Associations between childhood emotional maltreatment and negative bystander behavior in cyberbullying among adolescents: a three-wave longitudinal study

Negative bystander behaviors significantly shape the trajectory of cyberbullying incidents. Previous research has established a link between childhood emotional maltreatment and negative bystander behavior in cyberbullying. However, little is known about the longitudinal mechanisms underlying this relationship. To address this gap, the current study investigated the mediating role of callous‑unemotional traits and the moderating role of perceived social support in the longitudinal association between childhood emotional maltreatment and negative bystander behavior in cyberbullying. A total of 1531 Chinese adolescents (49.8% female) with an average age of 16.12 years ( SD = 0.34) participated in a three-wave longitudinal study with 6-month intervals. Validated self-report measures were used to assess childhood emotional maltreatment, callous‑unemotional traits, perceived social support, and negative bystander behavior in cyberbullying. A moderated mediation model was tested using path analysis with bootstrapping (5000 resamples), after confirming the measurement model via confirmatory factor analysis. The results revealed that childhood emotional maltreatment was positively associated with negative bystander behavior in cyberbullying 12 months later, and this association was mediated by callous‑unemotional traits. Perceived social support buffered the association between childhood emotional maltreatment and callous‑unemotional traits and mitigated the link between callous‑unemotional traits and negative bystander behavior. Further findings revealed that the indirect pathway of callous‑unemotional traits was more pronounced when levels of perceived social support were low, and higher levels of perceived social support could disrupt the mediating pathway of callous‑unemotional traits between childhood emotional maltreatment and negative bystander behavior in cyberbullying. This study enhances understanding of the longitudinal mechanisms linking childhood emotional maltreatment to negative bystander behavior in cyberbullying through callous‑unemotional traits. The findings highlight the importance of promoting perceived social support as a buffer that can disrupt this mediating pathway, providing empirical evidence for interventions aimed at reducing negative bystander behavior in cyberbullying among adolescents.