Does reading faster mean reading better? That’s what speed-reading apps claim, promising to boost not just the number of words you read per minute, but also how well you understand a text. There’s just one problem: The same thing that speeds up reading actually gets in the way of comprehension, according to a new study. When you read at your natural pace, your eyes move back and forth across a sentence, rather than plowing straight through to the end. Apps like Spritz  or the aptly named Speed Read  are built around the idea that these eye movements, called saccades, are a redundant waste of time. It’s more efficient, their designers claim, to present words one at a time in a fixed spot on a screen, discouraging saccades and helping you get through a text more quickly. This method, called rapid serial visual presentation (RSVP), has been controversial since the 1980s, when tests showed it impaired comprehension, though researchers weren’t quite sure why. With a new crop of speed-reading products on the market, psychologists decided to dig a bit more and uncovered a simple explanation for RSVP’s flaw: Every so often, we need to scan backward and reread for a better grasp of the material. Researchers demonstrated that need by presenting 40 college students with ambiguous, unpunctuated sentences ("While the man drank the water that was clear and cold overflowed from the toilet”) while following their subjects’ gaze with an eye-tracking camera. Half the time, the team crossed out words participants had already read, preventing them from rereading (“xxxxx xxx xxx drank the water …”). Following up with basic yes-no questions about each sentence’s content, they found that comprehension dropped by about 25% in trials that blocked rereading versus those that didn’t , the researchers report online this month in Psychological Science. Crucially, the drop was about the same when subjects could, but simply hadn’t, reread parts of a sentence. Nor did the results differ much when using ambiguous sentences or their less confusing counterparts (“While the man slept the water …”). Turns out rereading isn’t a waste of time—it’s essential for understanding.
See more ScienceShots .