Abstract What triggers giving? We explore this in a randomized natural field experiment during the Salvation Army's annual campaign. Solicitors were at one or both of two main entrances to a supermarket, making the solicitation either easy or difficult to avoid. Additionally, solicitors were either silent, or asked "please give" to passersby. We observed over 17,000 passings over four days, and found dramatic avoidance of the solicitors, but only during a direct ask. Furthermore, asking increased donations 75%. Across all conditions, seeking the solicitor was exceedingly rare. The results do not support static views of altruism, such as inequity aversion, and instead highlight the importance of social cues and psychological f...