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Intensity discrimination under forward and backward masking: role of referential coding
C J Plack1, R P Carlyon, N F Viemeister
1Laboratory of Experimental Psychology, University of Sussex, Brighton, England.
The Journal of the Acoustical Society of America
|February 1, 1995
Summary
Listeners can improve sound intensity discrimination by referencing nearby sounds, even when masked. This study shows auditory coding improves with shorter intervals between sounds, suggesting a sophisticated referencing mechanism.
Area of Science:
- Auditory Perception
- Psychoacoustics
- Signal Processing
Background:
- Intensity discrimination is crucial for auditory perception.
- Nonsimultaneous masking presents challenges to auditory processing.
- The role of proximal stimuli in auditory coding remains an area of investigation.
Purpose of the Study:
- To test the hypothesis that listeners code sound intensity by referencing proximal stimuli.
- To investigate how nonsimultaneous masking affects intensity discrimination.
- To explore the auditory system's ability to use proximal signals for robust intensity measurement.
Main Methods:
- Experiments utilized 30-ms tone bursts as masker, pedestal, and proximal bursts.
- Varied the silent interval between masker and pedestal (100 to 12.5 ms).
- Introduced an additional proximal burst before or after the pedestal with varying frequency and intensity.
Main Results:
- Weber fraction decreased as the silent interval shortened in both forward and backward masking.
- A proximal burst significantly decreased the Weber fraction when close in frequency and higher in intensity.
- Performance improvements suggest intensity is coded relative to proximal masker levels.
Conclusions:
- The auditory system can generate a robust intensity measure by referencing proximal signals.
- Short temporal intervals enhance intensity discrimination through referential coding.
- Findings challenge solely auditory nerve-based explanations for forward masking effects.