Articles

High-quality collaborative discourse is essential for deep learning in Problem-Based Learning (PBL). However, novice facilitators frequently struggle with topic drift, which occurs when discussions deviate from core learning objectives. Grounded in Cognitive Load Theory and instructional scaffolding, this paper analyzes the cognitive mechanisms behind topic drift in PBL. It identifies three typical deviation patterns: "Premature Resolution" (bypassing mechanistic deduction), "Detail Fixation" (over-engagement with peripheral details), and "Social Avoidance" (stemming from dysfunctional group dynamics). To address these patterns, this paper presents a literature-based facilitation guide offering specific intervention strategies and discursive prompts. These include mechanistic backtracking, metacognitive monitoring, and cognitive visualization. The study argues that effective pedagogical intervention relies on the strategic timing of facilitation rather than the immediate correction of factual errors. Ultimately, built on a foundation of relational trust, this process requires educators to shift their role from "epistemic authorities" to "cognitive coaches."