As social media has become a major mode of entertainment, subscribers have often turned to YouTube to fill hours of free time. People watch close to 5 billion YouTube videos every day, according to a press release, and popular channels have become an alternative to cable or streaming services such as Netflix or Amazon Prime.

If you’ve ever cried while watching a vlogger deliver a serious monologue, or if you’ve smiled as one of your favorite YouTube sensations has celebrated good news, you know just how powerful the video platform can be. But it turns out there’s science behind these responses to emotional online content that can help us all understand why our reactions are so in line with the person on our screen.

Researchers from Tilburg University in the Netherlands parsed through 2,083 YouTube vlogs selected from 110 vloggers and found that viewer comments on the videos often matched the emotional tenor of the vlogs themselves. If a vlog was especially upbeat, audience reaction was likely to match it. But if the vlog was a downer, the comments weren’t going to come from a positive emotional place, either.

There are two reasons for this phenomenon. One is what psychologists call “homophily” — people are attracted to content that reflects their moods and views. But while that’s a prolonged state, there’s also a more immediate impact called “contagion,” where people are being affected by others’ emotions in real time.

The researchers found evidence of both homophily and contagion among viewers who watched and commented on YouTube vlogs. That means that, while people are often pulled toward content that reflects their emotional state from the get-go, the vlog in question can also influence their mentality and inform their brain activity.

None of this may prove hugely shocking — just as we empathize with our friends when they tell us news about their lives, we tend to feel for the people on social media whom we follow. But it should put an even greater focus on the power of social media and how it influences our day-to-day, down to our very emotions.

Originally published on The Ladders.

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