The Creation, Presentation and Implications of Selected Auditory Illusions

This report describes the initial phase of a project whose goal is to produce a rich acoustic environment in which the behaviour of multiple independent activities is communicated through perceptually distinguishable auditory streams. While much is known about the perception of isolated auditory phenomena, there are few general guidelines for the selection of auditory elements that can be composed to achieve a display that is effective in situations where the ambient acoustic conditions are uncontrolled. Several auditory illusions and effects are described in the areas of relative pitch discrimination, perception of auditory streams, and the natural association of visual and auditory stimuli. The effects have been evaluated informally through a set of demonstration programs that have been presented to a large and varied audience. Each auditory effect is introduced, suggestions for an effective demonstration are given, and our experience with the demonstration program is summarized. Implementation issues relevant to the reproduction of these effects on other platforms are also discussed. We conclude by describing several experiments aimed at resolving issues raised by our experience with these effects.