中華心理學刊
民97，50卷，2期，111-124

Feng-Ming Tsao（Department of Psychology, National Taiwan University）

Abstract

Speech perception abilities undergo rapid changes around the first birthday, such as developing the language-specific phonetic perception and word segmentation, but only a few studies have examined the development of lexical-tones, an essential phonetic unit to distinguish the meanings of syllables in Mandarin Chinese. This study explored the native tone perception of one-year-old Mandarin-learning infants.
Specifically, this study addressed whether the acoustic similarity between lexical tones affected infants’perceptual discrimination performance. Infants (n = 109) were tested with the conditioned head-turn procedure when discriminating tone contrasts, Tone 1 vs. 3, 2 vs. 3, and 2 vs. 4, varying in the similarity of average fundamental frequency (F0) and F0 contour. Results showed that infants better discriminated tone contrast
with greater acoustical differences (Tone 1 vs. 3), but they were less accurate discriminating acoustically similar tone contrasts (Tone 2 vs. 3 and Tone 2 vs. 4). Directional asymmetry was evident with the Tone 1 vs. 3 contrast, as the change from the background Tone 1 syllable to the target Tone 3 syllable was easier than the reverse. The results suggest that auditory processing is the essential mechanism for one-year-old infants
to perceive native lexical tones, and that the perceptual mechanism for lexical tone in infants differs from Mandarin-speaking adults.

Keywords: native lexical-tone perception, infant speech perception, acoustical similarity of tone, directional asymmetry