Group Identity and Pro-Environmental Behavior in Public Settings: Using Identity-based Nudges to Enhance Recycling in the Field

Recent years have seen progress in encouraging pro-environmental behavior at home, but promoting pro-environmental practices in public settings remains a challenge. This study leverages social identity theory to explore how group identities can be harnessed to encourage pro-environmental behavior in public settings. To achieve this, we focused on football supporters of away teams during 14 stadium football games—a setting that allows for the examination of group identity appeals across multiple distinct groups. Conducting a field experiment (N = 5,712) with a Premier Division Norwegian football club during the full 2023 football season, we found that an ingroup appeal combined with an ingroup gamification nudge tripled the rate of pro-environmental behavior among visiting supporters. A follow-up survey experiment (N = 1,813) revealed that the effectiveness of ingroup-based appeals is partly driven by supporters’ desire to contribute to their club’s success and their perception of the appeal’s effectiveness. Two post-test experiments with UK Premier League supporters (combined N = 2,044) replicated these findings, further emphasizing the superiority of ingroup appeals, particularly when combined with gamification. Collectively, this research bridges the gap between social identity theory and pro-environmental behavior, offering evidence-based strategies for leveraging group identities to promote pro-environmental actions in public settings.