Social Preferences and the Response to Incentives: Evidence from Personnel Data*
通过比较计件工资和相对激励下的工人生产率，发现工人会部分内化相对激励对同事的负外部性，尤其当与朋友一起工作时，这揭示了社会偏好的存在。
We present evidence on whether workers have social preferences by comparing workers' productivity under relative incentives, where individual effort imposes a negative externality on others, to their productivity under piece rates, where it does not. We find that the productivity of the average worker is at least 50 percent higher under piece rates than under relative incentives. We show that this is due to workers partially internalizing the negative externality their effort imposes on others under relative incentives, especially when working alongside their friends. Under piece rates, the relationship among workers does not affect productivity. Further analysis reveals that workers internalize the externality only when they can monitor others and be monitored. This rules out pure altruism as the underlying motive of workers' behavior.