Acoustic and perceptual evidence of a complex relation between F1 and F0 in determining vowel height

An acoustic analysis of five vowels of American English [I, e, ae, α, Λ], spoken by three speakers, showed that in the dimension representing vowel height, individual differences for low vowels were reduced when the vowels are represented by the (F1 - F10) difference rather than by F1. However, individual differences for high vowels were increased by the use of the same distance. Results of perceptual experiments using synthetic CVC and one-formant stimuli were in agreement with the observations based on the acoustic analysis. They suggest that the relation between F1 and F0 depends on the ranges of both F0 and F1 values. A possible interpretation consists in giving to F0 the role of an anchor point when both F0 and F1 are sufficiently high, while the extreme end of the scale would serve as the reference point when F0 or F1 assume values in the low frequency range.