What would happen if you didn't smile?

Choosing not to smile could prevent wrinkles. No joke. 

Smiling causes skin to overlap around the eyes (think: crow's feet). Over time, wrinkles form. 

"If someone chose not to smile, they may have skin that looks more youthful, despite possibly looking joyless," Dr. Robert Anolik, fellow of the American Academy of Dermatology said in an email. "In the near term, there would be no deep lines forming at the crow's feet area. In the long run, someone wouldn't develop as many permanent creases or deeper creases at the crow's feet."

Lack of expression won't prevent all wrinkles though, said Dr. Tina Alster, director of the Washington Institute of Dermatologic Laser Surgery. Most wrinkles (those on cheeks, around the mouth or under eyes) aren't caused by muscle contraction, but actually ultraviolet light exposure, Alster said. 

In fact, she said frowning actually causes more wrinkles (in the brow) than smiling. 

"It takes more muscles to frown than to smile (that's why it should be easier for people to 'put on a happy face')," Alster said via email. 

Avoiding to smile could also affect psychological wellness. 

"Smiling is one of the fastest and easiest ways to create social connection between people," American happiness researcher Shawn Achor said. "Research shows social connection is the greatest predictor of long-term levels of happiness." 

Research has shown smiling decreases stress and could even increase lifespan. 

Related: 

Why you shouldn't tell a woman to smile

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