Every claim. Every source.
Every statistic on this site is linked to its original study, report, or official record. Nothing is asserted without evidence.
The Science
The prefrontal cortex — which supports impulse control, judgement and planning — develops mainly through adolescence and is not fully mature until around the age of 25.
Arain M, Haque M, Johal L, et al. — Maturation of the adolescent brain. Neuropsychiatric Disease and Treatment, 2013
https://doi.org/10.2147/NDT.S39776Adolescence is a highly sensitive period of brain development, when the brain is especially susceptible to social pressure, peer opinion and peer comparison. The Surgeon General notes that young people mature at different rates, and that some are more vulnerable than others to the content and features of social media platforms.
U.S. Surgeon General’s Advisory — Social Media and Youth Mental Health, 2023
https://www.hhs.gov/sites/default/files/sg-youth-mental-health-social-media-advisory.pdfWHO recommends no screen time for infants under 1, advises against sedentary screen time at age 1, and sets a maximum of one hour a day, with less better, for ages 2–4. The guidelines cover children under 5.
World Health Organization — Guidelines on Physical Activity, Sedentary Behaviour and Sleep for Children Under 5 Years of Age, 2019
https://www.who.int/publications/i/item/9789241550536
By the Numbers
Children aged 8–12 in the US spend an average of 5.5 hours per day on entertainment screen media — not including school-related use.
Common Sense Media — The Common Sense Census: Media Use by Tweens and Teens, 2021
https://www.commonsensemedia.org/research/the-common-sense-census-media-use-by-tweens-and-teens-202142% of US teen girls reported persistent sadness or hopelessness in 2021 — the highest rate recorded in a decade.
Centers for Disease Control and Prevention — Youth Risk Behaviour Surveillance Survey, 2021
https://www.cdc.gov/mmwr/volumes/72/su/su7201a3.htmScreen addiction and device overuse ranked as the single top health concern among US parents — above childhood obesity, bullying, and depression.
C.S. Mott Children's Hospital National Poll on Children's Health / Ipsos, 2023
https://mottpoll.org/reports/overuse-devices-and-social-media-top-parent-concernsYouTube was fined $170 million by the Federal Trade Commission in 2019 for illegally collecting personal data from children under 13 without parental consent — the largest COPPA violation ever recorded.
Federal Trade Commission press release, September 2019
https://www.ftc.gov/news-events/news/press-releases/2019/09/google-youtube-will-pay-record-170-million-alleged-violations-childrens-privacy-law1 in 5 tweens aged 8–12 report more than 8 hours of daily entertainment screen use.
Common Sense Media — The Common Sense Census: Media Use by Tweens and Teens, 2021
https://www.commonsensemedia.org/research/the-common-sense-census-media-use-by-tweens-and-teens-2021YouTube generated $31.5 billion in advertising revenue in 2023.
Alphabet Inc. Annual Report (Form 10-K), 2023
https://abc.xyz/assets/43/44/675b83d7421999f07bfce503d0b6/2023-annual-report.pdf
The Effects
Blue light from screens suppresses melatonin production. Evening device use before bed can delay sleep onset by up to 90 minutes compared to reading under low light.
Chang AM, Aeschbach D, Duffy JF, Czeisler CA — Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Proceedings of the National Academy of Sciences (PNAS), 2015
https://www.pnas.org/doi/10.1073/pnas.1418490112Greater screen time at age 1 is associated with a dose-response increase in communication and problem-solving delays at ages 2 and 4 — with risk rising with each additional hour per day.
Takahashi I et al. — Screen Time at Age 1 Year and Communication and Problem-Solving Developmental Delay at 2 and 4 Years. JAMA Pediatrics, 2023
https://jamanetwork.com/journals/jamapediatrics/fullarticle/2808593Higher amounts of screen time in early childhood are associated with weaker language skills. Co-viewing educational content with a caregiver moderates this effect.
Madigan S, McArthur BA, Anhorn C, Eirich R, Christakis DA — Associations Between Screen Use and Child Language Skills: A Systematic Review and Meta-Analysis. JAMA Pediatrics, 2020
https://jamanetwork.com/journals/jamapediatrics/fullarticle/2764488
Built to Be Addictive
Notification timing, like batching and delaying engagement signals, is deliberately engineered to maximise dopamine response. Former Meta employees testified to these practices before the US Senate.
Testimony of Frances Haugen before the Senate Commerce Subcommittee on Consumer Protection, October 2021
https://www.commerce.senate.gov/2021/10/testimony-of-frances-haugen
What You Can Do
WHO recommends no screen time for infants under 1, advises against sedentary screen time at age 1, and sets a maximum of one hour a day, with less better, for ages 2–4. The guidelines cover children under 5.
World Health Organization — Guidelines on Physical Activity, Sedentary Behaviour and Sleep for Children Under 5 Years of Age, 2019
https://www.who.int/publications/i/item/9789241550536
Behind Your Action Plan
WHO: no screen time for infants under 1; sedentary screen time is not recommended at age 1; no more than one hour a day, and less is better, at ages 2–4.
World Health Organization — To grow up healthy, children need to sit less and play more, April 2019
https://www.who.int/news/item/24-04-2019-to-grow-up-healthy-children-need-to-sit-less-and-play-moreFor children under 18 months, the American Academy of Pediatrics advises avoiding screen media other than video chatting with family and friends.
American Academy of Pediatrics, Council on Communications and Media — Media and Young Minds, 2016
https://publications.aap.org/pediatrics/article/138/5/e20162591/60503/Media-and-Young-MindsFor ages 5–18 the AAP says the evidence does not support a one-size-fits-all approach. It recommends a Family Media Use Plan with consistent limits on hours and types of media; an hour of daily physical activity and 8–12 hours of sleep; no devices in bedrooms and no screens for the hour before bed; media-free times such as family dinner; no entertainment media during homework; and the same rules from every caregiver.
American Academy of Pediatrics, Council on Communications and Media — Media Use in School-Aged Children and Adolescents, 2016
https://publications.aap.org/pediatrics/article/138/5/e20162592/60321A meta-analysis of 20 studies of 6–19-year-olds found that bedtime access to and use of a media device was associated with inadequate sleep, poorer sleep quality and excessive daytime sleepiness.
Carter B, Rees P, Hale L, Bhattacharjee D, Paradkar MS — Association Between Portable Screen-Based Media Device Access or Use and Sleep Outcomes. JAMA Pediatrics, 2016
https://jamanetwork.com/journals/jamapediatrics/fullarticle/2571467Self-reported media use correlates only moderately with logged use (mean r = 0.38); the authors conclude self-reports are rarely an accurate reflection of what the logs show.
Parry DA, Davidson BI, Sewall CJR, Fisher JT, Mieczkowski H, Quintana DS — A systematic review and meta-analysis of discrepancies between logged and self-reported digital media use. Nature Human Behaviour, 2021
https://www.nature.com/articles/s41562-021-01117-5In interviews with 27 parents and a diary study of 28 families with children aged 1–5, ending screen time was often painful. It went more smoothly when the technology provided a natural stopping point such as the end of an episode or playlist, when screen time was routine rather than ad hoc, and when the technology rather than the parent ended it. Autoplay and suggested videos made limits harder to hold. Countdown warnings were not associated with smoother endings.
Hiniker A, Suh H, Cao S, Kientz JA — Screen Time Tantrums: How Families Manage Screen Media Experiences for Toddlers and Preschoolers. CHI 2016
https://faculty.washington.edu/alexisr/ScreenTimeTantrums.pdfParents’ own screen time, and their attitudes towards screens, are associated with how much screen time their young children have.
Lauricella AR, Wartella E, Rideout VJ — Young children’s screen time: The complex role of parent and child factors. Journal of Applied Developmental Psychology, 2015
https://doi.org/10.1016/j.appdev.2014.12.001Social media may perpetuate body dissatisfaction, disordered eating behaviors, social comparison and low self-esteem, especially among adolescent girls.
U.S. Surgeon General’s Advisory — Social Media and Youth Mental Health, 2023
https://www.hhs.gov/sites/default/files/sg-youth-mental-health-social-media-advisory.pdf
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