Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references.One of the great puzzles of vision science is how, over the course of development, the complex visual array comprising many regions of different colors and luminances is transformed into a sophisticated and meaningful constellation of objects. Gestaltists describe some of the rules that seem to govern a mature parsing of the visual scene, but where do these rules come from? Are they innate--endowed by evolution, or do they come somehow from visual experience? The answer to this question is usually confounded in infant studies as the timelines of maturation and experience are inextricably linked. Here, we describe studies with a special population of late--onset vision patients, which suggest a distinction between those capabilities available innately and those which are crafted via learning from the visual environment. We conclude with a hypothesis, based on these findings and other evidence, that early-available common fate motion cues provide a level of perceptual organization which forms the basis for the learning of subsequent cues.by Yuri Ostrovsky.Ph.D.