This paper considers a dynamic model of the evolution of open source software projects, focusing on the evolution of quality, contributing programmers, and users who contribute customer support to other users. Programmers who have used open source software are motivated by reciprocal altruism to...

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...

Transplants of donated stem cells save the lives of many patients with blood diseases. Donation is somewhat painful, but rarely has lasting adverse effects. Patients can accept transplants only from donors with compatible immune systems. Those lacking a sibling match must seek donations from the...

Transplants of donated stem cells save the lives of many patients with blood diseases. Donation is somewhat painful, but rarely has lasting adverse effects. Patients can accept transplants only from donors with compatible immune systems. Those lacking a sibling match must seek donations from the...

In the policy debate, intellectual property is often justified by what seems to be a straightforward argument: if innovators are not protected against others appropriating their ideas, incentives for innovation are suboptimally low. Now in most industries for most potential users, appropriating...

In the policy debate, intellectual property is often justified by what seems to be a straightforward argument: if innovators are not protected against others appropriating their ideas, incentives for innovation are suboptimally low. Now in most industries for most potential users, appropriating...

In the Solidarity Game (Selten and Ockenfels, 1998), two "rich" persons can support a "poor" one. A strong positive correlation between one rich person's solidarity contribution and his expected contribution of the other is observed. This paper investigates the causality behind this correlation....

This paper surveys the literature on group selection. I describe the early contributions and the group selection controversy. I also describe the main approaches to group selection in the recent literature; fixation, assortative group formation, and reproductive externalities. -- Altruism ; spite...

This paper revisits the question of framing and the provision of public goods. It also addresses the question, is giving in Dictator Games an expression of altruism or an artefact of experimentation? What is unique about this paper is that we employ a real donationʺ lab experiment in a...