Neuroimaging Investigations of Social Status and Social Hierarchies

Social hierarchies are omnipresent in the lives of many species. The ability to successfully navigate complex social environments with consideration of the relative rank of conspecifics is an essential skill not only for humans, but also for numerous other social beings. From maintaining rank and reducing conflict, to communication and reproduction, organisms of varying complexity rely on social hierarchies to support social interactions. Hierarchical social structures can provide order and clarify the roles of individual group members, thus facilitating social coordination. Furthermore, in some instances, status-based hierarchies can incentivize those lower in relative rank to progress and achieve higher standing among their peers, thus providing motivation to perform a variety of behaviors. Social hierarchies have been identified across a broad range of organisms, from simpler model systems such as insects, to nonhuman and human primates. For example, reliance on status cues to organize important social behavior is identified in ants1 and other insects, such as bees, who infer higher ranking in the social hierarchy based on physical body size.2 Many species of fish are also known to rely on social hierarchies. For example, in Cichlasoma dimerus males (South American cichlid fish known to have stable and linear hierarchies), a greater social position within the hierarchy has been linked to lower relative stress levels and increased reproductive success.3 O U T L I N E