The real question we should be asking is not just, how long are they watching? But also, what are they seeing? How is it affecting them? How does what they see challenge their existing beliefs? What sort of cognitive loads and higher order thinking skills do they volunteer themselves for with their online behavior? Do we want them being told a story from a book, or creating their own story in an digital universe where they're in control? Which one more naturally creates thinking habits and behavioral shifts and skill acquisition that they can transfer to the real world?