After analyzing the vocabulary of more than 17,000 European children under the age of three, researchers identified a link between genetic factors that influence vocabulary size, literacy and cognition, and symptoms of cognitive deficit disorder. attention with or without hyperactivity (ADHD).
The number of words that children produce (expressive vocabulary) and understand (receptive vocabulary) changes rapidly during early development, in part due to genetic factors. “ Some variations in language development may be linked to variations in the genetic code stored in our cells “, explained Beate St Pourcain, co-author of a new study published in Biological Psychiatry.
The language learning difficulties they may face are linked to neurodevelopmental disorders such as ADHD and speech disorder. spectrumspectrum autistic. “ Are genetic factors underlying children’s language development linked to literacy and skills outcomes? cognitioncognition general later in life? » asked the researchers.
Assessing vocabulary size during the first years of life
Analysis at the scale of genomegenome on the vocabulary of more than 17,000 children of different languages (English, Dutch and Danish) reveals how genetics influences the production and comprehension of words from infancy to adulthood. Analyzes were carried out for expressive vocabulary in the early phase (infants aged 15 to 18 months), and expressive and receptive vocabulary in the late phase (toddlers aged 2 to 3 years). The researchers found that these genetic associations evolved dynamically during the first three years of life. Additionally, producing more words in the early phase and understanding fewer words in the late phase were associated with a higher risk of ADHD.
Ellen Verhoef, first author of the study, concludes: “ This study shows the importance of vocabulary size, assessed during the first years of life, for future behavior and cognition, and highlights the need for increased data collection efforts during early childhood and childhood. »
