The news spread quickly: Taylor Swift is engaged! Fans of the singer immediately took to social media to share their personal reactions. Thousands of posts showed people screaming with joy or with tears in their eyes. One TikTok video — later reported to have been a skit — showed an American professor canceling an exam because, he said, neither he nor his students could possibly focus after hearing the news.

Certain themes recurred again and again, such as: "Why am I as excited as if it was my own engagement?" or "How am I meant to focus on work right now?"

Of course, many of the posts contain a certain amount of irony, self-mockery or exaggeration. And yet more than 28 million users liked Swift's Instagram post in just a single day.

What's behind the phenomenon of people feeling as emotionally invested in a celebrity's life as if this stranger were their best friend?

One-sided parasocial friendships

Developing friendly or romantic feelings for a stranger is known as a "parasocial relationship." It can happen with a megastar such as Taylor Swift, but also with internet personalities like a favorite influencer or podcast presenter. The psychologist Sonia Jaeger describes such relationships as "my friend who doesn't know me."

The concept of the parasocial relationship goes hand in hand with the growing popularity of reality shows on TV and social media. Years ago, all fans really knew about their idols were their projects such as movies or albums and a few details that might, for example, be revealed in interviews or an "at home" magazine spread.

These days we know far more about celebrities' private lives — their pets' names, their dating history, where they go on holiday, what health problems they're dealing with — either because the stars have shared the information themselves, or because they've been recorded by the multitude of smartphones pointed at them pretty much 24/7.

'No nutritional content'

Knowing so much information about a person can create an illusion of intimacy, Jaeger writes. If people know the names of Swift's cats, how many times her mother has beaten cancer, and how many relationships she's had in the past — some of them toxic — it's no wonder they're happy to hear that she's engaged.

The need to feel connectedness with others is part of human evolution. "Humans have evolved to thrive in groups, probably because 250,000 years ago you needed to rely on other people to survive by building social relationships," writes Arthur C. Brooks, a professor of sociology at Harvard University. "And so we become attracted to and care about people if we have a regular enough exposure to them." This is the case whether this exposure happens in real life or in an update on Instagram.

There's no single answer as to whether parasocial relationships are good or bad. There's nothing wrong with being happy about the engagement of a global pop star and a competitive sportsman if the event is just a distraction from all the bad news currently dominating the international media.

Being part of a community of fans who share an interest in the life and work of a particular person and like to discuss them among themselves can help people feel less lonely. Sonia Jaeger writes that, because parasocial relationships take place wholly online, "especially during the COVID-19 pandemic, this kind of relationship may have helped us satisfy our universal need for human connection."

Experts say parasocial relationships can never replace reciprocal relationships "in real life." Celebrities such as Swift and Travis Kelce don't reciprocate their fans' affection at an individual level. Brooks says such relationships are like fast food: "They taste good, but they have no nutritional content and won't meet your needs."

Or to put it another way: Taylor Swift isn't going to congratulate you when you post the news of your own engagement on Instagram. For that, we need real friends who will be happy for us, and who reciprocate the affection we feel and express for them.

This article was been originally written in German.