The endowment effect and intertemporal choice: a laboratory investigation

We present a laboratory investigation of intertemporal choice (i.e., elicited discount rates) allowing for the influence of the endowment effect. Consistent with the previous literature, we hypothesize that the endowment effect in an intertemporal choice setting results in substantially higher discount rates relative to when individuals treat the resources in question as found money. Our results support this hypothesis and our experimental design provides a new protocol for conducting choice experiments wherein the endowment effect is an important determinant of behaviour.     

Rationalizable implementation

We consider the implementation of social choice functions under complete information in rationalizable strategies. A strict version of the monotonicity condition introduced by Maskin is necessary under the solution concept of rationalizability. Assuming the social choice function is responsive, i.e. in distinct states it selects distinct outcomes, we show that strict Maskin monotonicity is also sufficient under a mild “no worst alternative” condition. In particular, no economic condition is required. We discuss how our results extend when the social choice function is not responsive.     

ENDOGENOUS TIMING AND STRATEGIC CHOICE: THE COURNOT‐BERTRAND MODEL

Cournot establishes a Nash equilibrium to a duopoly game under output competition; Bertrand finds a different Nash equilibrium under price competition. Both treat the strategic choice variable (output versus price) and the timing of play as exogenous. We investigate Cournot‐Bertrand models where one firm competes in output and the other competes in price in both static and dynamic settings. We also develop a general model where both the timing of play and the strategic choice variables are endogenous. Consistent with the conduct of Honda and Scion, we show that Cournot‐Bertrand behaviour can be a Nash equilibrium outcome.     

INTERTEMPORAL UTILITY SMOOTHING: THEORY AND APPLICATIONS

This paper reviews models of intertemporal choice designed to be consistent with a phenomenon called a preference for spread; that is, where a decision‐maker prefers to spread good and bad consumption evenly over time. We closely examine the notion of utility smoothing adopted in these models as a source of the preference for spread. The paper also reviews extensions of these models where a strong aversion to volatility involved in a utility sequence causes preferences to be nonmonotone. Furthermore, to gain a better understanding of the behaviour implied by these models, we apply them to the Diamond growth model.     

Mechanism design with side payments: Individual rationality and iterative dominance

We investigate the collective decision with incomplete information and side payments. We show that a direct mechanism associated with the social choice function that satisfies budget balancing, incentive compatibility, and interim individual rationality exists for generic prior distributions. We consider the possibility that a risk-averse principal extracts full surplus in agency problems with adverse selection. With regard to generic prior distributions, we show that there exists a modified direct mechanism associated with the virtual social choice function, which satisfies budget balancing and interim individual rationality, such that truth telling is the unique three times iteratively undominated message rule profile.     

Pigouvian pricing and stochastic evolutionary implementation

We study the implementation of efficient behavior in settings with externalities. A planner would like to ensure that a group of agents make socially optimal choices, but he only has limited information about the agents’ preferences, and can only distinguish individual agents through the actions they choose. We describe the agents’ behavior using a stochastic evolutionary model, assuming that their choice probabilities are given by the logit choice rule. We prove that there is a simple price scheme with the following property: regardless of the realization of preferences, a group of agents subjected to the price scheme will spend the vast majority of time in the long run behaving efficiently. The price scheme defines a game that may possess multiple equilibria, but we are able to obtain a unique and efficient selection from this set because of the stochastic nature of the agents’ choice rule. We conclude by comparing the performance of our price scheme with that of VCG mechanisms.     

A characterization of consistent collective choice rules

We characterize a class of collective choice rules such that collective preference relations are consistent. Consistency is a weakening of transitivity and a strengthening of acyclicity requiring that there be no cycles with at least one strict preference, which excludes the possibility of a “money pump.” The properties of collective choice rules used in our characterization are unrestricted domain, strong Pareto, anonymity and neutrality. If there are at most as many individuals as there are alternatives, the axioms provide an alternative characterization of the Pareto rule. If there are more individuals than alternatives, however, further rules become available.     

Deliberative voting

We analyze a model of jury decision making in which jurors deliberate before casting their votes. We consider a wide range of voting institutions and show that deliberations render these equivalent with respect to the sequential equilibrium outcomes they generate. In particular, in the context of a jury setup, all voting rules excluding the two types of unanimity rules (one requiring a unanimous consensus to acquit, one requiring a unanimous consensus to convict) induce the same set of equilibria outcomes. We show the robustness of our results with respect to several restrictions on communication protocols and jurors’ strategies. Furthermore, we demonstrate that our observations extend to practically all of the voting structures commonly studied in the voting literature. The paper suggests the importance of accounting for communication in models of collective choice.     

ON DETAIL‐FREE MECHANISM DESIGN AND RATIONALITY*

Mechanism design theory has been criticized, because mechanisms depend on the detail of specification and agents’ behaviour relies on strong rationality assumptions. Hence the study of “detail‐free” mechanism design with weak rationality is important as a practical theory. This paper emphasizes that, even if we confine our attention to detail‐free mechanisms with weak rationality, there exists plenty of scope for the development of new and significant ideas. I describe my recent work along these lines, and argue that stochastic decisions work in large double auction environments, and that moral preferences improve the implementability of social choice functions.     

On the structure of choice under different external references

Summary. In this paper we fully characterize an individual's choice behaviour according to three different so–called external references. The first system which we describe axiomatically is standard utility maximization or preference optimization. The second approach characterizes the choice of the second largest element as an optimal choice, the third system is the choice of a medium element, also as a first best choice. For all three approaches, we have established a common axiomatic structure which allows us to point out rather precisely congruences and divergences among the different systems considered. Received: December 12, 1997; revised version: September 15, 1998     

The structure of strategy-proof social choice — Part I: General characterization and possibility results on median spaces

We define a general notion of single-peaked preferences based on abstract betweenness relations. Special cases are the classical example of single-peaked preferences on a line, the separable preferences on the hypercube, the “multi-dimensionally single-peaked” preferences on the product of lines, but also the unrestricted preference domain. Generalizing and unifying the existing literature, we show that a social choice function is strategy-proof on a sufficiently rich domain of generalized single-peaked preferences if and only if it takes the form of voting by issues (“voting by committees”) satisfying a simple condition called the “Intersection Property.”Based on the Intersection Property, we show that the class of preference domains associated with “median spaces” gives rise to the strongest possibility results; in particular, we show that the existence of strategy-proof social choice rules that are non-dictatorial and neutral requires an underlying median space. A space is a median space if, for every triple of elements, there is a fourth element that is between each pair of the triple; numerous examples are given (some well-known, some novel), and the structure of median spaces and the associated preference domains is analysed.     

Individual versus group strategy-proofness: When do they coincide?

A social choice function is group strategy-proof on a domain if no group of agents can manipulate its final outcome to their own benefit by declaring false preferences on that domain. There are a number of economically significant domains where interesting rules satisfying individual strategy-proofness can be defined, and for some of them, all these rules turn out to also satisfy the stronger requirement of group strategy-proofness. We provide conditions on domains guaranteeing that for all rules defined on them, individual and group strategy-proofness become equivalent. We also provide a partial answer regarding the necessity of our conditions.     

On the topological social choice model

The main goal of this paper is to show that if a finite connected CW complex admits a continuous, symmetric, and unanimous choice function for some number n>1 of agents, then the choice space is contractible. On the other hand, if one removes the finiteness, we give a complete characterization of the possible spaces; in particular, noncontractible spaces are indeed possible. These results extend earlier well-known results of Chichilnisky and Heal.     

Context effects: A representation of choices from categories

This paper studies a model of reference-dependent choice from sets of options grouped into categories. The proposed model is consistent with experimental evidence documenting context effects in a variety of choice situations. In our model, the reference point for any given category is subjective, and corresponds to the least preferred element in the category under consideration. Every object in a category is evaluated relative to the corresponding reference point; this may distort the objective ranking of options across different categories, and thus possibly give rise to a context-effects bias. The resulting representation is essentially unique. We also provide an economic application of the preferences that we axiomatize to principal-agent models. We show how sellers facing consumers exhibiting the context-effects bias can increase their profits by exploiting their bounded rationality.     

Beyond choice: investigating the sensitivity and validity of measures of strength of preference

Many experiments investigating different decision theories have relied heavily on pairwise choices between lotteries. These are easy to incentivise, but often yield only limited dichotomous information. This paper considers whether respondents’ judgments about their strength of preference (SoP) for one alternative over another can usefully supplement standard choice data. We report extensive evidence that such judgments show sensitivity to variations in question format and parameter values in the directions we should expect, not only within-subject but also between-sample. We illustrate how such judgments can usefully supplement standard pairwise choice data and enrich our understanding of observed behaviour.     

Temporal stability of preferences and willingness to pay for natural areas in choice experiments: A test–retest

The main objective of this paper is to test the temporal stability of stated preferences and willingness to pay (WTP) values from a Choice Experiment (CE) in a test–retest. The same group of participants was asked the same choice tasks in an internet-based CE, conducted twice with a time interval of one year without interviewer interference. We examine choice consistency at individual choice task level and transferability of the underlying indirect utility function and associated WTP values. The results show that choices are consistent in 57 percent of the choice occasions. Comparison of the choice models over time shows that the estimated preference and scale parameters are significantly different, suggesting that choice behaviour changed between the two surveys. Differences between marginal WTP estimates for individual choice attributes are statistically significant only at the 10 percent level. However, we show that this can result in significantly different WTP values for policy scenarios. The instability of estimated mean WTP values for different policy scenarios asks for caution when including WTP values in cost-benefit analysis.     

Modeling internal commitment mechanisms and self-control: A neuroeconomics approach to consumption–saving decisions

We provide a new model of consumption–saving decisions which explicitly allows for internal commitment mechanisms and self-control. Agents have the ability to invoke either automatic processes that are susceptible to the temptation of ‘over-consuming,’ or alternative control processes which require internal commitment but are immune to such temptations. Standard models in behavioral economics ignore such internal commitment mechanisms. We justify our model by showing that much of its construction is consistent with dynamic choice and cognitive control as they are understood in cognitive neuroscience.The dynamic consumption–saving behavior of an agent in the model is characterized by a simple consumption–saving goal and a cut-off rule for invoking control processes to inhibit automatic processes and implement the goal. We discuss empirical tests of our model with available individual consumption data and we suggest critical tests with brain-imaging and experimental data.     

FARSIGHTED COALITIONAL STABILITY OF A PRICE LEADERSHIP CARTEL

This paper analyzes the farsighted behaviour of firms that form a dominant price leadership cartel. We consider stability concepts such as the farsighted core, the farsighted stable sets, and the largest consistent set. We show that: (i) the farsighted core is either an empty set or a singleton set of the grand cartel; (ii) any Pareto efficient cartel is itself a farsighted stable set; and (iii) the set of cartels in which fringe firms enjoy higher profits than the firms in the minimal Pareto efficient cartel is the largest consistent set.     

Market experience eliminates some anomalies—and creates new ones

We report two experiments which investigate whether experience of decision making in repeated markets purges behaviour of preference reversals. We investigate two behavioural mechanisms that may be shaping bids in repeated auctions: A tendency to adjust bids towards previously observed market prices, and a tendency to reduce bids following bad market outcomes. We find little support for the former but strong support for the latter. Also, whilst ‘just enough’ market exposure eliminates the typical preference reversal phenomenon, continued exposure fosters the mirror image anomaly. Therefore, although market experience shapes behaviour, in our experiments, it does not generally promote consistency with standard preference theory.     

Cumulative prospect theory and the St. Petersburg paradox

Summary. We find that in cumulative prospect theory (CPT) with a concave value function in gains, a lottery with finite expected value may have infinite subjective value. This problem does not occur in expected utility theory. The paradox occurs in particular in the setting and the parameter regime studied by Tversky and Kahneman [15] and in subsequent works. We characterize situations in CPT where the problem can be resolved. In particular, we define a class of admissible probability distributions and admissible parameter regimes for the weighting- and value functions for which finiteness of the subjective value can be proved. Alternatively, we suggest a new weighting function for CPT which guarantees finite subjective value for all lotteries with finite expected value, independent of the choice of the value function. Some of these results have already been found independently by Blavatskyy [4] in the context of discrete lotteries.Received: 14 October 2004, Revised: 6 May 2005, JEL Classification Numbers: C91, D81.We thank Pavlo Blavatskyy and Thorsten Hens for their helpful remarks regarding our paper. Moreover, we thank the referee for his constructive suggestions. This research was supported by the University Research Priority Program “Finance and Financial Markets” a research instrument of the University of Zürich.