Spotting A Duchenne Smile: How To Identify A Genuine Smile

By Julia Thomas

Updated December 19, 2018

Reviewer Natalie Feinblatt


Nonverbal communication plays a big role in how we process interactions with others. Researchers tend to disagree on the actual numbers, but it is estimated between 60 to 93% of our communication is nonverbal. Whatever the number, it is clear nonverbal communication significantly impacts how we relate to others.

Smiling is one of the most powerful forms of nonverbal communication. A smile could start a relationship or disarm a hostile partner. It provides comfort and is often contagious. Smiling shares our joy and masks hidden agendas. On the surface, we associate smiling with happiness. Research has shown smiling is much more complex. While showing happiness, it could also convey embarrassment, self-doubt, deceit, arrogance, and even grief.

By understanding the physiology behind smiling, we can understand when this gesture is genuine and when it is more menacing.

What Is A Duchenne Smile?

Duchenne smiles are the true form of genuine smiles. This smile was named after a French neurologist Guillaume Duchenne de Boulogne, a pioneer of the science of electrophysiology. In his research, he discovered genuine smiles incorporated two specific facial muscles:

  • Zygomatic major muscle: This muscle resides around the cheeks and turns the corners of the lips up.
  • Orbicularis oculi muscle: This muscle contracts around the eyes resulting in the distinctive wrinkles often referred to as "crow's feet." It is also responsible for closing the eyelids.

A truly genuine smile requires both these muscles to work together. Other types of smiles only use the zygomatic major muscle. Duchenne argued only the "sweet emotions of the soul" force the orbicularis oculi to contract.

Duchenne's Research

Duchenne was fascinated with facial expressions and how people communicated using body language. In his research, he cataloged the muscles used for different facial expressions. He studied emotional expression by stimulating various facial muscles with electrical currents. Some of the experiments were so painful Duchenne needed to perform tests on the severed heads of executed criminals. He published a book in 1862 entitled Mecanisme de la Physionomie Humaine discussing his findings.

Much of his work was forgotten in modern times until Raul Ekman and Wallace Friesen, psychologists at the University of California at San Francisco in the 1970s, captured the muscular interactions of 3,000 facial expressions using their Facial Action Coding System (FACS). They found the Duchenne smile was associated with an increase in the brain's left anterior temporal region-an area connected with positive effect. Also, the activity of the left parietal region was increased-an area stimulated by verbal activity.

A renewed interest in Duchenne's work showed how positive emotions were directly correlated with genuine smiles. Some researchers believe the Duchenne smile is not just a brief spark of emotion, but a clear window into a person's core disposition.

Other Types Of Smiles

The Duchenne smile is just one type of smile. Some researchers suggest there are up to 50 different types of smiles we use to communicate. Smiles convey a variety of messages including fear, nervousness, deception, sarcasm, arrogance, concern-the list goes on. Aside from the Duchenne Smile here are some of the other common types of smiles:


Tight Lips Smile

The tight lips smile is one of the most common forms of smiling. It happens when the lips are stretched across the face, but there is very little upward curl at the corners of the mouth. Often no teeth are exposed. This smile is easily faked and used to smile politely. It is not genuine like the Duchenne smile. It could be used when nervous, reserved, uncertain, or even secretive. The tight lips smile is common when meeting someone new or communicating with someone you don't particularly like.

The Smug Smile

Similar to the tight lips smile, the smug smile usually has the lips pressed together-though not as tightly- or slightly separated. One corner of the mouth may be raised and the eyes often narrow. People associate the smug smile as a sign of arrogance, superiority, and satisfaction.

The Grin/Smirk

Very similar to the smug smile, but sending a slightly different message, is the grin. It's the expression that makes you want to say, "wipe that grin off your face." It can be used when questioning authority or when an arrogant, self-assured person is under direct verbal attack. Some people smirk when under stress while others may use it to ridicule.

The Uneven Or Half Smile

Like the grin, the uneven or half smile has lips together or slightly apart, but one side of the mouth is usually raised while the other side is level or lower. This smile is often associated with sarcasm or tongue-in-cheek humor. It is typically used when conflicting emotions are present such as happy and shy, sad and comforting, etc.

Seductive Smile

Smiles are very effective at showing our affection or interest for someone else. Anyone receiving a seductive smile from the desired love interest surely felt the excitement and a swarm of butterflies in the stomach. This is a slight smile often accompanied by other gestures like direct eye contact then quickly turning away.

Tips for Spotting A Fake Smile

By understanding the muscles involved in genuine smiles, it is much easier to tell when a person's smile is fake or forced. Spotting a fake smile can make us more mindful of another person's nonverbal communications and their true intentions. For example, you could tell just how interested a person may be by noticing their smile. Tight lip smiles could indicate the person is being polite, feigning interest, or unsure how they feel about you. When the person greets you with a Duchenne smile, you are assured this person has a genuine interest in you.

Here are three ways to spot a fake smile:


  • The absence of eye movements: Genuine smiles employ the orbicularis oculi muscle. This muscle causes the eyes to close. If a person is faking a smile, they will show no movements in the upper face.
  • The absence of crow's feet: As you know by now, the area around the eyes are a telltale sign of a genuine smile. The orbicularis oculi muscle is also responsible for crow's feet at the corners of the eyes. Once you see a smile, look around the eyes.
  • Visible bottom teeth: During a genuine smile the zygomatic major muscle moves upwards. When faking a smile, there is a tendency for this muscle to move outwards sometimes exposing the bottom teeth. Think of all the times you forced a smile by saying "cheese" for the camera. Be aware; not everyone will expose their bottom teeth, especially since there are so many types of fake smiles.

The Benefits Of Smiling

Genuine smiles are more than a sign of happiness. The benefits of smiling and the laughter that often follows can have a positive effect on your health and well-being. Here are a few of those benefits:

Smiling Releases Endorphins

The act of smiling triggers the release of neurotransmitters called endorphins. These chemicals help lower stress levels and make us feel happier. Endorphins also act as natural painkillers helping those with chronic pain. As we increase our smiling, more endorphins are released into our system helping us feel less tense and happier.

Boosting The Immune System

Smiling can help prevent and fight illnesses. When endorphins are released while smiling, cortisol-a stress hormone-is reduced. Cortisol is associated with high blood pressure, added body fat, a suppressed immune system, and even a reduced libido. Also, a study conducted on hospitalized children visited by storytellers and puppeteers showed an increase in immunity-boosting white blood cells an hour after the visit.

Smiles Are Contagious

It's not often you hear something contagious is good. Smiling is the exception. When you see someone smile, the area of your brain controlling facial movements is activated often leading to a smile or grin. Even intense or bad situations, a smile could be contagious and offer some relief.


Smiling Makes You More Attractive

When you smile, you appear more positive and approachable to others. Genuine smiles could convey self-confidence, a cheerful demeanor, and trustworthiness. Projecting these desirable traits with a genuine smile makes others more willing to engage socially with you. Don't be afraid to show that genuine smile with someone you've wanted to meet.

Duchenne Smiles Increase As A Person Undergoes Therapy Or Treatment

When a person gets help for mental health issues causing them distress, genuine smiles become more frequent. For example, patients treated for depression had more instances of Duchenne smiles during their discharge interviews compared to admissions into treatment. Duchenne smiling, and not other types of smiles, were found to increase over the course of psychotherapy. This indicates effective psychotherapy can play a role in a person finding the "sweetness of the soul," as Duchenne put it.

Getting help from a psychotherapist is the first brave step creating positive change in your life. For many, a traditional therapy setting may be inconvenient or cost-prohibitive. Luckily, technology has made it easier to get the help you need. Online licensed and accredited psychotherapists provide a convenient and affordable option for treating a variety of mental health issues. takes pride in giving their clients quality psychotherapy without all the hassles of a traditional therapy setting. If you are struggling with any issues, let the caring professionals at help you show your best Duchenne smiles to the world.


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