“Won’t you play a simple melody,” sang Bing Crosby in his rendition of the Irving Berlin classic. Now it seems his wish has come true: research has revealed the tunes of modern chart-toppers are less complex than those of the past. Scientists say the change could – at least in part – be down to the emergence of new genres over the decades, such as stadium rock, disco and hip-hop. However, Madeline Hamilton, a co-author of the research from Queen Mary University of London, said the results did not mean music was dumbing down. “My guess is that other aspects of music are getting more complex and melodies are getting simpler as a way to compensate,” Hamilton said, noting that while music in earlier decades was made with a handful of instruments – meaning complexity tended to be added through vocals – modern tracks involved many layers and sound textures. Writing in the journal Scientific Reports, Hamilton and her co-author Dr Marcus Pearce describe how they studied songs placed in the top five of the US Billboard year-end singles music chart each year between 1950 and 2022. These included Heartbreak Hotel by Elvis Presley, Hey Jude by the Beatles, Vogue by Madonna, Poker Face by Lady Gaga and Irreplaceable by Beyoncé. They then analysed eight features relating to the pitch and rhythmic structure of the melodies. The results revealed the average complexity of melodies had fallen over time, with two big drops in 1975 and 2000, as well as a smaller drop in 1996. Hamilton said one explanation was the rise of different genres of music, with the first drop occurring around the time stadium rock and disco music became popular. “The [drop] around the year 2000 [is] probably at least partially due to the rise of hip-hop, because those melodies are very distinct. They’re very simple melodies, normally,” said Hamilton. The smaller decline around 1996, she added, could also be linked to hip-hop, although another possible influence is the rise of the digital audio workstation, which makes it easy to loop sections and phrases within songs. “We’re thinking that could be leading to an increase in repetition in the melodies,” she said. But changes to melodies do not necessarily reflect the full picture. The analysis revealed chart-toppers had shown an increase in the density of notes – in other words the number of notes being sung per second – particularly since the year 2000. “If you have a melody [with a] lot of notes per second, that kind of limits how complex [the melody] can be,” said Hamilton. “Whereas if you’re singing slower, you can sing more unexpected pitches, or you can do bigger jumps and stuff.” The team said other studies had found no sign of a decline in the timbre or harmony of music over the 50 years since 1960. And while “revolutions” in popular music had previously been identified, their timing differs – something Hamilton and colleagues say could be down to other work focusing on different features of music, and the fact that the new study only looks at chart-toppers. Hamilton said she was expanding her analysis to include other aspects of music: “Right now, we’re looking at chords. We also want to expand our analysis to include more songs, to see if this trend [for melodies] holds up for a bigger set of music.”