Why do people need political identity, and what effect does individual learning have on forming her identity preference? Relatively little research has tried to answer these two questions. We address this issue by analyzing the relationship between individual's life cycle and identity preference change. In a formal model of Bayesian updating, we establish that the aging process and external political changes both lead the individual to the acquisition of a new identity (Taiwanese). We test these hypotheses by analyzing the effects of age and education on weighting new information and previous identity choice. The results of this analysis accord with our image of identity politics in Taiwan: democratic evolution acts as a self-selection or learning process aggregating the possible paths of further political developments. In this way of analysis, static scheme-led explanation is replaced by political learning in an uncertain setting.