A few months back, there was a lot of buzz about a new display technology that promised to greatly increase people's reading speeds. The approach, typified by Spritz, displays words one at a time in a single location. As the speed cranks up and words fly by, the service seems to live up to its promise: each word registers as it briefly flits across the screen.

But a new paper suggests that the approach has some severe limitations. Quite literally, there's no going back once you shoot past a word, and the result is a noticeable decrease in reading comprehension.

At war with saccades

The point of contention for everyone involved centers on small, rapid eye movements called saccades. Saccades occur naturally in vertebrates from us to fish, as they allow the eye to rapidly focus its attention. These eye movements are central to reading. As you read across a page of normally formatted text, your brain directs your eyes through a series of saccades that focus attention on each succeeding word.

The logic behind speed reading techniques is that these saccades are bad. They take time and, perhaps more importantly, they take mental resources to direct the eyes to the right location. This limits the resources available for other processes and leaves our reading prone to distraction as the eyes drift to other locations.

The technique used by Spritz is called rapid serial visual presentation, or RSVP. By always presenting the words in the same location, there is no need for saccades. The eyes don't wander off, and more of the visual system is available for the task at hand: processing words.

Reading vs. comprehension

That's the idea at least. But three psychologists at UC San Diego argue that it's fundamentally misguided. "Control over the sequence and duration of word processing is the most important variable that supports reading," they note. Research suggests that most readers don't tend to saccade fluidly across a page; instead, between 10 and 15 percent of the time, our saccades take us in the wrong direction. Experimental work has suggested that these reversals, technically termed regressions, happen for a reason. Regressions, for example, are much more common in sentences that are prone to misinterpretations.

The authors decided to test whether this was actually the case. To do that, they relied on a high-speed camera directed at the eyes of readers. These cameras fed data into a system that detected when a reader's eyes made a saccade and where their attention was directed. To mimic the consequences of the speed reading method, the software registered when the eyes focused on the next word and converted the previous version to a series of x's.

(You might think that this change would attract people's attention and cause an increased number of backwards saccades. I certainly thought that. But the researchers went through their statistics and found that this wasn't the case. People tended to read as if nothing was amiss.)

The researchers then had the participants read two types of sentences: one where the meaning was unambiguous, and another where the subject of the sentence could only be determined based on words that appeared about two-thirds of the way through the sentence. (An example: “While the man drank the water that was clear and cold overflowed from the toilet.”) Once the sentence was read, they were given a question that determined their comprehension of the sentence.

Even under normal circumstances, comprehension of the ambiguous sentence was below 70 percent. But when previously read words were blocked out, comprehension dropped even further. In contrast, comprehension approached 90 percent for the simpler sentences. Yet even then, it still dropped when words that were read got blocked out.

In fact, eliminating backwards saccades had about the same effect regardless of the sentence's complexity. When the authors checked the participants' eye movements, they found that people are just as likely to move their eyes back to a sentence's subject regardless of how complex the sentence is. In addition, in the cases where none of the words were masked, participants who made these backwards saccades consistently had better comprehension of the sentence than those who hadn't. The worst comprehension scores tended to come from people who tried to look backwards even though the subject of the sentence had been blocked out.

All of this suggests that, although saccades may not make for the most efficient means of ingesting words, they're often critical for the comprehension of sentences. And as the length and complexity of an article or book increases, the number of places where comprehension can go awry grows accordingly. "Removing eye movements from the reading process is precisely the fatal flaw in such speed-reading apps and the reason why they will not be useful for reading any text that is not extremely easy or short," the authors conclude.

That may be overselling the results a bit. Although the large number of trials ensured that all the results were statistically significant, they still relied on only 40 college students. In theory, at least, college students spend a lot of their time trying to extract meaning from textbook sentences, and so they might not reflect the general population that well. It's probably worth extending the analysis to a more diverse population, as well as a group that had experience using something like Spritz for their reading.

But anecdotally, given the large number of times I have to backup and reread a sentence in order to make sure I get key concepts down, the results don't surprise me much at all.

Psychological Science, 2014. DOI: 10.1177/0956797614531148 (About DOIs).