Facebook conducted an experiment into how content can affect emotions by manipulating the feeds of over 600,000 unsuspecting users.
The ‘Experimental evidence of massive-scale emotional contagion through social networks’ paper was recently published and explained that Facebook changed the tone of feeds by skewing the number of positive and negative terms seen.
Facebook then monitored the effect it had on users’ emotions.
"The results show emotional contagion," wrote the team of Facebook scientists in the paper.
"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."
Facebook was able to carry out the experiment in January 2012 without informing the 600,000 users of their involvement as they had ticked a box agreeing to the social network’s terms and conditions which include "internal operations, including troubleshooting, data analysis, testing, research and service improvement."
However, Facebook points out that an algorithm picked out positive and negative posts, meaning no personal information or user data was viewed by human researchers.