Disposition, history and contributions in public goods experiments

Novel voluntary contribution mechanism experiments are used to investigate how individuals’ experience (history) and cooperative disposition and interact. We find that a subject's initial public contribution is a useful measure of cooperative disposition. History effects are isolated by comparing treatments with random group assignment to treatments where subjects are grouped based on their contributions. The latter treatment increases the frequency with which cooperative subjects interact. We trace the familiar decay in public good contributions over rounds, which are observed under random grouping, to reductions in contributions by those with cooperative dispositions when they are forced to repeatedly interact with free-riders.