Traunmüller (1981) suggested that the tonotopic distance between the first formant (F1) and the fundamental frequency (F0) is a major determinant of perceived vowel height. In the present study, subjects identified a vowel-height continuum ranging in formant pattern from /I/to/epsilon/, at five F0 values. Increasing F0 led to an increased probability of /I/responses (i.e., the phoneme boundary shifted toward the /epsilon/ end of the continuum). Various conditions of filtering out the lower harmonics of the stimuli caused only marginal shifts of the phoneme boundary. The experiments provide evidence against interpretations of Traunmüller's (1981) results that claim that vowel height is determined by the distance between F1 and the lowest harmonic that is present in the basilar membrane excitation pattern.