The science behind the scent

The nose knows

The sense of smell (or olfaction) is our most primitive sense and is located in the same part of our brain that effects emotions, memory, and creativity. The sense of smell works 24 hours a day and is the one human sense that cannot be ‘switched off’. It is the body’s initial and most definitive tester, instantly evaluating whether an environment is good or bad.

The human sense of smell affects 75% of daily emotions and plays an important role in memory. Humans are able to distinguish over 10,000 different odor molecules. When inhaled, these odor molecules travel into the nose and interact with odor receptors. The odor receptors then transmit the information to the olfactory bulb, which is located in the brain’s limbic system. The limbic system also controls memory and emotions, and is connected to the pituitary gland and hypothalamus area that controls the release of hormones that affect our appetite, nervous system, body temperature, stress levels, and concentration. Since the olfactory system is located in the brain, the sense of smell is closely tied to memory, mood, stress, and concentration.

Emotion can be communicated by smell. There are suggestions that smell can influence mood, memory, emotions, mate choice, immune system and hormones. Academics and researchers agree that scents are effective simply because they create a mood which validates intentions.

The senses of smell and taste, two of the five senses identified by Aristotle, are called “chemical senses” and are sometimes regarded as one sense rather than separate senses. About 80% of what we taste is actually due to our sense of smell. Without the sense of smell, we would only be able to recognize five tastes: sweet, salty, sour, bitter, and savory. A food’s flavor can be altered by simply changing its smell, while keeping its taste the same. In fact, our sense of smell becomes stronger when we are hungry.

An odor is a chemical dissolved in air, generally at a very low concentration, which we perceive by the sense of smell or olfaction.

Trials prove

The perception of all odors is subjective and based on cultural conditioning or emotional state. The human olfactory system adjusts over time and has trouble detecting both bad and good odors provided they are not too strong. This is called olfactory adaptation and it usually takes an hour to become adapted to an odor or scent. For example, people working in a scented environment often adapt to the scent and lose their ability to detect it even if people entering the space can readily perceive it. Studies show that a pleasurable scent diffused at a noticeable level can validate consumer intentions, improve workplace productivity and assist with health and medical conditions: A trial undertaken in a USA casino showed that gambling revenue increased by 48% with the introduction of a pleasant aroma into a test area. The trial concluded that a noticeable scent in the air acts to enhance the mood and intention of patrons, without affecting judgement or exacerbating obsessive gambling behaviour.1 In a 1989 trial, customers spent more time browsing at a jewellery counter when a scent was introduced.2 When the aroma of baked bread was released in a US supermarket, sales in the bakery section increased threefold.3 The diffusion of lavender during breaks at work has been found to prevent the deterioration of work performance.4 An Australian university is using scents to assist in the diagnosis of several brain disorders including Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, schizophrenia and obsessive-compulsive disorder.5 Research in Japan is being undertaken to understand the influence scent and the use of essential oils has on the treatment of Alzheimer’s disease.6 Research has also found that continual exposure to a particular scent can assist in weight loss.7 At Memorial Sloan-Kettering Cancer Center in New York, doctors use fragrance to reduce anxiety during medical testing.

Doctors from Duke University Medical Center are treating women in menopause with fragrances to alleviate depression and mood swings. This use of scent to affect mood or behavior is called aromatherapy. Anosmia is the loss of one’s sense of smell. The inability to smell can lead to loss of appetite, libido, and depression linked to smell memories. Anosmia is sometimes an early symptom of Alzheimer’s and Parkinson’s Disease as Alzheimer’s and Parkinson’s are degenerations of systems associated with the Limbic System.

1. Hirsch, 1995, Psychology and Marketing
2. Knasko, 1989, cited in The Journal of Marketing, USA
3. Hirsch, 1995, International Journal of Aromatherapy
4. Sakamoto, et al, 2006, cited at http://chemse.oxfordjournals.org
5. University of Melbourne, 2006, cited at http://www.unimelb.edu.au/
6. Miyazawa, 2006, Inhibition of Acetylcholinesterase Activity by Tea Tree Oil & Constituent Terpenoids
7. Sweet, 1997, Scents and Nonsense: Does Aromatherapy Stink

The natural power of essential oils

There is also strong acceptance that essential oils provide medical and health related benefits. 100% pure essential oils are derived from the essence of plants. Therefore they carry the health and cleansing properties of those plants.

Essential oils eliminate bad odours rather than simply mask them, including cigarette smoke. Essential oils, when inhaled as diffused oil micro-mist, help to boost the body’s immune system. Scientific research confirms that essential oils fight and eliminate airborne microbes of bacteria, viruses, and moulds.

Many hospitals in the United Kingdom diffuse pine oil in burns units to prevent the spread of infection.

Research undertaken in 1955 found that 21 essential oils reduced or totally destroyed a number of microbes that cause health complaints within 3 hours. Essential oils have been part of cough medicines for many years. A number of essential oils are used within common cleaning and anti-bacterial products.