Braille in the Sighted: Teaching Tactile Reading to Sighted Adults

International audienceBlind people are known to have superior perceptual abilities in their remaining senses. Several studies suggest that these enhancements are dependent on the specific experience of blind individuals, who use those remaining senses more than sighted subjects. In line with this view, sighted subjects, when trained, are able to significantly progress in relatively simple tactile tasks. However, the case of complex tactile tasks is less obvious, as some studies suggest that visual deprivation itself could confer large advantages in learning them. It remains unclear to what extent those complex skills, such as braille reading, can be learnt by sighted subjects. Here we enrolled twenty-nine sighted adults, mostly braille teachers and educators, in a 9-month braille reading course. At the beginning of the course, all subjects were naive in tactile braille reading. After the course, almost all were able to read whole braille words at a mean speed of 6 words-per-minute. Subjects with low tactile acuity did not differ significantly in braille reading speed from the rest of the group, indicating that low tactile acuity is not a limiting factor for learning braille, at least at this early stage of learning. Our study shows that most sighted adults can learn whole-word braille reading, given the right method and a considerable amount of motivation. The adult sensorimotor system can thus adapt, to some level, to very complex tactile tasks without visual deprivation. The pace of learning in our group was comparable to congenitally and early blind children learning braille in primary school, which suggests that the blind's mastery of complex tactile tasks can, to a large extent, be explained by experience-dependent mechanisms

Outline of the study and timeline of the braille course.

<p>(A) Sighted adults underwent a 9-month braille course. They were tested behaviorally in the baseline testing session, four times during the course (i.e., in the 5^th, 6^th, 7^th and 8^th month of the course) and after the course. (B) The braille course consisted of three stages: tactile discrimination exercises, introducing half of the braille alphabet and learning the remaining half/whole-word reading.</p

Sighted adults can learn whole-word braille reading.

<p>(A-B) Results of braille word reading test and braille letter reading test. Average number of braille words/letters read in one minute was plotted for each testing session. (C) Individual learning curves for braille word reading, plotted based on results of braille word reading test in each testing session. (D) Correlation between the tactile acuity (grating orientation threshold) at the end of the course and final braille word reading speed. Error bars represent 95% confidence intervals. Asterisks indicate a significant difference between the results of a specific testing session and a baseline testing session (*** p < 0.001).</p