台大心理系

Newborns can see but there are serious limitations on their vision. We have investigated the role of visual experience in driving the many, protracted visual changes. We have done so by taking advantage of a natural experiment: children born with dense cataracts in one or both eyes that blocked all patterned visual input until the cataracts were removed during infancy and the eyes given compensatory contact lenses. Even when the babies missed only a few months of visual input, they later develop a host of deficits in both low-level (e.g., acuity, peripheral vision), and highlevel (e.g., perceiving the direction of motion, face processing) vision. For low-level vision, the deficits are worse in the deprived eye when the deprivation was monocular rather than binocular, a pattern suggesting that the visual nervous system is tuned during early infancy not only by patterned visual input but also by the balance of input between the right and left eyes. Surprisingly, for high-level vision, the deficits are smaller after monocular than after binocular deprivation. To understand this
paradox, we are exploring the possible re-organization of hearing in the cataract patients and how its interaction with vision may differ between bilateral and unilateral patients. Overall, the results indicate that perceptual development is perturbed by imbalances, be they between the eyes or between the senses. Nevertheless, there is residual plasticity in adulthood that allows some recovery.