Certainly, readers are capable of rapidly scanning a text to find a specific word or piece of information, or to pick up a general idea of what the text is about. But this is skimming, not reading. We can definitely skim, and it may be that speed-reading systems help people skim better.

Some speed-reading systems, for example, instruct people to focus only on the beginnings of paragraphs and chapters. This is probably a good skimming strategy. Participants in a 2009 experiment read essays that had half the words covered up — either the beginning of the essay, the end of the essay, or the beginning or end of each individual paragraph. Reading half-paragraphs led to better performance on a test of memory for the passage’s meaning than did reading only the first or second half of the text, and it worked as well as skimming under time pressure.

But speed reading? Techniques that aim to guide eye movements so that we can take in more information from each glance seem doomed to fail. There is only a small area in the retina (called the fovea) for which our visual acuity is very high. Our eyes are seriously limited in their precision outside of that. This means that we can take in only a word or so at each glance, as well as a little bit about the words on either side. In fact, since the 1960s, experiments have repeatedly confirmed that when people “speed read,” they simply do not comprehend the parts of the text that their eyes skip over.

A deeper problem, however — and the one that also threatens the new speed-reading apps — is that the big bottleneck in reading isn’t perception (seeing the words) but language processing (assembling strings of words into meanings). Have you ever tried listening to an audio recording with the speaking rate dialed way up? Doubling the speed, in our experience, leaves individual words perfectly identifiable — but makes it just about impossible to follow the meaning. The same phenomenon occurs with written text.

As in all forms of human behavior, there is a trade-off, in reading, between speed and accuracy. You can learn to skim strategically so that you spend more time looking where the more important words are likely to be, and if the words are presented in a stream you may be able to learn which words to focus on and which to ignore. However, that does not mean that you can somehow magically read parts of a page that you don’t look at, or process all the words in a superfast sequence.