Using a unique field experiment we show that prompts to leave money to charity during the will-making process substantially increase the probability of making a bequest. Asking if the donor wants to leave money to charity doubles the proportion
making a bequest; adding emotional and social cues trebles it. The responses are strongest among childless people. We compare the effects of the prompts to the effect of an estates tax. Our results suggest that both economic and non-pecuniary
incentives similarly affect whether people leave money to charity, but are less effective where people have strong preferences for other bequests.