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Scientists are prone to going on and on about how strikingly early in life we are able to comprehend speech. Our children’s aptitude for reading, however, doesn’t cause much excitement. At first glance this seems sensible: children comprehend speech fairly well by two, whereas they typically can’t read until about five. This is because, the standard story goes, we evolved to comprehend speech but did not evolve to read. And while one might debate whether we have evolved to comprehend speech, no one believes we evolved to read. Writing is only several thousand years old, far too short a time to have crafted reading mechanisms in our brain. And for many of us, our ancestors only started reading one or several generations back.

But are children really so clunky at learning to read? At five years old, most children can’t be trusted to pour a pint of beer without spilling it, and most can’t even do stereotypical ape behaviors like somersaults and the monkey bars. And yet these same wee ones are reading. That’s quite an accomplishment for an ape, especially one who gets read to so infrequently compared to getting talked to.

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Children are, in fact, quick learners of reading, and our brains become fantastically capable readers. How can we come to be so good at reading if we don’t have a brain for it? Is it because our visual system can handle any writing one may throw at it? No. Our children would be hopeless if writing looked like bar codes or fractal patterns. How, then, did apes like us come to read?

Gifted neuroscientist Stanislas Dehaene argues in his new book, Reading in the Brain (Viking), that we read not because we have a reading instinct, and also not because our visual brain is a particularly pliable learner. Rather, we read because culture “neuronally recycles” our visual system. Culture over time has seen to it that the letter shapes of our writing systems have the shapes our visual system is good at processing. In particular, the brain is competent at processing the contour combinations that occur in natural scenes, and writing systems have come to disproportionately use these shapes.

For example, below are four configurations each having three contours and two Ts. Three of the four can happen in natural scenes, but one of these cannot, and it turns out that only this oddball is rare across human writing systems. It is not so much that the brain has a reading instinct, but that writing has a brain instinct. In fact, to the extent that writing has come to be shaped like nature (in order to get into the brain), writing has a nature instinct.

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More generally, Dehaene’s line of thinking suggests that much of what makes humans stand so far apart from the other apes is a result of neuronal recyclling – not a result of natural selection at all.

Other pieces about the origins of writing are here, and also play prominently in my book, The Vision Revolution.

This first appeared on January 12, 2010, as a feature at the Telegraph.

Mark Changizi is a professor of cognitive science at Rensselaer Polytechnic Institute, and the author of The Vision Revolution (Benbella Books).

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This is the Wall Street Journal review of The Vision Revolution that appeared earlier this year.

Why the Eyes Have It
We can read words, gauge distance and see color. How did that happen?

By Christopher F. Chabris

Why are we ­humans so good at seeing in color? Why do we have eyes on the front of our heads rather than on the sides, like horses? And how is it that we find it so easy to read when written language didn’t even exist until a few thousand years ago—a virtual millisecond in evolutionary time?

Details

The Vision Revolution

By Mark Changizi

Ben Bella, 215 pages, $24.95

Read an excerpt of “The Vision Revolution”

Most of us, understandably, have never given much thought to questions like these. What is surprising is that most cognitive scientists ­haven’t either. People who study the brain generally ask how it works the way it does, not why. But Mark Changizi, a professor at Rensselaer ­Polytechnic Institute and the author of “The Vision ­Revolution,” is indeed a man who asks why, and lucky for us: His ideas about the brain and mind are fascinating, and his explanations for our habits of seeing are, for the most part, persuasive.

Mr. Changizi takes care not to call himself a practitioner of evolutionary psychology. This is the one discipline of the mind sciences that focuses on why questions, but it often answers them by telling just-so stories that cannot be ­disproved. (Why do men have better spatial ability than women? Because a long time ago, in Africa, men needed spatial skills to track prey and to kill at a distance—a plausible theory but one that is difficult to test with experiments.) Instead Mr. Changizi calls ­himself a “theoretical neuroscientist,” seeking explanations for the design of the mind that are based on mathematical and physical analysis. He has his own stories, it is true, but they are grounded solidly in neuroscience, and they are backed up by data about a surprising range of human activities, from ­the colors found in historical ­costumes to the ­correspondence between the shapes found in written letters and the shapes found in ­nature.

Let’s start with the question of color. It is such a natural part of our visual experience that we don’t stop to wonder why we can see it at all. ­Without color television there would have been no “Miami Vice,” of course, but were we really missing out on so much when we had only black and white? The consensus explanation for our superior ability to perceive color is that primates evolved it to see fruit—you can’t order dinner if you can’t read the menu.

Mr. Changizi thinks otherwise. He proposes that color vision is useful for distinguishing the changes in other ­people’s skin color—changes that are caused by shifts in the volume and oxygenation levels of the blood. Such shifts, like blushing, often signal emotional states. The ability to see them is adaptive because it helps an observer to “read” states of mind and states of health in others, information that is in turn useful for predicting their behavior.

Our brains evolved in a time when people lived their entire lives without ever seeing someone with a skin color different from their own. Thus the skin color we grow up seeing, Mr. Changizi says, is “neutral” to us: It serves as a kind of baseline from which we notice even minor deviations in tint or hue. Almost every language has distinct words for some 11 basic colors, but none of them aptly describe the look of skin, which seems colorless (except in our recent multicultural societies, where skin color is newly prominent). As one might expect, primates without color vision tend to have furry faces and hands and thus less need to perceive skin color; ­primates with color vision are more “naked” in this respect, humans most of all.

James Steinberg

Conventional wisdom may be similarly misleading when it comes to binocular vision. It is said that we have two forward-facing eyes, which send our brains two separate images of almost everything in our field of view so that the brain can compare those images to estimate the distance of objects—a generally useful thing to know. But people who are blind in one eye, Mr. Changizi notes, can perform tasks like driving a car by using other cues that help them to judge distance. He offers a different explanation: that two eyes give us a sort of X-ray vision, allowing us to see “through” nearby objects to what is beyond.

You can experience this ability yourself by closing one eye and holding your forefinger near your face: It will appear in your field of vision, of course, and it will block what lies beyond or behind it. If you open both eyes, though, you will suddenly perceive your finger as transparent—that is, you will see it and see, ­unblocked, the full scene in front of you. Mr. Changizi observes that an animal in a leafy environment, with such an ability, gains an advantage: It can lurk in tall grass and still see what is “outside” its hiding place. He correlates the distance between the eyes and the density of vegetation in the habitats of animals and finds that animals with closer-set eyes do tend to live in ­forests rather than on plains.

As for reading, Mr. Changizi stops to observe how remarkable this ability is and how useful, giving us access to the minds of dead people (i.e., deceased writers) and permitting us to take in words much faster than we can by merely listening to them. He claims that we learn to read so easily because the symbols in our written alphabets have evolved, over many generations, to resemble the building blocks of natural scenes—­exactly what previous millennia of evolution adapted the brain to perceive quickly. A “T,” for example, appears in nature when one object overlaps ­another, like a stone lying on top of a stick. With statistical analysis, Mr. Changizi finds that the contour patterns most common in nature are also most common in letter shapes.

Mr. Changizi has more to say about our visual experience—about optical illusions, for instance, which he sees as artifacts of a trick the brain uses to cope with the one-tenth of a second it takes to process the light that hits our eyes and to determine what is actually in front of us. He calls for a new academic discipline of “visual linguistics,” and he tells us why there are no ­species with just one eye.

What does all this add up to? Provocative hypotheses but not settled truth—at least not yet. As a theoretician, Mr. Changizi leaves it to others to design experiments that might render a decisive ­verdict. Someone else will have to study how accurately people can perceive mental states from shifting skin tones, and someone else will have to ­determine whether, in most cases, looking at another ­person’s skin adds any useful information to what is easily known from facial expression, tone of voice and body ­language.

Still, the novel ideas that Mr. Changizi outlines in “The Vision Revolution”—together with the evidence he does present—may have a big effect on our understanding of the human brain. Their implication is that the environments we evolved in shaped the design of our visual system according to a set of deep principles. Our challenge now is to see them clearly.

Mr. Chabris is a psychology professor at Union College in Schenectady, N.Y.
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Mark Changizi is Professor of Cognitive Science at RPI, and the author of The Vision Revolution (Benbella, 2009) and The Brain from 25000 Feet (Kluwer, 2003).

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(BOOK EXCERPT, Wall Street Journal ; WSJ review here)

The Vision Revolution’ (Benbella Books, 2009)

By Mark Changizi

Introduction

Super-Naturally

In the movie “Unbreakable” by M. Night Shyamalan, the villain Elijah Price says, “It’s hard for many people to believe that there are extraordinary things inside themselves, as well as others.” Indeed, the story’s superhero, David Dunn, is unaware of his super strength, his inability to be injured (except by drowning), and his ability to sense evil. Dunn would have lived his life without anyone—including himself—realizing he had superpowers if Unbreakable’s villain hadn’t forced him into the discovery.

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At first glance we are surprised that Dunn could be so in the dark about his abilities. How could he utilize his evil-detection power every day at work as a security guard without realizing he had it? However, aren’t most powers—super or otherwise—like that? For example, our ability to simply stand requires complex computations about which we are unaware. Complex machines like David Dunn and ourselves only function because we have a tremendous number of “powers” working in concert, but we can only be conscious of a few of these powers at a time. Natural selection has seen to it that precious consciousness is devoted where it’s most needed—and least harmful—leaving everything else running unnoticed just under the surface.

The involuntary functions of our bodies rarely announce their specific purposes. Livers never told anyone they’re for detoxification, and they don’t come with user’s manuals. Neurosurgeons have yet to find any piece of brain with a label reading, “Crucial for future-seeing. Do not remove without medical or clerical consultation.” The functions of our body are carried out by unlabeled meat, and no gadget—no matter how fancy—can allow us to simply read off those functions in a lab.

Powers are even harder to pin down, however, because they typically work superbly only when we’re using them where and when we’re supposed to. Our abilities evolved over millions of years to help us survive and reproduce in nature, and so you can’t understand them without understanding the environment they evolved for, any more than you can understand a stapler without knowing what paper is.

Superpowers, then, can’t be introspected. They can’t be seen with a microscope. And they can’t be grasped simply by knowing the ins and outs of the meat. Instead, the natural environment is half the story. Lucky for us there are ways of finding our powers. Science lets us generate a hypothesis concerning the purpose of some biological structure—what its power is—and then test that hypothesis and its predictions. Those predictions might concern how the power would vary with habitat, what other characteristics an animal with that power would be expected to have, or even what that biological structure would look like were it really designed with that power in mind. That’s how we scientists identify structures’ powers.

And that’s what this scientist is doing in this book: identifying powers. Specifically, superpowers. Even more specifically, superpowers of vision—four of them, one from each of the main subdisciplines of vision: color, binocularity, motion, and object recognition. Or in superhero terms: telepathy, X-ray vision, future-seeing, and spirit-reading. Now, you might be thinking, “How could we possibly have such powers? Mustn’t this author be crazy to suggest such a thing?” Let me immediately allay your fears: there’s nothing spooky going on in this book. I’m claiming we have these four superpowers, yes, but also that they are carried out by our real bodies and brains, with no mysterious mechanisms, no magic, and no funny business. Trust me—I’m a square, stick-in-the-mud, pencil-necked scientist who gets annoyed when one of the cable science channels puts a show on about “hauntings,” “mystics,” or other nonsense.

But then why am I writing about superpowers? “No magic, no superpowers,” some might say. Well, perhaps. But I’m more inclined to say, “No magic, but still superpowers.” I call each of these four powers “superpowers” because each of them has been attributed to superhuman characters, and each of them has been presumed to be well beyond the limits of us regular folk.

That we have superpowers of vision—and yet no one has realized it—is one of the reasons I think you’ll enjoy this book. Superpowers are fun, after all. There’s no denying it. But superpowers are just a part of this book’s story. Each of the four superpowers is the tip of an iceberg, and lying below the surface is a fundamental question concerning our nature. This book is really about answering “why”: Why do we see in color? Why do our eyes face forward? Why do we see illusions? Why are letters shaped the way they are?

What on Earth is the connection between these four deep scientific questions and the four superpowers? I’d hate to give away all the answers now—that’s what the rest of the book is for—but here are some teasers. We use color vision to see skin, so we can sense the emotions and states of our friends and enemies (telepathy). Our eyes face forward so that we can see through objects, whether ourown noses or clutter in the world around us (X-ray vision). We see illusions because our brain is attempting to see the future in order to properly perceive the present (future-seeing). And, lastly,letters have culturally evolved over centuries into shapes that look like things in nature because nature is what we have evolved to be good at seeing. These letters then allow us to effortlessly read the thoughts of the living . . . and the dead (spirit-reading).

Although the stories behind these superpowers concern vision, they are more generally about the brain and its evolution. Half of your brain is specialized for performing the computations needed for visual perception, and so you can’t study the brain without spending about half your energies on vision; you won’t miss out on nearly as much by skipping over audition and olfaction. And not only is our brain “half visual,” but our visual system is by far the most well-understood part of our brains. For a century, vision researchers in an area called visual psychophysics have been charting the relationship between the stimuli in front of the eye and the resultant perception elicited “behind” them, in the brain. For decades neuroanatomists such as John Allman, Jon Kaas, and David Van Essen have been mapping the visual areas of the primate brain, and countless other researchers have been characterizing the functional specializations and mechanisms within these areas.

Furthermore, understanding the “why” of the brain requires understanding our brain’s evolution and the natural ecological conditions that prevailed during evolution, and these, too, are much better understood for vision than for our other senses and cognitive and behavioral attributes. Although about half the brain may be used for vision, much more than half of the best understood parts of the brain involve vision, making vision part and parcel of any worthwhile attempt to understand the brain.

And who am I, in addition to being a square, stick-in-the-mud, pencil-necked cable viewer? I’m a theoretical neuroscientist, meaning I use my training in physics and mathematics to put forth and test novel theories within neuroscience. But more specifically, I am interested in addressing the function and design of the brain, body, behaviors, and perceptions. What I find exciting about biology and neuroscience is why things are the way they are, not how they actually work. If you describe to me the brain mechanisms underlying our perception of color, I’ll still be left with what I take to be the most important issue: Why did we evolve mechanisms that implement that kind of perception in the first place? That question gets at the ultimate reasons for why we are as we are, rather than the proximate mechanical reasons (which make my eyes glaze over). In attempting to answer such “why” questions I have also had to study evolution, for only by understanding it and the ecological conditions wherein the trait (e.g., color vision) evolved can one come to an ultimate answer. So I suppose that makes me an evolutionary theoretical neuroscientist. That’s why this book is not only about four novel ideas in vision science, but puts an emphasis on the “evolution” in “revolution.”

Excerpted with permission of the publisher, BenBella Books, Inc. All rights reserved.

Mark Changizi is Professor of Cognitive Science at RPI, and the author of The Vision Revolution (Benbella, 2009) and The Brain from 25000 Feet (Kluwer, 2003).

[Some related pieces in ScienceDaily: visual computer, “x-ray” vision, color empath, letter shaped like nature, illusions of future]

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Working now on my third book, called HARNESSED: How Language and Music Mimicked Nature and Transformed Ape to Man. Here is the short overview…

If one of our non-speaking ancestors were found frozen in a glacier and revived, we imagine that he would find our world jarringly alien. The concrete, the cars, the clothes, the constant jabbering – it’s enough to make a hominid jump into the nearest freezer and hope to be reawoken after the apocalypse. But would modernity really seem so frightening to our guest? Although cities and savannas would appear to have little in common, might there be deep similarities? Could civilization have retained vestiges of nature, easing our ancestor’s transition?

Although we were born into civilization rather than thawed into it, from an evolutionary point of view we’re an uncivilized beast dropped into cultured society. We prefer nature as much as the next hominid, in the sense that our brains work best when their computationally sophisticated mechanisms can be applied as evolutionarily intended. One might, then, expect that civilization will have been shaped over time to possess signature features of nature, thereby squeezing every drop of evolution’s genius for use in the modern world.

Does civilization mimic nature? In his new book, HARNESSED, Mark Changizi argues that the most fundamental pillars of humankind are thoroughly infused with signs of the ancestral world. Those pillars are language and music. Cultural evolution over time has led to language and music designed as a simulacra of nature, so that they can be nearly effortlessly utilized by our ancient brains. Languages have evolved so that words look like natural objects when written and sound like natural events when spoken. And music has come to have the signature auditory patterns of people moving in one’s midst.

But if the key to our human specialness rests upon powers likely found in our non-linguistic hominid ancestors, then it suggests we are our non-linguistic hominid ancestors. Our thawed ancestors may do just fine here because our language would harness their brain as well. Rather than jumping into a freezer, our long-lost relative may choose instead to enter engineering school and invent the next generation of refrigerator. The origins of language and music may be attributable not to brains having evolved language or music instincts, but, rather, to language and music having culturally evolved brain instincts. Language and music shaped themselves over many thousands of years to be tailored for our brains, and because our brains were cut for nature, language and music mimicked nature. …transforming ape to man.

Mark Changizi is Professor of Cognitive Science at RPI, and the author of The Vision Revolution (Benbella, 2009) and The Brain from 25000 Feet (Kluwer, 2003).

[See related pieces on music in ScienceDaily and Scientific American.]

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