Coins Are Cold and Cards Are Caring: The Effect of Pregiving Incentives on Charity Perceptions, Relationship Norms, and Donation Behavior
通过七项研究（含两项大规模实地实验），发现慈善募捐信中附赠小额货币（如硬币）或非货币（如贺卡）激励的效果取决于组织目标：货币激励提高拆信率和新捐赠者响应率，但降低平均捐赠额，因其激活交换规范而非共有规范。
Charities often include low-value monetary (e.g., coins) and nonmonetary (e.g., greeting cards) pregiving incentives (PGIs) in their donation request letters. Yet little is known about how donors respond to this marketing strategy. In seven studies, including two large-scale field experiments, the authors demonstrate that the effectiveness of PGIs depends on the organization’s goals. People are more likely to open and read a letter containing a monetary PGI (vs. a nonmonetary PGI or no PGI). In addition, monetary PGIs increase response rates in donor acquisition campaigns. However, the return on investment for direct mail campaigns drops significantly when PGIs are included. Furthermore, average donations for appeals with a nonmonetary PGI or no PGI are similar, while those with a monetary PGI are actually lower than when a nonmonetary PGI or no PGI is included. This is because monetary PGIs increase exchange norms while decreasing communal norms. This effect remains significant when accounting for alternative explanations such as manipulative intent and the anchoring and adjustment heuristic.