Why paper books beat screens for learning (backed by research)

I have somewhere between 60 and 70 shelves of books in this house, well over a thousand of them, in several languages, and I have finally started cataloguing the lot. Going through them reminded me why paper still matters to me. The research is fairly clear that we retain more from paper than from a screen, and I think the reason is simple. When it is just you and the book in your hands, there is nowhere else to go, no pixels, no navigating, no temptation to scroll away. When did you last read a paper book for three hours straight?