Specific odour patterns are transmitted to various parts of the brain. Along with other sites, odour patterns are sent to the hypothalamus, the limbic system, and the cerebral cortex. These areas of the brain are responsible for managing and coordinating internal biological processes, including how we think, learn, feel and respond to our environment.



With the help of technology, such as magnetic resonance imaging (MRI), we are able to see detailed images of the brain's metabolic activity. Now scientists have been able to confirm that within our brains are olfactory-specific activities that directly relate our sense of smell to specific activities within our brains.

Other studies have shown that eight major factors of mood—such as stress, depression, apathy, happiness, sensuality, relaxation and stimulation—can be affected by fragrances. Further, because individuals react to the multiple notes within one fragrance, fragrances themselves have the ability to affect various moods. Conversely, the study notes that simple fragrances affect only a single mood state. The study explains that while complex fragrances, such as lily of the valley, have the potential to increase both relaxation and stimulation, less complex fragrances such as Douglas fir consistently induce relaxation and lower depression.

Tuberose, on the other hand, has been shown to have the ability to promote happiness and relaxation. It is suggested to invoke a sensual, romantic atmosphere while lowering depression, as does the very complex formulation within the fragrance of hyacinth.

In 1997 Dr. Robert A. Barron of Rensselelaer Polytechnic Institute conducted a study in a retail mall where he found that individuals who are exposed to a pleasant odour are more apt to help others than individuals who are not exposed to the same pleasant odour. When asked about their current mood, these same individuals claimed they felt happier than those who were not exposed to pleasant odours.

So is it really that simple—if we are upset, we just need to sniff vanilla and presto, we become instantly happy?

Yes. And no! It depends on an individual's earliest association with vanilla. The connection between scents and emotions is more complicated than one may first imagine.

Exposing ten individuals to the same sweet-smelling vanilla cookies does not necessarily guarantee that one will have ten happy individuals. This is because all of these individuals' past experiences with vanilla may not be positive. The manner in which we were exposed to aromas—our experiences and emotions associated with the aroma—in the past has a large impact on our sensation of the odour now.

Though cherry may be an appealing flavour to most of us, if we had to take cherry cough syrup as a child, we may detest the smell, taste and even hint of cherry flavouring now. For this same reason, the scent of gasoline, or even a skunk, may be repulsive to most individuals but if one associates these scents with that of a pleasant memory—say, an early summer evening or a childhood boat ride on the lake—these same scents may not be repulsive at all. The pleasantness of a scent is not universal; our reaction to many scents is highly personal depending on our own experiences with a particular scent.

Many of our olfactory likes and dislikes—both that of smell and taste—are based on our emotional reactions to these substances that may have little to do with the "taste" or "scent" of the substance itself. Indeed, smells can evoke strong and surprising reactions within all of us. Generally speaking, however, we have positive associations with odours that are familiar to us and we often dislike odours that our foreign to us.

What is interesting is that individuals often recognize a scent more quickly and show a preference for it when it is visually associated with its appropriate corresponding colour. The fragrance of a lemon is more quickly identified when it is visually paired with the colour yellow, grape with purple, cherry with red and orange with orange. Conversely, when an individual smells a strawberry-scented blue object, he or she is less likely to readily identify its scent—thus manufacturers design scented markers with their visually appropriate colours.

The magic of vanilla

One scent, however, tends to be liked by most individuals, regardless of its visual colour—be it brown, beige, white, or even pink. Vanilla. While researchers haven't agreed on any specific reason for vanilla's universal popularity, many believe that our positive childhood associations with vanilla's warm scent—homemade cookies, ice cream and milk—may be the answer. Perfume, soap, air fresheners and candle manufacturers have been quick to capitalize on this phenomenon since the 1990s.

Yet while manufactures have only recently begun to jump on the vanilla bandwagon, psychologists and researchers have been familiar with its positive emotional effects for many years, using its scent in experiments where a universally pleasant fragrance is required. Moreover, its fragrance is used on cancer patients undergoing diagnostic procedures to lessen their anxieties.

A study at Germany's Tubingen University confirms vanilla's ability to reduce the startle-reflex in humans and animals. That vanilla has a calming effect on not only humans, but on animals as well suggests that the connection between vanilla's scent and positive emotions has to do with more than just warm and fuzzy childhood memories.

Researchers have only just begun to scratch the surface about how our sense of smell relates to our various moods and many more studies, no doubt, are needed in this area.