title: Detecting emotional contagion in massive social networks.
abstract: Happiness and other emotions spread between people in direct contact, but it is unclear whether massive online social networks also contribute to this spread. Here, we elaborate a novel method for measuring the contagion of emotional expression. With data from millions of Facebook users, we show that rainfall directly influences the emotional content of their status messages, and it also affects the status messages of friends in other cities who are not experiencing rainfall. For every one person affected directly, rainfall alters the emotional expression of about one to two other people, suggesting that online social networks may magnify the intensity of global emotional synchrony.
authors.affiliation: Electrical and Computer Engineering Department, University of California San Diego, San Diego, California, United States of America.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Coviello
authors.affiliation: Political Science Department, University of California San Diego, San Diego, California, United States of America.
authors.forename: Yunkyu
authors.initials: Y
authors.lastname: Sohn
authors.affiliation: Facebook Inc., Menlo Park, California, United States of America.
authors.forename: Adam D I
authors.initials: AD
authors.lastname: Kramer
authors.affiliation: Facebook Inc., Menlo Park, California, United States of America.
authors.forename: Cameron
authors.initials: C
authors.lastname: Marlow
authors.affiliation: Electrical and Computer Engineering Department, University of California San Diego, San Diego, California, United States of America.
authors.forename: Massimo
authors.initials: M
authors.lastname: Franceschetti
authors.affiliation: Department of Sociology, Yale University, New Haven, Connecticut, United States of America; Department of Medicine, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Christakis
authors.affiliation: Political Science Department, University of California San Diego, San Diego, California, United States of America; Medical Genetics Division, School of Medicine, University of California San Diego, San Diego, California, United States of America.
authors.forename: James H
authors.initials: JH
authors.lastname: Fowler
mesh_terms: D004644:Emotions; D006240:Happiness; D006801:Humans; D008962:Models, Theoretical; D060756:Social Networking