Evolutionary stability and lexicographic preferences

We explore the interaction between evolutionary stability and lexicographic preferences. To do so, we define a limit Nash equilibrium for a lexicographic game as the limit of Nash equilibria of nearby games with continuous preferences. Nash equilibria of lexicographic games are limit Nash equilibria, but not conversely. Modified evolutionarily stable strategies (Binmore and Samuelson, 1992. J. Econ. Theory 57, 278–305) are limit Nash equilibria. Modified evolutionary stability differs from “lexicographic evolutionarily stability” (defined by extending the common characterization of evolutionary stability to lexicographic preferences) in the order in which limits in the payoff space and the space of invasion barriers are taken.     

Utility from anticipation and personal equilibrium

I develop a dynamic model of individual decisionmaking in which the agent derives utility from physical outcomes as well as from rational beliefs about physical outcomes (“anticipation”), and these two payoff components can interact. Beliefs and behavior are jointly determined in a personal equilibrium by the requirement that behavior given past beliefs must be consistent with those beliefs. I explore three phenomena made possible by utility from anticipation, and prove that if the decisionmaker’s behavior is distinguishable from a person’s who cares only about physical outcomes, she must exhibit at least one of these phenomena. First, the decisionmaker can be prone to self-fulfilling expectations. Second, she might be time-inconsistent even if her preferences in all periods are identical. Third, she might exhibit informational preferences, where these preferences are intimately connected to her attitudes toward disappointments. Applications of the framework to reference-dependent preferences, impulsive behaviors, and emotionally difficult choices are discussed.     

Evolution of Walrasian equilibrium in an exchange economy

We study the stochastic stability of a dynamic trading process in an exchange economy. We use a simplified version of a trading model à la Shapley and Shubik (J Polit Econ 85:937–968, 1977). Two types of agents equipped with Leontief preferences trade goods in markets by offering endowments, and actual trades occur at market clearing prices. Better behavior tends to spread through the same type of agents by imitation, and agents also make mistakes occasionally. We provide a sufficient condition for the perturbed dynamic process to have a unique stochastically stable state that is a Walrasian equilibrium allocation. In this sense, we give a rationale for Walrasian behavior.     

Optimal growth with many consumers

A method is described for constructing all Pareto-optimal allocations for a dynamic economy with many heterogeneous consumers, under certainty, in which both the technology and consumer preferences are recursive but preferences need not be additively separable over time. Optimal (perfect foresight competitive equilibrium) allocations are obtained through the study of a dynamic program. For an economy with one consumption good, sufficient conditions are given for the existence of a unique interior stationary distribution of consumption and wealth. For a two-person exchange economy, sufficient conditions are given for the global asymptotic stability of the unique interior stationary point.     

The Dynamic Evolution of Preferences

This paper develops a general methodology for characterizing the dynamic evolution of preferences in a wide class of strategic interactions. We give simple conditions characterizing the limiting distribution of preferences in general games, and apply our results to study the evolutionary emergence of overconfidence and interdependent preferences. We also show that this methodology can be adapted to cases where preferences are only imperfectly observed. Earlier drafts of this paper were circulated under the title: “The Evolution of Perception Biases” and some of these results appeared in the earlier working paper Heifetz, Shannon and Spiegel (2003). We thank three anonymous referees for their helpful comments. Shannon thanks the NSF for research support under grant SES-0351346.     

Credible group stability in many-to-many matching problems

It is known that in two-sided many-to-many matching problems, pairwise-stable matchings may not be immune to group deviations, unlike in many-to-one matching problems (Blair, 1988). In this paper, we show that pairwise stability is equivalent to credible group stability when one side has responsive preferences and the other side has categorywise-responsive preferences. A credibly group-stable matching is immune to any “executable” group deviations with an appropriate definition of executability. Under the same preference restriction, we also show the equivalence between the set of pairwise-stable matchings and the set of matchings generated by coalition-proof Nash equilibria of an appropriately defined strategic-form game.     

Unambiguous events and dynamic Choquet preferences

This paper explores the relationship between dynamic consistency and existing notions of unambiguous events for Choquet expected utility preferences. A decision maker is faced with an information structure represented by a filtration. We show that the decision maker’s preferences respect dynamic consistency on a fixed filtration if and only if the last stage of the filtration is composed of unambiguous events in the sense of Nehring (Math Social Sci 38:197–213, 1999). Adopting two axioms, conditional certainty equivalence consistency and constrained dynamic consistency to filtration measurable acts, it is shown that the decision maker respects these two axioms on a fixed filtration if and only if the last stage of the filtration is made up of unambiguous events in the sense of Zhang (Econ Theory 20:159–181, 2002).     

Interdependent Preferences and Groups of Agents

An individual's preferences are assumed to be malleable and may be influenced by the preferences of others. Mutual interaction among individuals whose preferences are interdependent powers a dynamic process in which preference profiles evolve over time. Two formulations of the dynamic process are presented. One is an abstract model in which the iteration of a mapping from profiles to profiles defines a discrete time dynamic process; the other is a linear discrete time process specified in more detail. Examples motivate the model and illustrate its application. Conditions are given for the existence of a stable preference profile—a rest point of the dynamic process. A stable profile is naturally associated with a division, not in general unique, of the set of agents into subgroups with the property that preference interdependencies within a subgroup are "stronger" than those across subgroups. The conventional case in which each agent's preference relation is exogenously given is, in this model, the special case where each subgroup consists of just one agent.     

The microfoundation of macroeconomic populism: The effects of economic inequality on public inflation aversion

Previous work on the politics of monetary policy has focused on the role of distributive motives stemming from individual characteristics such as income or factoral/sectoral interests in citizens' formation of monetary policy preferences. However, the existing literature has paid little attention to how a country's overall distributive context, namely, its level of economic inequality, affects citizens' preferences vis-à-vis price stability and employment. This article argues that as inequality pushes more citizens below a society's average income, there is more demand for redistribution through higher employment and increased fiscal spending, each of which can be better supported by expansionary monetary policy. This means that inequality makes citizens more tolerant of inflation. This study uses the International Social Survey Program, the Integrated Values Surveys, and the Comparative Study of Electoral Systems, which together include 293,100 respondents from 53 countries between the years 1976 and 2016 to demonstrate that overall, inequality significantly moderates citizens' inflation aversion.     

Stochastically independent randomization and uncertainty aversion

Summary.   This paper proposes a preference-based condition for stochastic independence of a randomizing device in a product state space. This condition is applied to investigate some classes of preferences that allow for both independent randomization and uncertainty or ambiguity aversion (a la Ellsberg). For example, when imposed on Choquet Expected Utility (CEU) preferences in a Savage framework displaying uncertainty aversion in the spirit of Schmeidler [27], it results in a collapse to Expected Utility (EU). This shows that CEU preferences that are uncertainty averse in the sense of Schmeidler should not be used in settings where independent randomization is to be allowed. In contrast, Maxmin EU with multiple priors preferences continue to allow for a very wide variety of uncertainty averse preferences when stochastic independence is imposed. Additionally, these points are used to reexamine some recent arguments against preference for randomization with uncertainty averse preferences. In particular, these arguments are shown to rely on preferences that do not treat randomization as a stochastically independent event. Received: February 10, 2000; revised version: March 30, 2000     

Stable matchings and preferences of couples

Couples looking for jobs in the same labor market may cause instabilities. We determine a natural preference domain, the domain of weakly responsive preferences, that guarantees stability. Under a restricted unemployment aversion condition we show that this domain is maximal for the existence of stable matchings. We illustrate how small deviations from (weak) responsiveness, that model the wish of couples to be closer together, cause instability, even when we use a weaker stability notion that excludes myopic blocking. Our remaining results deal with various properties of the set of stable matchings for “responsive couples markets”, viz., optimality, filled positions, and manipulation.     

Quasi-hyperbolic preferences and retirement: A comment

Diamond and Koszegi [Diamond, P. and Koszegi, B. (2003), “Quasi-Hyperbolic Preferences and Retirement,” Journal of Public Economics, 87: 1839–1972] have argued that quasi-hyperbolic discounting can cause dynamic inconsistency in planning when to retire as well as in consumption plans. This comment shows that in a simple model with such preferences, retirement plans are never time-inconsistent, as these same preferences keep savings too low for individuals to ever be able to afford unplanned early retirement. Although only a simple example is presented here to demonstrate the point, this insight suggests the application of ordiamond03's framework should be reconsidered. The model presented needs to be extended to find robust general conclusions.     

Optimal stopping with dynamic variational preferences

We solve optimal stopping problems in uncertain environments for agents assessing utility by virtue of dynamic variational preferences as in Maccheroni, Marinacci and Rustichini (2006) [16] or, equivalently, assessing risk in terms of dynamic convex risk measures as in Cheridito, Delbaen and Kupper (2006) [4]. The solution is achieved by generalizing the approach in Riedel (2009) [21] introducing the concept of variational supermartingales and variational Snell envelopes with an accompanying theory. To illustrate results, we consider prominent examples: dynamic multiplier preferences and a dynamic version of generalized average value at risk introduced in Cheridito and Tianhui (2009) [5].     

Dynamic consistency for non-expected utility preferences

This paper considers a generalization of the Savage framework in which there are two state spaces as follows: one to model events and one to define acts. The distinction between these two spaces typically induces non-consequentialist motives. The dynamic derivation of the Sure Thing Principle is studied in this framework. When these two spaces are substantially different, there exists a class of preferences that satisfy dynamic consistency and, at the same time, rationalize violations of the Sure Thing Principle. Consequently, it is possible to use non-expected utility preferences to study problems with dynamic consistency, as long as preferences belong to the previous class and as long as problems refer to information structures, defined as partitions over the set that serves to model events.     

Equilibrium selection and the dynamic evolution of preferences

A population of fully rational agents plays a symmetric 2-player game in biological fitnesses, but each agent?s play is determined by his payoffs, which are free to evolve according to “survival of the fittest” pressures. An equilibrium-selection mechanism is assumed to exist, and deliver a unique outcome for any given profile of payoffs; this allows the evolution of payoffs to be modeled as a well-defined replicator dynamics. The existing static stability results that “efficient strict Nash implies stability” and “stability implies efficiency” are translated to this dynamic context, although the latter gives way to indeterminacy in the absence of a specific equilibrium-selection mechanism. A strong form of stability is established for the efficient outcome of games with common interests, whilst a weaker stability result is provided for efficient mixed-strategy equilibria of doubly symmetric games. The results are illustrated using the equilibrium-selection mechanism provided by global games.     

Are bid preferences benign? The effect of small business subsidies in highway procurement auctions

Bid preferences in procurement auctions allow firms from an identifiable group an advantage in bidding against unfavored firms. While economic efficiency is expected to fall as a result of bid preferences, government procurement costs may either increase or decrease depending on the competitive response of favored and unfavored firms. This paper uses data from California auctions for road construction contracts, where small businesses receive a 5-percent bid preference in auctions for projects using only state funds and no preferential treatment on projects using federal aid. I show that while firms' bidding behavior matches theoretical predictions, procurement costs are 3.8 percent higher on auctions using preferences. The higher procurement cost in preference auctions is attributed to reduced participation by lower cost large firms.Structural estimates of latent firm costs are then used to evaluate how efficiency and the division of surplus between firms and the government are impacted by bid preferences. Firm profits are 3.1 percent lower under bid preferences, however this is overwhelmed by the efficiency loss due to reduced large firm participation. The efficiency loss conditional on firm participation is estimated to represent around 0.1 percent of overall procurement costs. Including the adverse effect of preferences on the participation of large firms increases the estimated efficiency loss to 3.6 percent, which represents 27 cents for each additional dollar awarded to small businesses through the program. Counterfactual simulations indicate that if participation were instead inelastic to bid preferences, the 5-percent bid preference would be close to the optimal level.     

Equilibrium in a reinsurance market with short sale constraints

Summary. This paper deals with the existence of equilibrium in a dynamic reinsurance market with short sale constraints, driven by a marked point process, as studied in Bernis and Jouini (2001). We use the set of reinsurance treaties as consumption set, which is the positive orthant of some Banach lattice that can be identified to a space of martingales, . The properness of preferences is a key assumption for us to prove the existence of an equilibrium. We provide a sufficient condition for the preferences to be proper in term of loading factor of the reinsurance premium. Received: June 15, 2000; revised version: May 17, 2001     

International trade and “Catching up with the Joneses”: Are the consumption patterns convergent?

We use a dynamic international trade model to analyse the implications of international trade for agents’ preferences and economic growth. This model is based on the home market effect with external habit formation (“catching up with the Joneses”) and “learning by doing” in production. We demonstrate the following: the historical composition of consumption in countries determines industrialization after trade; the preferences of agents converge after trade, independent of the economic results; and the welfare effects of trade may be positive or negative depending on trading partner characteristics. In some scenarios, autarky is strictly preferred to trade. Thus, international trade does not necessarily imply greater welfare, as is the typical result in a static context under CES preferences.     

Macroeconomic Linkages and Regional Monetary Cooperation: Steps Ahead*

There is a growing appetite for economic cooperation in East Asia. Although the region has forums to facilitate this, economic cooperation has focussed largely on discussion of issues and policies ? cooperative action is confined to functional cooperation in finance. There is scope for further cooperation in strengthening markets and institutions, with a view to accelerating convergence and stability in the region and deepening shared preferences about policy objectives, including on monetary and exchange rate issues. Although monetary policy in East Asia is generally focussed on controlling inflation, differences remain in economic structure and preferences about policy trade‐offs, markets, and institutions.     

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.