Munetada Harada

The purpose of this study was to develop a scale to measure the self-image instability of early adolescents. The subjects were 937 students (272 fifth and sixth graders and 665 junior high school students) who responded to a self-report questionnaire twice, one month apart. Factor analysis revealed that the self-image instability scale includes three subscales: positive changes, negative changes, and neutral instabilities. The scale demonstrated good correlations with test–retest and existing scales. Negative self-image changes and neutral instabilities had positive correlation with stress responses, while positive changes had small negative correlations with stress responses.

Although previous research indicates that victimization and self-image instability relate to bullying, the causal relationships between these variables are unclear. The primary purpose of this study was to examine how self-image instability and victimization relate to bullying. Participants were 1,362 children (420 elementary school children and 942 junior high school children), who answered a self-report questionnaire three times in one year. The questionnaire measured self-image instability, bullying, and victimization. In the first questionnaire, participants were asked to report the degree of experienced bullying and victimization from April until the present. The second and third questionnaires recorded bullying and victimization between the previous self-report and the present. Longitudinal data analyses using a cross-lagged model indicated self-image instability predicted victimization, and victimization marginally predicted bullying for only junior high school children.