Humans rely more on their eyes and ears while dogs and mice depend on their smelling ability to detect food, recognise trails and territory, identify kin and to find a receptive mate. A canine-bred blood can pick up a 24 hour old trial to identify the criminal. This remarkable characteristic makes dogs an integral part of our security system. It is also reported that horses and dogs can recognise fear in men by odour alone.
A house with infants may smell in a particular manner with the combination of milk, oil, excretion and clothes. A sugar factory smells differently and chemical laboratory generating hydrogen sulphide smells differently. Several theories of smelling and deciphering odour have been proposed by scientists. Smell is a chemical analysis procedure. Understanding smelling, its effect on other sensory organs and the conclusive mechanism of smelling are still beyond human exploration.
SMELL ACTS AS EARLY WARNING SYSTEM
Identifying smells is our brain’s way of telling us about the environment. It is our brain that interprets the smell of burning milk and we rush to our kitchen. Our sense of smell also warns us about not consuming something that is rotten. Smelling is a prior indication of the event and acts as early warning system.
The sense of smell also helps to savour our food. When we think about taste, most of us just think of tongue. But in reality we could not taste anything without the help of our nose. The ability to smell and taste go together because odours from food allow us to taste more fully. Take a bite of food and think about how it tastes. Then, pinch your nose and take another bite to notice the difference. In fact, ninety percent of what is perceived as taste is actually smell.
Most of the flavour of food comes from its aroma, which drifts through our nostrils to the cells in our nose and also reaches these cells through a passage way in the back of the mouth. Our taste buds provide only four distinct sensations: sweet, salty, sour and bitter and other flavours come from smell. When the nose is blocked by a cold most of the food seems bland or tasteless.
SMELL GIVES US UNIQUE IDENTITY
Smell gives us all unique identity. All of us have unique smell just as our fingerprints. The apocrine glands, situated in our armpits, sternum, groin, nipples, cheeks, eyelids, ears and scalp secrete compounds that are virtually odourless. They become smelly by the action of bacteria – particularly those living under the armpits. The combined effect of these determines the odour of human beings. All of us has a unique smell, which is different from others. Most interesting, identical twins have same smell and even dogs cannot distinguish between them.
SMELLING IS AN ART
Smelling is a chemical analysis procedure. Sniffing is a chemical sensory activity and is accomplished with the help of nose. The olfactory epithelium situated above the nasal cavity plays a role in smelling. The olfactory epithelium contains special receptors that are sensitive to odour molecules that travel through the air. There are hundreds of different odour receptors which are very small and each with the ability to sense certain odour molecules.
Smelling is an art because quantification of smell is difficult and attaching a different tag to an odour is next to impossible. We can detect around 10,000 odours, but how can we tell one from the other is still unknown.
SMELL EFFECTS OUR MOOD AND PERFORMANCE
Scientists think we have many different receptors that “light up” in various combinations in response to different scents. But it is difficult to explain the different qualities of smell, frequency coding and stimulus intensity
Good odour of food makes one feel more hungry, and good fragrance soothes our nerves. From our common daily life experience we can know how the odour effects our mood. We definitely do not feel good at a place which is stinky and we are more likely to be in a bad mood. Similarly opposite of that, a good smell enhances our mood when we enter a room with pleasant smell.
That is why major brands have invested a lot in scent market and its a billion dollar business.
SMELL IS DIRECTLY LINKED WITH EMOTIONS
Smell can evoke strong emotions specially in attraction and building connection with the partner. The fragrance of surroundings and your partner plays a strong role in connecting and association. This may be the reason, that the room of newly wedded couple is decorated with scented candles and flowers.
Pleasant fragrances also effect our perceptions and evaluations about other people. A person seems to be quite attractive if he/she smells good despite of simple dress up. On the contrary, if person does not smells good, people resist to talk irrespective of the thing, how well dressed he is.
Sense of smell is closely linked with memory. Scent gets tied in our memory and we remind the situation back when we are exposed to same smell.
SMELL AND RELAXATION
Stress is what we all face in life, whether it is young or aged. Studies have shown that pleasant smell is effective to reduce stress level in people as it soothes and calms our mind of all age groups. Fragrance manufacturers have for many years been trying to demonstrate that certain smells are relaxing. There are companies that market perfumes with claim that they do relax you. This can in theory be done using EEG (Electroencephalography). One of the brain waves measured by EEG is called “alpha wave” which have a particular frequency of 8 to 12 Hz.
Increased alpha wave activity in our brain is a sign of relaxation or more correctly speaking a lower state of arousal, since they are produced in drowsy state or just before falling asleep.
As we age, our sense of smell declines. This also effects our sense of taste with the result that food also loses its flavour. By 80 years of age, 80 percent of people have some major smell dysfunction and 50 percent are anosmic by the standards of young people. Not only we lose our sense of smell, but also loose our ability to discriminate between smells.