The Eyes of a Reader

The application of reading skill in eye exams where we’re asked “How many letters can you see in the bottom row?” works in a peculiarly sociocultural, scientific way. Think about it. If you were designing a way to measure and express variations in quality of visual acuity—how clearly one can perceive and identify an object from a certain distance—how would you go about it? Would you go to a football field with your golden retriever, chain it to a goal post, and have your subjects report whether they can make out the creature from the 20 yard line, then back them up to the 25 yard line if they could make out Rover, then the 30 yard line and so on? Why or why not? [25 pts.]

Human beings have always had problems with seeing things clearly, prompting thinkers to invent aids for vision long ago in early history. The Ancient Greeks had vision aids, probably not really good ones, and their philosophers were not silent on the topic. The goddess Theia, a primal goddess said to be the eldest daughter of Gaia (Earth) and Uranus (Sky), came to be known as the goddess of glitter and a source of human vision:

“Mother of the Sun, Theia of many names, for your sake men honor gold as more powerful than anything else; and through the value you bestow on them, O queen, ships contending on the sea and yoked teams of horses in swift-whirling contests become marvels.” (Pindar)

Glasses as we know them today were invented in Italy around 1286, crude though they were. Advances came relatively quickly in Earth years. Two centuries later, lens grinders learned to make concave and convex lenses and sold to customers. Four more centuries later, the field of optometry had advanced enough that eye doctors realized that people with vision problems do not all have the same problem, but there are common types of problems.

In 1862, Hermann Snellen developed the Snellen Eye Chart, the one optometrists everywhere still use. This tool helps eye doctors determine how well a patient can see objects twenty feet away compared to the average human eye. Snellen was a colleague of Dr. Francisco Donders, who asked his clients to look at a chart on a wall that wasn’t such a good chart and say what they could see. To increase accuracy, Donders asked Snellen to create a new chart.

First, Snellen tried using abstract images and symbols; but the patient who could “see” the symbol may not understand its meaning and so could not say what it was as proof of “seeing” the object. So Snellen used a grid using letters and numbers, which he called “optotypes.” Ultimately, he invented the chart we use today, providing a standard which gradually became part of common practice. He also created the “tumbling E” chart for illiterates and young children.

Thoughts about an optic nerve carrying signals from the eye to the brain stretched back to Ancient Greece. Remarkable advances in understanding the optic nerve as a part of a neurological electric circuit in the 18th century informed Snellen, a Dutch scientist working in a line of Nordic scientists uncovering facts of vision. Antonie van Leeuwenhoek, known as the father of the microscope, was a self-taught scientist who parlayed his interest in lens making into a new field of study, microscopy, and taught us to “see” objects like bacteria, protozoa, red blood cells, spermatozoa, and nerves, including the optic nerve.

The secret to making a microscope turned out to be the secret of telescopes as well, giving us new eyes to see spaces and places hidden in the mists of reality. Convex lenses, bulge outwards in the center and bend parallel light rays entering the lens to converge (come together) at a focal point; they are used in magnifying glasses, cameras, telescopes, and eyeglasses for farsighted individuals. Concave lenses curve inward at the center like a cave and make parallel light rays spread out (diverge) away from each other. Examples include peepholes in doors, flashlights, and eyeglasses for nearsighted individuals. Telescopes involve complex combinations of mirrors, convex, and concave lenses.

Edmond Huey (1908)¹, among the first pioneers in the study of reading, was the first influential reading scientist to speculate about the role of the eyes in reading. Whereas Snelling’s interest in letters was purely expedient—he needed an object to replace the symbols he experimented with in earlier versions of his eye chart, an object that could be identified without meaning attached to it—Huey’s interest was theoretical. Recognizing letters as objects was important, but how the mind’s eye finds meaning in these objects in words took up the focus of his attention.

In 1908 he speculated, for example, that reading speed is increased when readers fixate on the upper half of lower-case letters because distinctive features of letters reside in this space. This speculation still draws attention from reading researchers. In the 1920s Huey developed one of the first eye-tracking devices, which involved a contact lens with an aluminum pointer that moved in conjunction with the eye. With knowledge of the work of Emile Javal, Huey was interested in understanding more deeply how the eyes were regulated during the act of reading.

Javal had contributed technical vocabulary describing the kinds of movements eyes make to perceive any object. In the late 19th century he reported that the eyes do not move continuously whether they are looking at a bakery’s goods or along a line of text. Instead, they make rapid jerky movements (saccades) followed by stops (fixations). We see nothing during the saccade, everything during the fixation. His findings were supported by naked-eye observations, but in the 1920s and 30s, Guy Thomas Buswell, a reading researcher with considerable influence, extended Javal’s inquiry. Buswell understood Javal’s ideas on how the eyes move during reading; he wanted to know what the conditions were that made them move. He created photographic methods to record eye movements on film and correlate them with alphabetic information in the text.

In the 1920s Buswell published findings that are still accepted today. The following photo depicts a paragraph from Rayner and Pollatsek (1989) which reports some of the most important insights Buswell provided us:

Note that Schnell’s eye chart came about in an effort to assess visual acuity at fixation without regard for meaning. If meaningful symbols (a sketch of a chocolate eclair, for example) would have served his purposes, he would never have moved on to try letters. Letters in themselves usually have no meaning, but the majority of patients seeing an eye doctor would know them.

Reading researchers attended to issues of visual acuity at fixation with meaning activation using eye-movement photography. In other words, those who study reading aren’t concerned with prescribing eye glasses. They are concerned instead with the relationship between cognitive activity as it functions during comprehension and visual word perception in running text—how long does it take to perceive strings of letters and convert them into meaning during acts of reading? The eye-voice span, for example—the fact that the eyes perceive words more quickly than the mouth can speak—allows us to assert that silent reading is more efficient than oral reading, though it doesn’t mean that the sounds of words are irrelevant.

Buswell pursued eye-movement research on adult readers as well as children, offering insights into developmental patterns. His interest extended to questions about how the eyes work during perception of pictures, contributing to the wider study of visual cognition. His most famous studies came in a quick pair: “An Experimental Study of the Eye-Voice Span” (1920), where he discovered that when reading is going well the eye processes information well in advance of the voice; the second was “Reading as a Visual Task” (1921), where he theorized about the role of vision in reading to inform the creation of reading materials for educational use—fonts, font size, and the like.

Chapter three in Rayner and Pollatsek’s book discusses important findings from decades of eye-movement research, the bulk of which remains uncontested as far as I know (please comment if you have better knowledge). A central question at the heart of the Reading Wars we hear about from time to time is this: Does context make a difference in word recognition? Or are words perceived the same way in isolation as they are in context? These researchers summarized the state of the art in eye-movement studies as follows:

By “automatic (1),” these writers mean that word recognition is unconscious and effortless. In fact, it’s difficult NOT to perceive a word when is presented. Try it. Conversion to sound (2) is important not because it helps identify a word—mature readers do not often sound out words, though we currently tend to teach beginning readers mandating a phonic conversion. Instead, word acoustics are important for selected words after they are recognized. Holding an acoustic image in auditory short-term memory helps with comprehension.

This generalization is important for an understanding of dyslexia. Readers classified as dyslexic do not have visual perception problems, for example, they don’t perceive letters or words in reverse or swimming around. Mainstream research literature is confident that transforming visual words to spoken words occurs during text reconstruction, not during word identification, when short-term memory stores a word acoustically as a base long enough for subsequent processing to create larger portions of textual meaning: Flat…late…appointment. But sounding out a word in isolation calls on short-term memory to recall abstract, meaningless phonemes: b…oo…k…t. In this case, sounds can float or drop out: oo…b…kt…. Learners with short-term auditory memory for abstract sounds whether in word production or reception are considered dyslexic depending on other factors, an inexact but flourishing science for sure.

Serial processing vs. parallel processing (3) means that letter strings are perceived as wholes during a fixation. Whether the letter string activates sounds or taps directly into meaning, competent readers process them in parallel, not one at a time, no more than we process spoken words one sound at a time. Differences between word processing in isolation vs the same word in context (4) are minimal—and the same is true of spoken words. Barbecue. Let’s have a barbecue.

There is no appreciable difference in identifying the word in or out of context, though the word in context requires post-lexical access processing to integrate its meaning into a message. But notice: Yolk. If we call something that’s funny a joke, we must call the white of an egg a _____. Perhaps the most important takeaway from eye-movement research for adult readers of Substack is this: We know from eye-movement studies that humans cannot read 2,000 words per minute. Silent reading speed is about double the speed of speech (around 300-350 words per minute silently). Any faster doesn't qualify as a fulsome reading. Editorial comment: Most of us read too fast, not too slowly,a hazard when a text is complex.

I’ve only scratched the surface of the eyes of readers. There is much more to this topic than I can discuss in this post. Knowing about saccades and fixations, eye-movement studies, identifying words in isolation vs. in context—these are rudiments that can carry you a nice little distance in creating a substantive understanding and may have piqued your interest in discussion. Current eye-tracking technology is very sophisticated, making it possible to collect eye-movement data with portable devices classroom teachers can use. Also, applications have expanded to include psychology, marketing, human-computer interaction, and even sports performance. If you have any specific questions or concerns or knowledge related to what I’ve written or have not addressed, please raise them in the comments.

1. Much of the discussion that follows leans on the work of Keith Rayner and Alexander Pollatsek (1989), The Psychology of Reading. I used this text in graduate classes early in my university teaching and recommend checking it out at a university library to anyone with a serious interest in reading as a visual process. Without a doubt the period since this book was published has refined and expanded knowledge of this topic; as far as I can tell, little has changed in terms of the rudiments of theory.