The message of this day exhorts us to: "Do an act of kindness. Help one person smile!" Accordingly, the website www.worldsmileday.com asks that everyone is an Ambassador for the day - and that we all "make spreading smiles and kind acts part of our daily routine".
Harvey, who died in 2001, was the creator of the Smiley Face in 1963. The fact that this image has become possibly the most recognisable symbol of good will and good cheer on the planet, actually bothered Harvey. He felt the symbol had lost meaning because of the sheer repetition of the market place. Hence the creation of World Smile Day - and a determination to make good will and good cheer more than a ritual emoticon.
We take lots of things for granted - but when we stop and analyse a piece of body language as common as the smile, it's curious how much there is to know.
We understand the smile universally as an expression of pleasure, sociability and happiness. The simple act of flexing those muscles throughout the mouth is further transformed into a genuine smile - a Duchenne smile - by simultaneously contracting the little muscles in the corner of the eyes. A cascade of results are likely to follow - below are just some of them:
You'll experience a reduction in stress:
A smile will activate neuropeptides that work towards fighting off stress. This will reduce cortisol, - the stress hormone - and make you feel a lot more relaxed.
You'll feel happier:
The physical act of smiling triggers the happy chemicals of dopamine, endorphins and serotonin - and according to recent research, even if it is a fake smile, the brain will still receive the message that we are 'happy,' (even if we are actually nervous and stressed out). So capitalise on what is known as the 'facial feedback hypothesis', first described by Charles Darwin, and trick your body the next time you are feeling down.
Pain is reduced:
A result of the natural painkilling properties of endorphins, which are released by smiling and laughing - and yet another bonus is that heart rate and blood pressure are lowered by endorphins as well.
You'll look more attractive:
A Scottish study in 2011 at Face Research Laboratory has shown that men and women are more attracted to images of people who make eye contact and smile. If you appear approachable, then the chances of a happy interaction are increased - which will in turn have a positive impact on your wellbeing.
Your ability to flirt effectively will increase:
This is especially true for women, says psychologist Sam Owen, of Elite Singles dating site. More effective than flirty eye contact or the sultry pose, apparently.
You'll sound sweeter:
A smile with a verbal communication can suggest openness, trustworthiness and warm heartedness. Even on the phone, research studies suggest that the tone of voice spoken with a smile is likely to make the listener feel positive. If you make people feel relaxed and happy, they will come to associate you with these good feelings.
So the message from World Smile Day seems to be that whilst we can't control life it certainly seems a smile can significantly modify internal and external circumstances.
What's more, a smile is actually contagious - and apparently it is difficult for people not to return it because of an unconscious and automatic brain response - making both of you more attractive - and increasing your chances of a longer and healthier life.
So this would all seem to amount to some persuasive advocacy for smiles for this Friday - why not give it a go?