They say dogs can smell fear The findings, published in the journal Psychological Science, suggest that humans communicate via smell just like animals. Researchers had male participants watch movies that either induced feelings of fear, or feelings of disgust. For the two days before, they were told to be very careful about smell contamination - meaning they couldn't eat smelly foods, drink alcohol, smoke, exercise a lot or use their own hygiene or detergents. After the male study participants watched the movies, the researchers gathered samples of sweat from them. Then, female study participants were exposed to their sweat as they carried out a task, with their facial expressions and eye movements monitored. Researchers found that the women's facial expressions and eye movements were indicative of the kind of sweat they smelled - when they smelled the sweat taken from men watching the scary movie, they looked fearful. Think dogs know when you're scared? Perhaps we all do, and it's all in our sweat.