Associations Between Early Screen Exposure and Neurocognitive Outcomes in Children Aged 2-5 Years: A Systematic Review.

Background/Objectives: Screen exposure is widespread in preschool children, but developmental associations are difficult to interpret because use varies by duration, content, and caregiving context. This review synthesized evidence on associations with language development, general cognitive performance, attention regulation, and executive functioning in typically developing children aged 2-5 years. Methods: PubMed, Web of Science, and Scopus were searched for peer-reviewed English-language quantitative studies published between January 2000 and December 2025. Study selection followed PRISMA 2020. Risk of bias was assessed using design-specific JBI critical appraisal tools. Of 1105 records identified, 860 remained after duplicate removal; 115 full texts were assessed, and 43 studies were included. Findings were narratively synthesized because of heterogeneity in exposure definitions, outcome measures, study designs, and effect estimates. Results: Greater screen exposure was generally associated with less favourable language outcomes, particularly expressive language, vocabulary, communication, and developmental measures. Attention regulation, self-regulation, and selected executive-function outcomes also showed adverse associations; findings for inhibitory control, working memory, cognitive flexibility, and general cognitive performance were more heterogeneous. Passive viewing, background media, solitary use, and highly stimulating entertainment-oriented content were more often associated with less favourable outcomes. Caregiver co-viewing, joint media engagement, and developmentally appropriate content were associated with weaker adverse or neutral findings. Most studies relied on parent-reported exposure and observational designs. Given the predominance of observational evidence, these associations should not be interpreted as causal, and residual confounding and reverse causality remain possible. Conclusions: Screen exposure in children aged 2-5 years is associated with neurocognitive outcomes in a context-dependent manner. Duration alone is insufficient; content, background exposure, caregiver involvement, family routines, and the home learning environment should also be considered. Findings support cautious, family-centred guidance and stronger longitudinal and intervention studies with more precise exposure measurement.