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Intensity resolution and loudness in broadband noise
R S Schlauch1, S Harvey, N Lanthier
1Department of Communication Disorders, University of Minnesota, Minneapolis 55455, USA.
The Journal of the Acoustical Society of America
|October 1, 1995
Summary
This study investigated how noise affects loudness perception and intensity resolution in humans. Models predicting these effects were tested, finding that some models align with data when noise-induced changes in perception are considered.
Area of Science:
- Auditory perception
- Psychoacoustics
- Hearing science
Background:
- Understanding loudness perception and intensity resolution is crucial for audiology and hearing aid development.
- Existing models attempt to link intensity discrimination (Weber functions) with loudness perception, but their accuracy in noise is debated.
Purpose of the Study:
- To evaluate several psychoacoustic models by examining intensity resolution and loudness matching in quiet and noise.
- To determine how different noise levels affect the relationship between intensity resolution and loudness perception.
Main Methods:
- Five normally hearing listeners performed loudness matching and intensity resolution tasks in quiet and two noise conditions (15 and 40 dB spectrum level).
- Weber functions and loudness matching functions were analyzed, and modified power functions were fitted to estimate the loudness function exponent.
- Three models predicting Weber functions from loudness were tested against the experimental data.
Main Results:
- Weber functions were elevated in noise compared to quiet at equal sound pressure levels (SPLs).
- Loudness matching functions exhibited a slope greater than unity, indicating altered loudness perception in noise.
- The neural counting model and proportional-jnd theory successfully predicted Weber functions when accounting for changes in decision variable variance in noise.
Conclusions:
- The subjective analog to Weber's law was inconsistent with the observed data.
- The neural counting model and proportional-jnd theory provide a viable framework for understanding intensity resolution and loudness perception in noise.
- Further research is needed to elucidate the physiological mechanisms underlying the proportional-jnd theory's success in explaining auditory perception in noise.