Humans may be able to detect others’ happiness through more subtle indicators, such as fragrance.

A multi-university team of European researchers claims in a study published in the journal Psychological Science that when people feel the sensation of happiness, chemicals are generated in the body and expelled as perspiration. People in the area catch up on the positive fragrance and may even become happier.

After 12 healthy young men viewed movies designed to elicit a range of emotions, including fear and enjoyment, sweat samples were collected from them.

For the study, 36 healthy young women were chosen as smellers. As the women inhaled the fragrance of the sweat samples, their physical and facial responses were carefully observed. Women were the only ones included in the sample of smellers, according to researchers, because it has been established that they are more sensitive to scent and emotional cues.

After examining the women’s facial expressions, the study team concluded that the women who scented perspiration from happy males at the time displayed happy facial expressions. In other words, the aroma of the men’s happiness was detectable to the women, and this made them happy.

Previous research has revealed that unpleasant emotions like fear and anger may be expressed through perspiration. From an evolutionary standpoint, these feelings could have assisted our ancestors in recognizing when danger was present. Positive emotions would not have been as crucial for chemical communication, but they might have had other societal advantages.