Many Minds

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, more astonishing, more bedazzling in their abilities to do this kind of thing than the cephalopods. But how do they do this exactly? What's going on in their skin? What's going on under their skin? And what's going on in their brains that makes this all possible? My guest today is Dr. Tessa Montague. Tessa is a neuroscientist in the Axel Lab at Columbia University; she studies the brain and behavior of the dwarf cuttlefish, with a special focus on the biology of their dynamic skin behaviors. Here, Tessa and I talk about how cuttlefish and other cephalopods exhibit the most impressive camouflaging abilities on the planet. We discuss how they change their skin's appearance with remarkable speed and fidelity—and not just when trying to blend in, but also when hunting, courting, fighting, and more. We talk about whether these behaviors are flexible and whether they're voluntary. We linger on the cruel irony that cuttlefish seem to be colorblind. We talk about the idea that a cephalopod's skin is kind of a window into their brain. We lay out the cells and organs in the cephalopod skin the make these behaviors possible—especially the tiny pigment-bearing structures called "chromatophores." And of course we also dive deep into the cephalopod brain and its sometimes bizarre and poorly understood structures. Excited to share it with you friends—I think you'll enjoy it. Without further ado, here's my chat with Dr. Tessa Montague.   A transcript of this episode will be posted soon.   Notes and links 3:00 – For more on Dr. Montague’s recent expeditions to the Philippines, including photos, see here. 7:30 – Dr. Montague has published two recent reviews of dynamic skin behaviors in cephalopods—see here and here. We previously discussed cephalopod intelligence in a 2021 episode with Dr. Alex Schnell and a 2023 episode with the novelist Ray Nayler. 18:30 – For discussion of a recent “renaissance” in new model organisms, see here. 20:30 – For more on how chameleons change color, see this video. 25:00 – A video primer on cuttlefish camouflage, featuring the researcher Dr. Robert Hanlon. 30:30 – A recent paper on the details of pattern matching in cuttlefish camouflage. 31:00 – For more on the mimicking plant Boquila trifoliolata, see this popular article. See also our earlier episode with Dr. Paco Calvo and Dr. Natalie Lawrence. 35:00 – A video about the so-called mimic octopus.  40:00 – For the hypothesis about color discrimination via chromatic aberration and pupil shape, see here. 44:00 – For more on the “split body” skin behaviors observed in some cuttlefish, see here. 51:00 – For the David Attenborough clip about a cuttlefish hypnotizing a crab, see here. For the recent New York Times article on cuttlefish hunting behavior, including videos, see here. For the academic article that inspired the New York Times piece, see here. 58:00 – A recent scientific study on the possibility of octopus skin activity during dreaming. A video that helped popularize the idea of cephalopod skin activity as evidence of dreaming. Our earlier episode on why we—and other creatures—dream. 1:06:00 – For a study on chromatophore development from the lab of Dr. Gilles Laurent, see here. 1:11:00 – For more on papillae, including videos, see here.  1:17:00 – To explore an animated model of the cuttlefish brain, see this page of Dr. Montague’s website, Cuttlebase.   Recommendations Monarchs of the Sea, Danna Staaf Other Minds, Peter Godfrey-Smith Cephalopod Behavior, Roger Hanlon & John B. Messenger   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. Our transcripts are created by Sarah Dopierala. Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].    For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

You've probably come across the "free energy principle." It's become one of the most influential ideas in the broader cognitive sciences. Since the neuroscientist Karl Friston first introduced it in 2005, the theory has been fleshed out, extended, generalized, criticized, and cited thousands and thousands of times. But what is this idea, exactly? What does it say about the nature of brains and minds? What does it say about the phenomenon of life itself? And is anything that it says really that new? My guest today is Dr. Kate Nave. Kate is a philosopher at the University of Edinburgh and the author of the new book, A Drive to Survive: The Free Energy Principle and the Meaning of Life. In the book, Kate offers an extended critical analysis of the free energy principle and situates it in a broader landscape of ideas about the nature of life and mind. In this conversation, Kate and I talk about how the free energy principle has changed over time, from its beginnings as a theory of cortical responses in the brain to its eventual status as a theory of... well, a lot. We discuss why this theory has had such an enormous influence, and we talk about how many of the key ideas behind it actually have a long history. We consider some kindred spirits of the free energy framework— approaches like cybernetics, enactivism, predictive processing, and autopoiesis. We walk through a series of questions that all these approaches have long grappled with. Questions like: What does it mean to be alive? What is the relationship between being alive and being cognitive? What are the roles of prediction and representation in cognition? And we ask how—if it all—the free energy principle gives us new answers to these old questions. Along the way, Kate and I touch on: surprisal, visual phenomenology, vitalism, Husserl and Merleau-Ponty, Maturana and Varela, pendulums and bacteria, computation and models, primordial purposiveness, pancakes, and whether we'll ever be able to create artificial life. As you might be able to tell from the description I just gave, this conversation goes pretty deep—and it does get a bit technical. It dives down into the history and philosophy around some of the most foundational questions we can ask about minds. If that sounds like your cup of tea, enjoy. Alright friends, on to my conversation with Dr. Kate Nave!   A transcript of this episode is available here.   Notes and links 5:00 – The 2005 paper in which Karl Friston proposed the principle of free energy minimization. Friston later generalized the ideas here and here. 14:00 – For influential philosophical work on action in perception, see Alva Nöe’s book, Action in Perception. 17:00 – One of the classic works in the “enactivist” tradition is Evan Thompson’s book, Mind in Life. 18:00 – The actual quip, credited to Carl Sagan, is about “apple pie” not pancakes: “If you wish to make an apple pie from scratch, you must first invent the universe.” 20:00 – The notion of “autopoiesis” (or “self-creation”) was introduced by Humberto Maturana and Francisco Varela in their book, Autopoiesis and Cognition. 24:00 – A classic paper of cybernetics from 1943, ‘Behavior, purpose, and teleology.’ 37:00 – For more on the idea of “predictive processing,” see our earlier episode with Dr. Mark Miller. 43:00 – For a discussion of the idea of “representation” in the philosophy of cognitive science, see here. For a discussion of “anti-representationalism,” see here.   Recommendations ‘Organisms, Machines, and Thunderstorms: A History of Self-Organization,’ (part 1) (part 2), Evelyn Fox Keller The Mechanization of the Mind, Jean-Pierre Dupuy ‘The Reflex Machine and the Cybernetic Brain,’ M. Chirimuuta   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. Our transcripts are created by Sarah Dopierala. Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].    For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

Are human emotions universal? Or do they vary from one place to the next and from one time period to the next? It's a big question, an old question. And every discipline that's grappled with it brings its own take, its own framings and forms of evidence. Some researchers appeal to cross-cultural experiments; others turn to neuroimaging studies or conceptual analysis. Some even look to fiction. My guest today is Dr. Bradley Irish, an Associate Professor of English Literature at Arizona State University. Brad is the author of a new book, The Universality of Emotion: Perspectives from the Sciences and Humanities; in it he maps the landscape of debate around this long-contested topic. Brad is also the author of numerous articles and books on the emotions in Shakespeare's plays, as well as in the work of other early modern authors. Here, Brad and I talk about both sides of his work—his writing as an observer of cross-disciplinary debates about the universality of emotion and his writing as a scholar of literature. We sketch four prominent theories of emotions—basic emotions theory, appraisal theories, psychological construction theories, and social construction theories. We weigh the idea that some emotions are more universal than others. We talk about the role that language might play in our emotional experience. And we consider why many literary scholars tend to be deeply suspicious of claims about human universality. Along the way, Brad and I also touch on: the theory of ur-emotions, the aims of literary analysis; disgust, anger, schadenfreude, anxiety; frogs and public dissections; Shakespeare as a supposedly universal poet; and Brad's latest project on neurodiversity in literature. If you're enjoying the show, we would be most grateful if you could give us a rating or review, maybe even a shout-out on your social media platform of choice. For those who listen on Spotify, you can also now leave comments on individual episodes—which is a great way to let us know what you think. Alright friends, on to my conversation with Brad Irish. Enjoy! A transcript of this episode is available here.    Notes and links 7:00 – For an example of an anti-universalist treatment from a literary scholar, see here. See also Dr. Irish’s brief essay on the idea of universality in literary studies. 12:00 – For Dr. Irish’s first book—on emotions in the early modern period—see here.  15:00 – For a recent review/update of the “basic emotions theory” tradition, see here.  21:00 – An influential early paper on facial expressions of emotion across cultures. A more recent, critical perspective on the relationship between facial expressions and emotions.  23:00 – For a review of social constructionist approaches to emotion, see here. 24:00 – A recent review of the “appraisal theories” of emotion. 26:00 – Psychological constructionist theories of emotion are most strongly associated with the work of Dr. Lisa Feldman Barrett and colleagues. For an articulation of these views, see here. 33:00 – For more on the relationship between language and emotion, see influential recent studies here, here, and here.  39:00 – The paper introducing the concept of “ur-emotions.” 44:00 – Dr. Patrick Colm Hogan’s book, What Literature Teaches Us about Emotion. 49:00 – Dr. Irish’s book, Shakespeare & Disgust: The History and Science of Early Modern Revulsion. 58:00 – For an influential paper on disgust in general, see here. For more on moral disgust in particular, see here. 1:07:00 – For the idea that disgust evolved to help us avoid disease, see here. 1:15:00 – For more on the idea that fictions can be thought of as simulations of psychology and the social world, see our earlier episode on stories. 1:16:00 – For more about Dr. Irish’s latest research project, see his new book, Literary Neurodiversity Studies.   Recommendations Emotion Theory: The Routledge Comprehensive Guide, edited by Andrea Scarantino   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. Our transcripts are created by Sarah Dopierala. Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].  For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

Hi friends, We're taking care of some spring cleaning this week. We'll be back in two weeks with a new episode. In the meantime, enjoy this favorite from our archives! - The Many Minds team ––––––––– [originally aired February 22, 2024] Brains 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 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. Our transcripts are created by Sarah Dopierala. Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].  For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

The tree of life is a noisy place. From one branch come hoots and howls, from another come clicks and buzzes and whines. And coming from all over you hear the swell of song. But what is all this ruckus about? Why do so many animals communicate with sound? What kinds of meaning do these sounds convey? And—beyond the case of human speech—do any of these sounds merit the label of “language”? My guest today is Dr. Arik Kershenbaum, a zoologist at Cambridge University. Arik is an expert on vocal communication across the animal kingdom and the author of the recent book Why animals talk: The new science of animal communication. Here, Arik and I talk about why the acoustic medium is a popular choice for complex communication. We sketch a key difference between forms of communication that are purely expressive and forms that are also referential. We discuss, in turn, Arik's field research on wolves, hyraxes, and gibbons—and talk about what makes each of these animals such a revealing case study. We evaluate our prospects for quote unquote "translating" different kinds of animal communication, and we speculate about what communication systems could look like on other planets. Along the way, Arik and I touch on: noisy versus tonal sounds; short-range versus long-range communication; chorusing and duetting; simplicity and complexity; syntax and meaning; entropy; alarm calls; dolphins, orcas, and cuttlefish; and how you can tell that wolves take a certain pleasure in howling. Without further ado, here’s my chat with Dr. Arik Kershenbaum.   A transcript of this episode is available here.    Notes and links 6:30 – In the human case, of course, our most elaborated form of communication—language—comes in both spoken and signed forms. For more on the different modalities of human language, see, e.g., our earlier episode with Dr. Neil Cohn. 7:30 – The distinction between expressive and referential communication is perhaps most strongly associated with the linguist Roman Jakobson—see, for instance, this essay. For more on the question of whether animal communication systems involve reference, see this recent (philosophical) discussion. 9:00 – For a classic example of work on predator alarm calls in vervet monkeys, see here.  13:00 – For an example of Dr. Kershenbaum’s work on wolf (and other canid) howls, see here. The study provides evidence for howling “dialects.”  24:30 – An example of coyote chorusing can be heard here. 27:00 – A study showing that human listeners overestimate the size of a coyote group. 29:00 – For an example of Dr. Kershenbaum’s work on hyrax song, see here. An example of hyrax song can be heard here.  34:00 – For a primer on syntax in animal acoustic communication, see here.  40:00 – Examples of gibbon song can be heard here and here.  45:00 – For a paper on the syntax and complexity of gibbon songs, see here.  48:30 – A paper by Dr. Kershenbaum and colleagues on entropy and Zipf’s law in animal communication.  57:30 – A paper on Darwin’s theory of “musical protolanguage.” 59:30 – An example of research on orca communication.  1:00:00 – For more about Project CETI, see here.  1:07:00 – See Dr. Kershenbaum’s other book, The Zoologist’s Guide to the Galaxy.    Recommendations The Reign of Wolf 21, by Rick McIntyre Through a window, by Jane Goodall   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. Our transcripts are created by Sarah Dopierala. Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].  For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

Evolution is not what it used to be. A lot has changed since Darwin's day. In the first half of the 20th century, evolutionary theory was integrated with an emerging understanding of genetics. Late in the 20th century, biologists started taking seriously the idea that organisms don't just adapt to their environments, they change them. Recently, researchers have started to acknowledge the role of culture in evolutionary processes. And so slowly our understanding of evolution has been reconsidered, updated, expanded. And more updates are underway. But it's not just our understanding of evolution that has changed over time. Evolution itself has changed, too. My guest today is Dr. Kevin Lala. Kevin is an evolutionary biologist at the University of St Andrews in Scotland. Over his long career, Kevin has been at the forefront of key debates about—and updates to—evolutionary theory. He's known, for instance, for his pioneering work on niche construction as well as for his work on gene-culture co-evolution. In a new book titled Evolution Evolving, Kevin and his four co-authors present a new synthesis of evolution, one that places developmental processes front and center. Here, Kevin and I sketch the notion of a "developmental bias" and why it's central to this new understanding of evolution. We talk about the orthodox gene-centric way of thinking about development—and what it gets wrong. We discuss so-called exploratory processes in development. We dig into the increasingly popular, but much debated construct of "evolvability." And we consider what this newest update to evolutionary theory might tell us about the origins of human cognition. Along the way, Kevin and I talk about floppy ears in mammals and fragmented faces in fish; symbionts and soft inheritance; Mary Jane West-Eberhard, Richard Lewontin, and August Weismann; development as an artist and evolution as curator; maps; plants; manual dexterity; brain size; and why evolution is a bit like walking on a trampoline. A final reminder about the 2025 Diverse Intelligences Summer Institute, or DISI. DISI is a three-week long summer institute held in St Andrews, Scotland; it's a place for the wide-ranging, transdisciplinary exploration of ideas about mind, cognition, and intelligence. It's a place where early career scholars get to hobnob with thinkers like Kevin Lala, who was a faculty member with us in 2019. There's still time to apply, but do act fast—review of applications begins March 1st.   Alright friends, on to my conversation with Dr. Kevin Lala. Enjoy!   A transcript of this episode is available here.   Notes and links 4:00 – A paper describing so-called domestication syndrome. For more on domestication (and self-domestication), see our earlier episode with Dr. Brian Hare. 11:00 – A paper describing cavefish as a new model organism in the study of evolution and development. 15:00 – An influential 2015 paper, led by Dr. Lala, describing the “extended evolutionary synthesis.” 22:00 – A 2016 overview of niche construction theory, led by Dr. Lala. 27:00 – An early report on “lobtail feeding” in humpback whales. 33:00 – A paper describing “gaping behavior” in cichlid fishes. 35:00 – A review of “soft inheritance.” The study showing that mice pass on learned associations to offspring. 41:00 – A study on the gut microbes that allow woodrats to digest toxic creosote. 44:00 – See our earlier episode with Dr. Eric Turkheimer. 50:00 – See Winther’s book, When Maps Become the World. 56:00 – A paper reviewing the idea of “exploratory mechanisms” in development, as well as other ideas associated with the concept of “plasticity-led evolution.” 1:05:00 – A classic paper on the notion of “evolvability.” 1:13:00 – For one example of a “major transitions” framework, see our earlier episode with Dr. Andrew Barron. 1:17:00 – A news article about how dogs developed the ability to digest starch, initially by acquiring symbionts. 1:20:00 – For discussion of the evolution of human brain size, see our earlier episode ‘Fermentation, fire, and our big brains.’ 1:28:00 – A recent review of the idea that humans are “self-domesticated.”   Recommendations Developmental Plasticity and Evolution, by Mary Jane West-Eberhard   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. Our transcripts are created by Sarah Dopierala. Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].  For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

Where would our species be without string? It's one of our most basic technologies—so basic that it's easy to overlook. But humans have used string—and its cousins rope, yarn, cordage, thread, etc.—for all kinds of purposes, stretching back tens of thousands of years. We've used it for knots and textiles and fishing nets and carrier bags and bow-strings and record-keeping devices. It's one of the most ubiquitous, flexible, and useful technologies we have. But we haven't only put string to practical purposes. We've also long used it to tickle our minds. My guest today is Dr. Roope Kaaronen. Roope is a cognitive anthropologist and postdoc at the University of Helsinki in Finland. Along with an interdisciplinary team, Roope recently conducted two studies that showcase the centrality of string in human culture. One is on the history and diversity of "string figures” (which are visual designs made with a loop of string held between the hands, often known to English speakers as “Cat's Cradle”). The other study is on the history and diversity of knots. Here Roope and I discuss the deep history of string in human culture. We talk about the seemingly universal spread of string figures across the globe. We zoom in on one string figure in particular—the Jacob's ladder—which seems to be the most widespread string figure of all, despite its complexity. We talk about how both knots and string figures are related to the branch of mathematics known as “topology," and about how knots and string figures have evolved under different constraints. Finally, we discuss what our fascination with string designs might tell us about the human mind. And we lament the fact that much of our string-based cultural heritage is headed—quite rapidly—for extinction. Just a reminder that applications are now open for the 2025 Diverse Intelligences Summer Institute or DISI. If you are an early career researcher and you like this show, you would probably like DISI. Actually, fun fact: our guest today, Roope, is a DISI alum. We met at the Institute a couple years ago and I've followed his work ever since. That should give you some flavor for the people who attend. In any case, for more info, check out disi.org—that’s d-i-s-i. org. Alright friends, on to my conversation with Dr. Roope Kaaronen. Enjoy!   A transcript of this episode is available here.   Notes and links 3:00 – The 2020 paper reporting the use of string by Neanderthals. 8:00 – A paper describing the Antrea Net and its discovery. 10:00 – On the issue of gender bias in the study of textiles, see Virginia Postrel’s book, The Fabric of Civilization. 12:00 – Dr. Kaaronen’s other ethnomathematical projects include work on measurement across cultures.  16:30 – The website of the International String Figure Association. 19:30 – The 1969 paper first introducing the Standard Cross-Cultural Sample.  22:20 – A step-by-step explanation for how to make Jacob’s Ladder. 30:30 – A step-by-step explanation for how to make the Swan. 38:00 – An example of a string figure that uses the Caroline Extension.  40:35 – A video demonstrating the string figure game of Cat’s Cradle, which is played with a partner. 44:30 – A preprint of the knot study by Dr. Kaaronen and colleagues.  45:00 – The website of HRAF—the Human Relations Area Files—is here. 49:00 – A step-by-step explanation for how to make the knot known as the “sheet bend.” 55:00 – An interactive article about what is known about Incan khipus.  59:30 – The “bible of knots” is the Ashley Book of Knots. 1:08:30 – An illustrated article on the so-called Austronesian expansion. 1:16:00 – An image of the ochre stone from 70,000 years ago, found at Blombos cave, featuring net-like imagery. A study finding sensitivity to abstract shapes in humans but not baboons.   Recommendations The Fabric of Civilization, by Virginia Postrel String Figures: A Study of Cat’s Cradle in Many Lands, by Caroline Furness Jayne WhyKnot (YouTube channel)   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. Our transcripts are created by Sarah Dopierala. Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].  For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

Neurons have long enjoyed a kind of rock star status. We think of them as the most fundamental units of the brain—the active cells at the heart of brain function and, ultimately, at the heart of behavior, learning, and more. But neurons are only part of the story—about half the story, it turns out. The other half of the brain is made up of cells called glia. Glia were long thought to be important structurally but not particularly exciting—basically stage-hands there to support the work of the neurons. But in recent decades, at least among neuroscientists, that view has faded. In our understanding of the brain, glia have gone from stage-hands to co-stars.   My guest today is Dr. Nicola Allen. Nicola is a molecular neuroscientist and Associate Professor at the Salk Institute in La Jolla, California. She and her lab study the role of glial cells—especially astrocytes—in brain function and dysfunction.   Here, Nicola and I talk about how our understanding and appreciation of glial cells has changed. We do a bit of Brain Cells 101, reviewing the main division between neurons and glia and then sketching the subtypes within each category. We discuss the different shapes and sizes of glial cells, as well as the different functions. Glia are an industrious bunch. They’re involved in synapse formation and pruning, the production of myelin, the repair of injuries, and more. We also talk about how glial cells have been implicated in various forms of brain dysfunction, from neurodegeneration to neurodevelopmental syndromes. And how, as a result, these cells are attracting serious attention as a site for therapeutic intervention.   Well, it's that time of year again folks. Applications are now open for the 2025 Diverse Intelligences Summer Institute, or DISI. This is an intense program—highly interdisciplinary, highly international—for scholars and storytellers interested in all forms and facets of intelligence. If you like thinking about minds, if you like thinking about humans and animals and plants and AIs and collectives and ways they’re alike and different—you would probably like DISI. For more info, check out disi.org—that's D-I-S-I dot org. Review of applications begins March 1st, so don't dally too too long.   Alright friends—on to my conversation with Dr. Nicola Allen. Enjoy!   A transcript of this episode is available here.   Notes and links 3:00 – Correction: “glia” actually comes from the Greek—not the Latin—for “glue.” 3:30 – See this short primer on glia by Dr. Allen and Dr. Ben Barres. For a bit of the history of how glial cells were originally conceived, see this article on Ramón y Cajal’s contributions to glia research. 10:00 – On the nascent field of “neuroimmunology,” see here. 14:00 – On the idea that “90% of brain cells are glia” see this article by (former guest) Suzana Herculano-Houzel. 18:00 – The root “oligo” in “oligodendrocyte” means “few” (and is thus the same as the “olig” in, e.g., “oligarchy"). It is not related to the “liga-” in “ligament.” 28:00 – On the idea that the glia-neuron ratio changes as brains grow more complex, see again the article by Dr. Herculano-Houzel. 30:00 – See Dr. Allen’s paper on the idea of glia as “architects.” See also Dr. Allen’s paper on the idea of glia as “sculptors.” 33:00 – See Dr. Allen’s paper on the idea of the “tripartite synapse.” 42:00 – A recent paper reviewing the phenomenon of adult neurogenesis.  48:00 –  See Dr. Allen’s recent review of the role of astrocytes in neurodegeneration. 51:30 – A recent article on the roles of APOE in Alzheimer’s.   Recommendations Glia (2nd edition), edited by Beth Stevens, Kelly R. Monk, and Marc R. Freeman   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. Our transcripts are created by Sarah Dopierala.   Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].    For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

How do we learn? Usually from experience, of course. Maybe we visit some new place, or encounter a new tool or trick. Or perhaps we learn from someone else—from a teacher or friend or YouTube star who relays some shiny new fact or explanation. These are the kinds of experiences you probably first think of when you think of learning. But we can also learn in another way: simply by thinking. Sometimes we can just set our minds to work—just let the ideas already in our heads tumble around and spark off each other—and, as if by magic, come away with a new understanding of the world. But how does this happen exactly? And does it only happen in humans?    My guest today is Dr. Tania Lombrozo. Tania is a Professor of Psychology at Princeton University; she and her research group study learning, reasoning, explanation, belief, and more. In a recent paper, Tania outlines this puzzling alternative form of learning—learning by thinking, as it’s known—and presents evidence that it happens in both humans and AIs.   In this conversation, Tania and I talk about her longstanding work on explanation, and how it led her to study this less-obvious form of learning. We zoom in on four flavors of learning by thinking—learning through explanation, through simulation, through analogy, and through reasoning. We talk about the evidence that machines also learn in this way, and we consider whether animals could, too. We discuss how to resolve the paradox at the heart of "learning by thinking": how it could be that reshuffling old bits of knowledge can actually lead to new understanding. Along the way, Tania and I touch on: chain-of-thought prompting in LLMs, the Reddit community 'Explain Like I'm Five,’ the illusion of explanatory depth, the power of thought experiments, Darwin and Galileo, imagination and rationalization, how psychology and philosophy complement each other, and whether we can also learn—not just by thinking in our proverbial armchairs—but also by writing and talking.   So, happy 2025, friends! We've got some great stuff lined up for the coming year. If you like what we're doing with the show, we would—as ever—appreciate your support. And the main way you can support us is just by helping us get the word out—by telling a friend about us, or a colleague, or a student, or your thousands of social media followers.   Alright, without further ado, on to my conversation with Dr. Tania Lombrozo. Enjoy!   A transcript of this episode is available here.    Notes and links 3:30 – An influential early paper on “chain-of-thought prompting” in Large Language Models. A recent preprint by a team, including Dr. Lombrozo, exploring the cases where “chain-of-thought prompting” actually impairs performance in LLMs. 8:00 – For some of Dr. Lombrozo’s important earlier work on explanation, see here and here. 11:15 – The Reddit community ‘Explain Like I’m Five.’ 13:00 – An early paper on the “curse of knowledge”—the difficulty of ignoring what you know. 19:00 – Dr. Lombrozo’s recent review article on “learning by thinking” is here. Another article of hers on the same topic is here. 20:00 – The original report of the “self-explanation” effect. The original report of the “illusion of explanatory depth.” 30:00 – For a basic description of Galileo’s falling bodies thought experiment, see here. A discussion of this thought experiment by philosopher Tamar Gendler. 38:00 – For analysis of Darwin’s analogy between artificial and natural selection, see here and here. 42:00 – A paper on rationalization by Fiery Cushman.  48:00 – A paper from Dr. Lombrozo’s lab on “need for explanation.” The original paper describing the construct of “need for cognition.” 52:00 – The original report of “framing effects” by Tversky and Kahneman. 54:00 – A paper by Annette Karmiloff-Smith discussing “representational redescription.” 1:02:00 – A recent overview of issues surrounding “explainable” AI.    Recommendations Alison Gopnik, Andrew Meltzoff, & Patricia Kuhl, The Scientist in the Crib Frank Keil, Wonder: Childhood and the Lifelong Love of Science   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. Our transcripts are created by Sarah Dopierala.   Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].    For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).

Happy holidays, friends! We will be back with a new episode in January 2025. In the meantime, enjoy this favorite from our archives! ----- [originally aired Jun 14, 2023] Have you heard of Octopolis? It’s a site off the coast of Australia where octopuses come together. It’s been described as a kind of underwater "settlement" or "city." Now, smart as octopuses are, they are not really known for being particularly sociable. But it seems that, given the right conditions, they can shift in that direction. So it's not a huge leap to wonder whether these kinds of cephalopod congregations could eventually give rise to something else—a culture, a language, maybe something like a civilization.  This is the idea at the center of Ray Nayler's new book, The Mountain in the Sea. It's both a thriller of sorts and a novel of ideas; it’s set in the near future, in the Con Dao archipelago of Vietnam. It grapples with the nature of intelligence and meaning, with the challenges of interspecies communication and companionship, and ultimately with what it means to be human.  Here, Ray and I talk about how he got interested in cephalopods and how he came to know the Con Dao archipelago. We discuss some of the choices he made as an author—choices about what drives the octopuses in his book to develop symbols and about what those symbols are like. We consider the major human characters in his book, in particular two ambitious researchers who embody very different approaches to understanding minds. We also talk a fair bit about AI—another central character in the book, after all, is a super-intelligent android. Along the way, Ray and I touch on Arrival, biosemiotics, the nature of symbols, memory and storytelling, embodiment, epigenetics, cephalopod camouflage, exaptation, and the sandbox that is speculative fiction.  This episode is obviously something a little different for us. Ray is a novelist, after all, but he’s also an intellectual omnivore, and this conversation, maybe more than any other we’ve had on the show, spans three major branches of mind—human, animal, and machine. If you enjoy this episode, note that The Mountain in the Sea just came out in paperback, with a jaw-droppingly cool cover, I’ll add. I highly recommend that you check it out. One more thing, while I have you: If you're enjoying Many Minds, we would be most grateful for your help in getting the word out. You might consider sharing the show with a friend or a colleague, writing us a review on Apple Podcasts, or leaving us a rating on Spotify or Apple. All this would really help us grow our audience.  Alright friends, on to my conversation with Ray Nayler. Enjoy!    A transcript of this episode is available here.     Notes and links 8:30 – For the review of The Mountain in the Sea in question, see here.  14:00 – Con Dao is a national park in Vietnam. 17:00 – For our previous episode about cephalopods, see here. 19:00 – For a book-length introduction to biosemiotics, see here.   24:00 – A video of Japanese macaques washing sweet potatoes.  26:30 – For discussion of the human case, in which environmental pressures of some kind may have propelled cooperation, see our episode with Michael Tomasello.  29:00 – A popular article about RNA editing in cephalopods.  35:00 – A video of the “passing cloud” phenomenon in cuttlefish. A brief article about the phenomenon. A video showing other forms of camouflage in octopuses. 41:00 – An experimental exploration of the movement from “iconic” to “symbolic” communication in humans.  44:00 – A popular article about the communication system used in the movie Arrival.  49:00 – One source of inspiration for Ray’s book was Eduardo Kohn’s How Forests Think.  1:00:00 – An article on the idea of “architects” and “gardeners” among writers.  1:05:00 – Ray’s story ‘The Disintegration Loops’ is available here. 1:11:00 – Ray’s story ‘The Summer Castle’ is available here.  1:13:00 – A popular article about the phenomenon of highly superior autobiographical memory. An essay about the idea that faulty memory is a feature rather than a bug. 1:18:00 – Ray’s story ‘Muallim’ is available here.   Recommendations Ways of Being, by James Bridle Living in Data, by Jer Thorp   Follow Ray on Twitter.   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. Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here! We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].   For updates about the show, visit our website or follow us on Twitter: @ManyMindsPod.