Reaction to Uncertainty and Market Mechanism:Experimental Evidence

Abstract Much of the evidence supporting the Ellsberg's paradox comes from experiments on individual choice and judgement. In this study, we address the issue whether, in market experiments, there is a tendency for anomalous behaviour to disappear or to be reduced as a consequence of market experience and feedback. We empirically test the validity of this assumption by running an auction market for the sale of both risky and uncertain prospects. We compare bidding behaviour and prices in market-like settings with valuations obtained from individual pricing tasks. We conclude that, with the repetition of the market experience, there is a tendency for subjective expected utility to perform better. However, economists' general assumption that, in laboratory experiments, poor performance of SEU is due to the lack of financial incentives or to the lack of market-like settings is by no means supported by our data.

The effect of elicitation methods on ambiguity aversion: an experimental investigation

In this paper we elicit preferences for the classical three-color Ellsberg Paradax employing three different methods, choices, minimal selling prices and maximal buying prices. The resulting data reveal a high frequency of preference reversals which have not been analyzed before in choice under uncertainty. Moreover, we analyze the effect of elicitation methods on the degree of ambiguity aversion. While there is no apparent difference in the attitude towards ambiguity between selling and buying prices we observe a rather distinct pattern of behavior for choices: Compared to choices, eliciting preferences by pricing tasks decreases the number of subjects being ambiguity averse in both tasks and increases the number of subjects being ambiguity neutral or prone. We argue that this difference between pricing and choice supports the hypothesis of comparative ignorance.Ellsberg Paradox, ambiguity aversion, preference reversal, comparative ignorance

Choquet OK?

There is a large theoretical literature in both economics and psychology on decision making under ambiguity (as distinct from risk) and many preference functionals proposed in this literature for describing behaviour in such contexts. However, the empirical literature is scarce and largely confined to testing between various proposed functionals. Using a new design, in which we create genuine ambiguity in the laboratory and can control the amount of ambiguity, we generate data which enables us to estimate several of the proposed preference functionals. In particular, we fit Subjective Expected Utility, Prospect Theory, Choquet Expected Utility, Maximin, Maximax, and Minimum Regret preference functionals, and examine how the fit changes when we vary the ambiguity. We find that the Choquet formulation performs best overall, though it is clear that different decision makers have different functionals. We also identify new decision rules which are not explicitly modelled in the literature.Ambiguity, Subjective Expected Utility, Prospect Theory, Choquet Expected Utility, Decision Making, Maximin, Maximax, Minimum Regret, Bingo Blower

Reaction to uncertainty and market mechanism : experimental evidence

Much of the evidence supporting the Ellsberg's paradox comes from experiments on individual choice and judgement. In this study, we address the issue whether, in market experiments, there is a tendency for anomalous behaviour to disappear or to be reduced as a consequence of market experience and feedback. We empirically test the validity of this assumption by running an auction market for the sale of both risky and uncertain prospects. We compare bidding behaviour and prices in market-like settings with valuations obtained from individual pricing tasks. We conclude that, with the repetition of the market experience, there is a tendency for subjective expected utility to perform better. However, economists' general assumption that, in laboratory experiments, poor performance of SEU is due to the lack of financial incentives or to the lack of market-like settings is by no means supported by our data