The idea that contemporary music doesn’t measure up to its predecessors is probably as old as music itself. Music critics bashed jazz when it first appeared in the early 20th century, and then rock’n’roll, punk, heavy metal, hip-hop, 2000s pop, and so on. With this in mind, whether today’s music is better or worse than before is a deeply subjective opinion — but that doesn’t mean it’s not different.

A new study from Queen Mary University of London seems to confirm what many of us have been suspecting all along: melodies in modern chart-topping songs are less complex than those of previous decades. The researchers believe that the shift in melody complexity might be attributed to the advent of new music genres like stadium rock, disco, and hip-hop.

However, this doesn’t mean that modern music is necessarily less complex overall. Earlier popular music was typically released by bands with a handful of instruments that relied on vocals to add harmonic complexity, whereas today’s music is more studio-heavy and polished through many subtle layers and textures.

The researchers analyzed the top five hits on the US Billboard year-end singles chart from 1950 to 2022, such as Heartbreak Hotel by Elvis Presley, Hey Jude by the Beatles, Vogue by Madonna, Poker Face by Lady Gaga, and Irreplaceable by Beyoncé. They used software that analyzed each song for features relating to pitch and rhythm.

The results published in the journal Scientific Reports suggest an overall trend of declining melodic complexity, with two major drops recorded in 1975 and 2000, as well as a smaller one in 1996. The first major drop is attributed to the advent of stadium rock and disco music, while the 2000 drop can be explained by the rising popularity of hip-hop music, which is known to heavily rely on looped samples. The mid-1990s drop can also be pinned down to hip-hop, although the researchers also point out that it was around that time that digital audio workstations (DAWs) became popular. DAWs allow music producers to edit tracks and recordings on a computer; as computers become more prevalent, so did the number of ‘bedroom’ producers, some of whom would go on to become professionals.

However, the study points out that this simplification of melodies does not tell the whole story. The analysis also showed an increase in the density of notes, or the number of notes sung per second, especially since 2000. This increase in note density can limit the complexity of melodies. If you have a melody with a lot of notes per second, that kind of limits how complex the melody can be because there’s less room for other musical tones.

Interestingly, other studies have found no decline in the timbre or harmony of music over the last 50 years. This could be down to other work focusing on different features of music, and the fact that the new study only looks at chart-toppers. In fact, it does seem the case that the most popular music is less complex overall, as one 2014 study found:

“We find empirical evidence that individual styles show dramatic changes in their instrumentational complexity over the last fifty years. ‘New wave’ or ‘disco’ quickly climbed towards higher complexity in the 70s and fell back to low complexity levels shortly afterward, whereas styles like ‘folk rock’ remained at constant high instrumentational complexity levels.”

“We show that changes in the instrumentational complexity of a style are related to its number of sales and to the number of artists contributing to that style. As a style attracts a growing number of artists, its instrumentational variety usually increases. At the same time the instrumentational uniformity of a style decreases, i.e. a unique stylistic and increasingly complex expression pattern emerges. In contrast, album sales of a given style typically increase with decreasing instrumentational complexity. This can be interpreted as music becoming increasingly formulaic in terms of instrumentation once commercial or mainstream success sets in.”

Another similar study by the Spanish National Research Council used AI to examine nearly half a million pop songs released between 1955 and 2010. The study concluded that pop music has become melodically less complex, using fewer chord changes, and that pop recordings are mastered to sound consistently louder (and therefore less dynamic) at a rate of around one decibel every eight years.