Scent and Attraction: How Certain Smells Create Chemical Reactions In The Mind.

We all know about the five different senses — sight, smell, sound, taste and touch — but how much does each of us know about how they specifically work? We all take for granted the fact that our taste buds react to different flavors, how our sight photoreceptors take in different wavelengths of light, and how a hand close to touching a hot stove will automatically alert the brain that danger is imminent. Our sense of smell or, olfactory sensation, is also very good at detecting different scents and causing various chemical releases in the brain according to those different odors. This is especially interesting when it comes to attraction — how certain smells can influence the chemistry of the brain as well as our feelings for someone or something.

You know how two dogs will say hello by a thorough sniff of each other’s butts? Well, humans do not do that per se, but we do exchange scents far more than we are aware of. Rubbing noses with someone that you care about (think: Eskimo kisses) is not only a super cute thing to do, but was actually designed as a means to sniff out that other individual. There are many ideas regarding scent and attraction and how what we smell influences our brains.

What we smell influences our brain.

Some scientists have attributed many of our feelings of attraction to the idea of pheromones. While studied and proven extensively in animals, direct evidence of their existence in humans has yet to be produced. That does not stop these scientists from arguing that our perceived post-gym B.O. is actually a way for the body to communicate and flirt with someone. The olfactory system is constantly working to distinguish between thousands of chemical compounds and their associated smells — like dogs, we too may be involved in unconscious chemical communication.

Charles Darwin, upon noticing that horses moved their nostrils when excited by love, was one of the first people interested in how smell influenced bodily functions. Human odours in the form of sweat and other secretions have been shown to influence the reproductive readiness of other humans. This can be seen in fluctuations in the timing of a woman’s menstrual cycle when she is exposed to the sweat, or what could be the pheromones, of other women. In terms of attraction, babies have been studied and reportedly are drawn to the smell of their mother’s odor print - her personal scent that is dependent on health, genetics, environment and diet, and is different for each person.

Our personal scents may also be influenced by the ‘Compatibility Gene.’ Similar to the idea of pheromones, this gene is reportedly the aromatic effluence produced by our immune system. Scientists believe that a short arm of chromosome six and its residing genes influence how attractive each of us are to a potential mate. The thought is that these genes will produce a scent that is perceived to be attractive for a mate with optimally matched genetics.

The ‘smelly T-shirt experiment’ is a notoriously referenced study when it comes to smell and attraction. When females were assigned with ranking the t-shirts containing the natural odor of a male, their ratings of intensity, sexiness and pleasantness indicated that our partners’ smell may contribute to our survival as a species. Women tend to prefer the smell of a mate with different compatibility genes, meaning that their offspring would have a genetic advantage.

The immune system of the human body does much more than just support us during periods of illness. The immune cells provide signature cells that give each tissue of the body identity. We all produce HLA (human leukocyte antigens) molecules — these exist in pairs, one molecule from each parent. These molecules help determine what cells are ours, detecting for potentially dangerous foreign ones. By smelling out a potential partner, finding one with a HLA molecules that are similar, but not exactly the same as ours will, in theory, produce healthier offspring.

The olfactory receptors are activated by many different molecules and, depending on which receptor the odor molecules bind to and activate, can produce a multitude of responses. The brain processes odorous information using past experiences of smell, memory and learning — along with many other methods that we have yet to fully understand. With the ability of our brains to identify trillions of different smells, it is no wonder that our noses lead us to both foods — and potential partners — that we are attracted to.

Joe Masters
Joe Masters is a scientist in the fields of biomedical engineering, epigenetics, RNA mediation and rhinology. In 1987, he completed his masters in biotechnology from Griffith University and has authored several highly regarded publications in neuropharmacology, neuroscience, and biological functioning of lesser known human anatomy including the vomeronasal organ. He currently maintains a profile at FrontiersIn (http://loop.frontiersin.org/people/419291/overview) where he answers scientific questions from researchers, and also runs a hobby blog at houseofpheromones.com