Frequency selectivity under diotic and dichotic listening conditions

Abstract

Results of several experiments on binaural hearing suggest that the auditory filter employed in MLD producing conditions is wider than that used under diotic or monaural listening conditions. The present experiment tests this hypothesis using Greenberg and Larkin's probe frequency technique. [J. Acoust. Soc. Am. 44, 1513–1523 (1968)]. Subjects were first trained in the detection of a 500-Hz tone and psychometric functions were obtained for NOSO and NOSπ masking conditions. In the next part of the experiment, and unknown to the subjects, probe frequencies both higher and lower in frequency than 500 Hz were substituted for the primary signal with a probability of 0.25. Performance at each probe frequency was then converted to an equivalent amount of attenuation in decibels, via the psychometric functions, and corrected for changes in the MLD with frequency. Resulting filter characteristics will be discussed in terms of the hypothesis that the filter for the binaural system is wider than that for the monaural system.