ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
3aPP16. Peak detection for auditory sound discrimination.
Julius L. Goldstein
Central Inst. for the Deaf, 818 S. Euclid, St. Louis, MO 63110-1594
Joseph L. Hall
AT&T Bell Labs., Murray Hill, NJ 07974-0636
Auditory detection of envelope maxima in temporal responses of cochlear
frequency-analyzing filters has been hypothesized to account for phase effects
in psychophysical discrimination [J. L. Goldstein, 458--479 (1967)].
Re-examination of this hypothesis in the context of asymmetry of masking [R.
Hellman, Percept. Psychophys. 11, 241--246 (1972)] reveals that it also
provides an adequate explanation for this phenomenon. Peak discrimination
between a tone and tone masker plus narrow-band-noise probe is more sensitive
to probe energy than is the inverse discrimination between noise and noise
masker plus tone probe, in agreement with psychophysics. Simulations of this
model indicate that asymmetry of masking is a function of the product of noise
bandwidth and temporal duration. Psychophysical experiments on masking
asymmetry were performed with both masker and probe bandwidth ranging from pure
tone to supracritical band. The experimental design included both fixed and
roving levels, with random phases fixed throughout each experiment. A standard
detection-theory model was fit to the data, assuming that ratios of peaks or of
normalized peaks are measured by an optimal noisy discriminator. Predictions
based upon stimulus envelopes are in good agreement with the data.