Longitudinal associations among social relationship closeness, cyberbullying victimization experience, and bystander defending behavior in cyberbullying: a random intercept cross-lagged panel model

When cyberbullying incidents occur in public online environments, bystander interventions can alter the progression of these events. Defending behavior serves as a pivotal factor in resolving cyberbullying, yet its triggering mechanisms and behavioral outcomes remain underexplored. Grounded in social bond theory, this study conducted a three-wave longitudinal survey over six months with 1176 university students. A random intercept cross-lagged model was employed to examine the longitudinal relationships among bystanders’ cyberbullying victimization experiences, social relationship closeness, and defending behavior. The findings suggest that bystander intervention reflects a balance between personal interests, the well-being of others, and collective benefits. Over time, bystanders’ prior victimization experience positively influenced their defending behavior, and a lagged effect emerged between defending behavior and social relationship closeness. These results highlight the importance of fostering strong group relationships in educational settings and cultivating individuals’ sense of responsibility toward peers and communities. This may mitigate cyberbullying and encourage proactive resistance against such behavior.