Your Moods On Facebook Affect Your Friends

The Debbie Downers in your Facebook News Feed are messing with your mood.

A team of social scientists from Cornell University, the University of California, San Francisco and Facebook released a study detailing how your emotions expressed in posts and status updates can actually "spread" to your friends.

The team randomly selected 689,003 of Facebook's 1.3 billion total users, and manipulated their News Feeds. Some experienced a reduced amount of positive news on their feeds, while others experienced a reduced amount of negative news.

Users with reduced positive news began to use more negative words, and users with reduced negative news used more positive words, according to Jeff Hancock, a professor at Cornell’s College of Agriculture and Life Sciences and co-director of its Social Media Lab.

In addition to the "contagion" effect, the team also noticed a withdrawal effect, where people exposed to fewer emotional posts tended to post less expressive updates.

“This observation, and the fact that people were more emotionally positive in response to positive emotion updates from their friends, stands in contrast to theories that suggest viewing positive posts by friends on Facebook may somehow affect us negatively,” Hancock said in a statement. “In fact, this is the result when people are exposed to less positive content, rather than more.”

Previous experiments have suggested that this "emotional contagion" was applicable to real-life situations — that is, interacting with an extremely happy person will make you happier. But the Cornell study suggests that the contagion also applies when people are exposed to emotion, not just when they are experiencing an interaction.

Due to Facebook's data-use policy, the researchers never saw the content of the posts, but instead counted the amount of positive and negative words in more than 3 million posts with a total of 122 million words. According to the report, 4 million words were positive and 1.8 million were negative.

The study was published on June 2 in PNAS (Proceedings of the National Academy of Science) Social Science.