The Shallows: What the Internet is Doing to Our Brains

by Nicholas Carr

Our genes “specify” many of “the connections among neurons—that is, which neurons form synaptic connections with which other neurons and when.” 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.”

the sensations of a “phantom limb” felt by amputees are largely the result of neuroplastic changes in the brain.

It’s not just repeated physical actions that can rewire our brains. Purely mental activity can also alter our neural circuitry, sometimes in far-reaching ways.

our thoughts can exert a physical influence on, or at least cause a physical reaction in, our brains. We become, neurologically, what we think.

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.”33 The chemically triggered synapses that link our neurons program us, in effect, to want to keep exercising the circuits they’ve formed. Once we’ve wired new circuitry in our brain, Doidge writes, “we long to keep it activated.”

The potential for unwelcome neuroplastic adaptations also exists in the everyday, normal functioning of our minds. Experiments show that just as the brain can build new or stronger circuits through physical or mental practice, those circuits can weaken or dissolve with neglect. “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.”

the tools man has used to support or extend his nervous system—all those technologies that through history have influenced how we find, store, and interpret information, how we direct our attention and engage our senses, how we remember and how we forget—have shaped the physical structure and workings of the human mind. Their use has strengthened some neural circuits and weakened others, reinforced certain mental traits while leaving others to fade away. Neuroplasticity provides the missing link to our understanding of how informational media and other intellectual technologies have exerted their influence over the development of civilization and helped to guide, at a biological level, the history of human consciousness.

The written word liberated knowledge from the bounds of individual memory and freed language from the rhythmical and formulaic structures required to support memorization and recitation.

Sumerians were the first to use a specialized medium for writing. They etched their cuneiform into carefully prepared tablets made of clay, an abundant resource in Mesopotamia.

Around 2500 BC, the Egyptians began manufacturing scrolls from the papyrus plants that grew throughout the Nile delta.

These bound tablets, popular in their own right, served as a model for an anonymous Roman artisan who, shortly after the time of Christ, sewed several sheets of parchment between a pair of rigid rectangles of leather to create the first real book.

The lack of word separation, combined with the absence of word order conventions, placed an “extra cognitive burden” on ancient readers,

The Bible, which took at least three years to produce, was Gutenberg’s triumph. It was also his undoing. In 1455, having printed just two hundred copies, he ran out of money. Unable to pay the interest on his loans, he was forced to hand his press, type, and ink over

The steep reduction in the cost of manufacturing books was amplified by the growing use of paper, an invention imported from China, in place of more costly parchment.

When our brain is overtaxed, we find “distractions more distracting.”17 (Some studies link attention deficit disorder, or ADD, to the overloading of working memory.) Experiments indicate that as we reach the limits of our working memory, it becomes harder to distinguish relevant information from irrelevant information, signal from noise. We become mindless consumers of data.

learning facts and concepts will be worse if you learn them while you’re distracted,” said the lead researcher, UCLA psychologist Russell Poldrack.32 On the Net, where we routinely juggle not just two but several mental tasks, the switching costs are all the higher.

“The more you multitask, the less deliberative you become; the less able to think and reason out a problem.” You become, he argues, more likely to rely on conventional ideas and solutions rather than challenging them with original lines of thought.

We can assume that the neural circuits devoted to scanning, skimming, and multitasking are expanding and strengthening, while those used for reading and thinking deeply, with sustained concentration, are weakening or eroding.

Lewis Mumford’s observation that “no computer can make a new symbol out of its own resources” remains as true today as when he said it in 1967.63

Short-term memories don’t become long-term memories immediately, and the process of their consolidation is delicate. Any disruption, whether a jab to the head or a simple distraction, can sweep the nascent memories from the mind.16

Storing long-term memories requires the synthesis of new proteins. Storing short-term memories does not.

The Web provides a convenient and compelling supplement to personal memory, but when we start using the Web as a substitute for personal memory, bypassing the inner processes of consolidation, we risk emptying our minds of their riches.

“For a memory to persist,” writes Kandel, “the incoming information must be thoroughly and deeply processed. This is accomplished by attending to the information and associating it meaningfully and systematically with knowledge already well established in memory.”35 If we’re unable to attend to the information in our working memory, the information lasts only as long as the neurons that hold it maintain their electric charge—a few seconds at best. Then it’s gone, leaving little or no trace in the mind.

The influx of competing messages that we receive whenever we go online not only overloads our working memory; it makes it much harder for our frontal lobes to concentrate our attention on any one thing. The process of memory consolidation can’t even get started. And, thanks once again to the plasticity of our neuronal pathways, the more we use the Web, the more we train our brain to be distracted—to process information very quickly and very efficiently but without sustained attention.

Every tool imposes limitations even as it opens possibilities. The more we use it, the more we mold ourselves to its form and function.

McLuhan’s point was that an honest appraisal of any new technology, or of progress in general, requires a sensitivity to what’s lost as well as what’s gained.

A team of University of Michigan researchers, led by psychologist Marc Berman, recruited some three dozen people and subjected them to a rigorous, and mentally fatiguing, series of tests designed to measure the capacity of their working memory and their ability to exert top-down control over their attention. The subjects were then divided into two groups. Half of them spent about an hour walking through a secluded woodland park, and the other half spent an equal amount of time walking along busy downtown streets. Both groups then took the tests a second time. Spending time in the park, the researchers found, “significantly improved” people’s performance on the cognitive tests, indicating a substantial increase in attentiveness. Walking in the city, by contrast, led to no improvement in test results.