The Ancient Origins of Your Musical Brain

"You know, if you happen to be standing next to a crocodile, your first thought probably isn't how similar you are to the crocodile" Recently I came across this new study that put a crocodile in a brain scanner and played it classical music.

And I was like... You did what now?

But it turns out that this weird intersection of crocodiles and technology can teach us something pretty cool about ourselves.

Like, when did we first develop the ability to perceive music?

[BrainCraft intro] Over the years, we've figured out how our human brains process sound, like tones and music.

For example, listen to this song.

As you hear it, you process sound in a hierarchical way - First you register the basic acoustic building blocks like frequency, harmonics, the duration and loudness of notes.

Next are the more complicated elements, like differentiating instruments and linking the sounds with stored memories.

And then the most complex, like your behavioural response to the sound.

And there's a relationship between brain structure and sound complexity - the more complex the sounds get, the more high-order brain areas activate.

But this isn't unique to our human brains - If I played this song to a bird, we'd see the same thing happening in their brain too.

You and a songbird process music in a really similar way - which is pretty remarkable considering on the tree of life, we branched off from each other hundreds of millions of years ago, and our brains evolved down two seperate paths.

But what if... the ability to process music developed before that?

What if it came from a common ancestor?

And this is where the crocodile comes in.

Crocodiles are the oldest surviving relatives of modern birds.

And ancient crocodiles look pretty similar to the ones we know today.

If we took a quick trip back in time, say 100 million years "There was sort of a form of crocodile that we would say, Oh that's some kind of a crocodile."

This is George Amato, the Director of Conservation Genomics for the American Museum of Natural History.

While they wouldn't look exactly the same as crocodiles do today, they would have "An elongated snout, lots of teeth, the ability to be hidden at the shore underwater, with most of your body underwater, just your nostrils and eyes up above."

Now crocodiles, birds and humans all shared a common ancestor around 300 million years ago "It's a very sort of generic looking, thick limbed reptile, that really then gave rise to mammals, archosaurs which are dinosaurs, and crocodilians and birds and then the other reptiles."

This means they're a killer example to study if certain traits in our brains have been conserved over time.

And in 2018, science has progressed far enough that we scan the brains of live reptiles.

I have been completely fascinated by your crocodile study you're involved in Researchers in Germany and South Africa worked together to study how crocodiles respond to sound - both tones and music.

Five young Nile Crocodiles were restrained, placed in an fMRI machine and exposed to different auditory stimuli: simple chord noises and then complex sounds, like Bach's Brandenburg Concerto No.

4, which has been used before in fMRI studies with birds.

The researchers found that simple tones activated their basic sensory areas, but complex sounds like music activated additional regions.

So crocodiles process sound and music in a hierarchical way - just like humans and birds.

It's been a preeetty long time since crocodiles, humans and birds branched off on the evolutionary tree.

So your brain's ability to process music out of simple tones and decipher complex sounds is something that likely emerged at least 300 million years ago.

Still, despite this commonality, you, an ancient giant crocodile and songbird probably have different tastes in music.