Smartphone use among adolescents during school hours: High-intensity objective observations across different...

Adolescent smartphone use in school and how it shapes learning and development have attracted substantial attention. Yet, objective data on digital behavior during school hours are limited. This study uses high-intensity smartphone observations from 139 13-17-year-olds (Mage = 15.52; 47.2% female) in the United States over six months between 2021 and 2022 to examine patterns across face-to-face, online, and blended instructional contexts. Use duration was significantly longer during online instruction (Median = 133.50 mins) and shorter during face-to-face (Median = 70.74 mins), compared to non-school days (Median = 92.38 mins). Use was often off-task, with social media being the most used. Two case studies highlight idiosyncrasies in use. Findings highlight the contextual, personalized nature of smartphone use during school hours and inform educational policy.