Auditory short-term memory and vowel perception.

The distinction between categorical and continuous modes of speech perception has played an important role in recent theoretical accounts of the speech perception process. Certain classes of speech sounds such as stop consonants are usually perceived in a categorical or phonetic mode. Listeners can discriminate between two sounds only to the extent that they have identified those stimuli as different phonetic segments. Recently, several findings have suggested that vowels, which are usually perceived in a continuous mode, may also be perceived in a categorical-like mode, although this outcome may be dependent upon various experimental manipulations. This paper reports three experiments that examined the role of auditory short-term memory in the discrimination of brief 50-msec vowels and longer 300-msec vowels. Although vowels may be perceived in a categorical-like mode, differences still exist in perception between stop consonants and steady state vowels. The findings are discussed in relation to auditory and phonetic coding in short-term memory.