A study of the discriminability of shape symbols by the foot

An experiment to test the discriminability of shape symbols using the shod foot was performed with 38 blind people (aged 23-72 years). Ten shape symbo ls which were 5 mm thick and fitted into a 30.5 cm(2) tile were presented t o subjects to identify by using only their feet. Each subject had 20 trials in which to discriminate the symbols. In each trial, a symbol was selected randomly and presented to the subject in randomized orientation. The subje ct was instructed to step on the symbol and to identify it using their own method. Time to discriminate a symbol and the accuracy of identification we re recorded. A very high accuracy (93% on average) was obtained, which is c omparable to the accuracy of tactile symbol discrimination using the hands. Average time to discriminate a symbol was 16 s with a standard deviation o f 12.15 s, which indicated the high variability of the results. Owing to th e high accuracy of identification, tactile foot-discriminable symbols have great potential as landmarks for blind people and if applied to a tactile g uide path they could provide information for orientation and navigation.