The function of F0-based pitch

Abstract

Pitch is traditionally described as the perceptual correlate of a sound’s fundamental frequency (F0). The importance of perceiving F0 is often attributed to the need to compare sounds with different timbres, for which spectral comparisons might be error-prone. Alternatively, because the F0 is a summary measure of a set of harmonic frequencies, it could provide a compressed representation of sound for memory storage. To clarify the function of F0-based pitch, we tested its importance for discriminating sounds with different spectra, and sounds separated by delays, using both harmonic and inharmonic stimuli. If a task relies on F0-based pitch, performance should be impaired for inharmonic stimuli. We observed an advantage for harmonic stimuli for discrimination of synthetic tones with extreme (and unnatural) spectral variation. However, no such advantage was observed for instrument or speech fragments (with naturally occurring spectral variation). By contrast, discrimination was better for harmonic tones separated by brief (5–10 s) delays, suggesting that F0-based pitch aided storage across the delay. The results indicate that the spectral variation found in natural pitched sounds does not itself make listeners reliant on F0 estimation. The results raise the possibility that F0 primarily serves to facilitate compression of sounds for memory storage.