More Screen Time, Lower Grades: What This 15-Year Study Revealed About Preschool Habits

Canadian researchers found that every extra hour of preschool screen time was linked to lower reading and math scores years later.

Each extra hour of daily screen time before kindergarten was linked to lower reading and math scores years later.

Healthy screen habits — less time, better content, and co-viewing — may support learning.

TORONTO — The screen time habits formed in a child’s early years may determine how well they perform in elementary school, according to a large Canadian study that tracked thousands of children from toddlerhood through sixth grade. Researchers found that the amount of time young children spent watching TV, playing on tablets, and using other digital devices prior to taking standardized tests in grades 3 and 6 predicted their reading and math scores on those tests.

For every extra hour of daily screen time during those crucial early years, children had 9 to 10 percent lower odds of scoring at a higher academic level in grade 3 reading and math, and in grade 6 math. The study, which followed more than 3,300 children and collected data from 2008 to 2023, provides some of the strongest evidence yet that what happens with screens before and during early elementary school matters for academic achievement

“High levels of screen time may displace academic-promoting activities, such as physical activity, peer play time, and sleep,” the researchers noted in their paper published in JAMA Network Open.

The preschool and early elementary school years are widely recognized as formative for brain development and learning. Children’s brains are rapidly forming connections during these periods, and their earliest experiences shape neural pathways that influence everything from language skills to attention span. This study supports concerns that flooding those formative years with screen time may interfere with the developmental building blocks children need for academic success.

Researchers from The Hospital for Sick Children in Toronto worked with the TARGet Kids! research network, which enrolls healthy children from primary care practices and follows them over time. Between 2008 and 2023, parents filled out questionnaires at routine doctor visits, reporting how much time their children spent watching TV and DVDs, playing on computers, using handheld devices like smartphones and iPads, and playing video games on a typical day.

The research team then linked this data to results from standardized tests administered by Ontario’s Education Quality and Accountability Office. These tests measure reading, writing and math skills in all third and sixth graders across the province. Students receive scores indicating whether they performed below, at, or above the provincial standard.

For children with grade three test data, screen time was measured at an average age of 5.54 years, when these preschool and kindergarten-age children were watching screens for an average of about 90 minutes per day. For children with grade six test data, screen time was measured at an average age of 7.54 years, when they averaged about 99 minutes daily.

Boys had higher screen time than girls. This was especially true for video games. About half of the participants came from families earning more than $150,000 Canadian dollars per year, and the sample was predominantly urban, which means the results may not apply equally to all populations.

The research team controlled for factors that might cloud the results (family income, parental education, ethnicity, whether the child had an individualized education plan, and what year the test was taken) to account for changes in curriculum and technology over time.

After adjusting for these variables, the pattern was clear. Each additional hour per day of total screen time was associated with 9 to 10 percent lower odds of achieving a higher academic level in grade three reading, grade three math, and grade six math. TV and digital media time showed similar associations. Notably, screen time did not appear to affect writing achievement at either grade level, nor was it associated with grade six reading achievement.

The preschool and early elementary years are when children develop the foundational skills that make formal learning possible. During this period, young brains need rich language environments filled with back-and-forth conversations, hands-on exploration of the physical world, pretend play with other children, and exposure to books and stories. Time spent on screens is time not spent on these activities.

Excessive screen time during early childhood has been linked to changes in brain structure and function in areas involved in attention, memory and executive function. These are the same cognitive abilities that children need to sit still in a classroom, follow multi-step instructions, and work through challenging problems in reading and math.

Reading skills appear especially vulnerable to high screen time during the early years. Reading development relies on early exposure to books and language-rich interactions. When a young child spends two hours watching cartoons instead of having picture books read to them, they miss out on thousands of words and questions that build vocabulary and comprehension. They lose opportunities to learn how stories work, how to turn pages, and how to associate printed letters with sounds.

Reading also requires sustained attention and active engagement with text to build comprehension and critical thinking. These cognitive skills may be disrupted when young children spend significant time with fast-paced, constantly changing screen content. Research has shown that a home literacy environment rich with print exposure and shared reading experiences is associated with greater reading and math achievement later. Screens can act as a barrier to building that environment during the years when it matters most.

Writing showed no association with screen time in this study at either grade level. The researchers speculate that writing skills may be less dependent on the home literacy environment than reading skills, and that the particular cognitive demands of writing (like handwriting fluency and spelling) may be less vulnerable to the effects of screen exposure during early childhood.

When researchers looked at video game use among young children, they found something unexpected. Video gaming was associated with lower reading achievement in grade three overall, but when the team separated boys and girls, a clear pattern emerged: video game use among girls was linked to lower reading and math scores in grade three, but the same association didn’t show up for boys.

Among grade three students, about 28 percent of boys played video games compared to only 13 percent of girls. By grade six, those numbers were 38 percent for boys and 15 percent for girls.

The researchers acknowledge that most children in their study weren’t playing video games at the young ages when screen time was measured, which may have limited their ability to detect clear patterns. They also didn’t collect detailed information about what types of games children played, such as whether they were educational, violent, or highly addictive.

Previous research on video games and academic achievement has been mixed. Some studies link gaming to lower achievement while others find no effect or even positive associations. Boys and girls tend to have different levels of interest and investment in different types of games, which could explain the gender differences observed in this study.

Screen Habits Set Early Create Long-Term Patterns One of the most important aspects of this research is that it captured screen time during early childhood and then watched to see what happened years later. Screen habits measured at various ages from infancy through early elementary school predicted test scores at ages eight to nine and ages 11 to 12. The association held up even when researchers accounted for many other factors that could explain the connection, such as family socioeconomic status and parental education. And it remained consistent across 15 years of data collection that saw dramatic changes in screen technology, from the early days of iPads to the smartphone-dominated present.

Research on early childhood development shows that behavior patterns formed during the early years are habit-forming and often persist as children grow. A three-year-old who watches three hours of screens daily is likely to become a seven-year-old who watches three hours daily, and then a teenager with the same habits.

Current pediatric guidelines from both the United States and Canada advise limiting recreational screen time for young children, but many families struggle to follow these recommendations in a world where digital devices are everywhere. The Canadian Paediatric Society recommends no screen time for children under two years old, and no more than one hour per day of high-quality programming for children aged two to five years, preferably co-viewed with parents.

Pediatric guidelines now emphasize that not all screen time is equal during the early years. Educational content watched together with a parent differs greatly from a young child passively consuming random YouTube videos alone. Interactive video calls with grandparents differ from mindless scrolling. But this study focused on total time and didn’t distinguish between high-quality and low-quality screen use.

The researchers call for future research examining not just how much time young children spend on screens, but what they’re doing on those screens and who they’re doing it with. Content, context and parental involvement all matter during these foundational years.

The study had limitations. Parents reported their children’s screen time, which can introduce bias (parents may underestimate or misremember). The sample skewed toward higher-income urban families, and children in the study scored slightly higher on standardized tests than the Ontario average, which may limit how widely the findings apply. Standardized tests themselves have limitations and may not capture the full picture of a child’s academic abilities the way teacher-assigned grades might. However, these tests do provide an objective, consistent measure that allows comparison across thousands of students and over many years. Additionally, screen time was measured at various ages depending on when children had doctor visits, ranging from infancy to around age 10, which introduces variability.

For parents of toddlers and young children navigating screen time decisions, this research offers a concrete reason to set limits early, before and during the early elementary years. What happens with screens during those formative years could shape a child’s academic trajectory through elementary school

This prospective cohort study examined children enrolled in the TARGet Kids! primary care research network in Ontario, Canada between July 2008 and June 2023. Parents completed standardized questionnaires at well-child visits, reporting their children’s daily screen time across different activities: watching TV, watching DVDs, using computers, playing video games, and using handheld devices such as smartphones and iPads. Total screen time was calculated by adding all these activities together. TV and digital media time combined TV, DVDs, computers and handheld devices. The study then linked this parent-reported data to children’s scores on provincial standardized academic achievement tests administered by the Education Quality and Accountability Office. These tests assess reading, writing and math skills in grades three and six. Researchers used the most recent screen time measurement collected before each child took their standardized test. The grade three analysis included 3,322 children with an average age of 8.86 years at testing, while the grade six analysis included 2,084 children with an average age of 11.86 years at testing. Statistical models controlled for child age, sex, ethnicity, maternal education, family income, living arrangement, year of testing, duration between screen time measurement and testing, and whether the child had an individualized education plan.

Each additional hour of total screen time per day was associated with 9 to 10 percent lower odds of achieving a higher academic level in grade three reading, grade three math, and grade six math after controlling for other factors. Similar associations were found for TV and digital media time. Video game use was associated with lower grade three reading achievement overall. No significant associations were found between screen time and writing achievement at either grade level, or between screen time and grade six reading. When researchers analyzed boys and girls separately, they found that video game use among girls was associated with lower reading and math achievement in grade three, but no such association appeared among boys. Male and female students showed similar patterns for total screen time and TV and digital media time, with higher amounts associated with lower achievement in grade three reading and math and grade six math. Screen time in the study was measured at an average age of 5.54 years for children with grade three data (with average screen time of 89.28 minutes per day) and at an average age of 7.54 years for children with grade six data (with average screen time of 98.83 minutes per day). The range of screen time measurements spanned from infancy to approximately 10 years of age.

Limitations The study has several limitations that readers should consider. As an observational study, it cannot definitively prove that screen time caused lower academic achievement, only that the two are associated. Parents self-reported their children’s screen time, which may be subject to recall bias or underreporting. The study did not collect information about the content or context of screen time, such as whether programming was educational or whether parents watched with children. TV, computer and handheld device use were combined into a single measure, which may mask differences between these activities. Social media use was not specifically examined. The study population consisted primarily of urban, higher-income families from the Toronto area, and children in the sample scored slightly higher on standardized tests than the Ontario average, which may limit how well the findings apply to other populations. Standardized tests have their own limitations and may not fully capture academic performance compared to teacher-assigned grades. Screen time was measured at various ages depending on when children had doctor visits, ranging from infancy to around age 10, which introduces variability.

This work was supported by grants from the Canadian Institutes of Health Research and the Edwin S.H. Leong Centre for Healthy Children at The Hospital for Sick Children and the University of Toronto. One of the study authors, Dr. Catherine Birken, reported receiving grants from the Heart and Stroke Foundation of Canada, Physician Services Inc., the Centre for Addiction and Mental Health, and Walmart Canada Regional Community Grant during the conduct of the study. No other authors reported conflicts of interest. The funders had no role in designing the study, collecting or analyzing data, writing the manuscript, or deciding to publish the findings.

Li X, Keown-Stoneman CD, Omand JA, Cost KT, Gallagher-Mackay K, Hove J, Janus M, Korczak DJ, Pullenayegum EM, Tsujimoto KC, Vanderloo LM, Maguire JL, Birken CS; for the TARGet Kids! Collaboration. Screen Time and Standardized Academic Achievement Tests in Elementary School. JAMA Network Open. 2025;8(10):e2537092. Published October 10, 2025. DOI:10.1001/jamanetworkopen.2025.37092

Screen time in 15 year study, and covid for four years isolation. Desensitization, no education, little socialization, isolation and despair is dangerous.

Just stare at the screen kids, all is well.

I would suggest that what the young ones do with that screen time should be considered. We allowed our young ones a lot of screen time; but, we chose most of what they did with that time. My oldest won a full scholarship through Harvard. He is a hard-driven well researched lad.

It would be interesting to compare generic HS tests from the 1940s (generally pre-television) to those of each generation thereafter.

Public School failures are the fault of teachers, administrators, states and unions. Screen time is a small factor.

I was born in 1947. There were no TV shows available for pre-school kids when I was that little. They started after I’d already entered school. My mother read to me regularly, and helped me learn how to read, so that by the time I went to Kindergarten, I was reading on my own. And because of her, I am still an avid reader at the age of 78. I was the baby, and the only one of four kids that went to college later in life. My father came to the US from Holland in 1913 at the age of 8. My mother came from Canada as a little girl in the early 1920’s. My father never finished grade school, but he could read and write well. My mother quit school at 16 to marry my father, and it wasn’t because she was pregnant. Their first child wasn’t born until 4 years later.

A little off topic.

But, I believe that addiction to electronic devices is has very much in common with alcohol or narcotic drug addiction.

Once a certain threshold of use & exposure is reached, a person’s mental and physical state is permanently altered.

Most would object to allowing children to use and become addicted to alcohol or drugs. We should apply the same concerns to electronic addiction.

But already, even before you were born technology was effecting our minds. And one time, people built things like Chaco Canyon, or Stonehenge. Even by Victorian times, our minds were too polluted to do that.

"Even by Victorian times, our minds were too polluted to do that."

Blame it on the media. There were no lying journalists when Chaco Canyon or Stonehenge were built.

Public schools fail mostly because the do what parents insist they do. Then parents fail to monitor their children or participate in their education.

And one time, people built things like Chaco Canyon, or Stonehenge.

Oh Lord! Those were not engineering feats on the scale of the Empire State Building, the Notre Dame Cathedral, Golden Gate Bridge, or any castle or fortress in Europe or the Middle East. Chaco Canyon was built only 900 years ago, and is down right pathetic compared to the Pyramids or the Colosseum in Rome, or even the interesting structures of Göbekli Tepe with are 14,000 years old.

The Chaco Canyon didn't turn up anything one of these babies, which was made early in the Victorian age:

It is a Rose Engine, which is used to create decorative pieces of many kinds. Even Queen Vicky owned one.

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