Perceptual learning is defined as the improvement of the performance on perceptual tasks after training. Perceptual learning of human visual system has been widely investigated. Previous studies on perceptual learning were focused on its specificity and generalization. In some visual tasks, such as retinal location, spatial frequency or orientation, the learned performance is limited to the specific stimulus. In other visual tasks, the improved performance can be transferred to different stimuli or tasks. Specificity and generalization can be viewed as two the ends of a transferability continuum, on which each task may have a specific position (or value). Neurophysiological findings suggest that perceptual learning of different complexities may involve different levels of visual cortical processing, and the neural mechanism involved may depend on the feature ( e. g. , the complexity) of the stimulus in the task. Perceptual learning can be divided into fast learning and slow learning. A number of studies have used ERP and other brain imaging techniques to investigate the neural mechanism of visual perceptual learning under different time scales. Age-related macular degeneration (AMD) afflicts about one out of ten Americans aged over 80 years. The patients often feel bilateral central scotoma, because AMD damaged their fovea. Because reading is slow and difficult for these patients, they have to use their peripheral retina. In order to help these patients improve their reading, many studies focused on perceptual learning of peripheral vision. A study suggests that training on a letter-recognition task would lead young adults to improve reading speed in peripberal vision, and this learning effect would transfer to an untrained retinal location. For old adults, research showed that reading speed also improved in the trained field, but the training benefits for these old adults were weaker than the training benefits for young adults. Perceptual learning is still a potential method for low-vision reading rehabilitation among older adults, even though the training benefit is less. Some studies suggested a link between reading speed and the size of the visual span. Visual span means the number of characters that can be recognized on a single fixation. It is a bottleneck on reading speed, but it can be increased with practice. A study about comparing reading speed for vertical and horizontal English text using RSVP and flashcard ( a block of text on four lines) showed that reading speed for horizontal text was faster. The size of the visual span was highly correlated with reading speed, both for RSVP and flashcard reading. It showed that slower reading of vertical text was due to a decrease in the size of the visual span for vertical reading. The RSVP reading and lexical-decision might plausibly produce more improvement in peripheral reading speed. Chinese characters are important for the Chinese readers. The perceptual learning of peripheral vision in reading Chinese characters is an interesting research field of great value, but the paradigm needs to be improved.
NETL
NSTL
万方数据
维普
