Moderate use was not harmful — and the harm at high use was small
A study of over 120,000 adolescents testing whether screen time has a sweet spot
Reviewed by Sian Trombley, CCCFounder, Thrive Family Company
Moderate confidence
Source citation
Przybylski A. K., Weinstein N. (2017). A Large-Scale Test of the Goldilocks Hypothesis: Quantifying the Relations Between Digital-Screen Use and the Mental Well-Being of Adolescents. Psychological Science. https://doi.org/10.1177/0956797616678438
Published 1 January 2017 · Added to Thrive 26 July 2026 · Reviewed 26 July 2026
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Rather than asking whether screens are bad, this study asked how much is too much, and how much the answer matters.
Published research findings
The study
Przybylski and Weinstein analysed self-reported screen use and wellbeing in a national sample of more than 120,000 English fifteen-year-olds.
What researchers examined
Whether the relationship between screen use and wellbeing was linear or curved.
What they found
Wellbeing rose slightly with moderate use, then declined gradually at higher levels. Even at the extremes, screen use explained a very small share of differences in wellbeing.
Thrive editorial interpretation
What this may mean for families
Blanket limits are less useful than attention to sleep, activity and what the screen displaces.
What this doesn't tell us
Important limitations
Cross-sectional and self-reported, so it cannot show what causes what.
Evidence confidence describes how much weight this study's design can carry — not how strongly the finding applies to any individual child or family.
Therapist perspective — Thrive interpretation, not a finding of the study
Therapist Perspective
Ask what the screen is replacing. That question is more diagnostic than any number of hours.
Practical family considerations
Ask what screen time is displacing, not just how long it lasts.
This research summary is educational and does not replace individualized medical, psychological or therapeutic advice.
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Adolescents' Perspectives on Self-Regulation and Need for Change in Digital Media Use: A Focus Group Study
2026 · Research article
Emerging evidence
Why it matters
The findings suggest the findings have implications for research, education, parenting, and policy focused on supporting adolescents' development in digital contexts. This does not establish what will happen in any individual family.
Screen time explains far less about teenage wellbeing than the headlines suggest
2019 · Cross-sectional study
Moderate confidence
Why it matters
Total screen hours is a weak target. Sleep, comparison and what happens on the phone are better places to spend household energy.