“Being exposed to sweat produced under happiness induces a simulacrum of happiness in receivers, and induces a contagion of the emotional state,” said study author Gün Semin, a professor at Utrecht University, in a statement. “Somebody who is happy will infuse others in their vicinity with happiness.”

Determining how sweat affects the happiness of the people who smell it required some unusual experiments. Researchers showed film clips to a group of 12 men that inspired either fear or happiness. A control group of men was shown neutral scenes. After screening the clips, researchers collected sweat samples from the men by placing pads in their armpits and asked 36 women to smell a vial with the scent of the pads. Researchers measured the facial expression prompted by each sweat sample. Women smiled more when they smelled the sweat of happy men than sweat made after men watched a neutral video clip.

The study is small and more research is needed. Previous research has shown that chemosignaling—or conveying emotion through smell—can inspire negative emotions in others, but these findings show that smells might be able to inspire happy emotions, too.