Screen Time Patterns and Cognitive Development Among Preschool Children

INTRODUCTION: Major gaps limit the comprehensive understanding of the associations between screen time and cognitive development in preschool years. The objectives of this study were to examine (1) screen time patterns and (2) the associations between screen time patterns and cognitive development in preschool children. METHODS: This cross-sectional study used baseline data, collected between October 2022 and December 2023 and analyzed in 2025, from the TECHnology and Development in Early Childhood project. Participants were 359 preschool children (aged 3, 3.5, or 4 years ± 2 weeks) and their parents from Western Canada. Screen time patterns (type: show/movie/video, electronic game, communication; content: parent-defined educational or entertainment, researcher-defined educational or entertainment; device: TV, mobile [tablet/smartphone]; context: co-use with an adult, evening) were parent reported using a 2-week online daily diary. Cognitive development (language, response inhibition, working memory, self-control) was assessed through 4 established short games administered by researchers during a recorded virtual meeting. Regression models adjusted for covariates were conducted. RESULTS: Based on 4,774 days of data, children had an average of 77 min/day of screen time. The most prevalent type and content of screen time across devices were show/movie/video (69 min/day) and entertainment (parent defined; 55 min/day) screen time, respectively. Higher levels of show/movie/video, mobile device, and parent-defined entertainment screen time (10 min/day) were consistently associated with less advanced executive function scores (response inhibition: B= -0.45 to -0.62; working memory: B= -0.02 to -0.03; self-control: B= -0.86, -1.05). For language, engaging in versus not engaging in communication screen time (B=1.71; p=0.037) and co-use with an adult (B=1.88; p=0.039) was associated with more advanced scores, only when nontypical and typical days were included. CONCLUSIONS: Entertainment shows/movies/videos were common among preschool children. Some patterns of screen time appeared to be more detrimental to cognitive development than others. Findings can help inform more nuanced screen time recommendations and interventions that aim to minimize harm and maximize the benefits of this societal reality.