biostudies-literatureLampe JFSwiss National Science Foundatione0224282https://www.ebi.ac.uk/biostudies/studies/S-EPMC6812795biostudies-literatureUnknown14(10)Social play is associated with the experience of positive emotions in higher vertebrates and may be used as a measure of animal welfare. Altering motivation to play (e.g., through short-term social isolation) can temporarily affect play levels between familiar individuals, a process which may involve emotional contagion. This study investigated how forming groups based on known differences in the personality trait "playfulness" (i.e., the longer-term propensity of an individual to actively play from adolescence to early adulthood) affects social play. Seventy-six adolescent male Lister Hooded rats underwent a Play-in-Pairs test assessing their playfulness, ranked as high (H), intermediate (I) or low (L). At seven weeks of age, rats were resorted into homogenous groups of similar (LLL, III,PloS onePlay like me: Similarity in playfulness promotes social play.PMC681279531003A_144088Lampe JFWurbel HMelotti LBurman ORuchti SfalsePlay like me: Similarity in playfulness promotes social play.Social play is associated with the experience of positive emotions in higher vertebrates and may be used as a measure of animal welfare. Altering motivation to play (e.g., through short-term social isolation) can temporarily affect play levels between familiar individuals, a process which may involve emotional contagion. This study investigated how forming groups based on known differences in the personality trait "playfulness" (i.e., the longer-term propensity of an individual to actively play from adolescence to early adulthood) affects social play. Seventy-six adolescent male Lister Hooded rats underwent a Play-in-Pairs test assessing their playfulness, ranked as high (H), intermediate (I) or low (L). At seven weeks of age, rats were resorted into homogenous groups of similar (LLL, III,2019-01-01T00:00:00Z20192025-04-19T04:03:43.439Z2019-11-09T08:01:17ZS-EPMC68127953164825010.1371/journal.pone.0224282