Neural correlates of metamemory: a comparison of feeling-of-knowing and retrospective confidence judgments

Abstract

Metamemory refers to knowledge and monitoring of one's own memory. Metamemory monitoring can be done prospectively with respect to subsequent memory retrieval or retrospectively with respect to previous memory retrieval. In this study, we used fMRI to compare neural activity during prospective feeling-of-knowing and retrospective confidence tasks in order to examine common and distinct mechanisms supporting multiple forms of metamemory monitoring. Both metamemory tasks, compared to non-metamemory tasks, were associated with greater activity in medial prefrontal, medial parietal, and lateral parietal regions, which have previously been implicated in internally directed cognition. Furthermore, compared to non-metamemory tasks, metamemory tasks were associated with less activity in occipital regions, and in lateral inferior frontal and dorsal medial prefrontal regions, which have previously shown involvement in visual processing and stimulus-oriented attention, respectively. Thus, neural activity related to metamemory is characterized by both a shift toward internally directed cognition and away from externally directed cognition. Several regions demonstrated differences in neural activity between feeling-of-knowing and confidence tasks, including fusiform, medial temporal lobe, and medial parietal regions; furthermore, these regions also showed interaction effects between task and the subjective metamemory rating, suggesting that they are sensitive to the information monitored in each particular task. These findings demonstrate both common and distinct neural mechanisms supporting metamemory processes and also serve to elucidate the functional roles of previously characterized brain networks.

Fig. 1

At study (not-scanned), subjects viewed novel faces three times in a face encoding task and face-name pairs once in a face-name encoding task. At test (scanned), subjects performed Feeling-of-Knowing (FOK), Recognition (REC), Confidence (CONF) and Attractiveness (A) tasks (right). Attractiveness ratings were given either pre-recognition (PreA) or post-recognition (PostA). The tasks were presented in 3 different randomized orders: FOK-REC-CONF, FOK-REC-PostA, FOK-PreA-REC in an event-related design.

Fig. 2

Calibration curves depicting the proportion of face-name pairs correctly recognized in each rating category (Know/Knew, High, and Low) for both feeling-of-knowing (FOK) and confidence judgments (CONF).

Fig. 3

Whole-brain analyses comparing metamemory tasks (feeling-of-knowing and confidence judgments) to non-metamemory tasks (recognition and attractiveness ratings).

Fig. 4

Regions that showed differences in activity for feeling-of-knowing (FOK) and confidence judgments (CONF). Regions for FOK > CONF are shown on the right hemisphere only, but a similar pattern was observed on the left. There was greater activity during FOK than CONF medial parietal (Med. Par; BA 31/7), medial temporal lobe (MTL), fusiform (Fus; BA 37), and superior temporal gyrus (STG; BA 21). An anterior left inferior prefrontal regions (aLIPC; BA 47) was significant for CONF>FOK. Graphs depict percent signal change in these regions sorted by task (FOK or CONF), level (High or Low FOK or CONF) and recognition accuracy (hits or misses) with significant effects of tasks and task interactions (also see Table 4.3). Post-hoc analyses with 2 × 2× 2 Task x Level x Accuracy ANOVAs on percent signal change data indicated that FOK>CONF regions showed consistent task differences across behavioral response whereas CONF>FOK regions may have been driven by specific behavioral effects.

Fig. 5

Regions that modulated based on High or Low Feeling-of-Knowing (FOK), regardless of accuracy. Map-wise comparisons revealed greater activity during High FOK compared to Low FOK in left anterior dorsolateral prefrontal (BA 10/9; top) and right anterior ventrolateral prefrontal (BA 45; bottom) regions. Repeated measures ANOVAs on percent signal change in these regions showed task x level interactions and indicated that these regions modulated based on level of FOK expressed but not level of confidence (CONF) expressed.