Parsimonious and pleasing as this may be, it’s wrong. When primatologist Signe Preuschoft put Darwin’s smile-as-laughter thesis to the test by examining when various nonhuman primates show smilelike and laughterlike displays, she found that these two displays occur in much different social contexts, and toward much different ends. The smile and the laugh originate in distinct slices of early primate life, and have subsequently followed separate evolutionary trajectories as they worked their way into the human emotional repertoire and our nervous systems.
SILENT BARED-TEETH AND RELAXED OPEN-MOUTH DISPLAYS
In her careful observations of primates, in particular several different macaque species, Preuschoft has catalogued numerous displays that convey affiliative, cooperative intent. These include pout faces and lip smacks (which Darwin wrote about—see chapter 2)—no doubt predecessors to the succor-seeking sulking we see in three-year-olds, and of course, the kiss. The most common affiliation-seeking displays in primates, and most central to our understanding of human smiling and laughter, are the silent bared-teeth display and the relaxed open-mouth display.
Across species, primates resort to the silent bared-teeth display to appease and to signal submissiveness, weakness, and social fear in contexts in which the likelihood of conflict and aggression is high, for example when nearing dominant primates. The silent bared-teeth display is most typically seen in submissive primates and is usually accompanied by inhibited posture, protective body movements such as shoulder and neck tightening, or hands hovering around the face for obvious defensive purposes. Thankfully, this display often short-circuits aggression, triggering reconciliation in the dominant monkey—affiliative grooming and embracing.
In humans, the silent bared-teeth display is evident in our deferential smile, which signals thoughtful, at times fearful, attention to the concerns of others. This smile involves the activity of two muscles: the zygomatic major, which pulls the lip corners upward, and the risorius, which pulls the lower lip sideways. I first encountered the deferential smile empirically in an early study of teasing, in which I had two high-and two low-status fraternity brothers tease one another. As they ripped into each other in the profane gutter language of young men living together in tight quarters, the low-status guys were ten times more likely to show deferential smiles. A good time was had by all, but it was the low-status guys who signaled their subordinate positions with this smile.
The relaxed open-mouth display, in contrast, is observed, Preuschoft notes, in fewer primate species. It is accompanied by panting and staccato breathing, and on occasion bursts of grunt-or howl-like vocalizations and boisterous body movements. Quite clearly, the relaxed open-mouth display is the primate predecessor to the human laugh. Importantly, Preuschoft has found that the relaxed open-mouth display occurs in a radically different set of social contexts than those associated with the silent bared-teeth display: It precedes and accompanies the pyrotechnics of primate play—chasing, nuzzling, gnawing, rough-and-tumble somersaults and cavorting in the branches of trees.
Preuschoft’s analysis of these two primate displays makes it difficult, even for the ardently faithful, to continue entertaining Darwin’s hypothesis that the smile is the first stage of the laugh. No longer tenable as well is the pleasing inference that our capacity for play is the most rudimentary element of positive emotion. Instead, we must conclude that smiling and laughter have distinct evolutionary origins. The smile emerged to facilitate cooperative and affiliative proximity. The laugh emerged to promote play and levity. They are tokens of different swaths of positive emotion, and different facets of the meaningful life.
A VOCABULARY OF SMILES
During the summer following my freshman year in college, I decided to teach myself classical guitar while living at home in Penryn, California, a tiny rural backwater named after an island in Wales. Two weeks into thick-fingered attempts at “Classical Gas,” my mother had had enough. A week later I found myself donning the brown polyester and golden arches insignia of the McDonald’s uniform, serving burgers, fries, Chicken McNuggets, and gooey sundaes to sunburned revelers on their way to underaged drinking and debauchery at the rocky rivers in the foothills of the Sierras or the noisy waterskiing lakes. Each and every day at 11:10 AM a middle-aged man arrived, strode to the counter in shoes that made a strange clicking sound, and, with somber brown eyes and Lincolnesque sideburns, placed the same order: four plain hamburgers, with nothing on the gray patties and buns that dissolved upon touch, and a cup of black coffee, which I had to refill a dozen or so times in the span of the thirty-six minutes he reliably took to finish his lunch. He became a Sisyphus-like commentary on my fate: the minimum-wage undermining of my musical career and the missed opportunities for summertime revelry. My manager, a good-hearted, optimistic soul, recognized my deep despair and offered managerial guidance straight out of some McDonald’s handbook: just smile. I felt deeply oppressed, filling the regular customer’s Styrofoam cup with another round of coffee, smiling as I delivered his cup of joe.
I can assure you that I was not smiling the smile that evolution has produced, and which we will soon dissect, and which promotes goodwill between individuals. Much more likely, I was emitting the service industry smile, the one that signals that the customer is always right, that the sale should always come first. Sociologist Arlie Hochschild has argued that this smile is part of the emotional labor required of so many service-oriented jobs and the tip of the iceberg of alienation from the fruits of human labor. Research shows that when workers smile in the service industry, for example when greeting customers at a 7-11 counter, customers are more satisfied and actually more likely to consume. As the bottom line is enhanced, however, workers experience a problematic disconnect, Hochschild argues, between the emotions they display to the outer world and the feelings they experience within. This disconnect has parallels to recent studies by my colleague Ann Kring of schizophrenics. Contrary to longstanding assumptions about schizophrenia and flat affect, schizophrenics have been shown to feel the emotions that you and I feel but not to express them in the face. Service industry jobs produce a form of schizophrenia: We may experience feelings of emptiness and quiet frustration, or a deep ennui, but we display to the world the smile of satisfaction.
How then can we provide a coherent analysis of a category of behaviors—smiles—that includes my McD smile as well as the loving smiles of old friends and parents and children? At first glance, the empirical literature on the smile yields similarly paradoxical findings: People have been shown to smile when winning, losing, watching a film of an amputation, eating sweets, facing adversaries, experiencing pain, feeling affection toward loved ones. The answer is provided by Paul Ekman, and it involves looking away from the lip corners to that wellspring of the soul—the eyes.
A vocabulary of smiles comes sharply into focus when we consider the activity of the happiness muscle, the orbicularis oculi. This muscle surrounds the eyes and when contracted leads to the raising of the cheek, the pouching of the lower eyelid, and the appearance of those dreaded crow’s-feet—the most visible sign of happiness—which the Botox industry is trying to wipe out of the vocabulary of human expression. People may think they look prettier following Botox injections, but their partners will receive fewer clues to their joy, love, and devotion.
Ekman has called smiles that involve the activation of the zygomatic major muscle and the orbicularis oculi the Duchenne or D smile, in honor of the French neuroanatomist Guillaume Benjamin Amand Duchenne (1806–1875), who first discovered the visible traces of the activity of orbicularis oculi. Smiles that do not involve the activity of the happiness muscle, the orbicularis oculi, are sensibly known as non-Duchenne or non-D smiles. To try your hand at this subtle distinction between Duchenne and non-Duchenne smiles, see if you can detect which is which in the photographs below (answers provided on chapter 6).