Study finds teens spend nearly one-third of the school day on smartphones, with frequent checking linked to poorer attention
A new study from researchers at University of North Carolina at Chapel Hill finds that middle and high school students spend nearly one-third of the school day on their smartphones, checking them dozens of times, often for social media and entertainment, with frequent checking linked to weaker attention and impulse control.
The research examined how often adolescents use their phones during school and whether that behavior is related to their ability to focus and regulate attention. By objectively tracking smartphone use every hour over a two-week period, the study generated thousands of real-world data points, allowing researchers to see how phone use unfolds throughout the school day rather than relying on self-reports or daily averages.
“Smartphones are no longer something students use occasionally during school—they’re present during every hour of the day,” said Eva Telzer, professor of psychology and neuroscience at UNC-Chapel Hill and lead author of the study. “Our findings show that frequent phone checking may undermine the very skills students need to succeed in the classroom.”
The study found that students who checked their phones more frequently showed poorer cognitive control, a key skill for learning and academic success.
“What surprised us most was the sheer amount of time teens are on their phones during school,” said Kaitlyn Burnell, research assistant professor at UNC-Chapel Hill and co-author of the study. “Students were on their phones every hour during school, spending one-third of the school day on their phones, with social media and entertainment accounting for over 70% of their time.”
By capturing phone use moment to moment, the researchers were able to identify frequent checking, not just total screen time, as a critical behavior linked to attention fragmentation and weaker self-control. This distinction is important, as it suggests that interruptions caused by repeated phone checking may be particularly disruptive to learning.
“As states and school districts across the country adopt new phone policies, our findings provide support for limiting access to smart phones during school hours” said Telzer. “Policies that restrict access to highly reinforcing platforms, including social media and entertainment apps, during instructional time may help protect students’ attention and academic engagement.”
The findings provide concrete, objective evidence that can inform future school policies and digital literacy programs, offering a path toward more targeted approaches to managing smartphones in educational settings while preserving the benefits of technology when used intentionally.
The research paper is available online in JAMA.
Journal
JAMA
Article Title
Smartphone Use During School Hours and Association With Cognitive Control in Youths Aged 11 to 18 Years
Article Publication Date
9-Mar-2026
Smartphone use during school hours and association with cognitive control in youths ages 11 to 18
JAMA Network Open
About The Study:
This cross-sectional study found that youths use smartphones approximately one-third of the school day; this use was associated with reduced cognitive control. These findings highlight the need for school-level policies and digital literacy programs that address not only overall screen time but also habitual smartphone-checking behaviors that fragment attention.
Corresponding Author: To contact the corresponding author, Eva H. Telzer, PhD, email ehtelzer@unc.edu.
To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/
(doi:10.1001/jamanetworkopen.2026.1092)
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
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About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.
Journal
JAMA Network Open
Students with lower self-control tend to procrastinate with short-form video; sleep suffers, but not grades, study finds
Young people who use social media to escape also tend to use short videos to put off responsibilities
University of Kansas
LAWRENCE — Who among us hasn’t put off doing something we know we need to do while scrolling through just a few more TikToks, Instagram reels or YouTube shorts?
New research from the William Allen White School of Journalism & Mass Communications at the University of Kansas has found that college students with lower self-control, stronger habitual short-form video use and who tended to use them to escape and fulfill the need to belong were prone to procrastinating via such short clips.
While the behaviors did not appear to negatively affect students' grades, procrastinatory short-form video use was found to be associated with worse sleep health and higher stress.
Researchers and parents alike have been warning of problematic media use for decades, whether it is too much TV or too much gaming. However, limited research has established the connection between short-form video use and its effects on young people’s well-being — although it is known unhealthy social media habits can foster procrastination, which in turn can lead to negative psychological and behavioral outcomes.
In one of her classes, Yunwen Wang asked students what time they went to bed the night before.
“Very few students, only two in a classroom of over 100, went to bed before 10 p.m. I thought that was a very alarming moment, especially concerning how TikTok and YouTube shorts are gaining in popularity. In media psychology, a concept called ‘flow’ describes when audiences enter a moment of full immersion and lose track of time,” said Wang, assistant professor of journalism & mass communications at KU and an author of the study. “That happens when users enjoy the media and when the activity carries either high mental weight requiring concentration or little mental weight as the repetitive behavior creates automaticity, such as automatic scrolling of short-form videos.
“In the past, there were diversified ways of interacting with different media, but now, because of the ease of use of these mobile apps and social media platforms, they are becoming more dominant over other hobbies that college students have,” Wang said. “Research on problematic media use isn’t a new thing, but by extending the area to these emerging platforms with short-form videos, we are addressing a gap in current research.”
For the study, Wang and co-author Danny Yihan Jia of Boston University surveyed more than 500 students from KU and Boston University. They asked students about their use of short-form videos, personal and health traits, and academic performance. The study was published in the journal Cyberpsychology, Behavior and Social Networking.
Students were asked about how they viewed short-form videos, both in normal use and in procrastinatory ways. They were also asked about how frequently they engaged and their motivations for doing so, such as escapism, entertainment or to feel a sense of belonging. Researchers also considered the effects of short-form video use by asking about four aspects of sleep health and levels of stress.
Short-form videos and sleep quality
Results showed that students who had lower self-control and more habitual use of short-form videos also reported poorer sleep health and higher levels of stress. Sleep health was poorer in terms of perceived sleep quality overall, when they went to sleep, how often they woke up during the night and how well they functioned on days after a poor night’s sleep.
“We found that the lower the self-control, the more likely the students will develop procrastinatory short-form video use,” Wang said. “And the motivation to enjoy, escape and feel socially connected also contributed to the procrastination behavior. Ultimately, the more procrastinatory short-form video consumption, the higher the stress level and the worse the sleep health among these students.”
Effects on academic performance
Researchers also examined the association between short-form video use and academic performance. Students were asked about their grade point average on a 4.0 scale. Results, however, did not show an association between procrastinatory short-form video use and diminished GPA. That does not mean one should infer problematic short-form video use cannot or does not affect academic achievement, the researchers wrote, but it could indicate that they sampled from a high-achieving group of students or that the sample is not representative of the broader young population across the country.
Wang also emphasized that while the associations between procrastinatory short-form video use and lower sleep health and higher stress were strong, it should not be assumed that TikTok, Instagram Reels, YouTube Shorts or the like are the sure cause. Some respondents indicated they use such media when they are having trouble sleeping. College students are often under stress for academic, social, financial and other reasons and may use such short-form videos to escape unpleasant realities of life.
However, the connections should also not be ignored or simply accepted as the state of media that young people consume today.
“College students especially are in an important transitional and developmental stage of life,” Wang said.
Research recommendations
The KU researcher said both institutions of higher learning and society at large could help by providing more holistic mental health and student health outreach services. Beyond simply informing young people that problematic use of social media could be harmful, those developing such approaches could collaborate with young people to learn more about their needs and how best to serve them.
While problematic media use is not new, the short-form video dynamic is relatively new, and more research could help add to the understanding of its detriments, which could inform strategies to understand motivations, reduce procrastinatory uses of media as well as help form healthier media habits, Wang said.
“The novel contribution of our work is understanding motivators and consequences of problematic media use and that we are bridging the gap by testing this paradigm on emergent platforms of short-form videos,” Wang said. “My research area is at the intersection of computer-mediated communication and human-computer interaction. The next emergent technology that could be studied would be agentic AI serving as social companions, friends, partners or collaborators. Students who grow up with it are going to become used to using it for everything from academics to asking general questions and perhaps then addressing those conditions like loneliness and friendship.”
Journal
Cyberpsychology Behavior and Social Networking
Method of Research
Survey
Subject of Research
People
Article Title
Endless Scrolling: Predictors of Procrastinatory Short-Form Video Use and Its Effects on Stress and Sleep
Digital media use and child health and development
JAMA Pediatrics
News ReleaseAbout The Study:
In this systematic review and meta-analysis, digital media use was consistently associated with risks to child and adolescent health and development, particularly for social media. These findings highlight the need for targeted, multifaceted policies and interventions to mitigate potential harms from digital media exposure.
Corresponding Author: To contact the corresponding author, Samantha Teague, PhD, email sam.teague@jcu.edu.au.
To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/
(doi:10.1001/jamapediatrics.2026.0085)
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
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Journal
JAMA Pediatrics
