welfare implications of the transition to high household debt abstract aggressive deregulation of the mortgage market in the early 1980s triggered innovations that greatly reduced indebted households required home equity and a borrowing surge followed this paper uses a calibrated general equilibrium model of lending from the wealthy to the middle class to evaluate the welfare effects of this reform quantitatively we find that the indirect effects of endogenous interest rate and other relative price changes dominate the direct effect of relaxing the constraint the borrowing household s welfare falls even though the reform directly relaxes a constraint on its trade the saving household s welfare rises substantially

perfect foresight and equilibrium selection in symmetric potential games the equilibrium selection approach of matsui and matsuyama j econ theory65 1995 415 434 which is based on rational players who maximize their discounted future payoff is analyzed for symmetric two player games with a potential function it is shown that the maximizer of the potential function is the unique state that is absorbing and globally accessible for small discount rates journal of economic literatureclassification number c72

scientific ambiguity and climate policy economic evaluation of climate policy traditionally treats uncertainty by appealing to expected utility theory yet our knowledge of the impacts of climate policy may not be of sufficient quality to be described by unique probabilistic beliefs in such circumstances it has been argued that the axioms of expected utility theory may not be the correct standard of rationality by contrast several axiomatic frameworks have recently been proposed that account for ambiguous knowledge in this paper we apply static and dynamic versions of a smooth ambiguity model to climate mitigation policy we obtain a general result on the comparative statics of optimal abatement and ambiguity aversion and then extend our analysis to a more realistic dynamic setting where we introduce scientific ambiguity into the well known dice model of the climate economy system for policy relevant exogenous mitigation policies we show that the value of emissions abatement increases as ambiguity aversion increases and that this ambiguity premium can in some plausible cases be very large in these cases the effect of ambiguity aversion on welfare is comparable to that of other much studied welfare parameters thus ambiguity aversion may be an important neglected aspect of climate change economics and seems likely to provide another argument for strong abatement policy

credit supply and the housing boom an increase in credit supply driven by looser lending constraints in the mortgage market is the key force behind four empirical features of the housing boom before the great recession the unpreced

stochastic stability in a double auction abstract in a k double auction a buyer and a seller must simultaneously announce a bid and an ask price respectively exchange of the indivisible good takes place if and only if the bid is at least as high as the ask the trading price being the bid price with probability k and the ask price with probability 1 k we show that the stable equilibria of a complete information k double approximate an asymmetric nash bargaining solution with the seller s bargaining power decreasing in k note that ceteris paribus the payoffs of the seller of the one shot game increase in k nevertheless as the stochastically stable equilibrium price decreases in k choosing the seller s favorite price with a relatively higher probability in individual encounters makes him worse off in the long run

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

the stability and effectiveness of climate coalitions a comparative analysis of multiple integrated assessment models we report results from a comparison of numerically calibrated game theoretic integrated assessment models that explore the stability and performance of international coalitions for climate change mitigation we identify robust results concerning the incentives of different nations to commit themselves to a climate agreement and estimate the extent of greenhouse gas mitigation that can be achieved by stable agreements we also assess the potential of transfers that redistribute the surplus of cooperation to foster the stability of climate coalitions in contrast to much of the existing analytical game theoretical literature we find substantial scope for self enforcing climate coalitions in most models that close much of the abatement and welfare gap between complete absence of cooperation and full cooperation this more positive message follows from the use of appropriate transfer schemes that are designed to counteract free riding incentives

inflation and welfare in a monetary economy it is in everyone s private interest to try to get someone else to hold non interest bearing cash and reserves but someone has to hold it all so these efforts must simply cancel out all of us spend several hours per year in this effort and employ thousands of talented and highly trained people to help us these person hours are simply thrown away wasted on a task that should not have to be performed at all

climate change policy what do the models tell us very little a plethora of integrated assessment models iams have been constructed and used to estimate the social cost of carbon scc and evaluate alternative abatement policies these models have crucial flaws that make them close to useless as tools for policy analysis certain inputs e g the discount rate are arbitrary but have huge effects on the scc estimates the models produce the models descriptions of the impact of climate change are completely ad hoc with no theoretical or empirical foundation and the models can tell us nothing about the most important driver of the scc the possibility of a catastrophic climate outcome iam based analyses of climate policy create a perception of knowledge and precision but that perception is illusory and misleading jel c51 q54 q58

why sunk costs matter for bargaining outcomes an evolutionary approach abstract two bargaining parties play the nash demand game to share a pie whose size is determined by one party s investment decision various investment levels are subgame perfect adding the investment decision to young s evolutionary bargaining model yields the following long run outcome efficient investment prevails and the investor s share of the pie approximates die maximum of i the smallest share that induces efficient investment even if the investor expects to appropriate the available pie from every inefficient investment and ii half of the pie the result favors forward induction to subgame consistency and equity theory to hold ups journal of economic literature classification numbers c78 l14

on the limits to rational learning abstract this paper summarizes recent work of foster and young 2001 which shows that some games are unlearnable in principle by perfectly rational players that is under any learning rule including bayesian updating of common priors the players strategies fail to come close to nash equilibrium with probability one furthermore at least one of them is unable to predict the behavior of the other in an asymptotic sense this result can be interpreted as an uncertainty principle that applies to some kinds of interactive learning problems

financial intermediation house prices and the welfare effects of the u s great recession abstract this paper quantifies the welfare costs of the great recession in the united states and their distribution between borrowing and saving households we use a calibrated dynamic general equilibrium model with shocks to aggregate income and to the financial intermediation sector the model matches the boom bust cycle in house prices the dynamics of household leverage and the increase in inequality of wealth observed in the u s after 2007 we find large welfare costs for financially constrained households the borrowers savers instead benefited from a redistribution of housing wealth due to the de leveraging of borrowers caused by the plunge in house prices this redistribution mechanism was exacerbated by the financial intermediation shock we also show that the welfare costs for borrowers would have been lower if aggregate leverage had remained at pre 2001 levels

the housing market s of san diego this paper uses an assignment model to understand the cross section of house prices within a metro area movers demand for housing is derived from a lifecycle problem with credit market frictions equilibrium house prices adjust to assign houses that dier by quality to movers who dier by age income and wealth to quantify the model we measure distributions of house prices house qualities and mover characteristics from micro data on san diego county during the 2000s boom the main result is that cheaper credit for poor households was a major driver of prices especially at the low end of the market

an efficient and almost budget balanced cost sharing method for a convex technology c we characterize cost sharing games where the nash equilibrium demands maximize total surplus budget balance is possible if and only if c is polynomial of degree n 1 or less for general c the residual cost shares are balanced if at least one demand is null a characteristic property if the cost function is totally monotone a null demand receives cash and total payments may exceed actual cost the ratio of excess payment to efficient surplus is at most min 2logn 1 for power cost functions c a ap p 1 the ratio of budget imbalance to efficient surplus vanishes as 1np 1 for analytic cost functions the ratio converges to zero exponentially along a given sequence of users all asymptotic properties are lost if the cost function is not smooth

housing dynamics over the business cycle housing construction measured by housing starts leads gdp in a number of countries measured as residential investment the lead is observed only in the united states and canada elsewhere residential investment is coincident variants of existing theory however predict housing construction lagging gdp in all countries in the sample nominal interest rates are low ahead of gdp peaks introducing long term nominal mortgages and an estimated process for nominal interest rates into a standard model aligns the theory with observations on starts as mortgages transmit nominal rates into real housing costs longer time to build makes residential investment cyclically coincident abstract from author

housing finance and monetary policy we document three facts concerning how the structure of housing finance affects the monetary transmission mechanism first the characteristics of residential mortgage markets differ markedly across industrialized countries second the impact of monetary policy shocks to residential investment and house prices is significantly stronger in those countries with larger flexibility development of mortgage markets third the transmission to consumption is stronger only in those countries where mortgage equity release is common and mortgage contracts are predominantly of the variable rate type we then build a two sector dsge model with financial constraints to rationalize those facts

competitive behavior in market games evidence and theory we explore whether competitive outcomes arise in an experimental implementation of a market game introduced by shubik 1972 market games obtain pareto inferior strict nash equilibria in which some markets are closed we find that subjects do not coordinate on autarkic nash equilibria but favor more efficient nash equilibria in which all markets are open as the number of subjects participating in the market game increases the nash equilibrium they achieve approximates the associated walrasian equilibrium of the underlying economy motivated by these findings we investigate theoretically whether evolutionary forces lead to walrasian outcomes in market games we introduce a strong version of evolutionary stable strategies sess f orfinite populations our concept requires stability against deviations by coalitions of agents a small coalition of trading agents is sufficient for pareto improving trade to be generated in addition provided that agents lack market power nash equilibria corresponding to approximate competitive outcomes constitute the only approximate sess

adaptive dynamics in games played by heterogeneous populations consider a population of agents who play a game through repeated interactions and adapt their behavior based on information about other agents previous behavior the standard way of modeling such a process is to assume that everyone in the population is governed by the same adaptive rule e g best response imitation or the replicator dynamic this paper studies heterogeneous populations of agents in which some agents are best responders others are conformists they do what the majority does and still others are nonconformists they do the opposite of what the majority does unlike deterministic best reply processes which in 2 2 games converge to nash equilibrium these heterogeneous processes may have limit cycles moreover limit cycles may exist even when the proportion of non best responders is arbitrarily small we show how to analyze the asymptotic behavior of such processes through a suitable generalization of bendixson stability theory combined with stochastic approximation theory journal of economic literature classification numbers c44 c73 d83

the external costs of nuclear power ex ante damages and lay risks interest has been growing in embedding the external costs of fuel cycles resulting in electricity generation into prices in any attempt to internalize these costs for the nuclear cycle the remost but real possibilities of accidents and the wide gap between lay perceptions and expert assessments of such risks must be taken into account this paper discusses this including the following topics an expected utility model of power plant operations accident risks simulation comparison of experts versus lay risks comparison of experts versus lay risk literature simulation of expert versus lay risks current practice in estimating the damages from accidents at nuclear power plants appear to ignore significant features of the problem from the perspective of economic analysis individual aversion to risk the exante perspective in decision making under uncertainty and lay risk perception are all conceptually important elements of a damage estimate that accords with observation of behavior and the theory that underlies it but that are ignored by common practice 18 refs 1 tab

an evolutionary model of bargaining abstract individuals from two populations of bargainers are randomly matched to play the nash demand game they make their demands by choosing best replies based on an incomplete knowledge of the precedents and occasionally they choose randomly there is no common knowledge over the long run typically one division will be observed almost all of the time this stochastically stable division is close to the nash solution when all agents in the same population are alike when the populations are heterogeneous a generalization of the nash solution results if there is some mixing between the two populations the stable division is fifty fifty journal of economic literature classification number c78

inequality leverage and crises the paper studies how high leverage and crises can arise as a result of changes in the income distribution empirically the periods 1920 1929 and 1983 2007 both exhibited a large increase in the income share of the rich a large increase in leverage for the remainder and an eventual financial and real crisis the paper presents a theoretical model where these features arise endogenously as a result of a shift in bargaining powers over incomes a financial crisis can reduce leverage if it is very large and not accompanied by a real contraction but restoration of the lower income group s bargaining power is more effective

a learning approach to auctions we analyze a repeated first price auction in which the types of the players are determined before the first round it is proved that if every player is using either a belief based learning scheme with bounded recall or a generalized fictitious play learning scheme then for sufficiently large time the players bids are in equilibrium in the one shot auction in which the types are commonly known

fictitious play property for games with identical interests abstract ann person game has identical interests if it is best response equivalent in mixed strategies to a game with identical payoff functions it is proved that every such game has the fictitious play property journal of economic literatureclassification numbers c72 c73

the evolution of exchange abstract stochastic stability is applied to the problem of exchange we analyze the stochastic stability of two dynamic trading processes in a simple housing market in both models traders meet in pairs at random and exchange their houses when trade is mutually beneficial but occasionally they make mistakes the models differ in the probability of mistakes when all mistakes are equally likely the set of stochastically stable allocations contains the set of efficient allocations when more serious mistakes are less likely the stochastically stable states are those allocations always efficient with the lowest envy level

building risk into the mitigation adaptation decisions simulated by integrated assessment models this paper proposes an operationally simple and easily generalizable methodology to incorporate climate change damage uncertainty into integrated assessment models iams first uncertainty is transformed into a risk measure by extracting damage distribution means and variances from an ensemble of socio economic and climate change scenarios then a risk premium is computed under different degrees of risk aversion quantifying what society would be willing to pay to insure against the uncertainty of the damages our estimates show that the premium for the risk is a potentially significant addition to the standard average damage but highly sensitive to the attitudes toward risk in the last research phase the risk premium is incorporated into the climate change damage function of a widely used iam which shows consequently a substantial increase in both mitigation and adaptation efforts reflecting a more precautionary attitude by the social planner interestingly adaptation is stimulated more than mitigation in the first half of this century while the situation reverses afterwards

does evolution solve the hold up problem abstract the paper examines the theoretical foundations of the hold up problem at the first stage one agent decides on the level of a relationship specific investment there is no contract so at the second stage the agent must bargain with a trading partner over the surplus that the investment has generated we show that the conventional underinvestment result hinges crucially both on the assumed bargaining game and on the choice of equilibrium concept in particular we prove the following two results i if bargaining proceeds according to the nash demand game any investment level is subgame perfect but only a particular efficient outcome is stochastically stable ii if bargaining proceeds according to the ultimatum game with the trading partner as proposer only the minimal investment level is subgame perfect but any investment level is stochastically stable journal of economic literature classification numbers l14 c78

a dynamic model of housing demand estimation and policy implications in the u s macroeconomic policy makers are concerned about how consumers will respond to falling incomes nominal home prices falling income rising mortgage interest rates and tightening credit standards in order to address these questions we estimate and simulate a dynamic structural model of housing demand in the model consumers maximize expected discounted lifetime utility from housing services and a composite consumption good the model allows for realistic features of the housing market including non convex adjustment costs from buying and selling a home and credit constraints from minimum downpayment requirements we use the forward simulation procedure of bajari benkard and levin 2007 to estimate the structural parameters especially the elasticity of substitution between consumption and housing services using data from the panel study of income dynamics given the estimated model parameters we simulate the partial equilibrium consumption and housing and

the structure of economic modeling of the potential impacts of climate change grafting gross underestimation of risk onto already narrow science models scientists describe the scale of the risks from unmanaged climate change as potentially immense however the scientific models because they omit key factors that are hard to capture precisely appear to substantially underestimate these risks many economic models add further gross underassessment of risk because the assumptions built into the economic modeling on growth damages and risks come close to assuming directly that the impacts and costs will be modest and close to excluding the possibility of catastrophic outcomes a new generation of models is needed in all three of climate science impact and economics with a still stronger focus on lives and livelihoods including the risks of large scale migration and conflicts

house prices borrowing constraints and monetary policy in the business cycle i develop a general equilibrium model with sticky prices credit constraints nominal loans and asset prices changes in asset prices modify agents borrowing capacity through collateral value changes in nominal prices affect real repayments through debt deflation monetary policy shocks move asset and nominal prices in the same direction and are amplified and propagated over time the financial accelerator is not constant across shocks nominal debt stabilises supply shocks making the economy less volatile when the central bank controls the interest rate i discuss the role of equity debt indexation and household and firm leverage in the propagation mechanism finally i find that monetary policy should not target asset prices as a means of reducing output and inflation volatility

learning in games with strategic complementarities revisited fictitious play is a classical learning process for games and games with strategic complementarities are an important class including many economic applications knowledge about convergence properties of fictitious play in this class of games is scarce however beyond games with a unique equilibrium global convergence has only been claimed for games with diminishing returns v krishna learning in games with strategic complementarities hbs working paper 92 073 harvard university 1992 this result remained unpublished and it relies on a specific tie breaking rule here we prove an extension of it by showing that the ordinal version of strategic complementarities suffices the proof does not rely on tie breaking rules and provides some intuition for the result

time horizon and the discount rate abstract we consider an economy a la lucas 1978 econometrica46 1429 1446 with a risk averse representative agent the exogenous growth rate of the economy follows a random walk we characterize the set of utility functions for which it is efficient to discount more distant cash flows at a lower rate the benchmark result is that when the growth rate is almost surely nonnegative the yield curve is decreasing if and only if relative risk aversion is decreasing with wealth relaxing the assumption on the absence of recession requires more restrictions on preferences such as increasing relative prudence journal of economic literature classification numbers d81 d91 q25 q28

iterative computation of cournot equilibrium abstract in a homogeneous coumot model with quasi concave profit functions the problem of determining an equilibrium can be posed as one of solving an equation in one real variable total sales if the response functions are monotone or firms are identical then a certain iterative process based on averaging converges to an equilibrium such iterations have the interpretation that every firm responds to the average of sales by other firms in brevious periods

perturbed adaptive dynamics in coalition form games abstract players adaptively learn how to bargain a characteristic function describes the available surplus the underlying bargaining game extends the nash demand game by allowing subcoalitions to reach an agreement players demands must be multiples of a money unit we show that stochastically stable allocations ssa i e allocations that are most stable to unlikely errors are a subset of the core uniqueness does not obtain even when the money unit becomes arbitrarily small nonetheless every ssa is related to the allocation that maximizes the product of players utilities over the core i e constrained egalitarian solution for tu games journal of economic literature classification numbers c71 c72 c78

adaptive play in multiplayer bargaining situations we study the dual issues of allocation and coalition formation in a model of social learning for a class of economies which can be expressed in terms of a real valued characteristic function we first show that all self perpetuating allocations realized from a simple bargaining game must be core allocations although players make simultaneous demands for surplus and only on their own behalf following this we provide a sufficient condition under which the society eventually learns to divide the surplus according to some core allocation regardless of the initial history

learning information and sorting in market entry games theory and evidence previous data from experiments on market entry games n player games where each player faces a choice between entering a market and staying out appear inconsistent with either mixed or pure nash equilibria here we show that in this class of game learning theory predicts sorting that is in the long run agents play a pure strategy equilibrium with some agents permanently in the market and some permanently out we conduct experiments with a larger number of repetitions than in previous work in order to test this prediction we find that when subjects are given minimal information only after close to 100 periods do subjects begin to approach equilibrium in contrast with full information subjects learn to play a pure strategy equilibrium relatively quickly however the information which permits rapid convergence revelation of the individual play of all opponents

credit crises precautionary savings and the liquidity trap we use a model a la bewly huggett ayagari to explore the eects of a credit crunch on consumer spending households borrow and lend to smooth idiosyncratic income shocks facing an exogenous borrowing constraint we look at the economy response after an unexpected permananent tightening of this constraint the interest rate drops sharply in the short run and then adjusts to a lower steady state level this is due to the fact that after the shock a large fraction of agents is far below their target holdings of precautionary savings and this generates a large temporary positive shock to net lending we then look at the eects on output here two opposing forces are present as households can deleverage in two ways by consuming less and by working more we show that under a reasonable parametrization the eect on consumer spending dominates and precautionary behavior generates a recession if we add nominal rigidities two things happen i supply side responses are muted and ii there is a lower bound on the interest rate adjustment these two elements tend to amplify the recession caused by the credit tightening

a dynamic model of housing demand estimation and policy implications a dynamic model of housing demand using data from the panel study of income dynamics psid we specify estimate and simulate a dynamic structural model of housing demand our model generalizes previous applied econometric work by incorporating realistic features of the housing market including non convex adjustment costs from buying and selling a home credit constraints from minimum downpayment requirements and uncertainty about the evolution of incomes and home prices we argue that these features are critical for capturing salient features of housing demand observed in the psid after estimating the model we use it to simulate how consumer behavior responds to house price and income declines as well as tightening credit these experiments are motivated by the u s recession starting in december of 2007 that saw large falls in home prices large negative income shocks for many households and tightening credit standards in the short run relatively few households adjust their housing stock households respond instead by reducing non housing consumption and reducing wealth because they wish to avoid losing their home and the associated adjustment costs households that adjust in the short run are those hit with a series of bad shocks such as a negative income shock and a home price decline a larger proportion of households do adjust their consumption in the long run increasing their housing stock since housing is less expensive however such changes may occur several years after the shocks listed above

fictitious play property of the nash demand game we show that the nash demand game has the fictitious play property we also show that almost every fictitious play process and its associated belief path converge to a pure strategy nash equilibrium in the nash demand game

economists models of learning abstract economic theorists have intensively studied learning in games and decisions over the last decade this essay puts some of the work in perspective and offers opinions about what still needs to be learned journal of economic literature classification numbers c73 d83

commitment and conflict in bilateral bargaining building on crawford 1982 we study a model of bilateral bargaining in which negotiators can make binding commitments at a low positive cost c our primary solution concept is iterated strict dominance if commitment attempts never fail there are three solutions in two solutions all the surplus goes to one player in the third solution there is a high probility of con ict if commitment attempts succeed with probability q 1 the unique solution entails con ict with probability q 2 when c 0 analogous results hold if the requirement of iterated strict dominance is replaced by iterated weak dominance

credit booms and lending standards evidence from the subprime mortgage market this paper links the u s subprime mortgage crisis to demand side factors that contributed to the rapid expansion of the u s mortgage market we show that denial rates were relatively lower in areas that experienced faster credit demand growth and that lenders in these high growth areas attached less weight to applicants loan to income ratios the results are robust to controlling for supply side factors including house price appreciation mortgage securitization and other economic fundamentals and to several robustness tests controlling for endogeneity the results are consistent with the notion that a relaxation of lending standards triggered by an increased demand for loans contributed to the boom and the ensuing crisis together with other supply side explanations these findings shed new light on the relationship between credit booms and financial instability

evolutionary game theory game theory has been developed as a theory of rational behavior in interpersonal conflict situations with economics and the other social sciences being the intended fields of application since the theory is based on an idealized picture of human rationality it is by no means obvious that it can be applied to situations in which the players cannot be attributed any intellectual capabilities however in their seminal paper the logic of animal conflict maynard smith and price showed that animal contests can be modeled as games and that game theory can be applied successfully in biology the objective of this chapter is to review some of the developments in this biological branch of game theory and to point out the distinctions and similarities with the classical branch also see parker and hammerstein 1985 the main emphasis will be on the mathematics involved lack of space prevents an extensive discussion of the underlying biological assumptions as well as an analysis of specific examples for these the reader is referred to the very stimulating book evolution and the theory of games by john maynard smith

learning in games with unstable equilibria we propose a new concept for the analysis of games the tasp which gives a precise prediction about non equilibrium play in games whose nash equilibria are mixed and are unstable under fictitious play like learning we show that when players learn using weighted stochastic fictitious play and so place greater weight on recent experience the time average of play often converges in these unstable games even while mixed strategies and beliefs continue to cycle this time average the tasp is related to the cycle identified by shapley l s shapley some topics in two person games in m dresher et al eds advances in game theory princeton university press princeton 1964 the tasp can be close to or quite distinct from nash equilibrium

commentary john nash and evolutionary game theory abstract john nash s work laid the foundations for evolutionary game theory as well as the theory of games with rational agents the nash bargaining solution emerges as a natural solution concept in both of these settings

the great recession lessons from microeconomic data crises and sharp economic downturns while undesirable provide economists with a unique opportunity to test and hone economic theory indeed some of the most influential advance ments in economic thought including milton friedman s monetarist tradition john maynard keynes fiscal theory and irving fisher s debtdeflation hypothesis emerged from analysis of the great depression the current economic malaise which we refer to as the great recession provides another watershed moment to reevaluate our core economic beliefs however in contrast to our peers in previous crises we are fortunate to have access to large scale microeconomic datasets and advancements in computational capacity these advantages allow for a more rigorous analysis of the current recession and therefore a more informed understanding of its origins propagation and consequences our purpose is to highlight how a micro level analysis of the great recession provides us with important clues to understand the origins of the crisis the link between credit and asset prices the feedback effect from asset prices to the real economy and the role of household leverage in explaining the downturn we hope that our discussion also serves as an example of the useful ness of incorporating microeconomic data and techniques in answering traditional macroeco nomic questions i what were the origins of the credit cycle credit demand or credit supply

learning to be fair abstract we study the process of equilibrium selection in games when players have social preferences of the type discussed among others by rabin 1993 and segal and sobel 2007 to this end we employ a standard noisy version of the best response dynamics we obtain several results concerning some popular games such as the prisoner s dilemma and the battle of the sexes we show that reciprocity may have a negative effect on the equilibrium selection process when players are sufficiently concerned with reciprocity the stochastically stable equilibrium in the battle of the sexes is inefficient at the same time the cooperative equilibrium in the prisoner s dilemma is never stochastically stable

monetary policy when households have debt new evidence on the transmission mechanism in response to an unanticipated change in interest rates households with mortgage debt adjust their expenditure signicantly especially on durable goods renters react to a lesser extent and outright home owners do not react at all all housing tenure groups experience a signicant change in disposable income over and above the direct impact on mortgage repayments the response of house prices is sizable driving a signicant adjustment in loanto income ratios but little change in loan to value ratios a simple collateral constraint model augmented with durable goods and a renting decision generates predictions consistent with these novel empirical ndings and suggests that heterogeneity in housing debt positions plays an important role in the transmission of monetary policy

global banks and crisis transmission abstract we study the effect of financial integration through banks on the transmission of international business cycles in a sample of 18 20 developed countries between 1978 and 2009 we find that in periods without financial crises increases in bilateral banking linkages are associated with more divergent output cycles this relation is significantly weaker during financial turmoil periods suggesting that financial crises induce co movement among more financially integrated countries we also show that countries with stronger direct and indirect financial ties to the u s experienced more synchronized cycles with the u s during the recent 2007 2009 crisis we then interpret these findings using a simple general equilibrium model of international business cycles with banks and shocks to banking activity the model suggests that the relation between integration and synchronization depends on the type of shocks hitting the world economy and that shocks to global banks played an important role in triggering and spreading the 2007 2009 crisis

stochastic adaptation in finite games played by heterogeneous populations we analyze stochastic adaptation in finite n player games played by heterogeneous populations containing best repliers better repliers and imitators individuals select strategies by applying a

learning to like what you have explaining the endowment effect the endowment effect describes the fact that people demand much more to give up an object than they are willing to spend to acquire it the existence of this effect has been documented in numerous experiments we attempt to explain this effect by showing that evolution favors individuals whose preferences embody an endowment effect the reason is that an endowment effect improves one s bargaining position in bilateral trades we show that for a general class of evolutionary processes strictly positive endowment effects will survive in the long run

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

the economics of convention c onventions regulate much of economic and social life yet they have received surprisingly little attention from economists by a convention we mean a pattern of behavior that is customary expected and self enforcing everyone conforms everyone expects others to conform and everyone has good reason to conform because conforming is in each person s best interest when everyone else plans to conform lewis 1969 familiar examples include following rules of the road adhering to conventional codes of dress and using words with their conventional meanings conventions with direct economic implications include species of money and credit industrial and technological standards accounting rules and forms of economic contracts indeed it would scarcely be an exaggeration to say that almost all economic and social institutions are governed to some extent by convention the main feature of a convention is that out of a host of conceivable choices only one is actually used this fact also explains why conventions are needed they resolve problems of indeterminacy in interactions that have multiple equilibria indeed from a formal point of view we may define a convention as an equilibrium that everyone expects in interactions that have more than one equilibrium the economic significance of conventions is that they reduce transaction costs imagine the inconvenience if whenever two vehicles approached one another the important exceptions are sugden 1986 and ullman margalit 1977 the interested reader might also refer to the symposium on social norms that appeared in the fall 1989 issue of this journal with articles by sugden 1989 and elster 1989

intergenerational redistribution in the great recession in this paper we construct a stochastic overlapping generations general equilibrium model in which households are subject to aggregate shocks that aect both wages and asset prices we use a calibrated version of the model to quantify how the welfare costs of severe recessions are distributed across dierent household age groups the model predicts that younger cohorts fare better than older cohorts when the equilibrium decline in asset prices is large relative to the decline in wages asset price declines hurt the old who rely on asset sales to nance consumption but benet the young who purchase assets at depressed prices in our preferred calibration asset prices decline more than twice as much as wages consistent with the experience of the us economy in the great recession a model recession is approximately welfare neutral for households in the 20 29 age group but translates into a large welfare loss of around 10 percent of lifetime consumption for households aged 70 and over

efficiency risk aversion and portfolio insurance an analysis of financial asset portfolios held by investors in the united kingdom using data for the united kingdom the author shows that investors in six different wealth ranges hold mean variance efficient portfolios of financial assets this result permits him to estimate coefficients of relative risk aversion for investors in each wealth range the author finds that these coefficients are much higher than most previous studies have found this implies that investors 1 are unwilling to hold risky assets unless they are compensated with a sufficiently high risk premium and 2 are willing to pay for portfolio insurance the general nonavailability of portfolio insurance in the united kingdom appears to indicate a supply side rather than a demand side failure copyright 1996 by royal economic society

stationary equilibria in asset pricing models with incomplete markets and collateral we consider an infinite horizon exchange economy with incomplete markets and collateral constraints as in the two period model of geanakoplos and zame 2002 households can default on their liabilities at any time and financial securities are only traded if the promises associated with these securities are backed by collateral we examine an economy with a single perishable consumption good where the only collateral available consists of productive assets in this model competitive equilibria always exist and we show that under the assumption that all exogenous variables follow a markov chain there also exist stationary equilibria these equilibria can be characterized by a mapping from the exogenous shock and the current distribution of financial wealth to prices and portfolio choices we develop an algorithm to approximate this mapping numerically and discuss ways to implement the algorithm in practice a computational example demonstrates the performance of the algorithm and shows some quantitative features of equilibria in a model with collateral and default

on modeling and interpreting the economics of catastrophic climate change with climate change as prototype example this paper analyzes the implications of structural uncertainty for the economics of low probability high impact catastrophes even when updated by bayesian learning uncertain structural parameters induce a critical tail fattening of posterior predictive distributions such fattened tails have strong im plications for situations like climate change where a catastrophe is theoretically possible because prior knowledge cannot place sufficiently narrow bounds on overall damages this paper shows that the economic consequences of fat tailed structural uncertainty along with unsureness about high temperature damages can readily outweigh the effects of discounting in climate change policy analysis

lloyd shapley s matching and game theory this is a survey of lloyd shapley s contributions to matching theory and game theory in general starting with the work that inspired the swedish academy to award the 2012 nobel memorial prize in economic sciences to lloyd shapley and alvin roth