This article examines the motivations behind charitable giving in the United States, where 90% of individuals donate money annually. The authors distinguish between two types of motivation: altruism (or warm glow) and social pressure. They design a field experiment to test these motivations through door-to-door fundraising campaigns for two charities: a local children's hospital and an out-of-state charity. The experiment includes treatments with and without a flyer on the doorknob, which informs households about the solicitation time, and an opt-out option. The results show that the flyer reduces the share of households opening the door by 9% to 25%, and the opt-out option further reduces giving by 28% to 42%, particularly for small donations. These findings suggest that social pressure is a significant factor in door-to-door giving. The authors estimate the welfare costs of social pressure, finding that door-to-door campaigns lower the utility of potential donors. They conclude that unsolicited fund-raising campaigns can lead to substantial welfare losses for donors and suggest that providing households with sorting or opt-out options can mitigate these losses.This article examines the motivations behind charitable giving in the United States, where 90% of individuals donate money annually. The authors distinguish between two types of motivation: altruism (or warm glow) and social pressure. They design a field experiment to test these motivations through door-to-door fundraising campaigns for two charities: a local children's hospital and an out-of-state charity. The experiment includes treatments with and without a flyer on the doorknob, which informs households about the solicitation time, and an opt-out option. The results show that the flyer reduces the share of households opening the door by 9% to 25%, and the opt-out option further reduces giving by 28% to 42%, particularly for small donations. These findings suggest that social pressure is a significant factor in door-to-door giving. The authors estimate the welfare costs of social pressure, finding that door-to-door campaigns lower the utility of potential donors. They conclude that unsolicited fund-raising campaigns can lead to substantial welfare losses for donors and suggest that providing households with sorting or opt-out options can mitigate these losses.