You probably never thought you would have to worry about Facebook being emotionally manipulative. But according to forbes.com, in 2012, Facebook conducted an Emotional Contagion study on almost 700,000 of its users.   

Facebook’s data scientists manipulated the amount of positive and negative posts in participants’ feeds in order to see how it affected their activities. Data scientist Adam Kramer and his research team discovered that the users’ emotions were contagious. When the amount of positive posts in a user’s feed was reduced, he or she posted less positive content. When the number of negative posts in a user’s feed was reduced, the user posted more positive content. Facebook’s researchers also noted that when they removed all emotive posts from a participant’s feed, they became “less expressive,” meaning they posted less status updates. 

Facebook’s researchers published a paper on their study in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) titled “Experimental evidence of massive-scale emotional contagion through social networks,” and discussed the influence that social media has over users’ moods. 

“[The] results indicate that emotions expressed by others on Facebook influence our own emotions, constituting experimental evidence for massive-scale contagion via social networks,” the team said. 

Though performing the study was legal, users questioned whether it was ethical. After Facebook revealed the experiment’s results, they received backlash for not informing the participants in a more direct manner. The participants did not sign up for the experiment. However, the Facebook’s Data Use Policy states that they “may use the information we receive about you…for internal operations, including troubleshooting, data analysis, testing, research and service improvement.”