Detecting Emotional Contagion in Massive Social Networks

Lorenzo Coviello,Yunkyu Sohn,Adam D I Kramer,Cameron Marlow,Massimo Franceschetti,Nicholas A Christakis,James H Fowler,Renaud Lambiotte

doi:10.1371/journal.pone.0090315

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.

Highlights

Happiness and other emotions have recently been an important focus of attention in a wide range of disciplines, including psychology, economics, and neuroscience [1,2,3,4]
Experiments have demonstrated that people can ‘‘catch’’ emotional states they observe in others over time frames ranging from seconds to months [6,7], and the possibility of emotional contagion between strangers, even those in ephemeral contact, has been documented by the effects of ‘‘service with a smile’’ on customer satisfaction and tipping [8]
Longitudinal data from face-to-face social networks has established that emotions as diverse as happiness [9], loneliness [10], and depression [11] are correlated between sociallyconnected individuals, and related work suggests that these correlations exist online [4,12,13,14,15]

Summary

Introduction

Happiness and other emotions have recently been an important focus of attention in a wide range of disciplines, including psychology, economics, and neuroscience [1,2,3,4]. The key variable allowing us to estimate contagion in emotional expression is c, and our inclusion of the individual-fixed effect fj means that we are controlling for all possible characteristics of the person, which further reduces the likelihood that correlation in emotions is driven by choice of social connections (homophily).

Results

Conclusion