PSYCHOLOGY AND SMELL
How Smell Works
There are two ways we detect smells:
1.In the air we breathe, through the front of the nose (orthonasal olfaction)
2.Through the back of our notes from our mouth, when chewing food (retronasal olfaction. This is how we appreciate the flavour of food when it is our mouth and why any people suffering from a smell disorder believe there is something wrong with their sense of taste.
Upon detecting a smell the olfactory neurones in the upper part of the nose generates an impulse which is passed to the brain along olfactory nerve. The part of the brain this arrives first is called the olfactory bulb, which processes the signal and then passes information about the smell to other areas closely connected to it, collectively known as the limbic system.
The limbic system comprises of a set of structures within the brain that are regarded by scientists as playing a major role in controlling mood, memory, behaviour and emotion. It is often regarded as being the old primitive part of the brain, because these same structures were present within the brains of the very first mammals. Knowing this helps us to understand why smell plays such an important role in memory, mood and emotion.
Smell and Memory
The sense of smell is closely linked with memory, probably more so than any of our other senses. Those with full olfactory function may be able to think of smells that evoke particular memories, the scent of an orchard in blossom conjuring up recollections of a childhood picnic for example.
This can often happen spontaneously, with a smell acting as a trigger in recalling a long forgotten event or experience. Marcel Proust in his "Remembrance of all Things Past" wrote that a bite of a madeleine vividly recalled childhood memories of his aunt giving him the very same cake before going to mass on a Sunday.
Smell and Emotion
In addition to being the sense most closely linked to memory, smell is also highly emotive.
The perfume industry is built around this connection, with perfumers developing fragrances that seek to convey a vast array of emotions and feelings from desire to power, vitality to relaxation.
On a personal level, smell is extremely important when it comes to attraction between two people. Research has shown that our body odour, produced by the genes which make up our immune system, can help us subconsciously choose our partners. Kissing is thought by some scientists to have developed from sniffing, that first kiss being essentially a primal behaviour during which we smell and taste our partners to divide if they are a match.
It is likely that much of our emotional response to smell is governed by association, something which is borne out of the fact that different people can have completely different perceptions of the same smell. Take perfume for example, one person may find a particular brand "powerful" "aromatic" and "heady" with another describing it as "overpowering", "sickly" and "nauseating". Despite this however, there are certain smells that all humans find repugnant, largely because they warn us of danger, the smell of smoke, for example or rotten food.