Changes in the perception of synthetic nasal consonants as a result of vowel formant manipulations
There is controversy over the role of auditory scene analysis in speech perception and in particular whether listeners form perceptual streams of formants. The role of vowel formant frequencies in the perception of synthetic vowelnasal syllables and the importance of formant continuity between vowel and nasal were examined in three experiments. The nasal prototypes /m/ and /n/ were used in all experiments, together with a range of preceding vowels differing only in the frequency and transitions of their second formant (F2). When no explicit transitions were present between the vowel and nasal, the perception of each nasal changed from /m/ to /n/ as the vowel F2 increased. Introducing explicit formant transitions removed this effect, and listeners heard the appropriate percepts for each nasal prototype. However, if the transition and the nasal prototype were inconsistent, the percept was determined by the transition alone. In each experiment, therefore, the target frequency of the vowel F2 transition into the nasal consonant determined the percept, taking precedence over the formant structure of the nasal prototype. The results do not show strong evidence for formant streaming and are more consistent with pattern matching processes.
nasal consonants auditory scene analysis formant continuity proximity grouping