Mood statuses shared on Facebook are contagious, positive ones being the most influential, a new study finds.

You may not catch a cold online but you can definitely catch a mood. So suggests the findings of a new study conducted by University of California, San Diego researchers. According to them, mood statuses and feelings shared on Facebook are contagious. A good mood status leads to readers posting their own positive comments while a bad mood produces negative ones.  Interestingly, positive feelings and moods are more influential on the site than negative ones.

"Our study suggests that people are not just choosing other people like themselves to associate with but actually causing their friends' emotional expressions to change," said lead author James Fowler at UC San Diego in a press release. "We have enough power in this data set to show that emotional expressions spread online and also that positive expressions spread more than negative."

Researchers are not ignorant of the fact that emotions can spread among humans through direct contact like meeting face to face. However, there have been no studies that focus on whether the same is possible through online contact. Fowler is of the opinion that since social media has become such a huge part of our lives, it is important to know the extent to which it influences us.

For the study, Fowler and his team analyzed anonymous English-language status updates on Facebook in the top 100 most populous cities in the U.S. over 1,180 days, between January 2009 and March 2012. They used a software program called the Linguistic Inquiry Word Count to measure the emotional content of each post. The software facilitated researchers to avoid looking at the users' names and the actual content of each post.

Researchers then conducted a further experiment to determine whether there were any casual relationships involved. They found that during rainy days, the number of negative posts increased by 1.16 percent and positive ones decreased by 1.19 percent. To make sure that it wasn't just the rain that was resulting in more negative posts, researchers only took into account a user's friends that were in regions where it was not raining.

They found that each additional negative post yielded 1.29 more negative posts among one's friends, while each additional positive post yielded an additional 1.75 positive posts among friends.

"It is possible that emotional contagion online is even stronger than we were able to measure," Fowler said, according to CNet. "For our analysis, to get away from measuring the effect of the rain itself, we had to exclude the effects of posts on friends who live in the same cities. But we have a pretty good sense from other studies that people who live near each other have stronger relationships and influence each other even more. If we could measure those relationships, we would probably find even more contagion."

The study was funded by Army Research Office Grant, the National Institute for General Medical Sciences and the Pioneer Portfolio of the Robert Wood Johnson Foundation.

Findings were published online in PLOS ONE.