Incentives and Unintended Consequences: Spillover Effects in Food Choice
通过学校午餐室零食选择的田野实验，研究发现同伴选择葡萄的行为会正向促进其他孩子选择葡萄，但看到同伴因激励而选择葡萄则产生负向溢出效应，导致公开激励整体效果不显著。
Little is known about how peers influence the impact of incentives. We study how peers’ actions and incentives can lead to peer spillover effects. Using a field experiment on snack choice in the school lunchroom (choice of grapes versus cookies), we randomize who receives incentives, the fraction of peers incentivized, and whether or not it can be observed that peers’ choices are incentivized. We show that, while peers’ actions of picking grapes have a positive spillover effect on children’s take-up of grapes, seeing that peers are incentivized to pick grapes has a negative spillover effect on take-up. When incentivized choices are public, incentivizing all children to pick grapes, relative to incentivizing none, has no statistically significant effect on take-up, as the negative spillover offsets the positive impacts of incentives.