When Charities Compete: A Laboratory Experiment with Simultaneous Public Goods

What happens when charities compete? We begin to answer this question through a laboratory experiment in which subjects play two public goods games simultaneously. We systematically vary the incentives for contributing in one of the games - investigating the effects of recognition, a bonus conditional on contributing, and non-monetary sanctions - and measure the effect on contributions in both games. Monetary incentives in the form of conditional bonuses increase contributions, even when two games are played simultaneously. However, non-monetary incentives such as recognition and sanctions are less effective than in related literature on games played in isolation. Moreover, we find mixed evidence of the spillover effect of treatment on the un-treated games - bonuses increase contributions initially, recognition decreases contributions, and sanctions have no effect.