Black-capped chickadees use memory skills to remember food sources : Short Wave Tiny, black-capped chickadees have big memories. They stash food in hundreds to thousands of locations in the wild – and then come back to these stashes when other food sources are low. Now, researchers at Columbia University's Zuckerman Institute think neural activity that works like a barcode may be to thank for this impressive feat — and that it might be a clue for how memories work across species.

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The "barcodes" powering these tiny songbirds' memories may also help human memory

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EMILY KWONG, BYLINE: You're listening to SHORT WAVE...

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KWONG: ...From NPR.

REGINA BARBER, HOST:

Hey, SHORT WAVErs. Regina Barber here. And this time, I've got two of our favorites for our regular roundup of science news. Ari Shapiro.

ARI SHAPIRO, BYLINE: I'm one of your favorites? Thank you.

BARBER: You really are, honestly.

SHAPIRO: (Laughter).

BARBER: And Rachel Carlson. Hey, Rachel.

RACHEL CARLSON, BYLINE: Also hopefully one of your favorites.

BARBER: Absolutely, absolutely. As you both know, we're going to share 3 science stories in the news that have caught our attention recently.

SHAPIRO: I'm excited to hear the one about impressive memories of chickadees.

BARBER: Yeah.

CARLSON: I'm scared for the one about robots that anticipate your smile.

BARBER: Not me. But finally, there's also a story about insects and poetry, specifically haiku. All that on this episode of SHORT WAVE, the science podcast from NPR.

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BARBER: All right. Ari, as our guest, which topic do you want to start with? Which calls to you the most?

SHAPIRO: Eenie, meenie, minie, mo. I'm going to choose the chickadees with the big memories.

CARLSON: OK, Ari. So researchers at Columbia University were studying black-capped chickadees. They really do look like they're wearing a black hat, and these tiny birds are notorious for their big, big memories. In the wild, they stash seeds in hundreds, sometimes thousands of different places, and then they go back to those seeds later. So it's exactly like when I hide stashes of granola all over the office for those classic, treacherous Culver City winters.

BARBER: (Laughter) And these memories are often a matter of life or death for them in colder months because food sources are lacking.

SHAPIRO: Do scientists know how these very small birds with these very small brains remember where hundreds or thousands of seeds are located?

CARLSON: So researchers recently observed that each time these birds hide a seed in a specific location, a unique brain pattern fires off in the hippocampus, which is a part of the brain that's critical for memory. The scientists liken this pattern to something like a barcode. The work was published last week in the journal Cell.

SHAPIRO: How did scientists figure that out?

BARBER: Yeah, so these teams built these arenas with feeders full of sunflower seeds and small perches with flaps for birds to hide the seeds.

SHAPIRO: Wow.

CARLSON: The researchers tracked the birds' neural activity with small probes inserted inside of their brains, and each time a bird hid a seed under a flap, they noticed a unique brain pattern associated with each hiding spot.

BARBER: And what's even cooler is that the same barcode-like activity popped up again if the chickadee went back to that specific site and successfully retrieved the seed but not when the bird just visited the site.

SHAPIRO: Wow. So, like, the barcode is more connected, then, to the experience than it is to the place?

CARLSON: Yeah. I talked to one of the authors on the study, Selmaan Chettih, and he told me that these barcodes might be a new framework for how the brain binds together a bunch of information, like time, place, context, into a single memory for these birds and possibly for humans.

SHAPIRO: Cool. All right. Gina, from birds to machines, you're going to tell us about a robot that smiles, which sounds like something out of a horror movie like "M3GAN." I watched that on an airplane.

CARLSON: Yes.

SHAPIRO: Is that what this is?

BARBER: I mean, I love robots. I'm not horrified. So let's talk about robotics because it's come a long way in, like, verbal communication using AI, but that's not the only kind of communication.

HOD LIPSON: We humans communicate with each other in much more sophisticated ways, through body language and through facial expressions.

BARBER: That's Hod Lipson, and he's a roboticist at Columbia University. He's part of a team that recently published a study in the journal Science Robotics, and it's describing a robotic face his team created called Emo.

CARLSON: And Emo is a new kind of robot because instead of having preprogrammed facial reactions, it uses AI to learn how to smile by watching hours of YouTube and watching itself in the mirror. So now, when it's interacting with a human, it can anticipate the person's smile before that happens and then smile at the same time.

SHAPIRO: You can't hear this on the radio, but I'm raising my eyebrows right now.

BARBER: He is. He is.

CARLSON: (Laughter) What you're probably feeling is usually described as the uncanny valley, which is this super eerie space where a robot is almost perfectly human but not quite. So you feel connected to the robot until you realize that its mouth isn't quite syncing up with the words it's saying or something like that. And then that connection becomes something more like disgust.

BARBER: Yeah. So Yuhang Hu, a Ph.D. student and the lead author in the study, says Emo is just, like, the beginning of getting over this uncanny valley and that we shouldn't think of it as human.

YUHANG HU: We're not doing 100% human. We're trying to create a new species.

SHAPIRO: Oh, no. What should we expect from this new species - apart from total annihilation of humankind?

BARBER: (Laughter). I mean, I don't believe that. But both Hod and Yuhang say Emo is still just in the early stages. It's, like, a baby that knows how to smile, but it doesn't know why you smile. So context is something that Emo can get better at and even learn different reactions in different cultures.

CARLSON: And all of this could help researchers overcome that uncanny valley, which is really important for developing realistic robots that could be useful for things like caretaking. Eve Herold, the author of a book on social robots, told us Emo takes the illusion of aliveness to a whole new level and could make people feel like they're in sync with a living, experiencing intelligence like ourselves.

SHAPIRO: Oof (ph).

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SHAPIRO: Well, let's end this science news roundup with some poetry...

BARBER: Yes.

SHAPIRO: ...Haiku and insects.

BARBER: Yeah. So haiku, for those unfamiliar, are very short poems. They originated in Japan. And the form started with certain rules, but it's been picked up and adapted as it spreads to other languages. It often depicts a single moment and has traditionally referenced nature, including insects.

CARLSON: Like this one that we'd like you, Ari, to read from Japanese poet Kobayashi Issa. It was written in 1821 and then translated into English.

SHAPIRO: OK, I'm looking at this for the first time. But I have to flag for you science experts that the creature in this haiku is not an insect. It reads...

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SHAPIRO: ...(Reading) Corner spider, rest easy. My soot broom is idle.

BARBER: It's very...

SHAPIRO: As we all know...

CARLSON: You've got to love...

SHAPIRO: ...A spider has eight legs, not six.

BARBER: Oh, wow...

SHAPIRO: It is an arachnid.

CARLSON: But you do got to love a soot broom.

SHAPIRO: Yeah. I like that.

CARLSON: Yeah. So researchers at the Frost Entomological Museum at Penn State analyzed thousands of haiku written over centuries - in English or translated into English - that referenced arthropods. So that includes insects and other animals with jointed appendages...

BARBER: See?

CARLSON: ...And exoskeletons.

SHAPIRO: Like crayfish.

CARLSON: They wanted to see what arthropods get referenced the most and which ones get sadly overlooked.

SHAPIRO: Which arthropod is the winner?

BARBER: So the researchers published the results of their study this week in PLOS One. And they found that - maybe no surprise - the Lepidoptera group...

SHAPIRO: Oh, butterflies and moths. Yeah.

BARBER: ...Yeah - get referenced the most. Here's another haiku from Issa. (Reading) Fresh-scooped mud from the little ditch - a little flitting butterfly.

CARLSON: And the paper also tracked which behaviors get referenced. And for butterflies, it was flight or flitting. One of the researchers, Andrew Deans, told us butterflies often engage in a behavior called puddling, where they suck up liquids from, like, mud or riverbanks for the salt and amino acids. So that could be what this haiku Gina just read is capturing.

SHAPIRO: You know, I've seen butterflies do that and never known why. Now I know.

CARLSON: There you go.

SHAPIRO: All right. Which arthropods get sadly overlooked?

BARBER: So aquatic arthropods.

SHAPIRO: Oh, like the crayfish.

BARBER: (Laughter) So, for example, the study cites aquatic insects that live part of their lifecycle in water, like caddisflies or stoneflies. And they're very common, and they're important to the ecosystem. But they found few or zero references to them in the haikus they looked at.

CARLSON: But, Ari, you are in luck. The Frost Entomological Museum is holding its annual Hexapod Haiku Challenge right now. It's free, and anyone can enter. And a special category this year is aquatic arthropods. So you can really be the one to make sure stoneflies - and crayfish if you want - finally get their due.

SHAPIRO: True story - when I was a kid, I won a poetry contest...

BARBER: What?

SHAPIRO: ...With the Oregon Zoo, where you had to write a poem about one of the animals at the zoo. So I think...

BARBER: What animal?

SHAPIRO: I wrote about the hippopotamus, which is not easy to rhyme with.

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BARBER: Ari, thank you so much for hanging out with us. It's a pleasure every time.

SHAPIRO: Always a delight. Thanks for having me.

CARLSON: You can also catch Ari on Consider This, NPR's afternoon news podcast.

BARBER: And before we head out, a quick shout-out to our SHORT WAVE+ listeners. We appreciate you, and we thank you for being a subscriber. SHORT WAVE+ 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.npr.org/shortwave.

CARLSON: This episode was produced by Vincent Acovino and Berly McCoy. It was edited by Rebecca Ramirez, Viet Le and Christopher Intagliata.

BARBER: Rebecca and Rachel checked the facts. And the audio engineers were Valentina Rodriguez Sanchez and Patrick Murray. I'm Regina Barber.

CARLSON: I'm Rachel Carlson.

BARBER: Thank you for listening to SHORT WAVE from NPR.

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