There is an interesting connection between ebooks and memory. There are comments on this in many places (Scholarly Kitchen, Time, Scientific American) but Verlyn Klinkenborg sums it up nicely:
I finish reading a book on my iPad — one by Ed McBain, for instance — and I shelve it in the cloud. It vanishes from my “device” and from my consciousness too. It’s very odd.
This is familiar to those who read ebooks but it is really not that strange. Despite being different contents the ebook text lacks dimensions and differences that help our memories. Books have different covers, fonts, layouts, graphical elements, paper quality and more. They are marked by use: Old books are creased and sometimes stained. There may be a coffee stain on a page in your favorite book that will evoke a memory of the reader spilling coffee while reading. While attempting to find a passage in a paper book we can remember how far in the book the text appeared, that it was on the left or right and whether it was at the top of the page or not.
These dimensions are not available in ebooks. Most readers have only one font. Layouts barely vary, and if you have a stain on the screen, it appear on every page. All the ebooks weigh the same, look the same and smell the same. Only the text (not the font) varies. Because of this we struggle to remember texts we read in ebooks and this also effects our ability to understand new texts.
While I recognize the issue when it comes to ebooks. Does it really have the same effect with other e-reading? Many of us spend most of our days reading of screens. Blogs, emails and Wikipedia. Not to mention all the time we spend on online news and reading/re-reading our own writing. Are these more or less forgetful, compared with their physical counterparts? Or does the geography and variation of the web enable us to remember these more.
Is it not e-reading in general that makes us forget, but rather the poor design & format of the medium that hinders our memory? It could be that the screen based format is not the optimal for longer continuous texts.