”Jean Twenge and I have had a lot of disagreement on this.” FWIW I am convinced that Twenge is on to something. We know blue light disrupts sleep, we know that the constant availability changes relationships, we know (with some confidence) that online interactions pull for more sadism and narcissism, etc. Screen time for young people is probably a net bad thing, and possibly a very bad thing. In my current opinion (very familiar w/ the literature), screen time + social media is probably net bad for young brains, mental health, relationships, and civic engagement.