ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

3aPP15. Auditory detection of changes in mass density and elasticity of a tuning fork.

Robert A. Lutfi

Eunmi Oh

Dept. of Commun. Disord. and Psych., Univ. of Wisconsin, Madison, WI 53706

The principles of theoretical acoustics were applied to reconstruct the sound-pressure waveform at the ear as would be generated by an idealized tuning fork (struck, clamped bar). The result is an inharmonic sum of damped sinusoids whose individual acoustic parameters (frequency, intensity, and decay modulus) are determined by the mass density and elasticity of the material comprising the bar. In the standard 2IFC procedure, listeners were asked, in effect, to detect changes in the material composition of the bar based on their perception of the acoustic waveform. Listener strategies for detecting such changes were estimated by perturbing slightly the individual acoustic parameters from trial to trial and computing correlations with the listener's response [cf. R. A. Lutfi and E. Oh, 2963(A) (1994)]. In general, the correlations revealed that listeners fail to make optimal use of the information in the acoustic waveform by tending to give undue weight, for a given material change, on one or more parameters of the acoustic waveform. The results are discussed in terms of their implications for ecological notions regarding the perception of ``higher-order'' variables in the determination of natural resonant sources. [Research supported by NIDCD.]