The stuff that of pulp fiction; may just about have an explanation in science.
According to researchers who have investigated the underarm secretions of petrified skydivers, people can unconsciously detect whether someone is stressed or scared by smelling a chemical pheromone released in their sweat.
The team found that the smell of fear triggered a heightened response in brain regions associated with fear when inhaled by volunteers in a brain scanner. The research suggests that, like many animal species, humans can detect and subconsciously respond to pheromones released by other people.
"The smell of fear" turns out to have a foundation in science.
Just like a sixth sense, the chemical transfer of anxiety can also cause a feeling of discomfort in the perceiver.
Exposure to the smell of fear biased women toward interpreting facial expressions as more fearful, but only when the expressions were ambiguous. It had no effect when the facial emotions were more discernable.
Most researchers do not believe that humans can detect pheromones. This is done in other animals using a structure in the nose called the vomeronasal organ (VNO), or the Jacobson's organ. Although humans have this auxiliary olfactory sense organ, it is not connected to the brain. However, human pheromones could still be detected and some small studies have suggested that human behaviour can be modified by an alarm pheromone.