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You're scrolling down your Tumblr dash, when you see an impossible piece of news about your favorite TV show. It sounds too good to be true, but you click anyway. And there he is in all his glory, Rick Astley, singing about how he's never gonna give you up. You've been rick-rolled, and the worst part is, you know that song is gonna stay with you the rest of the day, a short snippet repeating itself over and over until you wanna tear your ears out.

You've got yourself an earworm: a repeating snippet of music, probably fifteen to twenty seconds long, that's playing in your head without you consciously making it happen. But why? How do songs get themselves stuck in your head? More importantly, how do you get rid of them?

It turns out that which song gets stuck mostly depends on the person. But psychologists have some ideas about why your brain puts its playlist on repeat, and there are a few ways to hit pause, including bubblegum and word puzzles.

The term "earworm" entered the English language pretty recently, sometime in the 1970s, by way of the German word, "Ohrwurm," which means the same thing. But the actual phenomenon of getting a song stuck in your head is much older. Centuries old references call it, "The Piper's Maggot." To study it, scientists usually use the term, "involuntary musical imagery," or INMI for short, because earworms are linked to other kinds of involuntary thoughts.

A lot of our conscious thoughts are involuntary, like 30-40% of them, but psychologists don't know much about how they work. Within the last five years or so, researchers have realized that earworms are a good place to start because they're a little more concrete and therefore easier to study than other kinds of spontaneous thoughts, which first meant figuring out how widespread earworms are, how they happen, and whether some people get them more than others.

Earworms are incredibly common. More than 90% of people report having them. The songs usually have lyrics, as opposed to being instrumental, and live music is more likely to stick in your brain than recorded music, maybe because it includes a visual element or because you're so excited and emotional from seeing your favorite band right there on the stage.

But even though having a song stuck in your head seems like it wouldn't be a good time, that's not necessarily true. Roughly three-quarters of people who report having earworms actually like, or at least don't really care about, the song in their heads. The annoying tunes don't happen as much, but we remember them more because...well, they're annoying. If an experience is more stressful, it's more likely to stick in your memory, which is probably why you remember that one commercial jingle or Rick Astley.

Now, if you listen to a lot of Top 40, you're probably gonna get a lot of Taylor Swift songs stuck in your head. But you can't get a Led Zeppelin earworm if you've never heard Jimmy Page play guitar. This is why earworms tend to be songs that you know and like--you listen to them more.

You might think that certain songs are catchier than others, so they can be more intrusive. Well, that's an easy hypothesis to test, because scientists do know some of the characteristics that make a song catchy. Long notes that are close together in pitch, for example, like in the chorus of the ABBA song, "Waterloo."

In a series of papers published in 2012, a British musical psychologist named Victoria Williamson led a research group that spent some time studying earworms. They asked people to describe the songs stuck in their heads and they found that very few songs occurred more than once. People did tend to report songs like "Jingle Bells" around the holidays, and pop songs that were constantly on the radio showed up a lot more in the answers too, but every other song was unique, even though they surveyed thousands of people. So which song gets stuck in your head just seems to depend on who you are, your musical taste, and your personal memories. That's because there are a bunch of different ways to get an earworm, and some of them depend on your individual personality.

In another part of the study, Williamson and her team partnered with the BBC, surveying radio listeners to try to figure out what gave them earworms. Unsurprisingly, the most common cause was recent or repeated exposure to a song, so Top 40 and "Jingle Bells." But there were a few others too. The researchers found that earworms can be associated with a particular memory, and calling up that memory would also dredge up the song. It can even work in reverse, like if you're going to a concert, you might get the band's song stuck in your head ahead of time.

Certain moods, like stress or surprise, can make particular songs get stuck in people's brains. They also found that earworms can happen when your mind isn't working very hard, like when you're daydreaming, or even when you're actually dreaming when you're asleep. Apparently it's pretty common to wake up with a song already stuck in your head.

So, we know what kinds of things can cause earworms, but why do our brains get fixated on songs at all? Scientists still aren't exactly sure, but they think it's related to what's known as the Zeigarnik effect.

Bluma Zeigarnik was an early 20th century Soviet psychologist who noticed that servers could flawlessly remember a customer's order right up until the order was delivered. Once the task was done, the memory went kaput. Zeigarnik spent time studying this effect and found that people who were interrupted in the middle of doing something could remember what they were doing much better than people who were allowed to finish. In other words, your brain works hard to keep a task that's in progress in your working memory. But once you're done, it doesn't need that information anymore, so it tosses it out. That can help with productivity, since if you start something, your brain is gonna keep it on the front-burner until you finish it. In other words, listen to Shia LaBeouf: JUST DO IT!

When it comes to earworms, your brain might be considering an intrusive song to be an unfinished task. Also in 2012, one group of researchers at Western Washington University tested this by giving their study participants earworms. They played songs by The Beatles and Lady Gaga and either let them finish or stopped the song in the middle. The songs that they paused didn't come back as earworms more than the finished ones, which would seem to be a point against the Zeigarnik effect. But they noticed something interesting: if participants heard the song playing in their heads right after listening to it, it was more likely to come back as an earworm sometime in the next 24 hours. The researchers interpreted this as evidence in favor of the Zeigarnik effect, proposing that the participants' brains were treating those songs as unfinished tasks.

So if your brain thinks it's an unfinished task, how do you get the local car dealership's jingle out of your head? A few studies have come up with different strategies. One of the strangest ideas is to just chew gum, which might somehow interfere with the same processes your brain is using to play the song. Most of the others take into effect the Zeigarnik effect, plus the fact that earworms tend to have lyrics.

One survey by Williamson's group in the U.K. and a psychologist named Lassi Liikkanen from Finland combined data from thousands of participants and examined the way people already responded to earworms. They found that people tried two main things: distraction and engagement, both of which seemed to work.

Distractions that were kind of similar to the earworm were most effective, like listening to a similar song. Some participants even reported listening to so-called "cure songs." Not like the band, The Cure, though that could work, but particular songs that people said would push their earworm out without becoming earworms themselves. The researchers couldn't explain why these specific songs didn't become earworms since virtually any song can, but they didn't.

Engagement, on the other hand, tries to take advantage of the Zeigarnik effect. Lots of people know the first verse and chorus of songs, but they might not know the second verse, so their brains can't complete the task and the chorus gets stuck in an infinite loop. That's why engaging with the song by singing along or listening to it often made it go away. Though the researchers did note that a lot of people liked their earworms enough to not bother doing anything about them.

But it was that 2012 Lady Gaga/Beatles study out of Western Washington that had the most interesting solution to the earworm problem. The study was broken up into a few different experiments. In each, the researchers would play either Top 40 songs by Beyoncé, Taylor Swift, and Lady Gaga or classics by The Beatles in a certain order. The participants were then asked to solve a puzzle. In one experiment, these were Sudoku puzzles; another used anagrams. While they were solving the puzzles, the songs would tend to pop back into their heads. The researchers wanted to know if the difficulty of the puzzles would make a difference in the songs becoming earworms and whether it mattered if the puzzles involved letters or numbers.

Turns out, both of those things were important. Puzzles that were too easy weren't distracting enough to push the involuntary songs out of people's brains, but neither were puzzles that were too hard. That might seem counterintuitive unless you've ever played a tough level in Candy Crush and just given up in disgust. When a task is too challenging, you can lose interest, and the earworm sneaks back in. Moderately difficult puzzles seemed to hit the sweet spot, taking up just enough mental resources for people to forget about the intrusive song. Also, the word puzzles worked better than the number puzzles, something that a bunch of earworm studies have noticed.

The researchers think that's because most earworms are songs that have words, so your brain treats them as a type of verbal task, but when it's time to solve the word puzzle, your brain needs to use the same resources, so it dumps the earworm to focus on solving the puzzle.

So there you have it. Next time you have an earworm you need to get rid of, solve a somewhat difficult anagram. But, in case you don't carry those around with you all the time, the researchers suggest just reading something, as long as it's engaging enough to push the earworm out of your working memory.

And if you find yourself getting earworms a lot, there's no need to worry. Music is everywhere, piped into department stores, elevators, out of your phone when you're on hold with customer service for two hours... It's no wonder we get songs stuck in our heads when we hear them constantly. And it's also possible that we've trained ourselves to have a good memory for music because oral traditions go back far longer than any writing system. For a long time, humans used songs to remember things on purpose.

So the next time you're hearing some '80s one-hit-wonder for 36 hours straight, it's not that there's something wrong with your brain. Your brain's just really into music.

Thanks for watching this episode of SciShow, and thanks especially to our patrons on Patreon. See you next time.

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