Introduction
During the SARS-CoV-2 pandemic, proposals to pay people for vaccinating [When explaining why they believe financial incentives would decrease the number of Americans who would want to vaccinate, experts have offered various reasons. For example, some experts contend that financial incentives are likely to give the impression that the vaccine lacks inherent value [On the other hand, financial incentives could increase COVID-19 vaccination rates by strengthening vaccine motivation. Financial incentives have had mixed effects in studies designed to increase motivation for various health-related behaviors, such as attending medical appointments, exercising, and donating blood; some of these studies have found financial incentives to be effective whereas others found them to be ineffective or even counterproductive [Because critics have argued that policies offering relatively large payment amounts are especially likely to decrease interest in vaccination [Studies in the U.S. have begun to examine the effects of financial incentive policies on COVID-19 vaccine motivation, but they have lacked comparisons between relatively small and large payment amounts. (For an exception, see Fishman et al., 2022, which focuses on a different study population [Our research also contributes to the literature by focusing on the malleable, psychological mechanism that predicts future behavior, including COVID-19 vaccination [Furthermore, when the study outcome is limited to vaccination behavior, the effects on the psychological mechanism can be obscured [Critics have warned that financial incentives are most likely to decrease interest in vaccination among those populations that are already hesitant [