How Music Has Evolved in the Past 70 YearsExpand
Humankind has had music for as far back as we're able to define ourselves as such. Some of that music has always been favored by the other cave people, hunters-and-gatherers, farmers, shamans, and whoever else was hanging around.
As society changes, our favorite music changes too, and variations in musical memes are passed down through the years.
To examine these changes in popular music, The Echo Nest data alchemist Glenn McDonaldtraced nine distinct audio attributes in the 5,000 hotttest songs from each year, 1950 to 2013. This demonstrates the ability of The Echo Nest's deep musical understanding to scale across decades, regions, genres, and more, but it's also just neat from a sociological/musical perspective.
Seven of those ways showed detectable changes in music from 1950 to the present day:
The Echo Nest sees music from many angles — everything from reviews written by critics and fans, to the audio attributes of the music itself, which we get by literally listening to the music with software. Our "energy" attribute is part of that later approach. As the name suggests, it measures the energy level of a song. If, for example, a customer of ours were to build a jogging playlist or standalone application, this attribute would be of particular interest to them… but what interests us here is that after a brief plateau, pop music has roughly grown more energetic since the dawn of rock 'n roll.
How Music Has Evolved in the Past 70 Years

Music today is more "mechanized" than in the past. It's not that music is literally made in a factory now, but more that musicians have increasingly had access to metronomes, clicktracks, drum machines, arpeggiators, electronic keyboards, sequencers, sophisticated software, and other things that tend to produce less than "organic" sound.
The result: The Echo Nest detects decreasing organicness from 1950 to 2013:
How Music Has Evolved in the Past 70 Years

As time marches on, its beat has grown increasingly consistent, due to drum machines, click tracks and the like. Back when all drummers walked the earth as humans, the tempo used to drift a bit more, within songs. Today, we have some songs where every note is exactly quantized and locked onto the tempo, although much of what we listen to these days consists of a combination of organic and mechanistic sounds.
How Music Has Evolved in the Past 70 Years

Boing Boing! That's not just the sound of Boing Boing founder and editor Mark Fraunfelder calling Glenn McDonald's Every Noise At Once one of his two favorite things on National Public Radio — it's also the sound of music being bouncy.
Our bounciness attribute sees stuff like tech house and reggae as extremely bouncy, while atmospheric black metal and choral music exhibit a more fluid sound. As you can see, popular music has grown less bouncy since the '50s, meaning that we prefer things a bit smoother these days:
How Music Has Evolved in the Past 70 Years

It doesn't take an ethnomusicologist to see that popular music has grown less acoustic over time. Everyone from Bob Dylan to St. Vincent prefers the electric guitar, and that's just one instrument that electronification has spawned. Some other instruments couldn't exist without electricity, others without electronics. The overall result is that music has grown less acoustic sounding, as reflected by our acousticness attribute:
How Music Has Evolved in the Past 70 Years

Glenn's research into how loud music has gotten really struck a chord, with follow-up reports from FastCompany, Gizmodo, and Tonedeaf. It's true — music really has grown louder sounding over time, as part of the so-called "loudness wars." That is 100-percent backed up by our loudness attribute, although audio volume is a bit complicated, so if you really want to understand the science here, you should read this.
How Music Has Evolved in the Past 70 Years

Cars are faster now. Information is faster. And so, too, is our favorite music.
By looking at the 5,000 hotttest songs from each year, McDonald found some interesting trends. We liked our music fastest during the "'go-go" '80s, then music grew slower again in the mid-90s, and now it's back to being just about as fast as ever:
How Music Has Evolved in the Past 70 Years

This post was originally published on The Echo Nest's blog. Follow The Echo Nest on Twitter or Facebook for more unique research into music.