Screens are now a routine part of life for many young children, raising growing questions about how early exposure could influence development over time. New longitudinal research that tracked children from age 1 through age 8 found that greater screen viewing, especially during infancy and around the time children begin school, was associated with lower academic performance at age 9 and weaker working memory at age 10.5. The results suggest that when children are exposed to screens could matter just as much as how much time they spend using them.
The World Health Organization (WHO) and the American Academy of Pediatrics recommend avoiding screen use before 18-24 months and limiting it to less than one hour per day for children ages 2 to 5. Many children, however, spend more time with screens than those guidelines advise. Research into the effects of screen viewing on cognitive development has also produced mixed results. Much of the previous work has relied on snapshots taken at a single point in time, focused mainly on school-age children, or lacked repeated measurements throughout early childhood. Studies that follow children across several developmental stages can help identify periods when screen exposure may be especially important while also accounting more effectively for family and environmental factors.
Tracking Screen Time From Infancy Through Childhood
Researchers from Inserm and the National University of Singapore conducted the study, which was published in the World Journal of Pediatrics. Using information from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort, the team examined parent-reported screen viewing at six different ages. They then compared those measurements with children’s academic performance and working memory several years later.
The analysis included 502 children who were followed from infancy into middle childhood. Higher screen viewing during certain stages of development was associated with poorer academic results later on and weaker working memory. The clearest patterns appeared for screen exposure during infancy and near the beginning of formal schooling, indicating that these periods may be particularly sensitive for cognitive development.
Children who accumulated more screen exposure across childhood also tended to perform less well academically. Together, the findings suggest that total viewing time is only part of the picture. The age at which heavier screen use occurs may also be important, with early childhood potentially representing a period when screen habits have longer-term implications for learning and memory.
Age 1 Showed the Strongest Association
“The effect sizes we saw at age 1 were the largest among all time points we examined,” the authors said. “That suggests early infancy may be a window of heightened sensitivity, when the developing brain is particularly vulnerable to the displacement of learning interactions by screen time. We were also surprised to see that while screen use at age 2 and 3 did not show significant links, the associations re-emerged at age 6 — when children enter formal schooling. So it is not just about early years; screen use later in childhood still matters.”
The pattern was not identical at every age. Screen viewing at ages 2 and 3 was not significantly associated with the later outcomes measured in the study, but the relationship appeared again at age 6. That timing coincides with the transition into formal education, when children face increasing demands on attention, memory, and learning.
Why the Timing of Screen Use May Matter
According to the researchers, the results support the general principle that “less is better” for children’s screen exposure. An additional hour of viewing each day may not produce an obvious effect in every individual child, but relatively small changes across an entire population could still shift a meaningful number of children toward poorer academic outcomes.
Efforts to reduce screen viewing may therefore be most useful when they begin during infancy and are reinforced as children approach school entry age. The researchers also caution that screen duration alone does not capture the full picture. Future studies should investigate whether developmental outcomes differ depending on the quality of the content children watch, the type of device being used, and whether parents watch alongside their children.
The GUSTO study was supported by the Singapore National Research Foundation and the Singapore Ministry of Health’s National Medical Research Council (NMRC/TCR/004-NUS/2008 and NMRC/TCR/012-NUHS/2014). Additional funding came from the Agence Nationale de la Recherche (ANR) in France (iSCAN project, ANR-20-CE36-0001).
