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Richard Held, Yuri Ostrovsky, Beatrice deGelder, Pawan Sinha; Revisiting the molyneux question. Journal of Vision 2008;8(6):523. doi: 10.1167/8.6.523.
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Three hundred years ago the Irish philosopher-scientist William Molyneux wrote to his friend, the philosopher John Locke the following letter: “Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere of the same metal … Suppose then the cube and sphere placed on a table, and the blind man be made to see: query, whether by his sight, before he touched them he could now distinguish and tell which is the globe, which the cube …?” This question, which bears on important issues of shape representation and cross-modal communication, has so far remained unanswered. Addressing it entails finding appropriate subjects—congenitally blind from occlusive pathology such as cataract or other opacity. The visual system from retina centrally must be functional so that clear optics and hence vision are potentially recoverable by state of the art medical procedures. These must be followed as soon as possible, ideally immediately, by appropriate testing of transfer of object discrimination from vision to touch and vice versa. Patients must be mature enough to be capable of reliable discrimination testing. Project Prakash (Nature, 2006, vol. 441, 271–272) has provided us an opportunity to work with such patients. We report here experiments with two individuals. Our results suggest a complete lack of transfer from normal tactile discrimination to vision immediately after sight onset. Interestingly, however, we find evidence for touch to vision transfer and of cross-modal recognition, about a week after surgery. The mechanisms of such rapid learning are currently unknown.
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