We show, via a massive (N = 689,003) experiment on Facebook, that emotional states can be transferred to others via emotional contagion, leading people to experience the same emotions without their awareness. We provide experimental evidence that emotional contagion occurs without direct interaction between people (exposure to a friend expressing an emotion is sufficient), and in the complete absence of nonverbal cues.
情绪状态可以 通过情绪感染而传递，这导致人们无意识中体验到了同样的情绪。在实验室实验中情绪感染得到了很好的建立，人们将积极和消极的情绪传递给了别人。我们通过现实世界大型社交网络所收集的20年间的数据表明，虽然结果富有争议，持久情绪（如抑郁，幸福）可以通过网络传输[Fowler JH, Christakis NA (2008) BMJ 337:a2338]。在一项Facebook使用者的实验中，我们通过在新闻联播中减少情感内容数量来测试情绪感染是否能在人与人相互作用外的个人之间发生。当积极性表达降低后，人们发布的积极帖子数降低而消极帖子数量有所增加；而消极表达降低之后，人们发帖情况则与此相反。这些结果表明我们的情绪会受Facebook上他人情感的影响，这通过社交网络构成了大规模感染实验证据。这项工作还表明与当初假设相反，人与人之间的互动和非语言暗示不是情绪感染所必须的，并且浏览他人积极经验会构成人们的一种积极体验。
Emotional states can be transferred to others via emotional contagion, leading people to experience the same emotions without their awareness. Emotional contagion is well established in laboratory experiments, with people transferring positive and negative emotions to others. Data from a large real-world social network, collected over a 20-y period suggests that longer-lasting moods (e.g., depression, happiness) can be transferred through networks [Fowler JH, Christakis NA (2008) BMJ 337:a2338], although the results are controversial. In an experiment with people who use Facebook, we test whether emotional contagion occurs outside of in-person interaction between individuals by reducing the amount of emotional content in the News Feed. When positive expressions were reduced, people produced fewer positive posts and more negative posts; when negative expressions were reduced, the opposite pattern occurred. These results indicate that emotions expressed by others on Facebook influence our own emotions, constituting experimental evidence for massive-scale contagion via social networks. This work also suggests that, in contrast to prevailing assumptions, in-person interaction and nonverbal cues are not strictly necessary for emotional contagion, and that the observation of others’ positive experiences constitutes a positive experience for people.