costly, making cooperation more likely. We test this prediction with a laboratory experiment in which subjects first choose … those costs are arms-dependent, cooperation increases by nearly a third. …

We report data from public goods games showing that privately-implemented punishment reduces cooperation in relation to … a baseline treatment without punishment. When that same incentive is implemented publicly, however, cooperation is … sustained at significantly higher rates than in either the baseline or private punishment treatments. Our design ensures that …

We present evidence from a laboratory experiment showing that individuals who believe they were treated unfairly in an …