Linguistic and non-linguistic non-adjacent dependency learning in early development

Area of Science:

• Developmental neuroscience
• Psycholinguistics
• Cognitive development

Background:

• Non-adjacent dependencies (NADs) are crucial for language acquisition.
• Previous studies show developmental changes in neural signatures of NAD learning.
• The specific brain regions and non-linguistic parallels of this shift are unclear.

Purpose of the Study:

• To identify brain regions involved in the developmental shift of linguistic NAD learning.
• To investigate if this developmental shift extends to non-linguistic NAD learning.
• To compare neural mechanisms of linguistic versus non-linguistic NAD learning across development.

Main Methods:

• Functional near-infrared spectroscopy (fNIRS) recorded hemodynamic responses in children.
• Two experiments exposed 2- and 3-year-old children to linguistic (Italian sentences) and non-linguistic (tone sequences) NADs.
• Children were tested on their detection of NAD violations.

Main Results:

• 2-year-olds showed NAD detection in left temporal, inferior frontal, and parietal regions for linguistic NADs.
• 3-year-olds did not show the same linguistic NAD detection pattern.
• 3-year-olds, but not 2-year-olds, detected non-linguistic NAD violations.

Conclusions:

• A developmental shift in the neural basis of linguistic NAD learning occurs between ages 2 and 3.
• Distinct neural mechanisms underlie linguistic and non-linguistic NAD learning.
• This study highlights age-related changes in how children learn complex dependencies.