Growth mindset intervention and academic engagement: the mediating role of l2 motivational self system among non-English majors

Non-English major students in Chinese higher education frequently exhibit insufficient motivation and declining academic engagement in compulsory English courses. Although growth mindset theory and the L2 Motivational Self System (L2MSS) have each been associated with language learning outcomes, intervention research integrating these traditions remains scarce, and the psychological pathways linking implicit ability beliefs to engagement behaviors are not well understood. Drawing on possible selves theory and self-discrepancy theory as a unifying framework, this study examined the longitudinal effects of a growth mindset intervention on non-English major students’ L2MSS and academic engagement, and tested whether the L2MSS mediates the intervention–engagement relationship. A quasi-experimental design with cluster randomization at the class level assigned 120 first-year undergraduates to an experimental group ( n = 60) and a control group ( n = 60). The experimental group received a 12-week growth mindset intervention integrated into regular English instruction, comprising four modules: cognitive restructuring, attribution training, growth-oriented feedback, and metacognitive strategy instruction. Data were collected at three time points across one semester (T1 baseline, T2 mid-intervention, T3 post-intervention), measuring growth mindset, L2MSS components (ideal L2 self, ought-to L2 self, and L2 learning experience), and academic engagement dimensions (behavioral, emotional, and cognitive). Repeated measures ANOVA examined intervention effects, and bias-corrected bootstrap mediation analyses with a temporally ordered model (T1 → T2 → T3) tested mediating pathways. Repeated measures ANOVA revealed significant Group × Time interactions for all three L2MSS components and all three engagement dimensions, indicating that the intervention was associated with gains in motivational selves and engagement. The largest effects were observed for ideal L2 self and L2 learning experience. Bootstrap mediation analyses suggested that the L2MSS, particularly the ideal L2 self, may have functioned as a mediating mechanism, accounting for approximately 78.5% of the total intervention effect on engagement (total indirect effect β = 0.665, 95% CI [0.521, 0.821]), with the ideal L2 self alone contributing about 51%. Findings indicate that a classroom-integrated growth mindset intervention can meaningfully reshape non-English major students’ L2 motivational selves and academic engagement, with effects transmitted primarily through enhanced ideal L2 self construction. These results extend theoretical understanding of how implicit beliefs, domain-specific motivational constructs, and learning behaviors connect, and they offer practical guidance for educators seeking to address motivation and engagement challenges in foreign language classrooms. Causal inferences should be tempered by the quasi-experimental design and absence of delayed follow-up assessment.