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Roughness perception in sounds: behavioral and ERP evidence.
Wouter De Baene1, André Vandierendonck, Marc Leman
1Department of Experimental Psychology, Ghent University, Ghent, Belgium. wouter.debaene@med.kuleuven.ac.be
Biological Psychology
|August 6, 2004
Summary
Mismatch negativity (MMN) reflects preattentive encoding of sound roughness. Brain responses correlate with perceived roughness, not just physical sound properties, indicating early sensory processing.
Area of Science:
- Auditory Neuroscience
- Psychoacoustics
- Cognitive Neuroscience
Background:
- Roughness is an unpleasant sound quality linked to amplitude fluctuations (20-200 Hz).
- The modulation index (m) is a key parameter influencing perceived roughness.
Purpose of the Study:
- To investigate the mismatch negativity (MMN) correlates of sound roughness perception.
- To determine if MMN reflects perceived roughness or its physical acoustic parameters.
Main Methods:
- A psychophysical study measured roughness perception across varying modulation indices (m).
- An event-related potential (ERP) study recorded MMN responses to amplitude-modulated (AM) tones in an auditory oddball paradigm.
Main Results:
- Perceived roughness increased with modulation index up to m=1.2, then plateaued.
- MMN amplitude showed a high negative correlation with roughness ratings (r = -0.93).
- MMN amplitude did not monotonically increase with the modulation index.
Conclusions:
- MMN reflects the subjective perception of sound roughness, not just the physical modulation.
- Roughness is encoded preattentively in the brain, as indicated by MMN responses.