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

2pPP45. Binaural detection with reproducible narrow-band maskers.

Scott K. Isabelle

H. Steven Colburn

Dept. of Biomed. Eng., Boston Univ., 44 Cummington St., Boston, MA 02215

Responses of five subjects for the binaural detection of a 500-Hz, 300-ms, interaurally out-of-phase tone masked by statistically independent samples of narrow-band, interaurally identical noise are reported. A set of 30 noise samples were taken from a noise process with a power spectrum that is 115 Hz wide, centered at 500 Hz. The rms noise pressure was 75 dB SPL. For each subject, the responses show good self-consistency and a strong dependence on individual noise samples. (For example intrasubject correlation coefficients for subsets of the results were typically 0.85 and always higher than 0.72). However, there are significant differences between subjects in the pattern of responses across the set of masker samples. (Intersubject correlation coefficients were lower than 0.7). Subjects' performance values for individual noise samples are compared to the predictions of psychophysical models for binaural detection. Sample-level predictions of models for which the decision variable is dominated by the energy in the particular noise sample have no significant correlation with the patterns of responses across noise samples for any subject. In contrast, models that are based on variability of the interaural differences have predictions that are statistically significantly correlated with most subjects' responses (although no correlation coefficients were larger than 0.7). [Work supported by NIDCD (Grant DC00100).]