learning to believe in sunspots a number of authors have shown that competitive economies may possess sunspot equilibria that is rational expectations equilibria in which purely extrinsic uncertainty affects equilibrium prices and allocations 2 such results demonstrate that it does not require a lack of faith in the rationality of market participants to believe that competitive markets may be subject to purely speculative fluctuations driven solely by expectations 3 the mere existence of sunspot equilibria as solutions to a system of marketclearing conditions however might not be judged sufficient to indicate that competitive markets with rational participants could ever be subject to speculative instability the sunspot equilibria represent states of affairs in which agents act differently in the case of different realizations of the sunspot variable and it is rational for each agent to do so but it might be thought unlikely that the beliefs of all the participants in the market could ever come to be coordinated so as to bring about an equilibrium of that kind it is rational to believe that sunspots convey information about future states of affairs once the economy is in a sunspot equilibrium but why would rational agents ever begin to believe in such a thing so as to create the conditions under which the belief is rational in order to address such a question one must go beyond the mere statement of the conditions for equilibrium and discussion of what states of affairs satisfy them one must specify an explicit dynamic process according to which the beliefs of agents adjust when out of equilibrium any exercise of this kind is necessarily unsatisfactory as there is no univocal meaning for the postulate of rational behavior outside of an equilibrium it may well be the case that

sequential bargaining as a noncooperative foundation for walrasian equilibrium allocation are weakly preferred to those obtainable from the initial endowments by means of the given set of net trades these conditions are similar to ones studied by schmeidler and vind 1972 and vind 1978 but here they are thought of as characterizing the set of net trades available in steady state equilibria of market games like those studied by douglas gale 1984 1985 1986a 1986b and 1986c the characterization result is used as a key step in the proof of results like gale s the allocations induced by steady state equilibria are walrasian for the economy given by the constant flow of new agents into the market our approach generalizes the one followed in gale 1986c and allows us to dispense with assumptions made in previous treatments for example gale s 1986a assumption of dispersed characteristics is dropped we also demonstrate that such a result depends on the assumption that agents cannot observe the past behavior of agents with whom they trade

expectationally driven market volatility an experimental study abstract we study the existence and robustness of expectationally driven price volatility in experimental overlapping generation economies in the theoretical model under study there exist pure sunspot equilibria which can be learned if agents use some adaptive learning rules our data show the existence of expectationally driven cycles but only after subjects have been exposed to a sequence of real shocks and learned a real cycle in this sense we show evidence of path dependent price volatility journal of economic literature classification numbers c62 c92 f17 e32 e44

equilibrium selection in an experimental macroeconomy author affiliation vivian lei department of economics university of wisconsin milwaukee milwaukee wi 53201 usa vlei uwm edu corresponding authorcharles n noussair department of economics faculty of economics and business tilburg university p o box 90153 5000 le tilburg the netherlands c n noussair uvt nl acknowledgment we are grateful to the college of letters and science and center for research on international economics at the university of wisconsin milwaukee for financial support we thank colin camerer katarina kellar lutz hendricks nazrul islam tomomi tanaka filip vesely and two anonymous referees for helpful comments 1 introductionone of the most influential literatures in economics is the theory of growth for surveys see azariadis 1993 barro and sala i martin 1995 romer 1996 sala i martin 2002 the basis of much of the literature is the ramsey 1928 cass 1965 koopmans 1965 growth model in this model the economy is assumed to behave like a benevolent social planner who chooses capital stock and consumption levels over an infinite time horizon with the goal of maximizing the discounted utility of the consumption stream the principal result of the model is that consumption and capital stock converge to unique optimal steady state levels that are independent of the initial endowment and the utility function of the social planner an implication of the model therefore is that different countries would converge toward a common income level even if their initial endowment of capital differed provided that they have access to the same production technology relatively poor countries would exhibit higher growth rates than richer ones these two predictions are testable with field data however field studies have generally failed to support the hypothesis of convergence toward a common income level see durlauf and quah 1999 temple 1999 and islam 2003 for surveys rather the data are more consistent with the alternative hypothesis of club convergence baumol 1986 which postulates that a small number of steady states exist and that each country has a tendency to converge toward one of them 1 such a framework can explain the observed pattern over time of an increase in income differences between the organisation for economic cooperation and development countries and the developing world as well as a decrease in the differences within each of the two groups the empirical support for club convergence has encouraged the development of theoretical models with multiple equilibria while some countries may reach optimal equilibria unfortunate countries might find themselves in low income equilibria which are often labeled as poverty traps these countries are unable to reach a better equilibrium without coordination originally due to rosenstein rodan 1943 the insight that the existence of multiple equilibria might provide an explanation of international income differences has led to a literature that considers a variety of growth models with multiple equilibria for example azariadis and drazen 1990 construct an overlapping generations model with two stable pareto rankable equilibria in the inferior equilibrium no agent trades with members of other generations murphy shleifer and vishny 1989 build a model with synergies between industries each industry is profitable only if other industries are operating and there are equilibria where all of the industries operate and other pareto dominated equilibria where none operate galor and zeira 1993 and banerjee et al 2001 show that inequality and differential access to credit can keep an economy in a pareto dominated equilibrium recognizing whether or not an economy has multiple equilibria is important because policy prescriptions differ depending on whether an economy is in an inferior equilibrium or whether it is in an equilibrium that is unique

limit theorems for markets with sequential bargaining this paper models trade as a non coopertative strategic game played at an inlinite sequence of dates a single indivisible commodity is traded buyers and sellers have transferable utility and are characterized by their reservation utilities they meet at random and bargain over the price at which a single unit of the good will be exchanged under a variety of circumstances it is shown that as the costs of search and bargaining become negligible the outcome of the game converges to the competitve flow equilibrium even when there is complete information journal of economic literature classification numbers 022 19x7

decentralized trading strategic behaviour and the walrasian outcome for a market with a finite number of agents pairwise matching and bargaining it is shown that even when the market is frictionless the equilibrium is not necessarily competitive it depends on the amount of information agents use if their behaviour is conditioned only on the sets of agents present and the time the competitive solution is the unique subgame perfect equilibrium if agents have full information and condition their behaviour on some of it there are also noncompetitive equilibria in which behaviour depends on specific information such as the identity of the trading partner and past events

auctions actions and the failure of information aggregation we study a market where k identical and indivisible objects are allocated using a uniform price auction where n k bidders each demand one object before the auction each bidder receives an informative but imperfect signal about the state of the world the good that is auctioned is a common value object for the bidders and a bidder s valuation for the object is determined jointly by the state of the world and an action that he chooses after winning the object but before he observes the state we show that there are equilibria where the auction price is completely uninformative about the state of the world and aggregates no information even in an arbitrarily large auction in the equilibrium that we construct because prices do not aggregate information agents have strict incentives to acquire costly information before they participate in the market also market statistics other than price such as the amount of rationing and bid distributions contain extra information about the state our findings sharply contrast with past work which shows that large auctions aggregate information when there is no ex post action

screening in a matching market contract design under incomplete information is often analysed in a bilaterally monopolistic setting if the informed party s reservation value does not depend on its private information its type it is a standard result that the uninformed side offers low types distorted contracts to reduce the information rent left to high types we challenge this result by embedding contract design in a matching market environment we consider a market where players meet pairwise and where in each match either side may be chosen to make a take it or leave it offer as frictions become sufficiently low we find that the set of equilibria is independent of whether there is complete or incomplete information in particular all contracts are free of distortions

a strategy experiment in dynamic asset pricing this study presents a strategy experiment in a simple dynamic asset pricing model where the current market equilibrium asset price is determined by aggregated individual expectations of next period s price after participating in an introductory laboratory experiment on expectation formation participants formulate a complete forecasting strategy these strategies are programmed and markets are simulated participants receive feedback from the results of these simulations and can adapt their strategy four rounds are played and the entire experiment lasts eight weeks a final laboratory experiment compares predictions of participants with the predictions of the submitted strategy we find that most of the participants submit complicated strategies and that strategies become more complicated over the rounds most markets converge to a steady state price only after many periods if at all the number of converging price sequences increases over the rounds these results suggest in general slow convergence and learning of the subjects over the rounds even in a stationary environment learning the correct fundamental price level turns out to be difficult an important part of the non convergence seems to be caused not by individual strategies but by the interaction of several strategies from the final experiment we conclude that the strategies are a good representation of what participants do in a laboratory experiment

experimental evidence on the persistence of output and inflation this article presents experimental evidence from a monetary sticky price economy in which output and inflation depend on expected future inflation rational inflation expectations do not allow for persistent deviations of output and inflation following a monetary shock in the experimental sessions however output and inflation display considerable persistence and regular cyclical patterns

how do firms form their expectations new survey evidence author s coibion o gorodnichenko y kumar s abstract 2018 american economic association all rights reserved we survey new zealand firms and document novel facts about their macroeconomic beliefs there is widespread dispersion in beliefs about past and future macroeconomic conditions especially inflation this dispersion in beliefs is consistent with firms incentives to collect and process information using experimental methods we find that firms update their beliefs in a bayesian manner when presented with new information about the economy and that changes in their beliefs affect their decisions inflation is not generally perceived as being important to business decisions so firms devote few resources to collecting and processing information about inflation

dynamic matching and bargaining games a general approach this paper presents a new characterization result for competitive allocations in quasilinear economies this result is informed by the analysis of non cooperative dynamic search and bargaining games such games provide models of decentralized markets with trading frictions a central objective of this literature is to investigate how equilibrium outcomes depend on the level of the frictions in particular does the trading outcome become walrasian when frictions become small existing specifications of such games provide divergent answers the characterization result is used to investigate what causes these differences and to generalize insights from the analysis of specific search and bargaining games

the behavior of the exchange rate in the genetic algorithm and experimental economies this paper studies the behavior of the exchange rate in the kareken wallace overlapping generations economy with two currencies in which decision rules are updated using the genetic algorithm the analysis shows that a stationary monetary equilibrium of the kareken wallace model is not stable under the genetic algorithm dynamics the fluctuations in the genetic algorithm exchange rate are driven by fluctuations in the portfolio fractions which change over time in response to the inequality between the rates of return on two currencies further both the genetic algorithm simulations and the experiments with human subjects were characterized by continuing fluctuations of the exchange rate with first period consumption values close to a stationary value

the rate of convergence to perfect competition of matching and bargaining mechanisms abstract we study the steady state of a market with incoming cohorts of buyers and sellers who are matched pairwise and bargain under private information a friction parameter is the length of the time period until the next meeting we provide a necessary and sufficient condition for the convergence of mechanism outcomes to perfect competition at the linear rate in which is shown to be the fastest possible among all bargaining mechanisms the condition requires that buyers and sellers always retain some bargaining power the bargaining mechanisms that satisfy this condition are called nonvanishing bargaining power nbp mechanisms simple random proposer take it or leave it protocols are nbp while k double auctions k da are not we find that k das have equilibria that converge to perfect competition at a linear rate converge at a slower rate or even do not converge at all

dynamic matching two sided incomplete information and participation costs existence and convergence to perfect competition consider a decentralized dynamic market with an infinite horizon and participation costs in which both buyers and sellers have private information concerning their values for the indivisible traded good time is discrete each period has length and each unit of time continuums of new buyers and sellers consider entry traders whose expected utility is negative choose not to enter within a period each buyer is matched anonymously with a seller and each seller is matched with zero one or more buyers every seller runs a first price auction with a reservation price and if trade occurs both the seller and the winning buyer exit the market with their realized utility traders who fail to trade continue in the market to be rematched we characterize the steady state equilibria that are perfect bayesian we show that as converges to zero equilibrium prices at which trades occur converge to the walrasian price and the realized allocations converge to the competitive allocation we also show the existence of equilibria for sufficiently small provided the discount rate is small relative to the participation

equilibrium in a market with sequential bargaining this paper considers a market where pairs of agents who are interested in carrying out a transaction are brought together by a stochastic process and upon meeting initiate a bargaining process over the terms of the transaction the basic bargaining problem is treated with the strategic approach the paper derives the steady state equilibrium agreements analyzes their dependence on market conditions such as the relative numbers of agents of different types and discusses their relations with the competitive equilibrium outcome and other results in the search equilibrium literature this paper considers a market that operates in the following way pairs of agents who have mutual interest in carrying out a transaction are brought together by a stochastic process when two agents meet they initiate a bargaining process over the terms of the transaction if two agents reach an agreement a transaction takes place and they leave the market of course the bargaining positions and hence the agreement reached in any particular meeting will be affected by the conditions prevailing in the market these will include the chances that each of the negotiating parties have of meeting other partners in the event that the agreement in the current negotiations is delayed also the expected length of time required to achieve an alternative transaction and the expected behavior of alternative partners the study of such a market mechanism is of interest for two reasons firstly it captures some realistic aspects of the trade in certain specific markets e g asset markets such as housing and some labor markets secondly it contributes to an understanding of the micro mechanisms of price formation and their role in shaping market outcomes in both cases the features studied are largely neglected in the traditional market equilibrium analyses the related literature includes the articles by diamond 4 5 diamond and maskin 6 mortensen 8 9 and zusman and bell 13 these articles consider markets of the type described above in which transactions are concluded at pairwise meetings of agents the major difference between our work and these articles is in the approach to the basic bargaining problem in the cited articles it is assumed that a meeting is concluded with an instantaneous agreement which divides the associated surplus in an arbitrary predetermined way when the surplus is assumed to be divided equally the division rule is in fact nash s axiomatic bargaining solution in contrast the present paper treats the basic bargaining problem with the strategic approach see rubinstein 19 which constitutes an attempt to look into the bargaining black box this approach explicitly models the time dimension of the bargaining process describes in detail the bargaining procedure and justifies the agreement as a perfect equilibrium in

search adverse selection and market clearing we examine a dynamic decentralized trading model with infinitesimal sellers and buyers to investigate whether or not the market fails to clear in the limit of search friction vanishing a seller who has private information about product quality and a buyer are matched to bargain over price they form a long term relationship if they reach agreement they return to the matching pool if they fail to agree or the existing relationship is dissolved the market fails to clear if and only if the ratio of agents patience over the dissolution rate exceeds a threshold

null nullifying or dummifying players the difference between the shapley value the equal division value and the equal surplus division value we provide new characterisations of the equal surplus division value this way the difference between the shapley value the equal surplus division value and the equal division value is pinpointed to one axiom

expectational stability of sunspot equilibria in non convex economies we examine the stability under learning e stability of sunspot equilibria in non convex real business cycle models the production technology is cobbdouglas with externalities generated by factor inputs we establish that with a general utility function the well known benhabib farmer condition benhabib and farmer 1994 that the labor demand curve is upward sloping and steeper than the frisch labor supply curve is necessary for joint indeterminacy and e stability then with a separable utility function and allowing for negative externalities from capital inputs we discover large regions in parameter space corresponding to stable indeterminacy that is learnable sunspot equilibria these existence results overturn the conventional wisdom that sunspot equilibria in rbc type models are inherently unstable and provide concise closure to the stability puzzle of evans and mcgough 2005b

an experimental test of an optimal growth model this paper describes the design and behavior of an experimental economy with the structure of the ramsey cass koopmans model of optimal growth the experiment includes three different implementations of the model a decentralized implementation with multiple agents and a market for capital a treatment where individual subjects are placed in the role of social planners and a treatment where the social planner consists of five agents making a joint decision the findings highlight the role of market institutions in facilitating convergence to the optimal steady state jel c91 c92 o40

bank runs as coordination failures an experimental study we use experimental methods to investigate what factors contribute to breakdowns in coordination among a bank s depositors subjects in our experiment decide whether to leave their money deposited in a bank or withdraw it early a bank run occurs when there are too many early withdrawals we explore the effects of adding uncertainty about fundamental withdrawal demand and of changing the number of opportunities subjects have to withdraw our results show that i bank runs are rare when fundamental withdrawal demand is known but occur frequently when it is stochastic and ii subjects are more likely to withdraw when given multiple opportunities to do so than when presented with a single decision for the multiple opportunity case we evaluate individual withdrawal decisions according to a set of simple cutoff rules we find that the cutoff rule corresponding to the payoff dominant equilibrium of the game which involves bayesian updating of probabilities explains subject behavior better than other rules

indeterminacy and increasing returns abstract we investigate properties of the one sector growth model with increasing returns under two organizational structures capable of reconciling the existence of aggregate increasing returns with competitive behavior by firms the first involves input externalities the second involves monopolistic competition we show for parameters in close accord with recent literature on real business cycles that the model displays an indeterminate steady state that can be exploited to generate a model of business fluctuations driven by self fulfilling beliefs in our first class of models growth is generated by exogenous increases in factor productivity in the second class the marginal product of capital is large enough for endogenous growth journal of economic literature classification numbers e00 e3 o40

mechanism design by competing sellers a dynamic model with many sellers and buyers is constructed agents failing to trade may trade in the next period an equilibrium is found where sellers hold identical auctions and buyers randomize over the sellers they visit the distribution of buyer valuations is endogenous an auction with efficient reserve is an optimal mechanism from each seller s point of view in spite of the ability of any seller to alter the distribution of buyer types participating in the seller s mechanism by altering the mechanism copyright 1993 by the econometric society

expectations and bubbles in asset pricing experiments abstract we present results on expectation formation in a controlled experimental environment in each period subjects are asked to predict the next price of a risky asset the realized market price is derived from an unknown market equilibrium equation with feedback from individual forecasts in most experiments prices deviate from the benchmark fundamental and bubbles emerge endogenously these bubbles are inconsistent with rational expectations and seem to be driven by trend chasing behavior or positive feedback expectations of the participants we also analyze individual predictions of participants and find that participants within a group tend to coordinate on a common prediction strategy

a search model of rental markets who should pay the commission abstract we develop a dynamic search equilibrium model of rental markets with brokerage fees an endogenous mass of landlords and tenants is active in the search market while the mass of entering tenants is exogenous the mass of entering landlords is endogenously determined by the rate at which apartments become vacant brokerage fees paid by tenants are used as a device to screen short term and long term tenants we analyze a policy that requires fees to be paid by landlords such a policy decreases efficiency by preventing efficient screening but also increases turnover and hence efficiency in the search market we further provide empirically testable implications of our theory

experiments with network formation abstract we examine how groups of agents form trading networks in the presence of idiosyncratic risk and the possibility of contagion specifically four agents play a two stage finite repeated game in the first stage the network structure is endogenously determined through a non cooperative proposal game in the second stage agents play multiple rounds of a coordination game against all of their chosen neighbors after the realization of a payoff relevant shock while parsimonious our four agent environment is rich enough to capture all of the important interaction structures in the networks literature bilateral marriage local interaction star and uniform matching consistent with our theory marriage networks are the most frequent and stable network structures in our experiments we find that payoff efficiency is around 90 percent of the ex ante payoff dominant strategies and the distribution of network structures is significantly different from that which would result from random play

fiscal policy in an expectations driven liquidity trap we study the effects of fiscal policy interventions in a liquidity trap in a model with nominal rigidities and an interest rate rule in a liquidity trap caused by a self fulfilling state of low confidence higher government spending has deflationary effects that reduce the spending multiplier when the zero lower bound is binding instead cuts in marginal labor tax rates are inflationary and become more expansionary when the zero lower bound is binding these findings contradict popular views about the effects of fiscal policy in a liquidity trap

prices delay and the dynamics of trade we characterize the dynamics of trading patterns and market composition when trade is bilateral finding a trading partner is costly prices are determined by bargaining and preferences are private information we show that equilibrium is inefficient and exhibits delay as sellers price discriminate between buyers with different values as frictions vanish transaction prices are asymptotically competitive and the welfare loss of inefficient trading approaches zero even though the trading patterns continue to be inefficient and delay persists journal of economic literature classification numbers d40 d50

convergence to perfect competition of a dynamic matching and bargaining market with two sided incomplete information and exogenous exit rate abstract consider a decentralized dynamic market with an infinite horizon and incomplete information in which buyers and sellers values for the traded good are private and independently drawn time is discrete each period has length and each unit of time a large number of new buyers and sellers enter the market within a period each buyer is matched with a seller and each seller is matched with zero one or more buyers every seller runs a first price auction with a reservation price and if trade occurs the seller and winning buyer exit with their realized utility traders who fail to trade either continue in the market to be rematched or exit at an exogenous rate we show that in all steady state perfect bayesian equilibria as approaches zero equilibrium prices converge to the walrasian price and realized allocations converge to the competitive allocation

walras retrouve decentralized trading mechanisms and the competitive price we extend the standard analysis of decentralized markets to allow for the possibility that traders interact simultaneously with more than one trader on the opposite side of the market in contrast with the literature we reconcile the walrasian equilibrium with the outcome of decentralized strategic trade we show that there exist generic matching technologies that determine local market conditions such that as market frictions vanish the equilibrium price is the one that would result in the static walrasian market our analysis highlights the importance of local market conditions for the determination of equilibrium prices

bidding for surplus in network allocation problems in this paper we study non cooperative foundations of network allocation rules we focus on three allocation rules the myerson value the position value and the component wise egalitarian solution for any of these three rules we provide a characterization based on component efficiency and some balanced contribution property additionally we present three mechanisms whose equilibrium payoffs are well defined and coincide with the three rules under consideration if the underlying value function is monotonic non monotonic value functions are shown to deal with allocation rules applied to monotonic covers the mechanisms are inspired by the implementation of the shapley value by perez castrillo and wettstein bidding for the surplus a non cooperative approach to the shapley value j econ theory 100 2 2001 274 294

bargaining in stationary networks we study an infinite horizon game in which pairs of players con nected in a network are randomly matched to bargain players who reach agreement are replaced by new players at the same positions in the network we show that all equilibria are payoff equivalent the payoffs and the set of agreement links converge as players become patient several new concepts mutually estranged sets partners and shortage ratios provide insights into the relative strengths of the positions in the network we develop a procedure to deter mine the limit equilibrium payoffs for all players characterizations of equitable and nondiscriminatory networks are also obtained jel c78 d85 competitive equilibrium theory assumes large and anonymous markets in which every buyer can trade with every seller underlying these assumptions are standard goods and services that may be traded at low transaction costs by agents who are not in specific relationships with one another however in many markets goods and services are heterogeneous e g cars apartments or need to be tailored to particular needs e g manufacturing inputs technical support furthermore trad ing opportunities may depend on transportation costs social relationships infor mation advertising trust technological compatibility joint business opportunities free trade agreements etc in such cases it is natural to model the market using a network where only pairs of connected agents may engage in exchange new theories are needed to explore the influence of the network structure on market outcomes many questions arise how does an agent s position in the net work determine his bargaining power and the local prices he faces who trades with whom and on what terms when are prices uniform in the network one possible conjecture is that an agent s bargaining power is determined by his relative number of connections in the network however this simple theory is implausible consider the network of four sellers located at the top nodes and nine buyers located at the bottom nodes depicted in figure 1 assume that each seller supplies one unit of a homogeneous indivisible good each buyer demands one unit of the good and all buyers have identical values for the good the buyer located in the middle has the largest number of links in the network as he is connected to each

the perils of taylor rules abstract since john taylor s 1993 carnegie rochester conf ser publ policy39 195 214 seminal paper a large literature has argued that active interest rate feedback rules that is rules that respond to increases in inflation with a more than one for one increase in the nominal interest rate are stabilizing in this paper we argue that once the zero bound on nominal interest rates is taken into account active interest rate feedback rules can easily lead to unexpected consequences specifically we show that even if the steady state at which monetary policy is active is locally the unique equilibrium typically there exist an infinite number of equilibrium trajectories originating arbitrarily close to that steady state that converge to a liquidity trap that is a steady state in which the nominal interest rate is near zero and inflation is possibly negative journal of economic literature classification numbers e52 e31 e63

monetary policy and rational asset price bubbles i examine the impact of alternative monetary policy rules on a rational asset price bubble through the lens of an olg model with nominal rigidities a systematic increase in interest rates in response to a growing bubble is shown to enhance the uctuations in the latter

competitive pricing and efficiency in search equilibrium we consolidate and generalize some results on price determination and efficiency in search equilibrium extending models by rubinstein and wolinsky and by gale heterogeneous buyers and sellers meet according to a general matching technology and prices are determined by a general bargaining condition when the discount rate r and search costs converge to 0 we show that prices in all exchanges are the same and equal the competitive market clearing price given positive search costs efficiency obtains iff bargaining satisfies hosios condition and r 0 when prices are set by third party market makers however we show that search equilibrium is necessarily efficient

dynamic markets with competitive bidding the model features a dynamic market in steady state in which prices are determined in first price auctions it combines competition over time familiar from the pairwise meeting models with instantaneous bidding competition it inquires how different properties of the model determine the relative importance of these two aspects of the competition and in particular how the non market clearing price result of the matching and bargaining models is affected by the

the power of sunspots an experimental analysis abstract in an experiment using a coordination game with extrinsic random signals sunspots we systematically vary the stochastic process generating these signals and measure how signals affect behavior we find that sunspot equilibria emerge naturally with salient public signals however highly correlated private signals can also lead to sunspot driven behavior even when this is not an equilibrium private signals reduce the power of public signals as sunspot variables the higher the correlation of extrinsic signals and the more easily they can be aggregated the more powerful these signals are in distracting actions from the action that minimizes strategic uncertainty

sunspots in the laboratory we show that extrinsic or nonfundamental uncertainty influences markets in a controlled environment this work provides the first direct evidence of sunspot equilibria these equilibria require a common understanding of the semantics of the sunspot variable and they appear to be sensitive to the flow of information sunspots always occur in a closed book call market but they happen only occasionally in a double auction where inframarginal bids and offers are observable

individual expectations limited rationality and aggregate outcomes recent studies suggest that the type of strategic environment or expectation feedback can have a large impact on whether the market can learn the rational fundamental price we present an experiment where the fundamental price experiences large unexpected shocks markets with negative expectation feedback strategic substitutes quickly converge to the new fundamental while markets with positive expectation feedback strategic complements do not converge but show underreaction in the short run and overreaction in the long run a simple evolutionary selection model of individual learning explains these differences in aggregate outcomes

bilateral matching and bargaining with private information we study equilibria of a dynamic matching and bargaining game dmbg with two sided private information bilateral bargaining the model is a private information replica of mortensen and wright 2002 there are two kinds of frictions time

indeterminacy of equilibria in a hyperinflationary world experimental evidence the authors design and study an olg experimental economy where the government finances a fixed real deficit through seigniorage the economy has continua of nonstationary rational expectations equilibria and two stationary rational expectations equilibria the authors do not observe nonstationary rational expectations paths observed paths tend to converge close to or somewhat below the low inflation stationary state the adaptive learning hypothesis is consistent with the data in selecting the low inflation stationary state rational expectations equilibrium as a long run stationary equilibrium nevertheless simple adaptive learning models do not capture the market uncertainty or the biases observed in the data copyright 1993 by the econometric society

information revelation in a market with pairwise meetings the paper presents a simple pairwise meetings model of trade the new feature is that agents have asymmetric information about the true state of the world the focus is on the transmission of the information through the process of trade the qualitative question is to what extent is the information revealed to uninformed agents through the trading process when the market is in some sense frictionless in particular does the decentralized process give rise to full revelation results as derived by the literature on rational expectations for centralized and competitive environments in the context of the model of this paper it turns out that the information is not fully revealed to uninformed agents even when the market is in some sense approximately frictionless

are sunspots learnable an experimental investigation in a simple macroeconomic model abstract we conduct experiments with human subjects in a model with a positive production externality in which productivity is a nondecreasing function of the average level of employment of other firms the model has three steady states and a sunspot equilibrium that fluctuates between the high and low steady states steady states are payoff ranked low values give lower profits than higher values we investigate whether subjects can learn a sunspot equilibrium we observe coordination on the extrinsic announcements in our experimental economies cases of apparent convergence to the low and high steady states are also observed

fairness and fairness for neighbors the difference between the myerson value and component wise egalitarian solutions abstract we replace the axiom of fairness used in the characterization of the myerson value myerson 1977 by fairness for neighbors in order to characterize the component wise egalitarian solution when a link is broken fairness states that the two players incident to the link should be affected similarly while fairness for neighbors states that a player incident to the link and any of his other neighbors should be affected similarly fairness for neighbors is also used to characterize the component wise egalitarian surplus solution and a two step egalitarian surplus solution these results highlight that egalitarian and marginalistic allocation rules can be obtained by applying the same equal gain loss property to different types of players

genetic algorithms and inflationary economies abstract this paper studies overlapping generations economies in which agents use genetic algorithms to learn correct decision rules the results of computer simulations show that a genetic algorithm converges to the unique monetary steady state in case of a constant money supply policy and to the low inflation stationary equilibrium in case of a constant real deficit financed through seignorage features of the genetic algorithm adaptation are compared to the performance of other learning algorithms and to the behavior observed in experiments with human subjects in the same olg environments

learning by doing short sightedness and indeterminacy this article introduces firm specific learning by doing into a real business cycle rbc model this assumption results in indeterminacy of the wage over a large portion of the parameter space when firms use sufficiently high discount factors and when newly employed labour is relatively unproductive when firms and households use the same discount factor the effects of indeterminacy are limited to adding volatility to the wage rate if these discount factors differ however then indeterminacy also destabilises newly employed labour and total hours this result helps to explain the high amount of volatility that newly employed labour exhibits in the us data

monetary policy and rational asset price bubbles comment we revisit gali s 2014 analysis by extending his model to incorporate persistent bubble shocks we find that under adaptive learning a stable bubbly steady state and the associated sunspot solutions under optimal monetary policy are not e stable when deriving the unique forward looking minimum stable variable msv solution around an unstable bubbly steady state we obtain results that are consistent with the conventional views leaning against the wind policy reduces bubble volatility and is optimal such a steady state and the associated msv solution are e stable

are non fundamental equilibria learnable in models of monetary policy abstract recent models of monetary policy can have indeterminacy of equilibria which is often viewed as a difficulty of these models we consider the significance of indeterminacy using the learning approach to expectations formation we employ expectational stability as a selection criterion for different equilibria and derive the expectational stability and instability conditions for forward looking multivariate models both without and with lags the results are applied to several monetary policies

disagreement in markets with matching and bargaining this paper develops an explanation of why bargainers often terminate negotiations in disagreement in spite of positive expected gains from continued negotiation the key to the analysis is a model which embeds bargaining activity within a market agents are continually faced with the choice between continuing to bargain with an existing partner or searching for a new partner bargainers may then terminate negotiations without an agreement in spite of positive expected gains from continued bargaining because seeking a new bargaining partner promises a higher return

learning forecasting and optimizing an experimental study rational expectations re models have two crucial dimensions i agents on average correctly forecast future prices given all available information and ii given expectations agents solve optimization problems and these solutions in turn determine actual price realizations experimental tests of such models typically focus on only one of these two dimensions in this paper we consider both forecasting and optimization decisions in an experimental cobweb economy we report results from four main experimental treatments 1 subjects form forecasts only 2 subjects determine quantity only solve an optimization problem 3 they do both and 4 they are paired in teams and one member is assigned the forecasting role while the other is assigned the optimization task all treatments converge to rational expectation equilibrium ree but at different speeds we observe that performance is the best in treatment 1 and the worst in treatment 3 we further find that most subjects use adaptive rules to forecast prices given a price forecast subjects are less likely to make conditionally optimal production decisions in treatment 3 where the forecast is made by themselves than in treatment 4 where the forecast is made by the other member of their team which suggests that two heads are better than one in term of the speed of finding the ree

solidarity within a fixed community we study the consequences of a solidarity property that specifies how a value for cooperative games should respond if some player forfeits his productivity i e becomes a null player nullified solidarity states that in this case either all players weakly gain together or all players weakly lose together combined with efficiency the null game property and a weak fairness property we obtain a new characterization of the equal division value

asymmetric information in bilateral trade and in markets an inversion result abstract i consider bilateral trade between a seller and a buyer with private valuations the seller makes a take it or leave it price offer if the seller observes the buyer s valuation symmetric information bilateral trade is trivially efficient if the seller cannot observe the valuation asymmetric information bilateral trade is inefficient this bilateral trading game is embedded into a large matching market in the steady state equilibrium of the market game the relation between the informational regime and efficiency is inverted with small frictions efficiency obtains if information is asymmetric if information is symmetric however the trading outcome can be very inefficient even if frictions vanish