Using information on students’ past participation in economic experiments, we analyze whether behavior in public goods games is affected by experience and history. We find that: on average, the amount subjects contribute and expect others to contribute decreases with experience; at the individual level, the proportion of unconditional cooperators decreases with experience, while the proportion of selfish people increases. Finally, history influences behavior less than experience. Researchers are urged to control for subjects’ experience and history to improve the external validity (...) and replicability of results. (shrink)