Time dependence of pitch perception-pitch step experiment

Abstract

In the pitch step experiment subjects tune an oscillator in three successive adjustments to match the pitch of a 15-msec sine-wave tone of frequency f2 that is immediately preceded by a 4-sec sine-wave tone with frequency f1 (900 <f1 < 1000 Hz) of the same intensity (82 dB). We find that for upward steps (f2 >f1) the matched tone frequency p2 tends to be greater than f2. This effect, whereby the pitch of tone 1 repels the pitch of tone 2 increases for decreasing |f2−f1|. The effect is reminiscent of the repulsion of a tone by a narrow noise band. [J. C. Webster and D. R. Muerdter, J. Acoust. Soc. Am. 37, 382–383 (1965)]. Therefore, a plot of p2−f1 versus f2−f1 is nonlinear (and possibly discontinuous) near the origin. If p2 is regarded as a description of the state of a pitch perceptor 15 msec after the step then the nonlinearity guarantees that no linear differential equation can describe the time-dependent response of the pitch perceptor. Dichotic experiments with tones 1 and 2 in different ears suggest that a repulsive-type nonlinearity is still present, though reduced in size. For downward pitch steps two of our subjects exhibit a repulsive effect (p2 <f2) and two subjects produce anomalously high p2 tunings.