Effects of energetic masking and informational masking on the perception of Cantonese tones in monosyllabic words

Abstract

This study aimed to examine the effects of energetic masking and informational masking on Cantonese tone perception, the differential pattern that noise affects perception of the six Cantonese lexical tones, and the factors determining the effectiveness of masking on pitch perception. Four types of noise, including ten-talker babble, two-male-talker babble, two-female-talker babble, and speech-shaped noise, were used to represent conditions involving various amounts of energetic masking and informational masking. Two signal-to-noise ratios were employed for each type of noise. A quiet condition served as control. Twenty university students (8 male and 12 female) participated in the study. Each participant listened to and repeated Cantonese monosyllabic words in quiet and noise conditions respectively and the experimenter recorded the tones. The result showed that (1) Cantonese tone perception was largely prone to the combined effect of energetic masking and informational masking and it was more adversely affected by energetic masking than informational masking; (2) the effect of noise was more significant on contour tones than level tones, suggesting that, in noisy environment, noise exerted a larger effect on perception of pitch change than that of pitch level; (3) the masking effect of babble noise on pitch perception increased with the number of masker talkers.