If you’ve been paying attention, you know that Twitter, that phenomenal purveyor of 140-character messages about everything from Justin Bieber to the Arab Spring, has recently given birth to a new mobile app called Vine. It’s basically tweets for video: Each endlessly looping clip is limited to six seconds long. Six seconds. Just enough time to say, for instance, “I’m Mike Wallace, and this is 60 Minutes.” (Who really needs those other 59 minutes and 54 seconds?)

I assumed at first that Vine was something the editors of the Onion had dreamed up, but it’s real — or what passes for real in the Internet age. Just a few weeks old, Vine is already filled with stop-action cartoons, cat videos and, of course, porn.

The sparkly ephemera of modern life are usually easy to laugh off. But once in a while, you confront something that suggests the darker implications of racing along at such a pace, amid such a flurry of distractions and demands. On Feb. 3, The New York Times ran a devastating 6,500-word front-page story about a young man named Richard Fee who had become addicted to an attention-deficit drug. He hanged himself last year. The story used Fee’s death to explore the alarming increase in ADHD prescriptions. Tens of millions of Americans now swallow these pills every day to help themselves concentrate. Some experts warn that many of these prescriptions are not medically justified.

In 1985, Neil Postman warned that we were amusing ourselves to death. But now there’s nothing amusing about it. We’re literally distracting ourselves into early graves.

While the intensity of the problem may be unprecedented, our anxiety about the effects of too many distractions has deep roots in American culture. Long before Angry Birds, we had angry philosophers.

Henry David Thoreau fled the hubbub of Concord, Mass. in 1845 to “simplify, simplify, simplify.” Discovering that the three rocks he was using as paperweights had to be dusted, he threw them out his cabin window. “So with a hundred modern improvements,” he wrote. “Our inventions are wont to be pretty toys, which distract our attention from serious things.” (When he died, Thoreau left behind a journal of 2 million words — the equivalent of 100,000 tweets.)

Anyone who teaches children or teens is familiar with the broad questionnaires sent in from family psychiatrists. The good doctors want to know if Johnny — the patient is usually male — ever has trouble concentrating in class. Does he ever stare off during an explanation of dangling participles or a quiz on “The Scarlet Letter”?

When I was teaching English and filling out those forms, almost every student could have fallen within the broad parameters of “distracted.” And that was before we had Draw Something on our iPhones.

A hundred years before Pinterest, Henry Adams was linked in to the accelerating pace of modern life. Awed by a whirling electrical generator, he looked at what had happened over the previous century and made a bold prediction: “At the rate of progress since 1800, every American who lived into the year 2000 would know how to control unlimited power. He would think in complexities unimaginable to an earlier mind.”

Like, say, tweeting during “Dancing With the Stars” while texting a friend about some new shoes on Zappos.

Confronted by e-mail, Facebook postings and Four Square updates, anyone over 40 risks sounding like a Luddite. Adams, as always, was right: “In every age man has bitterly and justly complained that Nature hurried and hustled him.” But with every new social media platform that taxes our attention, it’s worth reconsidering Thoreau’s eerily prescient complaint about the very first form of electronic communication: “We are in great haste to construct a magnetic telegraph from Maine to Texas,” he wrote in 1832, “but Maine and Texas, it may be, have nothing important to communicate.”

Clearly, Thoreau never anticipated that someday he might get to see Katy Perry tweet: “I am severely embarrassed that I just now discovered the Ikea monkey.”

But not all the warnings about our distracted lives are buried in 19th-century open-access e-texts (what we used to call “books”). In 1989, a then-unknown writer named Sue Bender published a bestseller called “Plain and Simple.” (You can get “free” wireless delivery via Amazon Whispernet for $8.89.) Struck by the beauty of Amish handiwork, Bender wrote, “My life was like a CRAZY QUILT, a pattern I hated. Hundreds of scattered, unrelated, stimulating fragments, each going off in its own direction, creating a lot of frantic energy.” That same year, an Internet company called America Online announced, “Welcome! You’ve got mail.”

A quarter century later, millions of people have bought anti-distraction apps such as Freedom ($10) or Concentrate ($29) that block their access to the Internet for a set length of time. And when those e-solutions fail, too many young people stop playing Words With Friends and have some words with friends: ADHD pills are easily, if illegally, available in the dorm.

Now that science has enabled us to tinker with the very chemistry of our brains, perhaps we have more reason than ever to resist, to slow down, to unhook, and tune out — if only for a few hours. After all, what sort of society encourages healthy young people to routinely medicate themselves into a state of concentration?

As Willy Loman’s wife implored, “Attention must be paid.”

But we need to keep our eye on the price.