Reference frame and scaling in the perception of pitch in a tone language

Abstract

Listeners can make subtle judgments about the relative magnitudes of auditory objects but only rarely make judgments of the absolute size of speech stimuli. In a pioneering paper, and his first publication in 1957, Peter Ladefoged demonstrated that the relative size of the surrounding context affects the perception of vowel quality. Although, years later, Ladefoged showed that the effect is only valid under certain conditions, the effect is still a motivated perceptual phenomenon. In this paper, the role of the reference frame in the perception of pitch in Yalalag Zapotec is investigated. YZ has three phonemic tones, high, low, and falling. Minimal pairs of H and L tones were introduced by a carrier sentence. The experiment manipulated the F0 of the Zapotec equivalent sentence to ‘‘Please say what this word is,’’ while the target words were kept unmodified. Other things being equal, the only difference was the F0 of six versions of the introductory sentence. Preliminary results are analogous to Ladefoged’s original findings on the identification of vowels: listeners’ pitch judgments are influenced by the overall auditory context in which they occur. The results suggest that perception of pitch for listeners of tone languages depends on allocentric frames of reference.