Culture sometimes matters: Intra-cultural variation in pro-social behavior among Tsimane Amerindians

Agent-centered models usually consider only individual-level variables in calculations of economic costs and benefits. There has been little consideration of social or cultural history on shaping payoffs in ways that impact decisions. To examine the role of local expectations on economic behavior, we explore whether village affiliation accounts for the variation in dictator game offers among the Tsimane of the Bolivian Amazon independently of other factors that could confound such an effect. Our analysis shows that significant differences in altruistic giving exist among villages, village patterns are recognized by residents, and offers likely reflect variation in social expectations rather than stable differences in norms of fairness.     

Expectations, Drift, and Volatility in Evolutionary Games

This paper proposes an evolutionary model of learning in simple coordination games where expectations are the driving force of the process. As time proceeds, agents adjust their expectations through some (possibly different) updating rules, whose only requirement is that of consistency with long stationary evidence. Sporadically, expectations are also subject to arbitrary perturbation. The main point of the paper is that, due to the possibility of random drift on expectations, the evolutionary process will be subject to high volatility across equilibria. Specifically, every Nash equilibrium (even if risk- or payoff-dominated) will have significant positive weight in the long-run invariant distribution. Journal of Economic Literature Classification Numbers: C73. D83. D84.     

Buyer behavior under the Best Offer mechanism: A theoretical model and empirical evidence from eBay Motors

We use data from eBay Best Offer listings to analyze haggling over prices in transactions with one seller and a series of potential buyers for a limited-supply product. We characterize this transaction mechanism as a sequential-move game to investigate buyer behavior. Our model suggests that a buyer's offer price increases in relations to the number of buyers who have previously made an offer on the item and the Buy-It-Now price chosen by the seller. On the other hand, the offer price decreases for items which have been listed on eBay for a longer period of time. We empirically test our theoretical predictions using data on the sales of Toyota Camry cars on eBay Motors. The empirical evidence is consistent with our model.     

More Is Better, But Fair Is Fair: Tipping in Dictator and Ultimatum Games

This paper examines Allocators' willingness to reward and punish their paired Recipients. Recipients only compete in a skill-testing contest, the outcome of which determines the size of the surplus. In the dictator game, Allocators reward skillful Recipients, but punish unskillful ones only modestly. The punishment effect is mitigated by the belief held by some Allocators thateffortis the appropriate measure of deservingness. The ultimatum game extension reveals offerers' ability to adapt to the strategic environment. Offers to skillful Recipients in the ultimatum game, however, are shown to be motivated by a taste for fairness, and not strategic considerations.Journal of Economic LiteratureClassification Numbers: C70, C91, D63.     

Exchange Rates,Expectations, and Monetary Policy: a NOEM Perspective*

We use a dynamic general‐equilibrium optimizing two‐country model to analyze how the formation of exchange rate expectations shapes the effects of a monetary policy shock in an open economy. We also provide empirical evidence on how traders in foreign exchange markets form exchange rate expectations. Our model implies that the short‐run output effect of a permanent monetary policy shock diminishes if “technical traders” form the type of regressive exchange rate expectations we find in our empirical analysis. If the influence of technical traders is strong enough, a permanent expansionary monetary policy shock can result in a temporary decline of the output in the country in which it takes place. The output effect of a temporary monetary policy shock is magnified when technical traders form regressive exchange rate expectations.     

Information at equilibrium

Summary. In a game with rational expectations, individuals simultaneously refine their information with the information revealed by the strategies of other individuals. At a Nash equilibrium of a game with rational expectations, the information of individuals is essentially symmetric: the same profile of strategies is also an equilibrium of a game with symmetric information; and strategies are common knowledge. If each player has a veto act, which yields a minimum payoff that no other profile of strategies attains, then the veto profile is the only Nash equilibrium, and it is is an equilibrium with rational expectations and essentially symmetric information; which accounts for the impossibility of speculation. Received: June 20, 2001; revised version: January 9, 2002 RID="*" ID="*" We wish to thank Pierpaolo Battigalli, Fran?oise Forges, Franco Donzelli, Leonidas Koutsougeras, Aldo Rustichini, Rajiv Vohra and Nicholas Yannelis for their comments. Correspondence to: H. Polemarchakis     

Testing subgame perfection apart from fairness in ultimatum games

We present an experiment designed to separate the two commonplace explanations for behavior in ultimatum games—subjects’ concern for fairness versus the failure of subgame perfection as an equilibrium refinement. We employ a tournament structure of the bargaining interaction to eliminate the potential for fairness to influence behavior. Comparing the results of the tournament game with two control treatments affords us a clean test of subgame perfection as well as a measure fairness-induced play. We find after 10 iterations of play that about half of all non-subgame-perfect demands are due to fairness, and the rest to imperfect learning. However, as suggested by models of learning, we also confirm that the ultimatum game presents an especially difficult environment for learning subgame perfection. Electronic Supplementary Material Supplementary material is available in the online version of this article at . JEL Classification C91, D64, J52     

Revisiting strategic versus non-strategic cooperation

We propose a novel experimental method that disentangles strategically- and non-strategically-motivated behavior. We apply it to an indefinitely-repeated prisoner’s dilemma game to observe simultaneously how the same individual behaves in situations with future interaction and in situations with no future interaction, while controlling for expectations. This method allows us to determine the extent to which strategically-cooperating individuals are responsible for the observed pattern of cooperation in experiments with repeated interaction, including the so-called endgame effect. Our results indicate that the most common motive for cooperation in repeated games is strategic.     

Speculative and hedging interaction model in oil and U.S. dollar markets with financial transaction taxes

Our article develops a game theory model of interaction between speculative and hedging behaviors in the oil and US dollar markets, in the presence of a severe taxation on speculative financial transactions. From this microeconomic analysis, we derive a regulatory policy. This policy has two consequences at the macro level: on one hand, it has a certain stabilizing effects on oil and US dollar markets, limiting the number of speculative transactions and their size; on the other hand, it induces the speculators to find agreements with real economic agents, which are profitable for both parts. Moreover, we propose that the tax is mostly re-directed to support the real economy. So, the aim of this paper appears twofold: by using Game Theory, we suggest to a pair of economic agents a way to gain in a market, also in presence of a hard taxation on the financial transactions, proposing, at the same time, to normative authority, a method to limit the instability of oil and U.S. Dollar markets and to help real economy. Our idea, at the micro-economic level, is to exploit the hedging actions to obtain a profit, limiting, at the same time, at a macro-level, the speculative attacks on oil and U.S. Dollar markets. These goals are reached by the introduction of well designed financial transactions tax. In particular, we focus on a real economic subject (Multinational Air) and on an investment bank (Bank). The solutions collectively efficient are determined, at a micro-level, by certain agreements between the two economic subjects. Specifically, after an agreement which allows to obtain the maximum collective profit of the interaction, we propose and analyze four different possible fair divisions of this gain, by adopting the Kalai–Smorodinsky method.     

农产品交易行为的动态演化博弈分析

本文基于演化博弈理论,针对交易双方的有限理性,建立了一个引入博弈参与人学习调整的农产品买卖交易模型,分析了个体策略选择机制在模型中的动态演化过程,得出了博弈参与人通过不断的学习调整,最终形成"强-弱"或"弱-强"要价策略组合的稳定均衡结果的结论。在此基础上,进一步探讨了买卖双方偏离独立的个人价值差异区间中心点的程度对演化稳定均衡解的影响。     

A Bargaining Experiment to Motivate Discussion on Fairness

The author presents a classroom version of the popular research game called the Ultimatum Game. Researchers are placing growing importance on how fairness affects behavior, and this experiment provides a useful, fun, and engaging way in which a day or two of class time can be spent on the topic. The appendix contains all of the materials necessary to conduct this experiment, and the experiment can highlight several items of interest for the instructor. First, different individuals place different subjective weights on concerns for fairness versus money. Second, theories that incorporate concerns for fairness into agents' preferences can often explain behavior better than those that do not. Finally, when it is relatively cheap to purchase fairness (or equality) individuals purchase more of it. The classroom results can motivate discussion of a downward sloping demand curve for fairness.     

Tax evasion and social interactions

The paper extends the standard tax evasion model by allowing for social interactions. In Manski's [Manski, C.F. (1993). Identification of Endogenous Social Effects: The Reflection Problem. Review of Economic Studies 60(3), 531–542.] nomenclature, our model takes into account endogenous interactions, i.e., social conformity effects, exogenous interactions, i.e., fairness effects, and correlated effects. Our model is tested using experimental data. Participants must decide how much income to report given individual and group tax rates and audit probabilities, and given a feedback on the other members' reporting behavior. Myopic and self-consistent expectations are considered in the analysis. In the latter case, the estimation is based on a two-limit simultaneous tobit with fixed group effects. A unique social equilibrium exists when the model satisfies coherency conditions. In line with Brock and Durlauf [Brock, W.A., Durlauf, S.N. (2001b). Interactions-Based Models, in J. Heckman and E. Leamer, eds., Handbook of Econometrics 5, Elsevier Science B.V., 3297–380.], the intrinsic nonlinearity between individual and group responses helps identify the model. Our results provide evidence of fairness effects but reject social conformity.     

A stress test of fairness measures in models of social utility

Summary. Current social utility models posit fairness as a motive for certain types of strategic behavior. The models differ, however, with respect to how fairness is measured. Distribution models measure fairness in terms of relative payoff comparisons. Reciprocal-kindness models measure fairness in terms of gifts given and gifts received. Reference points play an important role in both measures, but the reference points in reciprocal-kindness models are conditioned on the actions available to players, whereas those in distributive models are not. Data from an ultimatum game experiment that stress tests the kindness measure is consistent with the distributive measure. Data from an experiment that stress tests the distributive measure is inconsistent with the distributive measure, but moves in the direction opposite that implied by the kindness measure. A measure that combines relative payoff comparisons with a reference point conditioned on feasible actions provides a first approximation to our data.Received: 12 August 2002, Revised: 27 November 2003, JEL Classification Numbers: C78, C91, D63. Correspondence to: Axel OckenfelsBolton gratefully acknowledges the support of the National Science Foundation. Ockenfels thanks Alvin Roth and the Harvard Business School for their generous hospitality, and the Deutsche Forschungsgemeinschaft for their support through the Emmy Noether-program. Both authors gratefully acknowledge the hospitality of the Making Choices project at the Center for Interdisciplinary Research, University of Bielefeld during the summer of 2000. We also thank an anonymous referee and seminar participants in Bielefeld, Boston, Columbus, Harvard, and Jena for helpful comments.     

The ERM Effect,Conflict and Inflation in the European Union

This paper investigates price inflation expectations and wage determination in the ERM member countries with the aim of assessing the importance of the ERM effect and distributional conflict. We have found strong evidence of an ERM effect in the inflationary process of participating countries, but this effect manifests itself primarily through structural changes in labour markets rather than through importing Bundesbank's reputation. This evidence questions the tendency to model the ERM as a credibility-reputation game. Inflation expectations for all ERM countries are strongly influenced by movements in unit labour costs and demand, and secondarily by world commodity and oil prices. The empirical results provide strong support for the conflict approach to wage inflation.     

VIDEO GAMES AND CRIME

Psychological studies find that video game play is associated with markers for violent and antisocial attitudes. It is plausible that these markers indicate either whetted or sated preferences for antisocial behavior. I investigate whether a proxy for video gaming is associated with the prevalence of various crimes and find evidence that gaming is associated with significant declines in crime and death rates. These results are robust to various alternative specifications. Other youth‐related leisure activities—sports and movie viewing—generate smaller or no effects. These results cast doubt on the desirability of proposed restrictions on video game marketing. (JEL L86, D18, I18)     

Fairness, errors and the power of competition

In this paper, we investigate the effects of competition on bargained outcomes. We show that the neglect of either fairness concerns or decision errors will prevent a satisfactory understanding of how competition affects bargaining. We conducted experiments which demonstrate that introducing a small amount of competition to a bilateral ultimatum game – by adding just one competitor – induces large behavioral changes among responders and proposers, causing large changes in accepted offers. Models that assume that all people are self-interested and fully rational do not adequately explain these changes. We show that a model which combines heterogeneous fairness concerns with decision errors correctly predicts the comparative static effects of changes in competition. Moreover, the combined model is remarkably good at predicting the entire distribution of offers in many different competitive situations.     

Rationalizability, Strong Rationality, and Expectational Stability

We examine the connection between two stability concepts of rational expectations equilibria: expectational stability, based on the convergence of iterations of expectations, and strong rationality, based on uniqueness of the rationalizable solutions of an associated game with restrictions on beliefs. To compare the concepts we embed a standard expectations model in a game-theoretic framework. It is shown that the two stability concepts coincide when agents are homogeneous. For the general case of heterogeneous agents we show that expectational stability is a necessary condition for strong rationality and we provide a sufficient condition for the latter. Journal of Economic Literature Classification Numbers: C72, C62.     

DO WEALTH DIFFERENCES AFFECT FAIRNESS CONSIDERATIONS?*

The influence of relative wealth on fairness considerations is analyzed in an ultimatum game experiment in which participants receive large and widely unequal initial endowments. Subjects initially demonstrate a concern for fairness. With time however, behavior becomes at odds with both subgame perfection and fairness. Evidence of learning is detected for both proposers and receivers in the estimation of a structural reinforcement learning model. The estimation results suggest that, guided by foregone best responses and an acquired sense of deservingness, rich subjects become more selfish, whereas poor subjects, influenced only by their own experience, learn to tolerate this behavior.     

A simple model for study of the determination of the price level and the interaction of monetary and fiscal policy

Summary A representative-agent model with money holdings motivated by transactions costs, a fiscal authority that taxes and issues debt, no production, and a convenient functional form for agents' utility is presented. The model can be solved analytically, and illustrates the dependence of price determination on fiscal policy, the possibility of indeterminacy, even stochastic explosion, of the price level in the face of a monetary policy that holdsM fixed, and the possibility of a unique, stable price level in the face of a monetary policy that simply pegs the nominal interest rate at an arbitrary level.In a rational expectations, market-clearing equilibrium model with a costlessly-produced fiat money that is useful in transactions, the following things are true under broad assumptions.- A monetary policy that fixes the money stock may (depending on the transactions technology) be consistent with indeterminacy of the price level—indeed with stochastically fluctuating, explosive inflation.- A monetary policy that fixes the nominal interest rate, even if it holds the interest rate constant regardless of the observed rate of inflation or money growth rate, may deliver a uniquely determined price level.- The existence and uniqueness of the equilibrium price level cannot be determined from knowledge of monetary policy alone; fiscal policy plays an equally important role. Special case models with interest-bearing debt and no money are possible, just as are special cases with money and no interest-bearing debt. In each the price level may be uniquely determined.Determinacy of the price level under any policy depends on the public's beliefs about what the policy authority would do under conditions that are never observed in equilibrium.These points are not new. Eric Leeper [1991] has made most of them within a single coherent model. Woodford [1993], in a representative agent cash-in-advance model, has displayed the possibility of indeterminacy with a fixed quantity of money and the possibility of uniqueness with an interest-rate pegging policy. Aiyagari and Gertler [1985] use an overlapping generations model to make many of the points made in this paper, without discussing the possibility of stochastic sunspot equilibria. Sargent and Wallace [1981] and Obstfeld [1983] have also discussed related issues.This paper improves on Leeper by moving beyond his analysis of local linear approximations to the full model solution, as is essential if explosive sunspot equilibria are to be distinguished from explosive solutions to the Euler equations that can be ruled out as equilibria. It improves on the other cited work by pulling together into the context of one fairly transparent model discussion of phenomena previously discussed in isolation in very different models.We study a representative agent model in which there is no production or real savings, but transactions costs generate a demand for money. The government costlessly provides fiat money balances, imposes lump-sum taxes, and issues debt, but has no other role in the economy. We make restrictive assumptions about the form of the utility function and the form of a transactions cost term in the budget constraint.The model could be extended to include production, capital accumulation, non-neutral taxation, productive government expenditure, and a more general utility function without affecting the conclusions discussed in this paper. Indeed the model I informally matched to data in an earlier paper [1988] makes some such extensions. While such an extended model is more realistic, it is harder to solve. The version in my earlier paper [1988] was solved numerically and simulated. The bare-bones model of this paper allows an explicit analytic solution that may make its results easier to understand.This paper improved following comments from participants at seminars at Yale and the Atlanta Federal Reserve Bank. Eric Leeper and James Robinson were particularly helpful. Comments from Michael Woodford led to important corrections and clarifications.     

A test of the rational expectations hypothesis using data from a natural experiment

Data on contestants’ choices in Italian Game Show Affari Tuoi are analysed in a way that separates the effect of risk attitude (preferences) from that of beliefs concerning the amount of money that will be offered to contestants in future rounds. This separate identification is possible by virtue of the fact that, at a certain stage of the game, beliefs are not relevant, and risk attitude is the sole determinant of choice. The rational expectations hypothesis is tested by comparing the estimated belief function with the ‘true’ offer function which is estimated extraneously using data on offers actually made to contestants. We find a close correspondence, leading us to accept the rational expectations hypothesis. The importance of belief formation is confirmed by the estimation of a mixture model which establishes that the vast majority of contestants are forward looking as opposed to myopic.