Untangling The Science of Octopus Arms

Summary

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Podcast Summary: Short Wave - "Untangling The Science of Octopus Arms"

Date: September 19, 2025
Hosts: Regina Barber, Rachel Carlson (NPR)
Guest: Ari Shapiro (All Things Considered)

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Episode Overview

In this lively, curiosity-driven episode, the hosts tackle three recent and fascinating discoveries in science: early universe "red dots" seen through the James Webb Space Telescope, how animal (and possibly human) brains fill in missing visual information, and the surprising behaviors of octopus arms. Listeners are treated to quick, insightful explanations, accessible analogies, and plenty of playful banter, making complex science both approachable and fun.

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Key Discussion Points & Insights

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1. Mysterious "Red Dots" in Space & Black Hole Evolution

Timestamps: 02:52 – 05:06

• Discovery: Astrophysicists using James Webb images from the early universe (about 500 million years after the Big Bang) noticed strange "red dots" that current models can't explain.
• Confusion: If these red dots are galaxies, they're much older than they should be for their spot in cosmic history. As Rachel quipped, "It would be like checking on your little kid and finding a fully grown adult." (03:32)
• Leading Theories: The most compelling model describes the objects as a new kind of black hole, surrounded by a dense cloud of gas—“like an atmosphere, but it's not a planet or a star” (Rachel Carlson, 03:59).
• Potential Implication: These findings might explain how black holes from the early universe rapidly grew into supermassive black holes—aligning with earlier proposals by Priya Natarajan and colleagues, but more research is needed.
• Quote:
  • "Any normal star or galaxy model or black hole model does not fit the data, essentially." (Rachel Carlson, 03:59)
  • “It means that this could be a stage in black hole growth that scientists have never seen before.” (Rachel Carlson, 04:25)

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2. How Brains Fill in Missing Visual Information

Timestamps: 05:06 – 07:24

• Phenomenon: The brain's remarkable ability to "see" objects or shapes even when parts are missing, as a survival mechanism and as the basis for illusions.
• Example & Humor: Using the Kanizsa illusion (three Pac-Man-like shapes implying a triangle):
  • Ari’s take: “It looks like three black Pac-Mans heading for a threesome towards each other.” (Ari Shapiro, 05:53)
  • Rachel: “A lot of people see a triangle when they look at it.” (06:01)
• Study Findings: Researchers pinpointed a special set of neurons in mice that respond specifically to the edges of illusory shapes—not just real ones.
• Broader Impact: Identifying this circuit may eventually help in studying and treating perception disorders like schizophrenia, autism, ADHD, and Alzheimer's.
• Limitations: The study is in mice—humans may process things differently, and “a mouse can't say whether they see the triangle or not.” (Regina Barber, 07:15)
• Quote:
  • “These were different neurons specifically activated by the edges of the illusion.” (Rachel Carlson, 06:36)

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3. The Wiggly World of Octopus Arms

Timestamps: 07:24 – 09:17

• Question: Do octopuses use specific arms for certain tasks?
• Approach: Scientists painstakingly analyzed wild octopus videos, tracking each arm’s use:
  • "To look at what each arm is doing at a specific point, you have to watch that video eight times." — field biologist Chelsea Bennis (07:48)
• Findings:
  • No strict specialization: All arms are capable of the same actions.
  • Strong Preferences: Octopuses generally favor front arms for exploring and back arms for moving around.
• Why it Matters: Observing wild behaviors validates lab findings and is key for application to real-world scenarios—like robotics.
• Broader Applications: Insights may inspire more advanced, flexible “soft robotics” for search and rescue or ocean exploration.
• Quote:
  • “They're really good at hiding. Just finding them is difficult. And then once you do find them, it's really hard to then ensure that you—the big hairless monkey covered in neoprene—is not, like, messing up their behavior.” —Kurt Onthank, octopus researcher (08:32)
  • “It could help us get inspiration for flexible or soft robotics, which she says could be helpful for things like search and recovery or even ocean exploration.” (Rachel Carlson, 08:55)

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Notable Quotes & Memorable Moments

• Playful banter:
  • Ari: “Eight times the fun.” (01:05)
  • Ari, about the Kanizsa illusion: "It looks like three black Pac-Mans heading for a threesome towards each other." (05:53)
  • On octopus terminology:
    • Ari: “They're not octopi.”
    • Regina/Rachel: “I think it's both, right?” (09:15-09:17)

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Important Segment Timestamps

• Intro & What’s Ahead: 00:32–01:08
• Red Dots/Black Hole Story: 02:52–05:06
• Brain & Visual Gaps Story: 05:06–07:24
• Octopus Arms Story: 07:24–09:17

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Tone & Language

• Conversational, witty, and accessible
• Frequent use of analogies and humor to make topics engaging
• Hosts and guest maintain an upbeat, inquisitive spirit throughout

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Takeaways

• Science is often puzzling and fun: Each story reveals how discoveries often lead to more questions, not just answers.
• Octopuses continue to amaze: Even after years of research, their behaviors have new secrets to tell—and may hold clues for future technology.
• The brain is a mystery machine: Understanding visual illusions in animals could one day help tackle complex human conditions.

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Interested listeners are invited to visit the show notes for additional resources, including octopus videos and further readings.

Transcript

[Ari Shapiro]

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[Regina Barber]

You're listening to Short Wave from npr. Hey, shortwavers.

[Rachel Carlson]

Regina Barber here and Rachel Carlson with.

[Regina Barber]

Our bi weekly science news roundup featuring the hosts of All Things Considered. And today we have the always fun Ari Shapiro. We're gonna miss you, Ari.

[Ari Shapiro]

Oh, I'm only always fun when I'm with you. It's a testament to your show.

[Regina Barber]

I love doing it.

[Ari Shapiro]

So I hear today you're gonna tell me about some mysterious red dots in space.

[Rachel Carlson]

Yeah. And how the brain might fil missing information.

[Regina Barber]

And lastly, you'll love this, Ari. The wiggly world of octopus arms.

[Ari Shapiro]

Eight times the fun.

[Rachel Carlson]

Exactly.

[Regina Barber]

All that on this episode of Short Wave, the science podcast from npr. This message comes from the Michael J. Fox Foundation. Did you know that every six minutes someone in the US Is diagnosed with Parkinson's? It's the fastest growing brain disease in the world. Chances are you or someone you know is impacted by Parkinson's. The Michael J. Fox foundation is on a mission to find a cure. Now is a critical time for Parkinson's research and your support will help drive progress toward a cure. Get involved today. Visit michaeljfox.org getinvolved.

[Ari Shapiro]

This message comes from NPR sponsor US Bank. With US Bank Business Essentials, you get more than just a bank. You get a dedicated partner that provides you a powerful combo of checking and card payment processing with quick access to the money you've earned, proving that there is nothing as powerful as the power of us. Visit usbank.com today to learn more. Member FDIC Copyright 2025 US bank this message comes from Ritual. What makes Ritual Vitamins different? Ritual vitamins are made with bioavailable, clinically studied key ingredients and a patented nutrient delivery system that aims to help your body use the nutrients you're getting. Ritual's essential multivitamins are made with you and your body in mind and backed by scientific research, filled with key ingredients as well as the essence of mint so you can enjoy taking your vitamins. Get 25% off your first purchase when you visit ritual.com NPR okay, to kick us off, tell me about These red dots in space, I'm imagining, like, intergalactic acne. What is it?

[Regina Barber]

Well, let's start at the beginning, Ari. The universe probably started with the Big.

[Ari Shapiro]

Bang at the very beginning.

[Regina Barber]

Very, very beginning. So, Ari, this story starts with images from the new James Webb Space Telescope of the very, very early universe. We're talking, like, 500 million years after the Big Bang, which, since the universe is 13.8 billion years old, that's basically less than 5% of the universe's life.

[Rachel Carlson]

So when scientists were looking far back into the dawn of the universe, they noticed these very strange red objects in these images of space. They debated whether the dots were big black holes or galaxies. But the weird thing was, if they were galaxies, they were much older than they should have been. It would be like checking on your.

[Ari Shapiro]

Little kid and finding a fully grown adult.

[Regina Barber]

That's Bing Jie Wang, an astrophysicist who is part of a team that published a study about one of these red dots in the journal Astronomy and Astrophysics last week.

[Ari Shapiro]

What does her team think these red dots are?

[Regina Barber]

So, long story short, Ari, we still don't know. They're all very different. They all have, like, different features. The lead author of that study, astrophysicists on a degree Grof, says that our existing models really just don't explain what's going on in this specific case.

[Rachel Carlson]

So any normal star or galaxy model or black hole model does not fit the data, essentially. So they needed a new model to explain this specific red dot's features. And the study's claiming this new model points to a new kind of black hole, one surrounded by a dense cloud of cooler gas, kind of like an atmosphere, but it's not a planet or a star.

[Ari Shapiro]

I didn't know black holes could have an atmosphere. What does that mean exactly?

[Rachel Carlson]

It means that this could be a stage in black hole growth that scientists have never seen before. It could also be a new clue as to how supermassive black holes at the centers of almost all galaxies are made. But astrophysicists aren't really sure.

[Ari Shapiro]

Do they have ideas about how that might work?

[Regina Barber]

Yeah. So I reached out to astrophysicist at Yale, Priya Natarajan, and she says this could be one example of how black holes rapidly grew into supermassive black holes. But that this is only one example of a model that she and her colleague Tella Alexander actually proposed a while ago. They thought that black holes created soon after the Big Bang with big clouds of dust and gas around them could rapidly grow to become supermassive. Black holes. So she thinks more work needs to be done.

[Ari Shapiro]

Okay, let's pivot from black holes to holes in information in the human brain. What's the second story?

[Rachel Carlson]

So the brain is wired to fill in visual gaps. For example, Ari, maybe an animal sees the tail of a lion hiding behind a bush, but their brain alerts them as if they've seen the entire lion.

[Ari Shapiro]

So, like, the brain fills in the gaps to say.

[Rachel Carlson]

Exactly. And in that case, that brain feature is really helpful. But sometimes in the case of things like optical illusions, the brain perceives objects that aren't actually there.

[Regina Barber]

And because of that, scientists can study illusions to try to understand how the brain fills in those gaps. A new study in Nature Neuroscience did exactly this in mice.

[Rachel Carlson]

So, Ari, I want you to look at an example of what the researchers showed the mice. It's called the Kaniza illusion. And tell me what you see.

[Ari Shapiro]

It looks like three black pac mans heading for a threesome towards each other.

[Rachel Carlson]

Okay. Honestly, I like that description. A lot of people see a triangle when they look at it.

[Ari Shapiro]

Oh, okay. Yeah. Cause, like, the gaps between the pac people's mouths makes a triangle. Yeah, got it.

[Rachel Carlson]

Yeah, exactly. So to a lot of people, it seems like there's a white triangle on top of those black pac men circle things.

[Regina Barber]

So this is an example of how the brain fills in the edges of a shape even when those edges don't exist. And when researchers at the University of California, Berkeley, and the Allen Institute in Seattle showed this image to mice, they found a special group of neurons in mice brains specifically involved in that process of filling in the missing edges.

[Rachel Carlson]

And researchers have known that the brain has neurons that respond to both the edges of real objects and the edges of illusions or objects that aren't really there, like that triangle. But these were different neurons specifically activated by the edges of the illusion.

[Ari Shapiro]

So what can researchers do with that information now that they've identified this, like, specific brain circuit?

[Rachel Carlson]

One of the study authors, Hae Young Shin, says with a lot more work, and, of course, work on humans, this could help researchers understand mental disorders that affect perception.

[Regina Barber]

The most famous example of that is.

[Rachel Carlson]

Schizophrenia, but also autism, adhd, Alzheimer's, many other diseases.

[Regina Barber]

Although one limitation of the study is that it's mice, A mouse can't say whether they see the triangle or not. So there's lots more to be done before we can make claims about humans.

[Ari Shapiro]

Okay, third story. Octopus arms. Take it away.

[Regina Barber]

Okay, Ari. So this new study came out in the journal Scientific Reports, and it's all about how octopuses Use different arms for different tasks.

[Rachel Carlson]

Scientists analyzed a bunch of videos of octopuses in the wild, and they were like, great. What's each individual arm doing here?

[Regina Barber]

Octopuses have eight arms, and to look at what each arm is doing at.

[Rachel Carlson]

A specific point, you have to watch that video eight times. That's Chelsea Bennis. She's a field biologist at Florida Atlantic University and a co author of the study.

[Ari Shapiro]

Sounds like a lot of octopus content to go through. What did they find?

[Rachel Carlson]

Two things. One, there was no arm specialization, meaning all of their arms were capable of doing all the same actions. But two, the octopuses still seem to prefer doing certain tasks with certain arms. The majority of the time, they use their front arms for exploration and their back arms for locomotion.

[Regina Barber]

Just to be clear, octopus researchers have observed some of these arm preferences in lab settings before. But Kurt Onthank, an octopus researcher at Walla Walla University in Washington state who's not affiliated with this research, says it's important for us to observe it in the wild, too.

[Ari Shapiro]

They're really good at hiding. Just finding them is difficult. And then once you do find them, it's really hard to then ensure that you. The big hairless monkey covered in neoprene is not, like, messing up their behavior. Huh. Okay, well, what do we get out of knowing that an octopus might use one arm to give a thumbs up and another to give a peace sign?

[Rachel Carlson]

Yeah. When we asked Chelsea, she told us that it could help us get inspiration for flexible or soft robotics, which she says could be helpful for things like search and recovery or even ocean exploration. And Ari, if you want to see some of the videos the researchers looked at, plus peek at some cute octopuses, we'll have that video online and in our show notes.

[Ari Shapiro]

They're not octopi.

[Regina Barber]

I think it's both, right?

[Rachel Carlson]

I think it's both.

[Ari Shapiro]

Anyway, regardless, I look forward to to watching.

[Regina Barber]

Ari. You are such a great science nerd and you are always welcome on our show. We're going to miss you.

[Rachel Carlson]

We'll miss you. We love having you on for now.

[Ari Shapiro]

I love nerding out with you. Thank you for enlightening me every week.

[Regina Barber]

Aw. You can hear more of Ari on consider this NPR's afternoon podcast about what the news means for you. This episode was produced by Hannah Chen and Jordan Marie Smith. It was edited by Burleigh McCoy and Patrick Jaranwattanan.

[Rachel Carlson]

Tyler Jones checked the facts. Tiffany Vera Castro and Patrick Murray were the audio engineers. I'm Rachel Carlson.

[Regina Barber]

And I'm Regina Barber. Thank you for listening. To Short Wave, the science podcast from npr.

[Ari Shapiro]

This is Eric Glass. On this American Life. We like stories that surprise you. For instance, imagine finding a new hobby and realizing to do this hobby right according to the ways of the masters. There's a pretty good chance that you're gonna have to bend the law to get the materials that you need, if not break it. Yeah, to break international laws. Your life stories, really good ones. This American Life.

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[Rachel Carlson]

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[Regina Barber]

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[Ari Shapiro]

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