How We Read

“The human eye is capable of focusing on only a very small area at one time – what is called a perceptual span. When we read, we are capable of taking in only about one key word and then four characters to the left and fifteen characters to the right at any one time. We jump from one of these chunks to another, pausing – or fixating – on them long enough to make sense of each letter. The reason we can focus clearly on only that much text is that most of the sensors in our eyes – the receptors that process what we see – are clustered in a small region in the very middle of the retina called the fovea. That’s why we move our eyes when we read: we can’t pick up much information about the shape, or the color, or the structure of words unless we focus our fovea directly on them. Just try, for example, to reread this paragraph by staring straight ahead at the center of the page. It’s impossible.”

-Malcolm Gladwell, The Tipping Point, pg. 108