Ms Claire Handscombe has a commitment problem online. Like a lot of Web surfers, she clicks on links posted on social networks, reads a few sentences, looks for exciting words and then grows restless, scampering off to the next page she probably won't commit to.
"I give it a few seconds - not even minutes - and then I'm moving again," said Ms Handscombe, a 35-year-old graduate student in creative writing at American University.
But it's not just online any more. She finds herself behaving the same way with a novel.
"It's like your eyes are passing over the words but you're not taking in what they say," she confessed. "When I realise what's happening, I have to go back and read again and again."
To cognitive neuroscientists, Ms Handscombe's experience is the subject of great fascination and growing alarm. Humans, they warn, seem to be developing digital brains with new circuits for skimming through the torrent of information online.
This alternative way of reading is competing with traditional deep reading circuitry developed over several millennia.
"I worry that the superficial way we read during the day is affecting us when we have to read with more in-depth processing," said Dr Maryanne Wolf, a Tufts University cognitive neuroscientist and the author of Proust And The Squid: The Story And Science Of The Reading Brain.
If the rise of non-stop cable TV news gave the world a culture of sound bites, the Internet, Dr Wolf said, is bringing about an eye-byte culture. Time spent online - on desktop and mobile devices - was expected to top five hours a day last year for US adults, according to eMarketer, which tracks digital behaviour. That's up from three hours in 2010.
Word lovers and scientists have called for a "slow reading" movement, taking a branding cue from the "slow food" movement. They are battling not just cursory sentence-galloping but also the constant social network and e-mail temptations that lurk on our gadgets - the bings and dings that interrupt "Call me Ishmael".
Researchers are working to get a clearer sense of the differences between online and print reading - comprehension, for starters, seems better with paper - and are grappling with what these differences could mean not only for enjoying the latest Pat Conroy novel, but also for understanding difficult material at work and school.
There is concern that young children's affinity and often mastery of their parents' devices could stunt the development of deep reading skills.
The brain is the innocent bystander in this new world. It just reflects how we live.
"The brain is plastic its whole life span," Dr Wolf said. "The brain is constantly adapting."
Dr Wolf, one of the world's foremost experts on the study of reading, was startled last year to discover her brain was apparently adapting, too. After a day of scrolling through the Web and hundreds of e-mails, she sat down one evening to read Hermann Hesse's The Glass Bead Game.
"I'm not kidding: I couldn't do it," she said. "It was torture getting through the first page. I couldn't force myself to slow down so that I wasn't skimming, picking out key words, organising my eye movements to generate the most information at the highest speed. I was so disgusted with myself."
The brain was not designed for reading. There are no genes for reading like there are for language or vision. But spurred by the emergence of Egyptian hieroglyphics, the Phoenician alphabet, Chinese paper and, finally, the Gutenberg press, the brain has adapted to read.
Before the Internet, the brain read mostly in linear ways - one page led to the next page, and so on. Sure, there might be pictures mixed in with the text, but there didn't tend to be many distractions. Reading in print even gave us a remarkable ability to remember where key information was in a book simply by the layout, researchers said. We'd know a protagonist died on the page with the two long paragraphs after the page with all that dialogue.
The Internet is different. With so much information, hyperlinked text, videos alongside words and interactivity everywhere, our brains form short cuts to deal with them all - scanning, searching for key words, scrolling up and down quickly.
This is non-linear reading, and it has been documented in academic studies. Some researchers believe that for many people, this style of reading is beginning to invade when dealing with other mediums as well.
"We're spending so much time touching, pushing, linking, scrolling and jumping through text that when we sit down with a novel, your daily habit of jumping, clicking, linking is just ingrained in you," said Professor Andrew Dillon, a University of Texas lecturer who studies reading.
"We're in this new era of information behaviour, and we're beginning to see the consequences of that."
Dr Wolf did not scoff at someone who finds it easier to follow links than to keep track of clauses in page after page of long paragraphs. She offered more evidence: Several English department chairs from around the country have e-mailed her to say their students are having trouble reading the classics.
"They cannot read Middlemarch. They cannot read William James or Henry James," Dr Wolf said. "I can't tell you how many people have written to me about this phenomenon. The students no longer will or are perhaps incapable of dealing with the convoluted syntax and construction of George Eliot and Henry James."
She points out that she's no Luddite. She sends e-mails from her iPhone as often as her students. She's involved with programmes to send tablets to developing countries to help children learn to read. But just look, she said, at Twitter and its brisk 140-character declarative sentences.
"How much syntax is lost, and what is syntax but the reflection of our convoluted thoughts?" she said. "My worry is we will lose the ability to express or read this convoluted prose. Will we become Twitter brains?"
Dr Wolf's next book will look at what the digital world is doing to the brain, including looking at brain-scan data as people read both online and in print. She is particularly interested in comprehension results in screen vs print reading.
Researchers say the differences between text and screen reading should be studied more thoroughly and that the differences should be dealt with in education, particularly with school-age children. There are advantages to both ways of reading. There is potential for a bi-literate brain.
"We can't turn back," Dr Wolf said. "We should be simultaneously reading to children from books, giving them print, helping them learn this slower mode and, at the same time, steadily increasing their immersion into the technological, digital age. It's both. We have to ask the question: What do we want to preserve?"