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A Two-interval Forced-choice Task for Multisensory Comparisons
Published on: November 9, 2018
Octave illusion elicited by overlapping narrowband noises
K Jonas Brännström1, Patrik Nilsson
1Department of Clinical Science, Section of Logopedics, Phoniatrics and Audiology, Lund University, SE-221 85 Lund, Sweden.
The Journal of the Acoustical Society of America
|May 17, 2011
Summary
The Deutsch illusion, involving alternating tones between ears, can be triggered by complex noises. The illusion
Area of Science:
- Auditory Perception
- Psychoacoustics
- Neuroscience
Background:
- The Deutsch illusion demonstrates how the brain processes auditory information, specifically pitch and spatial location.
- This illusion typically involves alternating tones presented to different ears, leading to a perception of a single, pitch-alternating sound.
- Previous research has primarily used pure tones to elicit this auditory phenomenon.
Purpose of the Study:
- To investigate if aperiodic signals, specifically band-pass filtered noises, can induce the Deutsch illusion.
- To examine the influence of varying spectral content (high- and low-frequency) on the perception of the illusion.
- To determine if the illusion's salience is affected by the frequency characteristics of the noise stimuli.
Main Methods:
- Subjects were presented with low-frequency band-pass filtered noises with overlapping spectra.
- The spectral overlap was constant, while the high- and low-frequency components of the noise were systematically manipulated.
- Participants reported their auditory experiences, focusing on pitch perception and sound lateralization.
Main Results:
- A majority of subjects perceived an auditory illusion similar to the Deutsch illusion, with a dominant ear for pitch and frequency-based lateralization.
- The salience of the perceived illusion increased with higher frequency content in the noise signals.
- The absence of harmonics in the stimuli suggests the illusion is not due to binaural diplacusis or harmonic fusion.
Conclusions:
- The Deutsch illusion can be elicited using complex, aperiodic noise signals, extending beyond pure tones.
- Frequency content significantly influences the strength and perception of the auditory illusion.
- These findings provide further insight into the neural mechanisms underlying auditory scene analysis and sound localization.
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