Children who spent more time in front of screens at age 1 — and again around the start of formal schooling at age 6 — went on to show weaker working memory and lower academic performance years later, according to a study published this week in the World Journal of Pediatrics.
Researchers from Inserm and the National University of Singapore tracked 502 children in the GUSTO birth cohort, a long-running Singapore study, recording parent-reported screen viewing time at six points between infancy and age 8. They then compared that history against academic performance measured at age 9 and working memory tests given at age 10.5.
The strongest associations turned up at the earliest measurement. "The effect sizes we saw at age 1 were the largest among all time points we examined," the researchers said, pointing to infancy as a period of heightened sensitivity to environmental influences on brain development. Associations largely faded for screen time recorded at ages 2 and 3, then reappeared around age 6, as children entered primary school.
An association, not proof of cause
The study establishes a correlation rather than a proven causal mechanism, and it relied on parents' own reports of their children's screen time rather than objective measurement such as device logs. With 502 children, the cohort is also modest by the standards of large epidemiological studies, and the researchers did not publish precise effect-size figures in the summaries of the work released so far. The authors said future work should account for the type of content children watched, the device used, and whether a parent was watching alongside them — factors other pediatric research has suggested can change how screen exposure affects development, since passive video-watching and interactive, co-viewed use are not equivalent exposures.
The findings feed into an ongoing debate over pediatric screen-time guidance. Public health bodies have generally advised limiting screen exposure for children under 2 aside from video calls, though researchers say longitudinal cohort studies like this one are still filling in exactly when, and how, early exposure affects later development. Coverage of the study, first reported by ScienceDaily this week, noted the Singapore team's next step is examining specific content types and co-viewing patterns to sharpen that guidance.
