Conclusion
In this randomized, controlled survey experiment, we found that both large and small financial incentives may motivate U.S. adults to vaccinate against COVID-19. This study was designed to examine the psychological mechanism that can help explain whether a financial incentive will succeed or fail, and why. The findings are also relevant to ongoing debates about the relative merits of various policy proposals to increase vaccination rates. Critics of the proposed financial incentive policies for COVID-19 vaccination have warned that such payments, especially large ones, will have counterproductive psychological effects, particularly among racial and ethnic minorities and lower income groups [