Infant sensitivity to distributional information can affect phonetic discrimination

Area of Science:

• Developmental Psychology
• Linguistics
• Auditory Perception

Background:

• Infants' speech sound perception is shaped by native language input within the first year of life.
• The precise mechanism driving these developmental changes in speech perception has been unclear.

Purpose of the Study:

• To provide the first evidence for a mechanism explaining how infants' native language input affects speech sound perception.
• To investigate the role of statistical distribution of phonetic variation in infant speech perception.

Main Methods:

• Familiarizing 6- and 8-month-old infants with speech sounds from a phonetic continuum.
• Presenting speech sounds with either a bimodal or unimodal frequency distribution during familiarization.
• Testing infants' ability to discriminate speech sounds from the continuum endpoints.

Main Results:

• Infants exposed to a bimodal distribution of speech sounds discriminated endpoint tokens.
• Infants exposed to a unimodal distribution did not discriminate endpoint tokens.
• Sensitivity to statistical distribution of speech sounds influences speech perception.

Conclusions:

• Infants are sensitive to the statistical distribution of phonetic variation in their linguistic environment.
• This sensitivity is a key mechanism influencing the developmental changes in infant speech perception.
• Findings shed light on early language acquisition and the plasticity of auditory processing.