Central and peripheral influences on tactual reading

Subjects attempted to read two-, three-, or four-letter words printed on their palms, wrists, or fingers. Successive letters were either drawn over each other at the same location or were spatially separated on skin surfaces. A peripheral source of masking was suggested, since reading was aided by writing letters at different cutaneous locations. Two-letter words were easy to read when two palms or the palm and wrist were used. Due to interdigit masking, however, spatial separation of letters did not help when they were printed on the fingers of one hand. Central contributions to tactual reading were indicated, since categorical information aided reading, as did knowledge of (constant) orientation. The difficulties found in reading Print-On-Palm (POP) were ascribed to aftersensations derived from drawing a point across the skin, a passive form of touch. It was proposed that passive touch may be limited in performance when memory is severely loaded. However, passive touch may suffice for simple patterns, since passive POP was better than active touch for letter recognition.