This paper studies the evolution of both characteristics of reciprocity - the willingness to reward friendly behavior and the willingness to punish hostile behavior. Firstly, preferences for rewarding as well as preferences for punishing can survive evolution provided individuals interact within...

I study the incentives of Cournot duopolists to share their technologies with their competitor in markets where intellectual property rights are absent and imitation is costless. The trade-off between a signaling effect and an expropriation effect determines the technology-sharing incentives. In...

We investigate a setting in which members of a population, bifurcated into a majority and a minority, transact with randomly matched partners. All members are uniformly altruistic, and each transaction can be carried out cooperatively or through a market mechanism, with cooperative transactions...

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.

I study attitudes towards risk taking in cases where a person relates to others positively, namely altruistically. This study is needed because it is unclear how altruism influences the inclination of an altruistic person to take risks. Will this person's risk-taking behavior differ if the...

The purpose of this paper is to provide a general proposition of the relationship between altruism and risk taking. As explained in the body of the paper, we diverge from a result reported in Stark et al. (2022) and provide an expansion and a generalization of a preliminary result reported in...

We offer a game-theoretic proof of Hamilton's rule for the spread of altruism. For a simple case of siblings, we show that the rule can be derived as the outcome of a one-shot prisoner's dilemma game between siblings. -- evolution of altruism ; Hamilton's rule ; one-shot prisoner's dilemma game

We examine two types of altruism and their implications for voluntary giving. Philanthropists are altruists who wish to enhance the well-being of others, while individuals with merit-good preferences only wish to further the consumption of certain merit goods by others. Philanthropic donors...