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Why Do We Smile?
May 22, 2024

Woman with a big smile.

As your dentist, we are dedicated to keeping your smile healthy. But what is a smile, and why do we do it? You probably smile dozens and dozens of times per day, and children smile an average of 400 times a day, but you probably never even think about it.

Let’s find out more about the happy, and surprisingly important, smile.

What is a Smile?

We all know what a smile looks like, of course, but what is happening when we smile? Facial expressions, like smiles, are extremely important forms of expression for human beings. They help us in communicating with others, and as social beings, this is highly important.

We use facial expressions both reflexively (meaning, without thinking about it) or on purpose, but more on that later. Some are believed to be completely instinctual, while others can be socially conditioned.

How We Smile

Facial expressions, like a smile, are controlled by the muscles beneath the skin of the face. Different combinations of flexing or relaxing various muscles result in a range of such expressions. In face, relaxing muscles can be just as important as engaging them when it comes to expressions. What we see when we view a smile is not just the muscles of the face but also the bones they move.

Facial muscles are controlled with signals from the seventh cranial nerve (a.k.a. the facial nerve). The face has a total of 43 muscles, and most important muscle involved in a smile is the zygomaticus major, a muscle in the front of the face that lies below the cheekbones. This is the muscle responsible for raising the corners of your mouth when you smile. However, there are other muscles involved in smiling, with a slight smile using only 5 pairs of muscles and a big grin using twice that.

What about that old adage that it takes more muscles to frown than to smile? Well, that may be a myth. In fact, we can’t necessarily be sure which takes more since every person’s anatomy differs, and the range of these expressions is almost infinite.

The Why Behind Your Smile

Now that you have an idea of how we smile let’s get to the “why?” As we mentioned, it mostly comes down to communication. We can thank evolution for many things, including facial expressions. In fact, smiling is an innate behavior. A person who is born blind may never see a smile, but she will smile just like someone who is sighted.

Interestingly, when most species show teeth, it is a sign of aggression. But for humans, a smile is typically associated with positive emotions. That is because facial expressions are more subtle in us and other primates than simply baring teeth or not. In many primates, if lips are curled back and teeth are apart, that is a bad sign. But when the teeth are together, and the lips relaxed, it has the opposite implication. Some argue that this comes from expressions in our evolutionary ancestors that indicated submission or a lack of threat.

Nowadays, smiling is associated with a range of circumstances, from delight to humor to showing humility with self-deprecation (a nod to a smile’s potential roots). In addition, smiling doesn’t only help us express our emotions to others; it can also have an effect on the smiler.

Expression of Emotion

The most commonly thought of meaning of a smile is to convey happiness. We smile reflexively when we are feeling emotions from contentment to joy.


When we smile at others we are communicating with them even without words. A smile can indicate you are friendly and put someone else at ease. It is a social tool for understanding our environment and the tone of an exchange with another person.

Responding to an Awkward Situation

You have probably heard of a nervous smile. We also smile to defuse tense situations or “lighten up” a negative mood.

Benefits of a Smile

While a smile can have positive benefits for those viewing it, it also benefits the person smiling. Smiling can improve your mood by boosting feel-good neurochemicals and dampening those that cause stress, pain, and negative emotions.

We hope we made you smile! And now that you know why we smile, don’t forget to take great care of yours. Call us to book your next dental appointment now!

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