Experimental evidence of massive-scale emotional contagion through social networks
Adam Kramer, Jamie Guillory and Jeffrey Hancock reported an experiment on 689,003 Facebook users in which the emotional content of the News Feed was altered. The authors concluded that emotional states can be transferred to others through emotional contagion, often without people noticing, and that contagion can occur without direct interaction between people and without nonverbal cues. The effects were small.
Adam Kramer, Jamie Guillory and Jeffrey Hancock reported an experiment on 689,003 Facebook users in which the emotional content of the News Feed was altered. The authors concluded that emotional states can be transferred to others through emotional contagion, often without people noticing, and that contagion can occur without direct interaction between people and without nonverbal cues. The effects were small.
Written from the crossref abstract record, read 2026-10-23; effect sizes as reported in the full text.
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doi:10.1073/pnas.1320040111. Effect sizes as reported in the full text.