Remarks on the consumer problem under incomplete preferences

This article revisits the standard results of demand theory when the preference relation is a continuous preorder that admits an equicontinuous multi-utility representation. We study the consumer problem as the constrained maximization of a continuous vector-valued utility mapping, and show how to rederive those results. In particular, we provide a link between the literature on vector optimization and the analysis of the consumer problem under incomplete preferences.     

Time preferences and risk aversion: Tests on domain differences

Understanding how individuals discount and evaluate the risks of environmental outcomes is a prime component in designing effective environmental policy. We use an incentivized experimental design to investigate whether subjects’ time preferences and risk aversion across the monetary and environmental domains differ. We find that subjects’ time preferences are not significantly different across the two domains. In contrast, subjects exhibit a higher degree of risk aversion in the environmental domain. Furthermore, we corroborate earlier results, documenting that women are more risk averse than men in the monetary domain, and show this finding to also hold in the environmental domain.     

Individual vs. couple behavior: an experimental investigation of risk preferences

In this article, we elicit both individuals’ and couples’ preferences assuming prospect theory (PT) as a general theoretical framework for decision under risk. Our experimental method, based on certainty equivalents, allows to infer measurements of utility and probability weighting at the individual level and at the couple level. Our main results are twofold. First, risk attitude for couples is compatible with PT and incorporates deviations from expected utility similar to those found in individual decision making. Second, couples’ attitudes towards risk are found to be consistent with a mix of individual attitudes, women being more influent on couples’ preferences at low probability levels.     

Democracy and interdependent preferences

In a democracy, the views and wishes of the citizens are to count. The problem here is how this dictum is to be understood. I suggest that a proper analysis requires that each person's preferences be seen in the context of his beliefs concerning the preferences of the others and of the preferences he would have if he held different beliefs. Preferences founded on erroneous beliefs call for special consideration. So also do certain reluctantly held preferences. I propose a decision-policy involving the identification of social equilibria of preference.     

Uncertain discount and hyperbolic preferences

This paper studies the interaction between savagean uncertainty and time preferences. We introduce a variation of the discounted subjective expected utility model, where time preferences are state dependent. Before uncertainty is resolved, the individual is unsure about the discount factor that will be used, even when evaluating certain payoffs. The model can account for the present bias and diminishing impatience, even if the future is discounted geometrically. The present bias disappears when the immediate payoff becomes uncertain. Although preferences are not stationary, choices may be time consistent.     

Heterogeneous risk and time preferences

Assessing individuals’ time and risk preferences is crucial in domains such as health-related decisions (e.g., dieting, addictions), environmentally-friendly practices, and saving opportunities. We propose a new method to jointly elicit and estimate risk attitudes and intertemporal choices. We use a novel individual level estimation procedure based on a hierarchical Bayes methodology, which can integrate different functional forms for discounting and risk attitudes. This method provides individual level estimates, and allows us to explore the heterogeneity in the data. In addition, we report a negative correlation between risk and time preferences, implying that risk-seeking individuals are less patient and less willing to defer consumption.     

Dopamine receptor genes predict risk preferences,time preferences,and related economic choices

Outside of economics, researchers have recently identified genetic predictors of “sensation-seeking” that have been linked to risky and impulsive behaviors. We examine the implications of these genetic polymorphisms for economic behavior. Our analysis indicates that the 7-repeat allele of the DRD4 gene that regulates dopamine uptake in the brain predicts risk-taking and time preferences in economic experiments that allow for ambiguity, losses and discounting. These genetic polymorphisms can also be used to directly predict financial choice patterns that are consistent with previous findings in the behavioral genetics literature.     

Imprecise preferences and the WTP-WTA disparity

This article reports the results of a study designed to elicit willingness to pay (WTP) and willingness to accept (WTA) values for changes in the risk of nonfatal road injuries. We examine the possibility that individuals' preferences over combinations of wealth, risk, and safety are imprecise, and that this imprecision might result in the observed disparity between WTP and WTA measures of value. The results confirm that individuals' preferences for safety are significantly imprecise, but that this alone is insufficient to explain more than part of the disparity. Indeed, respondents' estimates of the minimum that they would be prepared to accept for a risk increase frequently exceed the maximum that they would be prepared to pay for an equivalent risk reduction.     

Noise and bias in eliciting preferences

In the context of eliciting preferences for decision making under risk, we analyse the features of four different elicitation methods—pairwise choice, willingness-to-pay, willingness-to-accept, and the Becker-DeGroot-Marschak mechanism—and estimate noise, bias and risk attitudes for two different preference functionals, Expected Utility and Rank-Dependent Expected Utility. It is well-known that methods differ in terms of the bias in the elicitation; it is rather less well-known that methods differ in terms of their noisiness. It has also been reported that risk attitudes are not stable across different elicitation methods. Our results suggest that elicited preferences should only be used in the context in which they were elicited, and the bias in the certainty-equivalent methods should be kept in mind when making predictions based on the elicited preferences. Moreover, conclusions should be moderated to take into account the various methods’ noise, which is generally lowest in the case of pairwise choice.     

Interpersonal dependency of preferences

Standard decision theoretic models disregard the phenomenon of interpersonal dependency of preferences. In this paper it is argued that interpersonal dependency of preferences is a serious challenge for standard utility theory. First we sketch the more philosophical aspects of the problem and then, using a simple, formal model for the two-person case, we show that interpersonal dependency of preferences generally results in indeterminacy of preferences (resp. of subjective utility).     

Subjective probabilities and utility with event-dependent preferences

This article generalizes Savage's theory to include event-dependent preferences. The state space is partitioned into finitely many events. The induced preferences over consequences are assumed independent of the underlying states within, but not across, these events. This results in an additively separable representation of preferences over acts. The dependence of the preference relation over consequences on the events is represented by event-dependent mappings of the set of consequences onto itself. Given these mappings, the preferences on acts are represented by the expectation of event-dependent utilities on the consequences with respect to unique subjective probabilities on the states.Helpful discussions with David Schmeidler are gratefully acknowledged.     

Risk preferences and changes in background risk

We present two theorems that yield necessary and sufficient conditions for first- and second-degree stochastic dominance deteriorations of background risk to increase risk aversion with respect to foreground risk. We require that any change in a foreground risk that is undesirable remains so after a background risk changes in a way that is either unfair, undesirable in the sense of reducing expected utility, or undesirable in the sense of increasing expected marginal utility. Our results thus characterize utility functions that are, respectively, vulnerable, proper, or standard with respect to changes in background risk.

Mean variance preferences and the heat equation

Chipman (1979) proves that for an expected utility maximizer choosing from a domain of normal distributions with mean and variance ² the induced preference functionV(, ) satisfies a differential equation known as the heat equation. The purpose of this note is to provide a generalization and simple proof of this result which does not depend on the normality assumption.     

Nontransitive preferences in decision theory

Intransitive preferences have been a topic of curiosity, study, and debate over the past 40 years. Many economists and decision theorists insist on transitivity as the cornerstone of rational choice, and even in behavioral decision theory intransitivities are often attributed to faulty experiments, random or sloppy choices, poor judgment, or unexamined biases. But others see intransitive preferences as potential truths of reasoned comparisons and propose representations of preferences that accommodate intransitivities. This article offers a partial survey of models for intransitive preferences in a variety of decisional contexts. These include economic consumer theory, multiattribute utility theory, game theory, preference between time streams, and decision making under risk and uncertainty. The survey is preceded by a discussion of issues that bear on the relevance and reasonableness of intransitivity.     

Elicitation of preferences under ambiguity

This paper is about behaviour under ambiguity—that is, a situation in which probabilities either do not exist or are not known. Our objective is to find the most empirically valid of the increasingly large number of theories attempting to explain such behaviour. We use experimentally-generated data to compare and contrast the theories. The incentivised experimental task we employed was that of allocation: in a series of problems we gave the subjects an amount of money and asked them to allocate the money over three accounts, the payoffs to them being contingent on a ‘state of the world’ with the occurrence of the states being ambiguous. We reproduced ambiguity in the laboratory using a Bingo Blower. We fitted the most popular and apparently empirically valid preference functionals [Subjective Expected Utility (SEU), MaxMin Expected Utility (MEU) and α-MEU], as well as Mean-Variance (MV) and a heuristic rule, Safety First (SF). We found that SEU fits better than MV and SF and only slightly worse than MEU and α-MEU.     

Taste uncertainty and status quo effects in consumer choice

We use reference-dependent expected utility theory to develop a model of status quo effects in consumer choice. We hypothesise that, when making their decisions, individuals are uncertain about the utility that will be yielded by their consumption experiences in different ‘taste states’ of the world. If individuals have asymmetric attitudes to gains and losses of utility, the model entails acyclic reference-dependent preferences over consumption bundles. The model explains why status quo effects may vary substantially from one decision context to another and why some such effects may decay as individuals gain market experience.