Effect of Contralateral Broad-band Noise on Frequency Discrimination

Abstract

The effect of contralateral masking on a person's ability to detect small changes in frequency was studied. Eight normal-hearing young adults with no previous participation in psychoacoustic experiments served as subjects. The task consisted of matching the frequency of a variable signal (3 575-4 425 Hz) to that of the reference tone (4 000 Hz) by the method of adjustment. As many tone pairs as necessary to complete the judgment were presented in a fixed temporal pattern. All subjects performed the task twenty-four times at both 20 and 40 dB SL, with and without 40 dB SL of contralateral noise for a total of 96 judgments. The results indicated that contralateral broad-band noise significantly improved the subjects' proficiency, as a group, to detect small changes in frequency, although intersubject differences were noted. The presentation level of the reference and variable signals was shown to have little or no effect on scores.