I had this study confused with Feeds, Feelings & Focus and was really sad I lost it.

quotes

• 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.
• 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.
• …90% of American adults own a smartphone, and the average user spends 4.6 h per day on their device. At the same time, there is increasing public concern about how this technology might negatively affect people: half of American smartphone users—and more than four out of five users under age 30—worry that they use their device too much…