How We Read
Despite the continuing controversy over the best way to teach reading and over the best time to teach a child to read, a great deal is known and agreed upon about the hidden intricacies of accomplished reading. Reading may seem simple once it has been mastered, but it is amazingly complex. It is dependent on the interaction of many mechanisms which must be coordinated with precise timing. This coordination involves multiple areas of the brain. The evolutionary forces which selected for these mechanisms had their effects long before reading was invented. Areas of the brain which evolved for other purposes must be retrained and coordinated to make reading possible. While one of the functions of vision therapy is to help people develop visual skills whose visual problems make it difficult for them to read, most people learn to read without this intervention. I am more amazed that most people learn to read well than I am that some people have difficulty mastering reading. Complex systems such as reading and sending a rocket into space have multiple vulnerabilities. Prior suggestions that all reading problems have the same cause are as misguided as the assumption that all rocket failures are due to defective O-rings and that only one system can fail at a time.
The visual process of reading is not as it seems. Our eyes do not move smoothly across the page. As with most of what we do, the process of efficient reading is controlled subconsciously and is not available for our conscious inspection. Our eyes make stops (fixations) and jumps (saccades) 4 times a second as we read. We do not take in visual information during saccades although our brain continues to process information. This phenomenon also happens every time we blink and whenever we look from one object to another. Although our visual input is discontinuous, our perception is continuous.
Frequent eye movements are necessary to gather information because we only see a very small area clearly at a time. (see Active Vision) Our eyes move from one area of interest to another area of interest as our brains construct the illusion that we are seeing everything clearly simultaneously. The clarity of our vision decreases sharply as objects are farther from the point of fixation. Only the central 5 degrees has clarity equivalent to 20/20. This correlates with 5 letter spaces. During each fixation which lasts 1/5 of a second, input takes place, new information is processed and combined with what has been read before, our attention shifts to where our eyes will move next, and we predict what the next word will be.
When we think of vision, we think of our focal visual system; the primarily conscious component of our vision which enables us to see clearly, identify what we are seeing, localize it, and to see it in color. The ambient visual system, which works in parallel with the focal system, is primarily subconscious and outside of our voluntary control. It contributes to our balance, helps guide our eye movements, keeps our vision from smearing when our eyes move, and stabilizes our world even when we are moving or objects are moving around us. When this system is poorly developed or poorly integrated, people tend to be unaware that their perception of the world or of the printed page is different from that of others. Dysfunctions of this system become recognizable when the changes are sudden as is caused by head injuries, by excessive movement like spinning in circles, or by the ingestion too much alcohol.
To process what we see efficiently, our eyes must be focused clearly and aligned precisely at each fixation, 4 times a second, and sustained over extended periods of time. If this alignment is off even hundredths of a degree, the information being sent to the brain will have increased ambiguity.
The connection between our eyes and our brain is different than the connections between the rest of our body and our brain. Each eye sends half of its information to each side of the brain. Everything seen to our left is sent to the right cerebral hemisphere by each eye and everything seen to our right is sent to the left cerebral hemisphere by each eye. Efficient readers land 1/3 of the way into a word so more attention is focused on the beginning of the word to facilitate word recognition. It is now recognized that this causes information from the beginning of a word to go to the right hemisphere first while information from the end of the word goes directly to the left hemisphere. The left hemisphere has the primary responsibility for interpreting language. It is not yet understood how this information is recombined in less than 1/5 of a second with information from the end of the word reaching the left hemisphere prior to information from the beginning of the word.
When children start to read, they look at every letter and put the letters together to recognize the word. Not looking at the letters in the proper spatial sequence will make identifying the word more difficult. As the system becomes more efficient, words begin to be processed as single units. Accomplished readers process longer words at almost the same speed that they process shorter words which is known as the word length effect. But if the letters or words are too close together, neighboring letters and words start to interfere as would happen when fine black and white lines are too close together. School books and worksheets are often too crowded which creates more problems for some students than for others. Adults are not immune to this effect. (see Visual Crowding)
The average reading speed for high school students is 250 words per minute which is about 4 words per second or one word per fixation. A reasonable adult reading speed is 350 words per minute which means that we are reading 6 words a second or 6 words for each 4 fixations. We do not read faster by moving our eyes faster. We read faster by taking in more information with each fixation and by reducing the number of errors which are recorded by eye tracking instruments as retrograde saccades. Children start by reading orally and then progress to subvocalizing words as they read. Proficient readers stop subvocalizing most words and recognize the word and the word’s meaning without activating the speech areas of the brain. Persistent subvocalization constrains reading speed.
Over time we develop a sight vocabulary of thousands of words. Words are stored in what is known as the word-form area which develops in the same area of the brain that we use to store information about faces and names. The ability to visualize words enables the development of our sight vocabulary and is essential for successful spelling. When we recognize the shape of the face of someone that we know, a name should be associated with it. Likewise, when we recognize a shape in the form of a word that we know, a name should be associated with it.
What we read is primarily retained in visual images and accessed by recalling those images. As important as language is to our thinking, visual processing and recall develops before language. Visual thinking continues to be important although we may be less aware of when we are using visual processing that we are aware of using language.
When we think of reading and reading problems, we don’t tend to think of these low-level skills, but like many things that we do, it is difficult for our high-level skills to shine if we haven’t developed mastery and automaticity of the prerequisite low-level skills. This is as true of musicians, surgeons, athletes and artists as it is of readers. It should be mentioned that there are also low-level auditory processing skills that have a role in learning to read. As the visual system is sensitive to crowding in space, the auditory system is sensitive to crowding in time. Some people do not process streams of sounds as quickly as do others and coordinating what is seen and what is heard is important in the process of learning to read.
All of this is not to disregard the importance of high-level processing. Working memory is necessary to assimilate current input with what has just been read. Comprehension is dependent on an adequate vocabulary and an information and experience base which enables the reader to relate what we are currently reading to our stored knowledge. Strong language abilities form a rich foundation for reading.
A lot has been said about 10,000 hours being necessary to develop expertise in a complex skill. If a child has been reading daily from the time that they are able to read until they graduate from high school, they will have read over 10,000 hours. Barring complications, a child is expected to be a competent reader long before that time as long as they have been engaged in what they are reading and have not been reading only because they have been forced to read. (see The Talent Code)
For more information see:
Reading in the Brain
Reading in the Brain, Part Two
What if Everybody Understood Child Development? Part 1
Visual word form area in visual cortex remembers words as pictures
It is not a coincidence that recognizing faces and remembering the related name correlates with the ability to learn letters, numerals, and words. They all require vision and language, they all require explicit memory, they all require attention to detail while simultaneously seeing the whole, and they all rely on the ability to automate these functions so they take place accurately, quickly, and subconsciously. Continue reading
Edited by Piers L. Cornelissen and Chris Singleton
From the end of the 19th century until the 1970s, the role of vision in reading and in reading difficulties was considered critical. Starting in the 1970s, many prominent researchers were discounting the importance of vision stating “that dyslexia is caused by a genetically-based anomaly in neurological systems sub-serving phonological processing.” While it is true that auditory skills are important, this took most researchers and educators on a decades long diversion. Continue reading
Learning to read and reading to learn are complex tasks which require many precisely integrated processes to take place rapidly and accurately. Interference with visual input can cause frustration, disinterest, and poor comprehension. Continue reading