The relationship between individual expectations and behaviors: Mortality expectations and smoking decisions

Using data from the Health and Retirement Study, we assess the accuracy of subjective beliefs about mortality and objectively estimated probabilities for individuals in the same sample. Overall, subjective beliefs and objective probabilities are very close. However, there are differences conditional on behaviors, with current smokers being relatively optimistic and never smokers relatively pessimistic in their assessments. In the aggregate, individuals accurately predict longevity, but at the individual level, subjective beliefs provide information in addition to the estimated objective probabilities in predicting actual events, which may arise from the effect of past or anticipated decisions on these beliefs.

Third-generation prospect theory

We present a new theory of decision under uncertainty: third-generation prospect theory (PT³). This retains the predictive power of previous versions of prospect theory, but extends that theory by allowing reference points to be uncertain while decision weights are specified in a rank-dependent way. We show that PT³ preferences respect a state-conditional form of stochastic dominance. The theory predicts the observed tendency for willingness-to-accept valuations of lotteries to be greater than willingness-to-pay valuations. When PT³ is made operational by using simple functional forms with parameter values derived from existing experimental evidence, it predicts observed patterns of the preference reversal phenomenon.

Pre-commitment and flexibility in a time decision experiment

An agent with dynamically inconsistent preferences may deviate from her plan of action as the future draws near. An exponential discounter may do exactly the same when facing an uncertain future. Through an experiment we compare preference-based vs. uncertainty-based explanations for choice reversal over time by eliciting choices for pre-commitment and flexibility. Evidence of widespread commitment favors a preference-based explanation.

Counting casualties: A framework for respectful,useful records

Counting casualties in conflict zones faces both practical and ethical concerns. Drawing on procedures from risk analysis, we propose a general approach. It represents each death by standard features, having either essential value, for capturing the social and cultural meaning of individual casualties, or instrumental value, for relating patterns of casualties to possible causes and effects. We illustrate the approach with the choices involved in attempts to record casualties in Iraq and the Israel-Palestine conflict, and with natural disasters, as exemplified by Hurricane Katrina. We advocate institutionalizing the approach, so that recording casualties increases understanding, rather than suspicion.

Self-protection and insurance with interdependencies

We study optimal investment in self-protection of insured individuals when they face interdependencies in the form of potential contamination from others. If individuals cannot coordinate their actions, then the positive externality of investing in self-protection implies that, in equilibrium, individuals underinvest in self-protection. Limiting insurance coverage through deductibles or selling “at-fault” insurance can partially internalize this externality and thereby improve individual and social welfare.

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.

Conditional payments and self-protection

Self-protection can be financed either by upfront payments or by conditional payments (or contingent fees) in which individuals pay a provider only when a favorable outcome is realized. We find that, from the vantage point of a risk-averse individual, conditional payments welfare dominate upfront payments in the state-independent framework, but upfront payments welfare dominate conditional payments in the state-dependent framework. Moreover, more risk aversion always implies more self-protection under conditional payments, for both state-independent and state-dependent frameworks. In contrast, it has been previously argued that more risk aversion does not necessarily imply more self-protection under upfront payments.

Individual and group decision making under risk: An experimental study of Bayesian updating and violations of first-order stochastic dominance

This paper reports the results of experiments designed to test whether individuals and groups abide by monotonicity with respect to first-order stochastic dominance and Bayesian updating when making decisions under risk. The results indicate a significant number of violations of both principles. The violation rate when groups make decisions is substantially lower, and decreasing with group size, suggesting that social interaction improves the decision-making process. Greater transparency of the decision task reduces the violation rate, suggesting that these violations are due to judgment errors rather than the preference structure. In one treatment, however, less complex decisions result in a higher error rates.

Gender,risk and stereotypes

This paper reports results from an economic experiment where respondents are asked to make choices between risky outcomes for themselves and others. We investigate whether subjects’ own risk preferences and gender stereotypes are reflected in the predictions they make for the risk preferences of others and the way this occurs. When predicting other people’s risk preferences, the respondents tend to use a combination of their own risk preferences and stereotypes. Moreover, when making risky choices for others, the respondents generally use a combination of their own risk preferences and their average predicted risk preference of the targeted group.

The ostrich effect: Selective attention to information

We develop and test a model which links information acquisition decisions to the hedonic utility of information. Acquiring and attending to information increases the psychological impact of information (an impact effect), increases the speed of adjustment for a utility reference-point (a reference-point updating effect), and affects the degree of risk aversion towards randomness in news (a risk aversion effect). Given plausible parameter values, the model predicts asymmetric preferences for the timing of resolution of uncertainty: Individuals should monitor and attend to information more actively given preliminary good news but “put their heads in the sand” by avoiding additional information given adverse prior news. We test for such an “ostrich effect” in a finance context, examining the account monitoring behavior of Scandinavian and American investors in two datasets. In both datasets, investors monitor their portfolios more frequently in rising markets than when markets are flat or falling.

Predicted risk perception and risk-taking behavior: The case of impaired driving

Research suggests an association between risk perception and risk-taking behavior in a variety of contexts. There is empirical evidence that perceived risk is generally biased and that perception of risk influences behavior. Perception of risk can be endogenous. It is therefore more appropriate to instrument risk perception. This article studies the perception of the risks associated with impaired driving and the relation between predicted risk perception and driving behavior. We survey a sample of license-holders, half of whom are drivers with a past conviction for impaired driving, the other half or control group without such conviction. Predicted perceptual biases are shown to influence actual driving behavior.

Risk aversion and expected-utility theory: A calibration exercise

Rabin (Econometrica 68(5):1281–1292, 2000) argues that, under expected-utility, observed risk aversion over modest stakes implies extremely high risk aversion over large stakes. Cox and Sadiraj (Games Econom. Behav. 56(1):45–60, 2006) have replied that this is a problem of expected-utility of wealth, but that expected-utility of income does not share that problem. We combine experimental data on moderate-scale risky choices with survey data on income to estimate coefficients of relative risk aversion using expected-utility of consumption. Assuming individuals cannot save implies an average coefficient of relative risk aversion of 1.92. Assuming they can decide between consuming today and saving for the future, a realistic assumption, implies quadruple-digit coefficients. This gives empirical evidence for narrow bracketing.

A tractable method to measure utility and loss aversion under prospect theory

This paper provides an efficient method to measure utility under prospect theory. Our method minimizes both the number of elicitations required to measure utility and the cognitive burden for subjects, being based on the elicitation of certainty equivalents for two-outcome prospects. We applied our method in an experiment and were able to replicate the main findings on prospect theory, suggesting that our method measures what it is intended to. Our data confirmed empirically that risk seeking and concave utility can coincide under prospect theory. Utility did not depend on the probability used in the elicitation, which offers support for the validity of prospect theory.

A Bayesian examination of information and uncertainty in contingent valuation

A theoretical framework is presented to explain how agents respond to information under uncertainty in contingent valuation surveys. Agents are provided with information signals and referendum prices as part of the elicitation process. Agents use Bayesian updating to revise prior distributions. An information prompt is presented to reduce hypothetical bias. However, we show the interaction between anchoring and the information prompt creates a systematic bias in willingness to pay. We test our hypotheses in an experimental setting where agents are asked to make a hypothetical, voluntary contribution to a public good. Experimental results are consistent with the model.

Whom should we believe? Aggregation of heterogeneous beliefs

We examine the collective risk attitude of a group with heterogeneous beliefs. We prove that the wealth-dependent probability distribution used by the representative agent is biased in favor of the beliefs of the more risk tolerant consumers. Moreover, increasing disagreement on the state probability raises the state probability of the representative agent. It implies that when most disagreements are concentrated in the tails of the distribution, the perceived collective risk is magnified. This can help to solve the equity premium puzzle. We show that the trade volume and the equity premium are positively correlated.

Valuing publicly sponsored research projects: Risks,scenario adjustments,and inattention

Survey-based choice scenarios used to value non-market public goods typically preclude any risk that the benefits described may not be delivered. Our survey specifies explicit risks of (a) outright program failure and (b) program redundancy due to possible private sector substitutes. Additionally, most analyses assume that survey subjects fully accept these scenarios and that all provided information receives their complete attention. Our discounted expected utility model of choice accommodates both these objective risks and the possibility of subjective scenario adjustment or selective inattention by respondents. We then counterfactually simulate willingness-to-pay in the absence of these distortions.