When allies join the fight: How joint collective action shapes social change and intergroup relations

Abstract

Over the past decade, a global rise in protests and social movements has held promise for advancing social change, while also introducing new societal tensions. The current research examined the effects of joint collective action involving both advantaged and disadvantaged group members, compared to collective action by the disadvantaged group alone, on support for social change and intergroup polarisation. Across four studies (two pilot and two preregistered; N = 1707), joint collective action (vs. collective action by the disadvantaged) reliably fostered advantaged group members' support for social change. Among disadvantaged group members, a consistent pattern emerged across studies: joint collective action supported—but not led—by advantaged allies indirectly enhanced support for change and reduced polarisation through increased perceptions of respect, but showed no direct effects on these outcomes. These findings highlight the promise of joint collective action in promoting both social equality and cohesion, while also emphasising the need to address power asymmetries and respect disadvantaged groups' agency in the process.