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Wednesday, July 14, 2021

Popularity is linked to neural coordination: Neural evidence for an Anna Karenina principle in social networks

Baek, E. C.,  et al. (2021)


People differ in how they attend to, interpret, and respond to their surroundings. Convergent processing of the world may be one factor that contributes to social connections between individuals. We used neuroimaging and network analysis to investigate whether the most central individuals in their communities (as measured by in-degree centrality, a notion of popularity) process the world in a particularly normative way. More central individuals had exceptionally similar neural responses to their peers and especially to each other in brain regions associated with high-level interpretations and social cognition (e.g., in the default-mode network), whereas less-central individuals exhibited more idiosyncratic responses. Self-reported enjoyment of and interest in stimuli followed a similar pattern, but accounting for these data did not change our main results. These findings suggest an “Anna Karenina principle” in social networks: Highly-central individuals process the world in exceptionally similar ways, whereas less-central individuals process the world in idiosyncratic ways.


What factors distinguish highly-central individuals in social networks? Our results are consistent with the notion that popular individuals (who are central in their social networks) process the world around them in normative ways, whereas unpopular individuals process the world around them idiosyncratically. Popular individuals exhibited greater mean neural similarity with their peers than unpopular individuals in several regions of the brain, including ones in which similar neural responding has been associated with shared higher-level interpretations of events and social cognition (e.g., regions of the default mode network) while viewing dynamic, naturalistic stimuli. Our results indicate that the relationship between popularity and neural similarity follows anAnna Karenina principle. Specifically, we observed that popular individuals were very similar to each other in their neural responses, whereas unpopular individuals were dissimilar both to each other and to their peers’ normative way of processing the world.  Our findings suggest that highly-central people process and respond to the world around them in a manner that allows them to relate to and connect with many of their peers and that less-central people exhibit idiosyncrasies that may result in greater difficulty in relating to others.