|
on Game Theory |
|
Issue of 2011‒10‒01
nineteen papers chosen by Laszlo A. Koczy Hungarian Academy of Sciences and Obuda University |
| By: | Antonio Romero-Medina; Matteo Triossi |
| Abstract: | Studying the interaction between preference and capacity manipulation in matching markets, we prove that acyclicity is a necessary and sufficient condition that guarantees the stability of a Nash equilibrium and the strategy-proofness of truthful capacity revelation under the hospital-optimal and intern-optimal stable rules. We then introduce generalized capacity manipulations games where hospitals move first and state their capacities, and interns are subsequently assigned to hospitals using a sequential mechanism. In this setting, we first consider stable revelation mechanisms and introduce conditions guaranteeing the stability of the outcome. Next, we prove that every stable non-revelation mechanism leads to unstable allocations, unless restrictions on the preferences of the agents are introduced |
| Keywords: | Stable matching, Capacity, Nash equilibrium, Cycles |
| JEL: | C71 C78 D71 D78 |
| Date: | 2011–08 |
| URL: | http://d.repec.org/n?u=RePEc:cte:werepe:we1125&r=gth |
| By: | Oechssler, Jörg |
| Abstract: | 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 (1999) or Bolton and Ockenfels (2000). In fact, repeating the unique stage game equilibrium may not be a subgame perfect equilibrium at all. |
| Keywords: | social preferences; finitely repeated games; inequity aversion; ERC |
| Date: | 2011–09–22 |
| URL: | http://d.repec.org/n?u=RePEc:awi:wpaper:0515&r=gth |
| By: | Abderrahmane ZIAD, University of Caen Basse-Normandie, CREM (UMR CNRS); Samir SBABOU, University of Caen Basse-Normandie, CREM (UMR CNRS); Hatem SMAOUI, CEMOI, Université de la Réunion |
| Abstract: | We define a new class of games, which we qualify as congestion games with exact partition. These games constitute a subfamily of singleton congestion games for which the players are restricted to choose only one strategy, but they each possess their own utility function. The aim of this paper is to develop a method leading to an easier identification of all Nash equilibria in this kind of congestion games. We also give a new proof establishing the existence of a Nash equilibrium in this type of games without invoking the potential function or the finite best-reply property. |
| Keywords: | Singleton congestion games, Nash equilibria, Potential function, Finite best-reply property. |
| JEL: | C72 |
| Date: | 2011–09 |
| URL: | http://d.repec.org/n?u=RePEc:tut:cremwp:201115&r=gth |
| By: | Andersson, Ola (Research Institute of Industrial Economics (IFN)); Wengström, Erik (Lund University) |
| Abstract: | It is well known that communication often serves as a facilitator for cooperation in static games. Yet, communication can serve entirely different purposes in dynamic settings as communication during the game may work as a means for renegotiation, potentially undermining the credibility of cooperative strategies. To explore this issue, this paper experimentally investigates cooperation and non-binding communication in a two-stage game. More specifically, two treatments are considered: one with only pre-play communication and one where subjects can also communicate intra-play between the stages of the game. The results highlight a nontrivial difference concerning the effects of pre-play communication between the two treatments. Pre-play communication only has a significant impact on cooperation when no intra-play communication is possible. The results suggest that the credibility of pre-play messages may depend crucially on future communication opportunities. |
| Keywords: | Communication; Cooperation; Renegotiation; Experiments |
| JEL: | C72 C92 |
| Date: | 2011–09–19 |
| URL: | http://d.repec.org/n?u=RePEc:hhs:iuiwop:0883&r=gth |
| By: | Pablo Brañas-Garza (Universidad de Granada, Spain); Teresa García-Muño (Universidad de Granada, Spain); Roberto Hernán (Economic Science Institute, Chapman University, USA) |
| Abstract: | This paper analyzes cognitive effort in 6 different one-shot p-beauty games. We use both Raven and Cognitive Reflection tests to identify subjects' abilities. We find that the Raven test does not provide any insight on beauty contest game playing but CRT does: subjects with higher scores on this test are more prone to play dominant strategies. |
| Keywords: | Beauty Contest Game, Raven, Cognitive Reflection Test |
| Date: | 2011 |
| URL: | http://d.repec.org/n?u=RePEc:chu:wpaper:11-08&r=gth |
| By: | Abderrahmane ZIAD, University of Caen Basse-Normandie, CREM (UMR CNRS); Samir SBABOU, University of Caen Basse-Normandie, CREM (UMR CNRS); Hatem SMAOUI, CEMOI, Université de la Réunion |
| Abstract: | In this note we study the existence of Nash equilibria in nonsymmetric finite congestion games, complementing the results obtained by Milchtaich on monotone-decreasing congestion games. More specifically, we examine the case of two resources and we propose a simple method describing all Nash equilibria in this kind of congestion games. Additionally, we give a new and short proof establishing the existence of a Nash equilibrium in this type of games without invoking the potential function or the finite improvement property. |
| Keywords: | Singleton congestion games, Nash equilibria, Potential function, Finite improvement property |
| JEL: | C72 |
| Date: | 2011–09 |
| URL: | http://d.repec.org/n?u=RePEc:tut:cremwp:201113&r=gth |
| By: | Dreber, Anna (Dept. of Economics, Stockholm School of Economics); Ellingsen, Tore (Dept. of Economics, Stockholm School of Economics); Johannesson, Magnus (Dept. of Economics, Stockholm School of Economics); Rand, David (Harvard University) |
| Abstract: | Many previous experiments document that behavior in multi-person settings responds to the name of the game and the labeling of strategies. Usually these studies cannot tell whether frames affect preferences or beliefs. In this Dictator game study, we investigate whether social framing effects are also present when only one of the subjects makes a decision, in which case the frame may only affect preferences. We find that behavior is insensitive to social framing. |
| Keywords: | beliefs; preferences; framing effects; altruism; cooperation |
| JEL: | C70 C91 D64 |
| Date: | 2011–09–14 |
| URL: | http://d.repec.org/n?u=RePEc:hhs:hastef:0738&r=gth |
| By: | Abderrahmane ZIAD, University of Caen Basse-Normandie, CREM (UMR CNRS); Samir SBABOU, University of Caen Basse-Normandie, CREM (UMR CNRS); Hatem SMAOUI, CEMOI, Université de la Réunion |
| Abstract: | This paper provides a simple formula describing all Nash equilibria in symmetric monotone singleton congestion games. Our approach also yields a new and short proof establishing the existence of a Nash equilibrium in this kind of congestion games without invoking the potential function or the nite improvement property. |
| Keywords: | Singleton congestion games, Nash equilibria, Potential function, Finite improvement property |
| JEL: | C72 |
| Date: | 2011–09 |
| URL: | http://d.repec.org/n?u=RePEc:tut:cremwp:201114&r=gth |
| By: | Breitmoser, Yves; Tan, Jonathan H.W. |
| Abstract: | We show and explain how generosity beyond that explainable by social preferences can manifest in bargaining. We analyze an ultimata game with two parties vying to coalesce with a randomly chosen proposer. They simultaneously demand shares of the surplus. The proposer must then make an offer that meets at least one demand, or else the game either continues with a new round or breaks down with all earning zero. Self-interest, altruism, and inequity aversion univocally predict miniscule demands due to inter-party competition; proposers thus obtain the lion's share. We experimentally observe that proposers coalesce with the less demanding party by strategically matching demands, like ultimatum bargaining, but also give non-strategically to the other party, like dictator giving. The observations are incompatible with concave utilities, as implied by social preferences, but are compatible with reference dependent preferences. |
| Keywords: | demand commitment; ultimata bargaining; non-cooperative; laboratory experiment; social preferences; reference dependence |
| JEL: | C78 D72 C72 C91 |
| Date: | 2011–09–22 |
| URL: | http://d.repec.org/n?u=RePEc:pra:mprapa:33613&r=gth |
| By: | Michel Grabisch (CES - Centre d'économie de la Sorbonne - CNRS : UMR8174 - Université Panthéon-Sorbonne - Paris I); Tong Li (Beijing Institute of Technology - Beijing Institute of Technology) |
| Abstract: | An extension to the classical notion of core is the notion of $k$-additive core, that is, the set of $k$-additive games which dominate a given game, where a $k$-additive game has its Möbius transform (or Harsanyi dividends) vanishing for subsets of more than $k$ elements. Therefore, the 1-additive core coincides with the classical core. The advantages of the $k$-additive core is that it is never empty once $k\geq 2$, and that it preserves the idea of coalitional rationality. However, it produces $k$-imputations, that is, imputations on individuals and coalitions of at most $k$ individuals, instead of a classical imputation. Therefore one needs to derive a classical imputation from a $k$-order imputation by a so-called sharing rule. The paper investigates what set of imputations the $k$-additive core can produce from a given sharing rule. |
| Date: | 2011 |
| URL: | http://d.repec.org/n?u=RePEc:hal:cesptp:hal-00625339&r=gth |
| By: | Müller, Julia; Schwieren, Christiane |
| Abstract: | The beauty contest game has been used to analyze how many steps of reasoning subjects are able to perform. A common finding is that a majority seem to have low levels of reasoning. We use eye-tracking to investigate not only the number chosen in the game, but also the strategies in use and the numbers contemplated. We can show that not all cases that are seemingly level-1 or level-2 thinking indeed are {they might be highly sophisticated adaptations to beliefs about other people's limited reasoning abilities. |
| Keywords: | beauty contest game; levels of reasoning; level-k model; strategic reason ing; cognitive hierarchy |
| Date: | 2011–09–22 |
| URL: | http://d.repec.org/n?u=RePEc:awi:wpaper:0516&r=gth |
| By: | Chetan Dave; Stefan Dodds; Sheryl Ball; Rachel Croson |
| Abstract: | A foundational paradox in social choice theory is that liberalism (freedom of action) and Pareto efficiency, the standard in evaluating economic outcomes, can conflict with each other (Sen 1970). We capture this tension in a series of sequential Battle of the Sexes game experiments. We find that most individuals are willing to waive rights to achieve efficient outcomes. In addition efficiency is higher when participants may claim new rights than when they may relinquish them or when only one player possesses them. This evidence may help resolve the tensions between efficiency and liberty that lie at the heart of social choice and political philosophy. |
| Keywords: | Pareto Optimality, Sen’s Paradox, Social Choice, Minimal Liberalism, preferences, rights, Battle of the Sexes game  |
| Date: | 2011 |
| URL: | http://d.repec.org/n?u=RePEc:vpi:wpaper:e07-30&r=gth |
| By: | Antonio Romero-Medina; Matteo Triossi |
| Abstract: | This paper analyzes the role of acyclicity in singleton cores. We show that the absence of simultaneous cycles is a sufficient condition for the existence of singleton cores. Furthermore, acyclicity in the preferences of either side of the market is a minimal condition that guarantees the existence of singleton cores. If firms or workers preferences are acyclical, unique stable matching is obtained through a procedure that resembles a serial dictatorship. Thus, acyclicity generalizes the notion of common preferences. It follows that if the firms or workers preferences are acyclical, unique stable matching is strongly efficient for the other side of the market |
| Keywords: | Stable matching, Acyclicity, Singleton cores |
| JEL: | C71 C78 D71 |
| Date: | 2011–08 |
| URL: | http://d.repec.org/n?u=RePEc:cte:werepe:we1126&r=gth |
| By: | Abderrahmane ZIAD, University of Caen Basse-Normandie, CREM (UMR CNRS); Emmanuelle TAUGOURDEAU, CNRS CES, Université de Paris 1, ENS Cachan |
| Abstract: | This paper studies the existence of a fiscal Nash equilibrium in a multi-country model of trade where the relative prices are the channels of transmission of scal policies between countries. We stipulate the necessary conditions on goods, consumptions and trade that allow for the existence of a Nash equilibrium in the fiscal game. In the particular case of homotethic utility functions, we show that conditions on the shape and the degree of the curvature of the relative prices functions are sufficient to guarantee the existence of the Nash equilibrium. |
| Keywords: | Fiscal policy, Trade, Nash equilibrium. |
| JEL: | C62 C72 F42 |
| Date: | 2011–09 |
| URL: | http://d.repec.org/n?u=RePEc:tut:cremwp:201112&r=gth |
| By: | Fabien MOIZEAU, University of Rennes 1 - CREM-CNRS; Fernando JARAMILLO, Universidad del Rosario, Bogota (Colombia); Hubert KEMPF, École Normale Supérieure de Cachan et Paris School of Economics |
| Abstract: | We study the relationship between the distribution of individuals' attributes over the population and the extent of risk sharing in a risky environment. We consider a society where individuals differing with respect to risk or their degree of risk aversion form risk-sharing coalitions in the absence of financial markets. We obtain a partition belonging to the core of the membership game. It is homophily-based: the less risky (or the more risk tolerant) agents congregate together and reject more risky ones (or less risk tolerant ones) into other coalitions. The distribution of risk or risk aversion affects the number and the size of these coalitions. It turns out that individuals may pay a lower risk premium in more risky societies. We also show that a higher heterogeneity in risk or risk aversion leads to a lower degree of partial risk-sharing. The empirical evidence on partial risk sharing can be understood when the endogenous partition of society into risk-sharing coalitions is taken into account. |
| Keywords: | Risk Sharing, Group Membership, Social Segmentation |
| JEL: | C71 D3 D71 D81 |
| Date: | 2011–09 |
| URL: | http://d.repec.org/n?u=RePEc:tut:cremwp:201111&r=gth |
| By: | Fabien Lange (Keleti Faculty of Economics - Budapest Tech); Michel Grabisch (CES - Centre d'économie de la Sorbonne - CNRS : UMR8174 - Université Panthéon-Sorbonne - Paris I) |
| Abstract: | Bi-capacities are a natural generalization of capacities (or fuzzy measures) in a context of decision making where underlying scales are bipolar. They are able to capture a wide variety of decision behaviours. After a short presentation of the basis structure, we introduce the Shapley value and the interaction index for capacities. Afterwards, the case of bi-capacities is studied with new axiomatizations of the interaction index. |
| Date: | 2011 |
| URL: | http://d.repec.org/n?u=RePEc:hal:cesptp:hal-00625355&r=gth |
| By: | Juliette Rouchier (GREQAM - Groupement de Recherche en Économie Quantitative d'Aix-Marseille - Université de la Méditerranée - Aix-Marseille II - Université Paul Cézanne - Aix-Marseille III - Ecole des Hautes Etudes en Sciences Sociales (EHESS) - CNRS : UMR6579); Emily Tanimura (GREQAM - Groupement de Recherche en Économie Quantitative d'Aix-Marseille - Université de la Méditerranée - Aix-Marseille II - Université Paul Cézanne - Aix-Marseille III - Ecole des Hautes Etudes en Sciences Sociales (EHESS) - CNRS : UMR6579, CES - Centre d'économie de la Sorbonne - CNRS : UMR8174 - Université Panthéon-Sorbonne - Paris I) |
| Abstract: | This paper presents a model of influence where agents' beliefs are based on an objective reality, such as the properties of an environment. The perception of the objective reality is not direct: all agents know is that the more correct a belief, the more successful the actions that are deduced from this belief. (A pair of agents can influence each other when )Agents can influence eachother by pair when they perform a joint action. They are not only defined by individual beliefs, but also idyosynchratic confidence in their belief - this means that they are not all willing to (engage in action with) act with agents with a different belief and to be influenced by them. We show here that the distribution of confidence in the group has a huge impact on the speed and quality of collective learning and in particular that a small number of overconfident agents can prevent the whole group frow learning properly. |
| Date: | 2011–07–06 |
| URL: | http://d.repec.org/n?u=RePEc:hal:cesptp:hal-00623966&r=gth |
| By: | Eva-Maria Steiger (Max Planck Institute of Economics, Jena); Ro'i Zultan |
| Abstract: | Transparency in teams can induce cooperation. We study contribution decisions by agents when previous decisions can be observed. We find that an information chain, in which each agent directly observes only the decision of her immediate predecessor, is at least as effective as a fully-transparent protocol in inducing cooperation under increasing returns to scale. In a comparable social dilemma, the information chain leads to high cooperation both when compared to a non-transparent protocol for early movers, and when compared to a fully-transparent protocol for late movers. we conclude that information chains facilitate cooperation by balancing positive and negative reciprocity. |
| Keywords: | team production, public goods, incentives, externality, information, transparency, conditional cooperation |
| JEL: | C72 C92 D21 J31 M52 |
| Date: | 2011–09–23 |
| URL: | http://d.repec.org/n?u=RePEc:jrp:jrpwrp:2011-040&r=gth |
| By: | Andersson, Christer (Lund University); Andersson, Ola (Research Institute of Industrial Economics (IFN)); Andersson, Tommy (Lund University) |
| Abstract: | This paper considers the sealed bid and ascending auction, which both identifies the minimum Walrasian equilibrium prices and where truthful preference revelation constitutes an equilibrium. Even though these auction formats share many theortical properties, there are behavioral aspects that are not easily captured. To explore this issue in more detail, this paper experimentally investigates what role the design of the auction format has for its outcome. The results suggest that the sealed bid mechanism performs weakly better in all of investigated measures (consistent reporting, efficiency etc.). In addition, we find that the performance of the ascending auction is increasing over time, whereas the sealed bid auction shows no such tendency. |
| Keywords: | Auctions; Non-manipulability; Efficiency; Experiments |
| JEL: | C91 D44 |
| Date: | 2011–09–19 |
| URL: | http://d.repec.org/n?u=RePEc:hhs:iuiwop:0882&r=gth |