I have a mental problem. Ok, I have several, but in particular I have trouble with navigation, with finding my way around even familiar places. On a regular basis my wife asks me to run an errand and I have to admit I have no idea where I'm supposed to go. "But we've been there a dozen times," she says, exasperated. It doesn't matter, especially if she was one the doing the driving (which, because of this problem, she often is). There's a slightly better possibility that if I've driven somewhere in the past that I'll remember the way, and an even better, if still small, chance that I can find my way somewhere that I've walked or bicycled to. But, usually, it's hopeless. It took me nearly a year of practice to be able to comfortably drive from my own house to my in-laws, a distance of eighteen miles and involving only four turns. Thankfully, I have GPS on my phone, and I'm strangely ok at reading and following maps, which I consult often, sometimes even to get around the neighborhood in which I've lived for twelve years.
Now, thanks to reading Oliver Sacks' The Mind's Eye, I have a name for my condition. It's called topographical agnosia and I share it with Dr. Sacks himself and Jane Goodall, among many others. It's a condition that often accompanies the far more perplexing problem of face-blindness (thankfully, I don't have face blindness). People with face blindness, or prosopagnosia, have trouble recognizing anyone, even members of their own family, based on their faces alone. All faces, and places, look unfamiliar to those with prosopagnosia, and often result in odd behaviors, like hugging a complete stranger that face blind person mistakes for a loved one. An essay on face blindness, and Dr. Sacks' own experiences in dealing with his condition, is one of the central pieces collected in The Mind's Eye. It is written in Sacks' personal, comfortable style that makes you forget you're taking in multi-syllabic terms like "topographical agnosia" even as it dumbs down nothing.
The Mind's Eye concerns itself with vision, which, in humans and most higher animals, has two elements that must function well and in sync: the eyes and the brain. Obviously, if something goes wrong with the eyes, vision will be impaired. But equally important is the processing of visual information, which occurs in the brain. And when things go wrong in the brain's visual center(s) the effects can be equally troubling and often far more bizarre.
In the books opening essay, Dr. Sacks treats a patient who suddenly becomes unable to read words or printed music (a particular problem since she is a concert pianist by trade). She is able to identify letters. They are crisp and clear to eyes, but their meaning is lost. Paradoxically--and mind-blowingly--she is still able to write. But she is then unable to read anything she has written as soon as she has written it. The simple fact that reading and writing occupy different centers, and are distinctly different processes in the brain is just one of the revelations that The Mind's Eye has in store for its readers.
The book moves from essays on the visual center of the brain to the issues of damaged eyes and, finally, to blindness. Sacks reveals a journal he kept from a period in which a tumor claimed most of the vision in his right eye and robbed him of depth perception. He introduces us to the strangely rich world of sense that the blind experience and to a surgeon and engineer whose mind utterly lacks visual imagery. Taken together the book will open your eyes to the processes of the mind and open your mind to the strange world of sight.
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