Blocking mobile internet on smartphones improves sustained attention, mental health, and subjective well-being
Noah Castelo et al. PNAS Nexus. .
Abstract
Smartphones enable people to access the online world from anywhere at any time. Despite the benefits of this technology, there is growing concern that smartphone use could adversely impact cognitive functioning and mental health. Correlational and anecdotal evidence suggests that these concerns may be well-founded, but causal evidence remains scarce. We conducted a month-long randomized controlled trial to investigate how removing constant access to the internet through smartphones might impact psychological functioning. We used a mobile phone application to block all mobile internet access from participants' smartphones for 2 weeks and objectively track compliance. This intervention specifically targeted the feature that makes smartphones "smart" (mobile internet) while allowing participants to maintain mobile connection (through texts and calls) and nonmobile access to the internet (e.g. through desktop computers). The intervention improved mental health, subjective well-being, and objectively measured ability to sustain attention; 91% of participants improved on at least one of these outcomes. Mediation analyses suggest that these improvements can be partially explained by the intervention's impact on how people spent their time; when people did not have access to mobile internet, they spent more time socializing in person, exercising, and being in nature. These results provide causal evidence that blocking mobile internet can improve important psychological outcomes, and suggest that maintaining the status quo of constant connection to the internet may be detrimental to time use, cognitive functioning, and well-being.
© The Author(s) 2025. Published by Oxford University Press on behalf of National Academy of Sciences.
Figures
Attention, mental health, and SWB improve after 2 weeks of blocking mobile internet. In the Intervention group, participants blocked mobile internet access from T1 to T2. In the Delayed Intervention group, participants blocked mobile internet access from T2 to T3. Error bars depict adjusted within-subjects SEs (26).
Mechanisms linking blocked mobile internet access to SWB and mental health. Blocking mobile internet increased time spent in the offline world, decreased media consumption (across any device), improved social connectedness and self-control, and increased nightly hours of sleep. Each of these effects, in turn, improved SWB and mental health.
CONSORT diagram.
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