The dorsal anterior cingulate cortex (dACC) is thought to be essential for normal adaptation of one's behavior to difficult decisions, errors, and reinforcement. Here we examine single neurons from the human dACC in the context of a statistical model, including a cognitive state that varies with changes in cognitive interference induced by a Stroop-like task. We then include this cognitive state in point process models of single unit activity and subject reaction time. These results suggest that consideration of a latent cognitive state can explain additional variance in neural and behavioral dynamics.