How Do Scent and Aroma Impact Behavior?
Jimmy Durante, image from flikr
How are emotion and behavior impacted by scent?
How does context impact reaction to scent?
Some psychologists (Rachel Herz, Trygg Engen) have proposed that response to specific odors is learned rather than innate. For example, Herz cites a woman who had and extremely adverse reaction to the smell of roses because she first smelled them at her mother’s funeral.
There are also cultural variances to the response to certain scents. In the United States the majority of people react positively to the aroma of wintergreen. Conversely, older British citizens find it unpleasant due to its association with a specific analgesic rub popular during World War II.
Other than biological reasons (nasal irritants) that some people don’t like certain scents, Herz and Engen believe that response to different scents is a learned behavior.
Despite our belief that sight and hearing are the two most important senses to our survival, from an evolutionary perspective smell is one of the most important senses. To recognize food or to detect poison, smell is the sense that almost all other mammals use. Because of this basic feature yet vital role, smell is one of the oldest parts of our brain.
Engen maintains that smell serves as a kind of “index keys” to quickly retrieve certain memories in our brain. This primitive yet essential role is probably why smells trigger memory more than does seeing or hearing.
It is said that people can identify about 10,000 different smells (Harvard, 1999). These rang from flowers to fried chicken. But when scientists look closely at the nose, that proclamation doesn’t make sense.
Harvard Medical School discovered that mice have approximately 1,000 different sensors in their noses. Humans are thought to have about the same number. This begs the question, how can a human identify 10,000 different smells with 1,000 sensors?
Inside the top of your nose is a small patch of tissue crowded with millions of nerve cells. Each nerve cell contains one type of the 1,000 different sensors. Each receptor recognizes multiple odorants, and a single odorant can be recognized by multiple receptors. These are the molecules that humans and other animals perceive as smells. So the different combinations of receptors can identify 10,000 odors. The same way the letters in the alphabet can be rearranged to form different words.
Odor on the Brain
A small shift in the concentration or make up of the molecules can change the perception of an odor from pleasant to disgusting. These changes can quickly move a reaction from fear and loathing to the realms of sex and pleasure.
Memory of Smell
Memories associated with a specific fragrance can trigger changes of behavior. The smell of rotten food sparks a revulsion response. The aroma of a roasting turkey brings back childhood recollections of holidays and family.
The Smell of Taste
Humans may have an ability to sense chemical signals from each other without being aware of it. Other animals have this second system which enables them to detect sexual and social information via substances known as pheromones. A whiff of a pheromone from a male rat in its territory may spur another male to a quick attack. Such signals exchanged between males and females incite mating.
Animals detect pheromones via a special organ located in the septum that divides the nose. However, pigs recognize at least one pheromone by using the same sensors in the top of the nose that humans use to smell food. This leads researchers to speculate that humans may have the ability to detect pheromones and these chemicals, in turn, influence their behavior.
No one has ever isolated and identified a human pheromone. So, don’t rush out and buy a case of the latest male cologne based on the commercial which implies it will attract a pride of young, fertile females; at least not human females.
Elemental Value Added Truth: “Something is rotten in the state of Denmark” Marcellus (Character). Hamlet, Act I, Scene 4, William Shakespeare.