The dorsal anterior cingulate cortex (dACC) plays a critical role in cognitive control over different domains of tasks. The dACC activities uniformly represent task-generic intensities of control signals across different tasks. However, it remains unclear whether the dACC activities could also encode task identities of control signals across different tasks. If so, how the two types of control information are coherently organized in the dACC? Decision uncertainty is an internally-generated control signal by retrospective monitoring, namely, metacognition, even with no external feedback. We here investigated neural representations of decision uncertainty accompanying three decision-making tasks in the domains of perception, rule-based inference, and memory using trial-by-trial univariate and multivariate analyses on functional magnetic imaging data acquired on human male and female healthy subjects. Our results demonstrated that the dACC represented decision uncertainty commonly across the three decision-ma...