22/02/2016
The Importance of Smell
Aromatherapy
Our sense of smell is very important for our quality of life, our health, and our survival. We need to be able to identify toxic chemicals that threaten you, food that’s spoiled, to be able to smell smoke from a fire, and to be able to appreciate the taste of good food.
Neuroscientists Axel and Buck learned how the brain knows what the nose smells. We now know we have more genes for perceiving aroma than we have for any of the other senses – about 1000 genes, 1 for each smell, encode odor receptors lining our nose. We can perceive 10,000 to 100,000 distinct aromas.
From the odor receptors, a neuron is activated and the electrical signals are sent directly to the olfactory bulb in the front of the brain. From there, odor signals are relayed to different parts of the brain, including the limbic system, which generates our emotional feelings. Axel and Buck mapped how each individual odor and its quality activate a particular subset of receptors that activate particular parts of the brain.
Aromas can affect our emotions directly and instantaneously. We smell and react even before we can think. All the other senses are processed through the thalamus to the frontal lobes, so we think first and then react consciously. The nose and smell are wired very differently.
The amygdala in the limbic system is the brain’s emotional center. It plays a role in our sense of fear and survival behavior. Functional brain imaging demonstrates the influence aromas have on our limbic system and on our emotional pathways. The hypothalamus, pituitary, the autonomic nervous system, and vagal nuclei are affected by smell through the output of the amygdala. Our hormones and our body functions can be affected by smell.
Smell and Taste:
Smell is also important as it can affect our sense of taste. Researchers say 80% of the flavors we taste come from what we smell, which is why foods can become flavorless when you have a blocked nose. Taste buds on our tongues can only identify four qualities being sweet, sour, bitter, and salt and the remaining ‘tastes’ are actually distinguished by smell.
Smell and Memory:
Scent is the sense closest linked to memory. Studies have shown that people can remember a scent with 65% accuracy after 1 year while visual memory sinks to 50% after only a few months. The smells we experience play a crucial role in how we associate with memories and places. Whether a smell reminds you of your mother’s cooking or a childhood trip to the ocean, a distinctive scent sinks into your brain and stays there.
Smell and Emotion:
Smell has a strong influence on the emotions we feel in our daily lives. The emotions we feel effect the way we relate to places and brands. Dr. Alan Hirsch has researched ways in which smell affects human behavior. “The part of the brain that smells and tastes is part of the emotional brain where our personality lies.”
Smell and Time:
Dr. Hirsch has also led studies into the way that smells can influence our perception of time. In one of the studies, 20 separate participants were exposed to a baby powder aroma, a coffee aroma, and no aroma at all. While the coffee aroma produced a reduced perception of time, the baby powder aroma produced a longer perception of time. Likewise, pleasurable fragrances have been shown to create “dwell-time” in stores, increasing the likelihood of customers making purchases.
Smell and Health Care:
Creating a comfortable and relaxing atmosphere for patients is a challenge for every health care facility, be it large or small. Lavender fragrances have been used in nursing homes to calm residents and in emergency rooms to calm worried visitors.
Smell and Productivity:
Our sense of smell can even affect productivity in office environments. Specific smells have been found to increase alertness which in turn results in higher productivity rates. One study found that when lemon oil was diffused throughout a Japanese office building, productivity among data entry operators increased by 54%.
The Psychological Impact of Smell Loss:
Anosmia sufferers often talk of feeling isolated and cut-off from the world around them, and experiencing a ‘blunting’ of the emotions. Smell loss can affect one’s ability to form and maintain close personal relationships and can lead to depression. Going back to the points made about the strong connection between smell and memory, it can be seen that losing one’s sense of smell can result in the loss of an important sentimental pathway to memories.
