Babies got beat: Why rhythm might be innate

Rhythm is everywhere. Even if you don’t think you have it, it’s fundamental to humans’ biological systems. Our heartbeat is rhythmic. Speech is rhythmic. Even as babies, humans can track basic rhythm. Researchers wanted to find out if there were more layers to this: Could babies also track melody and more complicated rhythms? So they played Bach for a bunch of sleeping newborns and monitored the babies’ brains to see if they could predict the next note. What they found offers clues about whether melody and rhythm are hard-wired in the human brain or learned over time. We also get into what powers the eating habits of some snakes and chameleons, and insights into the role of sleep in problem-solving. Have a scientific question you want us to answer? Email us at [email protected] mailto:[email protected]. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave http://plus.npr.org/shortwave. Listen to Short Wave on Spotify https://n.pr/3HOQKeK and Apple Podcasts https://n.pr/3WA9vqh. This episode was produced by Jordan-Marie Smith and Rachel Carlson. It was edited by Rebecca Ramirez and Christopher Intagliata. Tyler Jones checked the facts. The audio engineers were Jimmy Keeley and Hannah Gluvna. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

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• 0:18Speaker 01

  You're listening to Short Wave from NPR.

• 0:24Regina Barber?

  Hey, Short Wavers. Regina Barber here.

• 0:26Speaker 03

  And Rachel Carlson.

• 0:27Regina Barber?

  And today we have our biweekly Science News roundup, featuring the hosts of All Things Considered. And today we have one of my favorite gamers, Juana Summers.

• 0:36Speaker 01

  Hello. Excited to be here. So I heard, y'all, that we are talking about babies listening to Bach to see if they can perceive rhythm and melody just after birth?

• 0:44Speaker 03

  Yep. Plus, a finding that could tell us more about why reptiles feed on very different timescales compared to humans.

• 0:50Regina Barber?

  And the old adage, sleep on it, may actually help you solve a problem.

• 0:57Speaker 03

  All that on this episode of Short Wave, the science podcast from NPR.

• 1:08Speaker 00

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• 1:50Speaker 00

  learning. The app guides users to intuitively think in a second language using images and contextual

• 1:56Speaker 01

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• 2:14Speaker 00

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• 2:33Speaker 03

  OK, Wana, where do you want us to start?

• 2:35Speaker 01

  OK, I want to start off with music and babies, Rachel.

• 2:38Speaker 03

  Yeah, OK, so scientists know that even as babies, we can track basic rhythm like this. But they didn't know how primed our youngest minds were to perceive melody or more complicated rhythms like this.

• 2:53Speaker 03

  All the way to complicated drum solos.

• 2:55Speaker 01

  Interesting, OK, so how did scientists test this?

• 2:58Regina Barber?

  In a study out this week in PLOS Biology, scientists played piano music by Bach to sleepy newborn babies. And the babies were hooked up to these EEG machines to see how well their little brains predicted rhythm or the melody.

• 3:12Speaker 01

  Love this, so what did they find?

• 3:15Speaker 03

  They were looking for brain signals that show the babies were predicting the next note. In adults, our brains predict both the rhythm and the melody of the next note. But they found that the babies tracked the rhythm, even though it could get pretty complicated.

• 3:27Speaker 01

  But the babies didn't track the melody?

• 3:29Speaker 03

  Interesting, so does that mean that babies have rhythm at birth but not melody?

• 3:34Speaker 01

  Seemingly, possibly. Hmm, and do they have an idea as to why we might have this sort of innate sense of rhythm really early in life?

• 3:41Speaker 03

  Yeah, we also talked to Laurel Trainor about that. She's a developmental neuroscientist at McMaster University. She studies music perception. And she said it's likely because rhythm is everywhere.

• 3:52Speaker 04

  Babies crawl rhythmically, they flail their arms rhythmically, their heartbeats are rhythmic. So in biological systems, rhythms are just fundamental to everything, from movement to proceeding, things like speech. Music to thinking.

• 4:07Speaker 03

  So she says it makes sense that predicting rhythm is an ancient trait. After all, she points out, the babies are exposed to rhythm in the womb through the mother's heartbeat and walking.

• 4:16Regina Barber?

  But melody, on the other hand, isn't present at birth, at least not in the part of the brain where the scientists were looking. But just because the scientists didn't see it doesn't mean it's not there. And we should note that the study only looked at Western classical music.

• 4:30Speaker 01

  Interesting. Okay, let's go to our next topic. And there's a clue about snakes and hunger, I understand. I am not the biggest fan of snakes, but I'm willing to go on this journey with you.

• 4:39Speaker 03

  Snakes freak me out, but they are extraordinary when it comes to their feeding patterns. Some can go without food for months or even a year.

• 4:47Speaker 01

  Right, and then they'll eat a huge meal, right?

• 4:48Speaker 03

  Yeah, exactly. My brother honestly does this, so I call it his snake meal. But researchers haven't understood if there's a genetic piece to why snakes and some other reptiles do this, but now they might have a clue. Researchers looked at the genomes of over 100 reptile species and found some snakes and chameleons have lost the genes that produce the hunger hormone ghrelin.

• 5:09Speaker 01

  And humans have that too, right? That's why I'm hungry right now.

• 5:12Regina Barber?

  Yeah, we do. It's all part of this hormonal system of appetite in humans. As ghrelin levels rise in our bodies, we get hungry. I just satisfied mine. I just had a sandwich. It's also involved in how much we eat and body weight regulation. And you've probably heard of another appetite hormone, GLP-1.

• 5:31Speaker 01

  Right.

• 5:32Regina Barber?

  Yeah, it's sort of like ghrelin's counterpart. It tells us when we're full.

• 5:35Speaker 01

  So what does this mean for snakes if they don't produce this hunger hormone?

• 5:39Speaker 03

  The researchers think this finding could tell us more about why snakes are able to fast for months. And the study was published this week by the Royal Society. I talked to another evolutionary biologist who wasn't involved in this study. His name's Alex Pyron, and he told me studying these kinds of metabolic pathways in reptiles could tell us more about humans in the future with more research.

• 5:59Regina Barber?

  Bonus trivia, Juana, did you know that GLP-1 drugs like Ozempic were inspired in part by research on Gila monster venom?

• 6:07Speaker 01

  I did not know that.

• 6:08Regina Barber?

  Yeah, it's super cool. So sometimes animal studies can have surprising payoffs.

• 6:12Speaker 01

  All right, let's move on to our third topic. And this one I'm excited about because I love sleep and I have a lot of problems that need solving, and I hear that sleep might help.

• 6:21Regina Barber?

  Yeah, I mean, when I was in college, I would dream about difficult quantum mechanics problems, and it turns out it might have helped me.

• 6:28Speaker 05

  We learn during the day very effectively, but to really make it stick, we need something additional, and some of that's happening during sleep.

• 6:35Speaker 03

  That's Ken Paller, a cognitive neuroscientist at Northwestern University, and he and his team studied this by working with 20 lucid dreamers, so people who are sometimes aware that they're dreaming, which I'm very jealous of.

• 6:46Regina Barber?

  Mm-hmm.

• 6:47Speaker 03

  And they asked them to solve brain teaser puzzles or riddles. Like, here's one of them, Wana, can you find a meaning or a cute way to interpret this set of letters? G-E-S-G.

• 7:00Regina Barber?

  I literally have no ideas. Please help me.

• 7:03Speaker 03

  We're gonna let that one simmer.

• 7:05Regina Barber?

  We'll marinate.

• 7:05Speaker 03

  Think about it for a while, yeah. And in the meantime, I'll tell you more about the study. So the scientists only gave the volunteers three minutes to solve puzzles like this, which usually wasn't enough time. And then they also played a unique soundtrack while people were solving each puzzle.

• 7:20Regina Barber?

  And Wana, as you stare at these letters like G-E-S-G in confusion, imagine like also hearing the song.

• 7:30Regina Barber?

  The idea was to help people's brain like link the puzzle to a sound or a song, and then the participants were told to go to sleep.

• 7:37Speaker 01

  Huh, and then what happened when they went to sleep?

• 7:39Speaker 03

  So the scientists monitored the sleepers, and once they entered REM sleep, the researchers would play that unique soundtrack cue to do a little inception. They wanted to encourage dreaming about that specific puzzle that they hadn't been able to solve when they were awake.

• 7:53Speaker 01

  So what did they find? Can you solve puzzles in your sleep like Gina?

• 7:55Speaker 03

  Well, after the volunteers woke up, they were more than twice as likely to solve puzzles they dreamt about compared to puzzles they didn't remember dreaming about. So, yeah, the results are published in the journal Neuroscience of Consciousness.

• 8:08Regina Barber?

  Speaking of which, Wana, did you have an answer for a riddle from earlier, like looking at these letters G-E-S-G?

• 8:15Speaker 01

  No, I didn't have time to sleep on it, and I'm just really bad at these.

• 8:19Speaker 03

  Do you want the answer?

• 8:20Regina Barber?

  I am too.

• 8:20Speaker 01

  I do.

• 8:21Speaker 03

  OK, the answer is scrambled eggs.

• 8:24Speaker 01

  Well, now I'm just hungry again. How do you get scrambled eggs out of G E S G?

• 8:28Regina Barber?

  Because it spells eggs.

• 8:29Speaker 03

  It spells eggs, but they're mixed up. I didn't get it either, honestly.

• 8:33Regina Barber?

  But the bigger point isn't the answer to this one puzzle that stumped all of us. It's that the scientists are one step closer to answering that age old question, like, why do we dream? Like, what is it for? And according to Robert Stickgold, another dream researcher that didn't work on the study, dreams aren't just entertainment. They're a catalyst for processing information and inducing creativity.

• 8:53Speaker 01

  Very interesting. You've given me something to think about when I doze off later tonight.

• 8:57Regina Barber?

  Yeah, hopefully it's not work.

• 8:58Speaker 01

  Hopefully not.

• 8:59Regina Barber?

  Wanda, thank you so much for coming on our show and having so much fun with us solving puzzles.

• 9:03Speaker 03

  Yeah, next time we'll have more puzzles.

• 9:05Speaker 01

  Oh, no, I'm still not going to be good at them, but I will bring my best game.

• 9:12Regina Barber?

  You can hear more of Wanda on Consider This, NPR's afternoon podcast about what the news means for you.

• 9:18Speaker 03

  And for more science stories just like this one, follow Short Wave on whatever app you're listening to. I produced this episode alongside Jordan Marie Smith and Burleigh McCoy. It was edited by Christopher Intagliata and Rebecca Ramirez.

• 9:31Regina Barber?

  Hannah Glavna and Jimmy Keely were the audio engineers. I'm Regina Barber.

• 9:36Speaker 03

  And I'm Rachel Carlson. Thanks for listening to Short Wave, the science podcast from NPR.

• 9:59Speaker 06

  Stay tuned for the following announcements and messages from our sponsors.