The literature on International Environmental Agreements (IEAs) predicts a rather low number of signatories to an IEA. This is in sharp contrast to empirical evidence. As experimental economics provides some evidence for more complex human behavior, extending the theory of IEAs to a broader...

When providing public goods through voluntary contributions, a donor may introduce unilateral matching in order to reduce underprovision of the public good and thus inefficiency. By itself, however, matching benefits the donor but harms the recipient. We apply Cornes and Hartley's aggregative...