences

This paper explores the interdependence between market structure and an important class of cognitive biases. Starting with a familiar bilateral monopoly framework, we characterize the endogenous emergence of preference distortions during bargaining which cause negotiators to perceive their private valuations differently than they would outside the adversarial negotiation context. Using this model, we then demonstrate how a number of external interventions in the structure and/or organization of market interactions (occurring before trade, after trade, or during negotiations themselves) can profoundly alter the nature of these dispositions. Our results demonstrate that many such interventions frequently (though not always) share qualitatively similar characteristics to market interventions that are often proposed for overcoming more conventional forms of market failure. Nevertheless, our analysis underscores the importance of understanding the precise link between cognitive failures and market structure prior to the implementation of any particular proposed reform.     

Distributive politics with other-regarding preferences

This paper analyzes a nonsmooth model of probabilistic voting with two parties and a broad family of other-regarding behavior, including fairness and quasi-maximin preferences, income-dependent altruism, and inequity aversion. The paper provides conditions for equilibrium existence and uniqueness. It also characterizes the Nash equilibrium in pure strategies when parties hold either symmetric payoffs, or minor forms of asymmetries. The characterization shows that the two parties converge to an equilibrium policy that maximizes a mixture of a “self-regarding utilitarian” social welfare function and an aggregate of society's other-regarding preferences. These results are shown to be applicable to other nonsmooth frameworks, such as probabilistic voting with loss averse voters. The characterization also shows that the direction and the size of the inefficiencies emerging from electoral competition depend in a subtle way on the nature of the other-regarding preferences (and resp., loss aversion).     

Nonlinear pricing with self-control preferences

A basic assumption of economics is that consumers choose what they want. However, many consumers find it difficult to stop overeating, overspending, smoking, procrastinating, etc, even though they want to. In reality, consumers have temptation and it is psychologically costly to exercise self-control. To clarify the implications of the existence of temptation and self-control costs, this paper studies a firm's optimal selling strategy exploiting the behavioral features of consumers. We characterize optimal nonlinear pricing schemes for a monopoly when self-control is costly for consumers. Since consumers have a preference for commitment, the firm faces a trade-off between offering a small menu that makes the consumers’ self-control easier and offering a large menu that achieves better price discrimination. We show that the optimal menu resembles the one in the standard nonlinear pricing problem with a price ceiling, where the upper bound on prices is determined endogenously by a participation constraint. The ceiling motivates the firm to offer a relatively flat and compact price schedule, serving more consumers with low demand. The characterization also shows that the firm may earn less if consumers have temptation.     

Increasing risk with state-dependent preferences

A definition of increasing risk for state-dependent preferences is introduced and its usefulness for the analysis of concrete economic problems is illustrated. For classes of individuals with the same reference set the notion of increasing risk has three equivalent characterizations analogous to those obtained in the case of state-independent preferences. The definition is used to conduct a comparative statics analysis of a portfolio problem with state-dependent preferences.     

Repeated games with present-biased preferences

We study infinitely repeated games with perfect monitoring, where players have β-δ preferences. We compute the continuation payoff set using recursive techniques and then characterize equilibrium payoffs. We then explore the cost of the present-time bias, producing comparative statics. Unless the minimax outcome is a Nash equilibrium of the stage game, the equilibrium payoff set is not monotonic in β or δ. Finally, we show how the equilibrium payoff set is contained in that of a repeated game with smaller discount factor.     

A Social-Psychological Perspective on Herding in Stock Markets

A social-psychological perspective conceives of herding in stock markets as informative social influence resulting from heuristic or systematic information processing. In three laboratory experiments employing undergraduates we apply this perspective to investigate factors that prevent herd influence that would lead to inaccurate predictions of stock prices. In Experiment 1, we show that an economic reward for making the same predictions as the herd increases the influence of a majority but not the influence of a minority, and that an individual economic reward for making accurate predictions reduces the influence of the majority. In Experiment 2, we show a reduced influence of a majority herd's inaccurate predictions when requiring assessments of the accuracy of the majority herd´s predictions as compared to requiring judgments of their consistency. Experiment 3 shows that a lower volatility of stock prices reduces the influence of a majority herd´s inaccurate predictions.     

羊群效应对股指波动率的影响分析

投资者行为对资本市场的稳定性影响是行为金融学关注的热点问题之一。本文以浦发银行股票为研究对象,首先,利用羊群行为的程度作为度量羊群行为的数量标准,通过建立ARCH模型,对浦发银行股票是否存在羊群效应进行统计检验,结果表明浦发银行股票存在显著的羊群效应。其次,通过建立线性回归模型分析了羊群行为对股票波动性的影响。实证研究表明,股票的羊群行为程度与股票指数波动率成正相关关系。     

Finitely repeated games with social preferences

A well-known result from the theory of finitely repeated games states that if the stage game has a unique equilibrium, then there is a unique subgame perfect equilibrium in the finitely repeated game in which the equilibrium of the stage game is being played in every period. Here I show that this result does in general not hold anymore if players have social preferences of the form frequently assumed in the recent literature, for example in the inequity aversion models of Fehr and Schmidt (Quartely Journal of Economics 114:817–868, 1999) or Bolton and Ockenfels (American Economic Review 100:166–193, 2000). In fact, repeating the unique stage game equilibrium may not be a subgame perfect equilibrium at all. This finding should have relevance for all experiments with repeated interaction, whether with fixed, random or perfect stranger matching.     

Optimal contract theory with time-inconsistent preferences

This paper incorporates managers' time-inconsistent preferences into the classical DeMarzo and Sannikov (2006) contract model to study corresponding impacts on the optimal contract, corporate financial policies, and the optimal capital structure. The extended model shows that the impatience of the time-inconsistent agent has positive effects on the optimal payout decision which is opposite to DeMarzo and Sannikov (2006) and consequently provides a guideline to tailor the contract between investors and the agent. It also shows in the optimal capital structure, the total debt capacity shrinks with the degree of the agent's time inconsistency, and the long-term one shrinks more. In addition, our model predicts that the agent's time inconsistency not only imposes significant limits on the use of long-term debt but also has great effects on firms' capital structures. Thus our finding can potentially explain observed cross-sectional differences in firms' capital structures.     

Optimal stopping with dynamic variational preferences

We solve optimal stopping problems in uncertain environments for agents assessing utility by virtue of dynamic variational preferences as in Maccheroni, Marinacci and Rustichini (2006) [16] or, equivalently, assessing risk in terms of dynamic convex risk measures as in Cheridito, Delbaen and Kupper (2006) [4]. The solution is achieved by generalizing the approach in Riedel (2009) [21] introducing the concept of variational supermartingales and variational Snell envelopes with an accompanying theory. To illustrate results, we consider prominent examples: dynamic multiplier preferences and a dynamic version of generalized average value at risk introduced in Cheridito and Tianhui (2009) [5].     

Optimality of workfare with heterogeneous preferences

With the standard non-linear income taxation framework with heterogeneity of preferences, in this paper the optimality of workfare as a screening tool is examined. It is assumed that workfare does not serve as a human capital investment, participation is mandatory, and administrative costs are negligible. Imposing alternative cardinalizations on individuals utilities allows for the possibility that the government optimally redistributes income to or from high disutility of labour individuals. Under either case, it is never optimal to impose workfare on these individuals. It is also shown that non-productive workfare can be an efficient policy tool, in contrast to the results found in Besley and Coate (1995), Brett (1998), and Beaudry and Blackorby (1997). JEL Classification: H21, H23
Optimalité du workfare en présence de préférences hétérogènes. L'auteur examine l'timalité du workfare en tant qu'instrument de tamisage à l'aide du cadre conceptuel traditionnel d'imposition non-linéaire des revenus en présence de préférences hétérogènes. On postule que le workfare n'est pas un processus d'investissement en capital humain, que la participatioun est obligatoire, et que les coûts d'administration sont négligeables. Quand on postule aussi des utilités cardinales différentes pour les individus, il devient possible pour le gouvernement de redistribuer optimalement les revenus en faveur ou au détriment des individus pour qui le travail a une très grande désutilité. Dans l'un et l'autre cas, on montre que le workfare n'est jamais une politique optimale. On montre aussi que le workfare dans des activités non-productives peut être un instrument de politique publique efficient, contrairement a ce qu'affirment Besley et Coate (1995), Brett (1998) et Beaudry et Blackorby (1997).     

Overriding consumer preferences with energy regulations

The recent wave of enacted and proposed U.S. energy regulations imposes energy efficiency standards on light bulbs, appliances, and motor vehicles based on the unsupported assumption that consumers and firms are irrational and that energy efficiency should be the paramount concern. The regulatory analyses do not document these purported failures in consumer choices or firms’ energy utilization decisions with any empirical evidence. The preponderance of the benefits that agencies claim for the regulations is derived from private benefits to consumers and firms attributable to lower energy costs. Without these benefits, the regulatory costs would greatly exceed the benefits. The regulatory analyses consider only mandates as a means of achieving energy-efficiency improvements and ignore other policy options.     

Weighted congestion games with separable preferences

Players in a congestion game may differ from one another in their intrinsic preferences (e.g., the benefit they get from using a specific resource), their contribution to congestion, or both. In many cases of interest, intrinsic preferences and the negative effect of congestion are (additively or multiplicatively) separable. This paper considers the implications of separability for the existence of pure-strategy Nash equilibrium and the prospects of spontaneous convergence to equilibrium. It is shown that these properties may or may not be guaranteed, depending on the exact nature of player heterogeneity.