The Shallows: What the Internet Is Doing to Our Brains

by Nicholas Carr

When the brain is overloaded by stimuli, as it usually is when we’re peering into a network-connected computer screen, attention splinters, thinking becomes superficial, and memory suffers. We become less reflective and more impulsive. Far from enhancing human intelligence, I argue, the Internet degrades it.

McLuhan declared that the “electric media” of the twentieth century—telephone, radio, movies, television—were breaking the tyranny of text over our thoughts and senses.

McLuhan understood that whenever a new medium comes along, people naturally get caught up in the information—the “content”—it carries.

The technology of the medium, however astonishing it may be, disappears behind whatever flows through it—facts, entertainment, instruction, conversation.

Enthusiasts, with good reason, praise the torrent of new content that the technology uncorks, seeing it as signaling a “democratization” of culture. Skeptics, with equally good reason, condemn the crassness of the content, viewing it as signaling a “dumbing down” of culture.

What both enthusiast and skeptic miss is what McLuhan saw: that in the long run a medium’s content matters less than the medium itself in influencing how we think and act.

“The effects of technology do not occur at the level of opinions or concepts,” wrote McLuhan. Rather, they alter “patterns of perception steadily and without any resistance.”

In the end, we come to pretend that the technology itself doesn’t matter. It’s how we use it that matters, we tell ourselves. The implication, comforting in its hubris, is that we’re in control.

The computer screen bulldozes our doubts with its bounties and conveniences. It is so much our servant that it would seem churlish to notice that it is also our master.

Over the last few years I’ve had an uncomfortable sense that someone, or something, has been tinkering with my brain, remapping the neural circuitry, reprogramming the memory.

The Net has become my all-purpose medium, the conduit for most of the information that flows through my eyes and ears and into my mind. The advantages of having immediate access to such an incredibly rich and easily searched store of data are many, and they’ve been widely described and duly applauded.

And what the Net seems to be doing is chipping away my capacity for concentration and contemplation. Whether I’m online or not, my mind now expects to take in information the way the Net distributes it: in a swiftly moving stream of particles.

Calm, focused, undistracted, the linear mind is being pushed aside by a new kind of mind that wants and needs to take in and dole out information in short, disjointed, often overlapping bursts—the faster, the better.

For the last five centuries, ever since Gutenberg’s printing press made book reading a popular pursuit, the linear, literary mind has been at the center of art, science, and society. As supple as it is subtle, it’s been the imaginative mind of the Renaissance, the rational mind of the Enlightenment, the inventive mind of the Industrial Revolution, even the subversive mind of Modernism. It may soon be yesterday’s mind.

My life, like the lives of most Baby Boomers and Generation Xers, has unfolded like a two-act play. It opened with Analogue Youth and then, after a quick but thorough shuffling of the props, it entered Digital Adulthood.

There was something calming in the reticence of all those books, their willingness to wait years, decades even, for the right reader to come along and pull them from their appointed slots.

Reading online felt new and liberating too. Hyperlinks and search engines delivered an endless supply of words to my screen, alongside pictures, sounds, and videos. As publishers tore down their paywalls, the flood of free content turned into a tidal wave.

At first I’d figured that the problem was a symptom of middle-age mind rot. But my brain, I realized, wasn’t just drifting. It was hungry. It was demanding to be fed the way the Net fed it—and the more it was fed, the hungrier it became.

Just as Microsoft Word had turned me into a flesh-and-blood word processor, the Internet, I sensed, was turning me into something like a high-speed data-processing machine, a human HAL. I missed my old brain.

The writing ball rescued Nietzsche, at least for a time. Once he had learned touch typing, he was able to write with his eyes closed, using only the tips of his fingers. Words could again pass from his mind to the page.

Nietzsche’s prose had become tighter, more telegraphic. There was a new forcefulness to it, too, as though the machine’s power—its “iron”—was, through some mysterious metaphysical mechanism, being transferred into the words it pressed into the page.

It’s through the flow of neurotransmitters across synapses that neurons communicate with one another, directing the transmission of electrical signals along complex cellular pathways. Thoughts, memories, emotions—all emerge from the electrochemical interactions of neurons, mediated by synapses.

The brain, in the prevailing view, was something like a concrete structure. After being poured and shaped in our youth, it hardened quickly into its final form. Once we hit our twenties, no new neurons were created, no new circuits forged.

A handful of biologists and psychologists saw in the rapidly growing body of brain research indications that even the adult brain was malleable, or “plastic.” New neural circuits could form throughout our lives, they suggested, and old ones might grow stronger or weaker or wither away entirely.

As reason became the new religion of the Enlightenment, the notion of an immaterial mind lying outside the reach of observation and experiment seemed increasingly tenuous. Scientists rejected the “mind” half of Cartesian dualism even as they embraced Descartes’ idea of the brain as a machine.

The machine metaphor was extended, and further reinforced, by the arrival of the digital computer—a “thinking machine”—in the middle of the twentieth century. That’s when scientists and philosophers began referring to our brain circuits, and even our behavior, as being “hardwired,” just like the microscopic circuits etched into the silicon substrate of a computer chip.

Since the brain could not change, human nature, which emerges from it, seemed necessarily fixed and unalterable as well.”

Virtually all of our neural circuits—whether they’re involved in feeling, seeing, hearing, moving, thinking, learning, perceiving, or remembering—are subject to change. The received wisdom is cast aside.

The plasticity diminishes as we get older—brains do get stuck in their ways—but it never goes away. Our neurons are always breaking old connections and forming new ones, and brand-new nerve cells are always being created.

As the same experience is repeated, the synaptic links between the neurons grow stronger and more plentiful through both physiological changes, such as the release of higher concentrations of neurotransmitters, and anatomical ones, such as the generation of new neurons or the growth of new synaptic terminals on existing axons and dendrites.

Today, scientists sum up the essential dynamic of neuroplasticity with a saying known as Hebb’s rule: “Cells that fire together wire together.”

The plasticity of our synapses brings into harmony two philosophies of the mind that have for centuries stood in conflict: empiricism and rationalism.

In the view of empiricists, like John Locke, the mind we are born with is a blank slate, a “tabula rasa.”

In the view of rationalists, like Immanuel Kant, we are born with built-in mental “templates” that determine how we perceive and make sense of the world.

Those genetically determined connections form Kant’s innate templates, the basic architecture of the brain. But our experiences regulate the strength, or “long-term effectiveness,” of the connections, allowing, as Locke had argued, the ongoing reshaping of the mind and “the expression of new patterns of behavior.”

Some of the most extensive and remarkable changes take place in response to damage to the nervous system. Experiments show, for instance, that if a person is struck blind, the part of the brain that had been dedicated to processing visual stimuli—the visual cortex—doesn’t just go dark. It is quickly taken over by circuits used for audio processing.

As a result of such experiments, it’s now believed that the sensations of a “phantom limb” felt by amputees are largely the result of neuroplastic changes in the brain.

For as many as eight hours a day, six days a week, Bernstein used his left hand and his left leg to perform routine tasks over and over again.

The repeated actions were a means of coaxing his neurons and synapses to form new circuits that would take over the functions once carried out by the circuits in the damaged area in his brain. In a matter of weeks, he regained nearly all of the movement in his hand and his leg, allowing him to return to his everyday routines and throw away his cane.

Extensive, perpetual plasticity has been documented in healthy, normally functioning nervous systems, leading neuroscientists to conclude that our brains are always in flux, adapting to even small shifts in our circumstances and behavior.

Neuroplasticity, argues Pascual-Leone, is one of the most important products of evolution, a trait that enables the nervous system “to escape the restrictions of its own genome and thus adapt to environmental pressures, physiologic changes, and experiences.”

Playing a violin, a musical tool, had resulted in substantial physical changes in the brain. That was true even for the musicians who had first taken up their instruments as adults.

But they discovered something even more striking as well: the rakes and pliers actually came to be incorporated into the brain maps of the animals’ hands. The tools, so far as the animals’ brains were concerned, had become part of their bodies.

He found that the people who had only imagined playing the notes exhibited precisely the same changes in their brains as those who had actually pressed the keys.31 Their brains had changed in response to actions that took place purely in their imagination—in response, that is, to their thoughts.

As particular circuits in our brain strengthen through the repetition of a physical or mental activity, they begin to transform that activity into a habit. The paradox of neuroplasticity, observes Doidge, is that, for all the mental flexibility it grants us, it can end up locking us into “rigid behaviors.”

The more a sufferer concentrates on his symptoms, the deeper those symptoms are etched into his neural circuits. In the worst cases, the mind essentially trains itself to be sick.

Even very small doses of addictive drugs can dramatically alter the flow of neurotransmitters in a person’s synapses, resulting in long-lasting alterations in brain circuitry and function.

“If we stop exercising our mental skills,” writes Doidge, “we do not just forget them: the brain map space for those skills is turned over to the skills we practice instead.”

When it comes to the quality of our thought, our neurons and synapses are entirely indifferent. The possibility of intellectual decay is inherent in the malleability of our brains.

We want to believe that the impressions our brain records as sensations and stores as memories leave no physical imprint on its own structure. To believe otherwise would, we feel, call into question the integrity of the self.