Social Relationships and the Moderating Role of Prior Bullying Experiences in Bystander Behaviors Among Later Adolescents.

Bullying is deeply embedded in adolescents' social ecologies and has enduring developmental consequences. Accordingly, the quality of social relationships, together with adolescents' prior bullying experiences, may play a critical role in shaping bystander behaviors. This study examined how peer, parent-child, and teacher-student relationships were associated with adolescents' bystander behaviors (i.e., defending, pro-bullying, passive bystanding), and whether these associations are moderated by prior experiences of bullying perpetration and victimization. Using nationally representative data from the Korean Children and Youth Panel Survey (12th grade, N = 2,224), multilevel modeling was employed to examine the main and interactive effects of social relationships and bullying experiences on bystander behaviors, accounting for the clustering of adolescents within schools. Peer relationship quality was uniquely associated with defending (β = .08, p = .026), whereas all types of higher-quality social relationships were associated with lower pro-bullying (peer: β = -.17, p < .001; parent-child: β = -.29, p < .001; teacher-student: β = -.07, p = .020). In contrast, higher-quality peer relationships were related to greater passive bystanding only among adolescents with bullying perpetration experience (β = .16, p = .006), and stronger parent-child relationships were associated with greater passive bystanding among those without bullying victimization experience (β = .15, p = .003). These findings reveal that the prosocial potential of social relationships is not unconditional: while peer, parent-child, and teacher-student relationships were consistently associated with lower pro-bullying and peer relationships were associated with greater defending, their associations with passive bystanding were contingent upon adolescents' prior bullying histories. Effective prevention therefore requires simultaneous assessment of relationship quality and bullying history, as these two dimensions appear to jointly shape whether relational resources are associated with passive bystanding or pro-bullying reinforcement.