Metacognition and Confidence in Value-Based Choice

Basic psychophysics tells us that decisions are rarely perfect: even with identical stimuli choice accuracy fluctuates and errors are often made. Metacognition allows appraisal of this uncertainty and correction of errors. For more complex value-based choices, however, metacognitive processes are poorly understood. In particular, how subjective confidence and valuation of choice options interact at the level of brain and behaviour is unknown. In this chapter, we summarise and discuss the results of a study designed to investigate this relationship. Subjects were asked to choose between pairs of snack items and subsequently provide a confidence rating in their choice. As predicted by a computational model of the decision process, confidence reflected the evolution of a decision variable over time, explaining the observed relation between confidence, value, accuracy and reaction time (RT). Furthermore, fMRI signal in human ventromedial prefrontal cortex (vmPFC) reflected both value comparison and confidence in the value comparison process. In contrast, individuals’ metacognitive ability was predicted by a measure of functional connectivity between vmPFC and rostrolateral prefrontal cortex (rlPFC), a region that responded to changes in confidence but was not involved in representing the values used to guide choice. These results provide a novel link between noise in value comparison and metacognitive awareness of choice, extending the study of metacognition to value-based decision-making