Although experiments are the gold standard for establishing causality, several threats can
undermine the internal validity of experimental findings. In this article, we first discuss these …

Why should you help a competitor? Why should you contribute to the public good if free
riders reap the benefits of your generosity? Cooperation in a competitive world is a …

Combining evolutionary models with behavioral experiments can generate powerful insights
into the evolution of human behavior. The emergence of online labor markets such as …

A growing experimental literature studies the determinants of cooperation in infinitely
repeated games, tests different predictions of the theory, and suggests an empirical solution …

What explains variability in norms of cooperation across organizations and cultures? One
answer comes from the tendency of individuals to internalize typically successful behaviors …

We study the complexity of rules by paying experimental subjects to implement a series of
algorithms and then eliciting their willingness-to-pay to avoid implementing them again in …

The evolution of cooperation in network-structured populations has been a major focus of
theoretical work in recent years. When players are embedded in fixed networks, cooperators …

We study the experimental play of the repeated prisoner's dilemma when intended actions
are implemented with noise. In treatments where cooperation is an equilibrium, subjects …

The fundamental question of political theory, one that precedes all other questions about the
nature of political life, is why there is a state at all. Is human cooperation feasible without a …

The genetic evolution of altruism (ie, a behavior resulting in a net reduction of the survival
and/or reproduction of an actor to benefit a recipient) once perplexed biologists because it …