We investigated whether the activation of self-knowledge reduces conflict during occupational choice, which can elicit many correct answers. Conflict was measured via event-related brain potentials (ERPs). Results of this study showed that activation of self-knowledge reduces conflict during occupational choice. Our results suggest that, in a situation in which two or more possible correct answers exist, people use self-knowledge as a benchmark to reduce conflict by biasing either choice of behavior.

The 2001 conflict monitoring hypothesis of Botvinick and colleagues posits that the amount of conflict raised by incongruent stimuli in a flanker task affects subsequent cognitive control, such as response inhibition. The present experiment yielded empirical evidence of the quantitative relation between conflict and response inhibition. Participants judged the direction of a target arrow flanked by distractor arrows presented above and below the target. The amount of conflict was manipulated by varying the distance between the target and the directional distractors. Analysis showed that response times were longer for incongruent trials than for congruent trials, and response times on incongruent trials were longer for the small distance than for the large distance conditions. In addition, the response times in congruent trials became longer as the amount of conflict in the preceding trial increased. These results are consistent with Botvinick, et al.'s hypothesis that the conflict-detection mechanism determines the amount of response inhibition depending on the amount of conflict. Responses on incongruent trials were faster and more accurate when the preceding trial was incongruent than when it was congruent, and the size of this response facilitation was not influenced by the amount of conflict. These results suggest that the conflict detection mechanism modulates the subsequent behaviors by two forms of control which are differently affected by the amount of conflict.

Medial prefrontal cortex (MPFC) activation has been observed in studies of many types related to emotion regulation, self and familiar other-knowledge, mentalizing, morality, reward, and uncertainty. Furthermore, the anterior cingulate cortex (ACC) and the lateral prefrontal cortex (LPFC), which have reciprocal connections with MPFC, are considered necessary for cognitive regulation. Based on these findings, Nakao, Takezawa, and Miyatani (2006) proposed an integrative explanation for MPFC function: MPFC has a function of representing a benchmark that reduces conflict among many possible answers by biasing either choice of behavior. In this article, we review studies related to MPFC function and the benchmark hypothesis with recent new findings. Additionally, we discuss emotion regulation, which was not described in Nakao et al. (2006), in relation to the benchmark hypothesis.

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For this study, functional magnetic resonance imaging was used to examine whether medial prefrontal cortex (MPFC) activity during self-knowledge reference reflects the uniqueness of self-knowledge. Experiment 1 investigated neural activity during self-knowledge reference ("Does the word describe you?") and self-monitoring ("Does the word make you feel pleasant?"). The results showed that self-knowledge reference and self-monitoring activate common neural substrates within the MPFC. Experiment 2 compared neural activity produced by self-knowledge reference, other-knowledge (acquaintance-knowledge) reference ("Does this word describe the person?"), and evaluation ("Is this word socially desirable?"). Results showed no increase in MPFC activity during self-knowledge reference relative to other-knowledge reference. Furthermore, self-knowledge reference and other-knowledge reference share common neural substrates within the MPFC. The results described indicate that it is unlikely that MPFC activity during self-knowledge reference reflects the uniqueness of self-knowledge. The feature, as reflected in MPFC activity, is discussed.