I've watched about the first 5-6 minutes and will watch the rest later today. I may have to get the book. Because i have so many questions about how he reached his conclusions.
Firstly did he look at whether there are cultural (due to ethnicity, religion, or where the kids actually grew up) and/or economic factors, because not all families can afford the best, and generally expensive tech. Secondly i would argue tech was impacting us all long before high speed internet.
My Gen X sons pleaded for one of the early Atari game systems with 'cassettes' (that actually plugged into the power unit in much the same way flash drives did to computers later). Having read that some games good for hand eye motor co-ordination issues which they'd been diagnosed with i saved up and got it for like their 8th birthday i think. But unlike a lot of parents i had rules. Game time was earned (completing homework primarily) and not unlimited.
By the time my Millennial daughter was in 2nd grade she was being introduced to computers at school, and the boys were getting some use in school library. I did most of my late in life college papers on a word processing electric typewriter. The ease of editing was tge big draw for me. All three of kids by the time they were ten their favorite way to spend 'free time' was reading. In 6th grade school tests showed both boys were reading at master's level, when DD hit that test the school could not find a 'frustration level' for her.
However, i still encouraged interacting with nature via beach, park and with daughter after we moved to Wyoming--hiking trips. When we got a home computer time on it was limited and the computer was in living room where i might peek over her shoulder at any time, until she was 18.
As with most of life, balance is a good thing. I believe in allowing kids opportunities to learn, test their physical capabilities/limits but also their mental/emotional ones. But parents should keep eyes open, some of the 'freedoms' we enjoyed also could have put us in danger of not just getting 'hurt' but much more lethal consequences. How many cold cases 'solved' or covered because still unsolved have been told since 2000 that involve victims who were Gen X or Boomer kids who didn't come home one night when the street lights came on???
We discussed books, movies and tv shows. It was a way a could gauge their development but also interesting and enjoyable. Despite one of my boys bragging at summer camp that they could talk to me about anything, they never lost sight of my role as both 'authority figure' and protector.
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Post millennium both tech and social media of course had bigger influences on young but that was largely due to two factors.
1) While many parents have become overprotective about physical risks, many of them have not bothered to discuss with and monitor the emotional risks of social media. If the Mean-girl clique at school criticizes someone's clothing style that can be hurtful, but it easier to get for a parent to help them put it into perspective than if a selfie she posts gets hundreds or thousands of views but half or more are negative.
2) In a weird way the ability to instantly almost constantly connect with others has also tended to isolate us from family and neighbors (not all of us course, but too many). When i worked at UW i was saddened to see groups of students sitting together in the student union and all of them in phones and barely talking to each other. Then I noticed over the years that in restaurants, mall food courts i would see families behaving the same way-- on their 'devices', sometimes not even paying enough attention to toddlers, as long as the child didn't fuss or cry. Because parents got sucked down the tech rabbit holes (games and social media) too.