RESUMEN
Background: The significant influence of family emotional expressiveness (FEE) on adolescents' face-to-face social interactions is well-established. However, there has been limited investigation into potential links between FEE and adolescents' online social behaviors, especially cyberbullying bystander behaviors, which are pivotal in cyberbullying incidents. This study aimed to assess the relative importance of different aspects of FEE (positive FEE vs. negative FEE vs. the Positive-to-Negative ratio) in predicting adolescents' cyberbullying bystander behaviors, and the mediating roles of affective and cognitive empathy in these relationships. Methods: A sample of 1,952 adolescents (Mage = 14.18, SD = 1.33) completed questionnaires, including the Family Emotional Expressiveness Questionnaire, Basic Empathy Scale, and Cyberbullying Bystander Behavior Scale. SPSS 26.0 and Mplus 8.3 were used for analysis. Results: (1) Positive FEE exhibited a positive association with protective behavior and a negative association with indifferent behavior. Conversely, negative FEE showed positive associations with reinforcing and indifferent behaviors. However, the Positive-to-Negative ratio did not exhibit significant associations with any of the three bystander behaviors. (2) Negative FEE emerged as relatively more significant than both positive FEE and the Positive-to-Negative ratio in predicting reinforcing and indifferent behaviors. (3) Affective empathy mediated the relationship between positive FEE and reinforcing behavior, while cognitive empathy mediated the relationship between positive FEE and protective and indifferent behaviors. Moreover, cognitive empathy exerted a more influential role than affective empathy in this mediation process. Conclusion: Various aspects of FEE demonstrated distinct relationships with three cyberbullying bystander behaviors, with affective and cognitive empathy playing an important mediating role in the association. This finding holds substantial implications for the development of cyberbullying prevention strategies. Such strategies could target the reduction of negative emotional expression within adolescent families and the cultivation of both cognitive and affective empathy.