Perceptual attunement in vowels: a meta-analysis

Area of Science:

• Developmental Psychology
• Linguistics
• Cognitive Neuroscience

Background:

• Infant speech perception models often generalize consonant findings to vowels.
• Vowel perception is assumed to improve for native sounds and decline for non-native sounds within the first year of life.
• Limited quantitative data exists on perceptual narrowing for infant vowels.

Purpose of the Study:

• To conduct the first comprehensive quantitative meta-analysis of perceptual narrowing in infant vowel discrimination.
• To assess the accuracy of current models of infant speech perception regarding vowels.
• To examine age-related changes in native and non-native vowel discrimination in infants.

Main Methods:

• Meta-analysis of studies on infant vowel discrimination (0-14 months).
• Inclusion of behavioral, electrophysiological, and neuroimaging methods.
• Analysis of effect sizes for native and non-native vowel discrimination over the first year of life.

Main Results:

• Effect sizes for native and non-native vowel discrimination changed in opposite directions with age.
• Significant changes in vowel discrimination were observed by approximately 6 months of age.
• Findings challenge the generalized assumption of perceptual narrowing for vowels.

Conclusions:

• Infant vowel perception undergoes significant changes within the first year, but not as previously modeled.
• Vowel discrimination abilities diverge for native and non-native sounds earlier than expected.
• Further research is needed to refine models of infant speech perception for vowels.