Personalized GenAI coaching and self-regulation in L2 writing across a nine-week active-control study

Abstract

Introduction Personalized rationale is an explanation of why a metacognitive strategy is relevant to a learner’s current writing. This study compared a personalized GenAI coaching package with template-based adaptive metacognitive prompting (AMP) in a nine-week randomized study of Chinese EFL undergraduates. Methods Ninety-two participants completed pretest, posttest, and three-week delayed posttest assessments. Both conditions used the same Doubao LLM, interface, and trigger infrastructure. The AMP-Agent condition combined an essay-specific observation, personalized rationale, and an open-ended question; the AMP condition used template prompts. Results Analyses of questionnaire item responses found Group × Time interactions for self-regulated learning (SRL; p = 0.019) and GenAI dependency (p = 0.010), which also survived a retrospective Holm sensitivity correction across the three total outcomes. The SRL total contrasts at posttest and delayed posttest did not survive Bonferroni correction across time points. Self-reported GenAI dependency questionnaire scores were lower in the AMP-Agent group at both later assessments after this correction. Evidence for different writing-score trajectories was insufficient (interaction p = 0.101). None of five highlighted behavioral transitions survived correction across 20 transition comparisons. Discussion The findings support a difference in self-reported regulation and dependency trajectories between the two prompting packages, while leaving the contribution of rationale alone, sustained writing benefits, and psychological mechanisms unresolved.