JAMA Netw Open

Smartphone use fills one third of school day for U.S. youths

March 12, 2026

A cross‑sectional study tracked hourly iPhone screen time for 79 youths aged 11 to 18 years across 14 school days and found that participants used smartphones for about one third of the school day (mean, 2.22 hours). Older teens (15–18 years) logged nearly double the in‑school use of younger adolescents. Social media comprised the largest share, and students checked their devices an average of 64 times during school hours. More frequent checking was associated with lower inhibitory control.

Clinical takeaway: Counsel families that habitual phone‑checking during school may be associated with weaker cognitive control and discuss strategies to support healthier in‑school device habits.

Source:

Telzer EH, Burnell K. (2026, March 2). JAMA Netw Open. Smartphone Use During School Hours and Association With Cognitive Control in Youths Aged 11 to 18 Years. https://pubmed.ncbi.nlm.nih.gov/41801197/