'Octave illusion' or 'Deutsch's illusion'?

摘要

The "Deutsch's illusion" occurs in most peoplewhen a dichotic pair of tones spaced an octave apart is pre-sented repeatedly in alternation, so that when the right earreceives the high tone, the left ear receives the low tone,and vice versa. The illusory percept consists typically in asingle low tone heard at one ear alternating with a singlehigh tone heard at the other ear. Here, we investigatewhether the frequency interval between the tones and theirduration play a role in the perception of the illusion. Bytesting 74 subjects we demonstrate that the illusion is notconfined to tones spaced an octave apart but it is perceiv-able also with tones separated by a major seventh, a minorninth, a major ninth, and a minor tenth. Regarding duration,the present results show that the illusion is stronger withtones lasting 500 than 200 ms. The present results suggestthat the perceptual mechanisms at the basis of the illusionare not strictly linked to the frequency relationshipsbetween the dichotic tones.