Experience in public goods experiments

We use information on students´ past participation in economic experiments, as stored in our database, to analyze whether behavior in public goods games is affected by experience (i.e., previous participation in social dilemma-type experiments) and history (i.e., participation in experiments of a different class than the social dilemma). We have three main results. First, at the aggregate level, the amount subjects contribute and expect others to contribute decrease with experience. Second, a mixture model reveals that the proportion of unconditional cooperators decreases with experience, while that of selfish individuals increases. Finally, history also influences behavior, although to a lesser extent than experience. Our findings have important methodological implications for researchers, who are urged to control for subjects´ experience and history in their experiments if they want to improve the external validity and replicability of their results.