Do you ever catch yourself smiling inwardly or outwardly when you type a colon and a closed parenthesis that magically turns in to a happy face on your computer? I do. It’s funny how a tiny little emoji on my computer screen has this power.

Friday is World Smile Day, a day that deserves attention — here’s why.

There’s science that backs the power of smiling. Smiling is like a stimulant — it triggers the brain chemistry just as chocolate does. A smile reduces stress hormones, increases happy hormones and lowers blood pressure. When you smile, serotonin, dopamine and endorphins throw a party in your brain.

We’re hard-wired to smile. Babies in the womb appear to smile. Even blind babies smile in response to the sound of the human voice. It’s a cross-cultural phenomenon that’s contagious. In fact, don’t you find it nearly impossible not to smile back when someone smiles at you?

So many studies have been conducted worldwide on the smile phenomenon. In one study, researchers used chopsticks to manipulate the facial muscles of 169 participants into either a neutral expression or a smile. A third group was instructed to smile without chopstick manipulation.

Participants endured a series of stressful, multitasking activities while their faces were held in place. Heart rates were monitored and participants reported about their stress levels. Smiling participants showed lower heart rates than those with neutral expressions. Those with the biggest smiles were the most relaxed.

If that’s not enough to put a smile on your face, the expression makes us more attractive to others. A Penn State University study confirmed that when we smile we not only appear more likeable and courteous, but we’re actually thought to be more competent.

So what if you’re not the “smiling” type? In ancient China, Taoists taught followers to have an inner smile. Mantak Chia, a Taoist Master said having a constant inner smile, which is simply a smile to oneself — ensured health, happiness and longevity. Why? Because smiling to yourself is like basking in love.

Lightly close your mouth, exhale through your nose and then bring the corners of your mouth up slightly. Feel your eyes soften and you’ll feel a sense of relaxation. Do this often.

So this Aloha Friday celebrate World Smile Day by conducting your own mindful experiment. Smile inwardly or outwardly through the day and see if it impacts your outlook.

Zen Master Thich Nhat Hanh said, “Sometimes your joy is the source of your smile, but sometimes your smile can be the source of your joy.”