After soul, rock, and disco, rap is the biggest musical change of the past 50 years.
“Turn off that racket! That’s noise, not music. When I was young…”
At some point during our lives, most of us have heard our parents utter these words in desperation. And their parents are likely to have said something similar. And I’m sure some readers think or say the same to their kids.
After all, despite revivals and recurrent themes, music changes. Like a population of organisms, it evolves. If that’s the case, then why not apply methods used in evolutionary biology to learn more about the evolution of music?
Thanks to the listeners
Researchers from Queen Mary University in London did just that and dug into the American pop charts of the last five decades, unearthing over 17 000 songs to learn more about the evolution of music.
To classify all those songs, they developed a system that included eight harmonic topics (which are a way to capture cord changes) and eight timbral topics that capture changes in timbre (think about vocals, percussion, and so on).
With the help of tags assigned by Last.fm listeners, the authors could interpret topic changes over the years. Some of the things they found were the decline of seventh chords when blues and jazz lost prominence in the top 100 and the decline of drum machines since the ‘90s. The greatest change, however, was the fairly sudden rise of songs that lack a clearly identifiable chord structure since the ‘80s, accompanying the rise of Hip Hop in the charts. Another change following this trend was the increase of ‘energetic speech’ in popular music.
Evolution, revolution and diversity
The researchers also looked at the speed of these changes. Did they occur gradually or sudden? While music changes continuously, they identified three periods of rapid change: the smallest one in 1964, the rise of soul and rock, a slightly larger one in 1983 when new wave, disco and hard rock entered the stage. The big kahuna, however, burst onto the scene in 1991. Rap music was the main culprit for this revolution.
Also, while some bemoan the loss of diversity in modern music (“It all sounds the same, this modern stuff”), there was no evidence to back this complaint. True, the use of some harmonic and timbral topics decreases, but others gain popularity. Overall, music is as diverse as it ever was, just different.
A critical note
Is everything said about the evolution of music, then? Not at all, and the authors are well aware of this. Sixteen topics is a good number, but songs are much more complex. Other measurements might give other results. Also, using the US Top 100 of the last fifty years hardly captures all of music (and even within the genres mentioned, several sub-genres almost never appear in the pop charts). Finally, while they describe the changes in styles of popular music, the reasons for these are not uncovered.
Nevertheless, this study is a really cool example of how culture evolves much like the biological world and how we can use methods from one field of science to learn neat things in another one.
Rap (or rock) on.
Mauch, M., MacCallum, R., Levy, M., & Leroi, A. (2015). The evolution of popular music: USA 1960-2010 Royal Society Open Science, 2 (5), 150081-150081 DOI: 10.1098/rsos.150081