The song that never ends: The science behind earworms

It's a scenario we know all too well during the hustle and bustle of Christmas shopping: catchy jingles invading our heads with no intention of leaving.

Sometimes it happens unintentionally as you turn on the radio and tune in to a song. Other times, it catches you off guard. That it is so random can be frustrating — Why this song and why won’t it go away?

The phenomenon is commonly referred to as an "earworm" and it affects nearly 90 per cent of people once a week.

Despite attempts to "Let it go" like Elsa in Disney's Frozen, we're simply not able to "Shake it off" that easily (thanks Taylor Swift). However, while most of us groan as these pesky melodies echo in our heads, psychologists are trying to understand why this happens.

The auditory cortex on the left side of your brain is particularly sensitive to non-verbal information, such as song melodies. Although this area is activated when we hear a song, researchers have found that it is also stimulated when subjects are asked to imagine hearing a song or to fill in parts of songs that have been removed. This suggests earworms probably use a similar, if not the same, memory system.

While further research is still needed to understand how and why earworms function, one mechanism that could be involved is the "phonological loop", which is involved in the short-term memory of what we hear.

You can imagine the loop as a short recording tape that continuously stores small amounts of auditory information, such as a phone number. Information received is then either forgotten or moved into long-term memory.

Songs, in particular, seem to stick in short-term memory, looping for hours or even days in an extreme case. This may be due to the simple structure of songs that become earworms, which produce an abnormal response in the brain to give more attention to the song, leaving it to repeat within the phonological loop, like a broken record.

So, how can we scratch this cognitive itch? Some researchers say it's best to distract yourself with something involving language, such as starting a conversation. Perhaps giving attention to other verbal content will help push out the earworm from the phonological loop.

Unfortunately, the holiday season won't make it any easier, as we sing along (or cringe) to the Christmas earworms. You've been warned!

Catherine Lau is a graduate student in the Laurentian University – Science North graduate program in Science Communication. She’s had a serious earworm problem for as long as she can remember.