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We study the framing effects of communication on payoffs in multiparty bargaining. Communication has been shown to be more truthful and revealing than predicted in equilibrium. Because talk is preference-revealing, it may effectively frame bargaining around a logic of fairness or competition, moving parties on a path toward or away from equal-division agreements. These endogenous framing effects may outweigh any overall social utility effects due to the mere presence of communication. In two studies, we find that non-binding talk about fairness within a three-party, complete-information game leads toward off-equilibrium, equal division payoffs, while non-binding talk focusing on Competitive Reasoning moves parties away from equal divisions. Our two studies allow us to demonstrate that manipulated pre-game talk and spontaneous within-game dialogue lead to the same results.

We model how student choices to rush a fraternity, and fraternity admission choices, interact with signals firms receive about student productivities to determine labor-market outcomes. The fraternity and students value wages and fraternity socializing values. We provide sufficient conditions under which, in equilibrium, most members have intermediate abilities: weak students apply, but are rejected unless they have high socializing values, while most able students do not apply to avoid taint from association with weaker members. (JEL C72, J24, J31, Z13)

We consider a transaction costs model of sovereign debt buybacks in this paper. We show that both secret and publicly known buybacks are profitable for the debtor country. Furthermore, the government of the debtor country would like to spend all of its initial endowment to buy back its debt as soon as possible. When the initial endowment of the government is publicly known, the equilibrium outcome of the secret buyback model is the same as in the public buyback model. However, the equilibrium outcomes are different when the initial endowment is private information of the government. Under reasonable conditions, the secondary market price under publicly observable buybacks is lower than the price under secret buybacks. Therefore the government prefers the former over the latter when the initial endowment is not commonly known.

This paper considers lifetime employment contracts asa strategic commitment and examines the respectiveequilibrium outcomes of the two cases of a quantity-setting duopoly game with substitute goods and a quantity-setting duopoly game with complementary goods. First, in the quantity-setting game with substitute goods, we Þnd that there is an equilibrium in which both the firms adopt lifetime employment. Next, in the quantity-setting game withcomplementary goods, we Þnd that there is an equilibrium in which at least one Þrm adopts lifetime employment, and that lifetime employment is beneÞcial for both Þrms.

This paper studies the inference of interaction effects in discrete simultaneous games with incomplete information. We propose a test for the signs of state-dependent interaction effects that does not require parametric specifications of players' payoffs, the distributions of their private signals, or the equilibrium selection mechanism. The test relies on the commonly invoked assumption that players' private signals are independent conditional on observed states. The procedure is valid in (but does not rely on) the presence of multiple equilibria in the data-generating process (DGP). As a by-product, we propose a formal test for multiple equilibria in the DGP. We also implement the test using data on radio programming of commercial breaks in the United States, and infer stations' incentives to synchronize their commercial breaks. Our results support the earlier finding by Sweeting (2009) that stations have stronger incentives to coordinate and air commercials at the same time during rush hours and in smaller markets.

This work is based on a differential game proposed by Kelvin Lancaster. The game between two agents called workers and capitalists is based on the accumulation and redistribution of benefits among social classes concluding that cooperative outcomes outperform non-cooperative. This approach determines the optimum solution in a centralized economy as a non-cooperative game and cooperative Pareto solutions forced by the social planner. We compare the model solution in a decentralized economy, where rates economic growth are converging to a steady state and obtain high rates of inflation, and higher levels of consumption. Alternatively, the cooperative solution found between agents can be confirmed. A capitalist game continues to monitor the cooperative principle, in which the maximum benefit is obtained through cooperation.

In this article, we focus on two types of “aversion” which we deem essential aspects of the notion of trust: betrayal aversion (social) and ambiguity aversion (a special case of aversion to uncertainty). Based on trust-games studies in experimental economics and neuroeconomics, our main goal is to assess the conceptual, behavioral and neurobiological connections between betrayal and ambiguity aversions. From a social and individual psychological point of view the bottom line of our trusting behavior could be our general aversion to ambiguous signals. We approach social trust in the terms of a phenomenon based on uncertainty aversion. Specifically, a reduction of the perceived uncertainty of a social interaction tends to build up a trusting climate conducive to trade by decreasing betrayal aversion. We hypothesize that betrayal aversion and ambiguity aversion bear such a negative correlation. Focusing on this potential negative correlation our approach clearly differs from more positive accounts of trust centred on altruism. JEL Classification: C72; C91; D03 ; D87.

This paper analyzes the role of price as a signal of the quality of a monopoly firm's new product. The quality of the goods is drawn from a continuum and is unknown to consumers. We establish a unique separating equilibrium using equilibrium characterization results for signaling games. The equilibrium price monotonically increases with quality levels and exceeds the complete-information monopoly price for all quality levels but the lowest one. However, the upward distortion decreases as the proportion of pre-informed consumers increases. These results extend both the signaling role of price and characteristics of the separating equilibrium as established in Bagwell and Riordan (1991).

A problematic issue in economic theory is the study of price determination. Two distinct approaches to this difficult topic have been taken: (i) in Bertrand competition it is assumed sellers enter the market with a commitment to supply all demand forthcoming from buyers (ii) in Edgeworth competition sellers quote prices with no commitment to supply more than their competitive supply. Both these types of market contract struggle to provide credible pricemaking foundations for perfect competition. In this paper we outline an alternative approach to contract formation with combines Bertrand’s [1883] insight regarding price competition with Edgeworth’s [1881] notion of recontracting. The result is that we can provide a price-making analogue of the Debreu-Scarf [1963] showing that in large markets price-making contracts are ‘close’ to the competitive equilibrium.

In economic situations a player often has preferences regarding not only his or her own outcome but also regarding what happens to fellow players, concerns that are entirely apart from any strategic considerations. While this can be modeled directly by simply writing down a player's final preferences, these are commonly unknown a priori. In many cases it is therefore both helpful and instructive to explicitly model these interactions. This paper, building on a model due to Bergstrom (1989, 1999), presents a simple structure in the context of game theory that incorporates the "synergies" between players. It is powerful enough to cover a wide range of such interactions and model many disparate experimental and empirical results, yet it is straightforward enough to be used in many applied situations where altruism, or a baser motive, is implied.

Lejos de cualquier punto de vista ideologico, nuestro objetivo en este trabajo es estudiar, dentro de un enfoque diferencial de la teoria de juegos, el modelo neoclasico de crecimiento economico. Nuestro modelo base viene de Kaitala y Pohjola (2009) sobre la base de las ideas originales de Lancaster (1973). Nos centramos en el calculo de las estrategias de informacion y el uso de las estrategias historico-dependientes, como las estrategias de gatillo en el que empezar por cooperar y colaborar se da siempre y cuando los rivales lo hacen, pero al observar una desercion de tal situacion implicara entrar de inmediato a un periodo de castigo a longitud especificada en donde todo el mundo juega de forma no-cooperativa. Se demuestra que las estrategias de gatillo son empleadas por ambos grupos, firmas y trabajadores, para mantener la cooperacion como un equilibrio. Entonces llegamos a la conclusion de que las estrategias con memoria de los jugadores son la clave para lograr el maximo crecimiento economico.

El presente trabajo analiza los efectos de los contratos forward y de los contratos de incentivos gerenciales, herramientas que las empresas pueden elegir para competir estratégicamente con sus rivales en un mercado oligopólico. Se encuentra que cuando las dos empresas producen un bien homogéneo, pueden contratar gerentes y negociar contratos forward, en situación de equilibrio ambas empresas contratan gerente y no negocian tales contratos. En el caso de bienes diferenciados, cuando los bienes son sustitutos, las empresas contratan gerente y no negocian contratos forward; cuando los bienes son complementarios, una empresa contrata gerente y no negocia contratos forward y la otra no contrata gerente y negocia contratos forward. El mayor bienestar social se obtiene cuando las empresas utilizan contratos de incentivos gerenciales y contratos forward, y el más bajo se da cuando las empresas no utilizan estas herramientas estratégicas. Sin embargo, el nivel de bienestar social de equilibrio es un subóptimo. This paper analyzes the effects of forward contracts and managerial incentive contracts, which are tools that firms can use to compete strategically with their rivals in an oligopolistic market. The results show that when the two firms produce a homogeneous good, can hire managers and trade forward contracts, in equilibrium they hire managers and none of them negotiate forward contracts. In the case of differentiated goods, when the goods are substitutes, in equilibrium the firms hire managers and do not trade forward contracts; when the goods are complementary, one firm hires a manager and does not negotiate forward contracts whereas the other one does not hire a manager and negotiates forward contracts. The highest social welfare is achieved when the firms use managerial incentive contracts and forward contracts, and the lowest is achieved when the firms do not use these strategic tools. However, the equilibrium social welfare level is suboptimal. Cet article analyse les effets de contrats ''forward'' et des contrats de management. Ces contrats permettent aux entreprises choisir la manière de concurrencier stratégiquement avec ses rivaux sur un marché oligopolistique. Lorsque les deux entreprises produisent un bien homogène, elles peuvent embaucher des gestionnaires et négocier des contrats ''forward''. En équilibre les deux entreprises embauchent un gestionnaire mais elles ne négocient pas de tels contrats. Dans le cas de biens différenciés où les biens sont des substituts, les entreprises embouchent un gestionnaire mais elles ne négocient pas des contrats ''forward''. Lorsque les biens sont complémentaires, une entreprise embouche un gestionnaire mais elle ne négocie pas des contrats ''forward'', tandis que l'autre entreprise ne embouche pas gestionnaire mais négocie contrats ''forward''. Les gains de bien-être sont obtenus lorsque les entreprises utilisent des contrats de management et des contrats ''forward'', et le niveau plus bas de bien-être se produit lorsque les entreprises n'utilisent pas ces outils stratégiques. Cependant, le niveau de bien-être social est un équilibre sous-optimal.

We numerically solve the classical “Game of Pure Strategy” using linear programming. We notice an intricate even-odd behaviour in the results of our computations that seems to encourage odd or maximal bids. peerReviewed

In this study it is demonstrated that standard income inequality measures, such as the Lorenz curve and the Gini index, can successfully be applied to the distribution of Olympic success. Olympic success is distributed very unevenly, with the rich countries capturing a disproportionately higher share compared to their world population share, which suggests that the Olympic Games do not provide a level playing field. The actual distribution of Olympic success is compared with alternative hypothetical distributions, among which are chosen the distribution according to population shares, the welfare optimal distribution under the assumption of zero government expenditures, and the non-cooperating Nash-Cournot distribution. By way of conclusion, a device is proposed to make the distribution of Olympic success more equitable.

This paper explores the scope for synthesis between economic and systemic approaches to the understanding of legal evolution. The evolutionary and epistemic branches of game theory predict that stable norms will emerge when agents share common beliefs concerning future states of the world. Systems theory sees the legal order as a social system which reproduces itself by recursive acts of legal communication, thereby giving rise to self-reference and operational closure. At the same time, the legal system is cognitively open, that is to say, indirectly influenced by other social systems in its environment. This gives rise to the possibility of coevolution of law and the economy. It will be argued that systems theory, by developing the idea of law as an adaptive system with cognitive properties, provides a missing link in the evolutionary theory of norms. Recent game theoretical models imply that common knowledge is not entirely endogenous to agents’ interactions, but depends to a certain extent on emergent normative structures. These include the public representations of common knowledge which are provided by the legal system. The paper will explore the implications of this idea, argue for an integrated economic and systemic analysis of legal evolution, and consider some of the theoretical and methodological implications of such a step.

This paper asks whether population growth is conducive to the sustainability of cooperation. A simple model is developed in which farmers who live around a circular lake engage in trade with their adjacent neighbors. The payoffs from this activity are governed by a prisoner's dilemma "rule of engagement." Every farmer has one son when the population is not growing, or two sons when it is growing. In the former case, the son takes over the farm when his father dies. In the latter case, one son stays on his father's farm, whereas the other son settles around another lake, along with the "other" sons of the other farmers. During his childhood, each son observes the strategies and the payoffs of his father and of the trading partners of his father, and imitates the most successful strategy when starting farming on his own. Then mutant defectors are introduced into an all-cooperator community. The defector strategy may spread. A comparison is drawn between the impact in terms of the sustainability of cooperation of the appearance of the mutants in a population that is not growing, and in one that is growing. It is shown that the ex-ante probability of sustaining the cooperation strategy is higher for a community that is growing than for a stagnant community.

In this paper the problem of optimal derivative design, profit maximization and risk minimization under adverse selection when multiple agencies compete for the business of a continuum of heterogenous agents is studied. The presence of ties in the agents' best-response correspondences yields discontinuous payoff functions for the agencies. These discontinuities are dealt with via efficient tie--breaking rules. In a first step, the model presented by Carlier, Ekeland & Touzi (2007) of optimal derivative design by profit-maximizing agencies is extended to a multiple--firm setting, and results of Page & Monteiro (2003, 2007, 2008) are used to prove the existence of (mixed-strategies) Nash equilibria. On a second step we consider the more complex case of risk minimizing firms. Here the concept of socially efficient allocations is introduced, and existence of the latter is proved. It is also shown that in the particular case of the entropic risk measure, there exists an efficient "fix--mix" tie-breaking rule, in which case firms share the whole market over given proportions., 34 pages and 6 figures

We consider a two-stage voluntary provision model where individuals in a family contribute to a pure public good and/or a household public good, and, at the same time, the parent makes private transfers to her child within the same family. We show not only that Warr’s neutrality holds regardless of the different timings of parent-to-child transfers, but also that there is a continuum of Nash equilibria in the sense that individuals’ contributions and parental transfers are indeterminate, although the allocation of each’s private consumption and total public good provision is uniquely determined. We further show that, even in the presence of impure altruism or productivity difference in supplying public goods, neutrality and uniqueness of the equilibrium allocation may persist.

We report on an experiment using video technology to manipulate pre-play communication protocols in the lab and to study purely social effects of communication on donations and discrimination between potential receivers. The experimental design eliminates strategic factors by allowing two receivers to unilaterally communicate with an anonymous dictator before the latter decides on her gifts. Through the use of three communication setups (none, audio, and audio-visual) we show and analyze the existence of purely social effects of communication. We find that a silent channel leads to discrimination between potential receivers based on impression formation, but does not affect average levels of donations. When the auditory channel is added, average donations increase. The social processes invoked are heterogeneous and communicator- specific but not unsystematic.

Mixed-strategy Nash equilibrium (MSNE) is a commonly-used solution concept in game-theoretic models in various fields in economics, management, and other disciplines, but the experimental results whether the MSNE predicts well actual play in games is mixed. Consequently, evidence for naturally-occurring games in which the MSNE predicts the outcome well is of great importance, as it can justify the vast use of MSNE in models. The game between the kicker and goalkeeper in soccer penalty kicks is a real-world game that can be used to examine the application of the MSNE concept or its accuracy because payoffs are a common knowledge, the players have huge incentives to play correctly, the game is simple enough to analyze, its Nash equilibrium is in mixed strategies, and players' actions can be observed. We collected and analyzed data on the direction of kicks and jumps in penalty kicks in various top leagues and tournaments. Our analysis suggests that the MSNE predictions are the closest to the actual sample data, even though some other prediction methods use information on the marginal distribution of kicks or jumps whereas the MSNE does not.

How do norms of trust and reciprocity arise? We investigate this question by examining behavior in an experiment where subjects play a series of indefinitely repeated trust games. Players are randomly and anonymously matched each period. The parameters of the game are chosen so as to support trust and reciprocity as a sequential equilibrium when no reputational information is available. The main questions addressed are whether a social norm of trust and reciprocity emerges under the most extreme information restriction (community-wide enforcement) or whether trust and reciprocity require additional, individual-specific information about a player’s past history of play and how long that history must be. In the absence of such reputational information, we find that a social norm of trust and reciprocity is difficult to sustain. The provision of reputational information on past individual decisions significantly increases trust and reciprocity, with longer histories yielding the best outcomes. Importantly, we find that making reputational information available at a small cost may also lead to a significant improvement in trust and reciprocity, despite the fact that most subjects do not choose to purchase this information.

In this paper we argue that ambiguity, combined with social opinion formation can be represented as part of a game-theoretic equilibrium concept that transcends the standard Nash equilibrium concept, applied to a model of the tragedy of the commons. Our modeling can shed some light on the international environment crisis and the relevant ongoing international negotiations. We conclude that social opinion formation in most cases has a significant impact on equilibrium common property resource usage.

We propose a semi-cooperative game theoretic approach to check whether a given coalition is stable in a Bayesian game with independent private values. The ex ante expected utilities of coalitions, at an incentive compatible (noncooperative) coalitional equilibrium, describe a (cooperative) partition form game. A coalition is core-stable if the core of a suitable characteristic function, derived from the partition form game, is not empty. As an application, we study collusion in auctions in which the biddersʼ final utility possibly depends on the winnerʼs identity. We show that such direct externalities offer a possible explanation for cartelsʼ structures (not) observed in practice.

Producción Científica, The replicator-mutator dynamics is a set of differential equations frequently used in biological and socioeconomic contexts to model evolutionary processes subject to mutation, error or experimentation. The replicator-mutator dynamics generalizes the widely used replicator dynamics, which appears in this framework as the extreme case where replication is perfectly precise. This paper studies the influence of strictly dominated strategies on the location of the rest points of the replicator-mutator dynamics, at the limit where the mutation terms become arbitrarily small. It can be proved that such limit rest points for small mutation are Nash equilibria, so strictly dominated strategies do not occur at limit stationary points. However, we show through a simple case how strictly dominated strategies can have an influence on the location of the limit rest points for small mutation. Consequently, the characterization of the limit rest points of the replicator-mutator dynamics cannot in general proceed safely by readily eliminating strictly dominated strategies., Junta de Castilla y León (GREX251-2009 y VA006B09), Ministerio de Ciencia e Innovación (TIN2008-06464-C03-02, DPI2010-16920 y CSD2010-00034), Ministerio de Educación (grant JC2009-00263)

We study network formation with n players and link cost \alpha > 0. After the network is built, an adversary randomly deletes one link according to a certain probability distribution. Cost for player v incorporates the expected number of players to which v will become disconnected. We show existence of equilibria and a price of stability of 1+o(1) under moderate assumptions on the adversary and n \geq 9. As the main result, we prove bounds on the price of anarchy for two special adversaries: one removes a link chosen uniformly at random, while the other removes a link that causes a maximum number of player pairs to be separated. For unilateral link formation we show a bound of O(1) on the price of anarchy for both adversaries, the constant being bounded by 10+o(1) and 8+o(1), respectively. For bilateral link formation we show O(1+\sqrt{n/\alpha}) for one adversary (if \alpha > 1/2), and \Theta(n) for the other (if \alpha > 2 considered constant and n \geq 9). The latter is the worst that can happen for any adversary in this model (if \alpha = \Omega(1)). This points out substantial differences between unilateral and bilateral link formation.

We propose an axiomatic approach for equilibrium selection in the discounted, infinitely repeated symmetric Prisoner's Dilemma. Our axioms characterize a unique selection criterion that is also useful as a tool for applied comparative statics exercises as it results in a critical discount factor 6* strictly larger than 6, the standard criterion that has often been used in applications. In an experimental test we find a strong predictive power of our proposed criterion. For parameter changes where the standard and our criterion predict differently, changes in observed cooperation follow predictions based on 8' [JEL C72, C73, C92, D81) which conditions do people cooperate? In this article we study this question in the context of the infinitely repeated Prisoner's Dilemma. Progress in this topic is important for game theory itself, but is also critical for the numerous applications of infinitely repeated games in economics, sociology, political science, biology, and other disciplines. We propose an axiomatic approach that formulates (i) a minimal set of simple and intuitive conditions on the model primitives a sensible selection theory should satisfy and (ii) a more comprehensive set of conditions resulting in a unique cooperation criterion. While the parsimonious formulation (i) has implications for the qualitative question whether cooperation should increase or decrease when parameters change the more specific model (ii) based on a longer list of axioms comes up with a quantified parameter-frontier above which it predicts cooperation. An axiomatic approach can only convince with simple and intuitive axioms that build only on model primitives. The first part of the paper builds intuition for the novel axioms and derives their theoretical implications. The second part presents results from a laboratory experiment testing the implications from both the parsimonious (i) and comprehensive (ii) versions of the theory.

We prove the existence of a trembling-hand perfect equilibrium within a class of compact, metric, and possibly discontinuous games. Our conditions for existence are easily verified in a variety of economic games.

This article discusses interactive minimum cost spanning tree problems and argues that the standard approach of using a transferable utility game to come up with a fair allocation of the total costs has some flaws. A new model of spillover games is presented, in which each player’s decision whether or not to cooperate is properly taken into account.

We show that efficient anonymous incentive compatible (dominant strategy) mechanisms for public goods eliminate externalities, i.e., each individual is unable to change the welfare of anyone else. The characterization is used to derive existence and non-existence results for models with a finite number of individuals and to explain existence results in the continuum. A similar characterization and conclusions are demonstrated for private goods in (J Econ Theory 85:169–225, 1999). However, unlike private goods, elimination of externalities with public goods implies that individuals cannot change the outcome. Hence, such mechanisms provide only weak incentives for truth-telling.

This paper presents the results from a minimum-effort game in which individuals can observe the choices of others in real time. We find that under perfect monitoring almost all groups coordinate at the payoff-dominant equilibrium. However, when individuals can only observe the actions of their immediate neighbors in a circle network, monitoring improves neither coordination nor efficiency relative to a baseline treatment without real-time monitoring. We argue that the inefficacy of imperfect monitoring is due to information uncertainty, that is, uncertainty about the correct interpretation of a neighbor’s actions. Information uncertainty prevents individuals from inferring safely that their group has managed to coordinate from the available information.

The main aim of this article is to investigate the behavioral consequences of the provision of subject-specific information in the group effort levels chosen by players in an experimental CPR game. We examine two basic treatments, one with incomplete information and the other with complete information. In the former, subjects are informed only about their own individual payoffs and the aggregate extraction effort level of the group, and in the latter they are also informed about the individual effort levels and payoffs of each subject. Given this setting, the basic question we attempt to answer is: Will the provision of subject-specific performance information (i.e. individual’s effort levels and payoffs) improve or worsen the tragedy of the commons (i.e. an exploitation effort level greater than the socially optimum level)? In order to motivate our hypotheses and explain our experimental results at the individual level, we make use of the theory of learning in games, which goes beyond standard non-cooperative game theory, allowing us to explore the three basic benchmarks in the commons context: Nash equilibrium, Pareto efficient, and open access outcomes. We use several learning and imitation theoretical models that are based on contrasting assumptions about the level of rationality and the information available to subjects, namely: best response, imitate the average, mix of best response and imitate the average, imitate the best and follow the exemplary learning rules. Finally, in order to econometrically test the hypotheses formulated from the theoretical predictions we use a random-effects model to assess the explanatory power of the different selected behavioral learning and imitation rules. Common Property Resources, Information, Learning and Imitation, Experimental Economics.

Psychological Game Theory (PGT) expands classical game theory allowing for the formal analysis of belief-dependent sentiments and emotions such as resentment, pride, shame, gratefulness and the like. PGT incorporates these factors by relating agents' subjective expected utility to players' strategies, to their beliefs about others' strategies, and also to their beliefs about others' beliefs about their strategies, and so on. This paper argues that, thanks to the epistemic implications of this hierarchy of beliefs, PGT is well-endowed to address, and to some extent solve, three of the most challenging problems recently emerged in classical game theory related respectively to the role of players' intentionality, to the self-fulfilling nature of trust and finally to the so-called social framing effects.

This study compares the representativeness of voters in the proportional electoral system with the situation under plurality rule. Representativeness is commonly measured by comparing parties’ received votes with their shares of seats in the Parliament; this implies that proportional rule should always better represent voters. A coalition within the Parliament, however, rules the country without interference and supports the government; when a coalition is formed, the pivotal role of small parties and the proposal right of the formateur can significantly impact the distribution of power. Focusing on the coalition formation stage, I demonstrate that the proportional rule is more representative only under very specific conditions. If these conditions are not met, introducing some distortions in the distribution of seats among parties can actually improve representativeness.

We analyze the performance of various communication protocols in a generalization of the Crawford-Sobel (1982) model of cheap talk that allows for multiple receivers. We find that whenever the sender can communicate informatively with both receivers by sending private messages, she can communicate informatively by sending public messages. In particular, it is possible that informative communication with one or both receivers is impossible in private, but possible in public. When the sender is allowed to send both public and private messages, it is possible for the sender to combine the commitment provided by public communication with the flexibility provided by private communication and transmit more information to the receivers than under either private or public communication scenarios. When the players can communicate through a mediator and the receivers are biased in the same direction, it is optimal for the sender to communicate with the receivers through independent private noisy communication channels. It is in general optimal to take advantage of pooling the sender’s truthtelling constraints across the receivers when they are biased in the opposite directions.

We propose a computationally feasible way of deriving the identified features of models with multiple equilibria in pure or mixed strategies. It is shown that in the case of Shapley regular normal form games, the identified set is characterized by the inclusion of the true data distribution within the core of a Choquet capacity, which is interpreted as the generalized likelihood of the model. In turn, this inclusion is characterized by a finite set of inequalities and efficient and easily implementable combinatorial methods are described to check them. In all normal form games, the identified set is characterized in terms of the value of a submodular or convex optimization program. Efficient algorithms are then given and compared to check inclusion of a parameter in this identified set. The latter are illustrated with family bargaining games and oligopoly entry games., 54 pages, 23 figures, 2 tables

We submitted three models to the competition which were based on the I-SAW model. The models introduced four new assumptions. In the first model an adjustment process was introduced through which the tendency for exploration was higher at the beginning and decreased over time in the exploration stage. Another new assumption was that surprise as a factor influencing the weight of a trial in the sampling procedure was added. In the second model we added the possibility of an exclusion of unreliable experiences gained in the early trials of a game and the possibility of a revision of a reasonable alternative which was responsible for a very bad outcome in the previous trial. Three of the four added assumptions were combined in the third model. Because each of our models contains at least two new assumptions, we estimated the relative effect of each assumption on the estimation and prediction scores and carried out a test of robustness. In this way, we were able to clarify the usefulness of each added assumption.

We study the following game: each agent i chooses a lottery over nonnegative numbers whose expectation is equal to his budget b_i. The agent with the highest realized outcome wins and agents only care about winning). This game is motivated by various real-world settings where agents each choose a gamble and the primary goal is to come out ahead. Such settings include patent races, stock market competitions, and R&D tournaments. We show that there is a unique symmetric equilibrium when budgets are equal. We proceed to study and solve extensions, including settings where agents must obtain a minimum outcome to win; where agents choose their budgets (at a cost); and where budgets are private information.

Although relative performance schemes are pervasive in organizations, reliable empirical data on induced sabotage behavior are almost nonexistent. We study sabotage in repeated tournaments in a controlled laboratory experiment and observe that effort and sabotage are higher for higher wage spreads. Additionally, we find that also in the presence of tournament incentives, agents react reciprocally to higher wages by exerting higher effort. Destructive activities are reduced by explicitly calling them by their name “sabotage.” Communication among principal and agents can curb sabotage when they agree on flat prize structures and increased output. If sabotage is not possible, the principals choose tournament incentives more often. This paper was accepted by Peter Wakker, decision analysis.

We consider a market for lemons in which the seller is a monopolistic price setter and the buyer receives a private noisy signal of the product’s quality. We model this as a game and analyze perfect Bayesian equilibrium prices, trading probabilities and gains of trade. In particular, we vary the buyer’s signal precision, from being completely uninformative, as in standard models of lemons markets, to being perfectly informative. We show that high quality units are sold with positive probability even in the limit of uninformative signals, and we identify some discontinuities in the equilibrium predictions at the boundaries of completely uninformative and completely informative signals, respectively.

This paper experimentally compares the performance of four simultaneous lottery contests: a grand contest, two multiple prize settings (equal and unequal prizes), and a contest which consists of two subcontests. Consistent with the theory, the grand contest generates the highest effort levels among all simultaneous contests. In multiprize settings, equal prizes produce lower efforts than unequal prizes. The results also support the argument that joint contests generate higher efforts than an equivalent number of subcontests. Contrary to the theory, there is significant over-dissipation. This over-dissipation can be partially explained by strong endowment size effects. Subjects who receive higher endowments tend to over-dissipate, whereas such overdissipation disappears when the endowments are lower. This behavior is consistent with the predictions of a quantal response equilibrium. We also find that less risk-averse subjects over-dissipate more. (JEL C72, C91, D72)

This note studies the problem of implementing social choice correspondences in environments where individuals have doubts about the rationality of their opponents. We postulate the concept of "-minimax regret as our solution concept and show that social choice correspondences that are Maskin monotonic and satisfy the no-veto power condition are implementable in "-minimax regret equilibrium for all " ? [0, 1).

This paper proposes a conception of mutual advantage as a motivation for cooperative behaviour. This motivation is contrasted with the 'emotional' reciprocity that is represented in current theories of social preferences. The paper explores parallels between mutual advantage and Humean analyses of convention, and between mutual advantage and theories of team reasoning.

The Intergroup Prisoner’s Dilemma with Intragroup Power Dynamics (IPD^2) is a new game paradigm for studying human behavior in conflict situations. IPD^2 adds the concept of intragroup power to an intergroup version of the standard Repeated Prisoner’s Dilemma game. We conducted a laboratory study in which individual human participants played the game against computer strategies of various complexities. The results show that participants tend to cooperate more when they have greater power status within their groups. IPD^2 yields increasing levels of mutual cooperation and decreasing levels of mutual defection, in contrast to a variant of Intergroup Prisoner’s Dilemma without intragroup power dynamics where mutual cooperation and mutual defection are equally likely. We developed a cognitive model of human decision making in this game inspired by the Instance-Based Learning Theory (IBLT) and implemented within the ACT-R cognitive architecture. This model was run in place of a human participant using the same paradigm as the human study. The results from the model show a pattern of behavior similar to that of human data. We conclude with a discussion of the ways in which the IPD^2 paradigm can be applied to studying human behavior in conflict situations. In particular, we present the current study as a possible contribution to corroborating the conjecture that democracy reduces the risk of wars.

This paper provides a new way to identify conditional cooperation in a real-time version of the standard voluntary contribution mechanism. We define contribution cycles as the number of contributors a player waits for before committing to a further contribution, and use a permutation test on contribution cycles to assign a measure of conditional cooperation to each group play. The validity of the measures is tested in an experiment. We find that roughly 20% of the plays exhibit dynamics of conditional cooperation. Moreover, notwithstanding a decline in contributions, conditional cooperation is found to be stable over time.

This paper examines how manager and firm characteristics relate to entry decisions in US local telephone markets. To do so, it develops a structural econometric model that allows managers to be heterogeneous in their ability to correctly conjecture competitor behavior. The model adapts Camerer, Ho, and Chong's (2004) Cognitive Hierarchy model to a real-world setting. We observe the industry in 1998, shortly after the Telecommunications Act of 1996 opened up the market. We find that older firms with older, more experienced managers have higher estimated levels of strategic ability. Managers with degrees in economics or business, and managers with graduate degrees, also have higher estimated levels of strategic ability. We find no evidence that university quality is related to ability. We repeat this exercise using data from 2000, 2002, and 2004. While the core results do not change, the overall level of measured strategic ability increases substantially by 2004. The estimates of strategic ability are also correlated with survival: those firms with lower estimated levels of ability are more likely to exit the industry early.

This article explains the emergence of an unique equilibrium resolution as the result of a compromise between two selves with different preferences. The stronger this difference is, the more generous the resolution gets. This result is in contrast to predictions of other models in which sinful consumption is distributed bimodally. Therefore, our result fits better with our daily observations concerning a lot of ambivalent goods where we often form nonrigid resolutions. The normative analysis uses the device of a hypothetical impartial self that regards both conflicting motives as equally legitimate. The result of this analysis is dilemmatic. It demonstrates that the resolution is broken too often to be welfare maximal. However, the introduction of external self-commitment devices results in their overuse and is welfare decreasing.

Two independent, but related, choice prediction competitions are organized that focus on behavior in simple two-person extensive form games (http://sites.google.com/site/extformpredcomp/): one focuses on predicting the choices of the first mover and the other on predicting the choices of the second mover. The competitions are based on an estimation experiment and a competition experiment. The two experiments use the same methods and subject pool, and examine games randomly selected from the same distribution. The current introductory paper presents the results of the estimation experiment, and clarifies the descriptive value of some baseline models. The best baseline model assumes that each choice is made based on one of several rules. The rules include: rational choice, level-1 reasoning, an attempt to maximize joint payoff, and an attempt to increase fairness. The probability of using the different rules is assumed to be stable over games. The estimated parameters imply that the most popular rule is rational choice; it is used in about half the cases. To participate in the competitions, researchers are asked to email the organizers models (implemented in computer programs) that read the incentive structure as input, and derive the predicted behavior as an output. The submission deadline is 1 December 2011, the results of the competition experiment will not be revealed until that date. The submitted models will be ranked based on their prediction error. The winners of the competitions will be invited to write a paper that describes their model.

We study the perfect Bayesian equilibrium of a model of learning over a general social network. Each individual receives a signal about the underlying state of the world, observes the past actions of a stochastically-generated neighborhood of individuals, and chooses one of two possible actions. The stochastic process generating the neighborhoods defines the network topology (social network). The special case where each individual observes all past actions has been widely studied in the literature. We characterize pure-strategy equilibria for arbitrary stochastic and deterministic social networks and characterize the conditions under which there will be asymptotic learning -- that is, the conditions under which, as the social network becomes large, individuals converge (in probability) to taking the right action. We show that when private beliefs are unbounded (meaning that the implied likelihood ratios are unbounded), there will be asymptotic learning as long as there is some minimal amount of "expansion in observations". Our main theorem shows that when the probability that each individual observes some other individual from the recent past converges to one as the social network becomes large, unbounded private beliefs are sufficient to ensure asymptotic learning. This theorem therefore establishes that, with unbounded private beliefs, there will be asymptotic learning an almost all reasonable social networks. We also show that for most network topologies, when private beliefs are bounded, there will not be asymptotic learning. In addition, in contrast to the special case where all past actions are observed, asymptotic learning is possible even with bounded beliefs in certain stochastic network topologies.

Game-theoretic model of election to a corporate board of directors is proposed. It is shown that the equilibrium distribution of seats is unique. The uniqueness guarantees nonmanipulability of elections. The distribution is obtained by the d’Hondt method of seats distribution in proportional representation problem. The model is tested on real data from a Russian company.

This paper examines a two-period mixed market model in which a welfaremaximizing public firm and a profit-maximizing private firm can use inventory investment as a strategic device. It is then demonstrated that the equilibrium in the second period coincides with the Stackelberg solution where the private firm is the leader, and at equilibrium, both social welfare and the private firm¡¯s profit are higher than in the game without inventory.