People in less dense towns tend to get vaccinated more often to protect others compared to people in more dense cities

Jung, H., & Albarracín, D. (2021). Concerns for others increases the likelihood of vaccination against influenza and COVID-19 more in sparsely rather than densely populated areas. Proceedings of the National Academy of Sciences, 118(1). https://doi.org/10.1073/pnas.2007538118

Haesung Jung, PhD, is a Psychology postdoctoral research associate at the University of Pennsylvania (though this was published when she was a postdoctoral research associate at the University of Illinois, Urbana-Champaign).

Dolores Albarracin, PhD, is a Professor of Psychology at the University of Pennsylvania (but she was also at the University of Illinois, Urbana-Champaign when this was published).