Evaluating the play fighting of rats: A sociological perspective

Play fighting is a prominent social behavior in juvenile rats and is widely used to assess social motivation, affect, and neurobiological function. Traditional dyadic paradigms quantify how much play occurs and how it is expressed but provide limited insight into how rats select play partners.

We synthesize evidence from group-based paradigms that allow animals to choose among multiple partners and highlight analytical approaches-including social network analysis and machine-learning-based tracking-that enable quantification of partner selection and group dynamics.

Across studies, rats do not distribute play randomly but show apparent partner preferences influenced by familiarity, strain, sex, dominance, and group composition. These preferences reveal socially relevant effects of experimental manipulations that are often undetected by conventional measures. Substantial individual variation exists in both selectivity and attractiveness as play partners.

Compared to dyadic testing, group-based paradigms uncover a sociological dimension of play behavior, revealing effects that may be masked when animals are restricted to a single partner. Dyadic tests remain useful for assessing play microstructure but may underestimate changes in social decision-making.

Assessing not only how rats play, but with whom they choose to play, is essential for understanding the regulation of social play. Integrating group-based paradigms with emerging analytical tools provides a more comprehensive framework for studying the neurobiology of social behavior.