Smartphone Use in School Affects Learning and Cognitive Development: Study

Findings come as the first social media addiction lawsuit trial is underway in California state court, involving claims that platforms fostered addiction in children to increase profits.

A new study indicates teens spend about one-third of their school day checking and using their smartphones, a habit that greatly impacts their learning and behavior.

Researchers from the University of North Carolina published the findings in JAMA Network Open on March 9, after discovering that youth spent more than two hours of every school day using their smartphones, which has led to fragmented attention spans and weaker impulse control.

Health experts have long warned that excessive smartphone and social media use may harm child development, increasing risks of anxiety, depression, sleep disruption and feelings of isolation. Some research has also linked heavy social media use to increased suicide risk among adolescents.

A study published in February found that teens who spend more than 16 hours per week on social media, roughly two hours per day, face a significantly higher risk of loneliness and depression.

Researchers say these risks may be amplified by platform features designed to maximize engagement, such as algorithm-driven feeds, autoplay videos and infinite scrolling. Adolescents are considered particularly vulnerable because developing brains are more sensitive to social feedback and reward-based stimuli.

These findings come as a number of social media addiction lawsuits move forward in courts across the United States. The lawsuits each raise similar allegations that platforms like Facebook, Instagram, TikTok and YouTube intentionally design algorithms to maximize engagement, particularly among children, who experts say are more vulnerable to addiction.

Led by Dr. Eva H. Telzer, researchers from the University of North Carolina, Chapel Hill, studied 79 teens ages 11 to 18 years from the Southeastern United States. They assessed smartphone use for 14 consecutive days during two different time periods from April 2021 to February 2022, and from February 2023 to December 2024.

Researchers used Apple iPhone iOS screen time reports to capture smartphone use at every hour and provide thousands of data points of actual engagement. They also measured cognitive control.

The data indicates students spent one-third of their school day using smartphones. The detailed monitoring helped the researchers determine that the students used their phones during every hour of the school day, spending a total of 2.22 hours on average on their smartphones per day. Roughly 70% of their time was spent on social media or entertainment apps.

Teens checked their phones 64 times during school hours, with researchers observing that the teens who checked their phones more often were more likely to score lower on cognitive function and indicators of poorer cognitive control.

Older teens ages 15 to 18 spent more time on their smartphones during school than teens 11 to 14 years old. The older teens averaged 23 minutes per hour compared to 11 minutes per hour for younger teens.

Researchers concluded frequent smartphone use can impact learning and cognitive development. They also emphasized a need for school policies to address screen use and programs to improve digital literacy and habitual smartphone-checking behaviors.

Social Media Addiction Lawsuits

With parents, school districts and states indicating they are impacted by teens’ excessive social media use, a growing number of social media addiction lawsuits have been filed against platforms such as Facebook, Instagram, TikTok, Snapchat and YouTube. 

Social media platforms currently face more than 2,300 lawsuits pending in the Northern District of California before U.S. District Judge Yvonne Gonzalez Rogers, where the court has been presiding over coordinated discovery and pretrial proceedings over the past few years. The first two federal social media addiction bellwether cases are scheduled to go to trial in the summer of 2026.

The complaints allege that addictive algorithms knowingly designed by TikTok, Meta, Snap and Google to maximize user engagement have encouraged compulsive use and contributed to serious mental health problems among children and young adults, including loneliness, depression, eating disorders, suicide attempts and completed suicides.

However, the first social media lawsuit trial is currently underway in California state court. The outcomes of these trials will be closely watched, as they may provide insight on how juries will interpret evidence and testimony likely to be similar or identical across the litigation. It is hoped that the results could form the basis of a social media addiction settlement agreement.

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