The relations between self and others are fluid and constantly changing but exert a profound influenceon our identity and emotional experiences. Indeed, human emotions are frequently and intensely social,and the people with whom we interact can alter our momentary mood. But does emotional “contagion”extend over prolonged periods of hours to days, and, if so, how does it propagate through interconnectedgroups? Answering this question is empirically challenging, because mood similarity in connectedindividuals can arise through multiple mechanisms (social influence, social selection, and shared externalcausation), making causal inferences hard to draw. We address this challenge using temporally high-resolution, longitudinal data from 2 independent, bounded social networks during periods of highcommunal activity and low external contact. Adolescent study participants (N 79) completed dailymood (n 4,724) and social interaction (n 1,775) ratings during residential performance tours ofclassical music lasting 5 to 7 days. Analyses using statistical network models show that in both networks,adolescent musicians became reciprocally more similar in mood to their interaction partners. Theobserved contagion effect was greater for negative than for positive mood. That is, although one maycatch a friend’s bad mood, the friend may feel less negative in the process. These results suggest amechanism for emotional buffering and the cost of social support. We found no evidence for socialselection based on mood. Indeed, participants were remarkably tolerant of their peers’ mood fluctuationsand showed no evidence of altering their patterns of social interaction accordingly.
