Neural representation of decision confidence.

Decision confidence is a person's strength of belief about the optimization or correctness of a prediction, judgment, or choice. A broad range of behavioral data focus on calibration studies, however, little is known about the mechanisms underlying decision confidence. We used functional magnetic resonance imaging to investigate the neural activity while subjects made optional decisions by estimating the degree of confidence in perception task. Behaviorally, there was a significant increase in the accuracy of optional decisions compared with forced decisions, which proved the effectiveness of inducing the confidence estimation. Confidence process was mainly associated with activity in the superior parietal lobule, anterior cingulate cortex and superior frontal cortex. The behavioral waiving responses were predicted by a measure of neural decision confidence in the left superior parietal lobule. The activation in this region was correlated positively with the waiving rate, indicating the involvement of the representation of the decision confidence. These results suggested that the process of decision confidence might have evolved a more abstract and complicated network and involved in lots of cognitive functions. More importantly, the representation of decision confidence might be associated with the left superior parietal lobule.