How Do Blind People Picture Reality?

Paul Gabias has never seen a table. He was born prematurely and went blind shortly thereafter, most likely because of overexposure to oxygen in his incubator. And yet, Gabias, 60, has no trouble perceiving the table next to him. “My image of the table is exactly the same as a table,” he said. “It has height, depth, width, texture; I can picture the whole thing all at once. It just has no color.”

If you have trouble constructing a mental picture of a table that has no color — not even black or white — that’s probably because you’re blinded by your ability to see. Sighted people visualize the surrounding world by detecting borders between areas rich in different wavelengths of light, which we see as different colors. Gabias, like many blind people, builds pictures using his sense of touch, and by listening to the echoes of clicks of his tongue and taps of his cane as these sounds bounce off objects in his surroundings, a technique called echolocation.

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