Brain systems specialized for knowing our place in the pecking order

From Kumaran et al.:

Highlights

•Social hierarchy learning is accounted for by a Bayesian inference scheme 

•Amygdala and hippocampus support domain-general social hierarchy learning 

•Medial prefrontal cortex selectively updates knowledge about one’s own hierarchy 

•Rank signals are generated by these neural structures in the absence of task demands

Summary

Knowledge about social hierarchies organizes human behavior, yet we understand little about the underlying computations. Here we show that a Bayesian inference scheme, which tracks the power of individuals, better captures behavioral and neural data compared with a reinforcement learning model inspired by rating systems used in games such as chess. We provide evidence that the medial prefrontal cortex (MPFC) selectively mediates the updating of knowledge about one’s own hierarchy, as opposed to that of another individual, a process that underpinned successful performance and involved functional interactions with the amygdala and hippocampus. In contrast, we observed domain-general coding of rank in the amygdala and hippocampus, even when the task did not require it. Our findings reveal the computations underlying a core aspect of social cognition and provide new evidence that self-relevant information may indeed be afforded a unique representational status in the brain.