Space and sight: the perception of space and shape in the congenitally blind before and after operation

Historical Significance: Marius von Senden was so fascinated with the problems faced by newly sighted adults that he researched every known case (66 cases) over a three hundred year stretch of history, right back to the time when John Locke first posed a hypothetical question in a 1690 essay. A person who had been born blind, Locke knew, could learn to distinguish between a cube and a sphere by touch. If he suddenly became able to see, would he recognize the cube and the sphere by sight? Locke didn't think so. When Sacks' patient became able to see, he couldn't tell his cat from his dog without feeling them. Von Senden's research led him to conclude that such people invariably face a "motivation crisis". To learn to see is overwhelmingly difficult, and there is a temptation to revert to blindness, where one knows how to cope. Not every patient makes it through this stage. Originally published in German as Raum- und gestaltauffassung bei operierten blindgeborenen vor und nach der operation, Leipzig, J. A. Barth, 1932.