Megastudy testing 25 treatments to reduce antidemocratic attitudes and partisan animosity.

Scholars warn that partisan divisions in the mass public threaten the health of American democracy. We conducted a megastudy ( n = 32,059 participants) testing 25 treatments designed by academics and practitioners to reduce Americans' partisan animosity and antidemocratic attitudes. We find that many treatments reduced partisan animosity, most strongly by highlighting relatable sympathetic individuals with different political beliefs or by emphasizing common identities shared by rival partisans. We also identify several treatments that reduced support for undemocratic practices-most strongly by correcting misperceptions of rival partisans' views or highlighting the threat of democratic collapse-which shows that antidemocratic attitudes are not intractable. Taken together, the study's findings identify promising general strategies for reducing partisan division and improving democratic attitudes, shedding theoretical light on challenges facing American democracy.