The inner life of the hand
Many Minds
Newton saw in the human hand proof of the divine; Darwin saw a key to our species' success. Many others, too, have described the hand in hyperbolic terms, as a paragon of design, a cornerstone of human uniqueness, an engine of our achievements. But what makes the human hand so powerful? Is it the proportions of the fingers? Is it the opposability of the thumb? Or, could it be none of this? Could it be that the real power of our hands lies—not in the physical design—but elsewhere, out of sight? My guest today is . Matt is Professor of Cognitive Neuroscience at Birkbeck, University of...
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From the archive: The cuttlefish and its coat of many colors
Many Minds
Hi friends! We're skipping a beat to take care of some spring housekeeping tasks. We will be back in May! In the meanwhile, enjoy this listener favorite from our archives! ----- [originally aired April 30, 2025] We humans have a hard time becoming invisible. For better or worse, we're basically stuck with the skin and body we have; we’re pretty fixed in our color, our shape, our overall appearance. And so we're fascinated by creatures that aren't—creatures that morph to meet the moment, that can functionally disappear, that can shape-shift on a dime. And no creatures are more skilled,...
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Illuminating cave art
Many Minds
Deep in our past, in the dark depths of caves, our ancestors did something strange and beautiful. Working by firelight, some doodled little designs. Others made hand stencils. Some saw a bulge of rock, or a crack in the wall, and thought to turn it into a horse or a bison. Why did they make this art? What did it mean to them? Who were these artists? These questions are old—very old—but thanks to new methods and new interpretive frameworks, archaeologists are beginning to see them in a new light. My guest today is . Izzy is an archaeologist at Aarhus University in Denmark,...
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What can AI teach us about the mind?
Many Minds
Everyone is talking about AI these days. Often these conversations are about how AI might upend education, or work, or social life, or maybe civilization itself. But among cognitive scientists and psychologists the conversation inevitably drifts toward other questions. What does this latest generation of AI tell us about the human mind? Is it putting old ideas and theories to rest? Is it ushering in new ones? Will AI—in other words—also upend cognitive science? My guests today are and . Mike is a Professor of Psychology at Stanford University, where focuses on language learning and...
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Mutualisms all the way down
Many Minds
No one is an island. We all depend on each other in critical, often tangled ways. And when I say "we" and "each other" I don't just mean humans. Yes, we humans rely on other humans. But we also rely on bees, yeasts, dogs, bacteria, and countless other creatures big and small. These interspecies dependencies—or mutualisms, as biologists call them—have deflected and inflected our history. And there's no doubt they will also inflect our future. My guest today is . Rob is Professor of Applied Ecology at North Carolina State University, where he studies the creatures and ecologies all...
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Seven metaphors for AI
Many Minds
If you wanted a petri dish for understanding metaphors—how they emerge and evolve and jostle with each other—it would be hard to do better than the world of AI. We talk about AI systems variously as coaches or co-pilots, little genies or alien intelligences. Some researchers claim that AIs "grow," that they're entering their phase of "adolescence." Critics deride AI products as slop and dismiss LLMs as a kind of autocomplete on steroids. What's behind these different characterizations? Which ones are accurate and which are unfair? And are our metaphors mostly colorful rhetoric or do they...
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Origins of the kiss
Many Minds
Humans do some pretty weird things. Some of us will sit in searingly hot rooms or jump into icy ponds. Others risk their lives trying to climb to new heights or dive to new depths. And every once in a while, two otherwise normal-seeming humans will lean in close to each other, open mouths, lock lips, and swap a hearty helping of microbes. You may even know people who've done this. But why? Are we the only animals who kiss? What could be the deeper origins of this truly bizarre behavior? My guest today is Dr. . Matilda is an Evolutionary Biologist at the University of Oxford. She's...
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The aura of metaphor
Many Minds
Metaphors matter. They enliven our speech and our prose; they animate our arguments and stir our passions. Some metaphors power political movements; others propel scientific revolutions. These little figures of speech delight, provoke, captivate, shock, amuse, and galvanize us. In one way or another, metaphors just seem to help us make sense of a messy world. But how do they do all this? Whence their peculiar powers? What does it say about the human mind that we just can’t escape our metaphors—and frankly don’t want to? My guest today is . Steve is an Assistant Professor of...
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From the archive: How should we think about IQ?
Many Minds
Hello friends, and happy new year! We're gearing up for a new run of episodes starting later in January. In the meanwhile, enjoy this pick from our archives. ------ [originally aired October 16, 2024] IQ is, to say the least, a fraught concept. Psychologists have studied IQ—or g for “general cognitive ability”—maybe more than any other psychological construct. And they’ve learned some interesting things about it. That it's remarkably stable over the lifespan. That it really is general: people who ace one test of intellectual ability tend to ace others. And that IQs have...
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From 'On Humans': Can the brain understand itself?
Many Minds
Hello there, friends! We hope you're having a restful holiday, or a lively holiday, or whatever mix of those you prefer. As the year draws to a close, we at Many Minds are taking a much needed pause ourselves. But we wanted to share with you an episode from a podcast that we've been following for some time called . It's hosted by Ilari Mäkelä. It looks at humanity from all angles to understand where we come from and where we're going. The episode we're sharing features an interview with biologist and historian of science, Matthew Cobb; he's also the author of the book, . In...
info_outlineHumans do some pretty weird things. Some of us will sit in searingly hot rooms or jump into icy ponds. Others risk their lives trying to climb to new heights or dive to new depths. And every once in a while, two otherwise normal-seeming humans will lean in close to each other, open mouths, lock lips, and swap a hearty helping of microbes. You may even know people who've done this. But why? Are we the only animals who kiss? What could be the deeper origins of this truly bizarre behavior?
My guest today is Dr. Matilda Brindle. Matilda is an Evolutionary Biologist at the University of Oxford. She's interested in understanding the origins of behaviors and traits across the animal kingdom. But it's not just any traits she's interested in—she tends to favor those that are a bit risque.
Here, Matilda and I talk about the puzzle at the heart of human kissing behavior. We discuss the possible adaptive functions of kissing—and of romantic kissing in particular. We walk through her recent paper in which—drawing on observations across primates species—she and her colleagues reconstructed the phylogeny of kissing behavior. They found that kissing is present in almost all the Great Apes—and also in several species of monkeys—and that it may go back around 20 million years. We sketch different proposals for how kissing may have evolved, such as the idea that it originally grew out of “premastication”—the practice of chewing up food for infants and transferring that food by mouth. And, of course, we consider the cultural side of kissing—and how to make sense of the fact that, despite these ancient roots in the primate lineage, romantic kissing is by no means universal to all human groups.
Hope you enjoy this one, friends—offered in spirit of Valentine's Day, of course. Kissing may seem like a light-hearted or frivolous topic, but—as I hope you'll appreciate—it opens up some big, thorny, compelling questions. And, in fact, it's finally attracting serious attention from scholars of all kinds interested in the different dimensions of social behavior.
Without further ado, here's my interview with Dr. Matilda Brindle.
Notes
3:00 – Dr. Brindle’s paper, ‘A comparative approach to the phylogeny of kissing,’ coauthored with Dr. Catherine Talbot and Dr. Stuart West.
10:00 – An academic review of “postcopulatory sexual selection.”
15:45 – The study examining the convergence of oral microbiota in kissing couples. The same study quantified the amount of microbial transfer during kissing.
18:00 – For more on the “grass-in-ear” phenomenon among chimpanzees and other such arbitrary-seeming animal behaviors, see our earlier episode about animal cultures. For the more recent “grass-in-bum” phenomenon, see here.
21:30 – For Dr. Brindle’s work on the adaptive functions of masturbation in primates, see here.
32:00 – For popular coverage of Dr. Brindle’s work, highlighting the likelihood that humans and Neanderthals kissed, see here.
39:00 – The book, Biological Exuberance, by Bruce Bagemihl.
43:00 – For the study on the presence of romantic kissing across cultures, see here.
47:00 – For indirect (linguistic) evidence for the prevalence of “smell-kissing” across Southeast Asia, see here. For more on this style of greeting, see Kensy's post here.
50:00 – For the proposal that kissing is rooted in “oral grooming,” see here.
58:00 – For the larger special issue on the origins of kissing, of which Dr. Brindle’s paper is part, see here.
1:00:30 – For Dr. Brindle’s work on “bacula” (aka “penis bones”), see here.
Recommendations
The Handshake, by Ella Al-Shamahi
Eve, by Cat Bohannon
Primate Sexuality, by Alan Dixson
Many Minds is a project of the Diverse Intelligences Summer Institute, which is made possible by a generous grant from the John Templeton Foundation to Indiana University. The show is hosted and produced by Kensy Cooperrider, with help from Assistant Producer Urte Laukaityte and with creative support from DISI Directors Erica Cartmill and Jacob Foster. Our artwork is by Ben Oldroyd.
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