Will rumination necessarily amplify the impact of cyber-ostracism on college students' cyber-aggression? Evidence from longitudinal data.

Cyber-ostracism, a prevalent form of online social exclusion among college students, has been increasingly associated with aggressive behaviors in digital environments. Grounded in the General Aggression Model (GAM) and the Temporal Need-Threat Model (TNTM), this study examines the longitudinal mechanisms through which cyber-ostracism promotes cyber-aggression, emphasizing the mediating role of negative rumination and the moderating effect of positive rumination. A two-wave longitudinal design spanning six months was employed, involving 1166 college students (51.63 % female; M = 19.79, SD = 1.13) from six universities in southeastern China. Participants completed standardized measures assessing cyber-ostracism, rumination (both positive and negative), and cyber-aggression. Structural equation modeling revealed that: (1) cyber-ostracism significantly predicted cyber-aggression; (2) this relationship was partially mediated by negative rumination; and (3) positive rumination moderated the pathway from negative rumination to cyber-aggression, attenuating the association as its level increased. These findings suggest that negative rumination functions as a cognitive-emotional amplifier of the effects of social exclusion, whereas positive rumination may serve as a protective factor. This study advances the theoretical understanding of aggression in digital contexts by elucidating the dynamic interplay between social exclusion and self-regulatory processes, offering empirical insights for psychological interventions targeting maladaptive cognition among youth.