Ever noticed how there are basically two types of smiles: a genuine smile and a fake one?

This distinction has been of interest to researchers for quite some time now. In fact, the genuine smile has a name. It's called the "Duchenne smile," named after the French physician Guillaume Duchenne, who studied the physiology of facial expressions in the nineteenth century.

The Duchenne smile involves both voluntary and involuntary contraction from two muscles: the zygomatic major (raising the corners of the mouth) and the orbicularis oculi (raising the cheeks and producing crow's feet around the eyes).

A fake smile or, as I like to call it, a "say cheese" smile, involves the contraction of just the zygomatic major since we cannot voluntarily contract the orbicularis oculi muscle.

This is interesting, but why is it so? What's going on upstairs that creates these two different smiles?

Scientists have discovered that these two types of smiles are actually controlled by two completely different parts of our brain.

When a patient with damage to the motor cortex on the brain's left hemisphere attempts to smile, the smile is asymmetrical, with the right side of the smile not moving as it should. However, when that same patient spontaneously laughs, the smile is normal with no asymmetry. This means that the genuine smile is controlled by some other part of the brain.

Now, when a patient with damage to the anterior cingulate (part of the limbic system) in the left hemisphere attempts to smile, there is no asymmetry. The smile is normal. However, when that same patient tries to smile spontaneously, the asymmetry appears.

Limbic System

Thus, the "say cheese" smile is controlled by the motor cortex while emotion-related movements, like the Duchenne smile, is controlled by the limbic system (the emotional center of the brain).

But, does it truly matter if your smile is contrived or authentic?

Apparently, it matters a great deal to your life satisfaction and quality of .

Researchers Dacher Keltner and LeeAnne Harker from the University of California, Berkeley analyzed the smiles in 141 photos from the 1960 Mills College yearbook. They divided the photos by Duchenne smiles, Say Cheese smiles, and the non-smilers.

The researchers followed up with these women at age 27, 43, and 52 and asked them questions about their life satisfaction and status of their marriage. They found that the Duchenne smile predicted positive outcomes in marriage and well-being up to 30 years later.

So remember, a genuine smile will probably make you happier than you think.

And as for me ...

Well, in the words of the brilliant Will Ferrell, who played Buddy in the holiday movie Elf:

"I just like to smile! Smiling's my favorite."

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