How Facebook can alter your mood: Concerns raised over study of ‘massive-scale emotional contagion’

facebook212Researchers from Facebook and Cornell University altered the contents of Facebook users’ news feeds to test the effects of positive and negative posts, finding evidence that emotions can spread through an online community much as they do in real life.

“When positive expressions were reduced, people produced fewer positive posts and more negative posts; when negative expressions were reduced, the opposite pattern occurred,” the researchers say in their newly published paper. “These results indicate that emotions expressed by others on Facebook influence our own emotions, constituting experimental evidence for massive-scale contagion via social networks.”

It’s a fascinating finding, but the manner in which the study was conducted is raising concerns among some academics and Facebook users. The Atlantic dug into the issue over the weekend, asking whether Facebook’s terms of use constituted informed consent by users who were included in the study.

The study raises broader concerns about the potential for the social network to use the findings to manipulate moods on a broader scale.

Adam Kramer, the Facebook data scientist who led the study, defended the research in a post over the weekend.

Regarding methodology, our research sought to investigate the above claim by very minimally deprioritizing a small percentage of content in News Feed (based on whether there was an emotional word in the post) for a group of people (about 0.04% of users, or 1 in 2500) for a short period (one week, in early 2012). Nobody’s posts were “hidden,” they just didn’t show up on some loads of Feed. Those posts were always visible on friends’ timelines, and could have shown up on subsequent News Feed loads. And we found the exact opposite to what was then the conventional wisdom: Seeing a certain kind of emotion (positive) encourages it rather than suppresses is.

And at the end of the day, the actual impact on people in the experiment was the minimal amount to statistically detect it — the result was that people produced an average of one fewer emotional word, per thousand words, over the following week.

If you’re a Facebook user, how do you feel about all of this? Positive or negative? Be careful which sentiment you express if you post this story to your timeline — the impact of your words could be more significant than you might think.