We can think about maturity not only in terms of physical development but also brain development and in terms of mental and emotional maturity. Girls reach full maturity in terms of brain development by about 22 years of age; boys not until about 25 years. (Location 219)

Scholars generally agree that the purpose of our species’ prolonged childhood and adolescence is enculturation:18 the process of acquiring all the skills and knowledge and mastering all the customs and behaviors required for competency in the culture in which you live. It takes years to master the details of Japanese language, culture, and behavior; the same is true of Swiss language, culture, and behavior. If you or I were to move to Kyoto or to Appenzell as adults, we might struggle for the rest of our lives to master the intricacies of the language, the local arts, the local culture. We would likely always feel like outsiders, even if we did manage to master at least the language after 20 years or so. (Location 248)

Once a young woman is 22 years of age, once a young man is 25, it becomes harder to master fully a new language, a new culture, a new life. (Location 257)

We now live in a culture in which kids value the opinion of same-age peers more than they value the opinion of their parents, a culture in which the authority of parents has declined not only in the eyes of children but also in the eyes of parents themselves. (Location 306)

For most of the history of the human race, children have learned culture from the adults. That’s why childhood and adolescence have to last so long in our species. But in the United States today, kids no longer learn culture from the grown-ups. American kids today have their own culture, a culture of disrespect, which they learn from their peers and which they teach to their peers. (Location 351)

What does it mean to assert your authority as a parent? It doesn’t necessarily mean being a tough disciplinarian. Among other things, it means ensuring that the parent-child relationship takes priority over the relationships between the child and her or his same-age peers. (Location 388)

When the culture values youth over maturity, the authority of parents is undermined. Young people easily overestimate the importance of youth culture and underestimate the culture of earlier generations. “Why should we have to read Shakespeare?” is a common refrain I hear from American students. “He is so totally irrelevant to, like, everything.” (Location 431)

But Megan is mistaken. Courtney isn’t independent. No 12-year-old truly is. Instead, Courtney has transferred her natural dependence from her parents, where it should be, to her same-age peers, where it shouldn’t be. Courtney’s top priorities now lie in pleasing her friends, being liked by her friends, being accepted by same-age peers. Her parents have become an afterthought, a means to other ends. (Location 455)

“Nevertheless, despite your protests, you are going to come with us.” But that’s what you must say. Why? Because having fun together is one foundation of authoritative parenting in the modern world. Because if most of the good times come when kids are having fun with other kids, then it’s no wonder that kids don’t want to spend more time with adults. Because your kids won’t value time with you above time with same-age peers if they rarely spend any time with you doing fun stuff. That’s part of what it means to exercise parental authority. (Location 460)

Too often, parents today allow their desire to please their child to govern their parenting. If your relationship with your child is governed by your own desire to be loved by him or her, the odds are good that you will not achieve even that objective. (Location 489)