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Why so many artists have lazy eyes, and other things art can teach us about the brain

The views expressed are those of the author and are not necessarily those of Scientific American.


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cave drawing brain art mindNEW YORK—When ancient denizens of central France painted leaping horses on the cave walls at Lascaux, they might not have had the late Renaissance understanding of how to illustrate perspective and three dimensions. But they did, with simple black lines, give the implication of depth, showing the far pair of limbs behind the closer pair.

That seemingly simple detail reveals a world of information about the human brain, concluded various scientists and artists at a World Science Festival panel held June 3 at New York University.

In the world itself, lines do not define objects. "You cannot find objects that have lines around them," rather most people make sense of their surroundings using shapes, color, shading and subtleties of depth, explained Patrick Cavanagh, of the Vision Sciences Lab at Harvard University.

By that measure, line drawings are "not something we’ve evolved to be able to understand," he said, but rather, people in all cultures—and even babies and monkeys—can understand a simple line drawing. The effectiveness of simple line-based representations "wasn’t invented; it was discovered by artists," he noted. Cavanagh called this discovery "a backdoor to the brain," through which scientists can learn more about how the brain makes sense of the visual world: for instance, why we all understand that a straight line that ends at a square’s edge and then continues on the same plane on the other side is probably "behind" the square—and why our brain has so much trouble sorting out even simple optical illusions.

As someone who has worked in pen and ink for decades, cartoonist Jules Feiffer realizes that "what we see is often quite divorced from what is actually there," he noted. He calls the two-dimensional representations metaphors, noting that "the metaphor is often more understandable than the real thing."

And research on the perception of faces reveals that the human brain and individual neurons are tuned to extreme representations, explained Margaret Livingstone, a professor of neurobiology at Harvard Medical School. Her research has shown that people are much quicker to recognize caricatures of people than documentary photographs, showing how the brain at work prizes the representative over the more factual.

After thousands of years of simple line-based drawing—and hundreds of years of more intricate perspective-based art—many researchers and artists alike are now trying to create the experience of three dimensions on a flat page or screen. Although we experience the world as three-dimensional (thanks to the separation of our two eyes, which produce two different vantage point, and the visual cortex, which reassembles the images into a cohesive landscape), recreating that world in art and film has been challenging.

The perplexing task of transforming the two-dimensional depiction into something the brain actually perceives as three-dimensional (à la Avatar) rather than just presuming it (such as prehistoric cave paintings), captured the imagination of Christopher Tyler, who is now director of the Smith Kettlewell Brain Imaging Center. He developed algorithms for patterns of dots that seem to grow off the page into three-dimensional objects even without special glasses (giving birth to the Magic Eye books and posters of the ’90s). Although the pages first appear to be a random splattering of dots, they have been carefully distributed to create what he calls "the attentional shroud" that slowly appears as a three-dimensional shape. With the assistance of classic blue-and-red 3-D glasses, he demonstrated to the audience the complexity of the visual processing system by presenting progressively more difficult images and pointing out the lag time most people experienced before seeing the object—if they could at all.

Generating a moving image in three-dimensions has provided a very different set of problems, explained Buzz Hays, senior vice president of Sony 3D Technology Center. Because humans get a sense of three dimensions by gathering information from each eye and reassembling it in the brain, shooting live action films or television in three dimensions requires two very carefully placed cameras. How far apart the cameras are and where they are angled, however, affect whether an object will appear in front of the screen, on the screen’s plane or behind it—and small changes can make a big difference. If the cameras are too far apart, a scene might have depth of field but objects in it will appear very tiny. And if a director goes amiss trying to create the illusion of infinity, a viewer’s eyes will briefly diverge and go walleyed—a rather painful experience that often isn’t noticed on smaller production monitors, Hays noted.

The advent of three-D movies and TV, however, has left many people squinting in vain. Some 10 percent of all people do not have stereopsis (depth perception), resulting from misalignment of the eyes or focusing trouble, and has trouble seeing depth in three-dimensional movies, art and even, often, physical surroundings. But that seems to come in handy for some professions, noted Harvard’s Livingstone.

About three percent of the general population has misaligned eyes—a condition that can be diagnosed just by looking at photographs of a person, as she demonstrated by showing photos of famous old baseball players with normal eyes and then a picture of the lazy-eyed Babe Ruth. Ruth’s condition was a rarity in professional sports, but the prevalence of lazy eyes, crossed eyes and walleyes, however, seems to be much higher in accomplished artists, her research has shown.

world science festival mind science brain art visionBy examining photographs of artists, Livingstone and her fellow researchers found that Andrew Wyeth, Edward Hopper, Marc Chagall, Jasper Johns, Frank Lloyd Wright, Robert Rauschenberg, Alexander Calder and others all had misaligned eyes. (And by studying the self-portraits and etchings of Rembrandt, she found he also seems to have had a strong lazy eye.) Why this pattern? She proposed that people who have less detailed three-dimensional vision of the world might have an easier time translating what they see onto the two-dimensional page—whether it was for a painting of a diner scene, sketch for a mobile or plan for a building.

Despite the complex and still largely mysterious workings of the visual cortex—and all of the heady research that has gone into trying to understand it—many artists ignore these ideas and others about visual perception when they’re at work. "I’m not thinking when I’m doing it," Feiffer noted, as he sketched a quick pen line drawing of a dancing man for the audience. "There’s no thought process."

Image of Lascaux cave painting courtesy of Wikimedia Commons; image of Marc Chagall, an artist with misaligned eyes, courtesy of Wikimedia Commons





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  1. 1. drollere 5:09 pm 06/4/2010

    ah, academic research. what insights can come from unjustified generalizations.

    i’ve seen a recent study of world leaders that found that adolph hitler, josef stalin, benito mussolini, idi amin, chairman mao, ahmedinejad, hussein and emperor hirohito were all crazy as loons.

    from that, the study authors drew the important insight that being crazy as a loon might allow national leaders to better see the two dimensional aspects of policy, and thereby administer more efficiently.

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  2. 2. billsmith 12:32 am 06/5/2010

    Don’t generalize about generalizations, drollere.

    The generalizations made in the journal article referred to here were merely speculations and an outgrowth of Livingstone and Conway’s other studies. In fact, the title of the article was "Was Rembrandt Stereoblind?" and focused on answering just that question.

    http://www.nytimes.com/2004/09/16/arts/design/16remb.html?pagewanted=2

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  3. 3. DocSalt 2:13 am 06/5/2010

    It seems to me that there is a detail being missed here. They are examining the point that the brain picks up on the spacial representation of depth expressed in 2 dimensional pictures (as the cave drawings) and how amazing it is that people can better identify caricatures than pictures of the actual person. However they fail to point out (unless I missed it?) that these things are the details that a brain picked up on in the first place, and that the artist then tried to convey. The caricature artist is skilled at picking up on the distinguishing features that make a face unique, say the chin size of Jay Leno, the gap tooth grin of David Letterman, the off center lips of Sylvester Stalone (not to mention the jaw line) and over emphasize them to the point the normal scan and process it takes the brain to identify these characteristics is greatly reduced. Often as well there is a comical slant that associates with a strong emotion, be it laughter or anger. Maybe a better examination would be cultivated from drawings by someone with no depth perception and to try and understand the difference in how they interpret what they see and then try to communicate.

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  4. 4. jtdwyer 3:13 am 06/5/2010

    Those who wish to be artists but who unfortunately do not have misaligned eyes can fortunately rely primarily on their dominant eye, or even close one eye! That of course does not provide the artist with the psychological benefit of mistreatment by children and fools.

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  5. 5. mmth 6:51 pm 06/7/2010

    I was born with one eye turned inward and weaker than the other eye. Botched surgery shortened the muscle on the weaker eye too much, making me permanently walleyed. I have had diplopia (double vision) for the last 60 years as a result. I read, watch TV, and use the computer usually with my right eye closed. I’ll never know how inconvenient it is not to have 3-D perspective, since the surgery was done when I was so young. The surgeon mistakenly assumed, no matter how I tried to tell him, that the problem was simply that my right eye was weak; he made me wear a patch on my good eye in order to strengthen the weak one. Doing that was the last thing he should have done, since I can tell which is the "real" image with my strong eye, and suppress the "false" one, which of course is to the left of the true one. If I lost my good eye, though, I would still be able to see out of the bad one well enough to pass a driver’s test, so figuring out which image is the one I should reach for is sometimes difficult when I am tired.

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  6. 6. jgrosay 7:17 pm 06/7/2010

    A recent note in this e-magazine remarked that people that engage in tattooing tend to have more simmetrical two sides of face, and lack of differences between right and left side of face are a marker of good genetical pool. Professor Lopez-Ibor, I believe, former president of world psychiatry society, thinks that artistic production and not fully sane mind many times go along. Erasmus of Rotterdam wrote a "The praise of folly", and Achinas stated that "the number of mad is so high, that prudence must beg their protection". Sanity is so hard to wear, look at GyorgyRevesz’s "Trip around my cranium", that some degree of madness can be considered even a gift. By the way: what or who are the muses?

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  7. 7. suresh10in 6:16 am 06/8/2010

    Brain acts on sensory clues and even slight suggestions trigger off perceptual experiences that cannot be explained entirely based on the sufficiency or nature of the cues provided.The fact is that mind through the brain prosthetic projects itself on to the world through the imagistic representations of the phenomenal world.It has been scientifically validated that such imagistic representations are very crude or rather inaccurate and insufficient representations of the factual world.The so called objective world of reality is highly observer and measurement dependent as quantum mechanically proven.Even the substratum of space and time is ingrained in us tyo ground the sensory experience ,with its influence on logic and intuition ,though it is all relative without any real factual existence devoid of existence.
    Similarly phenomenology can create existence for us through information bits as cues like three dimensional images being created through bits and pieces of a hologram.That is also what Heidegger meant partially through his existential philosophies.The first person and third person self accounts in consciousness literature suggests a disembodied substratum for the more material self.The repudiations of Dennet apart ,the fact remains that a fluid and metaphysical base has been ingrained in us which permits experience based on even the slightest of evidence,defining some sort of qualia ,and brain structures for the same,as per studies in recent literature
    SURESHKUMAR.S,SCIENTIST AND ADVISER,NIIST,TRIVANDRUM,[CSIR]INDIA

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  8. 8. Barbsplace 1:01 pm 06/8/2010

    I found this article most interesting. Having been a professional illustrator for many years, I’ve often wondered how my art was impacted by my lack of depth perception. I have corresponded with Dr. Oliver Sacks, who has done numerous studies of this condition. I believe teachers of young children should be made aware of eye conditions and how they effect students.

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  9. 9. Cerebral*Origami 11:30 am 06/9/2010

    I would also say that a drawing, be it accurate or a characture is a simplification. The artist has removed a great deal of data the brain would have otherwise had to process before object recognition.

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  10. 10. Cerebral*Origami 11:33 am 06/9/2010

    The patch was a seriously bad idea. There exist exersizes (if the mis-alignment is not too severe) to selectivly strengthen eye muscles.

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  11. 11. kwgm 2:41 pm 06/9/2010

    I had an artist friend in college who taught me how to "see". Her methods involve conscious control of certain ocular muscles that relaxed the focus of one or both eyes, increasing the peripheral vision while holding a center focus, mental color replacement (as a computer science student, I thought of this as something like changing portions of the color lookup table), and discovering color, in shadows for instance, that I had never before recognized.

    Without an attempt at banality, her techniques "opened my eyes" or rather my visual mind to a whole new experience of seeing the world around me.

    As a child, do you remember laying back in the grass on a sunny day, looking up and watching the clouds accumulate and roll east as the temperature rose in the early afternoon? I still recall when I first discovered that clouds actually changed shape in these upper level winds, ever so slowly as my imagination free associated this wonder.

    I believe that’s a little of what this "study" is about. Perhaps others have discovered or been coached in the ability to "see" and wonder if this tendency is built-in to our most celebrated artist’s anatomy.

    As for me, I’m happy just playing these games of eyes, the imagination, the beauty of nature and climate, the prevailing pattern of water vaporization in the atmosphere here, or the fascination I derive from creating allegory from "real" life through a simple shift in perspective I get by controlling the tiny muscles around my eyes.

    Aldus Huxley wrote "The Art of Seeing" after his experimentation with so-called psychotropic drugs like mescaline and LSD, but there is no need for medicinal help in watching a passing cloud turn into a flying dragon, or in general, changing one’s vision by changing the way we see the world around us.

    I have no criticism of a scientist’s interest in the alignment of Marc Chagall’s pupils, but personally, I find greater interest in the sight of a glorious sunset over Monument Valley in Navaho country.

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  12. 12. irenealhanati 5:15 pm 03/4/2011

    Yes. I have done these exercises, and got much better. However, I realze now my preference for drawing with simple lines, from my early childhood to the present. I have graduated at THE SCHOOL of Fine Arts, in my hometown, Rio de Janeiro, and love drawing!

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