Kevin Portillo practises smiling every day at home. Usually after brushing his teeth. Or when stopping by the bathroom, or anywhere with a mirror.
He hooks an index finger into each side of his mouth and pulls gently upward. He puckers his face into a kiss, then opens wide into an O, trying to limber up his facial muscles. He practices both the Mona Lisa–slight, closed-lip–and a wide, toothy smile.
At least, he’s supposed to do his exercises every day. Being 13, he sometimes forgets, though he understands their importance.
“I need to stretch my cheeks,” he says. “I do it for a couple minutes. I have to do it every single day.” He exercises so much that his jaw sometimes hurts.
Kevin was born in New Jersey with a rare malignant vascular tumor, a kaposiform haemangioendothelioma, covering the left side of his face, squeezing shut his left eye and pushing his nose to the right. Immediately after his birth, doctors whisked him away to another hospital in another state–the Children’s Hospital of Philadelphia. His mother didn’t see him again until he was eight days old.
The doctor told Kevin’s parents that the chance of him surviving was slim.
But survive he did. However, the large tumor and the damage from its treatment prevented him from being able to do one of the most fundamental things humans do.
The second signal babies send out is a smile. Newborns can smile spontaneously, as a reflex. This is sometimes misinterpreted by new parents as a reaction to their presence, a reward for their intense concern and sleepless efforts. However, it’s not until six to eight weeks of age that babies smile in a social way. Blind babies do this at the same time.
That new parents sometimes optimistically interpret the first reflex smiles as meaning something more underscores the duality of smiling: There is the physical act and then the interpretation society gives to it.
On a physical level, a smile is clear enough. There are 17 pairs of muscles controlling expression in the human face, plus a singular muscle, the orbicularis oris, a ring that goes entirely around the mouth.
When the brain either reacts to a stimulus spontaneously or decides to form an expression intentionally, a message is sent out over the sixth and seventh cranial nerves. These branch across each side of the face from the eyebrows to the chin, connecting to a combination of muscles controlling the lips, nose, eyes, and forehead.
The basic upward curving smile is achieved primarily by two pairs of zygomaticus muscles, major and minor. These connect the corners of the mouth to the temples, tugging lips upward–often accompanied, depending on the underlying emotions and thoughts, by the levator labii superioris, raising the upper lip, and other muscles of the face.
And as for the oft-cited folk wisdom about how it takes more muscles to frown than smile, the jury’s still out, especially as different smiles require different numbers of muscles. However, one source suggests that a genuine smile takes about as many muscles as a frown (and that a particularly insincere kind of smile might take not much more than the pair of risorius muscles).
It is when we leave the realm of physiognomy, however, that the smile becomes enigmatic. This contraction of various facial muscles resonates across the entire arc of human history, from the grinning Greek kouros sculptures of 2,500 years ago right up to emoji, those little images that pepper our online communications.
One study of smartphone users from 60 countries showed that emoji with smiling faces are by far the most prevalent in messages. The most popular overall–the face with tears of joy–was picked as the 2015 Word of the Year by Oxford Dictionaries.
Just as this emoji expresses more than mere happiness–tears adding the ironic twist so popular online–smiles themselves can convey so much more than happiness. Interpreting their nuances is a challenge whether dealing with art history or interpersonal encounters or the cutting edge of artificial intelligence.
A 2016 study, published in the Journal of Nonverbal Behavior, questioned thousands of people in 44 cultures about sets of photographs of eight faces–four smiling, four not.
In most of these cultures, people deemed the smiling faces to be more honest than the non-smiling ones. This difference was huge in some countries, such as Switzerland, Australia, and the Philippines, but small in others, such as Pakistan, Russia, and France. And in a few countries, such as Iran, India, and Zimbabwe, there was no trustworthiness benefit to smiling at all.
Why? That question is also complicated, but in essence, the researchers concluded it has to do with whether a society is set up so that its members assume that other people are dealing with them honestly. “Greater corruption levels decreased trust granted toward smiling individuals,” the authors concluded.
That attitude harks back to a very old view of smiling as being opposed to pious solemnity. There is exactly one smile in the Old Testament–Job, ironically–though in many passages faces are said to “shine,” which could mean smiling or could mean heavenly radiance.
Eastern religions often use the smile to denote enlightenment. The literal name of the thousand-year-old Flower Sermon, which describes the origin of Zen Buddhism, is “Pick up flower, subtle smile.” The Buddha and various religious figures were depicted with serene smiles, though the original Buddhist texts are as devoid of smiling as Western scripture. Jesus weeps but never smiles.
Nor did Kevin Portillo, not fully. He did not smile on schedule. At five weeks old he was already a week into chemotherapy with vincristine, an anticancer drug so powerful it can cause bone pain and skin rashes. Doctors warned his mother that the treatment might leave him blind, or deaf, or unable to walk.
“If he survived,” says his mother, Silvia Portillo, in Spanish, speaking through a translator. “The doctor always said he could not give us hope that he would survive.”
Whether stunted due to the tumor or killed by the chemo, Kevin’s seventh cranial nerve withered. That nerve originates at the brainstem then branches out across the face. It is susceptible not only to tumors, as in Kevin’s case, but also to rare conditions such as Moebius syndrome, a congenital facial paralysis caused by missing or stunted cranial nerves. You can’t smile, frown, or move your eyes from side to side.
“You essentially have a mask on your face,” says Roland Bienvenu, 67, a Texan with Moebius syndrome.
Without being able to smile, others “can get the incorrect impression of you,” says Bienvenu. “You can almost read their thoughts. They wonder, ‘Is something wrong with him? Has he had an accident?’ They question your intellectual ability, think maybe he’s got some intellectual disability since he’s got this blank look on his face.”
A lopsided smile can be as problematic as no smile at all.
“I have half a smile, so even with that I am able to successfully convey emotion,” writes Dawn Shaw, born with a teratoma, a fast-growing tumor that was interfering with her windpipe. “The hardest part for me was seeing photos of myself smiling, because smiling exaggerates the fact that half my face doesn’t move very much. But eventually I learned to own it. That is me. That is how I look.”
The challenges stemming from lack of a smile are frequently compounded. When people have a medical condition severe enough to keep them from smiling, other difficulties tend to be involved.
“He was different than the other kids,” says Silvia of her son. “He was fed for four years through the G-tube in his stomach. He wasn’t able to have a normal life, because every few hours he had to be connected to the machine to be fed.” Little kids, being curious, would look and ask what happened to him, she says.
While those who cannot smile can blame the state of their facial nerves and muscles, those who can smile are often concerned with a different aspect of physiognomy: their teeth. More than $3 billion is spent worldwide on teeth-whitening products, with billions more spent on braces and on purely cosmetic dentistry: straightening crooked teeth, for instance, or reducing the amount of gum that shows when a person smiles.
Caring for the state of your teeth is not a modern concern. The Romans had dentists and used chewing sticks and toothpaste. They preferred dazzling white smiles, sometimes rinsing their teeth in urine to enhance the effect.
Contrary to common modern perceptions, the ancients had surprisingly good teeth, for reasons that have nothing to do with dentistry. A CAT scan of 30 adult bodies recovered at Pompeii found they had “perfect teeth.”
This was due to two factors: short lifespans–they didn’t live long enough for their teeth to go bad–and, most importantly, lack of access to refined sugar, that great destroyer of dental health.
When piety was an overarching value, smiles were, well, frowned upon as the precursor of laughter, which was held in true disdain. Prior to the French Revolution, broad smiles in art were overwhelmingly the realm of the lewd, the drunk, and the boisterous lower classes.
“The whole face ought to reflect an air of seriousness and wisdom,” John Baptist de La Salle wrote in his 1703 The Rules of Christian Decorum and Civility, allowing that people might, under certain circumstances, convey the impression that they are happy, provided it is done within limits.
“There are some people who raise their upper lip so high or let the lower lip sag so much that their teeth are almost entirely visible. This is entirely contrary to decorum, which forbids you to allow your teeth to be uncovered, for nature gave us lips to conceal them . . . ”
In The Smile Revolution in Eighteenth Century Paris, Colin Jones argues that smiling reflected the gathering sense of individual worth that went along with the beheading of kings:
This shift in social practices and in sensibilities involved the emergence of the perception, common in our own day, that the smile offered a key to individual identity. In late eighteenth-century Paris, the smile came to be viewed as symbol of an individual’s innermost and most authentic self. In a way that was perceived as both novel and modern, it was held to reveal the character of the person within.
Photography, by capturing smiles, eventually helped popularize them. But the sitters in 19th-century photographs still rarely smiled, a neutral continence being both easier to hold over the long exposure necessary at the time and less likely to detract from the gravity of the occasion.
“A photograph is a most important document, and there is nothing more damning to go down to posterity than a silly, foolish smile caught and fixed forever,” humorist Mark Twain was quoted as remarking in the 1913 memoir of an acquaintance.
Around the same time, however, Kodak in the U.S. launched extensive advertising campaigns to help consumers see photography as a means of recording joyous events and celebrations.
Over the century, smiles showed a confidence in keeping with the rise of modern capitalism. “An insincere grin? That doesn’t fool anybody,” Dale Carnegie wrote in his 1936 bestseller, How to Win Friends and Influence People, embraced as a life guide by millions.
“We know it is mechanical and we resent it. I am talking about a real smile, a heartwarming smile, a smile that comes from within, the kind of smile that will bring a good price in the marketplace.”
Part of the attractiveness of smiles is they are so easily extended. Part of their menace is that they can also be just as easily withheld.
“For a salesman, there’s no rock bottom to the life,” Charlie says at the end of Arthur Miller’s Death of a Salesman. “He don’t put a bolt to a nut, he don’t tell you the law or give you medicine. He’s a man way out there in the blue, riding on a smile and a shoeshine. And when they start not smiling back–that’s an earthquake.”
Once Kevin was able to eat food, go to school, and enjoy usual childhood pastimes–he became passionate about soccer and playing the drums–he still felt the tremors of having a half-smile in a world solidly established upon “a cultural expectation of pearly perfection,” as Richard Barnett writes in his book The Smile Stealers.
“I couldn’t smile on my left, I only smiled on my right,” says Kevin. “My smile was weird . . . people kept asking what happened to me, why I’m like this. I keep telling them I was like this when I was born.”
If you see someone in a wheelchair, you anticipate that the person might have trouble walking and assume a physical condition is involved. But facial paralysis carries no telltale equipment, and is rare enough that the unaffected population is not generally familiar with the conditions that cause it, whether congenital or appearing later in life.
One of the latter is Bell’s palsy, an inflammation of the sheathing around the facial nerves on one side that paralyses half the face, causing the eye and corner of the mouth to droop. It usually strikes men and women between the ages of 15 and 60.
In most cases temporary, Bell’s palsy generally slowly goes away as mysteriously as it arrives. Doctors suspect it is caused by a viral infection. There are also traumatic events–car wrecks, sporting accidents–that damage nerves and muscles in the face, plus congenital irregularities such as cleft palate.
A common condition that can also affect the smile is stroke. A sagging smile or face drooped on one side is one of three signs that a person has had a stroke and needs immediate emergency care (the other two are weakness or numbness in one arm and slurred or garbled speech).
While losing a smile is a serious blow at any age, it can have a particular impact on younger people, who are starting out, forming the bonds that will carry them through the rest of their lives.
Or trying to.
“It’s a huge problem,” says Tami Konieczny, supervisor of occupational therapy at the Children’s Hospital of Philadelphia (CHoP). “When you look at somebody, the first thing you see is their face, their ability to smile or not smile, or an asymmetrical smile. It’s your social world.
“If someone can’t read your facial expressions, then it’s difficult to be socially accepted. It’s hugely devastating for kids. I had kids photoshopping their pictures. They are taking mirror images of their good side and copying it, photoshopping their own pictures before posting them to social media.”
Photoshopping might work on Facebook. But fixing a smile bisected by nerve damage and subsequent muscle loss–Kevin couldn’t move the muscles on the left side of his face, so they atrophied–is far more complicated. Sometimes, it requires multistage plastic surgery spread out over a year or more.
There are two major procedures available for facial reanimation, according to Phuong Nguyen, a plastic surgeon and reconstructive surgeon at CHoP.
The newest, which has its roots in older techniques, is called a lengthening temporalis myoplasty, taking part of the broad band of muscle that powers the jaws and repurposing it to draw up the lips.
That wasn’t ideal for Kevin because he had one side of his face working. The older, more complicated surgery was better suited to him.
“Kevin had the most commonly done one, a classic two-stage cross-face nerve graft followed by a free gracilis muscle transfer,” says Nguyen. “To be perfectly honest, when Kevin had his stage, we weren’t familiar with the lengthening temporalis myoplasty procedure yet.”
Nguyen later learned the new procedure from facial reanimation pioneer Ronald Zuker, a Canadian plastic and reconstructive surgeon, and from its originator, French surgeon Daniel Labbé.
“My preference is to do it when kids are five years of age,” says Zuker. “At the time, if I can restore a smile for them, they can go to primary school, meet kids on the playground, meet kids in class. They have their smiles and are well-equipped to handle that situation.”
Why put children through what is still elective surgery?
“It’s incredibly important to be able to interact with humans on a face-to-face basis,” says Zuker. “If you don’t have the ability to smile, you are at a disadvantage. People cannot understand your inner emotions. They mistake your appearance for being disinterested, or not too bright, or not very involved in the conversation.”
Still, some parents prefer to wait until their children are older and can participate in the decision.
“If families want to wait, that’s perfectly fine,” says Zuker. “Sometimes when a kid is 9 or 10 they look in the mirror and say, ‘You know, I really want this surgery.’ That’s the time to do it.”
Which is what happened with Kevin. He was doing well, “even with that scar on his face, has always been popular at school,” says his mother. “He’s always been a happy kid.”
But there were kids that made fun of him, she says. One day when he was about 9, he was sad. “I said, ‘What happened to you?’ He said, ‘Some kids, they’re not my friends. They laugh at me because I look funny.’ It was really hard for us as parents.”
“We always wanted the surgery,” she says. “But we were told it was impossible. We had to wait to see how everything was changing.”
At age 10, Kevin told his parents that he wanted to do what most people do without giving it a second thought. He knew it would be a long, painful, difficult procedure, but it was one he wanted to undergo.
“He’s very engaging, very motivated,” says Anne-Ashley Field, his occupational therapist at CHoP. “His goal, I wrote in my notes, was to have a symmetrical smile.”
As with smiles themselves, so the scientific study of smiles reflects the cleavage between the physical and the interpretive. The physical side is entwined with the long history of plastic surgery, which has tended to focus on survivors of diseases like syphilis and of the knives of vengeful authorities and warlords.
The father of modern plastic surgery, Harold Gillies, reported in 1934 that restoring the ability to smile made patients’ faces “feel much more comfortable.” In addition, Gillies observed, “the psychological effect is also one of considerable value.”
On the interpretive side, Charles Darwin discusses the meaning and value of smiles in his 1872 landmark The Expressions of the Emotions in Man and Animals. Like many, Darwin sees a smile as the first part of a continuum.
“A smile, therefore, may be said to be the first stage in the development of a laugh,” he writes, then reverses course, musing that perhaps the smile is instead the remnant of laughter.
He observes his own infants closely, detecting in two their first smiles at six weeks, and earlier in the third. He comments how smiles do more than merely convey happiness, mentioning the “derisive or sardonic smile” and the “unnatural or false smile,” and showing photos to see if his associates can read what they mean.
The scientific study of smiles finds differences in gender (generally, women smile more) and culture. Smiles are definitely communicative–people smile more when in public than they do when alone, and more when interacting with others than when not.
Scientists have shown that smiles are far easier to recognize than other expressions. What they don’t know is why.
“We can do really well recognizing smiles,” says Aleix Martinez, a professor of electrical and computer engineering at Ohio State University and founder of its Computational Biology and Cognitive Science Lab.
“Why is that true? Nobody can answer that right now. We don’t know. We really do not know. We have a classical experiment, where we showed images of facial expressions to people, but we showed them very rapidly . . . 10 milliseconds, 20 milliseconds.
“People can detect a smile even in exposures smaller than 10 milliseconds. I can show you an image for just 10 milliseconds and you can tell me it’s a smile. It does not work with any other expression.”
Fear takes an exposure time of 250 milliseconds to recognize–25 times as long as a smile, “which makes absolutely no sense, evolutionarily speaking,” Martinez says. “Recognizing fear is fundamental to survival, while a smile . . . But that’s how we are wired.”
Studies have shown that smiling faces are judged as more familiar than neutral ones. And it’s not just us that can recognize smiles more easily. “This is true both for humans and for machines,” says Martinez. Alibaba, China’s answer to Amazon, launched its new facial recognition payment system called “Smile to Pay” in September 2017.
Although scientists have been studying smiles for about 150 years, they are still at the stage of trying to count and categorize types of smile among the millions of possible facial expressions.
“One of the fundamental questions in the scientific literature right now is how many facial expressions do we actually produce?” says Martinez. “Nobody knows.”
Scientists such as Martinez theorize that smiles–as well as frowns and other facial expressions–are remnants of humanity’s distant pre-linguistic heritage. Human language started developing as far back as 100,000 years ago, but our expressions reach back further still, even to before our origins as human beings.
“Before we could communicate verbally, we had to communicate with our faces,” Martinez says. “Which brings us to a very interesting, very fundamental question in science: Where does language come from? Language is not fossilized, not found in any other living species. How could something that complex have evolved from nothingness?”
One of the hypotheses is that it evolved through facial expression of emotion, he says. “First we learned to move our facial muscles–‘I’m happy. I feel positive with you! I’m angry. I feel disgust.’ Then language came through a grammaticalization of facial expressions, which over time evolved into what we call grammar and language.”
In October 2015, Nguyen, who plays in a band, cranked up some rock music in the operating room at CHoP–he thinks it was probably something from the Smashing Pumpkins album Siamese Dream.
He began work by removing a section of sural nerve from Kevin’s right ankle and attaching it to the working right side of his face, running it underneath his upper lip, to the paralyzed left.
“We bring it across, parking it, waiting for nerves to regrow from the right side to the left,” Nguyen says.
That growth took almost a year. The nerve fibers advanced about a milimeter a day (about 24,000 times slower than a snail).
In nerve grafts like this, many of the fibers don’t make it across. This means that the nerve can lose the ability to transmit information–in a few cases, completely.
“The thing with nerve-based surgery, you don’t get a lot of instant gratification or feedback,” says Nguyen. “You do the procedure and don’t know if it works or not. You have to wait.”
During that time, doctors would periodically tap areas of Kevin’s cheek, to see if the nerve was taking. “When it tingles, you know the nerve is growing,” says Nguyen.
The body has a way of covering losses. Removing that nerve did cause a small patch of skin on Kevin’s ankle to go numb. But as he was still growing, the numb patch began to shrink as the neural network took over its function.
Once Nguyen was certain the nerve was in place and functioning, it was time for the second stage of the surgery.
One morning in August 2016, he took a purple marker and wrote a “P” on Kevin’s left temple and an “NP” on his right, for “paralyzed” and “not paralyzed,” a common surgical precaution against the risk of cutting into the wrong side of a patient–easier than you might imagine, considering how much of a patient’s body is draped before surgery.
“It happens,” says Nguyen. “You want to make it idiot-proof.”
He also drew a pair of parallel lines, marking the location of a prime artery, and an arrow: the vector Kevin’s smile would take.
The surgeon made an incision from the temporal hair line, in front of Kevin’s left ear, then pivoting back under and behind it, extending into his neck–the standard location for hiding plastic surgery scars. The skin on a face peels back easily. He attached three sutures to the inside corner of Kevin’s mouth and gently pulled, to gauge exactly where the muscle should be attached.
“So you know it’s in the right place,” explains Nguyen. “If you don’t get this right, they’re going to have to live with it for the rest of their life.”
The moment Nguyen put strain on the triple surgical thread was the first time Kevin Portillo ever smiled on the left side of his face.
That done, Nguyen removed a 12-centimeter segment of gracilis muscle, along with a section of artery and vein, from the inside of Kevin’s left thigh, as well as the obturator nerve. The muscle was secured in place by a customized splint that hooked into Kevin’s mouth and was sewn to the side of his head to keep the relocated muscle from pulling out before it healed.
The section was taken from Kevin’s thigh because the powerful upper leg is rich in muscles. “There are so many muscles that do the same function . . . you don’t miss this,” Nguyen says.
Well… most wouldn’t miss it. Kevin, a diehard young soccer fan, did. “When the surgery came I couldn’t play,” he says. “I didn’t know it would take that long. I thought it would take a couple days and I would be back.”
Just how long was he sidelined?
“It was more than two weeks,” he says, sorrowfully.
“He wasn’t concerned with how serious the surgery was,” his mother says, laughing. “He was more concerned with not being able to play soccer.”
Over the next year, Kevin began to get motion on the left side of his mouth.
“It’s really kind of a magical thing,” says Nguyen. “We do this procedure, a number of hours and effort, using not a small amount of resources. We don’t know if it works or not.
“I saw him post-operatively within the first couple of weeks, he looked like he had this big bulgy thing in his cheek. Nothing was moving. All of a sudden, he was smiling. It was a really incredible moment.”
Well, it’s magical, but it’s also hard work. Low-tech and high-tech.
Kevin begins his regular occupational therapy session by holding a two-cent white plastic fork in his mouth and showing that he can move it up and down.
“Try to purse your lips together to make it stand up,” says Anne-Ashley Field, his therapist at CHoP. “We’ve got it pretty solid in the middle. Try to work it over to the weaker side. Nice try . . . and that’s harder.”
Kevin puts on purple latex gloves and pulls at the inside of his cheek.
“You’re going to do your stretch on the inside,” says Field. “A nice, slow hold. Good. Bring that thumb up . . . Do you feel like it’s getting looser than it was?”
“Mmm-hmmm,” Kevin agrees, gloved fingers in mouth.
She takes some photos. There is a lot of photography in facial therapy, to track progress.
“Now give me the biggest open-mouthed smile you can,” says Field. “Good. Can you make the left side go up even more? Try to make your gums even.”
Then, after more exercises, she asks if he is ready for the computer work.
They move into the next room, to a $20,000 Lenovo biometric therapy system. Field sticks a surface EMG–an oblong black sensor that reads electrical activity in the muscle–to Kevin’s left cheek and he plays a video game, Load Ship, where he moves animated boxes from a conveyor on the screen by smiling and relaxing.
“Give me a big smile,” Field says, calibrating the device. “And relax.”
He plays for four minutes, the game burbling a skittery kind of jazzy electronic music.
They play a few other games–one trying to get a man to a safe spot as two serrated blue spaces come together. Then a marble maze.
“How are you feeling?” she asks.
“Hurts,” he replies.
Physical rehabilitation is the part of the surgical process that often gets overlooked, but it can make the difference between success and failure.
“It’s huge, particularly with facial palsy,” says Nguyen. “You can do technically very sound surgery on two completely different patients and have two completely different outcomes based on how involved they are with their own therapy . . . It just doesn’t look as good.”
How does Kevin feel about being able to fully smile after a lifetime of not being able to?
“I’ve been getting better on how I react. I do it automatically,” says Kevin. “Sometimes when somebody says a joke. It actually feels great now. Before it felt weird to not smile. Smiling with both sides of my mouth at same time, I feel I’m one of the other people who smiles right.”
His mother remembers the moment she noticed.
“We were at the table, we were eating,” says Silvia. “And then we said, ‘Kevin, are you moving there?’ He started moving. Not the way he was doing today; little movements.”
“We were eating,” he says. “I think she said something funny, and I just smiled.”
And how does smiling affect his life?
“Before, I was actually shy,” he says. “Right now, I’m less shy, more active.”
“I used to have trouble expressing my emotions. Now people know if I’m smiling or laughing. When I laughed, before, I laughed weird. And right now, they know, bit by bit, that I was trying to smile, I was expressing my laughter and my smile. When I play soccer, and score a goal, I’m happy. I’m smiling, to tell everybody I scored.”
Wellcome Collection’s exhibition Teeth runs in London from 17 May to 16 September 2018.