Yue Li, Meihua Chen, Honggang Liu
The rapid expansion of interdisciplinary dual-degree programs in higher education poses unique challenges to students' identity construction, particularly in highly disparate disciplinary combinations like foreign languages and STEM. Existing research on learner identity in interdisciplinary contexts largely relies on cross-sectional data, failing to capture the dynamic evolution of identities. Accordingly, this longitudinal study draws on a multidimensional framework that conceptualizes learner identity across cognitive, emotional, and behavioral dimensions and employs Q methodology and semi-structured interviews to trace the identity trajectories of 19 undergraduates in an "English + Engineering" dual-degree program across three critical time points throughout their four-year undergraduate studies. Findings reveal that at just six months after entering the program, students displayed either pluralistic exploration or an early engineering preference. After two years of learning, surging academic pressure and curriculum fragmentation were closely associated with a convergence toward an engineering-anchored identity, with some students caught in a dilemma between the two majors. Approaching graduation, the majority constructed a firm engineering-dominant identity and came to English as a competitive edge, while a highly vulnerable minority fell into a deep identity crisis. The study concludes with practical implications, calling for genuinely integrated interdisciplinary curricula and targeted psychological and academic support to mitigate identity conflicts and foster healthy interdisciplinary self-development.