If you’ve spent much time on Facebook, Twitter or other social media, you’ve probably noticed how quickly emotions—pride, happiness, disappointment, incredulousness—can spread throughout the online community. What’s curious is that one sentiment travels faster than others, say researchers at Beihang University in China.

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They gauged various online emotions by tracking emoticons embedded in millions of messages posted on Sina Weibo, a popular Twitter-like microblogging platform. Their conclusion: Joy moves faster than sadness or disgust, but nothing is speedier than rage. The researchers found that users reacted most angrily—and quickly—to reports concerning “social problems and diplomatic issues,” like a 2010 incident where a tainted food additive was believed to cause a neurodegenerative disease or when an international shipping dispute prompted an eruption of nationalist rage against Japan.

In many cases, these flare-ups triggered a chain reaction of anger, with User A influencing Users B and C, and outward in a widening circle of hostility, until it seemed all of Sina Weibo was burning. The users, according to the study’s authors, passed along these messages not only to “express their anger” but to instill a similar sense of outrage among other members of their online community on Sina Weibo—one of the only venues where the Chinese can circumvent government restrictions on traditional forms of media.

Jonah Berger, a professor of marketing at the Wharton School at the University of Pennsylvania, reached a similar conclusion after conducting a study in the United States. “Anger is a high-arousal emotion, which drives people to take action,” he says. “It makes you feel fired up, which makes you more likely to pass things on.”

Berger and a colleague analyzed 7,000 New York Times articles published during a three-month period to see which ones made the most-emailed list. The likelihood of content going viral had less to do with the positive or negative tone of an article, they say, and more to do with how activated the person felt after reading it. Sadness, they observed (perhaps unsurprisingly), was a “deactivating” emotion. Unlike anger, people tend to power down and withdraw—which is why melancholy feelings don’t spread very far or very fast among online communities.

The one emotion that outpaced anger in Berger’s study was awe, the feelings of wonder and excitement that come from encountering great beauty or knowledge, such as a news report of an important discovery in the fight against cancer. “Awe gets our hearts racing and our blood pumping,” Berger says. “This increases our desire for emotional connection and drives us to share.”