Interesting! Do you then move on to reading "normally" after applying this method to the first few pages? Seems tough to stick with for a whole reading session.

Reading physical books also may to be correlated to higher, active comprehension: "human beings need a knowledge of where they are in time and space that allows them to return to things and learn from re-examination" (article with related discussion https://readup.com/comments/the-guardian/skim-reading-is-the...)