Abstract
Autonomy is increasingly understood as a relationally embedded process rather than a pursuit of independence, yet few longitudinal studies track how volition develops across cultural and developmental contexts. This study examined the dual trajectories of individuating autonomy and relating autonomy across adolescence and educational transitions. Participants were 777 Taiwanese adolescents (48.8% female; M = 15.22 years, SD = 1.56), including junior high (n = 371) and senior high (n = 406) cohorts, each followed across four waves to yield eight cohort-sequential waves. Latent growth and Bayesian autoregressive models were used to estimate developmental change and subgroup differences by gender and educational stage. Individuating autonomy was stable across adolescence, whereas relating autonomy followed a curvilinear course—declining and later recovering—most evident among girls and senior high students. Boys and junior high students reported higher initial levels on both autonomy forms. The combined cohort model indicated gradual declines and synchronous short-term fluctuations, highlighting intraindividual variability beyond linear trends. Findings suggest that autonomy in relationally interdependent societies develops through differentiated yet interconnected pathways, reflecting dynamic coordination between self-endorsed action and relational attunement. Results deepen the application of Self-Determination Theory by demonstrating that volition is both culturally grounded and universally relevant—enacted within, rather than apart from, enduring relationships.