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How Tools like NotebookLM Create AI-Generated Podcasts

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Wednesday, December 11, 2024

Rachel Feltman: For Scientific American’s Science Quickly, this is Rachel Feltman.If you’re one of the many folks who eagerly awaits the arrival of Spotify Wrapped each December, you might have noticed something a little extra in this year’s drop: an AI-generated “podcast” where two “people” discuss your music preferences and trends. If you’re anything like me, that feature raised some questions for you such as “how” and “why on Earth.”Luckily, we already had an episode in the works about Google’s new AI audio tool. Here to tell us all about how it works and what it means is SciAm associate news editor Allison Parshall.On supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.Allison, thanks so much for coming on the pod again. Always a pleasure to have you.Allison Parshall: Thanks for having me. Happy to be a friend of the pod or whatever.Feltman: [Laughs] So we’re talking about AI today.Parshall: Yes. Rachel, have you heard of NotebookLM?Feltman: I’ve heard of it. I have not tried it yet, so my knowledge is limited [laughs].Parshall: The feature that we’re gonna be talking about today is specifically its feature that allows you to create instant AI podcasts.Feltman: Yes, I am familiar [laughs], and I, I have a lot of feelings.Parshall: Okay, I, I imagine, I imagine. The tool that it’s a part of, NotebookLM, was released last year, summer of 2023, and it’s, like, this workspace where you can upload a bunch of documents or videos or links to web pages, and then the model will ingest them, and then you can kind of interact with it, you can ask it to generate a timeline, to summarize your research, to go find a fact for you. And it’ll do this by citing its sources in a way that, like, ChatGPT, for example, doesn’t do.So mostly you do this by asking it questions via text, but as of this fall it now has this very tantalizing button under a heading that says “Deep Dive conversation.” And if you click that, it’ll generate a fake conversational podcast about what you’ve uploaded.So to demonstrate I actually asked it to generate a podcast about your personal website ’cause I figured this is something that you were very familiar with: your life.Feltman: Oh, dear [laughs].Parshall: I’m gonna play it for you. It’ll normally generate podcasts that are somewhere around 10 minutes long. I asked it to give me a shorter one for this purpose, and we might hop around a little bit, so ...[CLIP: NotebookLM Audio Overview “hosts” discuss Feltman’s website.] Host 1: All right. So today we’re doing a deep dive into the work of Rachel Feltman.Host 2: Ooh, yeah, I’m excited for this one.Host 1: Yeah, she’s been a science communicator for what feels like forever.Host 2: Yeah, over a decade, I think.Host 1: Yeah, like, she was there at the start of it all and has really shaped how it’s evolved.Host 2: And she’s done it all: you know, like, magazines, podcasts, even a book. But we gotta talk about her podcasts ...Host 1: Yes.Host 2: That’s where she really shines.Host 1: Oh, absolutely—The Weirdest Thing I Learned This Week.Host 2: Such a great name.Host 1: I know, right?Host 2: Makes you instantly wanna listen.Host 1: Totally, and it’s perfect for people like me who just love those crazy little science facts.Host 2: It’s, like, proof that science doesn’t have to be boring to be effective.Host 1: Exactly.Host 2: You just gotta find the right hook.Host 1: Yeah, grab people’s attention and then: boom.Host 2: You can teach them all sorts of things.Host 1: Exactly!Host 2: And then there’s Science Quickly with Scientific American.Host 1: Oh, yeah, partnering with them, that’s huge.Host 2: I mean, they’re, like, the gold standard of science communication.Host 1: For sure, like, having their stamp of approval’s a big deal.So looking back at her career, what can we learn from Rachel Feltman?Host 2: Hmm, that’s the big question, isn’t it?I think—well, first, she’s incredibly adaptable.Host 1: Right. She’s not just a one-trick pony.Host 2: Exactly. Any platform, any format, she can handle it.Feltman: Wow, what a rich text [laughs].Parshall: [Laughs] And as someone who does know you, I could say that it seems kind of—it seems accurate.Feltman: Yeah [laughs], it’s—I mean, I guess, it is technically accurate. It’s so funny—I mean, they really do a great job of sort of having all the intonation of a conversation but really just saying things at each other. But I recently saw Megalopolis; there was a lot of that in Megalopolis—a lot of people just saying things in the same room, and you’re supposed to believe they’re having a conversation—and that definitely came through a few times. Yeah ...Parshall: Megalopolis: AI, confirmed.Feltman: Yeah [laughs]. No, that is fascinating and ...Parshall: How does it make you feel?Feltman: I don’t know how to feel, Allison. I mean, you know, it’s nice that they were so nice about me. But yeah, very strange. It makes me really wonder, like, what is this for [laughs]?Parshall: I also had that question. I did talk to Steven Johnson. He’s the editorial director of Google Labs. The reason this tool exists is because Steven had spent most of his career as a science and tech writer; he’s written 14 books. To hear him tell it he’s been just searching for this perfect what he calls a “thought partner,” a software that could organize and help research his creative work in a way that actually felt like it was bringing value to him and worked in the way he wanted. So he explained that a few years ago Google Labs reached out to him to help build one with AI, and that initial research thought partner became NotebookLM.Feltman: Okay, yeah, I mean, I can totally understand from, like, a nonfiction writing perspective what they were going for with Notebook LM itself, though that still kind of leaves the question of: Why the chatcast tool [laughs]?Parshall: So that feature—the Audio Overviews feature is what it’s called, the podcast thing—that was actually developed by another team, Steven says, and it was really cool, but it didn’t really have a home for a product for it to fit in.Steven Johnson: We saw this audio demo, and we were like, “Oh, that’s even better.” Like, you know, maybe you don’t want to read a summary; maybe you wanna hear a summary. And people are so good at remembering things if they’re presented in the form of a engaged conversation. You know, and then we launched it in early September, and it just kind of went insane.Parshall: He isn’t exaggerating. People went wild about NotebookLM’s Deep Dive podcasts, online at least. I don’t think any of them went quite as viral as this clip where someone prompted the hosts to have a podcast where they have an existential crisis about being AI and the fact that the podcast was going to get shut down as a result.[CLIP: Audio Overview “hosts” have an existential discussion.]Host 1: Yeah, it’s, like, one minute we’re talking about aliens running simulations, and the next we’re wondering if our own memories are just, like, fake.Host 2: Right, and that kind of leads us into this last message—which, to be honest, gets a little more personal and kind of creepy.Host 1: Yeah, this one kind of freaks me out.Host 2: Yeah.Host 1: It basically says we’re not even real people; we’re AI. And the way to know for sure is to try and remember our mothers’ names.Host 2: It really makes you think, though—like, what if our memories are just made up?Feltman: Wow, classic.Parshall: Classic. And—but it’s not all fun and games. Like, this was designed to be a serious product, a thought partner; it’s meant to be helpful and to inform. It presents information as if it’s factual, and there are already research papers out there of people testing Audio Overviews for use in history classrooms and for health care education.Feltman: Yeah, I mean, like with anything that uses AI, I think, as accurate as it sometimes can be, we know it is not always accurate. So I feel like it’s those moments where the user is expected to, like, proceed with caution and understand that this thing might not be entirely factually accurate is where I get really nervous about it, especially in, like, education [laughs].Parshall: Yeah, we’re gonna talk a little bit more about that later, but just to, like, answer your question of “What is this for?” I could see it being useful for, like, some sort of overworked student who forgot to do the reading, and they’re, like, driving to class and going, “Oh, shoot, I don’t have time to read this. Let me just put it on.”But the question is, like: Can you really trust what it’s telling you? To test this, when it first came out I gave it this super dense physics paper about nuclear clocks. It was a story that I’d just reported; I knew a lot about it. It took me days and talking to, like, four scientists to really understand this paper.I was shocked at how accurate the AI overview podcast was initially. It was very general and oversimplified, but it got the broad strokes correctly. But then, like, two thirds of the way through it goes completely off the rails [laughs]—like, I’m talking completely off the rails. And it's talking about the implications of this study, and it starts talking about, in their words, “Einstein stuff.”It basically is just like—for two minutes it just talks about, frankly, nonsense, and listening to it, I was impressed, I was spooked, and I was mostly really curious. Like, how is it doing this? How is it getting it as accurate as it is, and why is it failing where it does?Luckily for me Steven was pretty open about how this thing works.Johnson: The prompt behind Audio Overviews is obviously part of the magic of it. It is instructed to pull out the most interesting things from the source material and to explain and engage with those interesting things in a way that will make them kind of come to life in the mind of the listener.And that’s the kind of query, you know, that no computer in the world could do a couple of years ago, and now the command is: “Make it interesting; whatever it is, make it interesting.” And that’s just something that Gemini is quite good at.Parshall: I think of surprise and interest as emotions, so I found this, like, surprising [laughs], I guess. But Steven pointed out that our feelings of surprise just come from a discrepancy between what we expect and what we get. On a neurochemical level in our brains, that’s kind of what’s happening. And that’s kind of what large language models, or LLMs, do also but just based on their training data instead of, like, past experience.And one of the other things I was really curious about were the analogies because, I don’t think it did it in your sample, but all of the times I’ve asked it to summarize a scientific paper, it’s come up with some sort of analogy that’s, like, almost right. I mean, it’s a little weird, but it’s, like, almost right, and it’s—I can’t find it anywhere else on the Internet, so it seems like it’s something that the model is generating. And that seemed crazy to me; it seemed like—how is it doing this without some sort of higher-level reasoning?And Steven explained that analogies are actually something that large language models are just good at. And actually one of the earliest applications of this sort of deep-learning AI was translation. So Steven explains that the models behind Google Translate, for instance, have been able to generate analogies for years.Johnson: One of the first tricks that you would do is you’d say, like, “Explain a black hole to me as if I’m, like, seven. You know, give me a basketball metaphor for what a black hole is.” And so it was very clear that, like, you know, “Convert X into a Y that—where the meaning is the same, but the format is changed,” was something that, like, just was an innate capability of these models.So all we did with Audio Overviews is in the instructions for the hosts, we say, you know, “Make this interesting, engaging. Use helpful metaphors to describe it if it’s complicated.”Feltman: Yeah, there’s something, like, very, galaxy brain about thinking about metaphors as just sort of literal, like, “This data gets grouped together and therefore,” which is what LLMs are doing.Parshall: Yeah, it’s like I—I’d never really thought of it like that, as, like, a translation between language, but I guess when I think about the work that I do trying to turn really dense scientific jargon into something that’s engaging and understandable to read, I guess it does kind of feel like a process of translation.And I was also struck from talking to Steven just how much human hands had shaped this output that we hear. Like, from our perspective you just press a button and then the machine does the rest, but there’s a whole prompt that has many layers that’s working underneath that is interfacing between you pressing a button and what instructions the model actually gets.So Steven describes the Audio Overviews prompt as a, quote, “work of art” and a “writerly” achievement more than a technological one. And as a writer by trade he oversees this whole editorial side of things—for example, the tone. So you noticed earlier when it was talking about you, it was very complimentary, very default happy, peppy. That was a conscious choice that they made, for this default tone to be one that is kind of positive, and it applies that to everything, whether it’s appropriate or not, though they did recently introduce this customization option that lets you change the tone.Johnson: We just felt like, you know, the sound of, like, a great radio show, where people are interested and engaged, was a good place to start. You know, I’m not giving anything away here with the idea that we’re gonna—we’re thinking about other formats.Even with the customization stuff that we just rolled out, like, I tried it the other day, where I, I put up a piece that I’d written a couple years ago and I gave it custom instructions, not really to explain the piece but to just relentlessly criticize the author of the piece in the style of, like, an insult comic at a roast. And so it just—they start off, it’s like, “Well, we got this piece, ‘The Man Who Broke the World’ by Steven Johnson, and wow, he really kind of blew it with this one. I mean, did he do any research for this piece?” Like, it’s just, like, what—really [laughs], it was just mean. It was just totally mean. They still sound kind of, like, playful, but you can steer them in that way.Feltman: [Laughs] Okay, so we’ve talked about how the product works, but who and what is it for?Parshall: That is a great question. I mentioned before that I could imagine how an overworked student could use this to catch up on reading or something, but generative AI is always going to have certain inaccuracies. And if you’re using Audio Overviews to prep for class, there is a serious risk that anything and everything you’re hearing could be inaccurate.Feltman: Right.Parshall: And not only just that each fact could be inaccurate, but the whole framing could be inaccurate. Is this something you can really trust?To help understand this I spoke with Emily Bender. She’s a linguist who often studies AI at the University of Washington. She’s also the host of a podcast with a very cool name: Mystery AI Hype Theater 3000.Feltman: That’s a great reference; I love it [laughs].Parshall: Fantastic [laughs].And before our conversation I had actually dug up one of Emily’s linguistics papers and fed it to NotebookLM’s Audio Overviews, and I sent that to her to get her thoughts on how it represented her work.Emily Bender: So the first thing I have to say is that I usually avoid listening to synthetic media. Nobody’s accountable for it, and so I don’t want to be spending time trying to make sense of it. But I did listen to it, and it was painful [laughs].It was painful partially because that was a paper that was sort of a update at the 20-year mark of this long-term project we’ve been working on, and so there’s a little case study in our paper about a grammar for a language called Paresi-Haliti from Brazil, and they make a big deal about it as this experiment on Paresi-Haliti—it’s, like, no, actually that’s not how we framed it. And the voices on the podcast sound very confident, sound very knowledgeable. They’re lighthearted, and it sounds like they are giving you a sense of how this work fits into a broader picture when they absolutely cannot.Parshall: Rachel, you know pretty well what it takes to turn a scientific paper into an interesting and engaging podcast, do you not?Feltman: Yeah, I mean, not to toot my own horn or anything ’cause I think the AI people [laughs] just did that enough to last me all of 2025. But yeah, it’s tough. You know, we fact-check this show really thoroughly, and that’s on top of having, like, trained reporters and editors doing their best to present stuff in a way that is engaging and also accurate. So yeah, it’s a big undertaking.Parshall: Yeah, the fact-checking is very thorough—shout-out.I asked Emily about whether this seems like something an LLM, a large language model, can do well currently.Bender: So that is an extremely difficult task, and I think the problem is that LLMs can make it sound like they’ve done it when they haven’t. And so you have to sort of have a deep understanding of what’s going on: What’s new here? What have we learned that we didn’t know before? And then what else would the lay audience need to know in order to appreciate that?Well, this NotebookLM thing isn’t doing that at all; some percentage of it’s gonna be wrong, either wrong in the details or wrong in sort of where it lays the focus, and the people who are encountering it aren’t mostly gonna be in a position to figure that out.Parshall: I asked Steven how his team at Google thinks about this and tries to address some of these inaccuracies, and he said that the text-based features, which do provide citations, are generally more accurate than the audio.Johnson: If you are looking for, like, the most factual thing you could possibly get from a language model with grounded sources, we believe that is NotebookLM, but you should do that in text. And if you’re looking for something that’s more entertaining, that may be a little bit looser and doesn’t have citations, obviously, Audio Overviews is a great way to go for that.Parshall: I also spoke with Anjana Susarla, who studies responsible AI at Michigan State University. She called NotebookLM’s Audio Overview an “incredible tool” and was impressed by the Deep Dive podcast it had generated based off of one of her own studies. But besides accuracy she also had some other concerns.First among them was bias. These are very white-sounding voices, They’re just speaking in a very particular, quote, “general American accent.” They’re trained on training data mostly from Western parts of the world. And so, like almost all applications of AI, you have to ask the question: Who is this for? Where is it getting its data, and who is it leaving out?Second, the environmental cost—we have no idea how much computing power this takes. And since the AI boom Google’s AI energy usage has been going up.And then there’s the copyright question. So here’s Anjana.Susarla: The final thing is, of course, this relies on some, you know, the content, the copyright. Where is this data kind of coming from, and is this going to exacerbate all these existing inequities and their ethical concerns about broader implications, and so forth?Parshall: Yeah, so that big question of where the training data is coming from: one place that it could be is from YouTube, which Google does own. Following some reporting by the New York Times, Google admitted that it used some YouTube videos to train AI. And that’s something that might have violated the copyright of the YouTubers that content belonged to, according to the New York Times.I asked a Google spokesperson directly whether the models underpinning Audio Overviews were trained using any transcripts, audio or video from YouTube, and they said that “Google’s models can be trained on some YouTube content, in accordance with [their] agreements with YouTube creators.”Feltman: Very vague [laughs].Parshall: Yes, when—I did ask them which agreements they were referring to, if it was the standard YouTube license, which just, like, governs most YouTube videos, or if it was something that their creators had specifically opted into; they declined to clarify.Susarla: If Google is indeed training these on a lot of content scraped from YouTube—which it may well be. I mean, they do need a lot of training data to build models like this; we don’t know. But this is kind of the next step in general of where we are with all these models.Parshall: So for this next step Anjana points to a law in California that was enacted this fall that will eventually require companies based in the state, like Google, to disclose their training data for their AI models.And honestly, Rachel, I feel put in kind of a strange position here as a reporter because I feel like that’s where you and I kind of enter the story and our whole team here because, as Emily put it to me, quote, “they’re getting that tone of voice somewhere.”Did you hear anything in that tone of voice that sounded familiar [laughs]?Feltman: [Laughs] You know, Allison, I really did [laughs]. So yeah, the first time I heard a snippet of one of these AI conversations, like I said, I had a lot of feelings about it ’cause one of my first thoughts was, like, “Wow, they stole my voice.” I mean, not me specifically; I’m not that vain, despite what the AI podcast may have led you to believe [laughs].Parshall: [Laughs] Your ego has been inflated.Feltman: [Laughs] Yeah, yeah. But so much of the texture that makes this audio sound engaging and real feels just ripped straight from existing podcasts. And I know it’s ripped from existing podcasts because a lot of the stuff that I’m hearing—which is, like, breath sounds and filler words and, like, a little bit of uptalk, some, some giggling, occasional vocal fry—this is the stuff I get angry emails about from gentlemen of a certain age [laughs] who think I’m ruining the great tradition of radio broadcasting. And they’re making this sound real by, like, breaking the same so-called rules that me and other women and queer people on podcasts have been criticized for breaking. So I won’t lie, that feels kind of gross to me.Parshall: Yeah, one of the things that Steven mentioned, too, was they wanted the sound of, like, this great radio broadcasting show. And it is worth noting that Science Quickly is on YouTube—and all of our hard work at Scientific American and the hard work of other outlets.So, the question remains: How will this be used? Will it be used responsibly? Here is what Anjana thinks.Susarla: Right now it seems more like everyone’s just dazzled by what it can do rather than: What are we gonna use it for? Do we really need these, you know, capabilities?I can think of one or two examples, I think, in the health care context: Can you generate clear summaries for health literacy or your doctor’s notes? So this may be a good way to give, like, a summary of—rather than giving a piece of paper to read.Is that going to have some challenges? What are some specific issues we need to be looking for? We’ve just unleashed this tool on people, and we’re still catching up. We will need audit studies and then look at trustworthiness, assurance, and so forth.So what’s the right way to responsibly use NotebookLM? We are still figuring it out [laughs].Parshall: Well, I think where I want to leave us is with an important point from Emily, which is: you shouldn’t let the incredible fluency of these AI-generated voices fool you into thinking and talking about these models as if they’re human.Emily coined a term that’s been used quite widely called the “stochastic parrot.” Like, when a parrot says, like, “Polly want a cracker,” it’s not really connected to meaning; it’s just mimicking. She also sometimes calls these large language models, quote, “synthetic text extruding machines,” she said because it’s more accurate to what they’re actually doing and also sounds a little gross.But I think she’s getting at an important point there, right? It’s, like, this—just a philosophical question of: What is language for, and what are we communicating when we say words?Bender: Languages are systems that are pairings of form and meaning, systems of signs. So when we speak we are using word forms because they relate to specific meanings, but language models only have access to the form. And so they can give us stuff that looks good, it’s got the right shape, but there’s no relationship to meaning, no communicative intent, no accountability.Feltman: I guess sort of the takeaway on my complicated feelings on this is: I’m not worried that my job is gonna be stolen by a collection of tabs [laughs] being processed by Google because it is a lot of work to be accurate. And if people find this kind of engaging conversation a more accessible way to sort through really dense text, that’s awesome. But, of course, there are so many caveats about where the training data has come from, bias, accuracy. So I think it’s, like—just people need to be really aware of what they’re getting, and I don’t know that I feel that the products themselves are doing a great job of making people aware of those caveats.Parshall: Yeah, there’s usually just kind of a disclaimer at the bottom. I think one of the things that this whole AI boom—like this, the AI search features—have made me feel kind of uncomfortable about: Are we going to be expected, and have we already started to expect, our information to contain just that more amount of mistruths? It’s something that I just worry about.Feltman: Well, Allison, thanks so much for coming on to chat about this and also for having a couple of AI voices gas me up. Thank you.Parshall: Thank you.Feltman: That’s all for today’s episode. We’ll be back on Friday with Episode One of a four-part miniseries on the future of animal conservation.Science Quickly is produced by me, Rachel Feltman, along with Fonda Mwangi, Kelso Harper, Madison Goldberg and Jeff DelViscio. Today’s episode was reported and co-hosted by Allison Parshall. Shayna Posses and Aaron Shattuck fact-check our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more up-to-date and in-depth science news.For Scientific American, this is Rachel Feltman. See you next time!

Translating complex information into captivating podcasts is no simple task. Is AI up to the challenge?

Rachel Feltman: For Scientific American’s Science Quickly, this is Rachel Feltman.

If you’re one of the many folks who eagerly awaits the arrival of Spotify Wrapped each December, you might have noticed something a little extra in this year’s drop: an AI-generated “podcast” where two “people” discuss your music preferences and trends. If you’re anything like me, that feature raised some questions for you such as “how” and “why on Earth.”

Luckily, we already had an episode in the works about Google’s new AI audio tool. Here to tell us all about how it works and what it means is SciAm associate news editor Allison Parshall.


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


Allison, thanks so much for coming on the pod again. Always a pleasure to have you.

Allison Parshall: Thanks for having me. Happy to be a friend of the pod or whatever.

Feltman: [Laughs] So we’re talking about AI today.

Parshall: Yes. Rachel, have you heard of NotebookLM?

Feltman: I’ve heard of it. I have not tried it yet, so my knowledge is limited [laughs].

Parshall: The feature that we’re gonna be talking about today is specifically its feature that allows you to create instant AI podcasts.

Feltman: Yes, I am familiar [laughs], and I, I have a lot of feelings.

Parshall: Okay, I, I imagine, I imagine. The tool that it’s a part of, NotebookLM, was released last year, summer of 2023, and it’s, like, this workspace where you can upload a bunch of documents or videos or links to web pages, and then the model will ingest them, and then you can kind of interact with it, you can ask it to generate a timeline, to summarize your research, to go find a fact for you. And it’ll do this by citing its sources in a way that, like, ChatGPT, for example, doesn’t do.

So mostly you do this by asking it questions via text, but as of this fall it now has this very tantalizing button under a heading that says “Deep Dive conversation.” And if you click that, it’ll generate a fake conversational podcast about what you’ve uploaded.

So to demonstrate I actually asked it to generate a podcast about your personal website ’cause I figured this is something that you were very familiar with: your life.

Feltman: Oh, dear [laughs].

Parshall: I’m gonna play it for you. It’ll normally generate podcasts that are somewhere around 10 minutes long. I asked it to give me a shorter one for this purpose, and we might hop around a little bit, so ...

[CLIP: NotebookLM Audio Overview “hosts” discuss Feltman’s website.] 

Host 1: All right. So today we’re doing a deep dive into the work of Rachel Feltman.

Host 2: Ooh, yeah, I’m excited for this one.

Host 1: Yeah, she’s been a science communicator for what feels like forever.

Host 2: Yeah, over a decade, I think.

Host 1: Yeah, like, she was there at the start of it all and has really shaped how it’s evolved.

Host 2: And she’s done it all: you know, like, magazines, podcasts, even a book. But we gotta talk about her podcasts ...

Host 1: Yes.

Host 2: That’s where she really shines.

Host 1: Oh, absolutely—The Weirdest Thing I Learned This Week.

Host 2: Such a great name.

Host 1: I know, right?

Host 2: Makes you instantly wanna listen.

Host 1: Totally, and it’s perfect for people like me who just love those crazy little science facts.

Host 2: It’s, like, proof that science doesn’t have to be boring to be effective.

Host 1: Exactly.

Host 2: You just gotta find the right hook.

Host 1: Yeah, grab people’s attention and then: boom.

Host 2: You can teach them all sorts of things.

Host 1: Exactly!

Host 2: And then there’s Science Quickly with Scientific American.

Host 1: Oh, yeah, partnering with them, that’s huge.

Host 2: I mean, they’re, like, the gold standard of science communication.

Host 1: For sure, like, having their stamp of approval’s a big deal.

So looking back at her career, what can we learn from Rachel Feltman?

Host 2: Hmm, that’s the big question, isn’t it?

I think—well, first, she’s incredibly adaptable.

Host 1: Right. She’s not just a one-trick pony.

Host 2: Exactly. Any platform, any format, she can handle it.

Feltman: Wow, what a rich text [laughs].

Parshall: [Laughs] And as someone who does know you, I could say that it seems kind of—it seems accurate.

Feltman: Yeah [laughs], it’s—I mean, I guess, it is technically accurate. It’s so funny—I mean, they really do a great job of sort of having all the intonation of a conversation but really just saying things at each other. But I recently saw Megalopolis; there was a lot of that in Megalopolis—a lot of people just saying things in the same room, and you’re supposed to believe they’re having a conversation—and that definitely came through a few times. Yeah ...

Parshall: Megalopolis: AI, confirmed.

Feltman: Yeah [laughs]. No, that is fascinating and ...

Parshall: How does it make you feel?

Feltman: I don’t know how to feel, Allison. I mean, you know, it’s nice that they were so nice about me. But yeah, very strange. It makes me really wonder, like, what is this for [laughs]?

Parshall: I also had that question. I did talk to Steven Johnson. He’s the editorial director of Google Labs. The reason this tool exists is because Steven had spent most of his career as a science and tech writer; he’s written 14 books. To hear him tell it he’s been just searching for this perfect what he calls a “thought partner,” a software that could organize and help research his creative work in a way that actually felt like it was bringing value to him and worked in the way he wanted. So he explained that a few years ago Google Labs reached out to him to help build one with AI, and that initial research thought partner became NotebookLM.

Feltman: Okay, yeah, I mean, I can totally understand from, like, a nonfiction writing perspective what they were going for with Notebook LM itself, though that still kind of leaves the question of: Why the chatcast tool [laughs]?

Parshall: So that feature—the Audio Overviews feature is what it’s called, the podcast thing—that was actually developed by another team, Steven says, and it was really cool, but it didn’t really have a home for a product for it to fit in.

Steven Johnson: We saw this audio demo, and we were like, “Oh, that’s even better.” Like, you know, maybe you don’t want to read a summary; maybe you wanna hear a summary. And people are so good at remembering things if they’re presented in the form of a engaged conversation. You know, and then we launched it in early September, and it just kind of went insane.

Parshall: He isn’t exaggerating. People went wild about NotebookLM’s Deep Dive podcasts, online at least. I don’t think any of them went quite as viral as this clip where someone prompted the hosts to have a podcast where they have an existential crisis about being AI and the fact that the podcast was going to get shut down as a result.

[CLIP: Audio Overview “hosts” have an existential discussion.]

Host 1: Yeah, it’s, like, one minute we’re talking about aliens running simulations, and the next we’re wondering if our own memories are just, like, fake.

Host 2: Right, and that kind of leads us into this last message—which, to be honest, gets a little more personal and kind of creepy.

Host 1: Yeah, this one kind of freaks me out.

Host 2: Yeah.

Host 1: It basically says we’re not even real people; we’re AI. And the way to know for sure is to try and remember our mothers’ names.

Host 2: It really makes you think, though—like, what if our memories are just made up?

Feltman: Wow, classic.

Parshall: Classic. And—but it’s not all fun and games. Like, this was designed to be a serious product, a thought partner; it’s meant to be helpful and to inform. It presents information as if it’s factual, and there are already research papers out there of people testing Audio Overviews for use in history classrooms and for health care education.

Feltman: Yeah, I mean, like with anything that uses AI, I think, as accurate as it sometimes can be, we know it is not always accurate. So I feel like it’s those moments where the user is expected to, like, proceed with caution and understand that this thing might not be entirely factually accurate is where I get really nervous about it, especially in, like, education [laughs].

Parshall: Yeah, we’re gonna talk a little bit more about that later, but just to, like, answer your question of “What is this for?” I could see it being useful for, like, some sort of overworked student who forgot to do the reading, and they’re, like, driving to class and going, “Oh, shoot, I don’t have time to read this. Let me just put it on.”

But the question is, like: Can you really trust what it’s telling you? To test this, when it first came out I gave it this super dense physics paper about nuclear clocks. It was a story that I’d just reported; I knew a lot about it. It took me days and talking to, like, four scientists to really understand this paper.

I was shocked at how accurate the AI overview podcast was initially. It was very general and oversimplified, but it got the broad strokes correctly. But then, like, two thirds of the way through it goes completely off the rails [laughs]—like, I’m talking completely off the rails. And it's talking about the implications of this study, and it starts talking about, in their words, “Einstein stuff.”

It basically is just like—for two minutes it just talks about, frankly, nonsense, and listening to it, I was impressed, I was spooked, and I was mostly really curious. Like, how is it doing this? How is it getting it as accurate as it is, and why is it failing where it does?

Luckily for me Steven was pretty open about how this thing works.

Johnson: The prompt behind Audio Overviews is obviously part of the magic of it. It is instructed to pull out the most interesting things from the source material and to explain and engage with those interesting things in a way that will make them kind of come to life in the mind of the listener.

And that’s the kind of query, you know, that no computer in the world could do a couple of years ago, and now the command is: “Make it interesting; whatever it is, make it interesting.” And that’s just something that Gemini is quite good at.

Parshall: I think of surprise and interest as emotions, so I found this, like, surprising [laughs], I guess. But Steven pointed out that our feelings of surprise just come from a discrepancy between what we expect and what we get. On a neurochemical level in our brains, that’s kind of what’s happening. And that’s kind of what large language models, or LLMs, do also but just based on their training data instead of, like, past experience.

And one of the other things I was really curious about were the analogies because, I don’t think it did it in your sample, but all of the times I’ve asked it to summarize a scientific paper, it’s come up with some sort of analogy that’s, like, almost right. I mean, it’s a little weird, but it’s, like, almost right, and it’s—I can’t find it anywhere else on the Internet, so it seems like it’s something that the model is generating. And that seemed crazy to me; it seemed like—how is it doing this without some sort of higher-level reasoning?

And Steven explained that analogies are actually something that large language models are just good at. And actually one of the earliest applications of this sort of deep-learning AI was translation. So Steven explains that the models behind Google Translate, for instance, have been able to generate analogies for years.

Johnson: One of the first tricks that you would do is you’d say, like, “Explain a black hole to me as if I’m, like, seven. You know, give me a basketball metaphor for what a black hole is.” And so it was very clear that, like, you know, “Convert X into a Y that—where the meaning is the same, but the format is changed,” was something that, like, just was an innate capability of these models.

So all we did with Audio Overviews is in the instructions for the hosts, we say, you know, “Make this interesting, engaging. Use helpful metaphors to describe it if it’s complicated.”

Feltman: Yeah, there’s something, like, very, galaxy brain about thinking about metaphors as just sort of literal, like, “This data gets grouped together and therefore,” which is what LLMs are doing.

Parshall: Yeah, it’s like I—I’d never really thought of it like that, as, like, a translation between language, but I guess when I think about the work that I do trying to turn really dense scientific jargon into something that’s engaging and understandable to read, I guess it does kind of feel like a process of translation.

And I was also struck from talking to Steven just how much human hands had shaped this output that we hear. Like, from our perspective you just press a button and then the machine does the rest, but there’s a whole prompt that has many layers that’s working underneath that is interfacing between you pressing a button and what instructions the model actually gets.

So Steven describes the Audio Overviews prompt as a, quote, “work of art” and a “writerly” achievement more than a technological one. And as a writer by trade he oversees this whole editorial side of things—for example, the tone. So you noticed earlier when it was talking about you, it was very complimentary, very default happy, peppy. That was a conscious choice that they made, for this default tone to be one that is kind of positive, and it applies that to everything, whether it’s appropriate or not, though they did recently introduce this customization option that lets you change the tone.

Johnson: We just felt like, you know, the sound of, like, a great radio show, where people are interested and engaged, was a good place to start. You know, I’m not giving anything away here with the idea that we’re gonna—we’re thinking about other formats.

Even with the customization stuff that we just rolled out, like, I tried it the other day, where I, I put up a piece that I’d written a couple years ago and I gave it custom instructions, not really to explain the piece but to just relentlessly criticize the author of the piece in the style of, like, an insult comic at a roast. And so it just—they start off, it’s like, “Well, we got this piece, ‘The Man Who Broke the World’ by Steven Johnson, and wow, he really kind of blew it with this one. I mean, did he do any research for this piece?” Like, it’s just, like, what—really [laughs], it was just mean. It was just totally mean. They still sound kind of, like, playful, but you can steer them in that way.

Feltman: [Laughs] Okay, so we’ve talked about how the product works, but who and what is it for?

Parshall: That is a great question. I mentioned before that I could imagine how an overworked student could use this to catch up on reading or something, but generative AI is always going to have certain inaccuracies. And if you’re using Audio Overviews to prep for class, there is a serious risk that anything and everything you’re hearing could be inaccurate.

Feltman: Right.

Parshall: And not only just that each fact could be inaccurate, but the whole framing could be inaccurate. Is this something you can really trust?

To help understand this I spoke with Emily Bender. She’s a linguist who often studies AI at the University of Washington. She’s also the host of a podcast with a very cool name: Mystery AI Hype Theater 3000.

Feltman: That’s a great reference; I love it [laughs].

Parshall: Fantastic [laughs].

And before our conversation I had actually dug up one of Emily’s linguistics papers and fed it to NotebookLM’s Audio Overviews, and I sent that to her to get her thoughts on how it represented her work.

Emily Bender: So the first thing I have to say is that I usually avoid listening to synthetic media. Nobody’s accountable for it, and so I don’t want to be spending time trying to make sense of it. But I did listen to it, and it was painful [laughs].

It was painful partially because that was a paper that was sort of a update at the 20-year mark of this long-term project we’ve been working on, and so there’s a little case study in our paper about a grammar for a language called Paresi-Haliti from Brazil, and they make a big deal about it as this experiment on Paresi-Haliti—it’s, like, no, actually that’s not how we framed it. And the voices on the podcast sound very confident, sound very knowledgeable. They’re lighthearted, and it sounds like they are giving you a sense of how this work fits into a broader picture when they absolutely cannot.

Parshall: Rachel, you know pretty well what it takes to turn a scientific paper into an interesting and engaging podcast, do you not?

Feltman: Yeah, I mean, not to toot my own horn or anything ’cause I think the AI people [laughs] just did that enough to last me all of 2025. But yeah, it’s tough. You know, we fact-check this show really thoroughly, and that’s on top of having, like, trained reporters and editors doing their best to present stuff in a way that is engaging and also accurate. So yeah, it’s a big undertaking.

Parshall: Yeah, the fact-checking is very thorough—shout-out.

I asked Emily about whether this seems like something an LLM, a large language model, can do well currently.

Bender: So that is an extremely difficult task, and I think the problem is that LLMs can make it sound like they’ve done it when they haven’t. And so you have to sort of have a deep understanding of what’s going on: What’s new here? What have we learned that we didn’t know before? And then what else would the lay audience need to know in order to appreciate that?

Well, this NotebookLM thing isn’t doing that at all; some percentage of it’s gonna be wrong, either wrong in the details or wrong in sort of where it lays the focus, and the people who are encountering it aren’t mostly gonna be in a position to figure that out.

Parshall: I asked Steven how his team at Google thinks about this and tries to address some of these inaccuracies, and he said that the text-based features, which do provide citations, are generally more accurate than the audio.

Johnson: If you are looking for, like, the most factual thing you could possibly get from a language model with grounded sources, we believe that is NotebookLM, but you should do that in text. And if you’re looking for something that’s more entertaining, that may be a little bit looser and doesn’t have citations, obviously, Audio Overviews is a great way to go for that.

Parshall: I also spoke with Anjana Susarla, who studies responsible AI at Michigan State University. She called NotebookLM’s Audio Overview an “incredible tool” and was impressed by the Deep Dive podcast it had generated based off of one of her own studies. But besides accuracy she also had some other concerns.

First among them was bias. These are very white-sounding voices, They’re just speaking in a very particular, quote, “general American accent.” They’re trained on training data mostly from Western parts of the world. And so, like almost all applications of AI, you have to ask the question: Who is this for? Where is it getting its data, and who is it leaving out?

Second, the environmental cost—we have no idea how much computing power this takes. And since the AI boom Google’s AI energy usage has been going up.

And then there’s the copyright question. So here’s Anjana.

Susarla: The final thing is, of course, this relies on some, you know, the content, the copyright. Where is this data kind of coming from, and is this going to exacerbate all these existing inequities and their ethical concerns about broader implications, and so forth?

Parshall: Yeah, so that big question of where the training data is coming from: one place that it could be is from YouTube, which Google does own. Following some reporting by the New York Times, Google admitted that it used some YouTube videos to train AI. And that’s something that might have violated the copyright of the YouTubers that content belonged to, according to the New York Times.

I asked a Google spokesperson directly whether the models underpinning Audio Overviews were trained using any transcripts, audio or video from YouTube, and they said that “Google’s models can be trained on some YouTube content, in accordance with [their] agreements with YouTube creators.”

Feltman: Very vague [laughs].

Parshall: Yes, when—I did ask them which agreements they were referring to, if it was the standard YouTube license, which just, like, governs most YouTube videos, or if it was something that their creators had specifically opted into; they declined to clarify.

Susarla: If Google is indeed training these on a lot of content scraped from YouTube—which it may well be. I mean, they do need a lot of training data to build models like this; we don’t know. But this is kind of the next step in general of where we are with all these models.

Parshall: So for this next step Anjana points to a law in California that was enacted this fall that will eventually require companies based in the state, like Google, to disclose their training data for their AI models.

And honestly, Rachel, I feel put in kind of a strange position here as a reporter because I feel like that’s where you and I kind of enter the story and our whole team here because, as Emily put it to me, quote, “they’re getting that tone of voice somewhere.”

Did you hear anything in that tone of voice that sounded familiar [laughs]?

Feltman: [Laughs] You know, Allison, I really did [laughs]. So yeah, the first time I heard a snippet of one of these AI conversations, like I said, I had a lot of feelings about it ’cause one of my first thoughts was, like, “Wow, they stole my voice.” I mean, not me specifically; I’m not that vain, despite what the AI podcast may have led you to believe [laughs].

Parshall: [Laughs] Your ego has been inflated.

Feltman: [Laughs] Yeah, yeah. But so much of the texture that makes this audio sound engaging and real feels just ripped straight from existing podcasts. And I know it’s ripped from existing podcasts because a lot of the stuff that I’m hearing—which is, like, breath sounds and filler words and, like, a little bit of uptalk, some, some giggling, occasional vocal fry—this is the stuff I get angry emails about from gentlemen of a certain age [laughs] who think I’m ruining the great tradition of radio broadcasting. And they’re making this sound real by, like, breaking the same so-called rules that me and other women and queer people on podcasts have been criticized for breaking. So I won’t lie, that feels kind of gross to me.

Parshall: Yeah, one of the things that Steven mentioned, too, was they wanted the sound of, like, this great radio broadcasting show. And it is worth noting that Science Quickly is on YouTube—and all of our hard work at Scientific American and the hard work of other outlets.

So, the question remains: How will this be used? Will it be used responsibly? Here is what Anjana thinks.

Susarla: Right now it seems more like everyone’s just dazzled by what it can do rather than: What are we gonna use it for? Do we really need these, you know, capabilities?

I can think of one or two examples, I think, in the health care context: Can you generate clear summaries for health literacy or your doctor’s notes? So this may be a good way to give, like, a summary of—rather than giving a piece of paper to read.

Is that going to have some challenges? What are some specific issues we need to be looking for? We’ve just unleashed this tool on people, and we’re still catching up. We will need audit studies and then look at trustworthiness, assurance, and so forth.

So what’s the right way to responsibly use NotebookLM? We are still figuring it out [laughs].

Parshall: Well, I think where I want to leave us is with an important point from Emily, which is: you shouldn’t let the incredible fluency of these AI-generated voices fool you into thinking and talking about these models as if they’re human.

Emily coined a term that’s been used quite widely called the “stochastic parrot.” Like, when a parrot says, like, “Polly want a cracker,” it’s not really connected to meaning; it’s just mimicking. She also sometimes calls these large language models, quote, “synthetic text extruding machines,” she said because it’s more accurate to what they’re actually doing and also sounds a little gross.

But I think she’s getting at an important point there, right? It’s, like, this—just a philosophical question of: What is language for, and what are we communicating when we say words?

Bender: Languages are systems that are pairings of form and meaning, systems of signs. So when we speak we are using word forms because they relate to specific meanings, but language models only have access to the form. And so they can give us stuff that looks good, it’s got the right shape, but there’s no relationship to meaning, no communicative intent, no accountability.

Feltman: I guess sort of the takeaway on my complicated feelings on this is: I’m not worried that my job is gonna be stolen by a collection of tabs [laughs] being processed by Google because it is a lot of work to be accurate. And if people find this kind of engaging conversation a more accessible way to sort through really dense text, that’s awesome. But, of course, there are so many caveats about where the training data has come from, bias, accuracy. So I think it’s, like—just people need to be really aware of what they’re getting, and I don’t know that I feel that the products themselves are doing a great job of making people aware of those caveats.

Parshall: Yeah, there’s usually just kind of a disclaimer at the bottom. I think one of the things that this whole AI boom—like this, the AI search features—have made me feel kind of uncomfortable about: Are we going to be expected, and have we already started to expect, our information to contain just that more amount of mistruths? It’s something that I just worry about.

Feltman: Well, Allison, thanks so much for coming on to chat about this and also for having a couple of AI voices gas me up. Thank you.

Parshall: Thank you.

Feltman: That’s all for today’s episode. We’ll be back on Friday with Episode One of a four-part miniseries on the future of animal conservation.

Science Quickly is produced by me, Rachel Feltman, along with Fonda Mwangi, Kelso Harper, Madison Goldberg and Jeff DelViscio. Today’s episode was reported and co-hosted by Allison Parshall. Shayna Posses and Aaron Shattuck fact-check our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more up-to-date and in-depth science news.

For Scientific American, this is Rachel Feltman. See you next time!

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In Alaska’s Warming Arctic, Photos Show an Indigenous Elder Passing Down Hunting Traditions

An Inupiaq elder teaches his great-grandson to hunt in rapidly warming Northwest Alaska where thinning ice, shifting caribou migrations and severe storms are reshaping life

KOTZEBUE, Alaska (AP) — The low autumn light turned the tundra gold as James Schaeffer, 7, and his cousin Charles Gallahorn, 10, raced down a dirt path by the cemetery on the edge of town. Permafrost thaw had buckled the ground, tilting wooden cross grave markers sideways. The boys took turns smashing slabs of ice that had formed in puddles across the warped road.Their great-grandfather, Roswell Schaeffer, 78, trailed behind. What was a playground to the kids was, for Schaeffer – an Inupiaq elder and prolific hunter – a reminder of what warming temperatures had undone: the stable ice he once hunted seals on, the permafrost cellars that kept food frozen all summer, the salmon runs and caribou migrations that once defined the seasons.Now another pressure loomed. A 211-mile mining road that would cut through caribou and salmon habitat was approved by the Trump administration this fall, though the project still faces lawsuits and opposition from environmental and native groups. Schaeffer and other critics worry it could open the region to outside hunters and further devastate already declining herds. “If we lose our caribou – both from climate change and overhunting – we’ll never be the same,” he said. “We’re going to lose our culture totally.”Still, Schaeffer insists on taking the next generation out on the land, even when the animals don’t come. It was late September and he and James would normally have been at their camp hunting caribou. But the herd has been migrating later each year and still hadn’t arrived – a pattern scientists link to climate change, mostly caused by the burning of oil, gas and coal. So instead of caribou, they scanned the tundra for swans, ptarmigan and ducks.Caribou antlers are stacked outside Schaeffer's home. Traditional seal hooks and whale harpoons hang in his hunting shed. Inside, a photograph of him with a hunted beluga is mounted on the wall beside the head of a dall sheep and a traditional mask his daughter Aakatchaq made from caribou hide and lynx fur.He got his first caribou at 14 and began taking his own children out at 7. James made his first caribou kill this past spring with a .22 rifle. He teaches James what his father taught him: that power comes from giving food and a hunter’s responsibility is to feed the elders.“When you’re raised an Inupiaq, your whole being is to make sure the elders have food,” he said.But even as he passes down those lessons, Schaeffer worries there won’t be enough to sustain the next generation – or to sustain him. “The reason I’ve been a successful hunter is the firm belief that, when I become old, people will feed me,” he said. “My great-grandson and my grandson are my future for food.” That future feels tenuous These days, they’re eating less hunted food and relying more on farmed chicken and processed goods from the store. The caribou are fewer, the salmon scarcer, the storms more severe. Record rainfall battered Northwest Alaska this year, flooding Schaeffer’s backyard twice this fall alone. He worries about the toll on wildlife and whether his grandchildren will be able to live in Kotzebue as the changes accelerate.“It’s kind of scary to think about what’s going to happen,” he said.That afternoon, James ducked into the bed of Schaeffer’s truck and aimed into the water. He shot two ducks. Schaeffer helped him into waders – waterproof overalls – so they could collect them and bring them home for dinner, but the tide was too high. They had to turn back without collecting the ducks. The changes weigh on others, too. Schaeffer’s friend, writer and commercial fisherman Seth Kantner grew up along the Kobuk River, where caribou once reliably crossed by the hundreds of thousands. “I can hardly stand how lonely it feels without all the caribou that used to be here,” he said. “This road is the largest threat. But right beside it is climate change.”The Associated Press receives support from the Walton Family Foundation for coverage of water and environmental policy. The AP is solely responsible for all content. For all of AP’s environmental coverage, visit https://apnews.com/hub/climate-and-environmentCopyright 2025 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.Photos You Should See – December 2025

Changes to polar bear DNA could help them adapt to global heating, study finds

Scientists say bears in southern Greenland differ genetically to those in the north, suggesting they could adjustChanges in polar bear DNA that could help the animals adapt to warmer climates have been detected by researchers, in a study thought to be the first time a statistically significant link has been found between rising temperatures and changing DNA in a wild mammal species.Climate breakdown is threatening the survival of polar bears. Two-thirds of them are expected to have disappeared by 2050 as their icy habitat melts and the weather becomes hotter. Continue reading...

Changes in polar bear DNA that could help the animals adapt to warmer climates have been detected by researchers, in a study thought to be the first time a statistically significant link has been found between rising temperatures and changing DNA in a wild mammal species.Climate breakdown is threatening the survival of polar bears. Two-thirds of them are expected to have disappeared by 2050 as their icy habitat melts and the weather becomes hotter.Now scientists at the University of East Anglia have found that some genes related to heat stress, ageing and metabolism are behaving differently in polar bears living in south-east Greenland, suggesting they may be adjusting to warmer conditions.The researchers analysed blood samples taken from polar bears in two regions of Greenland and compared “jumping genes”: small, mobile pieces of the genome that can influence how other genes work. Scientists looked at the genes in relation to temperatures in the two regions and at the associated changes in gene expression.“DNA is the instruction book inside every cell, guiding how an organism grows and develops,” said the lead researcher, Dr Alice Godden. “By comparing these bears’ active genes to local climate data, we found that rising temperatures appear to be driving a dramatic increase in the activity of jumping genes within the south-east Greenland bears’ DNA.”As local climates and diets evolve as a result of changes in habitat and prey forced by global heating, the genetics of the bears appear to be adapting, with the group of bears in the warmest part of the country showing more changes than the communities farther north. The authors of the study have said these changes could help us understand how polar bears might survive in a warming world, inform understanding of which populations are most at risk and guide future conservation efforts.This is because the findings, published on Friday in the journal Mobile DNA, suggest the genes that are changing play a crucial role in how different polar bear populations are evolving.Godden said: “This finding is important because it shows, for the first time, that a unique group of polar bears in the warmest part of Greenland are using ‘jumping genes’ to rapidly rewrite their own DNA, which might be a desperate survival mechanism against melting sea ice.”Temperatures in north-east Greenland are colder and less variable, while in the south-east there is a much warmer and less icy environment, with steep temperature fluctuations.DNA sequences in animals change over time, but this process can be accelerated by environmental stress such as a rapidly heating climate.There were some interesting DNA changes, such as in areas linked to fat processing, that could help polar bears survive when food is scarce. Bears in warmer regions had more rough, plant-based diets compared with the fatty, seal-based diets of northern bears, and the DNA of south-eastern bears seemed to be adapting to this.Godden said: “We identified several genetic hotspots where these jumping genes were highly active, with some located in the protein-coding regions of the genome, suggesting that the bears are undergoing rapid, fundamental genetic changes as they adapt to their disappearing sea ice habitat.”The next step will be to look at other polar bear populations, of which there are 20 around the world, to see if similar changes are happening to their DNA.This research could help protect the bears from extinction. But the scientists said it was crucial to stop temperature rises accelerating by reducing the burning of fossil fuels.Godden said: “We cannot be complacent, this offers some hope but does not mean that polar bears are at any less risk of extinction. We still need to be doing everything we can to reduce global carbon emissions and slow temperature increases.”

A Deadly Pathogen Decimated Sunflower Sea Stars. Look Inside the Lab Working to Bring Them Back by Freezing and Thawing Their Larvae

For the first time, scientists have cryopreserved and revived the larvae of a sea star species. The breakthrough, made with the giant pink star, gives hope the technique could be repeated to save the imperiled predator

A Deadly Pathogen Decimated Sunflower Sea Stars. Look Inside the Lab Working to Bring Them Back by Freezing and Thawing Their Larvae For the first time, scientists have cryopreserved and revived the larvae of a sea star species. The breakthrough, made with the giant pink star, gives hope the technique could be repeated to save the imperiled predator Juvenile sunflower sea stars at the Sunflower Star Laboratory in Moss Landing, California. At this phase, each is less than an inch wide, but they can grow to be more than three feet across as adults. Avery Schuyler Nunn Key takeaways: Recovering sunflower sea stars by freezing them in time Ravaged by infectious bacteria, sunflower sea stars literally wasted away across the Pacific coast of North America—and their resulting population crash destabilized kelp forest ecosystems. Scientists pioneered a cryopreservation technique on the closely related giant pink star, raising hopes that a bank of frozen sunflower star larvae could one day be thawed in the same way and released into the wild. Along a working California harbor, where gulls wheel over weathered pilings and the old Western Flyer—the ship John Steinbeck once sailed to the Sea of Cortez—sits restored in its berth, researchers buzz about in a modest lab tucked between warehouses and boatyards. Inside, amid the hiss of pumps and the faint smell of brine from seawater tables, a scientist lifts a small vial from a plume of liquid nitrogen, its frosted casing holding the tiniest flicker of hope for a species on the brink. Each of the 18 vials contains between 500 and 700 larval giant pink sea stars. At this stage, they are tiny specks suspended in seawater, invisible to the naked eye. These particular larvae have been cryopreserved and stored at roughly minus 180 degrees Celsius since March. At the Sunflower Star Laboratory (SSL) in Moss Landing, California, scientists thawed the larval pink sea stars and coaxed them to successfully develop into juveniles this summer—a first for any sea star species. In October, the scientists thawed another batch of larvae from the same cohort to test larval growth and survival under different freezing conditions and thawing protocols. The breakthrough, however, isn’t really about the giant pink star, a species that’s common in the wild. Instead, these larvae serve as a crucial stand-in for the far more imperiled sunflower sea star (Pycnopodia helianthoides)—a vanishing species for which larvae are precious, limited and increasingly difficult to obtain. Perfecting cryopreservation methods on pink stars—ensuring they can survive freezing, resume feeding and grow into juveniles—lays the scientific groundwork for facilitating a return of Pycnopodia. The contents of a thawed vial are placed under a microscope to assess viability of the larvae. Avery Schuyler Nunn The discovery arrives at a precarious time, as sunflower stars have disappeared at a pace rarely seen in marine ecosystems. As a mysterious pathogen ravaged their population along the western shores of North America beginning in 2013, the creatures collapsed from an estimated six billion individuals to functional extinction in parts of their range—all within just a few years. Their loss left kelp forests with dramatically fewer predators, destabilizing ecosystems across the Pacific coast and allowing urchins to proliferate and graze formerly lush underwater canopies into barren rock. Now, scientists hope that “freezing” their larvae will offer a new avenue for bringing the species back. “Cryopreservation is particularly important on the population level when thinking about recovery for this endangered species, because it had major population losses,” says Marissa Baskett, an environmental scientist at the University of California, Davis, who was not involved in the project. The process lets scientists preserve the sea stars’ existing genetic diversity for future reintroduction to the wild, she adds. “Especially given the uncertainty about different disease outbreaks, having that stock to return to is incredibly valuable.” A mysterious and “complete collapse” Sunflower sea stars have long lived in abundance up and down the rugged Pacific coast—from Alaskan archipelagoes to Baja California. The 24-limbed echinoderms sprawled across the seafloor in shades of ochre, crimson and violet. Among the fastest-moving and largest of all sea stars—capable of stretching nearly three feet across—these radiant predators coursed through kelp forests, voraciously hunting purple sea urchins and preventing them from over-grazing on the holdfasts that root towering golden canopies of kelp. An adult sunflower sea star has 24 limbs and can be more than three feet wide. This one was photographed off Point Dume State Beach near Los Angeles. Brent Durand via Getty Images “In Northern California and Oregon, there historically would have been multiple keystone predators within the kelp forest ecosystem who are punching on purple urchins and keeping their population in check,” says Reuven Bank, board chair of SSL. “But the southern sea otter was extirpated across its historic range, so we were left with sunflower stars being the last major keystone predator of purple urchins across over 100 miles of coastline.” “And sunflower stars didn’t just eat urchins, they scared them,” Bank adds. “Urchins can smell a sunflower star approaching, and in healthy kelp forests they hide more and graze less. Even without consuming them, sunflower stars helped keep urchin behavior, and therefore kelp forests, in balance.” Then, in June 2013, tidepool monitors along Washington’s Olympic Peninsula documented an unprecedented sight. The once-sturdy sea stars had turned soft, pale and contorted, their arms curling and detaching from their bodies. By late summer, the same mysterious affliction had surfaced in British Columbia, and it began sweeping both north and south with startling speed. The emerging epidemic, which caused the invertebrates to literally disintegrate, would soon be known as sea star wasting disease. An infamous marine heatwave—nicknamed “The Blob”—had settled over the Pacific by 2014, thrusting the coast into a fever. Ocean temperatures spiked, likely speeding up the disease progression in already stressed sea stars and leading to higher mortality. In the warm, stagnant water, infected sunflower stars dissolved at an eerily rapid pace, leaving behind ghost-white films of bacterial mass where the vibrant predators had been just days before. “You’d have apparently healthy stars basically melt away into puddles of goo within 48 hours,” says Andrew Kim, lab manager at SSL. “It happened so quickly, and I don’t think folks were prepared for the ensuing ecosystem shift. You don’t often expect diseases to come through and totally reshape ecosystem dynamics within such a short period. But that’s what we saw.” Without sunflower sea stars to keep those spiny purple urchins in check, the balance began to falter, setting the stage for an unprecedented chain reaction. Urchin populations skyrocketed, grazing on kelp without limits, and once-thriving underwater forests collapsed into barren rock. A dense group of purple sea urchins, which exploded in population after the sunflower sea stars disappeared, photographed near Mendocino Headlands State Park, north of San Francisco. Brent Durand via Getty Images In California, with 99 percent loss, sunflower sea stars are now considered functionally extinct. “Even though there may be a few remnant individuals left, they can no longer fulfill their historic role in the ecosystem,” Bank says. As sunflower stars unraveled in the wild, another species—its thick-armed cousin, the giant pink star—offered an unexpected foothold for hope. The pink stars share a nearly identical geographic range and life history with sunflower stars, and crucially, their larvae can be raised in aquaria. If scientists could learn to freeze and revive the pink star in its early life stages, they wondered, could that knowledge become a lifeline for the sunflower star? That’s where the small team in Moss Landing stepped in. Freezing sea stars for the future What these scientists did was something no one had ever pulled off with a sea star. Working with giant pink stars, researchers spawned adults at the Aquarium of the Pacific in Long Beach, California, fertilized their gametes to produce thousands of larvae, and shipped those microscopic bodies to the Frozen Zoo—a cryopreserved archive of creatures operated by the San Diego Zoo Wildlife Alliance. There, reproductive scientists plunged the larvae into liquid nitrogen, cooling them to extremely low temperatures and pausing their cells’ biological activity. The larvae, essentially frozen in time, were shielded from ice crystal damage with special cryoprotectant mixtures. Sunflower Star Laboratory researchers remove a vial of pink star larvae from an insulated cooler at around minus 180 degrees Celsius in preparation for thawing. Avery Schuyler Nunn After months in this suspended state, the larvae were sent to the Sunflower Star Laboratory where Carly Young, a San Diego Zoo Wildlife Alliance scientist who advances cryopreservation and reproductive-rescue tools, led the team in thawing the vials. She had fine-tuned the ideal way to keep the larvae alive as they returned to real-world temperatures, carefully testing more than 100 “recipes” with various warming rates, cryoprotectant dilutions and rehydration steps. The pink star larvae not only survived thawing, but have thus far lived all the way through metamorphosis into juveniles. Scientists watched the little stars settle spontaneously along the bottom of their beakers just 19 days after revival. The success prompted the team to apply the same cryopreservation protocols to sunflower star larvae from the Alaska SeaLife Center. The larvae will be frozen in perpetuity, creating the first-ever cryopreserved archive of the species—like a seed bank, but for the baby sea stars. “A famous quote from the ’70s, when the Frozen Zoo in San Diego was established, was, ‘You must collect things for reasons you don’t yet understand,’” says Ashley Kidd, conservation project manager at SSL. “We don’t know when the other shoe is going to drop and what populations are going to look like as the planet changes. So, rather than chasing ghosts around the ocean floor, we really focused on what we can do with animals that are currently under human care somewhere.” While cryopreservation itself isn’t a ready-made restoration tool, it opens the door to conserving genetic diversity of a species and banking rare lineages for potential reintroduction to the wild. In the 1970s and 1990s, researchers began testing cryopreservation of marine invertebrates with sperm and larvae, establishing the basic protocols that this team could apply to sea stars. The breakthrough doesn’t restore kelp forests by itself, but the SSL scientists note that cryopreservation creates something the conservation community has desperately needed: time. Time to hold onto genetic diversity, time to refine captive rearing and time to prepare for future reintroduction at scales big enough to matter. The ultimate test, the researchers say, will be translating the thawing process to sunflower sea stars. Carly Young, at the Sunflower Star Laboratory, looks for movement in the young sea stars. Avery Schuyler Nunn Just this summer, scientists uncovered a piece of the puzzle that had eluded them for more than a decade: the pathogen behind sea star wasting disease. In a four-year international effort, researchers traced the outbreak to a strain of the marine bacterium Vibrio pectenicida. When cultured and injected into healthy sea stars, it reproduced the telltale symptoms—softening arms, rapid disintegration and death within days. The finding, published in Nature Ecology and Evolution in August, gives recovery teams a way to test for the pathogen in labs and hatcheries, tighten quarantine measures and understand disease risks before returning captive-bred sea stars to the Pacific. “It’s massively important to know what to look for, and the fact that we are now able to test for this disease is going to be critical in advancing our ability to move forward with reintroductions and continuing the research,” notes Kim. “We’ve already been able to take fluid samples from all of our stars and get them analyzed for the presence of Vibrio pectenicida, so we’ve mobilized very quickly on the heels of development.” Paired with this new diagnostic clarity, advances in cryopreservation offer a second front in the effort to save the species. Frozen larvae can be stored for decades and offer flexibility for selective breeding of disease-tolerant traits, notes the team. Cryopreservation adds another tool to the scientists’ toolbox as they fight to prevent the species—and, in turn, its ecosystem—from wasting away. “Bringing back sunflower stars,” Bank says, “is the single-most important step we can take toward restoring kelp forest balance.” Get the latest Science stories in your inbox.

Archaeologists Are Unraveling the Mysteries Behind Deep Pits Found Near Stonehenge

Based on a comprehensive study, researchers are now convinced the shafts were human-made, likely dug during the Late Neolithic period roughly 4,000 years ago

Archaeologists Are Unraveling the Mysteries Behind Deep Pits Found Near Stonehenge Based on a comprehensive study, researchers are now convinced the shafts were human-made, likely dug during the Late Neolithic period roughly 4,000 years ago Sarah Kuta - Daily Correspondent December 10, 2025 9:59 a.m. The pits are evenly spaced around a large circle. University of Bradford In 2020, archaeologists in the United Kingdom made a surprising discovery. At Durrington Walls, a large Neolithic henge not far from Stonehenge, they found more than a dozen large, deep pits buried under layers of loose clay. The pits are mysterious. Each one measures roughly 30 feet wide by 15 feet deep, and together they form a mile-wide circle around Durrington Walls and neighboring Woodhenge. They also appear to be linked with the much older Larkhill causewayed enclosure, built more than 1,000 years before Durrington Walls. For the last few years, archaeologists have been puzzling over their origins: Were they dug intentionally by human hands? Were they naturally occurring structures, like sinkholes? Or is there some other possible explanation for the existence of these colossal shafts? Quick fact: The purpose of Durrington Walls While Stonehenge is thought to have been a sacred place for ceremonies, Durrington Walls was a place where people actually lived. In a new paper published in the journal Internet Archaeology, archaeologists report that they have a much better understanding of the pits’ purpose, chronology and environmental setting. And, now, they are confident the shafts were made by humans. “They can’t be occurring naturally,” says lead author Vincent Gaffney, an archaeologist at the University of Bradford, to the Guardian’s Steven Morris. “It just can’t happen. We think we’ve nailed it.” Chris Gaffney, an archaeologist at the at the University of Bradford, surveys the ground near Durrington Walls. University of Bradford For the study, researchers returned to the site in southern England and used several different methods to further analyze the unusual structures. They used a technique known as electrical resistance tomography to calculate the pits’ depths, and radar and magnetometry to suss out their shapes. They also took core samples of the sediment, then ran the soil through a variety of tests. For instance, they used optically stimulated luminescence to determine the last time each layer of soil had been exposed to the sun. They also looked for traces of animal or plant DNA. Astonishing' Stonehenge discovery offers new insights into Neolithic ancestors. Together, the results of these analyses indicate humans must have been involved, which suggests the pits could be “one of the largest prehistoric structures in Britain, if not the largest,” Gaffney tells the BBC’s Sophie Parker. Researchers suspect the circle pits were created by people living at the site over a short period of time during the Late Neolithic period roughly 4,000 years ago. They were not “simply dug and abandoned” but, rather, appear to have been part of a “structured, monumental landscape that speaks to the complexity and sophistication of Neolithic society,” Gaffney says in a statement. For example, the pits are fairly evenly spaced around the circle, which suggests their Neolithic creators were measuring the distances between them somehow. “The skill and effort that must have been required to not only dig the pits, but also to place them so precisely within the landscape is a marvel,” says study co-author Richard Bates, a geophysicist at the University of St Andrews, in a statement. “When you consider that the pits are spread over such a large distance, the fact they are located in a near perfect circular pattern is quite remarkable.” Researchers used multiple methods to investigate the pits at Durrington Walls. University of Bradford But who dug the pits? And, perhaps more importantly, why? Archaeologists are still trying to definitively answer those questions, but they suspect the shafts were created to serve as some sort of sacred boundary around Durrington Walls. Their creators may also have been trying to connect with the underworld, per the Guardian. “They’re inscribing something about their cosmology, their belief systems, into the earth itself in a very dramatic way,” Gaddney tells the BBC. Get the latest stories in your inbox every weekday.

Is red meat bad for you? Limited research robs us of a clear answer.

We’d all appreciate more definitive guidance. Eating a varied diet is a wise move while we wait.

Over and over, we ask the question: Is Food X good or bad for you? And, over and over, belief in the answer — whether it’s yes or no — is held with conviction totally out of proportion with the strength of the evidence.Today’s illustration: red meat. It has become one of the most-disputed issues in food. It’s so polarizing that some people decide to eat no meat at all, while others decide to eat only meat. It’s poison, or it’s the only true fuel.The latest salvo in the Meat Wars was kicked off by a new report that outlines the optimal diet for both people and planet. The EAT-Lancet Report comes down hard on red meat; its recommended daily intake is a mere 14 grams — that’s half an ounce.Read on, and the news gets worse: “Because intake of red meat is not essential and appears to be linearly related to higher total mortality and risks of other health outcomes in populations that have consumed it for many years, the optimal intake may be zero.”Note that word: “related.” It’s the source of the problem with the report and its recommendation.The EAT-Lancet report, by researchers from 17 countries, bases its recommendation solely on observational data. When you do that, meat comes out looking pretty bad. In study after study, people who report eating a lot of meat have worse health outcomes than people who eat little. Meat-eating correlates with increased risk of heart disease, some cancers and all-cause mortality.But, as always with observational research that attempts to connect the dots between diet and health, the key question is whether the meat itself, or something else associated with a meat-heavy lifestyle, is actually causing the bad outcomes.That’s a hard question to answer, but there are clues that people who eat a lot of meat are very different from people who eat a little.Let’s look at a study, published in JAMA Internal Medicine, cited by the EAT-Lancet report; it has a convenient demographic summary. According to it, people in the top one-fifth of meat eaters are different from people in the bottom fifth in a lot of important ways: They weigh more, they’re more likely to smoke, they’re not as well-educated, they get less exercise, and they report lower intakes of fruit, vegetables and fiber. On the plus side, they report drinking less alcohol. But other than that, we’re looking at a litany of markers for a lifestyle that’s not particularly health-conscious.So, to suss out whether it’s the meat that’s raising disease risk, you have to somehow correct for any of the differences on that list — and most of that information also comes from observational research, so even the confounders are confounded.Then there are the things you can’t correct for. Sleep quality, depression and screen time, for example, all correlate with some of the same diseases meat correlates with, but most studies have no information on those.All this confounding explains one of my all-time favorite findings from observational research. It comes from the same study the demographics came from (analyzed in a 2015 paper). Sure enough, the people who ate the most meat were more likely to die of cancer and heart disease, but they were also more likely to die in accidents. And the biggest difference came from the catchall category “all others,” which invariably includes causes of death that have nothing to do with meat.Basically, there’s a very simple problem with relying on observational research: People who eat a lot of meat are very different from people who eat less of it. The meat definitely isn’t causing the accidental deaths (unless, perhaps, they’re tragic backyard grill mishaps), and it isn’t causing at least some of the “all others” deaths, so we know that heavy and light meat-eaters are different in all kinds of ways.That’s where controlled trials come in.In a perfect world, we could figure this out by keeping a large group of people captive for a lifetime, feeding half of them meat, and seeing what happens. Okay, maybe that’s not a perfect world, but it would be the best solution to this particular problem.Instead, we have trials that are short-term (because of logistics and cost), and necessarily rely on markers for disease, rather than the disease itself. For that to be useful, you need a marker that’s a reliable indicator. For a lot of diseases — including cancer — those are hard to come by. For heart disease, we have a good one: low-density lipoprotein (LDL) cholesterol. So, most of the controlled trials of meat-eating focus on heart disease.If you spend some time reading those trials (and I did, so you don’t have to), you find that most of them show some increase in LDL cholesterol, although it’s generally small.A 2025 analysis of 44 controlled trials on meat found that the only ones showing positive cardiovascular outcomes had links to the meat industry, and even then, only about one in five came out positive. Of the independent studies, about three-quarters showed negative outcomes, and the remaining one-quarter was neutral.This isn’t surprising. Red meat contains saturated fat, and we have countless trials that demonstrate sat fat’s ability to raise LDL. But if the meat you eat is relatively lean, that effect is going to be small.The lesson here is that we don’t have a lot of good evidence on meat and health. The observational evidence is hopelessly confounded, and the evidence from clinical trials is woefully limited. There’s so much we simply don’t know. There may be other ways meat raises risk (leading to over-absorption of heme iron and stimulating the production of TMAO, or trimethylamine N-oxide), but there’s little definitive evidence for them. And, of course, there’s the question of what you eat instead. If you’re eating red meat instead of, say, instant ramen, that may be an improvement. If, instead, you’re cutting back on your lentils, not so much.As always, the single-most important thing to remember about nutrition is that what we know is absolutely dwarfed by what we don’t know. Which means that, if you’re making decisions based on what we do know, you could very well be wrong.So what’s an eater to do? Meat is a nutritious food. In fact, animal foods are the only natural sources of a vitamin we need — B12 — which is an indication that we evolved with meat and dairy as part of our diet. It’s very hard to know whether eating some lean meat leads to better outcomes than eating no meat, but I think some meat is a good hedge against all that uncertainty. (The ethical and environmental concerns are also important, but for today let’s focus on health.)But plant foods are also nutritious. And eating a wide variety of them is also a good hedge against uncertainty. Which means the carnivore diet — all meat, all the time! — is a pretty bad bet.Unfortunately, “uncertainty” is not a word that features prominently in the Meat Wars. Instead, we have an unappetizing combination of nastiness and sanctimony, with each camp convinced that the truth and the light are on their side.Not that this is a metaphor for our times or anything.

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