Today, a counterrevolution is under way. As the computer and cell phone become our main reading devices, the book is being pushed to the periphery of culture. According to recent studies by Ball State University and the federal government,
the average American spends more than eight hours a day peering into a screen - TV, computer or cell phone (sometimes all three at once) - but devotes just 20 minutes to reading books and other printed works. Reading from a screen is very different from reading from a book. A book provides a shield against distraction, allowing us to focus our entire attention on an author's narrative or argument. When text is put onto a screen, it enters what the science fiction writer Cory Doctorow terms an "ecosystem of interruption technologies." The words have to compete for our attention with links, e-mails, texts, tweets, Facebook updates, videos, ads and all the other visual stimuli that pour through our computers.
In a very real sense, screen reading is returning us to that distant time when there were no spaces between words.
Reading is again becoming a cognitively strenuous job as the mind struggles to keep track not only of the words but also of all the surrounding distractions. The best our overloaded brains can do is skim and scan. Maryanne Wolf, a developmental psychologist at Tufts University and an expert on the neuroscience of reading, notes that learning to read deeply is a painstaking process, requiring changes deep in our brains. She worries that the shift from immersive page-based reading to distracted screen-based reading could impede the development of the specialized neural circuits that make richly interpretive reading possible. We might turn back into mere "decoders" of text.
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/06/20/INL91DU44K.DTL