Many of us have experienced last song syndrome: We get in the car, turn on the radio, and hear the same top 40 songs on repeat every hour. Suddenly, we catch ourselves humming the melody of a song, and hear it play on a continuous loop in our heads. So, what makes some songs catchier than others?
Researchers at Durham University suggest some songs are more likely to stay with us based on their melodic content.
"These musically sticky songs seem to have quite a fast tempo along with a common melodic shape and unusual intervals or repetitions like we can hear in the opening riff of Smoke On The Water by Deep Purple or in the chorus of Bad Romance by Lady Gaga" said Dr. Kelly Jakubowski, lead author of the study from the Department of Music at Durham University, in a statement.
About 90 percent of us experience an earworm at least once a week, with some of us having them more than others, according to Jakubowski. It normally happens at times when the brain is not doing much, such as being in the shower, walking, or doing chores. 
In the study, published in Psychology of Aesthetics, Creativity and the Arts, researchers identified three distinct characteristics that make up an earworm: pace, shape of the melody, and a few unique intervals.
In terms of pace, earworms are faster and more upbeat in tempo and have rhythm people could move to. For example, previous research has found songs on a running or workout playlist tend to transport athletes into a state known as “flow,” which is when people are completely immersed in what they’re doing and feel as if they’re functioning on autopilot. Typically, a workout playlist will start with warmup and stretching music, and then transition to cardio songs, which gradually increase in intensity. The playlist migrates to strength-training tunes, and then concludes with mellow cool-down songs.
These songs are also more likely to be earworms, because of their gradual increase in intensity, followed by a decrease, and increase in between.
Science explains why you can't get that catchy song out of your head. Photo courtesy of Pexels, Public Domain
A song's melodic contour, or musical shape determines whether it's an earworm. These songs are simple in structure, but possess a rhythmic pattern. For example, the nursery rhyme "Twinkle, Twinkle, Little Star" rises in pitch, but it goes back down low and then rises again as a partner. This easy-to-remember melody makes a song an inevitable earworm.
A more recent example is Maroon 5's opening riff of “Moves Like Jagger,” one of the top-named earworm tunes in the study. It follows a common contour pattern of rising then falling in pitch.
Lastly, an earworm song possesses unusual interval structure, such as some unexpected leaps or more repeated notes than we would hear in the "average pop song." The instrumental riff of The Knack's “My Sharona” contains an unusual interval structure.
To obtain this data, the researchers used an online survey to ask 3,000 people for their most frequent earworm tunes. They compared them to tunes that had never been named as earworms in the database, but were a match in terms of popularity, and how often they were in the UK Music Charts. Melodic features of earworm and non-earworm tunes were analyzed and compared. The songs were limited to popular music genres, such as pop, rock, rap, rhythm & blues. (R&B).
The most frequently named earworms included:
Bad Romance - Lady Gaga
Can't Get You Out Of My Head - Kylie Minogue
Don't Stop Believing - Journey
Somebody That I Used To Know - Gotye
Moves Like Jagger - Maroon 5
California Gurls - Katy Perry
Bohemian Rhapsody - Queen
Alejandro - Lady Gaga
Poker Face - Lady Gaga
"We now also know that, regardless of the chart success of a song, there are certain features of the melody that make it more prone to getting stuck in people's heads like some sort of private musical screensaver,” said Jakubowski.
So, how do we get these earworms out of our heads?
A 2015 study in the Quarterly Journal of Experimental Psychology claims that chewing gum provides a simple solution. In a series of experiments, participants who were given gum to chew reported fewer earworms than those who weren’t. The researchers hypothesize since our vocal apparatus is involved in singing, when our jaws are otherwise engaged, our ability to imagine music is impaired.
At least we have a better understanding why we still can’t get Kylie Minogue’s 2002 hit song “Can’t Get You Out of My Head” out of our heads.
Source: Jakubowski et al. "Dissecting an earworm: Melodic features and song popularity predict involuntary musical imagery". Psychology of Aesthetics, Creativity and the Arts. 2016.

Top 20 most difficult songs to get out of your head revealed - and why they get stuck

Researchers have developed a mathematical formula to explain why some musical combinations are forgettable - and in some cases, inescapable

 

It's a frustrating thing most of us have experienced.
A song gets stuck inside of your head, seemingly playing on a permanent loop.
But what are the most difficult tunes to shift - and why do they get stuck in the first place?
Well, now you can find out - because researchers have developed a mathematical formula to explain the phenomena.
The experts claim the formula sheds light on why some musical combinations are unforgettable - and in some cases, inescapable.
These include Happy by Pharrell Williams , the Village People's YMCA and Queen's Bohemian Rhapsody and We are the Champions.
Scroll down for the top 20 earworms
Queen's Bohemian Rhapsody and We are the Champions were also deemed inescapable tunes

According to the research by the University of St Andrews, the recipe for an earworm has five key components.
These are receptiveness - how you feel about the song - predictability, surprise, melodic potency - how good the 'hook' is - and rhythmic repetition.
The exact formula was revealed as: Receptiveness + (predictability - surprise) + (melodic potency ) + (rhythmic repetition x 1.5) = earworm.
Bede Williams, of the University's School of Philosophical, Anthropological and Film Studies, looked at, among other things, a study into the nation's top 20 earworms, commissioned by Heinz to promote their new #cansong TV advert.
Bede, who is also research co-ordinator of the HARK project, which looks at our listening habits, said: "If you look at the songs which emerged from the research, they all have a distinctive rhythmic fingerprint - if we removed the melody they are recognisable by their rhythm alone.
"If you think of the opening of 'We will rock you' or the chorus of 'Who let the dogs out?' you'd be able to identify the rhythmic hook that persists throughout each song independent of the melody.
"Our sense of rhythm is fundamental to being human. We all experience the rhythm of our breath and hearts beating and from a very young age we are virtuosic rhythmic inventors as we turn babble into words and words into sentences.
Happy by Pharrell Williams was ranked as the second most difficult song to get out of your head
"A significant aspect of a successful earworm is also down to a catchy lyric, of which we will all remember for different reasons.
"Some of us may be attracted to meaning - 'is this the real life?', the sentiment in Pharrell's Happy, or simply the sound of the words such as Karma Chameleon.
"But embedded within all such chorus lyrics which are repeated throughout a song are often syllabic patterns that are known to be easily remembered.
"For example, the titles Jingle Bells, Shake it off and Gangnam Style would be referred to in poetry as anapaests, as they all have a pattern of two short syllables followed by a longer one.
"Uptown Funk is a perfect example of the rhythms of an earworm. One of the many devices used by the producers of Uptown Funk to make the song an earworm is the long rhythmic build-up of repeated phrases towards the drop of the chorus, which unusually, does not have any actual melody.
"It is basically all accompaniment and rhythm which we interpret in dance."
Bede, who studied as an ABRSM (Associated Board of the Royal Schools of Music) International Scholar at the Royal Conservatoire of Scotland, added: "Melodic potency and the 'hook' is an essential feature of an earworm.
"Melody and harmony work hand-in-hand and in earworms both are nearly always very simple, often using just a handful of notes and chords.
"Research has shown that when music strays from the predictable patterns of the regular scales and harmonies, it becomes harder to remember and less likely to become an earworm.
"It has also shown that much of our pleasure in listening to music comes from a delicate balance of the expected and unexpected.
"We like to have a sense of anticipation for what is coming next when we listen, but we don't like to be confused as to the overall trajectory of the song.
"That is why successful earworms contain so much rhythmic, harmonic and melodic repetition. Repetition allows our mind to create a synoptic, or over-arching view of the music.
Psy's Gangnam Style was also found to be a tricky tune to shift
"When we have such a memory of a song we can enjoy it in-the-moment with the comfort of knowing where it is going, which is a crucial part of the formula.
"And the hook of a song is often a carefully controlled section in which all of the musical elements lead our senses and are distilled into a potent mix which dances within our memory."
He added: "We know that we listen to music with our ears, but there is much we don't yet fully understand about the way that our bodies listen to and receive sound.
'Our body is made up of mainly water and bone, both of which resonate with sound waves.
"When we go to a live music event our body literally vibrates in sympathy to the music.
"Understanding how this embodied reception of sound contributes to the way music enters our memory is something that deserves a lot of attention in my opinion."
"A simple jingle about a product that is played during an advertising campaign will burrow into our minds as an earworm and through the power of music we will be able to more easily recall details of the product."
A spokesperson for Heinz Beanz said: "The study and formula have shown how important rhythm is to whether a song becomes an earworm or not.
"So it's no surprise that we believe our Heinz Beanz #cansong will become a huge hit with people.
"It has a melody and rhythm that people are drawn to and simply can't get it out of their heads.
"Perhaps that's why so many people want to learn the song and how to tap along with it!"

Top 20 earworms

We will rock you - Queen
Happy - Pharrell Williams
We are the Champions - Queen
I'm Gonna Be (500 miles) - Proclaimers
YMCA - Village People
Bohemian Rhapsody - Queen
Final Count Down - Europe
Living on a prayer - Bon Jovi
Jingle Bells
Who let the dogs out? - Baha Men
Gangnam Style - Psy
Never gonna give you up - Rick Astley
Don't stop believin' - Journey
Uptown funk - Bruno Mars and Mark Ronson
Shake it off - Taylor Swift
Beat it - Michael Jackson
Ruby - Kaiser Chiefs
The Time Warp - The Rocky Horror show
About the bass - Meghan Trainer
Karma Chameleon - Culture Club