We present three field experiments that probe the influence of choice architecture on the contributions of a total of 328 participants to real charities. In the first experiment, framing a one-time donation opportunity as an opt-out as opposed to opt-in decision significantly increases donations to an environmental non-profit. In the second experiment, an automatic donation mechanism is provided that allows subjects to self-select into an opt-out framing; when combined with incentive-neutral, social-norm supporting activities (cheap talk and voting), automatic donations sustain increased contributions over a ten-month study period to an HIV/AIDS-related charity. In the third experiment, we study the extent to which the mention of HIV/AIDS in the charity's informational material impacts the emotions and donations of potential donors. In this case the connection to HIV/AIDS does not elicit stigma, but we do find that changes in mood from exposure to the charity's informational material predict increased donations, and that donors experience an improved mood from donating. (C) 2016 Published by Elsevier Inc.