A friend asked me about a book I had read, and whether I would recommend it to her. I drew a complete blank on what I did and didn’t like about it. Embarrassed by my lack of retention, I pulled it off the shelf to try and give myself a quick refresher. As it turns out, pulling it off the shelf was pretty much all I needed to do. The mere act of picking up the book and looking at its cover was enough to trigger a bunch of memories. Flipping through the pages, scanning over the layout, the chapter headings, even just the typeface — everything about the book served to remind me of the contents, to the point where I barely even needed to look at the text itself to remember what it was about.
This is why print books are still valuable. They are their own mnemonic devices.