Our subjective confidence about particular events is related to but independent from the objective certainty of the stimuli we encounter. Surprisingly, previous investigations of the neurophysiological correlates of confidence and uncertainty have largely been carried out separately. After systematically reviewing the blood oxygenation-level dependent functional magnetic resonance imaging (BOLD fMRI) literature, and splitting studies on the basis of their task requirements, a voxel-based meta-analysis was performed to identify: (i) those regions which are replicably modulated by the uncertainty of environmental conditions; (ii) those regions whose activity is robustly affected by our subjective confidence; and (iii) those regions differentially activated at these contrasting times. In further meta-analyses the consistency of activation between these judgement types was assessed. Increased activation was consistently observed in the salience (anterior cingulate cortex and insula) and central executive network (dorsolateral prefrontal and posterior parietal cortices) in conditions of increased uncertainty; by contrast, default mode network (midline cortical and medial temporal lobe) regions robustly exhibited a positive relationship with subjective confidence. Regions including right parahippocampal gyrus were positively modulated by magnitude across both certainty and confidence judgements. This region was also shown to be more significantly modulated by confidence magnitude as compared with degree of environmental certainty. The functional and methodological implications of these findings are discussed with a view to improving future investigation of the neural basis of metacognitive judgement.
Brain and Cognition, 2014, Vol 85, Issue 1, p. 191-200