Rapid development of reaching/grasping and intersensory recognition in a previously blind Tibetan girl

Abstract

On a charity mission we discovered a 44 month-old Tibetan girl who was blind due to dense bilateral congenital cataracts. We report here the results of video-recorded experiments on the child immediately after post cataract surgery eye patch removal: looking and reaching/ grasping responses during the first hour and crossmodal object recognition during the next 5 days. These tasks all involve different aspects of linking visual and tactile sensory information together. At first sight, she looks aimlessly around, at 5 min she discovers her hand, next she starts looking at objects in front of her, at 12 minutes she starts reaching and grasping for objects and by 24 minutes she does this with good accuracy. She has continuously recalibrated her movements using sensory feedback signals until she could accurately reach for and grasp objects. The next day we tested object recognition with single vs a triple length LEGO blocks. First, a block was placed in her hand for her to see and feel simultaneously. Then in a paired comparison she chose by vision alone the correct LEGO almost perfectly. If she only saw a LEGO and then chose by sight or touched a LEGO and then chose by either touch or sight alone, she performed at chance. On the following day she recognized the correct LEGO in all three procedures. With a more difficult comparison (double vs triple LEGO) she was above chance (90%) with sight-to-sight but at chance with the other two comparisons. On day 5, she performed perfectly on sight-to-sight and the intermodal touch-to-sight with touch-to-touch still at chance. Recognition performance was the same when comparing a cube vs same size cylinder. These data indicate that the visual system is preprogrammed to quickly learn to visually recognize objects even if they were only touched initially.

Meeting abstract presented at VSS 2017