A long-term study tracked children from infancy through age 10.5 to examine how screen time relates to learning and memory.
Researchers found the strongest links between heavier screen use at age 1 and later academic performance.
The findings suggest that when children are exposed to screens may matter as much as how much time they spend using them.
As screens have become part of everyday life, many parents have wondered how much screen time is too much.
A new study suggests that the timing of screen exposure may play an important role in children’s development. Researchers found that children who spent more time looking at screens during certain stages of early childhood, especially infancy and around the time they entered school, tended to have weaker academic performance and working memory years later.
The findings add to ongoing questions about how screens fit into healthy childhood development. Current recommendations from the World Health Organization and the American Academy of Pediatrics advise avoiding screen time before 18 to 24 months and limiting it to less than an hour a day for children ages 2 to 5.
The study
To explore the issue, researchers from Inserm and the National University of Singapore analyzed data from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) birth cohort. The study followed 502 children from infancy through middle childhood. Parents reported their children’s screen viewing time at six different ages between 1 and 8 years old.
Researchers later measured academic performance when the children were 9 years old and assessed working memory at age 10.5. Because previous research often relied on a single snapshot in time, the team wanted to examine whether different stages of childhood might represent particularly important periods for brain development.
The results
The results showed that greater screen exposure during infancy and around age 6 was consistently linked with poorer academic performance and weaker working memory later on.
The strongest associations appeared among children who spent more time viewing screens at age 1. Interestingly, screen use at ages 2 and 3 did not show the same pattern, but the associations resurfaced around school-entry age.
Researchers also found that children with higher screen exposure across childhood generally performed less well academically.
"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 authors say the findings suggest that early childhood may be a sensitive period for cognitive development and that screen habits established during those years could have lasting effects. They noted that future studies should examine factors beyond screen duration, including the type of content children are viewing, the devices they use and whether parents are watching alongside them.