By Doug Gillett

Supposedly it takes fewer muscles to smile than to frown, but Sara Petrov might take issue with any suggestion that smiling is easy. When Petrov, a member of UAB’s synchronized-swimming team, hits the pool, she’s in for three to four of the most physically demanding minutes a person can endure. And on top of executing acrobatic moves and controlling her breathing while kicking furiously to maintain her position in the water, she has to keep a brilliant smile plastered on her face—because the judges will notice if it falters even for an instant.

A lot of elements are involved in the “perfect smile,” and a smile can mask a lot of things and send a lot of signals. The smile may be the most basic indicator of human happiness, but there’s nothing simple about it.

Virginia Peck Richmond, Ph.D., UAB’s chair of communication studies, says that anywhere from 60 to 90 percent of our communication carries some kind of nonverbal component. “Smiling is generally considered one of the most significant displays that a human being can use,” she says. “Doors open to people who smile. People listen to people who smile.” Yet a smile can also convey messages beyond what we intend, Richmond notes. “Based on a single smile, people will make assumptions that may or may not be correct in terms of happiness, affiliation, love, and even intimacy.”

Interpreting facial expressions can be particularly challenging when people have facial abnormalities or crooked features, says Peter Waite, M.D., an oral/maxillofacial surgeon at the School of Dentistry who has operated on patients with a variety of problems—from major deformities to features that might only be off by a couple of millimeters. “A lot of times patients come to me and say, ‘Everybody thinks I’m mad—that I’m always frowning or pouting,’” he says. “And after surgery, they look happier.”

Waite says there are certain aspects of a smile that are considered almost universally beautiful: The lower lip should follow the incisal edge of the teeth, while the upper lip should follow the gingival margin, the line where teeth and gums meet. “If someone smiles too much and shows too much gum, and their upper lip doesn’t follow that crease, we may view it as unnatural,” he says. A few millimeters, he adds, can make all the difference.

According to Richmond, the work of renowned anthropologist Desmond Morris corroborates the idea that symmetry and proportion have a profound effect on how a smile is interpreted. “He even notes that a smile that shows some teeth is perceived as more friendly than a smile that does not,” she says. “This goes back hundreds of years to when many humans would hide weapons in their mouths or have their teeth chiseled into weapons.”

No wonder, then, that the task of smiling the “perfect smile” is a lot harder than we think. But Sara Petrov says smiling during synchronized-swimming performances eventually becomes as much a part of the training regimen as any other skill. “During practice it’s like anything else,” she says. “You work on that part of your performance; you work on the skills that are necessary to swim at a high level, and smiling is one of them. You feel awkward, you look like the biggest idiot, but it forms a habit.”
Why is it so important for synchronized swimmers to keep that grin in place? “The smile is used to mask effort: If you’re smiling, it looks easy,” says Petrov. “Think about what runners look like when they run—if we didn’t smile, it would look like that.”

Deidre Downs, who won the title of Miss America in 2004 and is now in her first year of medical school at UAB, can recall plenty of days when a brilliant “stage smile” was hard to muster. But often the very same things that made the pageant grind so demanding were also the things that brought a smile to her face.

“I had my picture taken hundreds or even thousands of times when I traveled and went to events, and sometimes it was hard to smile if I was really tired or had had a strenuous day or things were going on in my personal life,” she says. “But I’m a real people person, so just interacting with people was enough to get me back out of that bad mood and make me smile, because I like to joke around with people and make life fun. When there are people around and things to laugh about, I’m happy.”