Our Research Lab
Categorical Speech Perception
In an effort to better understand the elemental nature of speech perception in background noise, we have undertaken a study of the categorical perception of speech stimuli in the presence of speech babble. One of our long-term goals is to use such a method in the fitting, tuning, and evaluation of hearing enhancement technologies such as hearing aids. To get started, we evaluated the influence of background noise on categorical perception by considering five categorical continua and four different listening conditions (speech in quiet and speech in babble with three speech-to-babble ratios). The data clearly indicate that noise impacts categorical perception in multiple ways. For some continua, such as /ba/ to /da/, the effect of noise is to make the categorical function more shallow and to shift it slightly towards the /da/ end of the continuum. For others, such as the /a/ to /a/ continuum, noise has very little impact on perception over the range of speech-to-babble ratios evaluated in this study. See also Hearing Enhancement Technologies below.
Categorical perception for synthetic speech that vary along five different continua. Data are the average of 25 young adult listeners with normal hearing sensitivity as indexed by pure-tone audiometric thresholds.