n spent on TV watching was probably very high as well. I think passive entertainment where you are just injesting and not having to really do anything with it has always been a problem even if you go back to radio, heck reading can be considered passive if done in a certain way. The portablity and ease is a problem but the root is humans always wanting to have a path of least resistance, technology has just gotten to a certain point. That's why I think just listening to lectures only, watching a youtube video or listening to a podcast isn't really a valid way of learning something you have to work through it explain it to others, do sample problems about it (think text books with problems), struggle with it instead of passively letting the words just flow past you for the most part. I'd be interested to see if retention is higher in reading actually physical books rather than audio books.