Scientists reckon they've produced the best evidence yet that a fake smile can lift your mood.
A 1988 study found that people thought cartoons were funnier when they held a pen or pencil in their teeth without letting their lips touch it, which activated the same muscles as a smile.
However, these results weren't replicated when the study was repeated in 2016.
But new research at Stanford University in California, has found a posed smile boosted happiness by about as much as looking at pictures of puppies and rainbows.
