Smiling in humans is somewhat akin to dogs wagging their tails as smiling is a key part of human communication. IFOD on why Dogs Have Tails. Below are some very interesting facts about smiling:

There Might Be As Many As 19 Types of Smiles

While the exact number of types of smiles is debated, there are quite a few types and some experts claim there are 19 of them. Here are some of the most recognized ones:

• Duchenne Smile: This is considered the true smile of happiness and enjoyment and is named for French anatomist Guillaume Duchenne.  According to the Association for Psychological Science, the Duchenne Smile occurs when “the zygomatic major, which resides in the cheek, tugs the lips upward, and the orbicularis oculi, which encircles the eye socket, squeezes the outside corners into the shape of a crow’s foot.” You know this one – its a true, genuine smile.
• Fear Smile: While we don’t usually associate smiling with fear, it is not uncommon to smile when feeling fear or distress. 
• Miserable Smile: This is a “grin-and-bear-it” expression and is the type of smile you see when people are just trying to get through their current, unpleasant experience. A study of Olympic athletes during medal ceremonies found this was a common smile while receiving a silver medal.
• Dampened Smile: This type of smile typically shows no teeth and is often the result of trying to suppress a genuine smile, often in response to etiquette or social norms.
• Embarrassed Smile: Embarrassment can produce all sorts of expressions – blushing, looking downward, covering ones face. It also is commonly accompanied with a shy smile.
• Uncomfortable Smile: This is a smile often in response to something inappropriate. A study to this effect asked women inappropriate sexual questions during a “job interview” and videotaped their reactions. The most common facial expression in response to the questions was a strained, uncomfortable smile. (Note that the study also found that men often then misinterpreted these smiles as genuine and not as a cue of displeasure.)
• Seductive Smile: This is my most common smile. (JK.) According to  resarcher Ronald Riggio, “when people try to be seductive, they typically display positive affect – a slight smile that accompanies direct eye contact, with a slow glance away, but still holding the smile.  Interestingly, the seductive smile could be accompanied by submissive behavior (tilting the head downward), or dominant behavior – proudly and slowly glancing away.”
• Sarcastic Smile: This is a smile of enjoyment mixed with disdain or dislike.
• Fake Smile: This occurs when attempting to force a Duchenne smile of happiness. However, it is really hard to successfully fake a Duchenne smile. Here’s an explanation from the book Adaptive Markets by Andrew W. Lo of MIT: “Most of us can easily detect the difference between a natural smile and a forced smile. How? The answer lies in the way the brain is organized. A natural smile is generated by one region of the brain—the anterior cingulate cortex—and it involves certain involuntary facial muscles that are not under conscious motor control. A forced smile, however, is a purely voluntary behavior originating from the motor cortex of the brain. It’s not the same as a genuine smile, because the involuntary muscles of the face don’t participate; those muscles stay the way they were, giving the person’s expression a frozen, painted-on look. “

Benefits of Smiling

Smiling has a lot of benefits and each time you smile, whether real or fake, you light up a chemical party in your brain as endorphins, dopamine and serotonin is released. Your mood is elevated, your heart rate is reduced and the production of the stress cortisol is reduced. Here are some other interesting benefits of smiling:

• We often smile when happy. The converse can also be true: smiling can increase our happiness and can reduce stress. Try it – force a smile right now. Notice how you feel. Great quote to this effect: 
  “Sometimes your joy is the source of your smile, but sometimes your smile can be the source of your joy.” —Thich Nhat Hanh
• Studies have found that smiling makes you look more attractive and healthier.
• Smiling and/or frowning less has been shown to reduce the effects of depression. This interesting study used botox or a placebo to reduce frowning (or not) in volunteers with major depression and found that botox treated people reported less depression than those injected with just saline.
• Smiling can be contagious. From Psychology Today:  “In a Swedish study, subjects were shown pictures of several emotions: joy, anger, fear, and surprise. When the picture of someone smiling was presented, the researchers asked the subjects to frown. Instead, they found that the facial expressions went directly to imitation of what subjects saw. It took conscious effort to turn that smile upside-down. So if you’re smiling at someone, it’s likely they can’t help but smile back. If they don’t, they’re making a conscious effort not to.
  Each time you smile at a person, their brain coaxes them to return the favor. You are creating a symbiotic relationship that allows both of you to release feel-good chemicals in your brain, activate reward centers, make you both more attractive, and increase the chances of you both living longer, healthier lives. ” Thus, if you smile at someone you are likely increasing their overall happiness and health!

I am going to make a conscious effort to smile more today. Have a nice Friday!