This research examines mass fighting instances among high school students in Jakarta, which has been existing since 1970s up to now. Mass fighting instances were studied as collective behavior phenomena. Thus its unit of analysis are collectivities, i.e. groups of high school students who are involved in the incidence of mass
fighting. The analysis model developed in this research was derived from Smelser's as well as Tilly's theories on collective behavior. As a consequence the analysis of mass fighting has four components: i.e. conflict tradition, ability for mobilization, precipitated factors, and opportunity which should be found simultaneously in every incidence.
Research method used was a multiple-case study as based for the reconstruction of the reality of mass fighting. To conduct this method, high school student collectivities were divided into three categories, i.e. fighting group of high school with conflict tradition, non-fighting group of a high school with conflict tradition, and non-fighting
group of high school without conflict tradition. Each group were repsresented by 50 male students, who were selected incidentally.
Research results suggest that the differences found between fighting group with non-fighting group rooted in whether or not the components of mass fighting were existed. Such differences lead to the differences in their subjectivity in constructing reality. Since individual of students from different group (of this research) reveal
social-economics differences, as a consequence their life experience, opportunity, and expectation were also different. They will comprehend and react differently when they face similar situation problems existed in every incidence of mass fighting.
