Fragrance is like music. Personal preferences and associations greatly influence a person’s response to music’s loudness, style, and the types of harmonies being used—not to mention the lyrics—so that the response is unpredictable and its causes unclear. Much of the aromatherapy information presented as fact today is based on folklore or inconclusive early research. Dr. Susan Knasko, who has been studying the effects of odors on mood and performance at Monnell Chemical Senses Institute in Philadelphia, is acutely aware of the strength of the psychological component in human response to odor. She cites a study conducted at Monnell in which half the study group was placed in a room and told that a pleasant smell was being introduced. The other half, placed in another room, was told that there was no smell in the room. People who thought they were exposed to a pleasant smell reported greater feelings of health, positiveness, and well-being than the other group. The implication for aromatherapists is that convincing the patient of the fragrance’s properties has a far more predictable effect than does exposure to the fragrance itself.
In the face of such a strong psychological influence, focused research is difficult and the usefulness of the results dubious, especially from an economic standpoint. Studies are under way on the effects of fragrance in stress reduction: in one of these, the odor of vanilla has shown some potential for reducing stress in patients about to undergo medical procedures. However, sex and age differences, societal or cultural differences, personal attitudes, and the memories associated with specific odors play unknown roles; certain responses may occur often in the presence of particular fragrances, but none can be relied on to happen consistently.
Research is continuing in this area, but because of the subjective nature of our responses to fragrance, the results may never be as conclusive as some might wish.