Use of Musical Scales to Display Distance to Objects in an Electronic Travel Aid for the Blind

An electronic travel aid for the blind has been designed which displays distance to objects in terms of the eight notes of the musical scale. Experiments are described which determine the relationship between the efficacy of various tonal displays and the musical sophistication of the subjects. In particular it is shown that the accuracy of predicting the end of a scale, and hence a collision with an object, is a function of familiarity with the scale. That this accuracy is a function of musical sophistication receives only partial support. As expected, the ascending and descending versions of a scale are, in general, equally effective but, unexpectedly, the hypothesis that the accuracy of predicting the end of a tonal sequence would be an inverse function of the sequence length is confirmed only in the case of one scale, the Ionian or Major scale.