The Primeval Feature

The Face: A Natural History
By Daniel McNeill

(Page 8 of 12)

If we view the face as a geography, it is two long forests, a pair of multicolored sunken lakes, a Gibraltar-like peak, and an abyssal pit. The pit is the most dramatic item on the map, and it is of course the mouth.

The mouth is the oldest part of the face, the gateway for food, drink, and at times air. It is primal, essential. Even the one-celled paramecium has a mouth. We can survive outside a hospital without eyes, nose, or any other facial feature, but without a mouth we starve. Pliny cites learned authority for the existence of the Astomi in Pakistan, who lack mouths and live on the aroma of roots, flowers, and apples. In fact, some simple creatures do lack a mouth and absorb food through their "skin." But it is vital for any kind of digestive tract.

The mouth is the first facial organ to form. It arises in embryos soon after fertilization, in the process called gastrulation. A dent appears in the spherical embryo and deepens, pulling in the cells that will make up the muscles and inner organs, and forming the gut. When this tube reaches the far end of the embryo, it breaches the cell wall and creates the mouth.

This aperture is the body's main entrypoint and guards hedge it about. Before swallowing food we test odor, taste, texture, temperature, shape, and irritability, and we have a gag reflex to stop it at the last minute. Our emotions also patrol this ground. For instance, saliva feels normal in the mouth, but spit some in a glass of water and it becomes instantly repulsive. Yet it is the same saliva.

The mouth is the most plastic part of the countenance. Eyes move constantly but subtly, in a delicate shimmy of jumps and tremors. The mouth often rests, but once in motion, it can sigh, yawn, smile, laugh, drop open, pout, tremble, and tighten. When we speak, the mouth moves in seemingly endless ways: widening, opening, closing, puckering, protruding, retreating. And if we like, we can twist the mouth into weird topologies. It is the contortionist of the face.

Our mouth sets us apart from other creatures in several ways, but the most striking is its narrowness. Human mouths are usually no wider than the span between the pupils, a surprise to most beginning portrait artists. Some fish like carp also have tiny mouths, which they use for suction feeding, but they and we stand almost alone. Indeed, next to us even chimps have huge maws, running hairline to hairline, and horse and alligator faces are almost all mouth. Why did ours shrink?

First, because it could. Muzzles need wraparound mouths, but ours is free from this constraint and has evolved to different ends. One is protection. Since we don't use our teeth as weapons, the mouth need not be wide, and a small one is safer from contaminants. Another is probably expression. The face muscles can control small lips more deftly, enhancing our array of smiles and grimaces. A third may be language. Sounds like "oh" and "w," for instance, require the lips to form an O.

Intriguingly, the large mouth has rarely been a sign of beauty, but the small mouth has. In Victorian times, especially, a tiny mouth was dainty. Trollope's women often had such a mouth, as did Dickens's Little Nell.

The mouth is the home of two notable facial transients: the teeth and the tongue.

Teeth are performers, beaming into view as we speak and smile. They give the face delicious volatility and can dazzle us with their ivory gleam. "Toothsome" describes a form of beauty and radiant teeth seem the reward of a smile. Firenzuola said the teeth impart "so much charm to a pleasant face that, without them, sweetness does not seem to reside too willingly upon it." Their secret is less sublime: saliva. It coats the teeth with water, so they gleam in the light.

Teeth last longer than any other part of the face-not surprisingly, since enamel is the hardest biological substance known. South American cannibals made necklaces from the teeth of devoured enemies. States have warred to own a tooth of the Buddha, who preached against ownership. The most precious tooth on earth today came from the Buddha, we are told, and resides in a gold vessel in Kandy, Sri Lanka. Gary Snyder, who viewed the plaster cast of it, said it was two inches long.

Modern teeth arose with the advent of jawed fish around 440 million years ago. Only jaws can grip, manipulate, cleanly cut, and grind prey. The first jawed fish, the sardine-sized acanthodian, prowled the seas until 260 million years ago. Its teeth were tiny stilettos like piranhas', but teeth quickly radiated into cones, blades, and crushers.

Teeth reach their apex in mammals. Most other animals use them mainly to seize prey. But mammal teeth can shear, crush, and grind food. They allow chewing, a notable power. Chewing speeds digestion and puts more of the natural world on the menu. It also leads to a dextrous tongue, for nudging food into position, and to polymorphic teeth.

Mammals boast a more complex array of teeth than other animals, an intricate palisade of incisors, canines, premolars, and molars. The incisors are the blades, cutting bites from carrots and apples. Canines, our relic fangs, have deep roots and handle tough foods like jerky. The premolars and molars crush food into pulp for the stomach. Behind the molars lurk wisdom teeth, which often never emerge. (They may in fact be evolving away, since with our flat faces we need fewer teeth.) Teeth have diversified so much in mammals that a paleontologist can often identify a genus and even a species from a single tooth.

People fiddle with the face and have altered every part of it, even, with laser surgery, the eyeball. They have throughout history improved on teeth. Pre-Columbian Indians of Mexico added inlays of jadeite, pyrite, gold, and turquoise. Tribes have notched, grooved, scratched, perforated, and sculpted their teeth, and in Mesoamerica alone, dental anthropologists have identified 59 different types of tooth mutilation. The Baule of Ivory Coast often remove a diagonal half of each front incisor, creating a black triangle when they smile. The Kadars and Malavedans of southern India file their teeth into points, as do the Tiv of Nigeria. Tiv soldiers stationed in Cairo found, to their delight, that Egyptians thought they were cannibals, and they quickly learned that fierce faces in the bazaar won them breathtaking bargains.

Dracula has sharp white teeth that extend over his lips-fangs, essentially. But most people prize well-ordered, soldierly teeth. Precontact Inuit and aboriginal Taiwanese had perfectly aligned teeth, but the modern diet of soft, refined foods has jumbled them. Etruscan girls wore braces as early as 700 b.c., and today orthodontic treatment is the greatest precollege expense most parents lay out for their children. Diet also fosters decay, and dentists plug caries and replace teeth that fall out. These are the most common repairs we make on the face.

We speak with the tongue and a talkative person is a "tongue-pad." Yet this odd and agile organ rarely emerges onto the face, and its appearance is often aggressive. We stick tongues out to insult people, a gesture that smacks of the child. The classic Medusa pokes out her tongue, and the Maoris howled their unnerving war cries with tongue far out. Indeed, they carved knives with a face as hilt and a tongue as glinting blade.

A tongue in the cheek is more ambiguous. Smollett's Roderick Random says, "I signified my contempt of him, by thrusting my tongue in my cheek." But today "tongue-in-cheek" means ironically, not to be taken seriously. In modern Western society, a real tongue nestled in the cheek suggests hesitancy, pondering.

The tongue can express other feelings. Run lusciously across the lips, it is a classic sexual invitation. A slightly protruding tongue can imply uncertainty. One turned downward suggests bewilderment, and most of us have seen the gesture of goofy delight-wide grin, tongue down, eyebrows raised-signifying surprise achievement: "I don't know how I did that!"

Fish lack tongues. They commonly seize food by sucking water into their mouths, a trick that utterly fails in air, so when fish first ventured onto land, they sprouted tongues. Old World chameleons can dart their tongues out more than a body length to snare insects. Most birds have tiny tongues, but the flamingo has a thick, esculent one, and Roman emperors Elagabalus and Vitellius fed guests heaping bowls of them.

We think of the tongue as a single muscle, but it is actually a bundle of them which can shorten, lengthen, and widen it. Muscles outside the tongue also tug it, so it changes shape deftly, a key fact for speech. Some people can roll their tongue into a tube and others can't. It's a genetic variation of baffling purpose.

The flare-like papillae on the tongue contain most of our 10,000 taste buds, though these sense organs also dot the palate, larynx, and pharynx. Most register not just one taste, but several, and thus send information in polyphony to the brain.

The tongue helps us swallow, and we do so about nine times a minute while eating, once a minute while not eating. The latter act is unconscious and salutary. Saliva coats many microorganisms with mucus, and swallowing takes them down to the stomach, where gastric acids annihilate them. Billions of other bacteria inhabit the mouth, a large proportion on the tongue. Most are benign, and many form one more rampart of the body's defense.

Outside, the mouth is a little duchy, like the eye, and many vassal features lie in its sphere. Most notable are the philtrum, nasolabial folds, chin, and lips.

The philtrum is the shallow vale between the nose and upper lip. It rarely attracts attention on its own, but where its two ridges touch the mouth, the lip rises to meet them. In between, it dips slightly. The philtrum thus fathers the graceful notch in the upper lip.

The nasolabial folds flank the mouth. These two creases slant out tentlike from the wings of the nose down past the lips, bounding the cheek. Age deepens these pleasant lines into character marks. Since they magnify smiles and other mouth expressions, they are key signals of mind-state. Yet not one person in a thousand can name them.

The nasolabial folds vanish in a paralyzed face, but not in a corpse. Why? In our daily life nerve impulses pull the folds up and back somewhat. Paralysis halts these signals and the skin turns smooth. Yet after death the muscles freeze in slight contraction, and the lines live on.

The chin is unique to humans. Not even Neanderthals had one. It appeared around 130,000 years ago, with the first anatomically modern people, and it remains a puzzle.

It is not utterly pointless. It seems to aid mastication, though its arrival coincides with no known shift in diet or subsistence pattern. And it clearly sets faces off and helps us lock onto them better. As hair frames the top half of the face and jawline the sides, the shadow of the chin marks the bottom. In profile, its jut signals the base, like a serif in typography. Without a chin, the lower face would merge with the neck, and face shape would blur.

Such uses don't necessarily explain its origin. Indeed, it may be inadvertent. Some believe it simply appeared when the muzzle retreated, much as islands emerge when sea level drops in an ice age. The mouth flattened faster, leaving a bony knob that recalls our nipping and gnawing days.

Darwin observed that relics like the appendix take more diverse forms than other organs. They have lost their utility, so most variations in them are not harmful and persist. If the chin is actually a remnant of the muzzle, it should come in many shapes and sizes, and in fact it does: soft, cleft, jutting, dimpled, long. Ironically, this variety has become a use in itself, multiplying the range of possible faces and distinguishing us.

The chin is crucial to looks. A slight chin is unattractive, especially in men, and hence another theory involves sexual selection. In males, the chin grows during puberty in response to testosterone, so larger chins suggest its greater presence. Since testosterone weakens the immune system, its excess is an "honest" signal of good health in men, advertising their ability to resist disease. Hence women may have evolved to like large chins. George Williams suggests that, today, male chins may be developing into sexually selected structures like the antlers of Irish elk, and in fact the average size of chins has grown over the last 200 generations. They are expanding, not retreating.

At rest, the mouth is pure lips. Lips are the spice of the face, twin ruddy bulges separated by the dark line of the mouth, like a pair of cushions. They can be thick or narrow, bulging or inswept. At rest they can seem to pout, frown, or smile, and some lips form a "cupid's bow." All are a transition zone between the dry skin of the face and the moist mucous membrane of the inner mouth. Their surface is thin enough to reveal blood below, so lips look dark.

Lips are border guards. They excel at distinguishing foreign objects, and can detect a single hair in our food. They lie in the forefront of our oral defenses.

But lips also serve subtler ends. For instance, they cue us to speech. We read them subliminally, which is why out-of-sync dubbing in foreign films bothers us. Lips are especially helpful in borderline cases. In one study, people recognized 23 percent of sentences uttered in noise, but 65 percent when they could also see the speaker's face. Noise has bedeviled speech recognition technology, and the face could help cut through it. Says Dominic Massaro of U.C. Santa Cruz, "You can go from chance to perfect by just having the face." Massaro is seeking to supply the deaf with glasses that distinguish visually similar sounds, like ma and ba, by flashing different colors.

Indeed, we rely so heavily on lip signals that they breed the strange effect called the McGurk illusion: People presented with the sight of one mouthed phoneme and the sound of another typically hear it as a blend of the two. Visual ga and aural ba, for instance, yield da. We are hearing partly with our eyes.

Ventriloquists speak liplessly. The trick is ancient. Inuit magi used it, and Zulu shamans made warnings seem to issue from the wattles of their huts. Greek and Roman ventriloquists claimed divine spirits spoke from their stomachs-hence the name, which means "belly-talking." In the sixteenth century, belly-speaker Elizabeth Barton, the "Holy Maid of Kent," drew thousands of pilgrims to hear her prophecies against the second marriage of Henry VIII. He had her hanged at Tyburn in 1534. In rural China, female ventriloquists sometimes spoke through little dolls on their stomachs, but the ventriloquist's dummy did not become common until the latter nineteenth century.

"If a man is not born a ventriloquist, he will never become one," said Victorian ventriloquist Walter Cole. Such claims swathed him and other adepts in a useful mystique, but in fact people learn the art, as they learn magic and juggling. The illusion has two parts. First, performers must create a second voice. Edgar Bergen must sound like Mortimer Snerd. To do so, they hump up the rear of the tongue, as if uttering an ng, and force part of the vocal tone through the nose. Second, they must speak with still lips. The main hurdle is producing b, p, and m inside the mouth. Ventriloquists make the b and p by placing the tip of the tongue on the front teeth, and the m by touching the rear of the tongue to the roof of the mouth. These feats demand the patience of Demosthenes.

The lips also enhance facial expression. They enlarge the rim of the mouth and thus highlight smiles, sneers, and gapes. We pull the lips tightly in to conceal expression, much as we put a hand over the mouth.

And, most obviously, lips give sensual delight. They are twin pleasure puffs, rich with touch sensors. Lips are part endoderm, like the lining of the gut, and their boundary with the skin or exoderm forms a line between inner and outer self. It means that, when we kiss, our inner selves touch.

© 1998 by Daniel McNeill

About the Author

Daniel McNeill is a bestselling author and winner of the Los Angeles Times Book Prize for The Face. Mr. McNeill is the principal author of Fuzzy Logic, which won the 1992-93 Los Angeles Times Book Prize for Science and Technology. He has written numerous other books and articles on high technology, and his work has also appeared in fiction, travel, history, law, and education publications. He lives in Southern California.