The Internet may cause our minds to wander off, and yet a quick look at the history of books suggests that we have been wandering off all along. When we read, the eye does not progress steadily along the line of text; it alternates between saccades—little jumps—and brief stops, not unlike the movement of the mouse’s cursor across a screen of hypertext. From the invention of papyrus around 3000 B.C., until about 300 A.D., most written documents were scrolls, which had to be rolled up by one hand as they were unrolled by the other: a truly linear presentation. Since then, though, most reading has involved codices, bound books or pamphlets, a major advantage of which (at least compared to the scroll) is that you can jump around in them, from chapter to chapter (the table of contents had been around since roughly the first century B.C.); from text to marginal gloss, and, later, to footnote.
In the age of print, nonlinear reading found its most elaborate support in the “book wheel,” invented by the Italian engineer Agostino Ramelli in 1588: a “rotary reading desk” which allowed the reader to keep a great number of books at once, and to switch between them by giving the wheel a turn. The book wheel was— unfortunately!—a rarity in European libraries, but when you think about all the kinds of reading that print affords, the experience of starting a text at its beginning and reading all the way to the end, which we now associate with “deep” reading, looks less characteristic of print in general than of the novel in particular: the one kind of book in which, we feel, we might be depriving ourselves of something vital if we skipped or skimmed.
The quality of digital media poses one kind of problem for the reading brain; the quantity of information available to the wired reader poses a different and more serious problem. But it’s worth noting that readers have faced this problem before, too. Gutenberg printed his first Bible in 1455, and by 1500, some 27,000 titles had been published in Europe, in a total of around 10 million copies. The flood of printed matter created a reading public, and changed the way that people read.