We investigate the welfare effect of increasing competition in an anonymous two-sided matching market, where matched pairs play an infinitely repeated Prisoner's Dilemma. Higher matching efficiency is usually considered detrimental as it creates stronger incentives for defection. We point out,...

Social interactions predominantly take place under the shadow of the future. Previous literature explains cooperation in indefinitely repeated prisoner's dilemma as predominantly driven by self-interested strategic considerations. This paper provides a causal test of the importance of social...

This paper evaluates the impact of a sudden and unexpected nation-wide alcohol sales ban in South Africa. We find that this policy causally reduced injury-induced mortality in the country by at least 14% during the five weeks of the ban. We argue that this estimate constitutes a lower bound on...

On July 13, 2020 a complete nation-wide ban was placed on the sale and transport of alcohol in South Africa. This paper evaluates the impact of this sudden and unexpected five-week alcohol prohibition on mortality due to unnatural causes. We find that the policy reduced the number of unnatural...

Reanalyzing 12 experiments on the repeated prisoner's dilemma (PD), we robustly observe three distinct subject types: defectors, cautious cooperators and strong cooperators. The strategies used by these types are surprisingly stable across experiments and uncorrelated with treatment parameters,...