ABSTRACT
Both private and public benefits result from vaccination for transmissible diseases, such as seasonal influenza, measles, and COVID-19. To help inform vaccination efforts for such diseases, we ask whether social preferences-concerns for the well-being of other people-influence one's decision regarding vaccination. We measure these social preferences for 549 online subjects: We give each subject $4 to play a public-good game and make contributions to public welfare. To the extent that one gets vaccinated out of concern for the health of others, contribution in this game is analogous to an individual's decision to obtain vaccination. We proxy vaccine demand with individuals' delay to initially vaccinate for COVID-19. We collect COVID-19 vaccination history separately to avoid experimenter-demand effects. We find a strong result: Contribution in the public-good game is associated with greater demand to voluntarily receive a first dose, and thus also to vaccinate earlier. Compared to a subject who contributes nothing, one who contributes the maximum ($4) is 48% more likely to obtain a first dose voluntarily in the four-month period that we study (April through August 2021). People who are more pro-social are indeed more likely to take a voluntary COVID-19 vaccination. We thus recommend further research on the use of pro-social preferences to help motivate individuals to vaccinate for transmissible diseases, such as the flu and HPV.
ABSTRACT
Background: Widespread vaccination is certainly a critical element in successfully fighting the COVID-19 pandemic. We apply theories of social identity to design targeted messaging to reduce vaccine hesitancy among groups with low vaccine uptake, such as African Americans and political conservatives. Methods: Participants. We conducted an online experiment from April 7 to 27, 2021, that oversampled Black, Latinx, conservative, and religious U.S. residents. We first solicited the vaccination status of over 10,000 individuals. Of the 4,609 individuals who reported being unvaccinated, 4,190 enrolled in our covariate-adaptive randomized trial.Interventions. We provided participants messages that presented the health risks of COVID-19 to oneself and others; they also received messages about the benefits of a COVID-19 vaccine and an endorsement by a celebrity. Messages were randomly tailored to each participant's identities-Black, Latinx, conservative, religious, or being a parent.Outcomes. Respondents reported their intent to obtain the vaccine for oneself and, if a parent, for one's child. Results: We report results for the 2,621 unvaccinated respondents who passed an incentivized manipulation check. We find no support for the hypothesis that customized messages or endorsers reduce vaccine hesitancy among our segments. A post hoc analysis finds evidence that a vaccine endorsement from Dr. Fauci reduces stated intent to vaccinate among conservatives. Conclusions: We find no evidence that tailoring public-health communication regarding COVID-19 vaccination for broad demographic groups would increase its effectiveness. We recommend further research on communicators and endorsers, as well as incentives.
ABSTRACT
Sustaining cooperation in social dilemmas is a fundamental objective in the social and biological sciences. Although providing a punishment option to community members in the public goods game (PGG) has been shown to effectively promote cooperation, this has some serious disadvantages; these include destruction of a society's physical resources as well as its overall social capital. A more efficient approach may be to instead employ a reward mechanism. We propose an endogenous reward mechanism that taxes the gross income of each round's PGG play and assigns the amount to a fund; each player then decides how to distribute his or her share of the fund as rewards to other members of the community. Our mechanism successfully reverses the decay trend and achieves a high level of contribution with budget-balanced rewards that require no external funding, an important condition for practical implementation. Simulations based on type-specific estimations indicate that the payoff-based conditional cooperation model explains the observed treatment effects well.
