A new study published in the Psychonomic Bulletin and Review Journal says that laughing can make you look two years older than when you have a 'poker face'.
A group of 40 participants were quickly shown a number of photographs of people who either laughed, looked surprised or had a neutral facial expression.
The results showed that people with a surprised expression looked the youngest, and those with a smile looked the oldest - even though they were photos of the same people.
"Surprisingly, when we asked the participants later about their perception, most remembered that they had identified the smiling faces as the youngest," said lead study author Melvin Godal.
"They didn't even know that they had 'aged' smiling faces. Their perception and their beliefs were in stark contrast."
Godale says it is also at odds with skin care ads, including anti-aging and teeth-whitening products, the Independent reports.
His assumption is that we 'age' people who laugh because we cannot ignore 'laughter' lines, which form around the eyes when people laugh. On the other hand, the expression of surprise on the face smooths out those same wrinkles.
Bonus video:
