Leonardo's Brain

by Leonard Shlain

  In the thousands of years preceding Leonardo, beginning with the cave paintings of southern France and continuing on into the distinctive styles of art created in ancient Egypt, Mesopotamia, Harrapa (Indus Valley, India), Classical Greece and Rome, Mesoamerica, Medieval Europe, and the High Middle Ages, the background was never the sole subject of a work of art. Previously, human figures, their godlike avatars, or animals dominated the focus. Artists often treated the background as if it was, well . . . background.

  In contrast, Eastern artists had made the elements of nature and their harmonious relationships the predominant subject of Asian art. In practically all of their major landscape scenes, an identifiable human element is present—small and insignificant, to be sure, but nearly always discernible in some part of the composition. The artist reminds the viewer of the insignificance of man compared to the majesty of nature. Generally, the Western artist adopted the exact opposite position: The focus was on the figures in the foreground—until Leonardo.

  No identifiable human exists in Leonardo’s 1473 drawing of Val d’Arno. Although there are some tiny man-made dwellings barely visible far in the distance, it does not appear that he intended to make a statement similar to the kind for which Eastern artists strove. Leonardo simply desired to make nature, not humankind, the subject of his composition. This hastily drawn but elegantly executed landscape is the beginning of the flood of landscape paintings destined to grace the walls of numerous hotel rooms, school hallways, museum walls, and collectors’ dens in the succeeding centuries.

  Half a century later, the German painter Albrecht Altdorfer painted in oils the first Western landscape completely devoid of any animal, human, or supernatural personage (Danube Landscape near Regensburg, 1522–25). Art historians generally honor Altdorfer with the pride of primacy as the first Western landscape artist. It is not known whether or not Leonardo’s earlier work had any influence on Altdorfer. If art historians tabulate the enormous number of landscapes painted since Leonardo’s pen-and-ink drawing, and the total absence in Western art of this genre before his sketch, it seems reasonable that they would accord a special honor to his work located at a critical hinge point in art history.

  Leonardo’s sketch is all the more impressive when one considers that the three monotheistic Western religions, Judaism, Christianity, and Islam, had a very contentious relationship with depictions of nature. They had supplanted earlier “pagan” religions, each of which worshipped nature and venerated sensuality, fertility, and sexuality. Abrahamic religions, in contrast, worshipped an incorporeal deity who occupied an ethereal realm existing above and outside of nature. These religions believed their deity was the creator of nature rather than viewing nature as a manifestation of deity, which was the core of all earlier systems of belief. The three Western religions, firmly rooted in the written word, denigrated nature because the so-called “pagan” beliefs competed with the newer, monotheistic doctrines. Early adherents banished flowers and plants from the interior of any synagogues, churches, or mosques.

  It is not a coincidence that the second commandment, the second most important rule of righteous living, proscribes the making of images—and not just graven images, but images of anything:

  Lest ye corrupt yourselves, and make you a graven image, the similitude of any figure, the likeness of male or female, the likeness of any beast that is on the earth, the likeness of any winged fowl that flieth in the air, the likeness of any thing that creepeth on the ground, the likeness of any fish that is in the waters beneath the earth. (Deuteronomy 4:16–18)

  Authorities representing the principal Western religions considered any likeness created by the human hand depicting any aspect of nature an “abomination,” because it could possibly detract from the worship of an invisible deity. “Thou shalt make no images” is the gist of the Second Commandment, and “Thou shalt not kill” is the sixth. Question: Why did the West’s three major religions all rank art more dangerous than murder?

  Following the fall of the Western Roman Empire in the fifth century AD, and for the next four hundred years—sometimes referred to as the Dark Ages—the approximate literacy rate of Western Europe fell to 1 percent. This, then, was the quandary: If the population remained essentially illiterate, by what means could the ecclesiastical class inculcate the tenets of the struggling Christian religion?

  Pope Saint Gregory the Great (590–604) effectively annulled the Old Testament’s Second Commandment, but insisted that the Church—the primary dispenser of commissions—play the leading role in censoring what exactly the artists chose as proper subjects for their art. In the midst of the heavy religiosity that still characterized much of the Renaissance, it took a mold-breaking sensibility for an artist to focus on the pleasing arrangement of rocks, hills, trees, and distant vistas. And, Leonardo drew it in flawless perspective.

  The signature breakthrough in Renaissance art was the artists’ discovery of perspective. It allowed them for the first time to place the objects in their increasingly complex compositions in an orderly hierarchy that closely approximated normal vision. The fourteenth-century master painter Giotto di Bondone had intuitively understood how modeling and superpositioning could create the illusion of depth, but some aspects eluded even this great painter. In his rendering of the Pentecostal dinner, Giotto could not solve the perspectivist problem of how those apostles sitting in the foreground were to eat their meal through their solid halos.

  The next important figure to advance the development of perspective was Filippo Brunelleschi. His fame is forever established as the builder of the colossal dome of the cathedral of Santa Maria del Fiore in Florence. Among his other achievements was his invention of a method for drawing a scene with its objects in their proper perspective. Around 1415, he used an ingenious arrangement of mirrors—one had a peephole through which he could peer to create the first geometrically correct perspectivist drawing using a device.

  Seventeen years before Leonardo’s birth, another architect/engineer, the polymath Leon Battista Alberti, published a formal treatise on the subject in 1435. Alberti laid out for artists the steps they needed to master if they were to convey the sense of realism hitherto lacking in previous complex compositions.

  Almost overnight, perspective became the very lodestone that set the direction for Western art. For nearly five hundred years, all Western artists agreed that this was the way to organize a painting. An artist could stray from the rules of perspective intentionally, but these were minor deviations from the main theme that ran through Western art from the onset of the Renaissance to the modern era.* Critics considered an artist unschooled if the art of perspective was amateurish, and it was one of the early skills mentors insisted that young art students learn.

  * Occasionally an artist like the eighteenth-century Englishman William Hogarth purposely violated the rules of perspective to create compelling optical illusions. One of his titles, Satire on False Perspective, belied his tacit recognition that the absurdities he introduced into his picture plane reaffirmed his recognition of the importance of perspective to the Western artist.

  Vasari relates the story of one of the Renaissance greats, Paolo Uccello, who spent hours poring over his studies concerning the intricacies of perspective. One night, his frustrated wife urged him to pull himself away from his drawing board and come to bed. Going reluctantly, as if leaving a lover of superior allure, he was reputed to have muttered as he trundled off, “Ah, perspective, what a lovely thing it is.”

  Chiaroscuro became a painterly technique that accentuated lighted surfaces while simultaneously casting shadows darker than they would normally appear. Artists such as Michelangelo, Caravaggio, and the Dutch painter Johannes Vermeer used chiaroscuro with great effect in their works. The combination of perspective and chiaroscuro greatly enhanced the realism of Renaissance paintings.

  Leonardo made many contributions to the art of perspective, but the one for which he is the most famous was his refinement of chiaroscuro, known as sfu
mato. The Italian term translates as “turning into smoke.” Leonardo observed that due to atmospheric haze, the borders of far-distant objects appear less distinct than those that are closer to the foreground. Distant objects’ colors were less crisp and their shadows less sharp. He greatly increased the effect of perspective by painting distant scenes as if viewed through a layer of gauze, making them less colorful than those in the foreground. Although he was not the first artist to make this observation regarding the nuances of perspective, Leonardo’s mastery of sfumato so surpassed any other artist that his name is inextricably associated with the technique.

  While working at the French court, Leonardo’s familiarity with perspective led him to invent anamorphism, a form of painting that distorts perspective so that the anamorphic (distorted) object, when viewed in the conventional manner from the front of the painting, appears either grossly distorted or as it would appear in a funhouse mirror. In most cases, an anamorphic image embedded in a painting is unrecognizable. When viewed from an extreme angle off to the side, however, the anamorphic object springs out of what is a markedly distorted main image to appear realistically drawn.

  Only someone keenly aware of the laws of perspective and optics, and who possessed an intuitive grasp of algebra, could create such a picture. Anamorphic technique was very difficult to execute. As Leonardo’s example of anamorphism appeared in his notebooks, it is not presently known whether his technique was disseminated out into the artistic community after the pages of his notebooks circulated, or whether the artists employing this technique invented it independently. What is known is that Leonardo’s simple line drawing constituted the first anamorphic image in Western art.

  Given Leonardo’s perfectionist bent and curious mind, it should come as no surprise that he expended untold hours and a considerable number of pages studying the optical science behind perspective. He filled his notebooks with exacting sketches of buildings and other objects drawn within the overlay of a perspectivist grid. Here, then, is a mystery: In his written notes, he exhorts artists to adhere to the rules of perspective and in many instances explains in detail just how they are to accomplish this goal. Yet, this master of the technique routinely violated the rules he so painstakingly explained. As early evidence for the adage “Rules are meant to be broken,” Leonardo’s tampering with perspective was so artful that instead of detracting from his compositions, it enhanced them.

  Leonardo crafted numerous sleight-of-hand perspectivist idiosyncrasies in his The Last Supper (1495–97) [Fig. 3]. The site selected by the monks for the enormous fresco was in the refectory, high on the wall behind the table where the monks took their meals. The painting had to be viewed from below, yet Leonardo strove to achieve the effect that the viewer was looking upon a scene that was essentially at eye level. In art critic Leo Steinberg’s book, Leonardo’s Incessant Last Supper, he enumerated multiple examples in which Leonardo contorted perspective to enliven his most complex masterpiece. None were clumsy mistakes, as Steinberg points out, but rather thoroughly planned tinkering that Leonardo used to make his composition work within the constraints of the rectory’s room.

  For example, the table has thirteen individuals sitting at it, yet it seems to only have eleven place settings. Johann Wolfgang von Goethe wrote an authoritative essay on The Last Supper in which, taking note of the foreshortened table, he commented wryly that if any of the apostles who were standing in the painting decided to sit down, they would find themselves in the lap of another apostle. The figure of Jesus is one and a half times larger than his dinner companions, though this distortion of perspective is only evident after close scrutiny. The room in which the action takes place appears at first glance rectangular. Looked at another way, it becomes an expanding trapezoid.

  Leonardo intuited that a person’s face, despite appearing symmetrical, is actually divided into two slightly different halves. Because of the crossover in sensory and motor nerves from each side of the face within the brain, the left hemisphere controls the muscles of the right side of the face and the right hemisphere controls the muscles of the left side. The majority of people are left-brained/right-handed, which means that the right half of their face is under better conscious control than their left. In contrast, the left half of the face connects to the emotional right brain, and is more revealing of a person’s feelings. Right-handers have more difficulty trying to suppress emotional responses on the left side of their face.

  In a recent psychology experiment, a group of unsuspecting college students were ushered into a photographer’s studio one at a time and informed that they were to pose for a picture to be given to members of their family. The majority of these right-handed students positioned themselves unaware that they were turning the left side of their face toward the camera’s lens. All of them smiled.

  Brought back a second time, the researchers informed them that, now, they were to pose for a job application photo. In this case, they adopted a more professional demeanor, and the majority of right-handers emphasized the right side of their face. The results of this experiment, along with several others of similar design, strongly suggest that unconsciously, most people know that the right side of their face is best to present to the outside world. They are also subliminally aware that their left side is a more natural reflection of who they really are.

  Leonardo understood these subtleties of expression. Mona Lisa is best appreciated by observing the left side of her face. Heightening the ambiguity of her smile, Leonardo chose to highlight the right side of her face and place the left in shadow.

  Leonardo initiated several other innovations that now seem so commonplace we have difficulty imagining just how revolutionary they were to their time. Earlier portrait painters included only the sitter’s upper chest and head. In the mid-fifteenth century, a few Flemish artists began to widen the focus to include the subject’s hands. The historical evidence is unclear as to whether or not Leonardo saw examples of what his northern colleagues were doing, or if he arrived at the notion of including hands in his portraits independently. Nevertheless, Leonardo took full advantage of this enlarged scope, recognizing more fully what had escaped the attention of the earlier Flemish painters: the importance of gesture.

  Leonardo’s accentuation of a subject’s hands was an elegant substitute for the expressiveness of speech. Oral human communication is a complex combination of speech and body language. The ear and the eye work in concert to ferret out the true meaning of the speaker’s message. Speech is received by the ear, and the left brain busily attends to the linear arrangement of incoming words transmitted by the inner ear. The listener gathers revealing information by assessing the speaker’s facial expressions, his or her clothes, grooming, body language, and hand gestures, along with those involuntary reflexes that cause, on occasion, pupil dilation, perspiration, or blushing. In some cases, gesture is superior to speech. Ask anyone to describe a spiral staircase. As their words falter, their hands will invariably trace a corkscrew motion that more accurately conveys the concept better than either the spoken or written word can. Psychology researchers estimate that listeners decipher as much as 80 percent of a message from nonverbal clues.

  Portraits cannot speak. Leonardo sought a way to express with a brush the essence of his subjects’ personae. Including hands in his portraits was an important part of Leonardo’s dictum that the artist must not only reproduce a faithful copy of his subject, but must also try to depict the subject’s state of mind.

  In a portrait he completed soon after arriving in Milan (Lady with an Ermine, c. 1489), that of Sforza’s sixteen-year-old mistress, the beautiful Cecilia Gallerani, he intentionally elongated the fingers of her hand [Fig. 4]. Combined with her narrow face, her fingers accentuate her willowy form. He also painted her holding an ermine, the name of which is connected symbolically to the House of Sforza. Additionally, the small mammal had a reputation for fastidious cleanliness, a metaphor that extolled Cecilia Gallerani’s wholesome nature. And the Greek word
for ermine is gallan, another clever play on words and images that Leonardo used to insinuate her family name into the picture. By positioning his subjects’ hands just so and sometimes giving them something symbolic to hold, Leonardo augmented their facial features and increased the viewer’s access to the subject’s inner state of mind.

  In the middle of the nineteenth century, a Swiss draftsman, Rodolphe Töpffer, extensively examined the nuances of caricature.* Art historian E. H. Gombrich grants Töpffer pride of place as the father of this form of art. Caricature was but another new form of visual communication, an alternative means to convey emotions and viewpoints. Cartoonists make us laugh, satirists make us think, and the political cartoonists’ daily offerings are often more penetrating than the editorials appearing alongside them. Töpffer’s tribute aside, Leonardo can rightfully lay claim to being one of history’s greatest caricaturist. He filled his notebooks with drawings of faces he distorted, emphasizing prominent features while minimizing others—the essence of caricature. His drawings in this genre zigzagged the fine line separating the grotesque from the comical. No previous artist had exaggerated human faces to the extent that Leonardo had.

  * Caricature is named after the Italian artist Agostino Carracci, who, around 1600, created images of faces that were distorted. At the time, only a few artists were aware of Leonardo’s work. Although we cannot know for certain, it is not unreasonable to speculate that Carracci, who lived and worked in nearby Bologna, would have known of Leonardo’s work.

  Landscape painting, sfumato, anamorphism, caricature, the inclusion of hands in portraits, and sophisticated observations concerning facial expressions are among the innovations that Leonardo slipped into the Renaissance’s swelling art stream. Leonardo profoundly affected the art of his time, and his influence extended far and wide among the generations of artists that followed him. But, another aspect of Leonardo’s art, not as thoroughly chronicled, was his uncanny ability to invent the principles that undergird modern art. How did a Renaissance artist anticipate so many of the explosive and revolutionary art movements that have come to define “modern art”?