School bullying occurs frequently in primary and secondary schools, which is a global problem and it often brings serious physical and mental harm to the victims. When school bullying occurs, there may be a large number of bystanders in addition to the bullies and victims. What actions bystanders take affects the progress of school bullying. Relevant studies indicate that social norms including how peers around them react (descriptive norms) and how important adults such as teachers and parents demand (injunctive norms) play important roles in bystanders' action-taking, but limited studies have considered individual differences. Therefore, this study used a person-centered approach to explore the co-existence patterns of social norms and bystanders' defending intention to further understand their relations. We surveyed 1,384 junior high school students in China by self-report questionnaires, and they were asked to assess their defending intention when witnessing school bullying events under different contexts of social norms. Through latent profiles analysis, five co-existing patterns were identified: no norms-no defending group (4.8%), parent norms-no defending group (3.6%), weak norms-low defending group (24.3%), teacher-peer norms-medium defending group (40.6%), teacher-peer norms-high defending group (26.7%). In four out of the five patterns, students' levels of defending intention were highly consistent with the levels of peer and teacher norms, but largely contradicted parent norms. This suggests that descriptive norms from peers and injunctive norms from teachers, other than those from parents are crucial for promoting bystanders' defending intention, which provides important enlightenment for school bullying prevention. These findings provide important enlightenment for the prevention and control of school bullying in the future.
Keywords: adolescent; bystanders; defending intention; school bullying; social norms.