Die Dis cus si on Pape rs die nen einer mög lichst schnel len Ver brei tung von neue ren For schungs arbei ten des ZEW. Die Bei trä ge lie gen in allei ni ger Ver ant wor tung der Auto ren und stel len nicht not wen di ger wei se die Mei nung des ZEW dar.Dis cus si on Papers are inten ded to make results of ZEW research prompt ly avai la ble to other eco no mists in order to encou ra ge dis cus si on and sug gesti ons for revi si ons. The aut hors are sole ly respon si ble for the con tents which do not neces sa ri ly repre sent the opi ni on of the ZEW. Abstract: Voting for Burden Sharing Rules in Public Goods GamesIn this experiment, we endogenize the choice of which contribution scheme is implemented in a public goods game. We investigate three rule-based contribution schemes. In a first step, players agree on a common group provision level using the principle of the smallest common denominator. Subsequently, this group investment is allocated according to a specific rule to individual minimum contributions. The game is implemented either as a Single-or a MultiPhase Game. In the Single-Phase Game, the contribution schemes are exogenously implemented. In the Multi-Phase Game, we let subjects vote on the rule-based contribution schemes. If a scheme obtains a sufficient majority it is implemented. In case no sufficient majority is reached, subjects have to make their contributions to the public good using the voluntary contribution mechanism (VCM). Our results suggest that the endogenous choice of a contribution scheme has an impact on the level of contributions. In case of a rule-based contribution scheme which equalizes payoffs, contributions are higher if subjects choose the scheme than in case the scheme is implemented exogenously. In contrast, contributions are higher if the VCM is implemented exogenously than in case a sufficient majority cannot be obtained and, therefore, subjects have to play the VCM.

A growing experimental literature studies the endogenous choice of institutions to solve cooperation problems arising in prisoners' dilemmas, public goods games, and common pool resource games. Participants in these experiments have the opportunity to influence the rules of the game before they play the game. In this paper, we review the experimental literature of the last 20 years on the choice of institutions and describe what has been learned about the quality and the determinants of institutional choice. Cooperative subjects and subjects with optimistic beliefs about others often vote in favor of the institution. Almost all institutions improve cooperation if they are implemented, but they are not always implemented by the players. Institutional costs, remaining free-riding incentives, and a lack of learning opportunities are identified as the most important barriers. Unresolved cooperation problems, like global climate change, are often characterized by these barriers. The experimental results also show that cooperation tends to be higher under endogenously chosen institutions than exogenously imposed institutions. However, a significant share of players fails to implement the institution and they often perform poorly, which is why we cannot conclude that letting people choose is better than enforcing institutions from outside.

In this paper, we investigate whether dynamic incentive schemes lead to a ratchet effect in a social dilemma. We test whether subjects strategically restrict their contribution levels at the beginning of a cumulative public goods game in order to avoid high obligations in the future and how this affects efficiency. The incentive schemes prescribe that individual contributions have to be at least as high as, or strictly higher than, contributions in the previous period. We observe a substantial and statistically significant ratchet effect. Participants reduce their public good contribution levels at the beginning of the game, anticipating that higher contributions imply higher minimum contribution levels in the future, which increases the risk of being exploited by freeriders. While the dynamic incentive schemes lead to increasing contribution levels over the course of the game, this increase is not strong enough to compensate the efficiency losses at the beginning.

We study spatially differentiated competition between charities by partnering with two foodbanks in two neighboring cities to conduct a field experiment with roughly 350 donation appeals. We induce spatial differentiation by varying the observability of charities' location such that each donor faces a socially close 'home' and a distant 'away' charity. We find that spatially differentiated competition is characterized by sorting, crowding-in, and an absence of spillovers: Donors sort themselves by distance; fundraising (through matching) for one charity raises checkbook giving to that charity, irrespective of distance; but checkbook giving to the unmatched charity is not affected. For lead donors, this implies that the social distance between donors and charities is of limited strategic important. For spatially differentiated charities, matching 'home' donations maximizes overall charitable income. Across both charities, however, the additional funds raised fail to cover the cost of the match, despite harnessing social identity for giving.

I investigate if, how, and why the effect of a contribution rule in a public goods game depends on how it is implemented: endogenously chosen or externally imposed. The rule prescribes full contributions to the public good backed by a nondeterrent sanction for those who do not comply. My experimental design allows me to disentangle to what extent the effect of the contribution rule under democracy is driven by self-selection of treatments, information transmitted via the outcome of the referendum, and democracy per se. In case treatments are endogenously chosen via a democratic decision-making process, the contribution rule significantly increases contributions to the public good. However, democratic participation does not affect participants' contribution behavior directly, after controlling for self-selection of treatments and the information transmitted by voting.