The perception of pitch

• Published in: American scientist Vol. 62; no. 2; pp. 208 - 215
• Main Authors: Wightman, F L, Green, D M
• Format: Journal Article
• Language: English
• Published: United States 01-03-1974
• Subjects: Acoustic Stimulation; Humans; Pitch Discrimination; Sound
• ISSN: 0003-0996

More than a century of systematic study has not produced a satisfactory explanation of how the auditory system operates to determine the pitch of an acoustic stimulus. The fundamental problem is the invariance of the pitch percept; many sounds with quite different physical features are judged to have the same pitch (e.g., when different musical instruments play the same note). Early research suggested that pitch was related to the fundamental frequency of the sound wave, or its periodicity. In cases in which the fundamental was absent from the acoustic stimulus, (e.g., in certain musical instrument tones) it was presumed to be introduced by non-linear distortion in the ear. This hypothesis has been conclusively disproven by recent work. An alternative theory is that pitch is extracted by some sort of neural operation on the internal representation of the temporal fine-structure of the sound wave. Specifically, it has been suggested that pitch is given by the inverse of the time between the peaks (maximum pressure points) in the waveform. Such a theory can account for many phenomena that could not be encompassed by earlier theories. However, the fine-structure theories predict that changes in waveform fine-structure will be accompanied by changes in pitch, and this does not always occur. The evidence now available suggests that as far as pitch is concerned, the fine-structure of a sound wave does not matter; all stimuli with the same spectral components have the same pitch. At this point it is clear that: (1) The operations by which the auditory system extracts pitch from an acoustic stimulus are anything but simple; and (2) Those operations are still unknown. Pitch perception is still very much a mystery. AA