Human Smell of Fear is Contagious

New research proves humans, when frightened, emit a particular odor that turns fear contagious. In fact, just a whiff of the odor of fear can turn an ambiguous situation into a frightening one.

"Our findings provide direct behavioral evidence that human sweat contains emotional meanings," says Denise Chen, a psychologist at Rice University in Houston.

In a recent study, male participants watched neutral clips, slapstick comedies and horror flicks, while a gauze pad in their armpits collected sweat. Later, female participants smelled the gauze pads as they watched images of faces that changed from somewhat happy to neutral to somewhat fearful.

• Researchers chose males as sweat donors because of their larger apocrine sweat glands. The men used only scent-free shampoo, conditioner and soap provided by the lab several days beforehand, and kept a diet journal to avoid odorous foods such as garlic, onion and asparagus.

• The study also used female respondents because of their better sense of smell and higher sensitivity to emotional cues.

The women were more likely to interpret ambiguous faces as fearful when they were smelling the "fear sweat," but only in the case of ambiguous faces. They still interpreted somewhat happy or somewhat scared faces according to what they saw.

Click here to read the complete LiveScience article.