Some music genres are getting simpler, new research shows

Jazz and Western classical music are now more like pop and rock — at least by one measure. The melodic and harmonic structures of jazz and classical have become simpler over time, according to a mathematical analysis in the April 23 Scientific Reports. 

“We are observing an evolution in music,” says Niccolò Di Marco, a computational social scientist at the University of Tuscia in Viterbo, Italy. That shift may be fueled by digital technologies, which make access to and inspiration from recorded music easier.

Di Marco and colleagues analyzed 21,480 musical pieces across six genres of Western music — classical, electronic, hip hop, jazz, pop and rock. The team used an audio file format, called MIDI, that encodes information such as notes played, their timing, duration and loudness in numeric values. From this, they extracted data about melodies and harmonies in the music, and used it to map the relationship between notes, such the order in which notes were played and which notes followed which. These networks allowed the team to then visualize and analyze patterns.

On the whole, the distribution of this data was more uniform in newer musical genres, such as pop, electronic and rock. Older genres like jazz and classical music had more varied patterns. But when the researchers traced these trends over time, they noticed something interesting.

The first half of the 20th century boasted quite complex structures in jazz and classical music. In later decades, there is a trend toward a repetitiveness of harmonies, intervals and other structural features, more like the patterns shown by genres such as pop and rock. This, Di Marco says, “is a measure of the how that piece explores the possible musical space … following the rules of music.”

Having new technologies like digital audio and composition tools for musicians at everyone’s fingertips has changed how modern musicians make music, Di Marco says. He has also studied trends in album cover art, finding a “broad shift towards minimalism.”

This doesn’t mean jazz or classical music is getting bland or losing quality. The paper is about the mathematical framework of music and not about the sound or the listening experience, Di Marco and colleagues say. There is so much more that goes into making music, such as lyrics, production, sound design and cultural context. Modern music creators are simply finding “a different way to create great music,” Di Marco says. Like the album covers, this art form too is shaping and being shaped by cultural and technological evolution.

Cultural musicologist Friedlind Riedel agrees. By looking at only certain aspects, it could come across like there has been a loss of musical diversity, says Riedel, of the University of Salzburg in Austria. 

“There has always been an anxiety about simplification in music” she says. “As in all arts, there is a long history of cultural pessimism, the idea of a cultural gray-out…. However, musical listening opportunities have probably never been more diverse in history than they are today.”