Partisans misperceive and are influenced by dynamic norms

Abstract Perceptions of social norms, and how those norms change over time, play a central role in shaping how people understand and respond to political divides. We developed and iteratively refined dynamic‐norm messages about bipartisan attitude change to reduce divisive outparty perceptions and attitudes in a US context. We first identified real‐world issues that gained support over time among both Democrats and Republicans and were judged as believable. Study 1 documented systematic misperceptions of attitude change across a range of social issues and linked these misperceptions to colder outparty feelings. We then tested intervention messages that adapted standard static‐norm templates with the addition of information about change over time (dynamic norm; Study 2). This intervention increased expectations of future common ground but did not reliably improve downstream outparty attitudes. Next, we tested a refined intervention message that isolated dynamic norm information (Study 3). The refined dynamic norm message increased expected common ground and expected future feelings of belonging among the outparty and was associated with small but reliable increases in outparty warmth and positive outparty impressions relative to control. These results suggest that emphasizing trajectories of public opinion without highlighting current partisan gaps may be a useful strategy for reducing polarization.