Neural response during self-disclosure. In addition to robust activity in the MPFC, a whole-brain random-effects contrast comparing self > other trials reveals activity in bilateral NAcc (P < 0.05, corrected) in both (A) study 1a (peak MNI coordinates: −10, 6, −12) and (B) study 1b (peak MNI coordinates: −6, 6, −8; indicated by arrows). (C) A region of interest in bilateral NAcc was independently defined using the Monetary Incentive Delay task (MNI coordinates: 10, 6, −4; −8, 4, −6). (D) Analysis of parameter estimates in this independently defined region confirmed that bilateral NAcc showed significantly greater response during self than during other trials in both studies 1a and 1b. Error bars depict SE calculated for within-subject designs.

Monetary value of self-disclosure. (A) Representative data from one participant in study 2. The x axis represents the difference between the monetary values associated with the two options presented in each trial. Each dot indicates the percentage of times that the participant chose to answer a self question over a fact question (orange), a self question over an other question (red), or an other question over a fact question (blue) at each of the monetary differences between those two options. Negative values indicate that participants incurred a relative monetary loss for answering a self question. The PSE was calculated as the point at which a cumulative normal distribution function, fit to these responses, passes 50%. This point represents the relative monetary value associated with one question type over the other. (B) Across all participants in study 2, answering a question about the self was worth significantly more than answering both a question about another person or a question about a fact. There was no significant difference in the relative monetary value of an other and a fact question. (C) Data from one participant in study 4. This participant showed the most negative PSE for self shared trials (solid red), forgoing 1 cent for each opportunity to share information about the self. (D) Across all participants in study 4, answering questions about the self was worth significantly more than answering questions about another person, and sharing answers with a friend was worth significantly more than answering questions privately. Each factor—self and sharing—contributed independently to the monetary worth of self-disclosure.

Introspecting about the self and disclosing that information to others serve as independent sources of reward. Whole-brain random-effects contrasts comparing (A) self > other and (B) shared > private from study 3 reveal significant reward activity in bilateral NAcc (P < 0.05, corrected; indicated by arrows). (C) A region of interest in bilateral NAcc, defined using the Monetary Incentive Delay task in the same set of subjects. (D) Parameter estimates from this independently defined region are graphically depicted for all four trial types: self shared (solid red), self private (dashed red), other shared (solid blue), and other private (dashed blue). Analyses of these parameter estimates confirmed that bilateral NAcc showed responses consistent with two independent sources of reward from self-disclosure: introspection about the self and sharing with others. Error bars depict SE calculated for within-subject designs.