Stress Makes Things Stink
When you're stressed, it can feel like everything is terrible. According to a 2013 study in the Journal of Neuroscience, that includes smells. Psychology researchers at the University of Wisconsin-Madison put 14 people into fMRI brain scans, then showed them disturbing images and asked them to smell a series of scents they had previous rated as neutral. Sure enough, being under stress made them more likely to rate those innocuous smells as distasteful.
What's even more interesting is what happened on the brain scan. Usually, the brain's olfactory, or smell center, is wholly separate from the emotional center. Indeed, when the participants smelled the neutral scents, only their olfactory centers were activated. But once they were stressed, something strange happened: instead of the olfactory and emotional centers activating separately, they essentially merged, creating a "unified network" of an emotionally charged sense of smell. This shows scientists how anxiety can produce a feedback loop, since anxiety can cause our senses to become negative, which in turn can cause more anxiety. That's an important step in our understanding of mental health issues such as anxiety and depression. Learn more about how stress affects you in the videos below.