We introduce and analyze three definitions of equilibrium for finite extensive games with imperfect information and ambiguity averse players. In a setting where players' preferences are represented by maxmin expected utility, as characterized in Gilboa and Schmeidler (1989), our definitions...

We examine repeated Cournot oligopolies when there is uncertainty about the number of players. Already in the static game, such uncertainty can imply outputs above Nash. For the repeated game, we argue that the uncertainty may lead to a novel strategy, based on a notion of limited depth of...

The paper studies when efficient allocations are implementable via coalition-proof mechanisms. When ambiguous mechanisms are allowed and agents are maxmin expected utility maximizers, we prove that all efficient allocations are implementable via interim coalition incentive compatible mechanisms...

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 provide an evolutionary foundation to evidence that in some situations humans maintain optimistic or pessimistic attitudes towards uncertainty and are ignorant to relevant aspects of the environment. Players in strategic games face Knightian uncertainty about opponents' actions and maximize...

We provide an evolutionary foundation to evidence that in some situations humans maintain either optimistic or pessimistic attitudes towards uncertainty and are ignorant to relevant aspects of the environment. Players in strategic games face Knightian uncertainty about opponents' actions and...

I investigate the decision problem of a player in a game of incomplete information who faces uncertainty about the other players' strategies. I propose a new decision criterion which works in two steps. First, I assume common knowledge of rationality and eliminate all strategies which are not...

This paper proposes that the ambiguity reflected by a set of priors remains unchanged when the set is translated within the probability simplex, i.e. ambiguity is location invariant. This unifies and generalises numerous influential definitions of ambiguity in the literature. Location invariance...

Goeree and Holt (2001) experimentally study a number of games. In each case they initially find strong support for Nash equilibrium, however by changing an apparently irrelevant parameter they find results which contradict Nash equilibrium. In this paper, we study the five normal form games from...

The ultimatum heuristic is a decision-making tendency discernible in graphical plots of mixed-motive noncooperative games. As such, it can serve also as a solution approach, backsolving, predicting and explaining outcomes better than the mainstay Nash equilibrium concept whenever data for the...