In self decisions, the perigenual ACC represented the performance of oneself (parametric regressor indicating trial-wise performance scores for self), whereas a more dorsomedial region represented partner performance in partner decisions, replicating previous results on self/other coding in the prefrontal cortex (peak MNI coordinates of the effects are in brackets). Both signals were positively signed and extended bilaterally. Sample sizes: n = 56 for the social fMRI experiment (study 1); n = 795 for the behavioural experiment (study 2); error bars show s.e.m.; two-sided paired t -tests were used in c and d ; all MRI results cluster are family-wise error (FWE) corrected at Z > 3.1, P = 0.05; * P < 0.05, *** P < 0.001.
