The mysteries surrounding our olfactory systems have been the focus of Philadelphia’s Monell Chemical Senses Center since it opened, in 1968, more than 20 years before the discovery of the odorant receptors that we use to perceive scents. Today, it’s the world’s only independent nonprofit organization dedicated to interdisciplinary research around smell and taste. One of the center’s members, Dr. Pamela Dalton, a cognitive psychologist with a background in public health and chemosensory science, began creating and administering smell tests as soon as olfactory impairment emerged as a primary symptom for the novel coronavirus. We recently asked Dr. Dalton how thoughts and emotions impact the way we perceive scents, and what Covid-19 reveals about our noses.

“The loss of smell can be a devastating experience. Covid-19 is giving us an opportunity to learn not only about how viruses affect the olfactory system, but how loss of smell affects people. First, we’re trying to establish that loss of smell is possibly a more important way to screen for infection than fever checks. It turns out that, at least with the current variant of the virus established in most of the world, loss of smell is experienced by seventy to eighty percent of infected people.

Everybody is living in a [slightly] different smell world. That’s because, genetically, we have the ability to smell certain chemicals based on our individual genetic codes. Everything you do and experience—where you live, your culture, the foods you’re brought up with—appear to be the most determining factors of what you will ultimately come to accept or reject when it comes to scents.

Your emotional state affects your response to smell, too. You will be faster to react to a negative odor in a stressed state than if you are relaxed. If you smell something familiar that reminds you of a safe place or a good experience, that can actually have fantastically fast and quite large effects on your mood in real time.

If there’s one good thing to come out of this pandemic, it’s that it has brought attention to a sensory system that may be an [indicator] for a lot of other viruses, brain disorders, and diseases. This has been largely ignored until now. We don’t want to underestimate the contribution that smell can provide to people. There are all these emotional connections that we don’t take into account until they’re removed from us. Only then do we realize how much they’ve added to the multidimensional experience of our everyday lives.”