Effects of feedback filtering on nasalization and self-perception of nasality

The effects of feedback filtering on nasality perception were investigated by having speakers produce sentences while hearing their voices unfiltered and low-pass filtered with cut-off frequencies of 1000, 500, and 300 Hz. As they spoke, speakers judged the nasality in their productions using a ratio scale. Measurements of nasalization were made with a miniature accelerometer attached to the side of the speaker's nose. Data obtained indicate that the speakers decreased their nasalization slightly when they heard their voices low-pass filtered at each cut-off frequency. However, they did not perceive consistent changes in their own nasality during the filtered conditions. These findings are interpreted as suggesting that nasalization is influenced by filtering air-conducted auditory information and that relationships between the acoustic correlates of nasalization and self-perception of nasality are complex.