Roles of the MPFC and insula in impression management under social observation.

People often engage in impression management by presenting themselves and others as socially desirable. However, specific behavioral manifestations and underlying neural mechanisms of impression management remain unknown. In this study, we investigated the neural mechanism of impression management during self- and friend-evaluation. Only participants assigned to the observation (OBS) group, not the control (CON) group, were informed that their responses would be monitored. They answered how well positive and negative trait adjectives described themselves or their friends. The behavioral results showed that the OBS group was more likely to reject negative traits for self-evaluation and to accept positive traits for friend-evaluation. An independent study revealed that demoting negative traits for oneself and promoting positive traits for a friend helps manage one's impression. In parallel with the behavioral results, in the OBS vs the CON group, the rostromedial prefrontal cortex (rmPFC) and anterior insula (AI) activity showed a greater increase as the negativity of negatively valenced adjectives increased during self-evaluation and also showed a greater increase as the positivity of positively valenced adjectives increased during friend-evaluation. The present study suggests that rmPFC and AI are critically involved in impression management, promoting socially desirable target evaluations under social observation.