Studies on crowding out document that incentives sometimes backfire—decreasing motivation in prosocial tasks. In the present research, we demonstrated an additional channel through which incentives can be harmful. Incentivized advocates for a cause are perceived as less sincere than nonincentivized advocates and are ultimately less effective in persuading other people to donate. Further, the negative effects of incentives hold only when the incentives imply a selfish motive; advocates who are offered a matching incentive (i.e., who are told that the donations they successfully solicit will be matched), which is not incompatible with altruism, perform just as well as those who are not incentivized. Thus, incentives may affect prosocial outcomes in ways not previously investigated: by crowding out individuals’ sincerity of expression and thus their ability to gain support for a cause.

Charity could do the most good if every dollar donated went to causes that produced the greatest welfare gains. In line with this proposition, the effective-altruism movement seeks to provide individuals with information regarding the effectiveness of charities in hopes that they will contribute to organizations that maximize the social return of their donation. In this research, we investigated the extent to which presenting effectiveness information leads people to choose more effective charities. We found that even when effectiveness information is made easily comparable across options, it has a limited impact on choice. Specifically, people frequently choose less effective charity options when those options represent more subjectively preferred causes. In contrast to making a personal donation decision, outcome metrics are used to a much greater extent when choosing financial investments and when allocating aid resources as an agent of an organization. Implications for effective altruism are discussed.