Temporal factors in auditory peak detection of modulation of tones

• Published in: The Journal of the Acoustical Society of America 1999-10, Vol.106 (4_Supplement), p.2147-2147
• Main Authors: Goldstein, Julius L., Hall, Joseph L.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.427343

Auditory detection of tone modulation has been modeled as envelope-peak detection of the cochlear filterbank responses [J. L. Goldstein, J. Acoust. Soc. Am. 41, 458–479 (1967)]. To study the ability of this model to quantify temporal smoothing in detection, new psychophysical experiments using a 4IFC paradigm were conducted, with the authors as subjects. AM or quasi-FM sinusoidally modulated tones were discriminated from the carrier tone. Only one should was modulated among the four pushed sounds in the paradigm. The first series of exploratory experiments (1994) focused on low modulation frequencies (4–16 Hz). A second series of systematic experiments (1996) with a wide range of modulation frequencies allowed estimation of detector smoothing at carrier frequencies of 0.25, 1, and 4 kHz. Despite differences between subjects in estimated spectral filtering, modulation thresholds for both subjects gave similar estimates of smoothing at each carrier frequency. At modulation frequencies above 20 Hz, the smoothing function showed similar dependence on carrier frequencies as found from the early experiments (1967). Below 20 Hz, the early experiments, which used a method of adjustment paradigm, reveal a hyperacuity. This suggests a second slower detection mechanism that exploits repeated presentations of test sounds. [Work supported by NSF Grant IBN-9728383.]