"Financial incentives for vaccination do not have negative unintended consequences," in Nature

 Here's a recent article in Nature whose title effectively summarizes its conclusions, and brings some evidence from RCTs to bear on the issue of whether financial incentives corrupt innate values:

Florian H. Schneider, Pol Campos-Mercade, Stephan Meier, Devin Pope, Erik Wengström & Armando N. Meier, "Financial incentives for vaccination do not have negative unintended consequences. Nature (2023). https://doi.org/10.1038/s41586-022-05512-4

Abstract: Financial incentives to encourage healthy and prosocial behaviours often trigger initial behavioural change1,2,3,4,5,6,7,8,9,10,11, but a large academic literature warns against using them12,13,14,15,16. Critics warn that financial incentives can crowd out prosocial motivations and reduce perceived safety and trust, thereby reducing healthy behaviours when no payments are offered and eroding morals more generally17,18,19,20,21,22,23,24. Here we report findings from a large-scale, pre-registered study in Sweden that causally measures the unintended consequences of offering financial incentives for taking the first dose of a COVID-19 vaccine. We use a unique combination of random exposure to financial incentives, population-wide administrative vaccination records and rich survey data. We find no negative consequences of financial incentives; we can reject even small negative impacts of offering financial incentives on future vaccination uptake, morals, trust and perceived safety. In a complementary study, we find that informing US residents about the existence of state incentive programmes also has no negative consequences. Our findings inform not only the academic debate on financial incentives for behaviour change but also policy-makers who consider using financial incentives to change behaviour.

"We exploit a randomized controlled trial (RCT) in the context of financial incentives for COVID-19 vaccination (P.C.-M. et al., unpublished, and ref. 5). Participants were offered payments of 200 Swedish krona (SEK; about US $24 at the time) for taking a first dose of a COVID-19 vaccine, which increased first-dose uptake by 4 percentage points 30 days after the trial (uptake remained higher even 3 months later). The RCT setting is ideal in that it allows us to compare individuals who were randomly offered financial incentives for vaccination with individuals who were not offered any financial incentives. We combine the RCT data with new Swedish administrative records for second-dose uptake and with rich, individual-level survey data.

...

"We complement our evidence from Sweden with evidence on the effects of large-scale incentive programmes implemented by US state governments. In a pre-registered study in the USA (n = 3,062), participants randomly assigned to the incentives condition received detailed information about their state’s COVID-19 vaccine incentive programme, whereas participants in the control condition did not receive this information. Because most of the participants were unaware that their state offered incentives for vaccination, this experimental design overcomes the identification problems by creating random variation in perceived exposure to incentives. In line with the evidence from Sweden, we find no negative impacts of being informed about incentive programmes on the willingness of participants to take a further dose"