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...
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Babies, dogs, and the riddles of word learning
Many Minds
It's kind of astonishing, really, that kids ever learn words. Each one poses a little riddle. Does this sound string refer to a person? A category of things? Or maybe some other feature of the blooming, buzzing world? And yet word learning happens. In fact, we now know it begins earlier in infancy than we realized. And we now know, further, that dogs (or at least some dogs) understand words as well. So how does this happen? What do babies and dogs really know about words? And how might we go about figuring this all out? My guests today are and Dr. Claudia Fugazza. Elika is an Associate...
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The inner life of the hand
Many Minds
Newton saw in the human hand proof of the divine; Darwin saw a key to our species' success. Many others, too, have described the hand in hyperbolic terms, as a paragon of design, a cornerstone of human uniqueness, an engine of our achievements. But what makes the human hand so powerful? Is it the proportions of the fingers? Is it the opposability of the thumb? Or, could it be none of this? Could it be that the real power of our hands lies—not in the physical design—but elsewhere, out of sight? My guest today is . Matt is Professor of Cognitive Neuroscience at Birkbeck, University of...
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From the archive: The cuttlefish and its coat of many colors
Many Minds
Hi friends! We're skipping a beat to take care of some spring housekeeping tasks. We will be back in May! In the meanwhile, enjoy this listener favorite from our archives! ----- [originally aired April 30, 2025] We humans have a hard time becoming invisible. For better or worse, we're basically stuck with the skin and body we have; we’re pretty fixed in our color, our shape, our overall appearance. And so we're fascinated by creatures that aren't—creatures that morph to meet the moment, that can functionally disappear, that can shape-shift on a dime. And no creatures are more skilled,...
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Illuminating cave art
Many Minds
Deep in our past, in the dark depths of caves, our ancestors did something strange and beautiful. Working by firelight, some doodled little designs. Others made hand stencils. Some saw a bulge of rock, or a crack in the wall, and thought to turn it into a horse or a bison. Why did they make this art? What did it mean to them? Who were these artists? These questions are old—very old—but thanks to new methods and new interpretive frameworks, archaeologists are beginning to see them in a new light. My guest today is . Izzy is an archaeologist at Aarhus University in Denmark,...
info_outlineHi friends, we will be on hiatus for the fall. To tide you over, we’re putting up some favorite episodes from our archives. You may not be surprised to hear that the paper featured in this archive pick attracted a lot of attention. In the time since we first aired this episode, it prompted at least one direct critique, which then occasioned a reply by the authors.
Enjoy!
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You have a big brain. I have a big brain. We, as a species, have pretty big brains. But this wasn't always the case. Way back when, our brains were much smaller; then they went through a bit of growth spurt, one that lasted for a couple million years. This steady ballooning of brain size is one of the key themes of the human story. But then there's a late-breaking twist in that story—a kind of unexpected epilogue. You see, after our brains grew, they shrank. But when this shrinkage happened and—of course, why—have remained mysterious. My guest today is Jeremy DeSilva, a paleoanthropologist at Dartmouth College. He’s an expert on the evolution of the foot and ankle. But, it turns out the body is all connected, so he also thinks about brains and heads. In a recent paper, Jerry and his colleagues took up the mystery of human brain shrinkage. They first set out to establish more precisely when in our past this occurred. Using a large database of crania, spanning few million years, Jerry’s team was able to establish that this shrinkage event happened much more recently than previously thought—a mere 3000 years ago. Naturally, the next question was why? What happened around that time that could have possibly caused our brains to deflate? To answer this, Jerry and his collaborators turned to an unexpected source of insight: Ants. That’s right, ants. They argue that these ultrasocial critters may offer clues to why we might have suddenly dispensed with a chunk of brain about the size of a lemon. This is a really juicy paper and a super fun conversation, so we should just get to it. But I did want to mention: Jerry has a recent book from 2021 called First Steps that I whole-heartedly recommend. It’s about origins of upright walking in humans—which it turns out, is bound up with all kinds of other important aspects of being human. So definitely check that out!
Thanks folks—on to my chat with Dr. Jerry DeSilva. Enjoy!
The paper we discuss is available here. A transcript of this episode is available here.
Notes and links
3:00 – A podcast episode from the Leakey Foundation about the so-called “obstetrical dilemma.”
5:40 – A refresher for those who have trouble keeping their ‘cenes’ straight: the Pleistocene refers to the period from 2.58 million years ago to 11,700 years ago; immediately after that came the Holocene, which we are still in today.
7:00 – An article discussing the issue of unethical collections of human remains.
10:30 – The key figure form Dr. DeSilva’s paper—showing the changing “slopes” of brain size over time—is available here.
19:30 – The original article by Leslie Aiello and Peter Wheeler on the “expensive tissue hypothesis.” A more recent popular article on the hypothesis.
20:45 – An article by a major proponent of the social intelligence hypothesis, Dr. Robin Dunbar. A more critical review of the social intelligence hypothesis.
23:00 – A recent paper by Jeff Stibel and an older preprint by John Hawks evaluating the “body size” explanation of recent brain shrinkage.
24:00 – See our earlier episode on human self-domestication with Brian Hare.
29:00 – One of Dr. DeSilva’s collaborators on this research is Dr. James Traniello, who specializes in ants.
34:45 – An overview of the earliest history of writing.
37:20 – Dr. DeSilva’s book, First Steps, came out in 2021.
39:00 – A recent paper discussing the evolution of rotational birth in humans.
Dr. DeSilva recommends:
Kindred, by Rebecca Wragg Sykes (featured in an earlier episode!)
Origin, by Jennifer Raff
You can find Dr. DeSilva on Twitter.
Many Minds is a project of the Diverse Intelligences Summer Institute (DISI) (https://disi.org), 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 (https://www.mayhilldesigns.co.uk/). Our transcripts are created by Sarah Dopierala (https://sarahdopierala.wordpress.com/).
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