I'd add that I also think there is a three dimensional cataloging of information that you get from using a thick textbook. "Chapter 19" gets stored in your own

I'd add that I also think there is a three dimensional cataloging of information that you get from using a thick textbook. "Chapter 19" gets stored in your own memory in three dimensional space. Flipping backwards and forwards on topics can result in an unintentional mnemonic device. Especially when you consider a typical introduction to of comp-sci textbook (for example) the foundational principles (input, output, variables, loops) are all organized at the FRONT of the book. Things of increasing complexity are gated behind the foundations. Now that's also probably just a window into how my 40 year old brain grew up. With textbooks etc... there's nothing to say that younger brains won't re-wire themselves to learn from a screen and find their own mnemonics - maybe it's left and right as opposed to forward and back.