In this election year, we’ve been treated to an abundance of political speeches. But have you ever listened to the crowd instead of the speaker? You’ll hear the din of the audience rising and falling in time with the rhetoric. The crowd is swept away with emotion – and, if it’s a great orator, that emotion will build and build.


The audience is responding not only to the speaker’s emotion but also to that of everyone around them. We humans are exquisitely social animals. We automatically take in a myriad of cues about other people and can often immediately detect what they’re feeling. Moreover, we often begin to feel what they’re feeling.

This is why angry mobs behave in ways that individuals might not. It’s also why movies seem funnier when you see them in a theater than when you’re watching at home. This phenomenon is called “emotional contagion.” We can literally “catch” an emotion from another person the way we catch the flu.

How we catch emotions

We begin to experience emotional contagion as babies. The pupils of infants six months to a year old dilate in response to images and sounds of other babies experiencing happiness and distress. (Our pupils dilate when we’re interested or excited.)

Just watch this mom playing her baby’s emotions like a piano:

This is probably an important survival mechanism, allowing children to better fit in with their families and societies.

Psychologist Elaine Hatfield first described the phenomenon, and she and her colleagues theorized that it’s partly the result of our unconscious mimicry of people with whom we’re interacting. If you’re talking to someone who’s sad, you’re likely to adopt a sympathetic expression – which looks pretty much like the sad expression your friend has.

Adopting a specific facial expression or body language like this, especially deliberately smiling or frowning, can change your mood. The exact mechanism isn’t clear, but scientists think that that going through the emotions of an emotion may send signals to the brain that actually evoke that emotion.

So it makes sense that whether you’re at a work meeting, having coffee with an acquaintance or on the convention floor, you would catch the moods of those around you.

The discovery of mirror neurons gave more weight to this theory. Mirror neurons fire in the brain when we watch someone else doing something. Some experts believe they explain why we feel empathy: Our mirror neurons literally are putting us through the same experience as the other person’s.

Happiness is contagious

Emotional contagion can affect our health long-term, for better or worse. On one hand, stress of any kind increases the body’s production of cortisol and over time this can lead to high blood pressure and heart disease. Simply hanging around with other people who are stressed-out or depressed can make us start to feel the same way.

On the other hand, warm connections with friends and family counteract the effects of stress, making us generally healthier as well as happier.

Researchers James Fowler and Nicholas Christakis found that happiness actually spreads in real-world social networks – among friends, family, neighbors or work colleagues. It may seem obvious that when a family member or friend becomes happy, you’d become happier. But the research found the same effect even when it was a friend of a friend who cheered up. Research subjects didn’t need to actually know the person whose happiness increased to feel the positive effects. (Sadness did not spread the same way.)

Even on social media

Some people may have a stronger influence on others’ emotions – while some of us may be more susceptible to catching emotion.

Any schoolteacher knows that classes have their own personalities. One group of first-graders may be attentive and productive, while another group is just wild. Researchers at the University of Reading in the UK think emotional contagion may explain this. And, in a somewhat scary approach, they’re going to use brain scans to try to identify the emotional instigators, according to the Daily Mail.

A 2015 study of Twitter users found that positive emotions were more viral than negative ones. It also showed that approximately 20 percent of users were four times as likely as average to be swayed by positive tweets, while another group was much less likely than most to experience emotional contagion. If you want to see where you fall on the spectrum, psychologist Sherrie Bourg Carter has posted the Emotional Contagion Scale. Take the quiz to see how susceptible you are.

Can your Facebook Feed affect your emotions?

Emotional contagion definitely takes place online, as was shown in the infamous Facebook experiment. Facebook researchers diddled with users’ news feeds on a massive scale. For some users, they reduced the number of negative posts; for others, they reduced the number of positive posts. When they saw fewer positive posts, Facebook users responded by posting more negative posts and vice versa. The experiment also found that when Facebook reduced the total amount of emotional posts people saw, those people were less expressive overall.

The experiment showed that we humans don’t need to be in the presence of someone else to be affected by their feelings; social media is quite enough to trigger our emotions.

All this gives new meaning to the concept of going viral, doesn’t it? When we’re sharing a meme, we’re also spreading emotion, for better or worse.

Emotional contagion can take down whole economies. Tyler Cowen, a professor of economics at George Mason University, argues that emotional contagion can affect entire countries. He notes, for example, that in bad times, the stock markets of different nations tend to move in synch. He writes, “Our peers influence our moods, but today’s peers are more global than ever because of social media and the spread of satellite and cable television. That could make a given mood swing in one nation or region more potent and further-reaching than before.”

It can also tank your company.

In part two, we’ll look at how you can harness the science of emotional contagion in the real world and also in all sorts of online interactions, from social selling to marketing to ecommerce to advertising.

Meanwhile, have a great day.