OBEN K. BAYRAK

When people take decisions under risk, it is not only the expected utility that is important, but also the shape of the distribution of utility: clearly the dispersion is important, but also the skewness. For given mean and dispersion, decision-makers treat positively and negatively skewed prospects differently. This paper presents a new behaviourally-inspired model for decision making under risk, incorporating both dispersion and skewness. We run a horse-race of this new model against six other models of decision-making under risk and show that it outperforms many in terms of goodness of fit and shows a reasonable performance in predictive ability. It can incorporate the prominent anomalies of standard theory such as the Allais paradox, the valuation gap, and preference reversals, and also the behavioural patterns observed in experiments that cannot be explained by Rank Dependent Utility Theory.

​​The term ‘preference imprecision’ seems to have different meanings to different people. In the literature, one can find references to a number of expressions. For example: vagueness, incompleteness, randomness, unsureness, indecisiveness and thick indifference curves. Some of these are theoretical constructs, some are empirical. The purpose of this paper is to survey the various different approaches and to try to link them together: to see if they are all addressed to the same issue, and to come to some conclusions. In the course of this survey, we report on evidence concerning the existence of preference imprecision, and its impact on theoretical and empirical work.

This article presents a new model for decision-making under risk, which provides an explanation for empirically-observed preference reversals. Central to the theory is the incorporation of probability perception imprecision, which arises because of individuals’ vague understanding of numerical probabilities. We combine this concept with the use of the Alpha EU model and construct a simple model which helps us to understand anomalies, such as preference reversals and valuation gaps, discovered in the experimental economics literature, that standard models cannot explain.

We extend the literature on the willingness-to-pay/willingness-to-accept (WTP/WTA) disparity by testing two hypotheses, distilled from the literature. We also introduce a modified mechanism for eliciting the subjective valuation range if the individual cannot articulate the subjective value as a precise amount confidently. We elicited valuations for four goods: three ordinary market goods and a lottery ticket. Under the conventional setting in which subjects are asked to state a single precise amount, we observed a significant disparity for the lottery ticket. On the other hand, our key finding is that the disparity disappears under the intervals treatment, suggesting that response format is important, given that earlier experimental studies invariably uses point values (i.e. open ended questions about WTP/WTA). Moreover, for the risky prospect we observe that from their admissible range the buyers state the lower bound as their WTP whereas sellers state the upper bound as their WTA. We conclude that this type of behavior can to some extent explain the observed disparity at least for the risky prospects.