Although many old and recent studies conclude that people understand what they read on paper more thoroughly than what they read on screens, the differences are often small. Some experiments, however, suggest that researchers should look not just at immediate reading comprehension, but also at long-term memory.

When taking the quiz, volunteers who had read study material on a monitor relied much more on remembering than on knowing, whereas students who read on paper depended equally on remembering and knowing.

E-ink is easy on the eyes because it reflects ambient light just like a paper book, but computer screens, smartphones and tablets like the iPad shine light directly into people's faces.

the American Optometric Association officially recognizes computer vision syndrome.

People who took the test on a computer scored lower and reported higher levels of stress and tiredness than people who completed it on paper.

Although people in both groups performed equally well on the READ test, those who had to scroll through the continuous text did not do as well on the attention and working-memory tests.

Subconsciously, many people may think of reading on a computer or tablet as a less serious affair than reading on paper. Based on a detailed 2005 survey of 113 people in northern California, Ziming Liu of San Jose State University concluded that people reading on screens take a lot of shortcuts—they spend more time browsing, scanning and hunting for keywords compared with people reading on paper, and are more likely to read a document once, and only once.

When reading on screens, people seem less inclined to engage in what psychologists call metacognitive learning regulation—strategies such as setting specific goals, rereading difficult sections and checking how much one has understood along the way

Perhaps she and her peers will grow up without the subtle bias against screens that seems to lurk in the minds of older generations.

They think of using an e-book, not owning an e-book,"

Participants in her studies say that when they really like an electronic book, they go out and get the paper version.

When it comes to intensively reading long pieces of plain text, paper and ink may still have the advantage. But text is not the only way to read.