aspiration adaptation in the ultimatum minigame abstract two agents recurrently play a 2 2 version of the ultimatum game each player sticks to his past action if it was satisfactory relative to an endogenous aspiration level and otherwise abandons it with positive probability this type of satisficing behavior is shown to yield efficiency in the limit it does not favor a specific distribution of surplus and can give an explanation for the incidence of equitable offers in practice numerical investigations link a player s character as captured by the model parameters to his average bargaining success results indicate that it is beneficial to be persistent and stubborn i e slow in adapting aspirations and switching actions in response to major dissatisfaction also it is an advantage to be capricious i e to experience large and frequent perturbations of aspiration level and to discriminate only little between minor and major dissatisfaction

sluggish consumers an evolutionary solution to the bertrand paradox we consider an evolutionary model where sellers charge prices for a homogeneous commodity and where consumers while incompletely informed about prices decide from which seller they buy the commodity sellers revise their decisions by way of imitation and experimentation and consumers engage in search consumers are sluggish if they do not learn sellers prices with some positive probability only if consumers are not sluggish at all does economic evolution unambiguously support bertrand equilibrium if consumers are sluggish firms charge other prices as well and the evolutionary process displays a property similar to parallel pricing if consumers are extremely sluggish evolution picks up monopoly pricing journal of economic literature classification numbers c7 d43 d83 l13

does market incompleteness matter this paper argues that incompleteness of intertemporal financial markets has little effect on welfare prices or consumption in an economy with a single consumption good provided that traders are long lived and patient a riskless bond is traded shocks are transitory and there is no aggregate risk in an economy with aggregate risk a similar conclusion holds provided traders share the same crra utility function and the right assets are traded examples demonstrate that these conclusions need not hold if the wrong assets are traded or if the economy has multiple consumption goods

computing multi period information constrained optima this paper presents a detailed theoretical derivation and justification for methods used to compute solutions to a multi period including infinite period continuum agent unobservedeffort economy actual solutions are displayed illustrating cross sectional variability in consumption and labour effort in the population at a point in time and variability for a typical individual over time the optimal tradeoff between insurance and incentives is explored and the issue of excess variability is addressed by consideration of the analogue full information economy and various restricted contracting regimes

unsecured credit markets are not insurance markets abstract we study the extent to which unsecured credit markets have altered the transmission of increased income risk to consumption variability over the past several decades we find that unsecured credit markets pass through increased income risk to consumption irrespective of bankruptcy policy and the information possessed by lenders if risk sharing has indeed improved over this period the reasons do not therefore lie in the unsecured credit market

an evolutionary model of bertrand oligopoly we analyze the long run outcome of markets in which boundedly rational firms with a decreasing returns to scale technology compete in prices the behavior of these firms is based on limitation of success and experimentation in this framework we introduce a new approach to model boundedly rational behavior based on the idea of behavioral principles i e formal descriptions even with the simplest ones the result is that the prices announced are a strict refinement of the set of nash equilibria with more sophisticated behavioral principles the long run outcome corresponds to the concept of central prices wich are also nash equilibria introduced here this is a robust and clear cut prediction wich under quadratic costs and arbitrary demand essentially coincides with the walrasian equilibrium

the effectiveness of government debt and transfers as insurance abstract government debt and redistributive taxation can help people to smooth consumption when facing uninsurable individual specific risk i examine the effects that variations in public debt and transfers have on risk sharing efficiency and the distribution of resources i find that risk sharing can be improved significantly by both debt and transfers but that debt has adverse effects on equity when used in isolation debt will enhance welfare if transfers are lower than optimal however the beneficial effects of public debt vanish if transfers are used optimally

market share dynamics in a duopoly model with word of mouth communication abstract we analyze dynamic price competition in a homogeneous goods duopoly where consumers exchange information via word of mouth communication a fraction of consumers who do not learn any new information remain locked in at their previous supplier in each period we analyze markov perfect equilibria in which firms use mixed pricing strategies market share dynamics are driven by the endogenous price dispersion depending on the parameters we obtain different classes of dynamics when firms are impatient there is a tendency towards equal market shares when firms are patient there are extended intervals of market dominance interrupted by sudden changes in the leadership position

cournot oligopoly characterization and applications preface part 1 introduction 1 introduction purpose and overview andrew f daughety part ii background 2 of the competition of producers augustin cournot translation by nathanial t bacon 3 review of walras s theorie mathematique de la richesse sociale and cournot s reserches sur les principles mathematiques de la theorie des richesses joseph bertrand translation by james w friedman 4 non cooperative games john nash part iii examining cournot s model 5 on the existence of cournot equilibrium william novshek 6 collusive behavior in non cooperative epsilon equilibria of oligopolies with long but finite lives roy radner 7 a non cooperative equilibrium for supergames james w friedman 8 reconsidering cournot the cournot equilibrium is consistent andrew f daughety 9 an experimental test of the consistent conjectures hypothesis charles a holt 10 quantity precommitment and bertrand competition yield cournot outcomes david m kreps and jose a scheinkman 11 on the efficiency of bertrand and cournot equilibria with product differentiation xavier vives 12 price competition vs quantity competition the role of uncertainty paul klemperer and margaret meyer part iv applications 13 cournot and walras equilibrium william novshek and hugo sonnenschein 14 duopoly information equilibrium cournot and bertrand xavier vives 15 information transmission cournot and bertrand equilibria esther gal or 16 uncertainty resolution private information aggregation and the cournot competitive limit thomas r palfrey 17 losses from horizontal merger the effects of an exogenous change in industry structure on cournot nash equilibrium stephen w salant sheldon switzer and robert j reynolds 18 delegation and the theory of the firm john vickers 19 a study of cartel stability the joint executive committee 1880 1886 robert h porter 20 oligopoly and financial structure the limited liability effect james a brander and tracy r lewis

survival at the center the stability of minimum differentiation abstract we model a hotelling market with multidimensional product differentiation in an evolutionary framework both evolutionary stability in the sense of schaffer 1989 and stochastic stability following kandori et al 1993 young 1993 are analyzed it is shown that firms move towards the center in product space i e a principle of minimum differentiation on all dimensions of the product space applies

the welfare cost of business cycles revisited finite lives and cyclical variation in idiosyncratic risk abstract this paper investigates the welfare costs of business cycles in a heterogeneous agent overlapping generations economy which is distinguished by idiosyncratic labor market risk aggregate variation arises both in terms of aggregate productivity shocks and countercyclical variation in the volatility of idiosyncratic shocks based on both aggregate data and microeconomic data from the panel study on income dynamics we find the welfare benefits of eliminating aggregate variation to be large an order of magnitude larger than those originally documented by lucas 1987 the key difference is countercyclical variation in idiosycratic risk which both amplifies the welfare cost of aggregate productivity shocks and imposes a cost of its own the magnitude of these effects increases non linearly in risk aversion our results therefore are consistent with the increasingly popular notion that distributional effects are an important aspect of understanding the welfare cost of business cycles

consumer bankruptcy a fresh start consumer bankruptcy provides partial insurance against bad luck but by driving up interest rates makes life cycle smoothing more difficult we argue that to assess this trade off one needs a quantitative model of consumer bankruptcy with three key features life cycle component idiosyncratic earnings uncertainty and expense uncertainty exogenous negative shocks to household balance sheets we find that transitory and persistent earnings shocks have very different implications for evaluating bankruptcy rules more persistent shocks make the bankruptcy option more desirable larger transitory shocks have the opposite effect our findings suggest the current us bankruptcy system may be desirable for reasonable parameter values jel d14 d91 k35

relative wage movements and the distribution of consumption we analyze how relative wage movements among birth cohorts and education groups affected the distribution of household consumption and economic welfare our empirical work draws on the best available cross sectional data sets to construct synthetic panel data on u s consumption labor supply and wages during the 1980s we find that low frequency movements in the cohort education structure of pretax hourly wages among men drove large changes in the distribution of household consumption the results constitute a spectacular failure of between group consumption insurance a failure not explained by existing theories of informationally constrained optimal consumption behavior a welfare analysis indicates that the cost of between group consumption variability is larger than the cost of aggregate consumption variability by two orders of magnitude

saving and liquidity constraints this paper is concerned with the theory of saving when consumers are not permitted to borrow and with the ability of such a theory to account for some of the stylized facts of saving behavior the models presented in the paper seem to account for important aspects of reality that are not explained by traditional life cycle models copyright 1991 by the econometric society

repeated partnerships with multiple equilibria and imperfect monitoring an experimental study abstract i investigate finitely repeated partnership games with imperfect monitoring where both mutual effort and mutual shirking are nash equilibria of the stage game the treatment variable is the number of repetitions i find that period 1 effort rates are increasing in the number of repetitions but subjects use trigger strategies that switch to permanent shirking after enough failed projects so effort rates decrease across time in all treatments additionally the rate of decrease is less when there are more repetitions total effort does not vary much across the treatments because the increased period 1 effort when the number of repetitions is large is mostly canceled out by the erosion of effort as the game progresses

oligopolistic pricing with sequential consumer search n identical stores compete by choosing prices for a homogeneous good with constant marginal costs consumers search sequentially with perfect recall for the lowest price one class of consumers called shoppers have zero search costs while all other consumers have a positive search cost c there is a unique symmetric nash equilibrium price distribution with the property that it changes smoothly from marginal cost pricing when all consumers are shoppers and or c 0 and monopoly pricing when no consumers are shoppers remarkably as the number of stores increases the nash equilibrium becomes more monopolistic copyright 1989 by american economic association

insurance and opportunities a welfare analysis of labor market risk abstract using a model with constant relative risk aversion preferences endogenous labor supply and partial insurance against idiosyncratic wage risk this paper provides an analytical characterization of three welfare effects a the welfare effect of a rise in wage dispersion b the welfare gain from completing markets and c the welfare effect from eliminating risk the analysis reveals an important trade off for these welfare calculations on the one hand higher wage uncertainty increases the cost associated with missing insurance markets on the other hand greater wage dispersion presents opportunities to raise aggregate productivity by concentrating market work among more productive workers welfare effects can be expressed in terms of the underlying parameters defining preferences and wage risk or alternatively in terms of changes in observable second moments of the joint distribution over individual wages consumption and hours

opportunity and social mobility the fact that the children of rich parents have better economic prospects than the children of poor parents unequal opportunity is generally thought to be one of the weak points of modem capitalist societies the ability of the descendants of poor families to eventually become rich and the descendants of rich families to eventually become poor social mobility is commonly considered to be one of the strong points of these societies here i argue that both of these characteristics are in fact necessary implications of an efficient societal arrangement when incentives to work hard must be provided i argue this point using a generational version of the model of phelan and townsend 1991 an infinitely repeated general equilibrium economy with incentive constraints in my model each household s stochastic output is a function of its level of effort since effort is assumed to be costly and privately observed households can shirk higher than minimal effort levels must be induced by making a household s present or future consumption dependent on the household s observed output history a large literature considers models similar to this including green 1987 atkeson and lucas 1992 phelan 1994 1995 wang 1995 hopenhayn and nicolini 1997 khan and ravikumar 2002 the main difference between the economies in that literature and here is that here instead of a household consisting of a single infinitely lived individual a household consists of a sequence of altruistically linked individuals a familial dynasty each of whom lives for one period this difference affects the appropriate societal ranking of allocations when households consist of a single infinitely lived individual allocations can be ranked according to their implied distributions of ex ante lifetime utilities if one allocation delivers a distribution of ex ante utilities dominated by another allocation then the first allocation is inefficient however if a household consists of a sequence of altruistically linked individuals then the appropriate ranking of allocations is no longer obvious how those in the first generation rank allocations will in general differ from how their descendants rank allocations this paper addresses this conflict between generations by ranking allocations according to a rawlsian veil of ignorance criterion rawls 1971 that is here society seeks to maximize the expected dynastic utility utility including altruism toward descendants of an individual who does not know into which generation he will be born and the identity or output levels of his ancestors 1 i argue that this corresponds to a societal ranking which does

insurance within the firm we evaluate the allocation of risk between firms and their workers using matched employer employee panel data unlike previous contributions this paper focuses on idiosyncratic shocks to the firm which are the correct empirical counterpart of the theoretical notion of diversifiable risk we allow for both temporary and permanent shocks to output and find that firms absorb temporary fluctuations fully but insure workers against permanent shocks only partially risk sharing considerations can account for about 15 percent of overall earnings variability the remainder originating from idiosyncratic shocks to individual workers our welfare calculations indicate that firms are an important vehicle of insurance provision

collusion as public monitoring becomes noisy experimental evidence this paper uses laboratory experiments to test the implications of the theory of repeated games on equilibrium payoffs and estimate strategies in an infinitely repeated prisoners dilemma game with imperfect public monitoring we find that subjects payoffs i decrease as noise increases and ii are lower than the theoretical maximum for low noise but exceed it for high noise under the assumption that the subjects strategy uses thresholds on the public signal for transition between cooperation and punishment states we find that the best fitting strategy simply compares the most recent public signal against a single threshold

insurance and opportunities the welfare implications of rising wage dispersion this paper develops a series of heterogeneous agents economies in order to characterize analytically the welfare implications of changes in the uncertainty in individual labor productivity we perform two types of welfare calculations first we compute the welfare consequences of a rise in labor market risk given a particular asset market structure complete markets incomplete markets autarky second we compute the expected gain from completing markets starting from autarky or incomplete markets for a given level of wage dispersion we are able to derive intuitive closed form expressions for these welfare eects which depend only on preference parameters and the size of the change in wage dispersion a higher level of productivity dispersion has always two eects it tends to reduce welfare in presence of partial insurance but it also tends to improve production opportunities in presence of flexible labor supply we can separate analytically the insurance and the opportunity components we quantify the welfare consequences of the rise in wage inequality observed in the united states over the past three decades as roughly 3 of lifetime consumption moreover we calculate that completing the asset markets given the current level of inequality would lead to a welfare improvement equivalent to 35 of lifetime consumption

consumption inequality and income uncertainty this paper places the debate over using consumption or income in studies of inequality growth in a formal intertemporal setting it highlights the importance of permanent and transitory income uncertainty in the evaluation of growth in consumption inequality we derive conditions under which the growth of variances and covariances of income and consumption can be used to separately identify the growth in the variance of permanent and transitory income shocks household data from britain for the period 1968 1992 are used to show a strong growth in transitory inequality toward the end of this period while younger cohorts are shown to face significantly higher levels of permanent inequality

the macroeconomic implications of rising wage inequality in the united states in recent decades american workers have faced a rising college premium a narrowing gender gap and increasing wage volatility this paper explores the quantitative and welfare implications of these changes the framework is an incomplete markets life cycle model in which individuals choose education intrafamily time allocation and savings given the observed history of the u s wage structure the model replicates key trends in cross sectional inequality in hours worked earnings and consumption recent cohorts enjoy welfare gains on average as higher relative wages for college graduates and for women translate into higher educational attainment and a more even division of labor within the household

tax and education policy in a heterogeneous agent economy what levels of redistribution maximize growth and efficiency this paper studies the effects of progressive income taxes and education finance in a dynamic heterogeneous agent economy such redistributive policies entail distortions to labor supply and savings but also serve as partial substitutes for missing credit and insurance markets the resulting tradeoffs for growth and efficiency are explored both theoretically and quantitatively in a model that yields complete analytical solutions progressive education finance always leads to higher income growth than taxes and transfers but at the cost of lower insurance overall efficiency is assessed using a new measure that properly reflects aggregate resources and idiosyncratic risks but unlike a standard social welfare function does not reward equality per se simulations using empirical parameter estimates show that the efficiency costs and benefits of redistribution are generally of the same order of magnitude resulting in plausible values for the optimal rates aggregate income and aggregate welfare provide only crude lower and upper bounds around the true efficiency tradeoff

consumption and labor supply with partial insurance an analytical framework we develop a model with partial insurance against idiosyncratic wage shocks to quantify risk sharing closed form solutions are obtained for equilibrium allocations and for moments of the joint distribution of consumption hours and wages we prove identification and demonstrate how labor supply data are informative about risk sharing the model estimated with us data over the period 1967 2006 implies that i 39 percent of permanent wage shocks pass through to consumption ii the share of wage risk insured increased until the early 1980s and iii preference heterogeneity is important in accounting for observed dispersion in consumption and hours jel e21 e23 e31 e52

informative price advertising in a sequential search model the purpose of this paper is to study the role and implications of price advertising when shopping trips are costly to consumers to do so we introduce advertising into an optimal sequential search model information about prices is both gathered by consumers and disseminated by firms consumers search sequentially and stores advertise with various intensity when it is in their interest to do so our model has a unique equilibrium exhibiting priee dispersion the model generates predictions about the shape of the price distribution and firms advertising behavior we explore the effects of entry and find that when initial advertising costs at zero level of effort are precisely zero entry drives the equilibrium to the perfectly competitive outcome however when initial marginal advertising costs are positive entry drives prices higher and while the informed consumers almost surely locate competitive prices welfare does not necessarily increase finally we compare the effectiveness of the two informational channels when advertising costs shrink prices become competitive however when search costs shrink prices remain bounded above marginal production costs

on efficient distribution with private information this paper is a study of the dynamics of the efficient distribution of consumption in an exchange economy with many consumers each of whom is subject to private idiosyncratic taste shocks we propose a recursive method for finding feasible allocations that are incentivecompatible and that are pareto optimal within this set the method is applied to several parametric examples we find that in an efficient allocation the degree of inequality continually increases with a diminishing fraction of the population receiving an increasing fraction of the resources we discuss the extent to which these allocations can be decentralized via market arrangements this paper is a study of the dynamics of the efficient distribution of consumption in an exchange economy with private information the economy we study has a constant endowment flow of a single non storable consumption good which is to be allocated each period among a large number of consumers each period these consumers experience unpredictable idiosyncratic privately observed taste shocks affecting their marginal utility of current consumption efficiency dictates that more resources be allocated to those consumers who in any given period have a high marginal utility of current consumption

why has house price dispersion gone up we calibrate a dynamic general equilibrium island model to investigate the 30 year increase in the level of house prices and their dispersion across u s metropolitan areas the model is based on two main assumptions households o w in and out metropolitan areas in response to local productivity shocks and the housing supply cannot adjust instantly because of technological and regulatory constraints the calibration reveals that the observed tightening of housing supply regulation cannot quantitatively account for the rise in the level and dispersion of house prices in equilibrium workers o w out of tightly regulated towards less regulated metropolitan areas undoing most of the price impact of local supply restrictions in contrast the observed increase in wage dispersion across metropolitan areas does create the observed increase in the level and dispersion of house prices workers o w towards exceptionally productive metropolitan areas and drive house prices up the calibration also suggests that the welfare eects of housing supply regulation are large when wages become more dispersed

a simple test of consumption insurance are consumers effectively insured against idiosyncratic shocks to income or wealth either by formal institutions such as charities private insurance and government programs or by informal mechanisms such as gifts and loans from relatives friends and neighbors under full insurance consumption growth should be cross sectionally independent of idiosyncratic variables that are exogenous to consumers this proposition is tested by cross sectional regressions of consumption growth on a variety of exogenous variables full insurance is rejected for long illness and involuntary job loss but not for spells of unemployment loss of work due to strike and an involuntary move

cooperation in the finitely repeated prisoner s dilemma more than half a century after the first experiment on the finitely repeated prisoner s dilemma evidence on whether cooperation decreases with experience as suggested by backward induction remains inconclusive this paper provides a meta analysis of prior experimental research and reports the results of a new experiment to elucidate how cooperation varies with the environment in this canonical game we describe forces that affect initial play formation of cooperation and unraveling breakdown of cooperation first contrary to the backward induction prediction the parameters of the repeated game have a significant effect on initial cooperation we identify how these parameters impact the value of cooperation as captured by the size of the basin of attraction of always defect to account for an important part of this effect second despite these initial differences the evolution of behavior is consistent with the unraveling logic of backward induction for all parameter combinations importantly despite the seemingly contradictory results across studies this paper establishes a systematic pattern of behavior subjects converge to use threshold strategies that conditionally cooperate until a threshold round and conditional on establishing cooperation the first defection round moves earlier with experience simulation results generated from a learning model estimated at the subject level provide insights into the long term dynamics and the forces that slow down the unraveling of cooperation

old sick alone and poor a welfare analysis of old age social insurance programmes all individuals face some risk of ending up old sick alone and poor is there a role for social insurance for these risks and if so what is a good programme a large literature has analysed the costs and benefits of pay as you go public pensions and found that the costs exceed the benefits this article instead considers means tested social insurance mtsi programmes for retirees such as medicaid and supplemental security income we find that the welfare gains from these programmes are large moreover the current scale of mtsi in the u s is too small in the following sense if we condition on the current social security programme increasing the scale of mtsi by 1 3 benefits both the poor and the affluent when a payroll tax is used to fund the increase

cost of business cycles with indivisibilities and liquidity constraints it is almost universally agreed that individuals face incomplete insurance markets and cannot perfectly insure against the idiosyncratic risk in this paper simple general equilibrium models with incomplete insurance markets are examined in order to assess the impact of imperfect insurance on the magnitude of the welfare costs of business cycles two versions of incomplete insurance markets are considered and certain statistical properties of the equilibrium stochastic processes in these environments are compared with those of a perfect insurance economy

which workers get insurance within the firm abstract industry level time series data suggest that low skilled workers get less insurance within the firm than high skilled workers in particular wages respond relatively more to productivity shocks in low skilled industries than high skilled industries our theory is that low skilled workers get relatively less insurance from their firms because they have relatively lower displacement costs under limited commitment lower displacement costs make the workers outside options more attractive and hence decrease the amount of risk sharing sustainable within the firm evidence on average displacement costs by industry support the theory s predictions

the evolution of cooperation in infinitely repeated games experimental evidence 1 for example in infinitely repeated prisoner s dilemma games with patient agents both cooperate and defect may be played in equilibrium even though the theory of infinitely repeated games has been used to explain cooperation in a variety of environments no definitive solution has been provided to the problem of equilibrium selection when both cooperation and defection are possible equilibrium outcomes which one should we expect to prevail previous experimental evidence has shown that subjects often fail to coordinate on a specific equilibrium when they play a small number of infinitely repeated games some subjects attempt to establish cooperative agreements while others defect but how would behavior evolve as subjects learn from previous repeated games would cooperation prevail when it can be supported in equilibrium or will subjects learn

human capital and earnings distribution dynamics abstract earnings heterogeneity plays a crucial role in modern macroeconomics we document that mean earnings and measures of earnings dispersion and skewness all increase in us data over most of the working life cycle for a typical cohort as the cohort ages we show that i a human capital model can replicate these properties from the right distribution of initial human capital and learning ability ii differences in learning ability are essential to produce an increase in earnings dispersion over the life cycle and iii differences in learning ability account for the bulk of the variation in the present value of earnings across agents these findings emphasize the need to further understand the role and origins of initial conditions

cournot versus walras in dynamic oligopolies with memory abstract this paper explores the impact of memory in cournot oligopolies where firms learn through imitation of success as suggested in alchian j polit econ 57 1950 211 and modeled in vega redondo econometrica 65 1997 375 as long as memory includes at least one period the long run outcome corresponds to any quantity between the cournot one and the walras one the evolutionary stability of the walrasian outcome relies on interfirm comparisons of simultaneously observed profits i e whether a firm earns more than others in a given period whereas the stability of the cournot nash equilibrium is derived from intertemporal comparisons of profits for each given firm i e whether a deviation pays off for that firm

is the extended family altruistically linked direct tests using micro data this paper uses panel study of income dynamics data on parents and their adult children to test the standard altruism model this model predicts that within the extended family the distribution of consumption is independent of the distribution of resources the authors findings strongly reject this prediction copyright 1992 by american economic association