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 study risk taking on behalf of others in an experiment on a large random sample. The decision makers in our experiment are facing high-powered incentives to increase the risk on behalf of others through hedged compensation contracts or with tournament incentives. Compared to a baseline...

We investigate the quality provision behavior and its implications for the occurrence of collusion in competitive health care markets where providers are assumed to be altruistic towards patients. For this, we employ a laboratory experiment with a health care market framing where subjects decide...

We investigate how group boundaries, and the economic environment surrounding groups, affect altruistic cooperation and punishment behavior. Our study uses experiments conducted with 525 officers in the Swiss Army, and exploits random assignment to platoons. We find that, without competition...

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