This study will investigate the relationship between face mask usage and cooperative behavior in the US population during the Covid-19 pandemic. Social preferences are assumed to be one of the main determining factors of face mask usage. However, the decision to wear a face mask in public could also signal the wearer’s latent political identity, subsequently altering other’s perception of the wearer’s willingness to cooperate. We investigate the bi-directional relationship between these two variables in a randomized online survey experiment.