Kelley L. Kaye
Univ. of Texas at Dallas, Box 830688 GR 4.1, Richardson, TX 75083-0688
There is some controversy concerning what constitutes the perceptual unit of speech. Bertoncini and Mehler [Infant Behav. Dev. 4, 247--260 (1981)] have presented evidence from infants supporting the syllable over the phoneme. The present study investigated this issue with newborns. Twenty-four subjects were presented with lists of nonsense syllables (CVC's) over earphones, using an operant choice preference sucking procedure. The lists varied in number of syllables (length) and also in number of phonemes (complexity). Two contradictory effects occurred: the number of sucks produced decreased as syllables were added, and the number of sucks increased as phonemes were added. Speech perception in newborns thus requires two processes: the multidimensional space of the utterances is defined in terms of distinctive features, requiring a large number of presentations. Subsequently, the infant operates on the units defined in that space, with processing largely occurring in memory whereby the increased memory load suppresses sucking. An experiment to test this interpretation has been carried out, and will also be discussed.