When we hear a joke, see someone we love, or simply hear a few words that make us happy, we tend to do one simple action: smile. For most, it may not require much effort to turn our lips upward, but there is a science behind smiling. In fact, it takes 13 muscles to smile.
A smile starts in the sensory corridors, sending emotional data into the left anterior temporal region of the brain. Then, the data appears on the surface of the face, where two muscles manipulate the lips: the zygomatic major and the orbicular oculi. The zygomatic major is located in the cheek and turns the lips upward, while the orbicular oculi encircle the eye socket and squeeze the outside corners of our lips to resemble a crow’s foot. This process to produce a smile takes between two-thirds of a second to four seconds.
Since we use the zygomatic major and orbicular oculi muscles to smile, we can use the same muscles to determine a fake smile. When only the zygomatic major is activated, the smile is fake. The second muscle, the orbicular oculi, is an indicator that the smile is genuine as it shows creases around the eye socket. Our brains are able to easily distinguish between fake and real smiles by comparing the geometry of faces and thinking about situations to judge whether a smile is expected.
A genuine smile is scientifically referred to as the “Duchenne smile.” This name is a nod to Guillaume Duchenne, a French anatomist who studied emotional expression. Duchenne helped gather that the intensity of a true smile can predict personal well-being and longevity. On the other hand, a fake smile can reflect embarrassment, deceit, and grief.
Until the 1970s, many psychologists believed that smiles reflected an array of emotions, rather than being the expression of happiness. This belief was disproved by Paul Ekman and Wallace Friesen, psychologists at the University of California at San Francisco. Ekman and Friesen captured muscular coordinates behind 3,000 facial expressions, confirming that positive emotion was behind the true Duchenne smile. Duchenne smiles produced more activity in the brain’s left anterior region, which is correlated with positive emotions.
Smiling is a universal mechanism of communication. Scientist Andrew Newberg concluded that a smile is “the symbol rated with the highest positive emotional content.” When our facial muscles produce a smile, they create a positive feedback loop that goes back into our brains and creates a feeling of joy. Essentially, when our brain feels good and tells us to smile, we tell our brain it feels good and the loop continues.
Many people inherently smile more than others, despite possessing the same muscles. In 2003, Yale psychologist Marianna LaFrance performed an analysis of smiling research from 162 studies and a total of 100,000 participants. She was able to isolate three variables that influence smiling disparities between individuals. One of the variables was gender norms, in which different sexes tend to smile differently depending on whether they are being watched or not. Another variable was situational constraint. For instance, flight attendants are required to smile, whereas funeral directors must remain somber. This can cause a huge difference in the amount of smiling. Lastly, emotional climate plays a factor as embarrassing or tense situations tend to have females smile more than men.
Sometimes, life renders difficult, and a cause to genuinely smile seems bleak. However, one way to gain back a state of true happiness is to imagine a situation of joy that you previously experienced. This can be a conversation with someone you love or an event that gives you deep satisfaction. A strong memory can help trigger a smile. By smiling, you are scientifically contributing to your happiness!
