Stranger-directed consolation-like behavior in mice in a test of social decision making

In the past decade, investigations into the neurobiology of empathy have been propelled by evidence that rodents are capable of more complex and nuanced social behaviors than previously believed. Several teams have reported that rodents will direct allogrooming and other consolation-like behaviors towards distressed conspecifics, including in situations in which consolation-like behavior was not the explicit focus of a given study. As a case in point, we unexpectedly found in a test of decision making incentivized by social experience that mice display consolation-like allogrooming towards distressed strangers. This observation was somewhat surprising because consolation-like behavior in rodents is often believed to be reserved for familiar conspecifics. Here in this brief report, we reveal that the allogrooming and close social proximity with a distressed stranger that we previously reported was accompanied by elevated sniffing and autogrooming in close proximity to the conspecific - a social contagion-like behavior. Also, these behaviors were not obviously attributable to general hyper-activity. We then describe the conditions in which this constellation of stranger-directed consolation-related behavior was observed, should this information support new research concerning stranger-directed consolation-like behavior.