I would donate, but others won’t follow

The study examined organ donation preferences and perceived descriptive social norms under presumed consent for organ donation, a public policy proposed to address low organ donation rates in Serbia. Conducted as an online between-subjects experiment with students in Serbia, the research included two hypothetical organ donation conditions: opt-in (explicit consent) and optout (presumed consent). The opt-out default significantly increased willingness to donate but did not affect assumptions about others’ preferences under the same default. This finding suggests that perceived descriptive social norms may hinder the opt-out default’s effect on actual organ donation rates. Additionally, it implies that other potential mediating mechanisms, besides descriptive social norms, may be more significant drivers of the effect of opt-out defaults on donation intentions.