Bosch, L. 1, 2 , Solé, J. . 1 , Iriondo, M. 3 , Agut, T. 3 & Botet, F. 4
1 Basic Psychology Department, University of Barcelona
2 Institut for Brain, Cognition and Behavior (IR3C), University of Barcelona
3 Neonatology Unit, Hospital Sant Joan de Déu (Barcelona)
4 Neonatology Unit, Maternitat-Hospital Clínic (Barcelona)
Perceptual reorganization processes relative to changes in phonetic discrimination abilities take place in the first year of life. These changes are the result of language experience. Fine-tuning to the sound categories of the native language usually involves a decrease in sensitivity for phonetic contrasts that are not present in the ambient language. The present research is aimed at further exploring the contribution of language exposure and brain maturation onto infants? sensitivity changes for native and non-native vowels. By comparing two different populations (full terms and ?healthy? pre-terms) at 4 and 8 months of age (corrected for gestation in the preterm group), the early effect of linguistic experience on the developing brain can be assessed. A similar behavior in both groups can be predicted if, in spite of differences in listening experience, maturation is critical for these perceptual changes to appear. However, if language exposure is the critical factor, a decline in non-native vowel discrimination might already be observed in the pre-term population at the younger age tested (4 months, corrected for gestation).
Two groups of pre-terms (?32 gestation weeks; ?1.500g birth weight, with no congenital, physical or severe neurological anomalies) and two groups of full term infants were followed longitudinally and tested on the native /do/-/du/ and the non-native /do/-/dò/ contrasts, respectively. At the younger age, results showed a similar discrimination pattern in both groups for the native contrast, but critically, not for the non-native contrast: discrimination could only be gathered in the full term group. When tested at 8 months of age, full terms showed the expected decrease in sensitivity for the non-native contrast and pre-terms replicated their previous results at the younger age. Taken together, data suggest that language experience is determinant for the perceptual reorganization processes to take place, even in the presence of maturational constraints.