Working title: Face-Masks and Vaccines as a Social Dilemma (: How to avoid free-riders)

In 2020, the SARS-COV-2 pandemic forced countries across the world to enforce measures such as wearing face masks. An important aspect of mask-wearing is that masks mainly protect other individuals, while causing a discomfort for the wearer. Therefore, the motivation to comply with such rules is altruism and mutual trust. Available vaccines leading to herd immunity might be the end of such regulations, but bring about different benefits and costs depending on how many people engage. The present online study employs scenarios inspired by game theory to obtain information about determinants of mask-wearing and vaccinating behaviors. Participants will be asked to decide if they would wear a mask in different situations, e.g. with family members or strangers, where the prior knowledge provided about the interaction partner is modulated. Further, they are asked to decide whether they get vaccinated in situations where perceived costs (side effects/monetary) and perceived herd immunity/social pressure are manipulated. We would like to obtain a behavioral measure of altruism by offering a monetary reward, that can either be transferred directly to the participant (low altruism) or a beneficial organization (high altruism) (!only if funding is granted!). Validated questionnaires allow to control for other factors, such as perceived vulnerability to disease, empathy and altruism. The cross-cultural approach will help to find generalizable conclusions that can help to shape informed health policies across Europe.