The storm and stress (or calm) of early adolescent self-concepts: within- and between-subjects variability.

This study uses intraindividual variability and change methods to test theoretical accounts of self-concept and its change across time and context and to test the developmental implications of this variability. The 5-year longitudinal study of 541 youths in a rural Pennsylvania community from 3rd through 7th grade included twice-yearly assessments of self-concept (academic and social), corresponding external evaluations of competence (e.g., teacher-rated academic skills, peer-nominated "likeability"), and multiple measures of youths' overall adjustment. Multiphase growth models replicate previous research, suggesting significant decline in academic self-concept during middle school but modest growth in social self-concept from 3rd through 7th grade. Next, a new contribution is made to the literature by quantifying the amount of within-subject variability (i.e., "lability") around these linear self-concept trajectories as a between-subjects characteristic. Self-concept lability was found to associate with a general profile of poorer competence and adjustment and to predict poorer academic and social competence at the end of 7th grade above and beyond level of self-concept. Finally, there was substantial evidence that wave-to-wave changes in youths' self-concepts correspond to teacher and peer evaluations of youths' competence, that attention to peer feedback may be particularly strong during middle school, and that these relations may be moderated by between-subjects indicators of youths' general adjustment. Overall, findings highlight the utility of methods sensitive to within-subject variation for clarifying the dynamics of youths' self-system development.