Children who spent their early toddler years under pandemic conditions are entering preschool with smaller vocabularies and higher rates of social-emotional difficulty than children born just a few years earlier. These developmental gaps persisted even after social restrictions completely ended.
Toddlers who lived through pandemic disruptions show measurable vocabulary delays and heightened behavioral struggles compared to pre-2020 cohorts, driven in part by sustained increases in daily screen time.
Early speech delays and emotional dysregulation directly undermine kindergarten readiness and early learning momentum. If your 2- to 4-year-old seems behind on vocabulary or extra quick to melt down, it likely reflects a cohort-wide loss of early social exposure rather than an isolated developmental issue. Knowing that screen habits and lost peer play created this gap gives parents a clear, actionable target for home routines.
Early childhood disruptions during the pandemic raised urgent questions about whether developmental delays were temporary glitches or lasting shifts. Researchers tracked 2,166 Dutch children over eight years to isolate how disrupted daycare, reduced peer play, and soaring screen time impacted long-term growth before, during, and after COVID-19 regulations.
The developmental hangover of the pandemic extends past the lockdown period itself.
- Vocabularies shrank: Two- and three-year-olds evaluated after pandemic restrictions ended scored significantly lower on receptive vocabulary tests than same-aged children tested before 2020.
- Behavioral problems rose: Social-emotional challenges increased among infants and male preschoolers both during and after the regulation period.
- Screen time stayed high: Preschoolers' screen hours jumped during the pandemic and correlated directly with lower vocabulary scores.
- Reading protected language: Shared book reading consistently safeguarded vocabulary development, though parents did not increase reading time during the pandemic to compensate for lost activities.
Pandemic screen habits hardened into permanent routines that continue to crowd out verbal interaction long after lockdowns ended. High screen use during shutdowns was treated as a temporary sanity saver, but families never fully reclaimed those lost hours for conversational play. Furthermore, young boys appear particularly vulnerable to the loss of structured out-of-home play, manifesting in lingering behavioral dysregulation.
Observational data across a single national cohort cannot definitively prove that pandemic regulations were the sole cause of these developmental shifts. The study relied on parent-reported questionnaires, which means elevated parental stress could have influenced how caregivers rated their children's language and behavior. Additionally, results from the Netherlands may not fully translate to countries with vastly different lockdown durations or school closures.
- If your child is between two and four and slow to pick up new words: Prioritize 15 minutes of interactive daily picture book reading to directly boost receptive vocabulary.
- If daily screen time has remained high since the pandemic: Replace passive viewing with conversational audiobooks or unstructured physical play to reopen time for verbal back-and-forth.
- If your young boy struggles with frequent meltdowns or emotional outbursts: Increase structured peer play and physical activity to actively rebuild lost social-emotional environments.
Widespread speech and behavioral delays in today's preschoolers reflect a broad environmental shift rather than an individual child's deficit. Bridging these gaps does not require expensive interventions for most children—replacing passive screen time with daily interactive reading provides the exact conversational stimulus this cohort missed.
van der Klis A, Junge C (2026). Language and socio-emotional development of children before, during, and after COVID-19: Lessons from the YOUth cohort. Developmental psychology. doi:10.1037/dev0002215 — pubmed.ncbi.nlm.nih.gov