Preteens who use increasing amounts of social media perform poorer in reading, vocabulary and memory tests in early adolescence compared to those who use little or no social media. A study published in JAMA examined data from over 6,000 children ages 9 to 10 through early adolescence. Researchers classified the children into three groups: 58% used little or no social media over several years, 37% started with low-level use but spent about an hour daily on social media by age 13, and 6% spent three or more hours daily by that age.

Even low users who spent about one hour per day performed 1 to 2 points lower on reading and memory tasks compared to non-users. High users performed 4 to 5 points lower than non-social media users. Jason Nagata, a pediatrician at the University of California, San Francisco and study author, said the findings were notable because even modest social media use correlated with lower cognitive scores.