Give more tomorrow: Two field experiments on altruism and intertemporal choice

This paper conducts two natural field experiments to test inter-temporal choices in charitable giving by varying the timing of commitment and payment. Monthly donors were asked to increase their contributions (1) immediately, (2) in one month, (3) in two months. The results are consistent between the two field experiments; first, mean increases in donations are significantly higher when donors are asked to commit to future donations. Second, follow-up data shows that the treatment effect is persistent, making the strategy highly profitable to the charity. Finally, I provide evidence of heterogeneity in the response to different time lags, indicating differences in inter-temporal choices among donors.