The science of why sea shanties are so catchy

There are a lot of things about the world in 2021 that would have surprised us a year ago, but one of the more pleasant ones is definitely the rise of the sea shanty.

On social media, and TikTok in particular, sea shanties have exploded in popularity. Nathan Evans, a postie from Airdrie, Scotland, posted a video of himself singing the shanty Wellerman, and others began to join in, adding harmonies and instrumentals.

The trend isn’t confined to social media. Bristol-based shanty band The Longest Johns have entered the Top 40 in the UK singles chart with their rendition of Wellerman, and have hit number 1 on Spotify’s viral charts in 19 countries.

Naturally, we here at BBC Science Focus wanted to know what it was about sea shanties that makes them so catchy. So we spoke to Prof Catherine Loveday, a neuropsychologist who specialises in music at the University of Westminster.

What is a sea shanty?

Sea shanties are work songs that were created by sailors aboard merchant ships, usually sung in accompaniment of hard labour such as hoisting the sails or raising the anchor.

“They're very, very repetitive and fairly upbeat, uplifting tunes and melodies that people can very quickly join and sing together,” says Loveday. “The melody and the rhythm are designed to match the activities that are going on.”

Why do work songs help with hard labour?

Part of what makes work songs useful is simply keeping everyone in time with each other: everyone pulls on the rope to the beat of the music, and the work becomes physically much easier.

But it’s not just that. A simple chant of ‘heave-ho’ or ‘one, two, three’ could keep people in time. The musical element helped people to bond and work better as a team, Loveday says.

“Music has a real capacity to connect us. It taps into our own natural communication system. It makes us feel bonded and connected,” she says. “It also lifts us up. In the same way as chanting at a football match or singing in a religious setting or even singing lullabies to children, music enables us to reach a different emotional state.

“We just seem to be primed to respond and connect better when there is melody and timbre and rhythm and all these elements of music added to something.”

This sense of togetherness provided by music has been useful all through human history. “Some people have argued that not just singing, but marching together and sort of collective rhythmic activities might even be a small part of our evolutionary success,” Loveday says.

“It feels like we're all working towards the same goals and we're working in the same direction. And actually human beings only exist when they work together. They only survive if they work together.”

Read more about music psychology:

• Music: How it affects your brain, changes your mood and helps you focus
• Why does music make us feel good?

What makes sea shanties good work songs?

“I think it's the fact that they tend to have these lifting, lilting melodies that go up and they tend to match the actual physical action you're doing,” Loveday says. The music rises with an upward movement, and falls with a downward one.

“We know from other research that people use music almost as a metaphor for something,” she adds. “So you sometimes in music have a sense of going home when something resolves. But you also have a sense of tension sometimes when something feels like it hasn't got home.

“What you have with sea shanties is something that that is almost moving you backwards and forwards in a very rhythmic sense. It's taking you away and it's bringing you back and it's taking you away and it's bringing you back.

“And it does that kind of with this very, very consistent rhythm, but also with sort of melodic lines that tend to go up and down and match the activity that you’re doing. And also in terms of a sea shanty, it kind of matches the environment that you're in, right?”

Why is Wellerman so catchy?

The jury is still out on what exactly makes a song catchy. That said, there are a few things that all good earworms have in common.

The easier the tune is to pick up, Loveday says, the more likely it is to get stuck in our heads. “So if we can if we can articulate it in our heads, so if we can kind of almost hum it internally or mouth the words, then we may be more likely to remember it better.

“Something that doesn't jump about too much but follows a nice line – those seem to be the things that stick in our mind most.” In the case of Wellerman, the chorus stays within one octave, so most people could sing it comfortably without stretching their range.

Repetition is also key. “Anything where you've got a repeated theme that goes round and round and round and it's very easy to sing back,” Loveday says. “Anything that is repeated like a mantra just kind of gets stuck.”

Wellerman has a call-and-response structure, with a soloist singing the verses, and the rest of the group joining in for the chorus – which comes around plenty of times in the song. A listener can join in with the chorus easily enough after only a few verses.

Songs in general tend to be catchier than instrumental music, just because of the way our brains are built.

“We remember tunes that are sung better than tunes that are played. And it's partly because you can, in your minds, sing it back. So you are kind of almost rehearsing and practising it,” says Loveday.

“[One] theory is that it's simply that the human voice compels us more. We are more intuitive and we've evolved to focus on the human voice.

“The other theory is this idea that if you can articulate it and if you hear something that you can mimic, even if it's just ‘la la la’, then you are more likely to remember it than if it's a violin or a flute that that we feel one step removed from.”

Why are sea shanties so popular right now?

It could be because music helps us to bond with each other. “I thought about this a lot when the Clapping for Carers started,” Loveday says. “And this was something that you saw actually all over the world, people started to use music and rhythm to connect to each other.

“I think this is what's happening with the sea shanties. I think people like to engage in collective musical activities and it's been completely impossible. But with a sea shanty, they're very, very easy to pick up.

“Very quickly, it becomes something that you can sing along with. And if you're singing along with it, then you're immediately engaged and you're part of it. And that in itself connects you to everyone else that's doing it.”

Read more about earworms:

• 'Uncertainty and surprise' the scientific secret to good pop music
• Why earworms get stuck in your head