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 .
