Chicken pox, the flu, and strep throat: these are all common health ailments often associated with being highly contagious. Just as these illnesses can be contagious, emotions can be too. The concept of emotional contagion is when the emotions of one person can be passed along to another person. Research has shown that people can, in fact, transfer positive and negative emotions to one another.

In the beginning of June 2014, a study entitled, “Experimental evidence of massive-scale emotional contagion through social networks” was published online in the Proceedings of the National Academy of Sciences (PNAS). The study’s authors, Adam Kramer of Facebook, Jamie Guillory of University of California and Jeffrey Hancock of Cornell University, have faced a lot of criticism in the media in recent weeks as a result of this research.

The goal of their study was to test if emotional contagion could be observed in interactions that are not in-person.  By manipulating the News Feed of a little more than 689,000 Facebook users, the researchers were trying to see whether exposure to emotions via News Feed posts influenced others. This tested whether exposure to certain emotions on someone’s News Feed would lead one to subsequently change their own posting behaviors. The emotional content of these posts were evaluated to see “whether exposure to verbal affective expressions leads to similar verbal expressions, a form of emotional contagion.”

After analyzing over 3 million posts from one week in January 2012, out of the 122 million words posted, 4 million were positive (3.6%) and 1.8 million were negative (1.6%). The researchers found that those individuals who had the positive content reduced in their News Feed had status updates with larger percentages of negative words and a smaller percentage of positive words. The opposite pattern was observed for those whose News Feed had the negative content reduced.

This research also showed that textual content alone is enough to spread emotions. Meaning, neither direct interaction nor nonverbal behavior need be present to influence the emotions of another person.

This research has greater implications for public health, as technology is only becoming more integrated into our daily lives.

A lot of research has been conducted showing the connection between negative emotions and their effect on the body. Consistent stress and fear can result in immense wear-and-tear on the body. It can eventually lead to stroke, heart disease and diabetes. Prolonged anger and anxiety can also lead to dangerous heart conditions by changing the electrical stability of the heart.   A major study done in Canada in 2004 found that people reporting high levels of psychosocial distress had equal risk of heart disease as smokers.

On the other hand, positive emotions can have a positive effect on health. Recent research has found that psychological well-being resulted in decreased risk of hypertension. Other benefits of emotional positivity include better immune systems, better sleep, and faster recovery from cardiovascular stress.

At the intersection of technology and data security comes the question of our health implications. Despite the criticism the recent research has been receiving, its results begin to shed some light on how our online activity can influence the emotional health of others. With its 1.3 billion users, Facebook has a plethora of information and data in its purview. The Facebook Data Science team can prevent future negative responses, such as occurred in this most recent study, if they have greater oversight and regulation. The Team has the opportunity to be at the forefront of the effect our online social activity can have on our physical and emotional well-being.