Short Wave - What Chimpanzee Gestures Reveal About Human Communication

Episode Date: July 26, 2024

Chimpanzees are humans' closest living relatives. But does much of their communication resembles ours? According to a new study published earlier this week in the journal Current Biology, chimpanzees gesture back-and-forth in a similar way to how humans take turns speaking. The research presents an intriguing possibility that this style of communication may have evolved before humans split off from great apes, and tells researchers more about how turn-taking evolved. Interested in more science news? Email us at [e-mail] to Short Wave on Spotify and Apple Podcasts.See 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

You're listening to Shortwave from NPR. Hey, Short Waver, is Regina Barber here. And this time our news roundup buddy is the one and the only, Elsa Chang. Woo! Just shark, cheering for myself over here. We're so excited for you to come and play with us. We love having you on. It's been a long time.

I love playtime with you guys. And we have our fabulous co-host extraordinaire, Emily Kwong. Oh, thank you. Hi, Gina. Okay, as you both know, we're going to share three science stories in the news that have caught attention recently. Yeah, yeah, yeah. And I want to say the first one, we have got chimpanzee gestures revealing things about communication. How oxygen is created at the bottom of the ocean. Yeah, and how a computer program may warn people before a huge rogue wave hits. All of that on this episode of Shortwave,

the science podcast from NPR. All right, Elsa, you're our guest. We want to make you feel welcome, you know, happy. Which topic do you want to start with first? Well, of course I want to start with gesticulating chimpanzees. Right. Let me ask, do they use their hands as much as I do to communicate? Okay, yeah, chimps definitely do. I mean, they don't have full-blown language like we do. So gestures are really important for communication. Can I show you a clip of that? Please.

Okay, so these are two chimpanzees in a tree. They just had some conflict. And you can see that one chimps reach just for the other chimps hand, like, I'm sorry. And after a pause, the other chimp gently taps their hand back. It looks so tender. I'm watching this. Like, they're really making up. Is that happening?

Yeah, I mean, maybe. So, like, gestural exchanges like this are the topic of a recent paper in the journal, Current Biology. Gal Badehi is a postdoctoral research fellow at the University of St. Andrews in Scotland and the lead author of this paper. And my part was the East African chimpanzees. Sweeping an enormous data set, Gall looked at exchanges, among five wild chimpanzee populations.

Usually these exchanges had like two parts, hand reach, hand tap back, but sometimes these exchanges had up to seven parts, which was super exciting to see. Because they seem to have this back and forth in a face-to-face communicative setup that kind of resembles human conversations a little bit more. That's so cool.

And they're sure that it has nothing to do with the sounds that they're uttering towards each other. It's just the gestures. Well, they are making sounds, but the gestures is what they were really paying attention to because of the pacing of the gestures. Like the back and forth was really similar to human conversation. The pause between a gesture and a gestural response averaged to about 120 milliseconds. Wow.

Wow. Okay. Well, how close is that to human response? Yeah, conversational turns in humans average to about 200 milliseconds across language. No way. Again, all very rapid fire, all very fast. I had no idea there was a rate. Anyway, if chimps are supposed to be like one of our closest living relatives,

right? Like, does this reveal anything about the evolution of how humans communicate? It presents an intriguing possibility, yeah, that this kind of back-and-forth communication may have evolved before humans split off from great apes. We don't know for sure. But several primatologists I spoke to who were not a part of the study all felt this was an important contribution to understanding how turn-taking and communication dynamics evolved. No language required. That is so fascinating. Okay, Now we're going to take a sharp turn and move to oxygen on the seafloor. I take it that that is a weird thing, right? Otherwise, we would not be talking about it.

Yeah. So most of our oxygen is created through photosynthesis. That's when plants take in light, water, and carbon dioxide. And then they make, like, sugar and oxygen. But for over a decade, scientists were aware of traces of oxygen at the bottom of the ocean, like three miles down where there's no light, no photosynthesis. So where did this oxygen come from? And a new study in the journal, Nature Geoscience may have an answer. It shows that oxygen produced without light, called dark oxygen,

could be coming from bits of metal in the deep ocean. Wait, metal? What kind of metal is in the deep sea? Like, how did it get all the way down there? It's these clumps of metals like nickel, manganese, cobalt, iron that form these nodules on the seafloor. And they grow on top of stuff that falls to the bottom, like sharp. Yeah, I talked to physical chemist Franz Geiger about this, and he's one of the papers co-authors, and he studied these clumps of metal in the lab. He specified it's not a rock, and these nodules grow one millimeter per million years.

And these are a few centimeters big, so these clumps of metal accumulated over millions and millions of years. Whoa. Think of like a really, really slow game of Tetris. Okay. So these clumps of metal grow very, very slow. They glom together. And how are they producing oxygen? Like, I thought that is what plants do. Right.

So preliminary experiment suggests it's partly through electrolysis of seawater. So electric current in the middle chunks splits ocean water H2O into hydrogen and oxygen. But the sensors, they used, only detect oxygen. So they need more data before they can be like, sure, this is happening. That's super cool. Yeah, it was surprising, actually, to the researchers. But there was another surprise that happened along the way. Franz almost lost the nodules.

He got an email from customs about the package the nodules were in, and they said that soil imports aren't allowed, and they told him. The package will be destroyed. And I was like, what? I was in a faculty meeting when that happened. Oh, dang customs! Yeah, well, okay, so he then scour the shipping rules and found that soil of oceanic origins can be imported without any issues

and this saved the nodules samples. Soil of oceanic origin loophole. Yes. Okay. Your legal background is coming through. Yes. I want to stay in the ocean. Our final stories about waves gone rogue.

What the heck, guys? Yeah. So rogue waves are these abnormally large waves that seem to come out of nowhere and they endanger ships at sea. Our colleague Nell Greenfield-Boyce reported that advances in AI could someday help predict them. Huh. Okay. So when you say abnormally large waves, like,

How big are we talking? For a wave to be rogue, it has to be over twice the size of the surrounding waves at a given time. So it depends on the size of the waves in the area. For centuries, scientists thought these waves were a sailing myth until a scientific instrument managed to record one that measured 84 feet. Whoa. Yeah. And rogue waves are dangerous. They can damage ships, infrastructure, cause power failures, and really hurt people. A cruise ship passenger died and others were injured when a freak wave hit the Viking Polaris in 2020. Oh, my God, it's terrible.

Yeah. Yeah, there's no way of predicting them, but a new study suggests that actually it may be possible to use information from floating buoys to give people some advanced warning. So, researchers have developed a computer system that correctly predicted 73% of these rogue waves five minutes before they occurred, which is valuable. It's like an earthquake warning, you know. With some time, oil rig workers or ship passengers can seek shelter, perform emergency shutdowns or evacuating. If people on the ocean had a little more time, that would help. Wow. Well, how did these researchers figure out how to predict these waves? Yeah, so a researcher with the University of Maryland, Bala, Bala Chandran, and his colleagues trained a neural network using data from 172 buoys off the coast of the continental U.S. and the Pacific Islands.

All of that data helped train the computer system to recognize waves that occurred right before a rogue wave happened and also to distinguish them from waves that weren't followed by a rogue wave. The scientists say they still have to improve the system's accuracy, but this could be the start of a powerful tool that could even lead to better forecasting for other extreme events. That's pretty awesome. Yeah, it really is. And Elsa, thank you so much for hanging out with us. You're always welcome. You're always amazing. Thank you.

I always feel welcome. I love it here. This is the good place. It is the good place. You can catch more of Elsa doing her day job hosting the news on Consider This and Pyrr's Afternoon News Podcast. Before we head out, a quick shout out to our Shortwave Plus listeners. We appreciate you and we thank you for supporting our show. Shortwave Plus helps support our show and if you're a regular listener, we'd love for you to join so you can enjoy the show without sponsor interruptions.

Find out more at plus.mpr.mpr.org slash shortwave. This episode was produced by Kira Joaquin and Rachel Carlson. It was edited by Rebecca Ramirez and Christopher Inteliotta. Emily, Rebecca, Rachel and I checked the facts. and the audio engineer was Valentina Rodriguez-Sanchez. I'm Regina Barber, and I'm Emily Kwong. Thanks for listening to Shortwave, the science podcast from NPR.