Emotions spread like a contagion on social networking sites such as Facebook, a new study suggests.
According to scientists at Cornell, the University of California, San Francisco (UCSF), positive emotions expressed via social networking sites make people happy.
For the study, researchers tweaked Facebook news feed of 689,003 randomly selected users. Researchers were looking for the "emotional contagion." The team deliberately reduced or increased the number of positive news from the participants' news feed.
They found that the emotional contagion works both ways: people who saw more positive news tended to express positive emotions via positive status updates, while those who saw negative updates were more likely to express negative emotions.
"People who had positive content experimentally reduced on their Facebook news feed, for one week, used more negative words in their status updates," said Jeff Hancock, professor of communication at Cornell's College of Agriculture and Life Sciences and co-director of its Social Media Lab. "When news feed negativity was reduced, the opposite pattern occurred: Significantly more positive words were used in peoples' status updates."
Emotional contagion is quite evident in the real world: a happy person is more likely to spread cheer where as a grumpy person makes others' lives miserable. This is the first time that researchers have found the contagion in a social networking platform.
Facebook's new algorithm constantly filters out stories to suit each person's tastes. Researchers found that with the tweaking - the news feed was not only enough to make a user happy or sad, but could also be used to influence moods of people associated with the study participants.
Researchers didn't see the posts, but looked for positive or negative words in the updates. They found four million positive words and 1.8 million negative words from a data of 3 million posts containing 122 million words.
"This observation, and the fact that people were more emotionally positive in response to positive 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 news release. "In fact, this is the result when people are exposed to less positive content, rather than more."
The study is published in the journal Proceedings of the National Academy of Science.
Previous research has shown that Facebook is addictive, sometimes even more than sex. Other studies have associated Facebook use with anxiety, debt and even higher weight.