Many poets and philosophers have been speculating on the emotional reactions provoked by odors but it is not long since real scientific studies on the matter are available.
The group of Warwick has demonstrated with an important experiment (Kirk smith, Van Toller and Dodd, 1983) the possibility to establish a long-lasting association between an odor and a state of mind which could therefore be provoked later on by the mere perception of the same odor.
In these experiments, the state of mind experienced was negative. It was produced as a reaction to a stressing situation, but in the same period, the studies of King suggested the possibility to induce positive emotions and states of relaxation using the same method.
In both the cases, the conditioning happened at the unconscious level, in fact the subject studied in the experiment ignored that they were being exposed to a fragrance.
The odor was used in a subliminal manner which means that it was so week that they were not consciously aware of it.
It is so obvious that every one of us has been unconsciously conditioned in the same manner since childhood by the smells that form our “olfactory culture”, and it is not difficult, with the olfactory scenographies of events, to direct the state of mind of a public by a skilled use of these very smells.
It is easy to understand for instance that the smells which belong to our childhood experiences of summer holidays will have a positive antistress effect and that familiar odors belonging to home and family will be reassuring and able to give a familiar value to anything.
It is possible to anticipate the psychological effect of a great number of the scents on a particular public, knowing the substance of their common olfactory culture.
Our olfactory memory has the particularity that the older is the olfactory record, that is, the nearest to infancy, the most powerful is the emotion it will provoke and the easier it will be activated.
Olfactory memories are indelible, they will never vanish. Their force depends on the strength of the emotion that was experienced together with the smell but it also depends on the importance that the situation in which the odor was perceived has had in the learning process of a person.
More ancient they are the olfactory memories, the deeper are the emotions that they awaken and the first infancy olfactory memories are indeed the ones more likely to generate positive and pleasurable emotions.