The role of the sound of tapping for nonvisual judgment of gap crossability

The author investigated the possibility that nonvisual locomotion with a ca ne depends on the sound of the cane tapping. Blindfolded participants were asked to judge whether a gap in front of them could be crossed by walking. An acoustic analysis suggested that sound could, in theory, distinguish the gaps. Blindfolded sighted participants in Experiments 1 and 2 judged cross ability under conditions in which only the sound of tapping was available a nd in which the sound was minimized; the third and fourth experiments inclu ded experienced cane users. Both inexperienced observers and experienced ca ne users were unaffected by sound reduction and were less able to discrimin ate gaps when using sound only than when using reduced sound. A fifth exper iment indicated that active-passive differences were not responsible for th ese effects. Results indicate that sound is not necessary or sufficient for judging nonvisible crossability with a probe.