When an animal faces a predator, its senses go into overdrive. So scientists wondered, could human anxiety be an evolutionary legacy to protect us against potential threats? And if so, might anxious people have a heightened sense of smell, presumably to detect predators or disease-carriers.  

Researchers repeatedly tested 14 mens’ perception of odors, including bad ones. In some trials, the men were in an MRI scanner, and odors were faint. Participants were simply asked if they could detect a scent, yes or no.

They were also tested for anxiety: their breathing and skin electrical conductivity were measured, as in a lie detector. Subjects also estimated their anxiety on a 100-point scale.

Turns out that the more anxious men were significantly better at detecting lower concentrations of scents, particularly nasty ones. They also were more likely to become emotionally aroused in the presence of bad smells. The research was published online in the journal Chemosensory Perception. [Elizabeth A. Krusemark and Wen Li, "Enhanced Olfactory Sensory Perception of Threat in Anxiety: An Event-Related fMRI Study"]

So if you wig out before, say, a driving exam, remember that anxiety may be part of constellation of physical traits that evolved for survival when the threat was an odorous lion, not a onerous licensor.

—Cynthia Graber

[The above text is a transcript of this podcast.]