You may have a love or an abrupt dislike for pop princess Britney Spears, but you cannot deny her debut single Baby One More Time has become stuck in your brain at some point - and a psychology expert knows why.
During the day Tim Byron lectures at the University of Wollongong, in NSW's Illawarra region, but by night he plays keyboard for various different bands - his love for both has left him wondering what makes the ultimate pop song.

Dr Byron has co-written a new book explaining just that with Jadey O'Regan from the Sydney Conservatorium of Music, and uses Britney's 1998 chart-topper as a stellar example.
"That song has lots of hooks, in fact, I think that is actually the song that is mentioned the most in our book [Hooks in Popular Music]," he told ACM.
He said the book defines a hook as a musical moment or musical phrase that stands out and is easily remembered. These are the bits of songs that are more likely to end up as "ear-worms", the elements of the songs that become stuck in our head.

In the case of Baby One More Time, it was written by Swedish producer Max Martin who is responsible for many number one hits over decades including for Taylor Swift (Shake It Off), Katy Perry (I Kissed A Girl) and Pink (Who Knew).
Ear-worms are something Dr Byron is still researching but the catchier the hook, the more times you hear it and when you heard it all play a factor in a song getting stuck in your head.
But does the new book hold the secret formula all musicians need to know if they want their own songs to become ear-worms? Perhaps, yes.
"The big, dumb pop songs that everyone knows aren't really that dumb because they are very, very carefully crafted and put together," Dr Byron said.
Other examples of pop hits with hooks which could easily get stuck in your head include Kylie Minogue's 2001 hit Can't Get You Out Of My Head, Third Eye Blind's 1997 song Semi Charmed Life and Can't Feel My Face by The Weekend.
If you've ever gotten a Wiggles song stuck in your head, that is no accident either, according to Dr Byron.
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He explained some of the original members of the band had been studying child psychology and early learning so knew the basics to get the attention of toddlers and their mums and dads.
"The Wiggles know what they're doing," he said.
"It comes down to a song getting stuck in your head and it comes down to something that's going to be memorable. So for us a 'hook' is a song that you know that gets your attention and that you remember ... those bits that stand out.
"So I think The Wiggles are pretty good at coming up with those bits that will stand out both to to the kids and the parents."

Hooks in Popular Music is a comprehensive book with 459 pages explaining the importance of what makes a song catchy, and as Alanis Morissette memorably said in 1995, it's the kind of stuff You Oughta Know.
"If a bit of a song is getting our attention, if there is a bit of a song that we're remembering, then it's doing something right and it's almost exploiting the specifics of how our memory and attention works," added Dr O'Regan