Beyond Elaboration: How Metacognition, Co-regulation, and Social Presence Converge to Drive Engagement in Problem-Based Learning

Problem‑based learning (PBL) is intended to foster collaborative knowledge construction, yet the moment‑to‑moment interplay of metacognition, co‑regulation, and socio‑emotional interaction in PBL tutorials remains underexplored. This mixed‑methods study examined discourse processes in four first‑year medical PBL groups discussing an obstructive sleep apnoea case. Ninety‑minute tutorials were video‑recorded, transcribed, segmented into meaning units, and coded for metacognitive activity, co‑regulation, social‑emotional interaction, and tutor moves. Quantitative analyses included code frequencies, lag sequential analysis of discourse transitions, and Epistemic Network Analysis to model co‑occurrence patterns. Across 649 coded segments (544 student, 105 tutor), elaboration was the dominant metacognitive activity, with orientation, evaluation, and planning also frequent. Co‑regulatory moves were mainly activating and confirming peers, while slowing and change‑oriented regulation were rare. Interactive social presence was the prevalent socio‑emotional form; negative socio‑emotional moves were not observed. The epistemic network revealed a densely connected core linking elaboration, planning, orientation, evaluation, activating, confirming, and interactive social presence, indicating that reasoning, co‑regulation, and social engagement were tightly integrated. Lag sequential analysis showed that elaborative and tutor‑initiated prompts often triggered extended metacognitive sequences, whereas tutor clarifications were uniquely associated with metacognitive moves that also expressed social support. These findings portray PBL as a socio‑cognitively integrated activity and highlight elaboration‑centred discourse, supportive co‑regulation, and facilitative tutor questioning as key levers for fostering productive, psychologically safe collaboration in medical education.