Nicholas Carr’s bestseller ‘The Shallows’ has become a foundational book in one of the most important debates of our time: As we enjoy the internet’s bounties, are we sacrificing our ability to read and think deeply?

Here are excerpts from the book:

“GARY SMALL, A professor of psychiatry at UCLA and the director of its
Memory and Aging Center, has been studying the physiological and neurological
effects of the use of digital media, and what he’s discovered backs up
Merzenich’s belief that the Net causes extensive brain changes. “The current
explosion of digital technology not only is changing the way we live and
communicate but is rapidly and profoundly altering our brains,” he says. The
daily use of computers, smartphones, search engines, and other such tools
“stimulates brain cell alteration and neurotransmitter release, gradually
strengthening new neural pathways in our brains while weakening old ones.”

In 2008, Small and two of his colleagues carried out the first experiment that
actually showed people’s brains changing in response to Internet use.
Theresearchers recruited twenty-four volunteers—a dozen experienced Web surfers
and a dozen novices—and scanned their brains as they performed searches on
Google. (Since a computer won’t fit inside a magnetic resonance imager, the
subjects were equipped with goggles onto which were projected images of Web
pages, along with a small handheld touchpad to navigate the pages.) The scans
revealed that the brain activity of the experienced Googlers was much broader
than that of the novices. In particular, “the computer-savvy subjects used a
specific network in the left front part of the brain, known as the dorsolateral
prefrontal cortex, [while] the Internet-naïve subjects showed minimal, if any,
activity in this area.” As a control for the test, the researchers also had the
subjects read straight text in a simulation of book reading; in this case, scans
revealed no significant difference in brain activity between the two groups.
Clearly, the experienced Net users’ distinctive neural pathways had developed
through their Internet use.
The most remarkable part of the experiment came when the tests were
repeated six days later. In the interim, the researchers had the novices spend an
hour a day online, searching the Net. The new scans revealed that the area in
their prefrontal cortex that had been largely dormant now showed extensive
activity—just like the activity in the brains of the veteran surfers. “After just five
days of practice, the exact same neural circuitry in the front part of the brain
became active in the Internet-naïve subjects,” reports Small. “Five hours on the
Internet, and the naïve subjects had already rewired their brains.” He goes on to
ask, “If our brains are so sensitive to just an hour a day of computer exposure,
what happens when we spend more time [online]?”

One other finding of the study sheds light on the differences between reading
Web pages and reading books. The researchers found that when people search
the Net they exhibit a very different pattern of brain activity than they do when
they read book-like text. Book readers have a lot of activity in regions associated
with language, memory, and visual processing, but they don’t display much
activity in the prefrontal regions associated with decision making and problem
solving. Experienced Net users, by contrast, display extensive activity across all
those brain regions when they scan and search Web pages. The good news here
is that Web surfing, because it engages so many brain functions, may help keep
older people’s minds sharp. Searching and browsing seem to “exercise” the brain
in a way similar to solving crossword puzzles, says Small.
But the extensive activity in the brains of surfers also points to why deep
reading and other acts of sustained concentration become so difficult online. The
need to evaluate links and make related navigational choices, while also
processing a multiplicity of fleeting sensory stimuli, requires constant mental
coordination and decision making, distracting the brain from the work of
interpreting text or other information. Whenever we, as readers, come upon a
link, we have to pause, for at least a split second, to allow our prefrontal cortex
to evaluate whether or not we should click on it. The redirection of our mental
resources, from reading words to making judgments, may be imperceptible to us
—our brains are quick—but it’s been shown to impede comprehension and
retention, particularly when it’s repeated frequently. As the executive functions
of the prefrontal cortex kick in, our brains become not only exercised but
overtaxed. In a very real way, the Web returns us to the time of scriptura
continua, when reading was a cognitively strenuous act. In reading online,
Maryanne Wolf says, we sacrifice the facility that makes deep reading possible.
We revert to being “mere decoders of information.”
Our ability to make the rich mental connections that form when we read deeply and without distraction remains largely disengaged.”

(The 2020 edition of this book is available at