Narrowing perceptual sensitivity to the native language in infancy: exogenous influences on developmental timing.

Mayada Elsabbagh,Annette Hohenberger,Josette Serres,Scania De Schonen,Ruth Campos,Annette Karmiloff-Smith,Jo Van Herwegen,Gisa Aschersleben

doi:10.3390/bs3010120

Abstract

The infancy literature situates the perceptual narrowing of speech sounds at around 10 months of age, but little is known about the mechanisms that influence individual differences in this developmental milestone. We hypothesized that such differences might in part be explained by characteristics of mother-child interaction. Infant sensitivity to syllables from their native tongue was compared longitudinally to sensitivity to non-native phonemes, at 6 months and again at 10 months. We replicated previous findings that at the group level, both 6- and 10- month-olds were able to discriminate contrasts in their native language, but only 6-month-olds succeeded in discriminating contrasts in the non-native language. However, when discrimination was assessed for separate groups on the basis of mother-child interaction—a ‘high contingency group’ and a ‘moderate contingency’ group—the vast majority of infants in both groups showed the expected developmental pattern by 10 months, but only infants in the ‘high contingency’ group showed early specialization for their native phonemes by failing to discriminate non-native contrasts at 6-months. The findings suggest that the quality of mother-child interaction is one of the exogenous factors influencing the timing of infant specialization for speech processing.

Highlights

Within the first few years of life, infants acquire their native language with remarkable ease
To test the relationship between contingency in the context of naturalistic mother-child interactions and speech discrimination, we focus on a well-replicated milestone where infants narrow their perceptual sensitivity to native language contrasts
The results indicated that total looking time in the familiarization phase was remarkably similar

Summary

Introduction

Within the first few years of life, infants acquire their native language with remarkable ease. Debate continues as to whether some components of speech and language are genetically determined [3,4], but there is little controversy about the fact that infants show remarkable readiness and sensitivity to acquiring language and that experience contributes to shaping these abilities over development. Over the first year of life, infants’ perceptual capacities become progressively more specialized in a fashion consistent with the rhythmic and prosodic patterns of their mother tongue [5,6,7]. At 6 months, infants are able to discriminate speech sounds from a variety of different language families. By 10–12 months of age, their perceptual abilities are narrowed to those sounds relevant to their own language [8,9,10]. The nature of the decline in perceptual sensitivity is tightly bound to the characteristics of the language being acquired, implying that the perceptual system does not turn on or off a particular speech contrast, but rather that the system undergoes substantial dynamic reorganization during this early period [8,11]

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