Why do people sing along?

The band gets to the chorus, and all at once the whole party is singing it, even the people who’d never sing on their own. It’s one of the best moments a party can have. A lot of people wonder why it happens, often with a song like Sweet Caroline in mind.

For a 2012 study, researchers spent 30 nights in five venues in the north of England, some with DJs and some with live bands, and counted how many people sang along to each of 1,054 songs.

The setting explained about 40% of the difference in how much people sang from one song to the next. People sang more later in the night, on weekends, in bigger venues, in younger crowds, and to songs that had spent four weeks or more in the charts.

The way a song was sung explained about another 25%. People joined in more on songs sung with a full chest voice and a lot of vocal effort, with clear consonants and few long runs of notes on one syllable. One observer did all the counting, though, and all the venues were in one part of England.

Part of it may be that knowing what’s coming feels good. In a 2011 brain-imaging study, researchers found that the brain releases dopamine, its reward chemical, while a listener is waiting for a favorite moment in a song, before that moment arrives. That was a small group of people listening to their own favorite music in a scanner, which is a long way from a concert.

Still, a chorus is the part of a song most people can feel coming, and that may be part of why it’s where a crowd joins in.

In two British studies, people who sang together felt closer fairly quickly. In the first, from 2015, 135 adults aged 18 to 83 started new adult-education classes in singing, crafts or creative writing. A month in, the singers felt closer to their classmates than the others did, and by the third month the other classes had caught up. People chose their own classes, though, and about half of them didn’t give answers at every stage.

It seemed to work in a big group of strangers, too. In the second study, from 2016, a London community choir sang for 90 minutes at a time, sometimes in small groups of 20 to 80 and sometimes all together as one choir of 232. People felt more connected afterwards either way, and the jump in closeness was bigger in the big choir, where most people didn’t know each other. Everyone in that study was singing, so there was no group doing something else to compare with.

The singers in both studies had signed up to sing, in a class or a choir, which isn’t quite the same as a crowd joining in on a chorus at a party. We still find them encouraging for a wedding or a company party where a lot of the guests are meeting for the first time.

Going by those studies, we’d lean on songs most of your guests already know, sung out clearly, and save a few of the biggest ones for later in the evening.

Two of our acts are built around singing along. With live band karaoke, a guest sings with a live band behind them. With a Beatles sing-along, two musicians lead the songs and everyone has the words, so nobody has to know the verses by heart.

If dancing is part of the plan too, check out our ideas on how to get people to dance at a wedding.