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...

We report evidence of an endowment effect for risk, extending previous results to the popular paired-choice lottery setting. Specifically, we observe a distribution of revealed preferences consistent with risk aversion that diminishes in endowed variance, although the effect is considerably...

We refine the understanding of individual preferences across social lotteries, whereby the payoffs of a pair of subjects are exposed to random shocks. We find that aggregate behavior is ex-post and ex-ante inequality averse, but also that there is a wide variety of individual preferences and...