Infants' discrimination of full and partial cues to place of articulation in stop consonants

Abstract

Stevens and Blumstein [J. Acoust. Soc. Am. 64, 1358–1368 (1978)] have proposed that the shape of the onset spectrum provides contextually invariant information about place of stop consonant articulation for CV syllables and that these primary spectral attributes underlie the. infant's ability to discriminate place differences. According to this view, contextually variable formant transitions constitute only secondary or “learned” cues to place of articulation. Prelinguistic infants are, therefore, assumed to be incapable of discriminating place differences in two-formant stimuli which supposedly lack invariant spectral attributes. Our analysis revealed, however, that the two-formant labial and velar CV stimuli are spectrally very similar to their full-formant counterparts. Therefore, if spectral shape does cue place of articulation, infants should actually discriminate these stimuli. An operant head-turning paradigm was employed to test this hypothesis with 6–9 month old infants. The results indicated that infants can discriminate two-formant stimuli—a finding which renders the distinction between primary versus secondary cues invalid. Moreover, because several infants discriminated the two-formant alveolar and velar stimuli, whose onset spectra are very similar, it is probably not the shape of the spectrum at stimulus onset which mediates infants' discrimination of place of articulation in stop consonants. [Work supported by NICHHD, NIMH, and Research Council of Canada.]