It's taken for granted that animals can smell extreme emotions like fear, but can humans? In fact, a study published in the journal Psychological Science has found that, yes, humans can - and the emotions are contagious.
Most animals are able to communicate emotions through smells. But, because humans no longer have the odor-sensing organs that other animals have, it was believed that humans no longer had that capacity. Researchers had theorized that the ability had slipped away with the development of language.
Gün Semin and his colleagues from Utrecht University in the Netherlands conducted a study that tested this hypothesis. The study used 46 participants in all. Ten men watched frightening clips of the classic horror move The Shining or saw repulsive scenes from the music television channel MTV's program Jackass. While the participants watched the clips, researchers collected sweat from their armpits.
The research team chose women to be the recipients of the smells because previous studies have found women to be more attuned with men's scents than the other way around. The next step of the study involved 36 women taking a visual test. While they were distracted by this test, researchers introduced them to the smell of the men's sweat scents. When the women inhaled the men's sweat that had been produced out of fear, their faces mimicked the feeling of fear unconsciously, opening their eyes wide in a scared expression. When the women inhaled men's sweat that had been produced out of disgust, their faces grimaced, like they too were repulsed.
Because of the study, researchers believe that humans can communicate at least some emotions through scent - a useful trait particularly in crowded settings.
"These findings are contrary to the commonly accepted assumption that human communication runs exclusively via language or visual channels," the researchers wrote.