Reading on smartphone affects sigh generation, brain activity, and comprehension
It's not only comprehension decline, it's a combination of decreasing attention spans and the substitution of your memory by an electronic device (calendar, notes, etc.). I've been writing about what's happened to me during the COVID lockdowns, and I think quite a few of HN people share the feeling that one can barely even read a normal book at length these days... Here's my actual writeup from back in early 2021: https://www.lostbookofsales.com/age-of-distractions/