“in a phone-based childhood, children are plunged into a whirlpool of adult content and experiences that arrive in no particular order. Identity, selfhood, emotions, and relationships will all be different if they develop online rather than in real life. What gets rewarded or punished, how deep friendships become, and above all what is desirable—all of these will be determined by the thousands of posts, comments, and ratings that the child sees each week. Any child who spends her sensitive period as a heavy user of social media will be shaped by the cultures of those sites. This may explain why Gen Z’s mental health outcomes are so much worse than those of the millennials: Gen Z was the first generation to go through puberty and the sensitive period for cultural learning on smartphones.”