​London, Nov 4 (IANS) British scientists have identified the reason behind what makes a song so catchy that it gets stuck in our head and goes on playing in an endless loop -- known as experiencing involuntary musical imagery or earworms.

Findings of a study, published in the journal Psychology of Aesthetics, Creativity and the Arts, showed that songs that are usually faster and have a fairly generic and easy-to-remember melody but have some unique intervals such as leaps or repetitions that set them apart from the "average pop song" get stuck in our head.

"Our findings show that you can, to some extent, predict which songs are going to get stuck in people's heads based on the song's melodic content," said lead author Kelly Jakubowski from Durham University in Britain.

In addition to a common melodic shape, the other crucial ingredient in the earworm formula is an unusual interval structure in the song such as some unexpected leaps or more repeated notes than you would expect to hear in the "average pop song". 

"The study could help aspiring song-writers or advertisers write a jingle that everyone will remember for days or months afterwards," Jakubowski added.

In the study, the team asked 3,000 people for their most frequent earworm tunes and compared these to tunes which had never been named as earworms in the database but were a match in terms of popularity and how recently they had been in Britain's music charts.

The melodic features of the earworm and non-earworm tunes were then analysed and compared. Songs were limited to popular music genres, such as pop, rock, rap, rhythm and blues.