The reciprocal relationship between social identity and adherence to group norms.

Previous research has focused on how social identification influences people's adherence to group norms, but has rarely considered how norm adherence might in turn influence how strongly people identify with the group. We proposed a reciprocal relationship between social identification and norm adherence that is shaped by the salience of the social identity in question. Drawing on data from a longitudinal field study of young people attending a mass gathering (N = 661, 1239 unique observations), we used cross-lagged panel modelling across five timepoints to test the reciprocal relationship between social identification with friends and anticipated adherence to perceived drinking norms among friends before (T0), during (T1-T3), and after (T4) the event. Greater social identification at T1 significantly predicted greater norm adherence at T2 which, in turn, predicted greater social identification at T3. These bidirectional effects were only significant during the mass gathering event, when the referent social identity was salient and thus relevant and meaningful in the social context. Findings indicate a complex interplay between social identity and norm adherence that is context dependent and evolves over time. Not only does social identity promote norm adherence but also adherence to those same norms can reinforce a sense of connection to the group.