Language and socio-emotional development of children before, during, and after COVID-19: Lessons from the YOUth...

COVID-19 regulations limited young children's social learning experiences. This large-scale study examined whether children (5 months-4 years) assessed during or after the COVID-19 pandemic differ in language and socio-emotional development. We compared data from 2,166 children tested pre- (July 2015-March 2020), during (March 2020-July 2022), and post-COVID-19 regulations (July 2022-October 2023). Vocabulary was measured using the Dutch MacArthur-Bates Communicative Development Inventories as used in the YOUth cohorts at 10 months and Dutch MacArthur-Bates Communicative Development Inventories as used in the YOUth cohorts and the Dutch version of the third edition of the Peabody Picture Vocabulary Test at 2-4 years. Socio-emotional development was assessed using Ages and Stages Questionnaires: Social-Emotional at 5 months, 10 months, and 2-4 years. Compared to prepandemic children, 2-year olds and 3-year olds had smaller vocabularies after the pandemic. For socio-emotional development, problems increased in infants and male preschoolers both during and after the pandemic. For preschoolers, screen time rose sharply during the pandemic and was negatively linked to receptive vocabulary. While shared reading supported vocabulary development, there is no evidence that shared reading increased during the pandemic. Overall, the findings indicate that COVID-19 regulations had both immediate and continuing effects on children's language and socio-emotional development. (PsycInfo Database Record (c) 2026 APA, all rights reserved).