Table of Contents
Last updated on January 5, 2023 byMike Robinson
Theolfactory memoryrefers to the memory of smells. Scents can bring back many memories. This is because the olfactory bulb, which is an area 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 emotion, smells can trigger memories and trigger strong reactions almost immediately.
How is the relationship between smells and memories formed?
The theospheric bulb accesses the amygdala, which processes emotions, and the hippocampus, the structure responsible for associative learning. Despite the connections between the structures, odors would not evoke memories if it were not for the conditioned responses formed over time.
Smelling Memory
When you smell something for the first time, you unconsciously associate it with an event, a person, an object, a moment or a place. Your brain makes a connection between the smell and a memory, and for example associates the smell of chlorine with summer or the smell of lilies with funerals.
When you find yourself with the smell again, the bond is already established and ready to trigger a memory or even a level of mind. The smell of chlorine can make you feel happy because it reminds you of summer times by the pool with your friends.
However, lilies can make you inexplicably melancholy. This is partly why not everyone prefers the same scents: by pure association.
Since we find most of our new smells in our childhood and youth, smells often evoke childhood memories. But we actually start making associations between smells, feelings and memories before we're even born.
Children who have been exposed to alcohol, cigarette smoke or garlic in the womb often show a preference for these smells. To them, smells that may bother other babies seem normal or even pleasant.
Amygdalas rolle
The amygdala is an almond-shaped brain structure that processes everything related to our emotional responses. It is one of the most primitive areas of the human brain.
It is also associated with memories and memory in general, as many of our memories are related to some emotional experiences.
A decade ago, Rachel Herz, an expert in the psychology of smell, and her colleagues at Brown University investigated whether there was a correlation between the emotional intensity of an odor-evoked memory and the activation of the amygdala.
The participants first of all described a positive memory triggered by a particular scent. Next, they went to the lab to participate in a functional magnetic resonance experiment.
Participants were exposed to different sequences of visual and olfactory stimuli. Visual stimuli included a picture of the participant's chosen odor and a picture of an unlabeled odor. The olfactory stimulus included the participant's chosen odor and the unlabeled odor.
If the stimulus evoked a memory or emotion, participants were asked to hold it in their mind until the next stimulus was presented.
When participants smelled their chosen scent, they showed greater activation in the amygdala and parahippocampus (an area surrounding the hippocampus).
These data suggest that odors that evoke emotional and intense memories also cause high activity in brain regions strongly associated with emotion and memory.
However, it is important to know that this study only involved five people and that they were all women. Studies with a larger sample of participants, including men and women, are needed to confirm these findings.
Several behavioral studies have shown that smells evoke more vivid emotional memories and are better at evoking that feeling of being "transported back in time" than images.
However, there have been few studies, apart from that of Herz and colleagues, that have explored the relationship between olfaction and autobiographical memory at the neural level.
Smell and emotions
Perceiving smells is not just about feeling them, but about the experiences and feelings associated with those senses. Smells can cause very strong emotional reactions.
In research conducted on reactions to certain odors, the responses show that many of our olfactory tastes are based solely on emotional associations.
Although there is compelling evidence that pleasant scents can improve our mood and sense of well-being, some of these findings should be taken with caution.
Some recent studies have shown that our expectations of an odor, rather than the immediate effects of exposure to it, may be responsible for the reported mood improvements and health benefits.
Cues and placebo effect
In one experiment, researchers found that simply informing subjects that they were smelling a pleasant or unpleasant smell (which they might not even be able to perceive) changed their self-reports of their mood and well-being.
Simply reporting a pleasant smell reduced reports related to poor health and increased reports related to positive mood. These results suggest that these improvements may be due to a placebo effect.
However, more reliable results have been found in trials with placebos in the form of an odorless spray. These studies showed that although subjects respond somewhat to odorless placebos that they perceive as scents, the effect of the actual scent is significantly higher.
Thinking about lovely scents can be enough to make us a little happier, but the smell itself can have dramatic effects when it comes to improving our mood and sense of well-being.
Although the sense of smell is lost as we age, pleasant smells have been shown to have positive effects on mood at all ages.
The effects of smells on our perception
The positive emotional effects that smells have also affect our perception of other people.
In one experiment, people exposed to pleasant scents tended to give higher "attractiveness ratings" to people who appeared in pictures shown to them.
However, some recent studies show that these effects are only significant when there is some blur in the photographs. If the person in the photo is clearly very attractive or, on the contrary, extremely ugly, the smell usually does not affect our judgment.
However, if the person has only a "moderate level of attractiveness", a pleasant scent will tip the balance of our judgment in your favor. That way, attractive models used to advertise perfumes probably don't need it, but the rest of us can benefit from a spray that smells good.
Unpleasant smells can also affect our perceptions and judgments. In one study, the presence of an unpleasant smell led subjects not only to give poorer ratings to people in photos, but also to rate certain designs as less professional.
Positive smells can also have negative effects
However, the mood-enhancing effects of positive smells sometimes work against us: by increasing our perceptions and positive feelings, pleasant smells can cloud our judgment.
In an experiment in a Las Vegas casino, the amount of money won on a slot machine increased by 45% when the area was scented with a pleasant aroma.
In another study, a shampoo that participants had ranked last in terms of overall efficacy in an initial test was only placed in a second test after it changed smell.
In another trial, participants reported that the shampoo rinsed out more easily, applied better, and left hair shinier. Only the scent of the shampoo had changed.
Smell preferences
Scent preferences are usually personal, tied to specific memories and associations.
For example, in a survey the answers to the question "What are your favorite smells?" It included many odors that are generally considered unpleasant (such as the smell of gasoline or body sweat). However, some scents that are normally considered pleasant (such as the scent of flowers) elicited very negative responses from some participants.
These preferences were explained by the experiences (good or bad) people had and associated with particular smells. Despite the idiosyncrasies of these individuals, it is possible to make some important generalizations about odor preferences.
For example, experiments so far have shown that we tend to like what we know: people give higher ratings to how pleasant an odor they can correctly identify.
There are also certain scents that seem to be universally perceived as pleasant, such as vanilla, an increasingly popular ingredient in perfumes that has long been a "standard pleasant smell" in psychological experiments.
A note to perfumers: one of the studies showing our tendency to prefer scents we can correctly identify also showed that using an appropriate color can help us make a correct identification, increasing our liking for the scent .
The scent of cherry, for example, was recognized more accurately when it was presented in red, and the participants' ability to recognize the scent significantly enriched the ratings they gave.
Odors and increased productivity
Have you ever thought about perfuming your workplace, school or university? A priori it may seem silly. But smells can also affect work productivity in addition to affecting mood,
Rachel Herz notes that a growing number of studies show that positive mood is associated with increased productivity, performance and a tendency to help other people, while negative mood reduces prosocial behavior.
Notably, prosocial behavior and productivity are also enhanced by the presence of pleasant environmental odors. In one experiment, people who were exposed to the smell of cookies in the oven or coffee being made were more likely to help a stranger than people who had not been exposed to odor manipulations.
Similarly, people who worked in the presence of pleasant-smelling air fresheners also reported greater self-efficacy at work. Furthermore, these targets and tended to use more effective task strategies than participants working under odorless conditions.
Pleasant ambient odors have also been shown to increase levels of alertness during a tiring task and improve performance on word completion tests.
In contrast, the presence of odors perceived as negative reduced participants' subjective ratings and lowered their levels of frustration tolerance. Participants in these studies also reported experiencing frequent mood swings.
Therefore, it can more or less safely be concluded that the observed behavioral reactions are due to the effect of air fresheners on people's mood.
Some of the scents that seem to increase productivity at work are the scent of lemon, lavender, jasmine, rosemary and cinnamon.
So you already know: smells affect mood, good work performance and other types of behavior through learned associations, especially emotional ones.