Preschool language ability is predicted by toddler hand preference trajectories

Area of Science:

• Developmental Psychology
• Neuroscience
• Linguistics

Background:

• Previous research links toddler handedness consistency in role-differentiated bimanual manipulation (RDBM) to language development.
• Understanding the long-term impact of early fine motor skill hand preference on language is crucial.

Purpose of the Study:

• To investigate if RDBM hand preference consistency from 18-24 months predicts language abilities at 5 years.
• To identify distinct hand preference trajectories in toddlers.

Main Methods:

• Latent class growth analysis was used to identify RDBM hand preference trajectories in 90 toddlers.
• Language abilities were assessed at age 5 using the Preschool Language Scales 5th edition (PLS-5).

Main Results:

• Three RDBM hand preference trajectories were identified: left-moderate right, right-moderate left, and right-mild left.
• Children with a right-mild left trajectory showed significantly higher receptive and expressive language scores at age 5 compared to the left-moderate right group.
• The right-mild left group also outperformed the right-moderate left group in receptive language.

Conclusions:

• Individual differences in toddler hand preference consistency for RDBM have lasting effects on language development.
• Specific patterns of early hand preference, particularly consistent right-hand use, are associated with better language outcomes in preschool years.