Many Minds

A cluster of brain cells in a dish, pulsing with electrical activity. A bee buzzing its way through a garden in bloom. A newborn baby staring up into his mother's eyes. What all these entities have in common is that we don't quite know what it’s like to be them—or, really, whether it's like anything at all. We don't really know, in other words, whether they’re conscious. But maybe we could know—if only we developed the right test.

My guest today is Dr. Tim Bayne. Tim is Professor of Philosophy at Monash University in Melbourne, Australia. He’s a philosopher of mind and cognitive science, with a particular interest in the nature of consciousness. Along with a large team of co-authors, Tim recently published an article titled 'Tests for consciousness in humans and beyond.' In it, they review the current landscape of consciousness tests—or “C-tests”, as they call them—and outline strategies for building more and better tests down the road.

Here, Tim and I discuss what consciousness is and why theories of it seem to be proliferating. We consider several of the boundary cases that are most hotly debated right now in the field—cases like brain organoids, neonates, and split-brain patients. We sketch a few of the most prominent current consciousness tests: the command following test, the sniff test, the unlimited associative learning test, and the test for AI consciousness. We talk about how we might be able to inch our way, slowly, toward something like a thermometer for consciousness: a universal test that tells us whether an entity is conscious, or to what degree, or even what kind of conscious it is. Along the way, Tim and I talk about zombies, chatbots, brains in vats, and islands of awareness. And we muse about how, in certain respects, consciousness is like temperature, or perhaps more like happiness or wealth or intelligence, and maybe even a bit like fire.

I think you'll enjoy this one, friends—it's a thought-provoking conversation on a foundational topic, and one that takes us far and wide. So without further ado, here's my interview with Dr. Tim Bayne. Enjoy!

A transcript of this episode will be available soon.

Notes and links

4:45 – The philosopher Dan Dennett, who passed away in April, was known for his writings on consciousness—among them his 1991 book, Consciousness Explained.

7:00 –The classic paper on the neural correlates of consciousness, by Francis Crick and Christof Koch.

9:00 –A recent review of theories of consciousness by Anil Seth and Dr. Bayne.

10:00 –David Chalmers’ classic paper on the “hard problem” of consciousness.

13:00 –Thomas Nagel’s classic paper on what it’s like to be a bat.

20:00 – A recent paper by James Croxford and Dr. Bayne arguing against consciousness in brain organoids.

23:00 –A recent paper by Dr. Bayne and colleagues about the emergence of consciousness in infants.

27:00 –A recent paper by Dr. Bayne and colleagues about consciousness in split-brain patients. An earlier paper by Dr. Bayne on the same topic.

30:00 –A paper by Dr. Bayne, Dr. Seth, and Marcello Massimini on the notion of “islands of awareness.”

35:00 –The classic paper using the “(covert) command following test” in a patient in a so-called vegetative state.

38:00 –A 2020 paper introducing the “sniff test.”

40:00 –A recent primer on the “unlimited associative learning” test.

43:00 –An essay (preview only), by the philosopher Susan Schneider, proposing the AI consciousness test.

50:00 – The history of the scientific understanding of temperature is detailed in Hasok Chang’s book, Inventing Temperature.

53:30 –Different markers of consciousness in infants are reviewed in Dr. Bayne and colleagues’ recent paper.

1:03:00 –The ‘New York Declaration on Animal Consciousness’ was announced in April. Read about it here.

Recommendations

Being You, Anil Seth

Into the Gray Zone, Adrian Owen

Other Minds, Peter Godfrey-Smith

Many Mindsis a project of theDiverse 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.

Welcome back friends! Today we've got a first for you: our very first audio essay by... not me. I would call it a guest essay, but it's by our longtime Assistant Producer, Urte Laukaityte. If you're a regular listener of the show, you've been indirectly hearing her work across dozens and dozens of episodes, but this is the first time you will be actually hearing her voice.

Urte is a philosopher. She works primarily in the philosophy of psychiatry, but also in the philosophy of mind, the philosophy of biology, the history of medicine, and neighboring fields. She's particularly interested in a colorful constellation of psychiatric phenomena—phenomena like hypnosis, mass hysteria, psychogenic conditions, and (the topic of today's essay) the placebo effect.

There's almost certainly more to placebo than you realize—it's a surprisingly many-layered phenomenon. Here, Urte pulls apart those layers. She talks about what placebo can and cannot do, the mechanisms by which it operates, the ethical dimensions of its use, its evil twin nocebo, how it is woven through the history of medicine, and a lot more. She argues that, though we've learned a lot about the placebo in recent decades, we have not yet harnessed its full potential.

As always, we eagerly welcome your comments about the show. Feel free to find us on social media, or send us a note at [email protected]. We would love to hear your suggestions for future episodes, your constructive criticisms, really your feedback of whatever kind.

Alright friends, now on to our audio essay—'Rehabilitating placebo’—written and read by Urte Laukaityte. Enjoy!

A text version of this episode will be available soon.

Notes and links

3:30 –A research paper describing the FIDELITY trial.

8:00 – For a neuroscientific overview of placebo research, see this review article. The landmark 1978 study is here.

9:00 –The study using naloxone in rats.

10:30 – A review of placebo effects in Parkinson’s disease.

13:00 – The study showing placebo effects in allergy sufferers. For more on placebo and conditioning in the immune system, see here.

13:30 –An overview of the results on whether placebo “can replace oxygen.”

16:00 –For the “milkshake” study, see here.

20:00 – A perspective piece on open-label placebos. A review of the efficacy of open-label placebos.

22:00 –A review of nocebo-induced side effects within the placebo groups of trials.

24:00 – On the idea of “good placebo responders,” see here.

27:30 –The book Medical Nihilism, by Jacob Stegenga.

28:00 – A review and meta-analysis of the use of placebo by clinicians.

29:30 ­– A paper on complementary and alternative medicine (CAM) and placebo.

30:30 –A review of factors modulating placebo effects.

34:00 – For the “signaling theory of symptoms,” see here.

Many Minds is a project of theDiverse 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.

They tend to move under the cover of darkness. As night descends, they come for your gardens and compost piles, for your trashcans and attic spaces. They are raccoons, skunks, and coyotes. And if you live in urban North America, they are a growing presence. Whether you consider them menacing, cute, fascinating, or all of the above, you have to grant that they are quite a clever crew. After all, they've figured how to adapt to human-dominated spaces. But how have they done this? What traits and talents have allowed them to evolve into this brave new niche? And are they still evolving into it?

My guest today is Dr. Sarah Benson-Amram. Sarah is Assistant Professor of Forest and Conservation Sciences and Zoology at the University of British Columbia; she also directs the Animal Behavior & Cognition Lab at UBC. Sarah's research group focuses on the behavioral and cognitive ecology of urban wildlife. They ask what urban wildlife can teach us about animal cognition more generally and try to understand ways to smooth human-wildlife interactions.

Here, Sarah and I talk about her work on that trio I mentioned before: raccoons, skunks, and coyotes. These three species are all members of the mammalian order of carniovora, a clade of animals that Sarah has focused on throughout her career and one that has been underrepresented in studies of animal cognition. We discuss the traits that have allowed these species—and certain members of these species—to thrive in dynamic, daunting urban spaces. We also talk about the big picture of the evolution of intelligence—and how urban adapter species might shed light on what is known as the cognitive buffer hypothesis. Along the way, we touch on: the neophilia of raccoons and the neophobia of coyotes, puzzle boxes, the Aesop's fable task, hyenas and elephants, brain size, individual differences, human-wildlife conflict, comparative gastronomy, and the cognitive arms race that might be unfolding in our cities.

If you have any feedback for us, we would love to hear from you. Guest suggestions? Topics or formats you'd like to see? Blistering critiques? Effusive compliments? We're open to all of it. You can email us at manymindspodcast at gmail dot com. That's manymindspodcast at gmail. Though, honestly, if it's really an effusive compliment feel free to just post that publicly somewhere.

Alright friends, on to my conversation with Sarah Benson-Amram. Enjoy!

A transcript of this episode will be available soon.

Notes and links

8:50 –A study of manual dexterity in raccoons.

11:30 – A video featuring raccoon chittering, among other vocalizations.

12:00 ­– A recent academic paper on the categorization of wildlife responses to urbanization—avoider, adapter, exploiter—with some critical discussion.

14:00 –A study of how animals are becoming more nocturnal in response to humans.

18:00 –An encyclopedia article on the Social Intelligence Hypothesis, by one of its originators, Richard Byrne. A recent appraisal of how the hypothesis has fared across different taxa.

18:30 –A recent review article by Dr. Benson-Amram and colleagues surveying carnivore cognition.

25:00 ­– On the question of urban vs rural animals, see the popular article, ‘Are cities making animals smarter?’

28:00 – A study by Dr. Benson-Amram and colleagues using puzzle boxes to study behavioral flexibility in captive raccoons. See also her follow-up study, conducted with a large team of neuroscience collaborators, examining the brains of raccoons who successfully solved the puzzle boxes.

34:30 –One of Dr. Benson-Amram’s earlier studies on innovative problem solving in hyenas.

36:30 – Our earlier episode on animal personality with Dr. Kate Laskowski.

39:00 –A study by Dr. Benson-Amram and colleagues exploring raccoons’ ability to solve the Aesop’s Fable task. She has also used this task with elephants.

44:00 – A study by Dr. Benson-Amram and colleagues examining reversal learning in raccoons, skunks, and coyotes.

49:00 – An article articulating the “cognitive buffer hypothesis.”

51:00 –A paper discussing—and “reviving”—the so-called ecological intelligence hypothesis.

53:00 –A study by Dr. Benson-Amram and colleagues comparing brain size and problem-solving ability in mammalian carnivores.

56:00 – A paper by Dr. Benson-Amram and colleagues on cognition in so-called nuisance species, in which they discuss the idea of a ‘cognitive arms race.’

57:30 – A paper on bin-opening in cockatoos and how it might be leading to an “innovation arms race.”

Recommendations

How Monkeys See the World, Dorothy Cheney and Robert Seyfarth

Are We Smart Enough to Know How Smart Animals Are? by Frans De Waal

An Immense World, by Ed Yong (featured in a previous episode!)

Urban Carnivores, by Stanley D. Gehrt, Seth P. D. Riley, and Brian L. Cypher

Many Minds is a project of theDiverse 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.

Hi friends, we're busy with some spring cleaning this week. We'll have a new episode for you in two weeks. In the meanwhile, enjoy this pick from our archives!

_____

[originally aired Nov 30, 2022]

When we talk about AI, we usually fixate on the future. What’s coming next? Where is the technology going? How will artificial intelligences reshape our lives and worlds? But it's also worth looking to the past. When did the prospect of manufactured minds first enter the human imagination? When did we start building robots, and what did those early robots do? What are the deeper origins, in other words, not only of artificial intelligences themselves, but of our ideas about those intelligences?

For this episode, we have two guests who've spent a lot of time delving into the deeper history of AI. One isAdrienne Mayor; Adrienne is a Research Scholar in the Department of Classics at Stanford University and the author of the 2018 book,Gods and Robots: Myths, Machines, and Ancient Dreams of Technology. Our second guest isElly Truitt; Elly is Associate Professor in the History & Sociology of Science at the University of Pennsylvania and the author of the 2015 book,Medieval Robots: Mechanism, Magic, Nature, and Art.

In this conversation, we draw on Adrienne's expertise in the classical era and Elly's expertise in the medieval period to dig into the surprisingly long and rich history of AI. We discuss some of the very first imaginings of artificial beings in Greek mythology, including Talos, the giant robot guarding the island of Crete. We talk about some of the very first historical examples of automata, or self-moving devices; these included statues that spoke, mechanical birds that flew, thrones that rose, and clocks that showed the movements of the heavens. We also discuss the long-standing and tangled relationships between AI and power, exoticism, slavery, prediction, and justice. And, finally, we consider some of the most prominent ideas we have about AI today and whether they had precedents in earlier times.

This is an episode we've been hoping to do for some time now, to try to step back and put AI in a much broader context. It turns out the debates we're having now, the anxieties and narratives that swirl around AI today, are not so new. In some cases, they're millennia old.

Alright friends, now to my conversation with Elly Truitt and Adrienne Mayor. Enjoy!

A transcript of this episode is availablehere.

Notes and links

4:00 – See Adrienne’sTedEd lesson about Talos, the “first robot.” See also Adrienne’s2019 talkfor the Long Now Foundation.

7:15 –The Throne of Solomon does not survive, but it was often rendered in art, for example inthis paintingby Edward Poynter.

12:00 – For more on Adrienne’s broader research program, see herwebsite; for more on Elly’s research program, see herwebsite.

18:00 – For more on the etymology of ‘robot,’ seehere.

23:00 – A recentpieceabout Aristotle’s writings on slavery.

26:00 –Anarticleabout the fact that Greek and Roman statues were much more colorful than we think of them today.

30:00 –Arecent research articleabout the Antikythera mechanism.

34:00 – See Adrienne’spopular articleabout the robots that guarded the relics of the Buddha.

38:45 –See Elly’sarticleabout how automata figured prominently in tombs.

47:00 – See Elly’srecent video lectureabout mechanical clocks and the “invention of time.” For more on the rise of mechanistic thinking—and clocks as important metaphors in that rise—see Jessica Riskin’s book,The Restless Clock.

50:00 – Anarticleabout a “torture robot” of ancient Sparta.

58:00 –Apaintingof the “Iron Knight” in Spenser’sThe Faerie Queene.

Adrienne Mayor recommends:

The Greeks and the New, by Armand D’Angour

Classical Traditions in Science Fiction, edited by Brett Rogers and Benjamin Stevens

In Our Own Image, by George Zarkadakis

Ancient Inventions, by Peter James and Nick Thorpe

Elly Truitt recommends:

AI Narratives, edited by Stephen Cave, Kanta Dihal, and Sarah Dillon

The Love Makers, by Aifric Campbell

The Mitchells vs the Machines

You can read more about Adrienne’s work on herwebsiteand follow her onTwitter. You can read more about Elly’s work on herwebsiteand follow her onTwitter.

Many Mindsis 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 byKensy 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/).

You can subscribe toMany Mindson Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you like to listen to podcasts.

**You can now subscribe to the Many Minds newsletterhere!**

We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].

For updates about the show, visit our website (https://disi.org/manyminds/),or follow us on Twitter:@ManyMindsPod.

We've all seen those illusions. The dots seem to dance, when in fact they're completely still. The lines look like they bend, but in reality they're perfectly straight. Here's the thing: It doesn't matter that you know the ground truth of these illusions—the dancing and bending won't stop. And that we see the world one way, even though we know it's actually another way, is a fascinating quirk of our minds—and maybe a telling one. It suggests that there's a chasm between perceiving and thinking, that these may be two independent provinces of the mind. But, if so, we're faced with another question: Where does perception end and thinking begin?

My guest today is Dr. Chaz Firestone. Chaz is an Associate Professor of Psychological and Brain Sciences at Johns Hopkins University, and Director of the Perception and Mind lab there. He and his research group study perceiving, thinking, and the interface between the two.

Here, Chaz and I talk about his background in philosophy and how it continues to animate his research. We sketch the differences between perception and cognition and why the two are best considered separate faculties. We consider the idea of so-called "top-down" effects on perception. We discuss the fact that, even if perception and cognition are separate, there's much more to perception than meets the eye. We seem to see things like causes and social interactions; we perceive things like silences and absences. Along the way, Chaz and I touch on the modular view mind, skeletal shapes, the El Greco fallacy, stubborn epistemology, birders and radiologists, retinotopy and visual adaptation, adversarial images, human-machine comparisons, and the case of the blue banana.

This is a fun one, friends. But before we get to it, one humble request. If you've been enjoying Many Minds, now would be a great time to leave us a rating or review. You can do this on Apple Podcasts or on Spotify. It would really help us grow and get the word out! It actually looks like our last review on Apple Podcasts is about 10 months old—so, if you have a minute, that could really use some freshening up.

Alright folks, on to my conversation with Chaz Firestone. Enjoy!

A transcript of this episode will be available soon.

Notes and links

3:00 – Dr. Firestone’s early paper reporting the Times Square experiment and the “skeletal shape” phenomenon.

8:00 – A visual explanation of the “missing bullet holes” graphic.

13:00 –Dr. Firestone has collaborated intensively with the philosopher Ian Phillips.

15:00 – A recent book by Ned Block, The Border Between Seeing and Thinking.

24:00 –Visual illusions are legion, as are inventories of them. See, for instance, this catalogue on Wikipedia or this Reddit thread.

25:00 – An obituary for Jerry Fodor, who died in 2017. The classic book by Zenon Pylyshyn, Computation and Cognition.

28:00 –A paper by Dr. Firestone about the history of the El Greco fallacy. An empirical paper by Dr. Firestone and Brian Scholl showing the El Greco fallacy at work in perception research.

35:00 – A target article (with commentaries) in Behavioral and Brain Sciences by Dr. Firestone and Dr. Scholl about claims of “top-down” effects on perception. Dr. Firestone has published other work on this theme, e.g., here, here, & here.

41:00 – A paper with discussion (and illustration) of the classic Dalmation Mooney image.

45:00 – A study of rapid visual pattern recognition in expert chess players.

50:30 –A paper by J.J. Valenti and Dr. Firestone about the case of the blue banana.

54:00 –A review paper by Alon Hafri and Dr. Firestone reviewing evidence that people actually perceive high-level relations like causality, support, and social interaction.

56:00 – A study by Martin Rolfs and colleagues about the perception of causality.

1:02:00 –A study by Liuba Papeo and colleagues about the perception of social interactions. A related paper showing an inversion effect.

1:04:00 –A paper by Alon Hafri and colleagues on the perception of roles in an interaction.

1:06:00 –A widely cited paper by J. Kiley Hamlin and colleagues on the recognition of social interactions in preverbal infants.

1:06:30 –A review paper on reading in the brain.

1:10:00 –A paper by Rui Goh, Dr. Phillips, and Dr. Firestone on the perception of silence.

1:18:00 – A recent review paper by Jorge Morales and Dr. Firestone about the dialogue between philosophy of perception and psychology, which discusses the perception of absence (among other case studies).

1:22:00 – A recent perspective piece by Dr. Firestone about human-machine comparisons.

1:25:00 - An empirical paper by Zhenglong Zhou and Dr. Firestone on the deciphering of adversarial images by humans.

1:28:00 – For a review of the mirror self-recognition test, see our earlier audio essay.

1:35:00 – Other interesting work going on in Dr. Firestone’s research group has investigated representational momentum, beauty, and epistemic actions, among other topics.

Recommendations

The Modularity of Mind, by Jerry Fodor

The Contents of Visual Experience, by Susanna Siegel

Psych, by Paul Bloom

Many Minds is a project of theDiverse 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.

If want to have a rich social life, you're going to need to know who's who. You'll need to distinguish friend from foe, sister from stranger. And you're going to need to hold those distinctions in your head— for at least a little while. This is true not just for humans but—we have to assume—for other social species as well. But which species? And for how long can other creatures hold on to these kinds of social memories?

My guests today are Dr. Laura Lewis and Dr. Chris Krupenye. Laura is a biological anthropologist and postdoctoral scholar at UC Berkeley; Chris is a comparative psychologist and an Assistant Professor at Johns Hopkins. Along with a larger team, Laura and Chris recently authored a paper on memory for familiar faces in chimpanzees and bonobos. In it, they show that our closest cousins remember their groupmates for decades.

Here, we chat about the paper and the backstory behind it. We consider the anecdotes about long-term memory in great apes—and how Laura and Chris decided to go beyond those anecdotes. We talk about the evidence for complex social memory across the animal kingdom. We discuss the use of eye-tracking with primates and its advantages over earlier methods. We also talk about why long-term social memory might have evolved. Along the way, we touch on dolphins, ravens, and lemurs; voices, gaits, and names; the different gradations of recognition; and how memory serves as a critical foundation for social life more generally.

Alright friends, without further ado, here's my conversation with Laura Lewis and Chris Krupenye. Enjoy!

A transcript of this episode will be available soon.

Notes and links

4:30 – Dr. Lewis and Dr. Krupenye worked together in the lab of Dr. Brian Hare, a former guest on the podcast.

8:30 –The video of Mama and the primatologist Jan van Hooff.

12:00 – For research on the remarkably long social memories of dolphin, see here.

14:00 – For research on long-term voice recognition in bonobos, see here.

19:30 – Another collaborator on the paper we’re discussing was Dr. Fumihiro Kano, affiliated with the Kumamoto Sanctuary.

29:30 – For more on the use of eye-tracking with primates, see a recent review paper by Dr. Lewis and Dr. Krupenye.

34:00 – For the previous study by Dr. Lewis, Dr. Krupenye, and colleagues about how bonobos and chimpanzees attend to current groupmates, see here.

41:00 –A popular article reviewing bonobo social behavior.

54:30 –A research paper on individual recognition by scent in chimpanzees.

55:30 –A research paper on individual recognition by butt in chimpanzees.

Recommendations

‘Long-term memory for affiliates in ravens’

‘Decades-long social memory in bottlenose dolphins’

‘Enduring voice recognition in bonobos’

Many Minds is a project of theDiverse 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.

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 et 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 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 will be available soon.

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. Bryan 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 theDiverse 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.

Where do memories live in the brain? If you've ever taken a neuroscience class, you probably learned that they're stored in our synapses, in the connections between our neurons. The basic idea is that, whenever we have an experience, the neurons involved fire together in time, and the synaptic connections between them get stronger. In this way, our memories for those experiences become minutely etched into our brains. This is what might be called the synaptic view of memory—it's the story you'll find in textbooks, and it's often treated as settled fact. But some reject this account entirely. The real storehouses of memory, they argue, lie elsewhere.

My guest today is Dr. Sam Gershman. Sam is Professor of Psychology at Harvard University, and the director of the Computational Cognitive Neuroscience Lab there. In a recent paper, he marshals a wide-ranging critique of the synaptic view. He makes a compelling case that synapses can't be the whole story—that we also have to look inside the neurons themselves.

Here, Sam and I first discuss the synaptic view and the evidence that seems to support it. We then talk about some of the problems with this classic picture. We consider, for example, cases where memories survive the radical destruction of synapses; and, more provocatively, cases where memories are formed in single-celled organisms that lack synapses altogether. We talk about the dissenting view, long lurking in the margins, that intracellular molecules like RNA could be the real storage sites of memory. Finally, we talk about Sam's new account—a synthesis that posits a role for both synapses and molecules. Along the way we touch on planaria and paramecia; spike-timing dependent plasticity; the patient H.M.; metamorphosis, hibernation, and memory transfer; the pioneering work of Beatrice Gelber; unfairly maligned ideas; and much, much more.

Before we get to it, one important announcement: Applications are now open for the 2024 Diverse Intelligences Summer Institute (or DISI)! The event will be held in beautiful, seaside St Andrews, Scotland, from June 30 to July 20. If you like this show—if you like the conversations we have and the questions we ask—it's a safe bet that you'd like DISI. You can find more info at disi.org—that's disi.org. Review of applications will begin on Mar 1, so don't delay.

Alright friends, on to my conversation about the biological basis of memory with Dr. Sam Gershman. Enjoy!

A transcript of this episode will be available soon.

Notes and links

4:00 - A general audience article on planarian memory transfer experiments and the scientist who conducted them, James V. McConnell.

8:00 - For more on Dr. Gershman’s research and general approach, see his recent book and the publications on his lab website.

9:30 - A brief video explaining long-term potentiation. An overview of “Hebbian Learning.” The phrase “neurons that fire together wire together” was, contrary to widespread misattribution, coined by Dr. Carla Shatz here.

12:30 - The webpage of Dr. Jeremy Gunawardena, Associate Professor of Systems Biology at Harvard University. A recent paper from Dr. Gunawardena’s lab on the avoidance behaviors exhibited by the single-celled organism Stentor (which vindicates some disputed, century-old findings).

14:00 - A recent paper by C. R. Gallistel describing some of his views on the biological basis of memory.

19:00 - The term “engram” refers to the physical trace of a memory. See recent reviews about the so-called search for the engram here, here, and here.

20:00 - An article on the importance of H.M. in neuroscience.

28:00 - A review about the phenomenon of spike-timing dependent plasticity.

33:00 - An article, co-authored by former guest Dr. Michael Levin, on the evidence for memory persistence despite radical remodeling of brain structures. See our episode with Dr. Levin here.

35:00 - A study reporting the persistence of memories in decapitated planarians. A popular article about these findings.

36:30 - An article reviewing one chapter in the memory transfer history. Another article reviewing evidence for “vertical” memory transfer (between generations).

39:00 - For more recent demonstrations of memory transfer, see here and here.

40:00 - A paper by Dr. Gershman, Dr. Gunawardena, and colleagues reconsidering the evidence for learning in single cells and describing the contributions of Dr. Beatrice Gelber. A general audience article about Gelber following the publication of the paper by Dr. Gershman and colleagues.

45:00 – A recent article arguing for the need to understand computation in single-celled organisms to understand how computation evolved more generally.

46:30 –Another study of classical conditioning in paramecia, led by Dr. Todd Hennessey.

49:00 –For more on plant signaling, see our recent episode with Dr. Paco Calvo and Dr. Natalie Lawrence.

56:00 – A recent article on “serial reversal learning” and its neuroscientific basis.

1:07:00 –A 2010 paper demonstrating a role for methylation in memory.

Recommendations

The Behavior of the Lower Organisms, by Herbert Spencer Jennings

Memory and the Computational Brain, by C. R. Gallistel and Adam Philip King

Wetware, by Dennis Bray

Many Minds is a project of theDiverse 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.

Welcome back folks! The new season of Many Minds is quickly ramping up. On today’s episode we’re thrilled to be rejoined byDr. Michael Muthukrishna. Michael is Associate Professor of Economic Psychology at the London School of Economics. He’s an unusually wide-ranging and rigorous thinker; though still early in his career, Michael has already made key contributions to our understanding of culture, intelligence, evolution, innovation, cooperation and corruption, cross-cultural variation, and a bunch of other areas as well.

We wanted to have Michael back on—not just because he was an audience favorite—but because he’s got a new book out. It’s titled A theory of everyone: The new science of who we are, how we get here, and where we’re going. In this conversation, Michael and I talk about the book and lay out that grand theory mentioned in the title. We discuss energy and how—since the very origins of life—it’s proven to be a fundamental, unshakeable constraint. We talk about the nature of human intelligence and consider the dynamics of human cooperation and innovation. We also delve into a few of the implications that Michael’s “theory of everyone” has for the future of our species. Along the way, we touch on carrying capacity, nuclear fusion, inclusive fitness, religion, the number line, multiculturalism, AI, the Flynn effect, and chaos in the brickyard.

If you enjoy this one, you may want to go back to listen to our earlier chat as well. But more importantly, you may want to get your hands on Michael’s book. It’s ambitious and inspiring and we were barely able to graze it here.

Alright friends, without further ado, on to my second conversation with Dr. Michael Muthukrishna. Enjoy!

A transcript of this episode will be available soon.

Notes and links

8:30 – Dr. Muthukrishna completed his PhD at the University of British Columbia, where he was advised by Joseph Henrich. He also worked with Ara Norenzayan, Steven Heine, and others.

9:30 – Previous books on dual-inheritance theory and cultural evolution mentioned here include The Secret of Our Success by Joseph Henrich, Not by Genes Alone by Peter Richerson and Robert Boyd, and Darwin’s Unfinished Symphony by Kevin Lala.

16:30 – Dr. Muthukrishna’s paper on the theory problem in psychology, drawn from his dissertation.

17:10 – The classic paper ‘Chaos in the Brickyard,’ about the need for theory-building in science.

22:00 – For a brief overview of Dr. Muthukrishna’s understanding of human intelligence and human uniqueness, see this recent paper. For an overview of cumulative culture in comparative perspective, see here.

23:00 – For the 2005 issue of Science magazine showcasing 25 big unanswered questions, see here.

23:30 – For the review paper on cooperation by Dr. Muthukrishna and Dr. Henrich, see here.

26:00 – For Dr. Muthukrishna’s empirical work that attempts to induce corruption in the lab, see here.

28:00 – The scholar Robert Klitgaard, mention here, is well-known for his research on corruption.

29:00 – See the preprint by Dr. Muthukrishna and colleagues titled ‘The size of the stag determines the level of cooperation.’

33:30 – A video laying out the RNA world hypothesis.

45:00 – For more on the evolution of human brain size, see our earlier conversation with Dr. Muthukrishna, as well as our conversation with Jeremy DeSilva.

47:00 – For the metric known as Energy Return on Investment (EROI), see here.

54:00 – For more on the cross-cultural variation in numeracy, see here.

55:20 – To correct the record, according to this review of rare numeral systems, there is only a single known base 8 system in the world’s languages.

57:15 – In our earlier conversation (around 42:00), we discussed the work by Luria on ‘If P, then Q’ reasoning.

57:30 – For more on the so-called WEIRD problem, see our earlier audio essay.

1:00:30 – For some experimental evidence consistent with the idea that language improves the transmission of cultural information, see here.

1:07:00 – For data on the acceleration of urbanization, see here.

1:16:00 – For a brief primer on land value taxes, see here.

1:18:30 –For the idea that Machiavelli’s The Prince was satire, see here.

Many Minds is a project of theDiverse 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.

And we’re back! It’s been awhile, friends. Hope you enjoyed your fall and your holidays. Thanks so much for re-joining us—we’re super excited to be kicking off a brand-new season of the Many Minds podcast. We thought we’d get things started this year with an audio essay, one partly inspired by some musings and mullings from my parental leave. Hope you enjoy it folks—and we’ll see you again in a couple weeks with our first interview of 2024.

Now on to ‘Dawn of the smile.’ Enjoy!

A text version of this episode will be available soon.

Notes and links

3:00 –Darwin describes his children’s first smiles in his 1872 book, The Expression of the Emotions in Man and Animals.

4:10 –On so-called Duchenne smiles, see this classic investigation.

5:00 – For a summary of “basic emotions” theory, see any number of Paul Ekman’s writing (e.g., here, here). For a recent articulation of the “social tools” theory, see writings by Alan J. Fridlund (e.g., here). For another influential recent critique of “basic emotions” theory, see here.

6:00 –For the classic bowling study, see here.

7:00 –For a recent review of facial expressions in blind people, see here.

7:45 –For a review of smiling and gender (and the importance of “rules and roles”), see here. For one of the studies linking smiliness to historical migration patterns, see here.

8:30 – For the historical shift in smiling—and its possible relation to the Kodak company—see here. For the yearbook photo analysis, see here.

9:30 – See Darwin’s discussion of infant laughter in The Expression of the Emotions in Man and Animals.

10:30 –For Darwin’s observations of laughter and smiles in primates, again, The Expression of the Emotions in Man and Animals. See Jan van Hooff’s classic study here.

11:30 –For the study comparing laughter across the Great Apes, see here. For the study of an “ape-like” stage in human laughter, see here.

12:30 –For a review of play vocalizations and laughter across species, see here.

13:20 – For the Marina Davila-Ross’s suggestion that laughter and smiles share a common evolutionary source, see here.

13:30 – For research on human infants’ open-mouthed smiles, see here.

14:00 –For the idea of the “acoustic origin” of the smile, see here.

Many Minds is a project of theDiverse 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.