Vaccination and Discrimination : Experimental Evidence under the COVID-19 Pandemic

In this study, we conduct financially incentivized dictator games with the COVID-19 vaccinated and unvaccinated people in Japan (N=1,578), and ascertain their favorable or hostile attitudes toward each other, by using ingroup favoritism. We measure ingroup favoritism as the difference in the allocated amounts between to ingroup members with the same vaccination status and to outgroup members with a different status. Our analyses suggest that the vaccinated people behave more discriminately toward outgroup members, compared to the unvaccinated people. The vaccinated people show strong ingroup favoritism, which are shaped mainly by their outgroup bias of decreasing the money amount allocated to an unvaccinated pair, their outgroup member. In contrast, the unvaccinated people do not exhibit such the ingroup favoritism, on average. Their outgroup bias is found in the rather opposite direction of the hypothesis, and they tend to increase the amount to a vaccinated pair, their outgroup member. We find this tendency in particular from the unvaccinated who selected as their non-vaccination reason “I would like to get vaccinated if I could, but I cannot for health or other reasons.” Furthermore, we confirm significant associations between their ingroup favoritism and attitudes regarding the COVID-19 policies, suggesting that the biases would have some degree of social influence in the real world. This study’s findings can contribute to discovering how to smoothly build cooperative relationships between vaccinated and unvaccinated people under the current and future pandemics