Ambiguity refers to a decision situation under uncertainty when there is incomplete information about the likelihood of events. Different formal models of this notion have been developed with differing implications about the representation of ambiguity and ambiguity aversion.

This paper shows that, for CEU preferences, the axioms consquentialism, state independence and conditional certainty equivalent consistency under updating characterise a family of capacities, called Genralised Neo-Additive Capacities (GNAC). This family contains as special cases among others...

We present a non-technical account of ambiguity in strategic games and show how it may be applied to economics and social sciences. Optimistic and pessimistic responses to ambiguity are formally modelled. We show that pessimism has the effect of increasing (decreasing) equilibrium prices under...

We study the impact of ambiguity on two alternative institutions of financial intermediation in an economy where consumers face uncertain liquidity needs. The ambiguity the consumers experience is modeled by the degree of confidence in their additive beliefs. We analyze the optimal liquidity...

As illustrated by the famous Ellsberg paradox, many subjects prefer to bet on events with known rather than with unknown probabilities, i.e., they are ambiguity averse. In an experiment, we examine subjects’ choices when there is an additional source of ambiguity, namely, when they do not know...

Goeree & Holt (2001) observe that, for some parameter values, Nash equilibrium provides good predictions for actual behaviour in experiments. For other payoff parameters, however, actual behaviour deviates consistently from that predicted by Nash equilibria. They attribute the robust deviations...

In this paper, we consider a decision-maker who tries to learn the distribution of outcomes from previously observed cases. For each observed sequence of cases the decision-maker predicts a set of priors expressing his beliefs about the underlying probability distribution. We impose a version of...

Least-Unmatched Price Auctions have become a popular format of TV and radio shows. Increasingly, they are also applied in internet trading. In these auctions the lowest single (unique) bid wins. We analyze the game-theoretic solution of least unmatched price auctions when prize, bidding cost and...

In this paper we consider the effect of ambiguity on the private provision of public goods. Equilibrium is shown to exist and be unique. We examine how provision of the public good changes as the size of the population increases. We show that when there is uncertainty there may be less...

In this paper, we study choice under uncertainty with belief functions on a set of outcomes as objects of choice. Belief functions describe what is objectively known about the probabilities of outcomes. We assume that decision makers have preferences over belief functions that reflect both their...