The study found that status messages that included negative feelings tended to get more responses. Posts annotated with a negative emotion got twice as many comments as the average user’s, and the comments tended to be longer. People also received more private messages after sharing their “negative feelings.”

“Teens tended to be more negative,” says Burke. “And that’s consistent with what we know about teens and cognitive development.”

The textual content of these messages and comments also tended to be more supportive than the average comment or message, Burke added. Researchers found this despite reading no comments in the study: Instead, they built a dictionary “by culling words from Hallmark cards” and websites that “provide examples of sympathy or condolences” and cross-checked this database with the words in the comments.

There’s no way to tell whether people annotated some emotions sarcastically, Burke said, “but you wouldn’t see the magnitude of these effects if it was just sarcasm.”

From this study, Burke infers that people tend to be explicitly supportive of negative emotions when they’re expressed on Facebook. This runs counter to findings in similar research on other social networks. A 2014 study found that people were less likely to respond to expressions of “severe, enduring loneliness” on Twitter than they would to the average tweet. (The researcher who led that study now works at Facebook.) These two findings point to important differences between Facebook and Twitter, said Burke: On Facebook, friendship is a mutually agreed-upon status, and you’re more likely to be friends with close confidants. On Twitter, you might be sighing into the void. But this study does not allow quite so tidy an inference. Only 8.1 percent of all English-language Facebook posts from Americans include a feelings annotation. The users who contribute to this 8.1 percent differ from Anglophone Facebook users generally: They are four years younger and 20 percent more likely to be women than the average; they also have more friends, log into Facebook more, and joined the social network more recently.

“It’s very clear from this paper that [Facebook and Twitter] are quite different as social ecosystems,” said Luke Stark, who researches emotions in social media at New York University and was not connected to the research.

He noted that the data wasn’t always as specific as it could have been. Researchers threw out an entire category of emotions to arrive at their final bifurcation of positive and negative feelings: The annotation tool allows users to say they’re feeling drunk, curious, or normal, but they don’t have as clear a valence and were excluded from the study, he said.

The study also “never talks about what proportion of Facebook users actually use [the feelings-annotation tool]. And they don’t actually talk about how frequently one might use it over time,” Stark told me. “How useful was this dataset to Facebook? My guess is not that useful.”