There are moments when your sense of smell may catch you off guard. The light scent of your child’s hair as you hold them close. The intoxication of exotic spices in your favorite restaurant as you scan the menu. Your love’s cologne.
Scent is a powerful part of our human experience and there’s science that shows that it contributes to so much more than just our ability to know the world around us.
How Scent Works
When you first detect a smell, it is processed by the olfactory bulb, which starts inside the nose and runs along the bottom of the brain. The olfactory bulb then processes the scent and sends information to the limbic system within your brain. Scientists regard the limbic portion of the brain as playing a major role in controlling mood, memory, behavior, and emotion, making scent a key component into how we feel, remember, and behave.
Unlocking New Tastes
When most people think about scent, they also think about taste. Smell and taste work together through your body’s chemistry. Molecules released by the substances around us stimulate special nerve cells in the nose, mouth, or throat. These cells will then transmit messages to the brain, where specific smells or tastes are identified.
When you eat, your tongue is able to process only a few flavor profiles: sweet, salty, bitter, sour and umami. But there are much more complex flavors that exist - such as grapefruit, chocolate, or barbecue - that require your sense of smell to be fully experienced.
But beyond just enjoying your favorite meals, smell and taste also play important roles in warning us of dangers that can come from eating, such as the odors that come from spoiled food.
Early Warning Signs
Speaking of detecting danger, your sense of smell can also help with identifying toxic fumes or fire. In another research study, scientists found that a combination of scent and memory can be used to further “detect” danger.
In earlier periods of history, physicians also used their noses to diagnose illnesses. Patients with serious illnesses would give off distinct odors that a trained doctor could sense. While medicine has advanced well beyond a trained nose, many medical professionals still rely on their senses of smell to aid in patient care through making observation.
Neurobiologist and smell expert at the Yale School of Medicine Gordon Shepherd also notes that scent has been shown to affect what we crave, what we become addicted to, what we find pleasure in, and even the will to live. In an interview with the Boston Globe, Shepherd connects declining powers of smell in the elderly to their ability to continue to thrive, as our sense of smell and its connection to the way we experience flavor can often lead to poor nutrition.
Making Memories
The biology of scent has a close tie to memory as well.
The olfactory bulb has direct connections to two brain areas that have strong connections to both emotion and memory: the amygdala and hippocampus. When you smell something, signals are sent to these two areas of the brain which usually conjure up memories that are tied to that scent. This is why a perfume or soap may remind you of your mother or a passing sniff may take you back to the day you rode your first bicycle, graduated college, or got your first kiss.
What’s really interesting about the olfactory bulb and its process of passing information to the brain is that visual, auditory (sound), and tactile (touch) information doesn’t usually flow through the amygdala and hippocampus. This may be why olfaction (i.e. smelling), more than any other sense, is so successful at triggering emotions and memories.
Experiencing Feelings
Scents affect our emotions and perceptions, too. When you think about feelings and scent, you likely call to mind the field of aromatherapy, or the application of scent to enhance psychological and physical well-being. Aromatherapy has been used for thousands of years in the treatment of a variety of health concerns but it’s only been studied in the past 100 years or so.
In most cases, research demonstrates that aromatherapy can be used effectively to improve mood. For example, the University of Vienna found the scent of orange oil, when used in dental clinics, decreased anxiety for female patients. Psychology Today also reports that the scent of lavender can boost mood and lemon can raise one’s perception of his or her own health.
Believe it or not, your nose can also give you clues as to how others around you may be feeling and aid in empathy. According to a 2009 study, participants were able to detect anxiety in others through the body’s natural scent and also experienced similar feelings of anxiety. Additionally, another’s body odor can contribute to our attraction through the subtle detection of genetic compatibility.
It’s More than You Think!
From keeping us safe to helping us experience our favorite foods to affecting our moods and memories, olfaction is so much more than just our ability to smell.