Developmental speech perception

Previous research has indicated that infants have the ability to categorically discriminate many of the distinctive features of speech sounds regardless of their exposure to a language in which such distinctions are important, whereas adults of one language group may have difficulty discriminating linguistic features that are important in a foreign language. This suggests a decline during development in linguistic perceptual abilities, during which the ability to discriminate non-relevant features may be lost. This study was designed to be the first in a series of tests of such a decline and involved comparing English-speaking adults, Hindi speaking adults, and six-month old infants on their ability to discriminate foreign and native speech contrasts. Two pairs of Hindi sounds, and one pair of English sounds were investigated in this study, Infants were tested in a "visually reinforced infant speech discrimination" (VRISD) paradigm. This is a discrimination paradigm in which the infant is conditioned to turn its head when there is a change in the auditory stimulus. A variate of this paradigm was employed for the adult subjects using a button-press, rather than a head turn, as the critical behavioral response. This study yielded support for the notion that infants have the ability to categorically discriminate distinctive features of speech sounds regardless of exposure to a language in which such distinctions are important. Some support was also given for the idea that there may be a decline in speech perceptual abilities with either age/or linguistic experience, but this finding was only significant with one of the two Hindi sound pairs. Two explanations are offered for these results. It is suggested that the English population may have had someexperience with the non-significant Hindi contrast. Alternatively, it is suggested that differential perceptual distance may have accounted for the differences between the two Hindi sound pairs. Two levels of processing, acoustic and linguistic, are then invoked in this explanation.Arts, Faculty ofPsychology, Department ofGraduat