The Olfactory memory Refers to the memory of odors. Smells can bring us a lot of memories. This is because the Olfactory bulb , Which is a region of the central nervous system that processes sensory information from the nose, is part of the limbic system .
Since the limbic system is an area closely associated with memory and emotions, smells can evoke memories and trigger strong responses almost immediately.
How does the association between smells and memories form?
He Olfactory bulb Has access to the amygdala, which processes emotions, and hippocampus , The structure responsible for associative learning. Despite the connections between the structures, the scents would not evoke memories if it were not for the conditioned responses that have formed over time.
When you first smell something, you unconsciously link it to an event, a person, an object, a moment or a place. your brain Forges a link between the smell and a memory, associating, for example, the smell of chlorine with summer or the smell of lilies with funerals.
When you find yourself again with the smell, the link is already formed and ready to elicit a memory or even a State of mind . The chlorine smell can make you feel happy because it reminds you of summer time at the pool with your friends.
Lilies, however, could become inexplicably melancholic. This is, in part, the reason why not everyone prefers the same odors: by pure association.
Since we find most of the new smells during our childhood and youth, smells often evoke memories of childhood. However, we actually begin to make associations between smells, emotions and memories before even being born.
Children who have been exposed to alcohol, tobacco smoke or garlic in the womb of their mothers often show a preference for these odors. To them, smells that can annoy other babies seem normal or even pleasing to them.
The role of the amygdala
The amygdala Is an almond-shaped brain structure that processes everything relative to our emotional reactions. It is one of the most primitive areas of the human brain.
It is also associated with memories and the memory In general, since many of our memories are related to some emotional experience.
A decade ago, olfactory psychology expert Rachel Herz and her colleagues at Brown University tested whether there was a correlation between the emotional intensity of an odor-triggered memory and the activation of the amygdala.
The participants described, first of all, a positive memory triggered by a particular perfume. Afterwards, they went to the laboratory to participate in a Functional magnetic resonance imaging .
Participants were exposed to various sequences of visual and olfactory stimuli. The visual stimuli included an image of the perfume that the participant had chosen and an image of an unbranded perfume. The olfactory stimulus included the perfume chosen by the participant and the unbranded perfume.
If the stimulus caused some memory or emotion, the participants were instructed to keep it in their mind until the next stimulus occurred.
When participants smelled the perfume they had chosen, it was when they showed increased activation in the amygdala and the parahippocampal gyrus (a region surrounding the hippocampus).
These data suggest that smells that trigger emotional and strong memories also trigger high activity in areas of the brain strongly related to emotions and memory.
However, it is important to know that in this study only five people participated, and all were women. To confirm these findings, studies with a larger sample of participants are needed, where there are both men and women.
Several behavioral studies have shown that odors trigger more vivid emotional memories and are better at inducing that feeling of being transposed into the past than images.
However, there have been few studies, since that of Herz and his colleagues, who have explored the relationship between smell and autobiographical memory at a neural level.
Smell and emotions
The perception of smells consists not only in feeling them, but in the experiences and emotions associated with those sensations. Smells can provoke very strong emotional reactions.
In surveys of reactions to some odors, the answers show that many of our olfactory tastes are purely based on emotional associations.
Although there is compelling evidence that pleasant fragrances can improve our mood and feelings of wellness , Some of these findings should be considered with caution.
Some recent studies have shown that our expectations about an odor, rather than the direct effects of exposure to it, may be responsible for improvements in mood and health benefits that have been reported.
The effect of suggestion and placebo
In one experiment, the researchers found that simply informing subjects that a pleasant or unpleasant odor was being administered (which, they might not even be able to perceive) altered their self-reports relating to their states of mind and well-being.
Just mentioning a pleasant odor reduced reports related to poor health and increased reports related to a positive mood. These findings suggest that these improvements may be due to a placebo effect.
However, more reliable results have been found in experiments using Placebos In the form of sprays without any odor. These studies have shown that, although the subjects respond to some extent to odorless placebos of what they think are fragrances, the effect of the actual perfume is significantly greater.
Thinking about pleasant perfumes might be enough to be a little more cheerful, but the real scent can have dramatic effects when it comes to improving our mood and sense of well-being.
Although olfactory sensitivity is being lost as we age, it has been found that pleasant odors have positive effects on mood at any age.
The effects of odors on our perception
The positive emotional effects of smells also affect our perceptions about other people.
In one experiment, subjects who were exposed to fragrances that were pleasing to them tended to give higher"scores on attractiveness"over people appearing in photos that were shown to them.
However, some more recent studies show that these effects are only significant when there is some ambiguity in the photos. If the person in the photo is clearly very attractive or, on the other hand, extremely ugly, the fragrance does not usually affect our judgment.
However, if the person only has an"average level of attractiveness", a pleasant fragrance will tip the balance of our evaluation in your favor. In this way, the attractive models that are used to advertise perfumes probably do not need it, but the rest of us can benefit from a spray that smells good.
Unpleasant odors can also influence our perceptions and assessments. In one study, the presence of an unpleasant odor made subjects not only give worse scores to the individuals in the photos, but also judged some pictures that were shown to be less professional.
Positive odors can also have negative effects
The mood-enhancing effects of positive odors, however, sometimes play against us: increasing our perceptions and Positive emotions , Pleasant smells can cloud our judgment.
In an experiment at a Las Vegas casino, the amount of money earned on a slot machine increased by 45% when the place was scented with a pleasant scent.
In another study, a shampoo that participants had ranked as the ultimate overall outcome in an initial test, was ranked first in a second test after altering their odor.
In another test, participants reported that the shampoo was easier to rinse, applied better and made hair brighter. Only the fragrance of the shampoo had been changed.
Odor Preferences
Odor preferences are often a personal matter, having to do with specific memories and associations.
For example, in a survey the answers to the question"what are your favorite smells?"Included many odors that are generally seen as unpleasant (such as gasoline odor or body sweating). Nevertheless, Some smells normally perceived as pleasant (such as the smell of flowers) received very negative responses from some participants.
These preferences were explained by experiences (good or bad) that people had had and associated with particular scents. Despite the peculiarities of these individuals, it is possible to make some significant generalizations about olfactory preferences.
For example, experiments to date have shown that we have a tendency to like what we know: people give higher scores on how agreeable a smell they are capable of correctly identifying.
There are also some fragrances that seem to be perceived universally as pleasing, such as vanilla, an increasingly popular ingredient in perfumes that has long been a"standard pleasant odor"in psychology experiments.
A note for perfume merchants: one of the studies that show our tendency to prefer fragrances that we can correctly identify also showed that the use of an appropriate color can help us to make a correct identification, increasing our taste for perfume.
Cherry odor, for example, was more accurately identified when presented with the red color, and the ability of subjects to identify odor significantly enhanced their scores.
Smells and increased productivity
Have you ever considered perfuming your work space, your school or university? A priori may seem silly. However, odors can also affect labor productivity, in addition to influencing anemic states,
Rachel Herz notes that an increasing number of studies show that positive mood is linked to increased productivity, performance and the tendency to help others while negative mood reduces prosocial behaviors.
Notably, prosocial behavior and productivity are also enriched in the presence of pleasant environmental odors. For example, in an experiment, people who were exposed to the smell of biscuits in the oven or to coffee making were more inclined to help a stranger than people who had not been exposed to olfactory manipulation.
Also, people who worked in the presence of a pleasant-smelling air freshener also reported a Self-efficacy Greater at work. Further, Set goals And tended to employ more efficient work strategies than participants who worked in an odorless condition.
Pleasant environmental odors have also been found to increase the level of vigilance during a tedious task and improve execution in word completion tests.
On the contrary, the presence of odors considered as negative reduced the subjective judgments of the participants and lowered their levels of tolerance to the frustration. Participants in these studies also reported that they had had concordant mood swings.
Therefore, it can be concluded more or less safely that the observed behavioral responses are due to the effect of air fresheners on people's moods.
Some of the fragrances that seem to increase productivity at work are the smell of lemon, lavender, jasmine, rosemary and cinnamon.
So, you know: smells influence mood, good work performance and other forms of behavior, through learned associations, especially in an emotional way.