Winokur, E. J., Song, C., Leija, E. S., Chen, J., Kross, S., Shamam, D., Aguilar-Rivera, M., Quinn, L. K., Rossano, F., & Chiba, A. A. (2023). Reciprocity in dyads and triads: Female rats alter their prosocial behavior according to the social context. Animal Behavior and Cognition, 10(3), 169-210. https://doi.org/10.26451/abc.10.03.01.2023

Recognizing and appropriately responding to others' helpful actions are critical components of social cognition and reciprocity. This ability has been well-documented in various species where animals differentiate between experimenters who are “unwilling” versus “unable” to provide help, but it is unclear if this ability extends to rats. The present studies investigate the prosocial decision-making behavior of female rats in response to the prior actions of another rat in both triadic and dyadic social contexts. In Experiment One, an "actor" rat repeatedly pressed a lever to open a restrainer door, enabling a trapped conspecific to access food. Consistent with reciprocity, when the roles were reversed, the previously trapped conspecific helped the actor. In Experiments Two and Three, the actor rat's ability to open the door was manipulated, with some trials where the door was blocked and the actor was unable to open it and some trials where the actor was able to, but rarely opened the door. In the triadic context, the previously trapped rat then had the opportunity to help the actor, a neutral control, both, or neither (Experiment Two). In the dyadic context, the previously trapped rat could then help the actor (Experiment Three). Reciprocity was not observed in the triadic context. However, unexpectedly, relative to a neutral control conspecific, rats showed a stronger preference for the less helpful actor compared to the helpful or unable actor. In contrast, in the dyadic context, rats did show reciprocity and displayed a higher propensity to help the helpful or unable actor compared to the less helpful actor. These findings shed light on rats' complex social behavior and highlight the context-dependent nature of their helping behavior. 

Rat, Reciprocity, Helping behavior, Social triads, Social decision making, Prosociality