Blindness, neuroplasticity, and the origins of concepts

It’s an old question: How does experience shape our minds and brains? Some people play the piano; others drive taxis; others grow up trilingual. For years now, scientists have examined how these and other kinds of life experiences can lead to subtle differences in our concepts and cortexes. But to really push on the question, to really explore the limits of how experience can rewire us, some researchers have turned to an especially dramatic case: blindness. What does a life without visual input do to the mind and brain? My guest today is Dr. Marina Bedny, an Associate Professor of Psychological and Brain Sciences at Johns Hopkins University. For more than a decade now, Marina has been researching blindness and, in particular, what blindness can tell us much about where our concepts come from and about how our brains get organized. Here, Marina and I discuss how people who have been blind since birth nonetheless develop rich, sophisticated understandings of the visual world. We talk about how the visual cortex in blind folks gets repurposed for other decidedly non-visual functions, like language. We consider the intriguing findings that blind people very often outperform sighted people in certain kinds of tasks. On the way, we also touch on John Locke and the British empiricists; the notion of cortical recycling; the possibility of re-opening the brain's critical periods; and a bunch else.  This was a super thought-provoking conversation—I thoroughly enjoyed it, and I think you will too. But, before we get to it, a final reminder about the Diverse Intelligences Summer Institute, or DISI. This year’s DISI will be not only in-person but held in the charming seaside city of St Andrews, Scotland. More details at disi.org. The application window is only open for a little while longer, so better act fast.  Alright friends, on to my chat with Dr. Marina Bedny. Enjoy!   A transcript of this episode is available here.   Notes and links 3:30 ­– A popular article and video on the ideas of John Locke and other empiricists. 4:50 – One of the original articles by the philosopher Frank Jackson on Mary the color scientist. 7:35 – The 1985 book by Dr. Barbara Landau and Dr. Lila Gleitman on language acquisition in (a few) blind children. 11:00 – Dr. Bedny’s first study involving blind subjects, in collaboration with Dr. Alvaro Pascual-Leone and Dr. Rebecca Saxe. 15:00 – A recent study in Dr. Bedny’s lab, led by Dr. Judy Kim, comparing color knowledge in blind and sighted adults. 23:30 – A recent study by Dr. Bedny and collaborators on blind people’s understanding of visual verbs like sparkle, glow, peek, and stare. 30:30 – A recent study in Dr. Bedny’s lab, led by Dr. Judy Kim, comparing knowledge of animal appearance in blind and sighted adults. 34:00 – Tour an interactive model of the visual cortex—and the rest of the brain—here. 36:00 – A now-classic paper by Dr. Norihiro Sadato and colleagues on how reading Braille activates blind people’s “visual” cortex. 37:30– The “metamodal” hypothesis and the “pluripotent” hypothesis are compared in Dr. Bedny’s recent article in TiCs. 45:30 – A 2011 paper by Dr. Bedny and colleagues about how, in blind people, the “visual” cortex is involved in language processing. 49:00 – A paper showing that “visual” areas in blind people are highly synchronized when listening to stories. A more recent paper in a similar vein. 53:00 – A now-classic paper by Dehaene and Cohen on the “cultural recycling” of certain brain areas. 56:00 – A paper by Dr. Bedny and colleagues on sensitive periods and cortical specialization. 1:01:00 – A recent paper from Dr. Bedny’s lab, led by Karen Arcos, showing superior verbal working memory in blind relative to sighted adults. 1:03:30 – Another study from Dr. Bedny’s lab showing that blind people are less likely than sighted people to be led astray by garden-path sentences.   Dr. Bedny recommends: Her TiCs article on the “pluripotent cortex” Recent papers (e.g. here and here) from her lab led by Dr. Judy Kim A now-classic paper on cortical recycling.   You can read more about Dr. Bedny’s work at her lab’s website.   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 Cecilia Padilla. Creative support is provided by 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 to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you like to listen to podcasts. 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.