Neural dynamics of metacognitive monitoring: a dual-stage perspective on judgments of learning

It is well established that monitoring one's memory performance involves engaging in metacognitive monitoring and activating the frontal cortex. Judgments of Learning (JOLs) are individuals' assessments of the likelihood of remembering a specific item on a future test, usually occurring after learning and before testing. An ongoing debate exists regarding whether participants' metacognitive monitoring is based on a single process or two distinct processes when making JOLs. In this study, we investigated the electrophysiological correlates of JOLs induced by an episodic memory task in 38 adult participants. Participants completed a word pairs memory task and rated their memory performance after remembered whole items. We observed that participants with high judgments of learning had faster reaction times compared to those with low judgments of learning. The electrophysiological results revealed that low judgments of learning were associated with a more negative frontal-central N400-600 amplitude, while high judgments of learning were associated with a larger frontal-parietal slow wave amplitude. Furthermore, low judgments of learning exhibited greater theta band event-related synchronization (theta-ERS) and beta band event-related desynchronization (beta-ERD) during the metacognitive monitoring phase compared to high judgments of learning. Brain-behavior correlations also indicated a relationship between the 600-1000 component and behavioral performance, highlighting differential effects between high and low JOLs when making metacognitive monitoring ratings. These findings extend previous research and suggest that the formation of JOL ratings involves two distinct stages: the first stage involves obtaining retrieval fluency cues (frontal-central N400-600 amplitude), while the second stage involves utilizing these cues for metacognitive monitoring (frontal-parietal slow wave amplitude). Varying item familiarity and degrees of retrieval familiarity contribute to differences in JOL ratings. In summary, this study provides compelling evidence for a two-stage process in metacognitive monitoring ratings from both neurophysiological and brain-behavior correlation perspectives.