A Suggested Interpretation of Some Experimental Results on Preplay Communication

M. Rabin (1994, J. Econ. Theory63, 370-391) proposes a model of behavior in two-person complete-information games with preplay communication, using non-equilibrium notions in the spirit of rationalizability to derive lower bounds on players' expected payoffs when players have unlimited communication opportunities. This paper adapts Rabin's model so that it can be used to analyze the results of the experiments of R. Cooper et al. (1989, Rand J. Econ.20, 568-587) on structured preplay communication in the Battle of the Sexes and the results of the unstructured bargaining experiments of Roth, Malouf, and Murnighan. Adding empirically motivated restrictions that allow the model to predict the payoff effects of changes in bounded communication possibilities like those in the experiments, it is shown that the data from both experiments are generally consistent with Rabin's model, and with the predictions of the extended model. Journal of Economic Literature Classification Numbers: C70, C72, C78, C91.     

An Experimental Study of Communication and Coordination in Noncooperative Games

This paper reports the results of an experiment designed to test the usefulness of alternative solution concepts to explain players' behavior in noncooperative games with preplay communication. In the experiment subjects communicate byplain conversationprior to playing a simple game. In this setting, we find that the presumption ofindividualisticandindependentbehavior underlying the concept of Nash equilibrium is inappropriate. Instead, we observe behavior to becoordinatedandcorrelated. Statistical tests reject Nash equilibrium as an explanation of observed play. The coalition proof correlated equilibrium of the game, however, explains the data when the possibility of errors by players is introduced.Journal of Economic LiteratureClassification Numbers: C72, C92.     

On equilibrium in Hart's securities exchange model

In this paper, we use a no unbounded arbitrage condition to give a very direct proof of the existence of equilibrium in Hart's unbounded securities exchange model (J. Econ. Theory, 9 (1974), 293–311). We also examine the relationship between the no unbounded arbitrage condition and the sufficiency conditions of Hart, ibid. and Hammond (J, Econ. Theory, 31 (1983), 170–175). We present an example to show that if traders are not sufficiently risk averse, then Hammond's overlapping expectations condition is not, in general, equivalent to the no unbounded arbitrage condition or Hart's sufficiency conditions, and therefore, is not sufficient to guarantee the existence of equilibrium. We also present an example to show that it is possible for the no unbounded arbitrage condition to hold without overlapping expectations, and therefore, it is possible for equilibrium to exist without overlapping expectations.     

The Phillips Curve and Optimal Policy in a Structural Signal Extraction Model

We study a monetary economy subject to “signal extraction” problems, and investigate within that framework the positive and normative aspects of monetary policy. As in Lucas (1972, Journal of Economic Theory,4, 103–124; 1973, American Economic Review, 63, 326–334), imperfect signal perception generates macroeconomic correlations similar to those found in the “Phillips curve” literature. Moving to normative aspects, we find that, when aggregate shocks are present, traditional nonactivist policies do not permit reaching the first best, and that an intelligent activist policy always leads to better outcomes. The specific characteristics and effectiveness of this optimal policy also depend crucially on the problem of signal extraction. Journal of Economic Literature Classification Number: E5.     

Let׳s talk it over: Coordination via preplay communication with level-k thinking

This paper reconsiders Farrell׳s (1987) and Rabin׳s (1994) analyses of coordination via preplay communication, focusing on Farrell׳s analysis of Battle of the Sexes. Replacing their equilibrium and rationalizability assumptions with a structural non-equilibrium model based on level-k thinking, I reevaluate Farrell and Rabin׳s assumptions on how players use language and their conclusions on the limits of communication in bringing about coordination. The analysis partly supports their assumptions about how players use language, but suggests that their “agreements” do not reflect a full meeting of the minds. A level-k analysis also yields very different conclusions about the effectiveness of communication.     

Evolutionary Learning in Signalling Games

We study equilibrium selection by evolutionary learning in monotone two-type signalling games. The learning process we study extends that introduced by Young (1993, Econometrica61, 57–84) to deal with incomplete information and sequential moves; it thus involves stochastic trembles. For vanishing trembles the process gives rise to strong selection among sequential equilibria: if the game has separating equilibria, then in the long run only play according to the so-called Riley equilibrium will be observed frequently. Journal of Economic Literature Classification Number: C72.     

Harmful lie aversion and lie discovery in noisy expert advice games

This study tests whether individuals are reluctant to tell lies, or perhaps only “harmful lies”, in a previously untested environment: an expert sending a message to a decision maker whose interpretation of that message is subject to error, i.e. a noisy sender–receiver game. In the Aligned treatment, the expert can send a “white lie” to the receiver, eliminating the negative effects of noise and improving both parties’ payoffs. In the Conflict treatment, lies are harmful and the inability to commit to truthtelling destroys all meaningful communication in equilibrium unless there is a cost of lying. In the experiment, receivers are overly trusting and experts learn to take advantage of this. As experts gain experience they tell stronger and more frequent lies in both treatments, consistent with models of reinforcement learning. The findings suggest that neither harmful nor universal lie aversion is a factor when communication is noisy, provided individuals have time to discover their personal benefits of lies.     

Hedonic prices and cost/benefit analysis

Hedonic prices have been used to evaluate the willingness to pay for attributes. We reformulate the notion of hedonic price from a composite price on housing to a unit price on traded quantities, in conformity with long run competitive equilibrium theory. This formulation was suggested (but not developed) by Rosen (J. Polit. Econ.82, No. 1 (1974), 34–35). By first characterizing an efficient allocation of consumers to space, we show that hedonic unit prices can be understood as a bid-rent function which supports the efficient allocation. This is despite the fact that the lots over which consumers bid are themselves endogenous. We show that unit hedonic prices reveal preferences in a manner different from composite hedonic expenditures.     

Pre-play communication with forgone costly messages: experimental evidence on forward induction

We experimentally study optional costly communication in Stag-Hunt games. Prior research demonstrates that efficient coordination is difficult without a communication option but obtains regularly with mandatory costless pre-play messages. We find that even small communication costs dramatically reduce message use when communication is optional, but efficient coordination can occur with similar frequency as under costless communication. These findings can be accounted for by formalizations of forward induction that take Nash equilibrium as a reference point (such as Kohlberg and Mertens in Econometrica 54: 1003–1037, 1986; Govindan and Wilson in Econometrica 77: 1–28, 2009), while formalizations that only appeal to (higher-order) knowledge of rationality remain silent in this environment.     

The communication requirements of social choice rules and supporting budget sets

The paper examines the communication requirements of social choice rules when the (sincere) agents privately know their preferences. It shows that for a large class of choice rules, any minimally informative way to verify that a given alternative is in the choice rule is by verifying a “budget equilibrium”, i.e., that the alternative is optimal to each agent within a “budget set” given to him. Therefore, any communication mechanism realizing the choice rule must find a supporting budget equilibrium. We characterize the class of choice rules that have this property. Furthermore, for any rule from the class, we characterize the minimally informative messages (budget equilibria) verifying it. This characterization is used to identify the amount of communication needed to realize a choice rule, measured with the number of transmitted bits or real variables. Applications include efficiency in convex economies, exact or approximate surplus maximization in combinatorial auctions, the core in indivisible-good economies, and stable many-to-one matchings.     

Free access vs private ownership: A comparison

Weitzman (J. Econ. Theory8 (1974), 225–234) has established that under free access properties of average or better quality will be overutilised relative to the efficient private property equilibrium. This leaves open the question of what happens to the low quality properties. It is shown here that there are conflicting considerations and the outcome is ambigous. Necessary and sufficient conditions are obtained for less of a variable input to be attracted to a site when access is free than when a private owner makes a charge for access.     

Perfect communication equilibria in repeated games with imperfect monitoring

This paper introduces an equilibrium concept called perfect communication equilibrium for repeated games with imperfect private monitoring. This concept is a refinement of Myerson's [Myerson, R.B., 1982. Optimal coordination mechanisms in generalized principal agent problems, J. Math. Econ. 10, 67–81] communication equilibrium. A communication equilibrium is perfect if it induces a communication equilibrium of the continuation game, after every history of messages of the mediator. We provide a characterization of the set of corresponding equilibrium payoffs and derive a Folk Theorem for discounted repeated games with imperfect private monitoring.     

Racism and redistribution in the United States: A solution to the problem of American exceptionalism

The two main political parties in the United States in the period 1976–1992 put forth policies on redistribution and on issues pertaining directly to race. We argue that redistributive politics in the US can be fully understood only by taking account of the interconnection between these issues in political competition. We identify two mechanisms through which racism among American voters decreases the degree of redistribution that would otherwise obtain. In common with others, we suggest that voter racism decreases the degree of redistribution due to an anti-solidarity effect: that (some) voters oppose government transfer payments to minorities whom they view as undeserving. We suggest a second effect as well: that some voters who desire redistribution nevertheless vote for the anti-redistributive (Republican) party because its position on the race issue is more consonant with their own, and this, too, decreases the degree of redistribution in political equilibrium. This we name the policy bundle effect. We propose a formal model of multi-dimensional political competition that enables us to estimate the magnitude of these two effects, and estimate the model for the period in question. We compute that voter racism reduced the income tax rate by 11–18% points; the total effect decomposes about equally into the two sub-effects. We also find that the Democratic vote share is 5–38% points lower than it would have been, absent racism. The magnitude of this effect would seem to explain the difference between the sizes of the public sector in the US and northern European countries.     

Job Matching and Coalition Formation with Utility or Disutility of Co-workers

This paper studies the job matching market in Kelso and Crawford (1982), Econometrica50, 1483–1504, with one exception, that co-workers may generate utility or disutility in the workplace. We provide a simple idea to show how a great number of sufficient conditions for a nonempty core in the literature can be extended to this labor market. A generalized competitive equilibrium with a tax/subsidy system is also discussed. Journal of Economic Literature Classification Number: D71.     

Symmetric Separating Equilibria in English Auctions

We characterize the set of perfect Bayesian equilibria in symmetric separating strategies in the model of English auctions given by P. R. Milgrom and R. J. Weber (1982, Econometrica50, 1089–1122). There is a continuum of such equilibria. The equilibrium derived by Milgrom and Weber is that in which bids are maximal. Only in the case of pure private values does a restriction to weakly undominated strategies select a unique equilibrium. This has important implications for empirical studies of English auctions, particularly outside the pure private values paradigm. Journal of Economic Literature Classification Numbers: D44, D82.     

Output gains from accelerating core inflation

Previous research finds that the analysis of sacrifice ratios–namely, identifying disinflation episodes, calculating the sacrifice ratio, and looking at its determinants–changes substantially when one moves from headline to core inflation. This paper examines whether similar findings are obtained when examining benefice ratios, and we find arguably even greater differences. Specifically, we see that headline inflation identifies far more inflationary episodes since the 1990s than core inflation does. Furthermore, Jordan’s (1997) argument that the speed of inflation is a negative and significant determinant of benefice ratios does not hold when we move from headline to core inflation, both within the U.S. and also across the OECD. We also find strong evidence that the initial level of GDP at the onset of an inflationary episode matters. In particular, output gains from accelerating inflation appear only to be beneficial for OECD countries that start with a low level of GDP. Conversely, countries that start with a high level of GDP should not pursue additional output gains from allowing a rise in inflation.     

The value of rents and the likelihood of conflicts

This paper extends the prey–predator model of Grossman and Kim (J Political Econ 103:1275–1288, 1995) to analyze the relation between the value of a contested rent and the emergence of conflict. We show that an increase in the value of the rent makes a conflict equilibrium more likely. We also analyze the case where the valuation of the rent is different for the two players. We find, for example, that a conflict equilibrium may occur even though the predator has an important disadvantage in warfare. That is when his valuation of the rent is sufficiently high compared to that of the prey.

The Perils of Taylor Rules

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.     

Capital as a commitment: Strategic investment to deter mobility

This paper analyzes how an early entrant in a market can exploit its head start by strategic investment. The analysis is based on Spence's paper, Investment strategy and growth in a new market, (Bell J. Econ., 10 (1979), 1–19). We frist study the investment game in the no-discounting case, which embodies the key features of mobility deterrence. We establish the existence of a set of perfect equilibria and suggest that one particular equilibrium is most reasonable. This equilibrium, also valid with discounting, involves the follower firm being forever deterred from investing to its steady-state reaction curve, in contrast to Spence's proposed solution.     

Coordination in Oligopoly

The private and social efficiency of two "behavioral" coordination mechanisms is examined in this paper. In Cournot oligopoly, firms prefer immediate coordination on the Nash equilibrium (interpreted as a preplay communication) over the best-reply dynamics (and fictitous play) which converge to the equilibrium, but with delay (interpreted as a decentralized learning process). In Bertrand oligopoly, firms prefer the learning process. These results indicate that firms have incentives to create institutions, such as trade associations or informal meetings, to facilitate coordination of production capacities, but not prices. Moreover, quantity agreements may even increase social welfare.