Island of the tool users
Many Minds
Tool use is rare in the animal kingdom—but maybe not as rare as we once thought. Since Jane Goodall famously observed a chimpanzee fishing for termites, many new examples of animals using tools have come to light. Birds using sticks to forage for grubs. Sea otters using rocks to smash open mussels. Digger wasps using stones to close off their burrows. But as these examples mount, so do the scientific questions. What is tool use, really? What different forms does it take? Does it always imply a high degree of intelligence? And perhaps the biggest question of all: Why do some creatures use...
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Cognitive offloading and its consequences
Many Minds
For thousands of years—maybe for as long as we've been human—we've offloaded our thinking. We've counted on our fingers. We've carved tallies into bone. We've invented a long series of tools to help us reason, remember, and manage information—tools like abacuses, calendars, writing systems, calculators, smartphones, and many, many more. So cognitive offloading is hardly new—but the questions around it seem newly urgent. As cognitive technologies accumulate, as opportunities for offloading tempt us at every turn, as headlines warn of "digital dementia" and "cognitive surrender," it...
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Coming of age in Ngogo
Many Minds
It's a familiar story in many ways. A child is born, and for years afterward is adored and indulged and anchored to home and family. But then the child grows up and starts crossing that long threshold into adulthood. The transition proves—to say the least—a bit turbulent. Now when I say this story is familiar, I don't just mean familiar to us as human beings. After all, a similar story has long played out among our closest cousins, the chimpanzees. My guest today is . Rachna co-directs the longstanding in Uganda and is an incoming Assistant Professor of Psychology at the University of...
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The natural history of linguistic diversity
Many Minds
Thousands of languages are used around the world today, and this linguistic diversity is a precious part of our human heritage. But it's also more than that. Linguistic diversity provides clues—a vast crazy quilt of clues—about how language works, about how history has unfolded, about the dynamics of culture, and about the nature of the human mind. My guest today is . Damián is an based at the at the Pompeu Fabra University in Barcelona. Over the last decade or so, Damián’s emerged as one of the most innovative researchers in the study of language and linguistic diversity. He’s...
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From the archive: Electric ecology
Many Minds
Hi friends! We're still taking a bit of a summer pause. We'll be back at the end of August—in the meanwhile, enjoy this listener favorite from our archives! ----- [originally aired September 19, 2024] There's a bit of a buzz out there, right now, but maybe you haven’t noticed. It's in the water, it's in the air. It's electricity—and it's all around us, all the time, including in some places you might not have expected to find it. We humans, after all, are not super tuned in to this layer of reality. But many other creatures are—and scientists are starting to take note. My guest today...
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From the archive: Varieties of childhood
Many Minds
Hi friends! We're taking a bit of a summer pause. We'll be back soon—in the meanwhile, enjoy this listener favorite from our archives! ----- [originally aired July 10, 2025] Childhood is a special time, a strange time. Children are adored and catered to—they're given their own menus and bedrooms. They're considered delicate and precious, and so we cushion them from every imaginable risk. Kids are encouraged to play, of course—but very often it's under the watchful eye of anxious adults. This, anyway, is how childhood looks in much of the United States today. But is this the way childhood...
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From the archive: Philosophers on psychedelics
Many Minds
Hi friends! We're taking a bit of a summer pause. We will be back soon—in the meanwhile, enjoy this listener favorite from our archives! ----- [originally aired May 14, 2025] Some call it the "psychedelic renaissance." In the last decade or so, interest in psychedelic drugs has surged—and not just among Silicon Valley types and psychiatrists and neuroscientists. It's also surged among a stereotypically soberer crowd: academic philosophers. The reasons are clear. With their varied and sometimes transformative effects, psychedelics raise ethical questions, epistemological questions,...
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The origins of Darwin's ideas
Many Minds
No discipline, no sphere of intellectual life, has been untouched by the work of Charles Darwin. He died in 1882 but his ideas are very much alive; they're now central to how we understand the natural world, the human mind, non-human minds, plants, biogeography, morality and emotion, culture, language, and more. But where did his ideas come from? How did they grow out of his travels, his social circle, his hobbies, his particular cast of mind? My guest today is . Janet is Professor Emerita at Harvard University in the department of the History of Science. She is perhaps best known for...
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The sparkling deep
Many Minds
It’s tempting to see bioluminescence as an oddity, one of those rare eccentricities of life on earth. And, on land, maybe that’s true. But our planet is mostly water, and out in the open ocean bioluminescence is utterly commonplace. Creatures of all shapes and sorts sparkle and glow, glitter and pulse. But what are these displays for? Why did they evolve? How did light become the currency of the deep? My guest today is . Sönke is a Distinguished Professor of Biology at Duke University, where he and his research group study the visual ecology of the ocean. He’s the author of...
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Is Man the Hunter just a myth?
Many Minds
There's a story about of our past that you know well. It goes like this: At some point earlier in human evolution, we started to hunt. Men in particular—perhaps channeling some deep-seated aggressive impulses—began to seek out big game. This new food source, this bonanza of calories, was what allowed our brains to expand. It changed our bodies and our societies and sent our species off on a whole new track. In short, Man the Hunter made us human. This story—told in different versions, with different points of emphasis—has circulated for decades. It's been debunked and revived, rejected...
info_outlineBrains are not cheap. It takes a lot of calories to run a brain, and the bigger your brain, the more calories it takes. So how is it that, over the last couple million years, the human brain tripled in size. How could we possibly have afforded that? Where did the extra calories come from? There's no shortage of suggestions out there. Some say it was meat; others say it was tubers; many say it was by mastering fire and learning to cook. But now there's a newer proposal on the table and—spoiler—it's a bit funky.
My guests today are Katherine Bryant, Postdoctoral Fellow at Aix-Marseille University, and Erin Hecht, Assistant Professor in the Department of Human Evolutionary Biology at Harvard. Katherine, Erin, and another colleague are the authors of a new paper titled 'Fermentation technology as a driver of human brain expansion.' In it, they argue that fermented foods could have provided the caloric boost that allowed our brains to expand.
Here, we talk about how the human body differs from the bodies of other great apes, not just in terms of our brains but also in terms of our bowels. We discuss the different mechanisms by which fermented foods provide nutritional benefits over unfermented foods. We consider how fermentation—which basically happens whether you want it to or not—would have been cognitively easier to harness than fire. Along the way, we touch on kiviaq, chicha, makgeolli, hákarl, natto, Limburger cheese, salt-rising bread, and other arguably delectable products of fermentation.
This is a fun one friends. But before we get to it: a friendly reminder about this summer's Diverse Intelligences Summer Institute. This a yearly event in St Andrews, Scotland; it features a rich program of lectures and events devoted to the study of cognition, mind, and intelligence in all its forms. If you have a taste for cross-disciplinary ferment and bubbly conversation, DISI may be for you. The application window is now open but is closing soon. You can find more info at DISI.org. That's D-I-S-I.org.
Alright, friends, on to my conversation with Erin Hecht and Katherine Bryant. Enjoy!
A transcript of this episode is available here.
Notes and links
3:00 – A popular science article about the “infectiously delicious confection” that is salt-rising bread. A recipe for the bread.
6:00 – An article about makgeolli, a Korean rice wine. An article about chicha, the traditional corn-based fermented beverage that has been banned in some places.
11:30 – An article about the role of the arcuate fasciculus in language processing. A recent paper by Dr. Bryant and colleagues comparing the arcuate in humans and chimpanzees.
12:30 – A recent article by Dr. Hecht and colleagues on the evolutionary neuroscience of domestication.
13:00 – For discussions of the encephalization quotient (aka EQ) and of human brain evolution, see our previous episodes here and here.
15:00 – The classic paper on the “expensive tissue hypothesis.”
22:00 – An article about the role of meat in human evolution; an article about the role of tubers. The cooking hypothesis is most strongly associated with Richard Wrangham and his book, Catching Fire.
26:00 – A recent article on evidence for the widespread control of fire in human groups by around 400,000 years ago.
31:30 – A paper on how fermenting cassava reduces its toxicity.
38:30 – There have been various claims in the ethnographic literature that the control of fire has been lost among small groups, such as in Tasmania. See footnote 2 in this article.
44:30 – A popular article about kiviaq.
45:00 – The article from the New Yorker, by Rebecca Mead, about the foodways of the Faroe Islands.
53:00 – For more discussion of the so-called drunken monkey hypothesis, see our previous episode about intoxication.
1:00:30 – A popular article about hákarl, which is fermented Greenland shark.
Recommendations
The Botany of Desire, by Michael Pollan
The Art of Fermentation, by Sandor Katz
Wild Fermentation, by Sandor Katz
“How humans evolved large brains,” by Karin Isler & Carel van Schaik
Many Minds is a project of the Diverse Intelligences Summer Institute, which is made possible by a generous grant from the Templeton World Charity Foundation to UCLA. It is hosted and produced by Kensy Cooperrider, with help from Assistant Producer Urte Laukaityte and with creative support from DISI Directors Erica Cartmill and Jacob Foster. Our artwork is by Ben Oldroyd. Our transcripts are created by Sarah Dopierala.
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