> In an academic paper published in conjunction with two university researchers, the company reported that, for one week in January 2012, it had altered the number of positive and negative posts in the news feeds of 689,003 randomly selected users to see what effect the changes had on the tone of the posts the recipients then wrote.
> The researchers found that moods were contagious. The people who saw more positive posts responded by writing more positive posts. Similarly, seeing more negative content prompted the viewers to be more negative in their own posts.
I will add they did this experiment partially in response to an academic study that found viewing happier posts on Facebook made people sadder (explained mostly by FOMO).
FB was trying to refute that, and their study was more technically rigorous, but the outcome they were measuring doesn't actually refute the original claim at all IMO. People writing more happy posts on FB does not indicate they are actually happier, it could also be that they wish to broadcast more of their happy moments, or perhaps even just pretend to be happier, in response to the attitude of their feed.
Remember this one?
https://www.nytimes.com/2014/06/30/technology/facebook-tinke...
> In an academic paper published in conjunction with two university researchers, the company reported that, for one week in January 2012, it had altered the number of positive and negative posts in the news feeds of 689,003 randomly selected users to see what effect the changes had on the tone of the posts the recipients then wrote.
> The researchers found that moods were contagious. The people who saw more positive posts responded by writing more positive posts. Similarly, seeing more negative content prompted the viewers to be more negative in their own posts.