Charities are competing as never before for consumers' donations. Simply asking individuals what influences their donation decisions may not reveal true causal factors. Social-desirability pressures may prompt potential donors to respond with answers that make them look good, instead of with factors that truly influence their behavior. In two experiments, subjects pledged lower amounts to the same charity when information about the organization's director and/or spouse reinforced a negative stereotype for the gender of those subjects. The manipulated variables were neither identified as important in pretests nor acknowledged by subjects in the experiments. The results of a final study suggest that peer interpretation research techniques can help to more fully reveal factors relevant to donation behavior. These research findings suggest that charities must be aware of social-desirability issues when selecting content for their advertisements. © 2000 John Wiley & Sons, Inc.