A groundbreaking study from Rutgers University-New Brunswick debunks a 19th century myth that humans’ sense of smell is inferior to dogs and other rodents. Neuroscientist John McGann, associate professor in the Department of Psychology, School of Arts and Sciences, says that humans can discriminate maybe one trillion different odors. Researchers previously believed that humans were only capable of distinguishing about 10,000 different odors. For 150 years this misconception was held dear and perpetuated by entry-level psychology textbooks.
Even though humans’ olfactory bulb is small for their size, it still contains a similar number of neuron pathways as other animals. The sense of smell is often associated with animalistic behavior, and apparently humans have tried to separate themselves from their most primordial senses. “It has been a long cultural belief that in order to be a reasonable or rational person you could not be dominated by a sense of smell,” says McGann. “Smell was linked to earthly animalistic tendencies.”
The sense of smell helps our brain perceive our environment, subliminally strengthening instinct and intuition. The odors we smell affect our emotions, memory, and nervous system. Like any other sense, the olfactory system can suffer damage and desensitization. The problem today is the onslaught of artificial fragrances. These chemicals, found in dryer sheets, laundry detergents, “air fresheners,” shampoos, soaps, body mists, room sprays, colognes, deodorants, and perfumes actually weaken our ability to sense our natural environment. These chemicals are addictive, disconnect us from nature, and cause immune system hypersensitivity. McGann says that some research suggests the loss of smell is linked to memory loss in diseases like Alzheimer’s and Parkinson’s. If true, the numbing effect of artificial fragrances are quietly contributing to this epidemic.
There are striking differences between natural scents and artificial fragrances. The natural scents that come from our environment sharpen our olfactory system. The essential oils that come from flowers, leaves, and trees provide aromatherapy benefits. Artificial fragrances, on the other hand, are made from petroleum and coal tar. These chemicals cause addiction as well as disruption of the human endocrine and immune systems, among other issues. These synthetic scents dull the olfactory system, suppressing our ability to smell and enjoy a wide spectrum of real scents. As confirmed by Health Impact News, artificial fragrances are carcinogenic. Over time, sensitivity to these chemicals may manifest. This sensitivity is good; the body is warning the conscious self to avoid these toxins. The sinus cavities can become inflamed and full of pressure, restricting breathing. Skin reactions may occur, especially to laundry detergents and dryer sheets.
As our ability to sense our natural environment dissipates, our mood and mental health is affected, too. Sigmund Freud wrote how a diminished olfactory system made humans susceptible to mental illness. This may be why people who smell natural essential oils see improved mental health and cognitive benefits. Stimulating the olfactory system with natural scents helps restore the nervous system.
The olfactory receptor neurons in the nose are constantly at work. Even when we aren’t conscious of this sense, it is working, making physical contact with the molecules in the air. This information is then sent to the back region of the brain for processing.
Writing in the journal Science, McGann says, “We can detect and discriminate an extraordinary range of odors; we are more sensitive than rodents and dogs for some odors; we are capable of tracking odor trails; and our behavioral and affective states are influenced by our sense of smell.”
The difference between humans and animals is that humans survive using their free will and complex decision-making processes; whereas animals rely heavily on simple sensory input. Humans take their sense of smell for granted but it still influences their understanding and behavior. The bombardment of carcinogenic artificial fragrances is altering human activity and numbing our connection with nature.