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How Brains Know Where Things Are—Making Space by Jennifer Groh

Groh launches her book with a BIG FAT LIE: she tells us that nine-tenths of our brain power is spent determining where things are. Then she immediately admits that she just made that up, but that she'd dedicate the rest of the book to explaining why she thinks its true.

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


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This year’s Nobel Prize for Medicine or Physiology went to John O'Keefe (University College London) and May-Britt & Edvard Moser (Norwegian University of Science and Technology) for discoveries concerning how the brain knows where we are in space: our mind's GPS. But the flip side to knowing where we are is knowing what space is--as a concept. How is it that our brains create the perception of space itself? Where is every object in our world, with respect to us and to every other thing? That's the topic of the new book Making Space, by neuroscientist Jennifer Groh (Duke University).

How do we localize distance positions of objects with our vision? The book tells us what is known, and lays out the necessary background--such as the basic neuroscience of vision--needed to understand the larger concept. Groh also tackles how we localize objects with more than just our vision. We can close our eyes and localize sound-producing objects with our ears. Helen Keller, to further this point, had neither hearing nor vision but could localize objects in space--as most of us can--through reaching and touching. This book is about that too (not the Helen Keller part, but, you know, the understanding-space-through-touch part). Tommy Walker (of The Who fame) could play pinball by sense of smell, and by every accounting he was a wizard: he always got the replay, and never tilted at all… that deaf, mute, and blind kid, sure played a mean pinbaaaaalllll! Dramatic…. but I hope you see the point of this fictitious example: Groh's book describes the general process by which the brain conceives of space in a highly unconventional and entertaining stream of Jennifer Groh's consciousness. She jumps from one musing to the next. Not in a random walk, but in a meandering though rational thought process that feeds the readers the information they need only when they need it, and not before.


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The facts are not laid out like a regular text book. It doesn't start with phototransduction in the eye, followed by the functional anatomy of the retina, followed by a description of the early parts of the visual brain, then of the higher cortical areas, etc. That's all well and good and orderly. That's what makes for a nice reference in which to look things up. But it's not how a scientist thinks and it's not the order by which things get discovered. Science is much messier--and much more interesting-- than that. Instead Groh goes right for the throat. She launches her book with a BIG FAT LIE: she tells us that nine-tenths of our brain power is spent determining where things are. Then she immediately admits that she just made that up, but that she'd dedicate the rest of the book to explaining why she thinks its true. I was hooked! Brilliant, tantalizing, probably correct, but maybe not! I knew right then I would read this book cover-to-cover.

This back and forth--between hard scientific fact and the educated guessing of a trained master neuroscientist--which at first may seem jarring but which eventually gels together nicely, is one of the best things about the book. It lays out a fascinating field of inquiry (which is really multiple fields interwoven convincingly, filtered by Groh's own thought processes) in a way that shows how a proper scientist thinks. And I don't mean scientists as a whole (though few scientists' thought processes are as interesting or as robust as Groh's). No, this book tells it as Groh sees it. You see exactly how she and her colleagues in her field approach the problem of integrating sensory and cognitive information to give us all a place within which to live our lives. A place where we are rarely lost and almost never have to puzzle out how to find our dinner, our mates, or our kids.

Stephen L. Macknik is a professor of opthalmology, neurology, and physiology and pharmacology at SUNY Downstate Medical Center in Brooklyn, N.Y. Along with Susana Martinez-Conde and Sandra Blakeslee, he is author of the Prisma Prize-winning Sleights of Mind. Their forthcoming book, Champions of Illusion, will be published by Scientific American/Farrar, Straus and Giroux.

More by Stephen L. Macknik