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_outlineIt'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 Dr. Rachna Reddy. Rachna co-directs the longstanding Ngogo Chimpanzee Project in Uganda and is an incoming Assistant Professor of Psychology at the University of California, Berkeley. For more than a decade now, she has been closely observing the chimpanzees at Ngogo—and especially the adolescents.
Here Rachna and I talk about why adolescence—in all its intensity—is such a scientifically fascinating life-stage. We sketch the Ngogo research site, home to the largest group of chimpanzees ever studied. We unpack the different stages of chimpanzee life history. We zoom in on chimpanzee adolescence using a variety of different lenses—we talk about greetings, dominance hierarchies, grooming, social rejection, mentorship, deference, patrolling, female dispersal, and more. We discuss the so-called civil war that has taken root at Ngogo. And, finally, we talk about Rachna's in-progress novel (if that's the right word), which tells the story of one chimpanzee's coming of age in immersive detail.
I think you'll enjoy this one, folks. Chimpanzees offer us a kind of parallel universe, a funhouse mirror version of human life—one that is deeply relatable in some ways, and totally alien to us in others. And the parallels and non-parallels are arguably all the more striking in adolescence.
But before we get to it, one humble ask: As the new season of Many Minds ramps up, this would be a great time to support the show. You could do this by rating us, writing a review on Apple Podcasts or a comment on Spotify, or by doing the old-fashioned thing of just recommending us to a friend or colleague. Your support is—as always—much appreciated.
Alright friends, without further ado. Here's my conversation with Dr. Rachna Reddy. Enjoy!
Notes
4:00 – Damien and several other chimpanzees discussed in this episode feature in the Netflix documentary series Chimp Empire.
8:00 – See here for a study by Dr. Reddy and a colleague on caregiving behavior in recently orphaned chimpanzee siblings.
13:00 – See here for a comprehensive recent article by Dr. Reddy and colleagues about puberty and adolescence in chimpanzees.
16:00 – The Ngogo fission—and subsequent “civil war”—is treated in detail in Chimp Empire and was the subject of a recent, widely discussed research paper (which includes Dr. Reddy as an author).
26:00 – “Tanner stages” are a widely used scale for measuring different phases of puberty in humans.
29:00 – For more discussion of life history stages and how these differ across species, see our earlier episodes here and here. For a recent report that Ngogo females experience menopause, see here.
36:00 – For some of Dr. Reddy’s work on dominance hierarchies in adolescent male chimps, see here.
39:00 – For a detailed discussion of the chimpanzee “pant grunt” and its development, see here.
47:00 – For a study of female dispersal in a different chimpanzee population, see here.
54:00 – A video of a Tai chimpanzee playing “airplane” with her baby.
1:04:00 – A classic study of boundary patrolling at Ngogo.
1:11:00 – A study by Dr. Reddy and a colleague on sociosexual behavior in chimpanzees.
1:15:00 – A study by Dr. Reddy and a colleague on relationships between chimpanzee mothers and sons.
1:17:00 – A recent study conducted by Dr. Laura Simone Lewis (former guest!), Dr. Reddy, and others on social curiosity in chimpanzees and human children.
1:26:00 – For classic work by Jane Goodall featuring chimpanzee characters, see her 1971 book, In the Shadow of Man.
Recommendations
Work by Kazuya Toda in bonobos (e.g., here)
Work by Caitlin A. O'Connell in orangutans (e.g., here)
Work by Ella Brown in gorillas (e.g., here)
Tile art credit: Image of Jarman at age 11, courtesy of Rachna Reddy
Many Minds is a project of the Diverse Intelligences Summer Institute, which is made possible by a generous grant from the John Templeton Foundation to Indiana University. The show 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.
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