JONATHAN HAIDT: American parenting really changed in the 1990s. When I'm talking about the book I go around the country, I ask audiences: At what age were you let out? At what age could you go outside and play with your friends with no adults supervising? And I say, "Only people over 40 what's your answer? Call it out." And it's: "Five, seven, eight, six, five, seven!" It's always five to eight. That's what we always did — between five and eight kids could go outside without an adult. They would get in arguments, they would play games, they would make rules, they were independent; they got years and years of practicing independence. Then I say: "Just people under 25 what year were you let out?" "12, 14, 13, 16!" Nobody says ten or younger. In the 1990s, as the crime rate was plummeting, as American life was getting safer and safer, Americans freaked out and thought that if they take their eyes off their children the children will be abducted. Now this goes back — the fear was stoked by cable TV in the 1980s, there were a few high profile of abductions, but it's not until the 1990s that we really start locking kids up and saying you cannot be outside until you're 14 or 15.

We took this essential period of childhood, from about eight to 12, when kids throughout history have practiced independence, have gotten into adventures, have made rafts and floated down the Mississippi River — we took that period and said you don't get to practice independence until it's too late, until that period is over. Now, a couple years before you go to college, now you can go outside. "Okay, go off to college." And a lot of them are not ready. They're just not used to being independent. When they get to college they need more help, they're asking adults for more help. "Protect me from this. Punish him for saying that. Protect me from that book."

There's a very sharp change with kids who were born in 1995 and afterwards — surprisingly sharp. Jean Twenge in her book iGen analyzes surveys of behavior of time use and beginning with kids born in 1995, they spend a lot less time going out with friends, they don't get a drivers license as often, they don't drink as much, they don't go out on dates, they don't work for money as much. What are they doing? They're spending a lot more time sitting on their beds with their devices interacting that way. These are the first kids who got social media when they were 13, roughly. They were subjected to much more anti-bullying content in their schools, much more adult supervision, they were raised in the years after 9/11, they were given much less recess and free play with no child left behind, there was much more testing pushed down into earlier grades.

We don't know if this is for sure the reason, but they seem to have more difficulty working out problems on their own. The most common thing I hear is that members of Gen Z, if they overhear a joke, if they overhear someone say something, they'll get offended and then they'll go straight to HR, they go straight to somebody to file a complaint, where previous generations would have either just shaken it off or just said "jerk" or "asshole" or whatever.

I think there are a couple of things we can say. One is you have to take charge of device use and social media. We don't know for sure but it looks like a two-hour limit per day is probably a good idea; keeping kids off of social media as long as possible is a good idea. It's very hard to do this as one parent when your kid's friends are not limited. So you've got to talk to your kid's friends and all have a common front, all have a common policy then go to the schools. Schools can solve these problems collectively in ways that individual parents cannot.

Outside of school go to Letgrow.org, an organization, a wonderful new organization started by Lenore Skenazy who wrote the book Free-range Kids. She became famous as America's worst mom because in 2009 she let her nine-year-old son ride the New York City subway. Not only did he survive, he was thrilled. He felt he learned something. He felt he could go out into the world. Give childhood back to kids so that they do what they most need to do, which is develop the skills of being an independent adult. Remember that the job of a parent is to work him or herself out of a job.