Why Do Some 80 Year-Olds Have Extraordinary Memories?

Summary

Short Wave: Why Do Some 80-Year-Olds Have Extraordinary Memories?

Released on August 8, 2025, by NPR's "Short Wave," this episode delves into the fascinating world of superagers, explores the resilience of endangered eagles in Japan, and uncovers mysterious life forms thriving in the deepest parts of our oceans. Hosted by Regina Barber and Rachel Carlson, with insights from guest Elsa Chang, the episode offers a rich tapestry of scientific discoveries and intriguing stories.

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1. Superagers: Unlocking the Secrets of Extraordinary Memory

Overview: The episode kicks off by exploring the phenomenon of "superagers"—individuals in their 80s who retain memory capabilities comparable to those in their 50s and 60s. This segment draws on 25 years of research from Northwestern University, as summarized in the journal Alzheimer's and Dementia.

Key Points:

• Social Engagement: Superagers consistently engage in meaningful social interactions. Regina Barber highlights, “[Superagers] all have consistent social interaction, strong social relationships, and meaningful interactions with other people” (02:57).

• Quality Sleep: Beyond mere hours of rest, the quality of sleep plays a crucial role. According to Dr. Sandra Weintraub, a clinical neuropsychologist at Northwestern University, “getting high quality sleep” is essential for maintaining cognitive functions (03:06).

• Physical Activity: Regular movement and exercise are also linked to maintaining memory, though these factors are harder to measure objectively (03:08).

• Genetics: Amanda Marr from the University of Michigan notes that while genetics contribute to superaging, they aren't the sole factor. “Lots of people have genetic risk factors for Alzheimer's disease or dementia, but don't show any signs of those conditions” (03:33).

• Neurological Factors: Superagers exhibit slower brain shrinkage and possess a higher count of Von Economo neurons, which are associated with social bonding and cognitive resilience (04:20).

Notable Quote: Sandra Weintraub emphasizes the variability among older adults, stating, “superagers offer insight into how we all might be able to keep our brains healthy as we age” (04:53).

Conclusion: Understanding superagers provides valuable clues about the interplay between behavioral and neurological factors in aging, offering pathways to enhance cognitive health for the broader population.

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2. The Resilient Eagles of Japan: Surviving Toxic Toads

Overview: The conversation shifts to the crescent serpent eagles in Japan, a critically endangered subspecies numbering around 200 individuals. These eagles have adapted to thrive despite feeding on introduced toxic cane toads.

Key Points:

• Invasive Species Challenge: Cane toads were introduced to Ishigaki Island in 1978 for pest control, inadvertently introducing a toxin that fatally affects many predators (05:25).

• Genetic Adaptation: Elisa Tobe from Kyoto University explains that these eagles possess a unique genetic adaptation allowing them to neutralize the toxins in cane toads. This adaptation dates back at least 10,000 years, preceding the introduction of the toads (05:58).

• Wider Evolutionary Significance: Evolutionary biologist Shabna Mohammadi points out that such adaptations are widespread across various species, indicating a common evolutionary strategy to cope with toxins (06:23).

• Conservation Implications: While the eagles' resilience is a beacon of hope, the invasive cane toads still pose a significant ecological threat. Efforts to remove these pests remain crucial to preserving the island's broader ecosystem (06:55).

Notable Quote: Shabna Mohammadi elaborates on the genetic adaptability, “This adaptation isn't unique to the eagles. It's actually very, very widespread” (06:29).

Conclusion: The survival of the crescent serpent eagles underscores the complexity of ecological interactions and the remarkable ways species adapt to human-induced environmental changes.

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3. Life in the Hadal Zone: Discovering Mysteries in the Deepest Oceans

Overview: The episode concludes with an exploration of the hadal zone, the deepest parts of the ocean, where life thrives in conditions previously thought inhospitable. This segment draws from a study published in Nature and insights from geochemist Meng Gren Du of the Chinese Academy of Sciences.

Key Points:

• Hadal Zone Characteristics: Named after the Greek god Hades, the hadal zone extends nearly six miles beneath the ocean surface, devoid of sunlight and marked by extreme pressure.

• Energy Sources: Contrary to long-held beliefs that life here relies solely on organic matter falling from above, recent research indicates that certain organisms derive energy from chemicals like hydrogen sulfide and methane seeping from the ocean floor (07:56).

• Unique Ecosystems: Meng Gren Du's expedition in a submersible revealed diverse life forms, including tubeworms, clams, and microbial mats near cold seeps. These organisms harness chemosynthesis, where microbes convert seeped chemicals into organic compounds that sustain the ecosystem (08:03).

• Future Research: The discovery of these ecosystems opens avenues for further exploration, with the potential to uncover myriad undiscovered species and understand the fundamental processes that enable life in such extreme environments (08:56).

Notable Quote: Rachel Carlson marvels at the exploration technology, saying, “submersible is like a time machine to me” (08:05), highlighting the awe-inspiring nature of deep-sea research.

Conclusion: The hadal zone remains one of Earth's final frontiers, with ongoing research promising to unveil the secrets of life in the planet's most extreme habitats.

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Final Thoughts

This episode of Short Wave masterfully weaves together stories of human cognitive resilience, evolutionary biology, and deep-sea ecology, illustrating the vast and varied avenues of scientific exploration. By highlighting both the resilience of individual species and the adaptability of life in extreme conditions, Regina Barber and Rachel Carlson provide listeners with a profound appreciation for the complexity and wonder of the natural world.

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Notable Contributors:

• Elsa Chang: Guest and co-host from All Things Considered
• Dr. Sandra Weintraub: Clinical Neuropsychologist, Northwestern University
• Amanda Marr: Clinical Neuropsychologist, University of Michigan
• Elisa Tobe: Lead Author, Kyoto University
• Shabna Mohammadi: Evolutionary Biologist

For more in-depth discussions and supporting research, listeners are encouraged to explore the referenced journals: Alzheimer's and Dementia, BMC Ecology and Evolution, and Nature.

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Timestamp Key:

• 02:57
• 03:06
• 03:08
• 03:33
• 04:20
• 04:53
• 05:25
• 05:58
• 06:23
• 06:29
• 06:55
• 07:56
• 08:03
• 08:05
• 08:56

Note: Timestamps correspond to the original podcast transcript for reference.

Transcript

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[NPR Host]

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

[Regina Barber]

Regina Barber here and Rachel Carlson with our bi weekly science news roundup featuring the hosts of All Things Considered. And today we have Elsa Chang. Hello, welcome.

[NPR Host]

Hello, West Coast.

[Regina Barber]

Representing Woo Hoo.

[Rachel Carlson]

And I heard we've got some new research on how some people are aging extra well. Hopefully including me, right?

[NPR Host]

Yeah, me too.

[Regina Barber]

Oh, yeah.

[NPR Host]

Plus, endangered eagles feeding on toxic toads without harm.

[Regina Barber]

And a new discovery about life in some of the deepest parts of the ocean.

[Rachel Carlson]

Fascinating. I love mysterious, mysterious deep sea stories.

[NPR Host]

Just like our whole, you know, summer series, sea Camp.

[Rachel Carlson]

That's right.

[NPR Host]

You're listening to Shortwave, the science podcast from NPR.

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[NPR Host]

Okay, Elsa, West Coast, Best coast. Where do we start?

[Rachel Carlson]

Okay, I definitely want to start with the people who age extraordinarily well. Super curious if we're talking about Asians. Rachel, kick us off.

[Regina Barber]

For 25 years, Northwestern University has studied these people who are in their 80s, but with the memory abilities of someone 50 to 60 years. They're called superagers. And this week in the journal Alzheimer's and Dementia, researchers summarize some of the secrets superagers seem to have in common.

[Rachel Carlson]

I Want to be a super ager? What's their secret? Tell us.

[Regina Barber]

One commonality between superagers is they all have consistent social interaction, strong social relationships, and meaningful interactions with other people.

[Rachel Carlson]

Okay, so keep partying. Go ahead.

[NPR Host]

Other factors may include getting good sleep, not just like, being asleep for enough time, but getting high quality sleep. A clinical clinical neuropsychologist at Northwestern University, Dr. Sandra Weintraub, says movement and exercise may also play a key role, but those are more difficult to study objectively.

[Rachel Carlson]

Okay, I feel like I'm screwed on sleep, but I have a social interaction piece down. What about genetics?

[Regina Barber]

I asked another researcher who wasn't involved in the paper, Amanda Marr. She's a clinical neuropsychologist at the University of Michigan. And she told me genetics do play a role in super aging. Surprise. But they're not the whole picture. Lots of people have genetic risk factors for Alzheimer's disease or dementia, but don't show any signs of those conditions.

[NPR Host]

So the question is, what helps those people's brains resist those conditions?

[Rachel Carlson]

Yeah. Do they have any ideas from this research?

[NPR Host]

Yeah, those two things we already mentioned, like social interaction and sleep probably play a role also. We know that the human brain tends to slow down as we age. Like, even healthy brains shrink, which can make learning and memory harder as people age. But superagers brains shrink more slowly than brains of their peers, and researchers think that that's involved in avoiding cognitive decline.

[Regina Barber]

Superagers also have a lot of this particular type of neuron compared to other people their age. It's called the Von Economo neuron, and it's a big neuron found in humans and some other species like whales and elephants. And researchers think it's related to social relationships or social bonding.

[NPR Host]

And everyone we spoke to said these are all clues to help understand how those behavioral elements and neurological elements are connected to one another. Here's Sandra Reintraub again.

[BetterHelp]

Just because you're getting older doesn't mean you're losing it.

[Rachel Carlson]

I think we assume, oh, you know.

[BetterHelp]

They'Re just getting older, they're forgetful. That's not true.

[Regina Barber]

Sandra says there's a lot of variability amongst older people and that superagers offer insight into how we all might be able to keep our brains healthy as we age.

[Rachel Carlson]

Oh, I want that. Okay, so we go from superagers to eagles in Japan. They are somehow eating toxic toads and still doing okay. What?

[NPR Host]

Yeah, that's right. So these are the crescent serpent eagles, which are, are critically endangered in Japan. A subspecies of these eagles live on two small islands there, and there are only about 200 of them.

[Regina Barber]

And in 1978, cane toads from Central and South America were introduced to one of the islands, Ishigaki. The goal was pest control to get rid of the bugs eating the cane sugar crops. But the toads are toxic, so predators who fed on them started dying, too.

[Rachel Carlson]

But the eagles are totally fine.

[NPR Host]

Yeah. So a new study documents the fact that the they've been feeding on the toads for almost 50 years with no visible symptoms from the cane toad's toxins. The question is how? Like I asked Elisa Tobe at Kyoto University about that. She's the lead author of a recent study in the journal BMC Ecology and Evolution. She got blood and tissue samples from these eagles on both islands and compared them to other raptors. And she found that the eagles have a special genetic adaptation to evade these toxins. An added patient that Alisa says they've had for at least 10,000 years, long before the cane toad showed up on the island.

[Regina Barber]

So by chance, they can feed on them.

[Rachel Carlson]

That's so cool. Is there any idea why they even have this adaptation at all?

[Regina Barber]

It turns out it's a somewhat common adaptation. We talked with evolutionary biologist Shabna Mohammadi about this.

[NPR Host]

This adaptation isn't unique to the eagles. It's actually very, very widespread. And what we found in rodents, in frogs, in snakes, many predators, sometimes they've gained this adaptation and they still have it today, even though they don't need it.

[Rachel Carlson]

Okay, but what's the upshot? Like, is this good news for this endangered species?

[Regina Barber]

Yes and no. So some people have argued we should keep these cane toads for the eagles to feed on, since they aren't harmed. But keep in mind these toads are an invasive species, A human induced ecological disaster, and haven't been good for the environment. On Ishigaki, many animals die of heart attacks if they eat them. So Elisa's still in favor of removing the invasive pest.

[NPR Host]

On the plus side, Shabnam says understanding this adaptation can tell us much more about evolution. Like when species so distantly related can have gene sequences that can do the same thing.

[Rachel Carlson]

That's so cool. Okay, last topic. Life in the deep ocean. Rachel, what's going on down there?

[Regina Barber]

We're talking about the hadal zone, Elsa. It's the deepest part of the ocean, Named for the Greek God of the underworld, Hades.

[Rachel Carlson]

Oh, I get it. Okay, yeah.

[Regina Barber]

If you could have imagine based on that name. Life is pretty hard down there. No sunlight reaches down this far and.

[NPR Host]

For a long time, researchers thought that life in this zone mostly ate like organic matter falling from the ocean surface. Like bits of dead animals. Like poop.

[Rachel Carlson]

Yum.

[NPR Host]

But now a study in the journal Nature suggests that these deep sea creatures may also get some energy from chemicals seeping out of the ocean floor.

[Rachel Carlson]

Ooh. How does that work?

[NPR Host]

So I talked to Meng Gren Du. She's a geochemist at the Chinese Academy of Sciences. And to study all this, she took this incredible journey down nearly six miles under the ocean surface in a submersible. And she landed in two trenches in the northwest Pacific Ocean near Japan and Russia. So submersible is like a time machine to me. So whenever I dive to a new ocean somewhere, it always open a new world for me.

[Regina Barber]

During her aquatic time travel, she found tubeworms, clams, and microbial mats living near cold seeps. Those are places where chemicals like hydrogen sulfide and methane seep out of the ocean floor.

[Rachel Carlson]

Ew. Wait, how do these sea creatures survive on that?

[Regina Barber]

The researchers think that microbes inside of the animals use those chemicals to make organic compounds. Then the animals feed off of those compounds.

[NPR Host]

Yeah, and the next step is exploring, like, more trenches at this depth. Now that we know that there's so much life down there, Mangren thinks that there are many more species to discover and more to learn about how life works there.

[Rachel Carlson]

Yeah, but she has to get in a submersible. Not for me.

[NPR Host]

No way. She loved it. She said it was amazing.

[Rachel Carlson]

Okay, good for her.

[Regina Barber]

But if you come back, we won't make you get in one.

[Rachel Carlson]

No, it'll never happen.

[NPR Host]

No. You can hear more of Elsa on consider this NPR's afternoon podcast about what the news means for you.

[Regina Barber]

This episode was produced by me, Rachel Carlson, and Michelle Aslam. It was edited by Rebecca Ramirez and Christopher Intel.

[NPR Host]

Yotta Tyler Jones checked the facts. Ted Meadbane and Gilly Moon were the audio engineers. I'm Regina Barber.

[Regina Barber]

And I'm Rachel Carlson. Thanks for listening to Shortwave, the Science podcast from NPR.

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