Does your Facebook feed seem especially glum lately? Angry? Bubbly? Streaks like that are to be expected, according to a new study from Facebook data scientist Adam Kramer. After analyzing posts by roughly 1 million users and their 150 million friends, Kramer has concluded that emotions spread like wildfire across the social network. Use an especially emotional word such as “happy” or “hug” or “wretched,” and your friends are liable to express similar emotions for up to three days, the San Jose Mercury News reports.
“Up to three days later, for people who use more negative words, their friends will also use more negative words,” Kramer says. “If people are using more positive words, not only are their friends using more positive words, their friends also will use fewer negative words.” Psychologists have long known that emotions are contagious in face-to-face interactions, but this study suggests that they can spread even without such cues as tone of voice or facial expression.