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,...

When do we cooperate and why? This question concerns one of the most persistent divides between "theory and practice", between predictions from game theory and results from experimental studies. For about 15 years, theoretical analyses predict completely-mixed "behavior" strategies, i.e....

Experimenters have to make theoretically irrelevant decisions concerning user interfaces and ordering or labeling of options. Such presentation decisions affect behavior and cause results to appear contradictory across experiments, obstructing utility estimation and policy recommendations. The...

Overbidding in auctions has been attributed to e.g. risk aversion, loser regret, level-k, and cursedness, relying on varying identifying assumptions. I argue that "type projection" organizes these findings and largely captures observed behavior. Type projection formally models that people tend...

Why do people give when asked, but prefer not to be asked, and even take when possible? We show that standard behavioral axioms including separability, narrow bracketing, and scaling invariance predict these seemingly inconsistent observations. Specifically, these axioms imply that...