Although in everyday life decisions about losses are prevalent (e.g., the climate crisis and the COVID-19 crisis), there is hardly any research on decisions in the loss domain. Therefore, we conducted online experiments with a sample of 672 participants (mostly students), using third-party punishment dictator games (DGs) in the loss domain to explore the impact of losses and punishment threats on the conformity to the fairness norm. Subjects in the treatment condition have to divide a loss of -10 € with the threat of a third-party punishment with different strengths (control: gains, no punishment). Overall, the statistical evidence seems rather weak, but when it comes to losses, subjects are more rational and straightforward with their words and deeds than with gains. Therefore, in the loss domain, subjects are more likely to believe that the fairness norm should be followed, and they subjectively perceive that the others do as well. Furthermore, although dictators' decisions are more selfish in the loss domain, dictators there react more strongly to the punishment threat by reducing their demands than in the gains domain. This holds as long as the punishment threat is strong enough, as judged from a rational perspective.
Keywords: dictator game; fairness; loss domain; punishment; social norms; third-party-punishment game.