How nature restores the mind
Many Minds
One afternoon you decide to snub your responsibilities and go for a hike. You spend a few hours in the woods or the mountains. You study the bark of trees, you bathe in birdsong, you let your eyes roam along a distant ridgeline. And you come back feeling better, restored somehow—like you have more energy, more patience, more bandwidth. We've all, I'm guessing, had experiences like this. But what's behind these effects? Why would nature restore us? What's the evidence that it really does? And what is even being restored, actually? My guest today is . Marc is an Associate Professor in the...
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From the archive: Revisiting the dawn of human cognition
Many Minds
Hi friends! We're taking a much-needed summer pause—we'll have new episodes for you later in September. In the meanwhile, enjoy this pick from our archives! ------- [originally aired June 1, 2023] There's a common story about the human past that goes something like this. For a few hundred thousand years during the Stone Age we were kind of limping along as a species, in a bit of a cognitive rut, let’s say. But then, quite suddenly, around 30 or 40 thousand years ago in Europe, we really started to come into our own. All of a sudden we became masters of art and ornament, of symbolism and...
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From the archive: Of molecules and memories
Many Minds
Hi friends! We're taking a much-needed August pause—we'll have new episodes for you in September. In the meanwhile, enjoy this pick from our archives! _____ [originally aired February 8, 2024] 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...
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From the archive: Consider the spider
Many Minds
Hi friends! We're taking a much-needed August pause—we'll have new episodes for you in September. In the meanwhile, enjoy this pick from our archives! _____ [originally aired May 30, 2024] Maybe your idea of spiders is a bit like mine was. You probably know that they have eight legs, that some are hairy. Perhaps you imagine them spending most of their time sitting in their webs—those classic-looking ones, of course—waiting for snacks to arrive. Maybe you consider them vaguely menacing, or even dangerous. Now this is not all completely inaccurate—spiders do have eight legs, after...
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The shaman with a thousand faces
Many Minds
When you hear the word "shaman," I'm guessing a web of associations starts to form in your mind. Perhaps you imagine strange ceremonies and strong substances; maybe you think of an earlier time when magic and superstition reigned. But shamanism is not just some relic of the past, or a curio from exotic lands. It's part of our present, and it will almost certainly be part of our future. This is because the roots of shamanism lie within us all. My guest today is . Manvir is an Assistant Professor of Anthropology at the University of California, Davis and to The New Yorker. He's also the author...
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Varieties of childhood
Many Minds
Childhood is a special time, a strange time. Children are adored and catered to—they're given their own menus and bedrooms. They're considered delicate and precious, and so we cushion them from every imaginable risk. Kids are encouraged to play, of course—but very often it's under the watchful eye of anxious adults. This, anyway, is how childhood looks in much of the United States today. But is this the way childhood looks everywhere? Is this the way human childhoods have always been? My guests today are and . Dorsa is an Assistant Professor of Psychology & Neuroscience at Duke...
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Science, AI, and illusions of understanding
Many Minds
AI will fundamentally transform science. It will supercharge the research process, making it faster and more efficient and broader in scope. It will make scientists themselves vastly more productive, more objective, maybe more creative. It will make many human participants—and probably some human scientists—obsolete… Or at least these are some of the claims we are hearing these days. There is no question that various AI tools could radically reshape how science is done, and how much science is done. What we stand to gain in all this is pretty clear. What we stand to lose is less obvious,...
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The primeval soil of play
Many Minds
Puppies wrestling and mock-biting each other. Toddlers playing hide and seek. Kittens pouncing—repeatedly—on a toy mouse. You've no doubt looked on at scenes like this with amusement. And you've no doubt seen some of those viral videos—of ravens sledding down hills, of bumble bees playing with balls. All these moments make us smile, maybe even giggle. But the scientific questions they raise merit serious attention. Where do we see play in the animal kingdom? Where do we not? What functions does play serve? Do we—and many other creatures—have an elemental need for play? My guest today...
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The big five and beyond
Many Minds
If you've heard anything about the study of human personality, you've probably heard about the “big five.” This is a framework that attempts to characterize human personality in terms of five broad factors or dimensions—neuroticism, extraversion, openness, conscientiousness, and agreeableness. The big five framework has been enormously influential, generating heaps and heaps of data, and study after study on the stability of personality, on the factors that shape our personalities, on how our personalities predict success and satisfaction. But is the big five really the best we can do?...
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Philosophers on psychedelics
Many Minds
Some call it the "psychedelic renaissance." In the last decade or so, interest in psychedelic drugs has surged—and not just among Silicon Valley types and psychiatrists and neuroscientists. It's also surged among a stereotypically soberer crowd: academic philosophers. The reasons are clear. With their varied and sometimes transformative effects, psychedelics raise ethical questions, epistemological questions, metaphysical questions, questions about the nature of experience and the nature of the mind. My guest today is . Chris is a philosopher of cognitive science at the University of Western...
info_outlineHi friends, we will be on hiatus for the fall. To tide you over, we’re putting up some favorite episodes from our archives. You may not be surprised to hear that the paper featured in this archive pick attracted a lot of attention. In the time since we first aired this episode, it prompted at least one direct critique, which then occasioned a reply by the authors.
Enjoy!
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You have a big brain. I have a big brain. We, as a species, have pretty big brains. But this wasn't always the case. Way back when, our brains were much smaller; then they went through a bit of growth spurt, one that lasted for a couple million years. This steady ballooning of brain size is one of the key themes of the human story. But then there's a late-breaking twist in that story—a kind of unexpected epilogue. You see, after our brains grew, they shrank. But when this shrinkage happened and—of course, why—have remained mysterious. My guest today is Jeremy DeSilva, a paleoanthropologist at Dartmouth College. He’s an expert on the evolution of the foot and ankle. But, it turns out the body is all connected, so he also thinks about brains and heads. In a recent paper, Jerry and his colleagues took up the mystery of human brain shrinkage. They first set out to establish more precisely when in our past this occurred. Using a large database of crania, spanning few million years, Jerry’s team was able to establish that this shrinkage event happened much more recently than previously thought—a mere 3000 years ago. Naturally, the next question was why? What happened around that time that could have possibly caused our brains to deflate? To answer this, Jerry and his collaborators turned to an unexpected source of insight: Ants. That’s right, ants. They argue that these ultrasocial critters may offer clues to why we might have suddenly dispensed with a chunk of brain about the size of a lemon. This is a really juicy paper and a super fun conversation, so we should just get to it. But I did want to mention: Jerry has a recent book from 2021 called First Steps that I whole-heartedly recommend. It’s about origins of upright walking in humans—which it turns out, is bound up with all kinds of other important aspects of being human. So definitely check that out!
Thanks folks—on to my chat with Dr. Jerry DeSilva. Enjoy!
The paper we discuss is available here. A transcript of this episode is available here.
Notes and links
3:00 – A podcast episode from the Leakey Foundation about the so-called “obstetrical dilemma.”
5:40 – A refresher for those who have trouble keeping their ‘cenes’ straight: the Pleistocene refers to the period from 2.58 million years ago to 11,700 years ago; immediately after that came the Holocene, which we are still in today.
7:00 – An article discussing the issue of unethical collections of human remains.
10:30 – The key figure form Dr. DeSilva’s paper—showing the changing “slopes” of brain size over time—is available here.
19:30 – The original article by Leslie Aiello and Peter Wheeler on the “expensive tissue hypothesis.” A more recent popular article on the hypothesis.
20:45 – An article by a major proponent of the social intelligence hypothesis, Dr. Robin Dunbar. A more critical review of the social intelligence hypothesis.
23:00 – A recent paper by Jeff Stibel and an older preprint by John Hawks evaluating the “body size” explanation of recent brain shrinkage.
24:00 – See our earlier episode on human self-domestication with Brian Hare.
29:00 – One of Dr. DeSilva’s collaborators on this research is Dr. James Traniello, who specializes in ants.
34:45 – An overview of the earliest history of writing.
37:20 – Dr. DeSilva’s book, First Steps, came out in 2021.
39:00 – A recent paper discussing the evolution of rotational birth in humans.
Dr. DeSilva recommends:
Kindred, by Rebecca Wragg Sykes (featured in an earlier episode!)
Origin, by Jennifer Raff
You can find Dr. DeSilva on Twitter.
Many Minds is a project of the Diverse Intelligences Summer Institute (DISI) (https://disi.org), which is made possible by a generous grant from the Templeton World Charity Foundation to UCLA. It is hosted and produced by Kensy Cooperrider, with help from Assistant Producer Urte Laukaityte and with creative support from DISI Directors Erica Cartmill and Jacob Foster. Our artwork is by Ben Oldroyd (https://www.mayhilldesigns.co.uk/). Our transcripts are created by Sarah Dopierala (https://sarahdopierala.wordpress.com/).
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