When 3 + 1 > 4: Gift Structure and Reciprocity in the Field
通过现场实验发现，单纯提高工资不会提升生产率，但将部分工资作为意外礼物发放能显著提高员工在岗期间的生产率，其效果与增雇工人相当。
Do higher wages elicit reciprocity and lead to increased productivity? In a field experiment with 266 employees, we find that paying higher wages, per se, does not have a discernible effect on productivity in a context with no future employment opportunities. However, structuring a portion of the wage as a clear and unexpected gift—by offering an unconditional raise after the employee has accepted the contract—leads to higher productivity for the duration of the job. Gifts are roughly as efficient as hiring more workers. This paper was accepted by Uri Gneezy, behavioral economics.