The Shallows: What the Internet Is Doing to Our Brains

by Nicholas Carr

Plastic does not mean elastic, in other words. Our neural loops don’t snap back to their former state the way a rubber band does; they hold onto their changed state. And nothing says the new state has to be a desirable one. Bad habits can be ingrained in our neurons as easily as good ones. Pascual-Leone observes that “plastic changes may not necessarily represent a behavioral gain for a given subject.” In addition to being “the mechanism for development and learning,” plasticity can be “a cause of pathology.”35 It comes as no surprise that neuroplasticity has been linked to mental afflictions ranging from depression to obsessive-compulsive disorder to tinnitus. 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. Many addictions, too, are reinforced by the strengthening of plastic pathways in the brain. 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. In some cases, the buildup of certain kinds of neurotransmitters, such as dopamine, a pleasure-producing cousin to adrenaline, seems to actually trigger the turning on or off of particular genes, bringing even stronger cravings for the drug. The vital paths turn deadly. The potential for unwelcome neuroplastic adaptations also exists in the everyday, normal functi...

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