The effect of orientation on visual and tactual braille recognition.

Five experiments are reported in which subjects matched tangible or visible braille characters against either visual or tangible arrays. In both modalities recognition was impaired when the characters were tilted, but visual performance was superior to that for touch. Touch may be more sensitive than vision to tilt, since very small deviations from the upright decreased recognition accuracy. Orientation influenced pattern recognition with and without prior information about orientation. Tilting patterns slowed down recognition for tactual-visual matching, but only when orientation was studied with repeated measures. The results are consistent with the hypothesis that it is difficult to code braille patterns tactually as global outline shapes.