Critical periods in speech perception: new directions

Area of Science:

• Developmental Neuroscience
• Linguistics
• Cognitive Science

Background:

• The existence and nature of critical periods (CPs) for language acquisition remain a key debate.
• Neurobiological advances offer mechanistic explanations for CPs, involving excitatory/inhibitory balance and molecular brakes.
• Understanding these mechanisms is crucial for explaining developmental plasticity in language learning.

Purpose of the Study:

• To review human speech perception development literature through the lens of a neurobiological critical period model.
• To highlight research on maturational and experiential influences on plasticity during development.
• To reframe the debate on critical periods from 'if they exist' to 'how they function'.

Main Methods:

• Literature review of human speech perception development.
• Integration of neurobiological findings on plasticity mechanisms.
• Analysis of studies examining critical period models in human subjects.

Main Results:

• Evidence suggests interplay between maturational and experiential factors in shaping speech perception development.
• Neurobiological mechanisms provide a framework for understanding the onset and offset of developmental plasticity.
• Paradigmatic examples illustrate the application of critical period models to human development.

Conclusions:

• A mechanistic understanding shifts the focus from the existence of critical periods to the processes governing them.
• Future research should investigate the specific mechanisms that open, maintain, close, and reopen windows of plasticity.
• This perspective refines the study of language acquisition and developmental neuroscience.