The results are astonishing. In a smile-impoverished environment, the young child no longer explores the environment, no longer approaches novel toys or play structures; her imagination shuts down. The child quickly becomes agitated and distressed, often wildly so, arching his or her back and crying out. The child will often move to the mother and try to provoke her, stir her out of her stupor, with a vocalization or touch or encouraging smile. And as the child begins to resign herself to the unexpressive condition of the mother, she moves away from the mother, refusing eye contact, and eventually falls into listlessness and torpor.
The same is true, albeit on a much smaller scale, with adults. Friends of depressives find their interactions, research shows, to be unrewarding, and at times difficult to sustain. In conversations with individuals who show little positive emotion in the face or voice, participants engage in less responsive social behavior—playful laughs, smiles, head nods, knowing mutual gazes—and experience the conversations as unrewarding.
The smiles, and I should say D smiles, which punctuate our daily interactions—between parents and children, flirting strangers, friends sharing a silent moment of satirical commentary upon an acquaintance—are like social chocolate. With chocolate waiting to be enjoyed, young children, and a good many adults, will do just about anything with verve—mow through that side of vegetables, clean hamster cages, listen to long-winded adult stories, finish an odious task at work. The same is true of smiles; they are the first incentives toward which young children move, and that parents hungrily seek. In relevant research, when one-year-old infants sit at the edge of a visual cliff, a glass surface over a precipitous drop, with their mother on the other side, the infant immediately looks to the mother for information about this ambiguous scene, which looks both dangerous and passable. If the mother shows fear, not a single child will crawl across the glass surface. If the mother smiles, my Berkeley colleague Joe Campos finds, approximately 80 percent of the infants will eagerly cross the surface, risking potential harm, to be in the warm, reassuring midst of their mother’s smile.
From the standpoint of the person smiling, we know from elegant work by Barbara Fredrickson and Robert Levenson that when people emit D smiles when experiencing stress, their level of cardiovascular arousal quickly moves to a more quiescent baseline. My hunch is that, as Darwin observed, with the D smile the individual exhales strongly, which calms stress-related physiology. We have also already seen that in the midst of a D smile, the smiler’s left portion of the frontal lobes—a region of the brain that processes information about rewards and enables goal-directed action—is activated.
Perhaps more dramatic is what the smile does to the person perceiving it. The definitive work on this topic has been done by Ulf Dimberg and Arne Öhman, working in labs in Norway and Sweden, respectively. These investigators have pioneered techniques for presenting images of facial expressions to perceivers at incredibly fast speeds, outside of the perceivers’ conscious awareness. Most typically, in what is known as the backward masking paradigm, they present slides of facial expressions (for example, facial displays of anger or the smile) for exceptionally brief periods—say, 100 milliseconds. Immediately following the image of the smile, another image is presented—say, of a neutral face, or a chair—which wipes out the participant’s ability to consciously represent the image of the smile. In the backward masking paradigm, participants cannot tell you with any reliability what first image they have just seen; the smile (or comparison facial display) has only been perceived at the unconscious level. And yet people who have viewed smiles in this fashion are more likely to smile and report greater contentment and well-being, and in some studies, they show calmer cardiovascular physiology. They have no idea what they have just seen, but the smile has enhanced their well-being.
It goes deeper than this. Richard Depue and Jeannine Morrone-Strupinsky suggest that perceiving smiles in others, most likely of the Duchenne variety, triggers the release of the neurotransmitter dopamine, which facilitates friendly approach and affiliation. As one illustration, dopamine is activated in heterosexual males by viewing the smiles of attractive females. Smiles catapult individuals toward one another, and in the more intimate space produced by mutual smiles a more proximal set of behaviors—touch and soothing vocalizations—kick into action, soothing, calming, and triggering the release of opiates, which bring about powerful feelings of warmth, calmness, and intimacy.
When you see the exchange of D smiles between a father and a toddler on a swing, between two adults flirting in the corner of a room, between two friends laughing over their latest efforts at work or romance, or between two strangers navigating who goes through the door first or who takes the last egg roll at the buffet—one cannot help but be struck by the simplicity of social pleasure. Two smiles are exchanged within the span of a second or two, this small but universal element of decorum is honored, and the day continues. Within the bodies of those individuals, however, are reciprocally coordinated surges of dopamine and the opiates. Stress-related cardiovascular response reduces. A sense of trust and social well-being rises. The smile is the dessert of our social lives. It evolved as a neon-light signal of cooperativeness, it became embedded in social exchanges between individuals that give rise to closeness and affiliation. The right kind of smile is a common contributor to the numerator of the jen ratio and a gateway to the life well lived. And this was the hypothesis I tested in an unusual study of yearbook photos of graduates from a small women’s college in 1960, just about to head out into a world that would turn tumultuous.
FLEETING MOMENTS OF THE COURSE OF LIFE
Ravenna Helson is a pioneer in the study of women’s lives. In the early stages of her scientific career in the 1950s, she was interested in the intellectual creativity of women—an area almost entirely ignored by psychological science—and interviewed female pioneers in mathematics and the physical sciences. She then turned her scientific imagination to the question of how identity develops. Almost all of the longitudinal research on identity and the course of life had been done on men; the lifespan development of the other half of the species was a mystery. In 1959, a few years prior to publication of Betty Friedan’s The Feminine Mystique, Ravenna initiated what would become the longest longitudinal study of the lives of women ever conducted, the Mills Longitudinal Study. This study has followed the lives of approximately 110 women who graduated from Mills College in 1959 and 1960 for the past fifty years, and continues to this day. It has led to basic discoveries about how identity shifts over the course of life for women, and how it remains the same.
In 1999 Ravenna stopped by my office with a generous offer. She noted, in her slight Texas drawl and gentle style, that she had gathered college yearbook photos of her subjects. She wondered whether I might be interested, with a student of hers, LeeAnne Harker, in exploring whether her Mills participants’ smiles, captured when they were graduating from college, would say anything about the next thirty years of their lives. The more conventional side to my scientific mind predisposed me to politely decline. The premise that expressive behavior gathered in one instant in time (in the few milliseconds it takes for the shutter to open) in such an artificial context (having your yearbook photo taken by a stranger) could actually predict anything meaningful about an individual’s life violated the most sacred laws of studying individuals scientifically. Within the study of individuals, it is canonical to sample a person’s behavior many times and in a diverse and revealing array of contexts. A more representative sampling of observations guarantees more reliable inferences about who the person is. If you want to know whom to marry or what friend to travel with, you’re best served by seeing them when grumpy in the morning after a bad night’s sleep, when handling the stress of a conflict, when experiencing pain, around their mothers and ex-spouses, and when things go really well, and not just when sparkling in witty repartee at a cocktail party. Relying upon one yearbook photo as a potential measure of the person’s identity was problematic in this regard, to say the least.