Impairment of Pitch Perception by Temporally Contiguous Stimuli

Abstract

Two experiments were run, combining elements of designs by Elliott (1970) and Massaro (1970), in which noise and pure-tone “masks” bore varying temporal relations to two stimulus tones. The tones, either 20-msec duration (“short”) or 400-msec (“long”) were initiated 4 sec apart; either the first or second was variable, the other fixed (1000 Hz). The mask, an 80-dB white noise or 2193-Hz tone 500 msec long was inserted (position 1) 40 msec after the first tone or (position 2) terminated 40 msec before the second tone, or (position 3) initiated 40 msec after the second tone. In the first experiment, the variable was 1000 or 1050 Hz (“coarse discrimination”); in the second, 1000 or 1025 Hz (“fine”). Discrimination was impaired, especially for short tones, though impairment was minimal in position 2. Impairment was greater by tone than noise in position 1 only and more so for the fine discrimination in position 3 only. One interpretation is that “masking” consists of two kinds of disruption, one associated with storage and one with pitch comparison.