- Researchers claim the secret to a smash hit single is repeating the lyrics
- They found songs that repeat phrases are more likely to be successful
- Hit singles repeated words up to a fifth more than music lower in the charts
Some musicians spend an entire career trying to dream up a beautiful melody or an unforgettable riff.
But the secret to a hit single, it seems, is simple.
Repetition is the key, according to psychologists who analysed five decades of chart-toppers.
They found that songs which repeated entire phrases and individual words more often were likely to be commercially successful.
Hit examples identified by the team include Madonna's 1986 song Papa Don't Preach, and Taylor Swift's Shake It Off
Regardless of the tune, the tempo, or how attractive the musician was, the researchers found that number-one singles repeated the same words up to a fifth more than music lower down in the chart.
Study author Joseph Nunes and his team analysed 55 years of the US Billboard's Hot 100 singles chart.
They looked at the lyrics of more than 1,000 songs which reached number one in the chart between 1958 and 2012.
They compared them to 1,450 singles which made it onto the chart - but never climbed above the 90th ranking.
Professor Nunes, of the University of Southern California, said: 'To make it into the Hot 100 more repetitive songs do better.
'We expect songs that are lyrically more repetitive, for instance by repeating the chorus more often, and thus more fluent, to be generally preferred and adopted more quickly and broadly in the marketplace.
'Repeated lyrical phrases are often accompanied by the same melody and rhythm.'
Musician Taylor Swift poses with her awards at the Billboard Music Awards in 2013
The researchers suggested that repeating a phrase makes it easier to understand quickly, requiring little input from the listener.
And the easier it is to process, the more pleasurable an experience it creates.
'Fluency is characterized by processing being faster, more accurate, and requiring fewer cognitive resources,' they wrote.
'The pervasive presence of music in people's lives is indicative of the pleasure it provides.'
Professor Nunes said: 'The chorus of a song is often used as a 'hook' to catch the ear of the listener and is repeated regularly throughout a song.
'One benefit derived from having encountered a stimulus previously, or repetitive priming, is an ease of processing.
'An ancillary benefit resulting from processing fluency, notably for aesthetic goods, is that the experience is typically more pleasant.'
The study, published in the Journal of Consumer Psychology, found that more successful songs also tended to be slightly longer.
Professor Nunes, once a bass guitarist in a teenage band, added: 'We were trying to figure out what separated the most popular songs from less popular songs.
'Unfortunately we have not uncovered the formula for a future hit yet, otherwise I would be a producer, not an academic.
'But we can describe what succeeded in the past, however we can't necessarily predict it will succeed in the future.'
His team concluded that the secret to the hit single might help marketers and advertisers.
They wrote: 'We believe these results have important implications for consumer research involving information goods and diffusion as they suggest fluency helps accelerate adoption.
'It would be reasonable to expect repetitive messages to spread faster, as they would be expected to be easier to process and therefore more fluent.
'These results may also have strategic implications for marketers, especially when it comes to advertising text and product jingles.'