There’s a website that algorithmically recommends books to its users. I input my desired genre, pace and page length, and a whole roster of precisely tagged and well-endorsed options load onto the screen. It turns an old-fashioned conversation with a librarian into a high-speed search. But when standing in a bookshop later the same day, not one of the suggested titles springs to mind. The search begins all over again.

This is “digital amnesia”—the phenomenon of people forgetting stuff that’s instantly, technologically available to them. It’s why we defer to Google Maps in cities we’ve lived in for years, and can’t string together a sentence in Spanish despite our unbroken Duolingo streak. There’s a flavor of absurdism to this micro memory loss, like forgetting lines on...