You catch a smile from someone, and it somehow conveys more than just simple charm. It’s warm, it’s inviting. It feels genuine, as though it’s conveying true happiness. This smile does not feel like every other smile because, well, it is not every other smile! Not every smile is created equal, but what then, makes these smiles so special?
The smile described above is likely a “Duchenne smile.” Named after 19th-century French anatomist G.B. Duchenne, these smiles use distinctive facial muscles. We often think of smiles as the upturning of one’s lips, but a Duchenne smile is that, and much more. A Duchenne smile also involves a pulling up of the cheeks, a squinting of the eyes, and perhaps, the appearance of crow’s feet.
Now, as many of us can attest to, a “regular” smile can be deliberately used to convey different emotions such as a pleasantry or underlying slyness. It offers us utility and diversity in expression, and in that way, it is important to have it easily on hand. This also makes the emotional content of “regular” smiles particularly hard to identify. This was especially salient before COVID-19 vaccines were widely available, as a majority of us had our mouths covered in public, effectively relegating the “regular” smile to undetectable.
The same cannot be said of a Duchenne smile. While Duchenne smiles can be done on purpose by many people, their interpretation is less diverse. Duchenne smiles are more likely to convey a singular message: “I’m happy” or at least are often perceived as more genuine and happier than regular smiles. They are interpreted as a more honest message about emotions, where a regular smile might not be. That is part of what makes these smiles so appealing, but perhaps there’s more to it than just that.
Frequent Duchenne smiling may also be a sign chronic positive mood. While one Duchenne smile may indicate a happy moment in one’s life, a collection of Duchenne smiles over a period may indicate a general happy feeling over that period. Chronic positive mood confers benefits in social and health domains, and as such can serve as a sign of one’s psychological fitness.
My collaborators and I ran a preliminary test of this idea in a recent study. In this study, participants self-reported their well-being and submitted photos of themselves. Photos were then standardized to show only participants’ faces, yielding 162 faces with varying smiling intensity and associated self-reports of felt well-being.
Research assistants then rated each of these photos for “overall happiness,” “genuineness of the smile,” “smiling in the mouth,” and “smiling in the eyes.” Genuineness of the smiles, intensity of the smile in the mouth area, and intensity of the smile in the eyes area were all associated with participants’ self-reported positive moods. The more positive participants’ moods, the more research assistants perceived the smiles in their pictures as genuine and intense in the mouth and eyes. This finding supports the idea that perceptions of smiles may be a reliable indicator of underlying felt moods, specifically happiness and chronic positive mood.
Happiness in the Moment versus a Life that Makes Happiness
When discussing “happiness,” a clear distinction must be made. Happiness is an emotional state that can be transitory, but a person may also live a life that is generally happy. This is something the ancient Greeks talked about. They talked about living life to the “highest human good” and achieving virtue through action, which in turn will produce happiness. Thus, the momentary state of happiness is not the same as a way of living.
How does this fit with our understanding of Duchenne smiling? Perhaps, the Duchenne smile serves multiple purposes. For one, frequent Duchenne smiles may be interpreted as a sign of the person’s chronic positive mood. Secondly, given that chronic positive mood is in part predicted by living a virtuous, and rewarding life, Duchenne smiles may be an indicator of underlying life patterns. In other words, “living good” leads to “feeling good.” A person who lives such a life is more likely to engage in activities that bring them happiness, and thus might exhibit a happier demeanor and perhaps a greater number of Duchenne smiles.
Therefore, a happy demeanor and Duchenne smiles might serve as a sign of a good person, and thus a person whom we would want to affiliate and cooperate with. Thus, Duchenne smiles may have served and perhaps continue to serve an evolutionary purpose. Duchenne smiles could be a nonverbal sign that cooperating with this person could be rather fruitful given that they lead a “good” life.
Back to the question that we started with: What is in a smile? It turns out much more than you may have considered. A Duchenne smile is likely to convey real feelings of joy, it perhaps means that this person often feels positive moods and is someone you want to work with. So, the next time you see a smile that warms your heart, you know that it may be for good reason.
For Further Reading
Sheldon, K. M., Corcoran, M., & Sheldon, M. (2021). Duchenne smiles as honest signals of chronic positive mood. Perspectives on Psychological Science, doi.org/10.1177/1745691620959831
Mike Corcoran is an Assistant Professor of Psychology at Cabrini University. He studies well-being, goals, and motivation.
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