Anomalous Behavior in Linear Public Goods Experiments: How Much and Why?

We report the results of voluntary contributions experiments where subjects are randomly assigned constant marginal rates of substitution between the public and the private good. These random assignments a.re changed after each decision period. The design allows us to measure the response functions of the players in much the same way that bidding functions can be measured in private good, sealed-bid auction experiments. The results are quite different from the results of others in environments with little or no heterogeneity. We see much more free riding, very little evidence of decay across periods, and only sparse evidence of anomalous behavior such as splitting, spite, and decay