Facebook recently revealed it carried out a week-long experiment back in January 2012 on nearly 700,000 users to test the effects of positive and negative posts, according to a paper published by the PNAS journal.
The feeds belonged to 689,003 users of the English version of Facebook. The experiment was designed to determine “whether exposure to emotions led people to change their own posting behaviors,” wrote a team of Facebook scientists.
Actual posts were not affected and could still be viewed from friends’ profiles. The experiment only changed what selected users saw in their News Feed, which is governed by a Facebook algorithm.
According to the study, there was one track for those receiving more positive posts and another for those who were exposed to more negative content from their friends.
The experiment’s results of the experiment showed emotion in posts is contagious. Those who saw positive content were more positive and less negative in their activity. The reverse was true for people tested with negative postings.
“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.”
While users may not have been aware they were part of the experiment, Facebook was able to conduct the study because all users must agree to the social network’s terms and conditions. Those conditions include “internal operations, including troubleshooting, data analysis, testing, research and service improvement.”
Read more: PNAS journal