We may never know the exact moment the first smile appeared, but we can take an educated guess—and that guess takes us back an astonishing 30 million years. That’s long before humans ever walked the Earth! It suggests that smiling isn’t just a human trait—other species must have been smiling long before us.

Researchers discovered this when they noticed something fascinating: both human and chimpanzee infants display smile-like facial movements while sleeping. These are called “spontaneous smiles”, and they’re believed to be the evolutionary roots of the smiles and laughter we share today. That might not be surprising considering how closely related chimps are to us. But what’s even more incredible? Scientists found the same spontaneous smiles in Japanese macaques—primates much further removed from humans on the evolutionary tree.

In the animal world, these early smiles likely helped to endear infants to their parents. But for us, smiles have evolved into something far more prosperous and complex. They can express joy, warmth, reassurance—even a shared secret. A smile can connect us across time, space, and species. So why not share one today?

Did you know there are many different types of smiles? Try spotting them next time you're in a busy public place!

The Science of Smiling

Charles Darwin was one of the first to study smiles, but it took another 150 years of research to understand them truly. Scientists have identified at least 19 types of smiles, yet only six are linked to happiness. Here are some of the most common ones:

Duchenne Smile – A genuine smile that lights up the eyes, discovered by 19th-century neurologist Guillaume Duchenne.

Fake Smile – Lacks eye involvement, though studies show many can now fake it convincingly.

Embarrassed Smile – Often accompanied by looking away or touching the face.

Polite Smile – Used for social niceties, with the mouth smiling but the eyes remaining neutral.

Dominance Smile – A lopsided smirk that conveys superiority, even triggering stress in others.

Flirtatious Smile – A key tool in attraction, often more influential than physical features.

A Smile Through Time

Smiling isn’t just instinctive—it has evolved. Ancient Greek sculptures showed “archaic smiles” symbolising health, while medieval Europeans saw open-mouthed smiles as improper. By the early 20th century, Hollywood and better dentistry made big, bright smiles fashionable.

The Smile Loop: Why Smiling Makes You Happier

Darwin noted that outward expressions reinforce inner emotions. Modern research proves this: Botox studies show people who can’t frown feel happier. Even pain perception is reduced when we avoid frowning. Your brain reads your facial muscles, so the more you smile, the happier you’ll feel!