Vaccination poses a social contract

Research article by Robert Böhm, The Department of Psychology, University of Copenhagen, and Lars Korn, Nicholas W. Meier, and Cornelia Betsch, Media and Communication Science, University of Erfurt.

The COVID-19 pandemic shows what many people have forgotten when it comes to other diseases, such as measles: we are able to control and even eliminate infectious diseases by vaccination – provided many people contribute to this by getting vaccinated. In 2019 the German Ethics Council argued that vaccination therefore poses a social contract. “We were interested in whether people indeed act upon this social contract. Do people feel a moral obligation to get vaccinated? And what happens if some people violate this moral principle?” says German PhD student Lars Korn about the studies conducted by psychologists from the Universities of Erfurt and Copenhagen, funded by the German Research Foundation. The results have now been published in PNAS (Proceedings of the National Academy of Sciences).

To investigate the consequences of moral obligations related to vaccination, more than 2,200 participants engaged in an interactive vaccination game. Afterwards, they were asked to allocate money to other persons who did either decide in favor of or against vaccination. The idea was that if vaccination is considered moral behavior, not getting vaccinated should be punished by allocating less money to those people.

The results were clear: Participants who were vaccinated rewarded vaccinated others by allocating them more money and punished unvaccinated others by allocating them less money. In contrast, unvaccinated participants didn’t allocate different amounts of money to vaccinated versus unvaccinated others. The researchers therefore concluded that vaccination poses a social contract.

The results also have implications for the current COVID-19 pandemic: “Cooperation is important to curb the spread of the disease. For instance, many facial masks don’t protect the wearer but others. Hence, people who don’t wear masks could be ‘sanctioned’ by mask wearers, either directly or indirectly by scowling at them.” says Robert Böhm, Professor at the Department of Psychology/SODAS and co-author of the paper. Such social pressures resulting from a psychological social contract could enforce cooperative behaviors but could also increase societal polarization.

Find the full research article on the Proceedings of the National Academy of Sciences' website.