Effect of auditory fatigue on frequency discrimination

Abstract

An attempt was made to demonstrate changes in frequency discrimination following a 3-min exposure to a pure tone. Thirty subjects adjusted a variable tone to be just higher or just lower in pitch than a standard frequency. These judgments were made prior to and following exposure to either a 250-Hz or a 4-kHz tone. Three separate standard frequencies were used with each of the exposure tones. When 250 Hz was the fatiguing frequency, pitch judgments were made using 180, 250, and 350 Hz as standards. For the 4-kHz exposure, the standard frequencies were 2.8, 4, and 5.6 kHz. In addition to pitch judgments, the experimental design produced estimates of threshold sensitivity for the test tone. A complete control run was made for each exposure-standard frequency combination. As was the case with previous research in this area, this experimental procedure was unable to show any appreciable effect on frequency discrimination following pure tone exposure. The experiment did produce an interesting secondary observation. There was a distinct asymmetry in the pitch judgments above and below the standard frequency. The asymmetry was particularly noticeable when the standard frequency was 5.6 kHz.