How the Nose Knows – A Scientific Guide To How We Detect Scent

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What do our noses really know when it comes to scent? We all are aware that they live on our faces midway between our eyes and our mouths, but how do noses know how to smell? What taught them and why? This conundrum can and should be better put and can be boiled down into one sentence. How does the nose smell things and what secret information does it have about its host, the smeller?

How does the nose process a smell?

The inner workings of the ordinary, run-of-the-mill nose are more complex than the interior of a modern jet liner. Processing any smell begins at the back of the nose underneath the mucus, and concerns a strip of tissue known as the olfactory epithelium. Here lie millions of sensory neurons, the tips of which contain proteins called olfactory receptor neurons. Their function is to notice the odor and bind odor molecules.

These neurons are the “locks and keys” of the olfactory system, which help identify smells. They are capable of detecting thousands of different aromas and they transmit electrical impulses to a micro-region in the brain known as the glomerulus that lies within the olfactory bulb at the back of the nose. The brain interprets these “odorant patterns” as smell. Richard Axel and Linda Buck discovered this concept in 2004 and they received a Noble Prize that same year.

Until quite recently, scientists believed that the human nose was capable of smelling 10,000 different scents. Now a new theory has emerged revealing a bigger, more fragrant truth. According to the very latest research, our noses can discern a staggering one trillion diverse aromas!

The importance of being a nose, earnest or otherwise

The nose is so much more than just a vehicle used to smell pretty flowers, and the sense of smell has played an important role in human development down through the ages. Complicated and smart, the human nose is part of our chemosensory system, which concerns the senses of taste and smell.

Sniffing out food and predators, smell evokes memories and aids in sexual attraction, love and sex. Known as the “guardian of your lungs,” the nose functions as a filter that keeps bronchial tubes moist by warming the air that you breathe.

Smell and sexual attraction

We should never underestimate the power of smell over our daily lives and choices, particularly when it comes to sexual attraction. While we might be prone to think that it arises from visual cues, research indicates that it is our unique body odors, which comprise our immune systems that subconsciously direct us to our choice of partners.

That first kiss, often urgent and unplanned, is actually primal behavior that scientists believe developed first from sniffing. While not the most romantic association, it is a truthful testament to the power of scent as one of the five ways in which we connect with the world around us.

Smell and human socialization

Although it receives no accolades, the human nose helps us navigate our social world. Perhaps this is because the actions go unnoticed and are on a deeply subconscious level. A recent study has shed new light on the concept of sex pheromones, which are chemicals emitted in body fluids such as sweat and tears.

It is believed these pheromones can impact how we view other people and can even, believe it or not, change our own hormones. New research suggests that these chemicals can reduce sexual arousal and send a signal in the animal world at least, that during emotional distress mating is not an option.

What are scent triggers?

Childhood memories associated with a particular scent remain on the verge of recall throughout a lifetime. Sometimes known as “odor-evoked autobiographical memory” or the Proust phenomenon, the term derives from a scene in the French writer’s famous novel, In Search of Lost Time. While the narrator dips a Madeleine cookie into a steaming cup of tea, the pleasant aroma transports him into a time tunnel at the end of which lies a long-forgotten bundle of memories from his childhood.

Smell has the power to mentally transport all of us to sentimental periods in time, mostly back to our early lives because memory and emotions are often associated with the olfactory bulb in the brain’s limbic system. It is this close connection that explains a scent’s scientific connection to buried memories that come flooding back upon exposure to that particular odor trigger.

Aromas such as a pumpkin pie, cinnamon, crisp apples, school glue, newspapers or fresh-cut grass evoke flashes of vivid recall. Research indicates that odors serve as indelible reminders of times past, much more so than cues received from other senses such as sight and sound. This is perhaps due to the fact that sight, sound and also touch data does not pass through the same areas of the brain; namely the amygdala and hippocampus regions that handle memory and emotion.

The amygdala and hippocampus regions of the human brain

The amygdala are located in the temporal lobe and are two regions of the human brain that profoundly affect our memories and our emotions. They are part of the limbic system and considered to be the critical matrix for emotions, emotional behavior, and motivation. The function of these almond-shaped structures is to create reciprocal connections with other regions of the brain, including the hippocampus.

The amygdala respond to diverse emotional stimuli, but mostly to those related to fear and anxiety. These two areas regulate the sense of smell and are important in the processing and memory of emotional reaction, social and sexual behavior.

The hippocampus (hiippocampi plural) which derives its name from the Greek word meaning sea horse, refers to two structures, one in each hemisphere of the brain. According to the Medline Plus Dictionary, they are “crucial to the formation, storing and processing of memory.”

The hippocampus is essential for memory function, particularly the transference from short to long-term memory, and control of spatial memory and behavior. It is one of the few sections of the brain capable of actually growing new neurons and is active in both encoding and retrieving memories.

Understanding the brain’s limbic system

The limbic system is the most ancient and primitive part of the brain because these same configurations were present in early human remains. This system is believed to be the cerebral hub of human emotions, controlling mood, memory, behavior and emotion. After the neurons in the upper part of the nose detect a smell, they produce an impulse, which is transmitted to the brain along the olfactory nerve.

The olfactory bulb is the first stop in the process of smell and it is here where the signal then passes, like a car traveling through a highway tollbooth, to other areas in the brain closely connected to it, which are collectively known as the limbic system.

How do scent triggers influence consumer behavior?

Scent triggers all concern one important and simple fact. Aromas that evoke positive memories motivate a consumer’s decision to make a purchase. Rachel Herz from Brown University, Haruko Sugiyama and colleagues from the Kao Corporation in Japan recently conducted a collaborative study to specifically identify how a product’s scent can both call to mind memories and influence the opinions of potential consumers about the appeal of a particular product.

This important study revealed some fascinating facts

This study which was completed in 2015, was entitled: Proustian Products are Preferred: The Relationship Between Odor-Evoked Memory and Product Evaluation and was published in the journal, Chemosensory Perception. Herz and colleagues sent samples of four scented body lotions to 271 American women between the ages of 22 and 31 years old.

These survey participants were asked to personally rate the different lotions for five specific qualities. These included: pleasantness, intensity, familiarity, uniqueness, and the degree to which each lotion elicited personal memories. Later, they were asked to rate how much they liked the sample lotion.

Researchers noted that study participants preferred the lotion fragrances that smelled pleasant and evoked stronger personal emotional memories. Study results clearly indicated that memories elicited from the fragrance of a product are major driving forces behind the motivation for consumer purchases.

Scent Marketing and ROI

About two years ago, The Nose Knows Design’s Scent Canister Campaign demonstrated the connection between the incorporation of a scent within a retail space and that company’s return on investment (ROI). The campaign focused on the increase of candle sales in partner stores where a specific aroma, peony blush, was added to the area of the stores where candles were sold.

Results were startling, indicating a 173.98% increase in candle sales and an overall 153.42% increase in general home fragrance product sales. The explanation concerns that all-important limbic system which processes smell.

According to highly successful designer, Raymond Matts, the man behind many famous fragrances such as Elizabeth Taylor’s White Diamonds, “At least 35% of what we recall about an environment in the short-term is scent-based, compared with about 15% of what we see. Yet marketing campaigns still tend to be sight-led… Ambience scenting is about creating an emotional appeal to your location, something that’s distinctive and will be remembered in a positive way…We’re seeing studies that show when a space is not overtly but pleasantly scented, customers tend to linger longer and are more apt to communicate with staff. People looking to sell something have their attention for a greater time-span and customers are more likely to return.”

In conclusion

Our nose knows a lot more than it tells, and more and more retailers and other industry leaders are paying more attention to the strategic influence of olfaction on the mind of the modern consumer. By understanding the process of smell and how an aroma can affect brain function, sellers of all kinds of products and services can capitalize on this fragrance bandwagon and hitch a ride leading to the land of increased ROI and customer satisfaction.

If you’re looking to marry an effective new natural, organic, or synthetic scent with your brand, we have decades of experience matching fragrance blends with products, product lines, fine fragrances and more. Speak with our team and start setting your brand apart with our vast array of proven fragrances, or create your own!

Final thoughts about noses and fragrance:

In the land of the skunks, he who has half a nose is king. – Chris Farley

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