Fadhil M. Alibrahim
Someone who was born blind experiences sounds, smells, and sensations while dreaming, but since the brain possesses no visual information, the dreams are not visual, says Charles Crawford, executive director of the American Council of the Blind. A blind person's brain might combine sensory information into a representational image of an object, but that image would bear little resemblance to the object itself.
By contrast, people who become blind as children or adults do have visual dreams, but their dream images depict the world as it appeared around the time they lost their sight. "I lost my vision by the time I was 22," says Crawford. "When I have visual dreams, the images are of the world before the 1960s."
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.