A Study on the Perception of Fundamental Frequency Declination by Japanese Speakers.

Abstract

The present series of experiments increase our understanding on the perception of Fo contours. We have presented data here that speakers of Japanese normalize for declination in judging pitch height of synthetic stimuli and they judge that the final syllable is equal to the initial one in pitch even if Fo of the former is 4 to 8 Hz lower than that of the latter. This effect is more clearly demonstrated in concave type contours than in convex type contours. In connection with this, it can be argued that Fo of the syllable preceding the final one affects the normalization effect, and if the Fo is higher than that of the final one, the effect is weakened. Subjects tend to normalize for declination of Fo contours in a categorical manner in concave type and this implies that normalization works within a limited range of Fo difference between two peaks. Furthermore, normalization is proportional, though not consistent, to the length of stimuli, especially in concave type. Based on the response data for equal judgement, the effect was greater in seven-syllable set than in three-and five-syllable sets, but there was no noticeable difference between three- and five-syllable sets. Normalization in the perception of Fo contours can be accounted for by perceptual compensation for declination of pitch contours in production. The effect works in the direction to correct declination of Fo contours in production, and this direction is more perceptually significant than the absolute frequencies in exerting the effect.