COGNITIVE EMPATHY IN CONFLICT SITUATIONS

Two individuals are involved in a conflict situation in which preferences are ex ante uncertain. Although they eventually learn their own preferences, they have to pay a small cost if they want to secretly learn their opponent's preferences. We show that there is an interval with an upper bound less than 1 and lower bound greater than zero such that, for sufficiently small positive costs of information acquisition, in any Bayesian Nash equilibrium of the resulting game of incomplete information the probability of acquiring information about the opponent's preferences is within this interval.     

The optimality of nominal contracts

Summary. This paper presents a model in which agents choose to use money as a medium of exchange, a means of payment, and a unit of account. The paper defines conditions under which nominal contracts, promising future payment of a fixed number of units of fiat money, prove to be the optimal contract form in the presence of either relative or aggregate price risk. When relative prices are random, nominal contracts are optimal if individuals have ex ante similar preferences over future consumption. When the aggregate price level is random, whether from shocks to the money supply or aggregate output, nominal contracts (perhaps coupled with equity contracts) lead to optimal risk-sharing if individuals have the same degree of relative risk aversion. Finally, nominal contracts may be optimal if the repayment of contracts is subject to a binding cash-in-advance constraint. In this case, a contingent contract increases the risk of holding excessive cash balances. Received: March 29, 1996; revised version: February 25, 1997     

The separability axiom and equal-sharing methods

A quasi-linear social choice problem is defined as selecting one (among finitely many) indivisible public decision and a vector of monetary transfers among agents to cover the cost of this decision. This decision is based upon individual preferences, which are assumed to be additively separable and linear in money. The Separability axiom is a consistency property for choice methods on societies with variable size: the decision is not affected if we remove an arbitrary agent under the condition that he be guaranteed his original utility level and the cost to the remaining agents is modified accordingly. Thus the utility level assigned by the social choice function to agent i is the price at which the other agents are unanimously willing to buy agent is share of the decision power. A general characterization of choice methods satisfying this axiom is provided. Three subclasses of particular interest are characterized by additional milder axioms. Those are: (i) equal sharing of the surplus left over some reference utility (e.g., the utility at a status quo decision), (ii) utilitarian methods that merely select the efficient public decision and perform no monetary transfers, and (iii) equal allocation of nonseparable costs, which divides equally the surplus left over from the utility derived from the pivotal mechanism (also known as the Vickrey-Clarke-Groves mechanism).     

Are incentives against economic justice?

We consider the problem of fairly allocating a social endowment of indivisible goods and money when the domain of admissible preferences contains, but is not restricted to, quasi-linear preferences. We analyze the manipulability of the Generalized Money Rawlsian Fair (GMRF) solutions. (i) We show that the Nash and strong Nash equilibrium correspondences of the “preference revelation game form” associated with each GMRF solution coincide with the no-envy solution (in equilibrium, efficiency is preserved according to agents' true preferences). (ii) A corollary is that the GMRF solutions “naturally implement” the no-envy solution in Nash and strong Nash equilibria.     

Population Monotonicity and Egalitarianism for Binary Social Choice Problems

We consider the class of binary social choice problems. A society must choose one of two public projects, money being available to perform side payments and each agent having quasi-linear preferences. Moulin (1987, Quarterly Journal of Economics 102 , 769–783) formulates the problem and characterizes the egalitarian solution on the basis of agreement . This axiom requires that changes in the preferences of some members of the society should affect the agents whose preferences have not changed in the same direction; all gain or all lose. In this paper, we present an alternative characterization of the egalitarian solution on the basis of population monotonicity. This axiom requires that upon the arrival of new agents, all of the original agents should be affected in the same direction; all gain or all lose.     

Coalitional strategy-proofness and fairness

This paper considers the problem of assigning a finite number of indivisible objects, like jobs, houses, positions, etc., to the same number of individuals. There is also a divisible good (money) and the individuals consume money and one object each. The class of fair allocation rules that are strategy-proof in the strong sense that no coalition of individuals can improve the allocation for all of its members, by misrepresenting their preferences, is characterized. It turns out that given a regularity condition, the outcome of a fair and coalitionally strategy-proof allocation rule must maximize the use of money subject to upper quantity bounds determined by the allocation rule. If available money is nonnegative, objects may be jobs and the distribution of money a wage structure. If available money is negative, the formal model may reflect a multi-object auction. In both cases fairness means equilibrium, i.e., that each individual receives a most demanded object. I would like to thank Tommy Andersson, Bo Larsson, Zaifu Yang and the participants of the seminars in Copenhagen and Lund for helpful comments on this paper. I will also thank an anonymous referee for very valuable comments. Financial support from The Jan Wallander and Tom Hedelius Foundation is gratefully acknowledged.     

Financing Public Goods by Means of Lotteries

When viewed as taxes, lotteries are routinely criticized as being both inequitable and inefficient. But is this an entirely fair comparison? Frequently lotteries are used in lieu of voluntary contributions by private charities and governments when taxes are not feasible. When heterogeneous individuals with quasi-linear preferences participate in lotteries whose proceeds will be used to fund a public good, we find that, relative to voluntary contributions, wagers in the unique lottery equilibrium (a) increase the provision of the public good, (b) are welfare improving, and (c) provide levels of the public good close to first-best as the lottery prize increases.     

A Signaling Model of Multiple Currencies

In this paper, we demonstrate that it may be socially optimal for countries to have different currencies, even though they have no possibility of independently controlling their money supplies. We assume that agents have heterogeneous preferences over goods of different national origin, and that these preferences are private information. We prove three results. First, for a range of parameters, it is optimal for different countries to have different currencies so that buyers can more efficiently signal their preferences over goods to sellers. Second, if it is socially optimal to have different national currencies, then it is socially optimal for sellers to sell lower quantities to buyers bearing foreign currency. Finally, it is only necessary to have two monies if cross-country trade is optimal.Journal of Economic LiteratureClassification Number: F33     

Sharing a River

A group of agents located along a river have quasi-linear preferences over water and money. We ask how the water should be allocated and what money transfers should be performed. The core lower bounds require that no coalition should get less than the welfare it could achieve by using the water it controls. The aspiration upper bounds demand that no coalition enjoy a welfare higher than what it could achieve in the absence of the remaining agents. Exactly one welfare distribution satisfies the core lower bounds and the aspiration upper bounds: it is the marginal contribution vector corresponding to the ordering of the agents along the river. Journal of Economic Literature Classification Numbers: D62, C71.     

Is it my money or not? An experiment on risk aversion and the house-money effect

The house-money effect, understood as people’s tendency to be more daring with easily-gotten money, is a behavioral pattern that poses questions about the external validity of experiments in economics: to what extent do people behave in experiments like they would have in a real-life situation, given that they play with easily-gotten house money? We ran an economic experiment with 122 students to measure the house-money effect on their risk preferences. They received an amount of money with which they made risky decisions involving losses and gains; a randomly selected treatment group received the money 21 days in advance and a control group got it the day of the experiment. From a simple calculation we found that participants in the treatment group only spent on average approximately 35 % of their cash in advance. The data confirms the well documented results that men are more tolerant to risk than women, and that individuals in general are more risk tolerant towards losses than towards gains. With our preferred specification, we find a mean CRRA risk aversion coefficient of 0.34, with a standard deviation of 0.09. Furthermore, if subjects in the treatment group spent 35 % of the endowment their CRRA risk aversion coefficient is higher than that of the control group by approximately 0.3 standard deviations. We interpret this result as evidence of a small and indirect house money effect operating though the amount of the cash in advance that was actually spent. We conclude that the house money effect may play a small role in decisions under uncertainty, especially when involving losses. Our novel design, however, could be used for other domains of decision making both in the lab and for calibration of economic models used in micro and macroeconomics.     

General equilibrium with nonconvexities and money

In a general-equilibrium economy with nonconvexities, there are sunspot equilibria with good welfare properties; sunspots can ameliorate the effects of the nonconvexities. For these economies, we show that agents act as if they have quasi-linear utility functions. We use this result to construct a new model of monetary exchange along the lines of Lagos and Wright, where trade occurs in both centralized and decentralized markets, but instead of quasi-linear preferences we assume general preferences but with indivisible labor. This suggests that modern monetary theory is more robust than one might have thought. It also constitutes progress on the classic problem of integrating monetary economics and general-equilibrium theory.     

Incomplete preferences and rational intransitivity of choice

Do violations of classical rationality theory imply that agents are acting against their self-interest? To answer this question, we investigate whether completeness and transitivity necessarily hold when agents choose outcome rationally—that is, their choice sequences do not lead to dominated outcomes. We show that, because of the danger of money pumps and other manipulations, outcome rationality implies that agents must have transitive psychological preferences. Revealed preferences, on the other hand, must be complete since agents can be forced to choose from any set of options. But these justifications of transitivity and completeness cannot be combined. We show that if psychological preferences are incomplete then revealed preferences can be intransitive without exposing agents to manipulations or violating outcome rationality. We also show that a specific case of nonstandard behavior, status quo maintenance, is outcome-rational in the simple environments considered in the experimental literature, but not in more complex settings.     

Whose money is it anyway? Using prepaid incentives in experimental economics to create a natural environment

Simulating a real world environment is of utmost importance for achieving accurate and meaningful results in experimental economics. Offering monetary incentives is a common method of creating this environment. In general, experimenters provide the rewards at the time of experiment. In this paper, we argue that receiving the reward at the time of the experiment may lead participants to make decisions as if the money they are using were not their own. To solve this problem, we devised a “prepaid mechanism” that encourages participants to use the money as if it were their own.     

Betting on weight loss … and losing: personal gambles as commitment mechanisms

Professional bookmakers rarely accept bets from individuals who directly control the outcome of the bet. We analyse a unique exception to this rule and a potential policy innovation in the battle against obesity: a weight loss betting market. If obese individuals have time-inconsistent preferences then commitment mechanisms, such as personal gambles, should help them restrain their short-term impulses and lose weight. Correspondence with the bettors confirms that this is their primary motivation. However, it appears that the bettors in our sample are not particularly skilled at choosing effective commitment mechanisms. Despite payoffs of as high as $7350, approximately 80% of people who spend money to bet on their own behaviour end up losing their bets. Empirical analysis of the betting market yields further insights. Males are treated very differently compared to females: being male is considered equivalent to having an extra 6 months to lose the same amount of weight. Movements in the market price also confirm the belief that rigidity is preferred to flexibility in setting successful weight loss targets.     

A STABLE NASH MECHANISM FOR QUASI-ADDITIVE PUBLIC-GOOD ENVIRONMENTS*

In this paper we present a simple game form implementing Lindahl allocations as Nash equilibrium outcomes, which has nice stability properties. we show that if the preferences of eaach consumer are representable by a utility function of the form a(y)x_i+b_i(y), where x_i(y), where x_i is the amount of private good and y, the amount of public good, then the Nash equilibrium of our geme is locally stable under the gradient adjustment process. This restriction on the preferences has been known in hte literature as the necessary and sufficient condition for the Pareto optimal amount of pukic goods to be independent of the private goods distribution. This type of preference includes quasi-linear preferences as a special case. but unlike quasi-linearity, this allows a non zero income effect of demand for public goods as well as private goods, which is often supported by empirical evidence. Our result shows how an equilbirium can be achieved over time by a decentralized strategy adjustement process for a fairly general class of environments, even in the absence of a dominant-strategy equilibrium.     

Matching soulmates

We study iterated matching of soulmates (IMS), a recursive process of forming coalitions that are mutually preferred by members to any other coalition containing individuals as yet unmatched by this process. If all players can be matched this way, preferences are IMS-complete. A mechanism is a soulmate mechanism if it allows the formation of all soulmate coalitions. Our model follows Banerjee, Konishi, and Sönmez, except reported preferences are strategic variables. We investigate the incentive and stability properties of soulmate mechanisms. In contrast to prior literature, we do not impose conditions that ensure IMS-completeness. A fundamental result is that, (1) any group of players who could change their reported preferences and mutually benefit does not contain any players who were matched as soulmates and reported their preferences truthfully. As corollaries, (2) for any IMS-complete profile, soulmate mechanisms have a truthful strong Nash equilibrium, and (3) as long as all players matched as soulmates report their preferences truthfully, there is no incentive for any to deviate. Moreover, (4) soulmate coalitions are invariant core coalitions—that is, any soulmate coalition will be a coalition in every outcome in the core. To accompany our theoretical results, we present real-world data analysis and simulations that highlight the prevalence of situations in which many, but not all, players can be matched as soulmates. In the Appendix we relate IMS to other well-known coalition formation processes.     

Tiebout and redistribution in a model of residential and political choice

The paper considers a two-community model with freely mobile individuals. Individuals differ not only in their incomes, but also in their tastes for a local public good. In each jurisdiction, the amount of public services is determined by majority vote of the inhabitants, and local spending is financed by a residence-based linear income tax. When making their residential and political choices, individuals thus face a trade-off between the provisionary and redistributive effects of policies. We analyze this trade-off and show that Tiebout-like sorting equilibria often exist. If the spread in tastes among individuals is very large, an almost perfect sorting according to preferences emerges; otherwise, a partial sorting prevails and stratification into rich and poor communities is more pronounced. Importantly, we demonstrate that all these sorting equilibria exist whether or not individuals are allowed to relocate after voting.     

Coalitional manipulation and the Pareto rule

This paper examines aggregation procedures that map profiles of individual preferences into choice sets. An aggregation procedure is said to be “manipulable by a coalition” if there is a group of individuals, and a preference profile, such that every member of the group prefers the choice set obtained when they are misrepresenting their preferences, to the one obtained when they are honest. We show that the Pareto rule, which is an aggregation procedure that maps profiles of individual preferences into corresponding sets of Pareto optima, is not manipulable by any coalition of individuals under various behavioural assumptions which relate preferences over choice sets to preferences over alternatives. The non-manipulability of the Pareto rule by a single individual follows as a special case under these behavioural assumptions.     

Preference for flexibility in the absence of learning: the risk attitude effect

Individuals’ preferences over opportunity sets may display “preference for flexibility” which prescribes to gradually eliminate alternatives from a given set until a final choice is made. One rationale for this preference for flexibility is individuals’ incentive to postpone the final choice in order to better learn their underlying preferences over basic alternatives. In this paper we show that even in the absence of learning, preference for flexibility arises if individuals are risk-averse or, at least, are not very risk-seeking. Thus, individual’s attitude towards risk provides yet another rationale for preference for flexibility. One of our results is that in the absence of learning, risk-neutral as well as risk-averse individuals display the same, maximal preference for flexibility. We thank Han Bleichrodt, Robert Dur, Chaim Fershtman, Maarten Janssen, Peran van Reeven, Peter Wakker, and Timothy van Zandt for helpful comments to and inspiring discussions. We are very grateful to the anonymous referee for very constructive comments and suggestions.     

A Solomonic solution to the problem of assigning a private indivisible good

A benevolent Planner wishes to assign an indivisible private good to n claimants, each valuing the object differently. Individuals have quasi-linear preferences. Therefore, the possibility of transfers is allowed. A second-best efficient mechanism is a strategy-proof and anonymous mechanism that is not Pareto dominated by another strategy-proof and anonymous mechanism. In this context, we identify three conditions that are necessary and, together with Voluntary Participation, sufficient for a mechanism to be second-best efficient. This set includes mechanisms that destroy the good at certain profiles. For domains comprising two individuals we provide an explicit characterization of the family of second-best efficient mechanisms.