While Carr tries to ground his argument in the details of modern neuroscience, his most powerful points have nothing do with our plastic cortex. Instead, “The Shallows” is most successful when Carr sticks to cultural criticism, as he documents the losses that accompany the arrival of new technologies. The rise of the written text led to the decline of oral poetry; the invention of movable type wiped out the market for illuminated manuscripts; the television show obliterated the radio play (if hardly radio itself). Similarly, numerous surveys suggest that the Internet has diminished our interest in reading books. Carr quotes Wallace Stevens ’s poem “The House Was Quiet and the World Was Calm,” in which stillness allows the reader to “become a book.” The incessant noise of the Internet, Carr concludes, has turned the difficult text into an obsolete relic.