Summary: A new study has demonstrated that the timing of childhood screen exposure is just as critical to long-term cognitive development as the total volume of daily viewing hours. Collaborating neuroscientists and pediatric researchers monitored 502 children over nearly a decade, evaluating screen habits at six distinct intervals between ages 1 and 8.
The data revealed that elevated screen use during infancy (age 1) and around formal school-entry (age 6) consistently predicted lower academic performance at age 9 and demonstrably weaker working memory capacity at age 10.5. Conversely, screen use at ages 2 and 3 did not yield statistically significant long-term academic correlations, isolating early infancy and school-entry as vulnerable developmental windows.
Key Facts
- The “U-Shaped” Sensitivity Re-emergence: Long-term cognitive deficits were driven primarily by exposure during two critical periods: infancy (age 1) and school entry (age 6), while mid-toddlerhood (ages 2–3) showed muted long-term academic impacts.
- Infancy is the Highest Risk Window: Screen exposure at 12 months produced the largest negative effect sizes on future working memory and learning outcomes across the entire study duration.
- The Displacement Effect: High infancy screen viewing actively displaces critical face-to-face, reciprocal learning interactions that are structurally required to wire the rapidly developing baby brain.
- Working Memory Impairment: Excess screen exposure was directly tied to measurable declines in working memory at age 10.5, undermining the exact cognitive workspace needed for reading comprehension, mathematical calculations, and complex problem-solving.
- Population-Level Public Health Risk: While an additional hour of screen time may only marginally alter an individual child’s trajectory, the authors warn that at a population scale, this modest shift drags a significant percentage of children down into lower academic testing brackets.
Source: Zhejiang University
As screens become nearly universal in young children’s lives, questions about their long-term impact on learning have grown more urgent.
A new longitudinal study followed children from age 1 to 8 years and found that higher screen viewing time—particularly during infancy and around school-entry age—was consistently associated with poorer academic performance at age 9 and weaker working memory at age 10.5. The findings suggest that the timing of screen exposure may be as important as the amount of screen time itself.
The World Health Organization (WHO) and the American Academy of Pediatrics recommend no screen time before 18–24 months and less than one hour per day for children ages 2 to 5. Yet many young children exceed these limits, and evidence on how screen viewing affects cognitive development has been mixed.
Most studies have been cross-sectional, focused on school-age children, or lacked repeated measurements across early childhood. Longitudinal studies spanning multiple developmental stages are therefore needed to identify potentially sensitive periods of exposure and better account for family and environmental influences.
A team of researchers from Inserm and the National University of Singapore conducted the study, which was published online ahead of print on April 9, 2026, in the World Journal of Pediatrics.
Using data from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort, they analyzed parent-reported screen time at six time points and assessed children’s academic achievement and working memory several years later.
The study followed 502 children from infancy through middle childhood and found that higher screen viewing time during certain developmental periods was associated with poorer later academic performance and weaker working memory. The associations were most consistent for screen exposure during infancy and around school-entry age, suggesting that these stages may represent particularly sensitive windows for cognitive development.
Children with higher overall screen exposure across childhood also tended to perform less well academically. The findings indicate that the timing of screen use may matter as much as the total amount of exposure, with early childhood appearing to be a critical period when screen habits could have lasting implications for learning and memory.
“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 findings support the principle that “less is better” when it comes to children’s screen time, the authors said. While an individual child might not experience noticeable harm from an extra hour of daily viewing, even modest shifts at the population level could move a meaningful number of children toward lower academic performance.
Public health interventions aimed at reducing screen time may benefit from starting early—during infancy—while also reinforcing limits around school entry age. The authors emphasize that future research should examine not only the duration of screen use but also factors such as content quality, device type, and parental co-viewing, which may influence developmental outcomes.
Funding information
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).
Key Questions Answered:
A: At 12 months old, the infant brain is undergoing an unparalleled wave of synaptic growth and requires rich, responsive, three-dimensional human interactions to map language, spatial awareness, and focus. Screens are inherently non-reciprocal. When an infant is placed in front of a screen, it causes what neuroscientists call “the displacement effect”, it physically steals time away from the real-world social interactions and hands-on explorations that are foundational to wiring early memory and learning architecture.
A: The researchers were highly surprised by the non-linear, re-emerging pattern of vulnerability. While screen use at age 1 caused major long-term damage, screen habits at ages 2 and 3 showed no significant statistical links to future academic performance. However, the exact moment the children turned 6 and entered formal schooling, the negative associations flared up again. This proves that screen habits remain a major risk factor later in childhood, directly interfering with the brain’s adjustment to structured classroom environments.
A: Not necessarily on an individual, isolated basis. The researchers emphasized that the effect size for a single child might be subtle or difficult to notice day-to-day. Instead, this is a major public health warning for entire communities. When millions of young children are exposed to excessive screen time, it shifts the entire population’s academic curve downward, meaning a massive, measurable number of children who would have performed excellently are pushed into lower categories of academic achievement and working memory capacity.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this neurodevelopment and memory research news
Author: Editorial Office
Source: Zhejiang University
Contact: Editorial Office – Zhejiang University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Screen viewing time from age 1 to 8 years and subsequent academic performance and working memory” by Shuai Yang, Natarajan Padmapriya, Saw Seang-Mei, Chong Yap Seng, Lynette P. Shek, Peter D. Gluckman, Keith M. Godfrey, Johan G. Eriksson, Falk Müller-Riemenschneider, Evelyn C. Law & Jonathan Y. Bernard. World Journal of Pediatrics
DOI:10.1007/s12519-026-01046-1
Abstract
Screen viewing time from age 1 to 8 years and subsequent academic performance and working memory
Background
Screen viewing time is associated with children’s academic and cognitive outcomes, but longitudinal studies are scarce, hindering identification of the most sensitive age periods. We assessed the associations of single and cumulative average screen viewing time with academic performance and working memory.
Methods
In the Growing Up in Singapore Towards healthy Outcomes birth cohort, parents reported their child’s screen viewing time at ages 1, 1.5, 2, 3, 6 and 8 years. At ages 9 and 10.5, trained psychologists assessed academic performance (Wechsler Individual Achievement Test-Third Edition) and working memory (Letter-Number Sequencing task; Wechsler Intelligence Scale for Children-Fifth Edition). Associations of single and cumulative average screen viewing time with psychological outcomes were examined by multivariable linear regression (N = 502 children).
Results
Mean (standard deviation) screen viewing time ranged from 2.1 (2.0) hours/day at age 1 year, to 3.0 (2.2) hours/day at 8 years. In unadjusted models, higher screen viewing time from age 1 to 8 years was consistently associated with poorer academic performance at age 9 years and working memory at 10.5 years.
After adjustment, effect sizes were reduced, but higher screen viewing time at ages 1 year [β = – 1.47, 95% confidence interval (CI): – 2.37 to – 0.57 standard points per additional hour per day], 1.5 years (β = – 0.95, 95% CI: – 1.85 to – 0.06), and 6 years (β = – 0.88, 95% CI: – 1.55 to – 0.21) had persisting associations with poorer academic performance at age 9 years.
Greater screen viewing time at ages 1 year (β = – 1.12, 95% CI: – 2.07 to – 0.17) and 6 years (β = – 1.01, 95% CI: – 1.71 to – 0.31) was associated with poorer working memory at age 10.5 years. Cumulative average exposure models showed that screen viewing time over childhood was consistently associated with poorer academic performance but not working memory.
Conclusion
In this longitudinal study, cumulative average screen viewing time was associated with lower academic performance but not working memory, with the strongest effect sizes seen for single screen viewing time occurring in early infancy.
