From the archive: Cities, cells, and the neuroscience of navigation
Release Date: 08/07/2024
Life, free energy, and the pursuit of goals
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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 . Kate is a philosopher at the University of Edinburgh and the author of the...
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Universal emotions in fact and fiction
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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 , an Associate Professor of English Literature at Arizona State University. Brad is the author of a new book, ; in it he maps the landscape of debate around this long-contested topic....
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From the archive: Fermentation, fire, and our big brains
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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...
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Howl, grunt, sing
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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 , a zoologist at Cambridge University. Arik is an expert on vocal communication across the animal kingdom and the author of the recent book . Here, Arik and I talk about why the...
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The development of evolution
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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...
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String theories
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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 . Roope is a...
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The other half of the brain
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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...
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A paradox of learning
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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...
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From the archive: The octopus and the android
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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...
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Your brain on language
Many Minds
Using language is a complex business. Let's say you want to understand a sentence. You first need to parse a sequence of sounds—if the sentence is spoken—or images—if it's signed or written. You need to figure out the meanings of the individual words and then you need to put those meanings together to form a bigger whole. Of course, you also need to think about the larger context—the conversation, the person you're talking to, the kind of situation you're in. So how does the brain do all of this? Is there just one neural system that deals with language or several? Do different...
info_outlineHi friends, we're still on a brief summer break. We'll have a new episode for you later in August. In the meanwhile, enjoy this pick from our archives!
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[originally aired September 21, 2022]
If your podcast listening habits are anything like mine, you might be out for a walk right now. Maybe you’re wandering the neighborhood, just blocks from home, or maybe you’re further afield. In either case, I’m guessing you’re finding your way without too much trouble—you’re letting some intuitive sense steer you, track how far you’ve gone, tell you where to go next. This inner navigator of yours is doing all in the background, as your mind wanders elsewhere, and magically it gets it all right. Most of the time, anyway. But how is it doing it? What allows us to pull this off?
My guest today is Dr. Hugo Spiers, Professor of Cognitive Neuroscience at University College London. His lab studies how our brains "remember the past, navigate the present, and imagine the future.” In recent years Hugo and his group have used a wide variety of methods—and some astonishingly large datasets—to shed light on central questions about human spatial abilities.
Here, Hugo and I do a quick tour of the neuroscience of navigation—including the main brain structures involved and how they were discovered. We talk about research on a very peculiar population, the London taxi driver. We discuss the game Sea Hero Quest and what it's teaching us about navigation abilities around the world. We also touch on what GPS might be doing to us; whether the hippocampus actually resembles a seahorse; the ingenious layout of our brain's inner grids; navigation ability as an early sign of Alzheimer's; how “place cells” actually map more than just place; and how the monarch butterfly finds its way.
Super excited to share this one folks—this is an episode that's been on our wish list for some time. For mobile organisms like us, navigation is life or death—it’s as basic as eating or breathing. So when we dig into the foundations of these spatial abilities, we’re really digging into some of the most basic foundations of mind.
So let’s get to it. On to my conversation with Dr. Hugo Spiers. Enjoy!
A transcript of this episode is available here.
Notes and links
4:00 – A brief documentary about a person with developmental topographical disorder.
8:00 – There have been a slew of popular articles about the question of whether GPS is undermining our navigation abilities—see here and here.
12:00 – A classic academic article about path integration in mammals.
14:00 – The classic academic article by Edward Tolman on the idea of “cognitive maps.”
16:00 – A side-by-side comparison of a human hippocampus and seahorse. The resemblance is indeed striking.
18:00 – A classic academic article reporting “place cells” in rats.
21:00 – A research article on seasonal changes in hippocampus size across different species.
22:00 – A recent academic article on interactions between the hippocampus and the striatum in navigation.
23:30 – An article reviewing the first decade of research on “grid cells.” A video showing the activity of grid cells in a rat.
26:00 – The long struggle to calculate longitude is subject of a much-beloved book by Dava Sobel.
27:00 – The press release announcing the Nobel prize for the discovery of grid cells and place cells.
31:00 – A popular article about ‘The Knowledge’—a famed test for London taxi drivers.
33:30 – The celebrated original study by Eleanor Maquire and colleagues on structural changes in the brains of London taxi drivers. The (also-celebrated) follow-up study that Dr. Spiers was part of, comparing London taxi and bus drivers.
37:00 – More about the Taxi Brains project can be found here.
41:00 – A recent paper by Dr. Spiers’ team, led by Eva-Maria Griesbauer, reviews the cognitive neuroscience studies on London taxi drivers and dives deep into the learning techniques the drivers use.
44:30 – A paper by Dr. Spiers and team providing an overview of Sea Hero Quest and the studies it has been used for to date. A video demo of the game, and a popular article describing its motivation. Dr. Spiers developed the idea for the game in collaboration with Michael Hornberger.
50:00 – A recent research article looking at the value of Sea Hero Quest in detecting those at risk for Alzheimers.
53:00 – One of the first studies by Dr. Spiers and colleagues using Sea Hero Quest to test a vast sample and examine effects of variables like age, gender, and nationality.
54:30 – A more recent paper by Dr. Spiers and colleagues examining the effect of growing up in cities that are more or less “griddy.”
57:00 – A study by Dr. Spiers and colleagues showing a relationship between real-world navigation ability and navigation performance in Sea Hero Quest.
1:04:00 – The website of the International Orienteering Foundation. A video showing the sport.
1:06:00 – A review paper by Dr. Spiers and colleagues about the potential roles of cognitive maps in navigation and beyond.
1:07:00 – A review of “concept cells”, aka “Halle Berre cells.”
1:08:00 – A recent opinion piece by Dr. Spiers on the question of how many maps—and of what kind—the hippocampus implements.
1:10:30 – A recent research article on “time cells” in the hippocampus.
1:14:30 – A recent review article about monarch butterfly navigation.
Dr. Spiers recommends:
Human Spatial Navigation, by Ekstrom, Spiers, Bohbot, and Rosenbaum
‘The Cognitive Map in Humans: Spatial Navigation and Beyond,’ by Epstein, Patai, Julian, and Spiers
You can read more about Dr. Spiers work on his website and follow him 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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