Human dorsomedial prefrontal cortex delineates the self and other against the tendency to form interdependent social representations

Summary To navigate social environments, people must simultaneously hold representations about their own and others’ abilities. During self-other mergence, people estimate others’ abilities not only on the basis of the others’ past performance, but the estimates are also influenced by their own performance. For example, if we perform well, we overestimate the abilities of those with whom we are co-operating and underestimate competitors. Self-other mergence is associated with specific activity patterns in the dorsomedial prefrontal cortex (dmPFC). Using a combination of non-invasive brain stimulation, functional magnetic resonance imaging, and computational modeling, we show that dmPFC neurostimulation silences these neural signatures of self-other mergence in relation to estimation of others’ abilities. In consequence, self-other mergence behavior increases, and our assessments of our own performance are projected increasingly onto other people. This suggests an inherent tendency to form interdependent social representations and a causal role of the dmPFC in separating self and other representations.
Highlights • During self-other mergence (SOM), people confuse one’s own with another’s performance • Brain stimulation over dorsomedial prefrontal cortex (dmPFC) alters neural SOM • Brain stimulation over dmPFC simultaneously alters behavioral SOM • This suggests a causal role of dmPFC in separating self and other representations
Wittmann et al. find that, after disrupting activity in the dorsomedial prefrontal cortex, humans merge performance estimates concerning other people with performance estimates about themselves. This suggests that representations of self and others are inherently interlinked and that intact dmPFC activity is needed for separating the two.