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 symbols which were 5 mm thick and fitted into a 30.5 cm2 tile were presented to 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 subject 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 were recorded. A very high accuracy (93% on average) was obtained, which is comparable to the accuracy of tactile symbol discrimination using the hands. Average time to discriminate a symbol was 16 s with a standard deviation of 12.15 s, which indicated the high variability of the results. Owing to the high accuracy of identification, tactile foot-discriminable symbols have great potential as landmarks for blind people and if applied to a tactile guide path they could provide information for orientation and navigation.