Altruists and envious people who meet in contests are symbionts. They do better than a population of narrowly rational individuals. If there are only altruists and envious individuals, a particular mixture of altruists and envious individuals is evolutionarily stable.

We examine whether the "Level-k" model of strategic behavior generates reliable cross-game predictions within an individual. We find no correlation in subjects' estimated levels of reasoning across two families of games. Furthermore, estimating a higher level for Ann than Bob in one family of...

We investigate whether there is a link between conditional cooperation and betrayal aversion. We use a public goods game to classify subjects by type of contribution preference and by belief about the contributions of others; and we measure betrayal aversion for different categories of subject....

Extensive research in economics explores generosity in monetary allocations. However, generosity often involves the allocation of non-monetary goods or experiences. Existing evidence suggests that generosity may be higher in such contexts, though no direct comparison exists. Here, we compare...

This paper explores the reluctance of men (women) to acknowledge or recognise the work, comments, and claims of new ideas by other men (women) via widespread and intense demonstrations of indifference. Instances like desk rejections by journals by not allowing papers to reach a review stage,...

We provide experimental evidence on the emergence of redistributive societies. Individuals first vote on redistribution by feet and then learn their productivity and invest. We vary the individuals ́information about their productivities at the time when they choose a distribution rule and find...

We study how punishment influences conditional cooperation. We ask two questions: 1) how does conditional cooperation change if a subject can be punished and 2) how does conditional cooperation change if a subject has the power to punish others. In particular, we disentangle the decision to be a...