Regional variation in social norm nudges.

Public support is crucial for the effectiveness of ambitious climate policies, and social norm interventions have been proven effective in fostering support. An open question is which norms should be communicated if support and estimated support for climate policies differ substantially between regions. In two studies, we investigate whether individuals accurately assess the existing support and then explore the impact of national and regional norms on public support. Our results show that the norm on climate policy support is generally misperceived, i.e., the norm is higher than expected. This misperception increases with policy ambition and varies substantially between sub-national regions. Information about the national norm increases support, mainly in regions with below or above-average support. In contrast, interventions with regional norms are ineffective and even backfire in low-support regions. This demonstrates that norm nudges need to consider the regional aspects of the reference and target groups.