Frequency discrimination following linear frequency glide

Abstract

Difference limen for frequency (DLF) following linear frequency glide was measured using 2IFC procedure to investigate mechanisms underlying detection of frequency change in successive tones. In the experiment, a pair of 100-ms tone, one of which had fixed frequency of 1000 Hz, was presented. The interval between the two pulses was 200 ms and the order of pulses in each trial was randomized. An adapting tone preceded each pair by 200 ms and was either 200-ms linear frequency glide with frequency extent of 100 Hz (950–1050 Hz) or 200-ms stationary tone of 1000 Hz. In the result, when the glide preceded the pair of pulses, DLFs at 1000 Hz were significantly elevated irrespective of direction of glide compared to DLFs with no preceding tones. The stationary sine wave, however, had no effect on DLFs as several previous studies have reported. In sum, unidirectional continuous change of frequency disrupted a process of sampling and comparing frequencies from successive tones. These results indicate that the process of detecting continuous and successive change of frequency are at least partially mediated by a common mechanism.