Scientists believe that the sense of smell and memory are closely related, because the anatomy of the brain allows olfactory signals to reach the limbic system very quickly, the part of the brain responsible for our behavioral and emotional responses.
In an article for the Very Well Family website, author Claire Gilesy says that memories associated with smells tend to be older and less thought of, but at the same time smells can still evoke memories.
Childhood memories are most closely associated with smells, such as the smells of food the mothers cooked, because our 'smells of happy memories' are more associated with the early years of life, while memories associated with verbal or visual information originate in early adulthood.
"People often say that the sense of smell evokes memories so well that they feel as if they are experiencing the event again," the author quoted Theresa L. White, professor and chair of the psychology department at Le Moni College in "Syracuse-New York", as saying. For example, make them feel like they are back home, enjoying a delicious meal."
She said several studies have looked closely at the relationship between smells and strong memories.
A study, published in Progress in Neurobiology, identified a neural basis for how the brain enables smells to evoke strong memories.
Researchers from the University of California, Irvine, discovered specific types of neurons within the brain's memory center that are responsible for acquiring new associative memories, i.e. memories generated by unrelated components, such as smell.
There are certain types of neurons within the brain's memory center that are responsible for acquiring new associative memories (Getty Images)
The olfactory system and the brain
The author also quoted Pamela Dalton, a professor of experimental psychology at the Monell Chemical Senses Center, as saying that their experience with smells is usually when the smell is the background or context for a person, place or emotional state.
When these events are significant or memorable, the smell can be so closely linked to memory that re-experiencing the smell often leads to a revival of old feelings and memories associated with it.
The association of emotional memory with smell appears to be stronger than other sensory experiences, due to the smell's ability to reach the central brain structures of the brain's olfactory system, which share the same area responsible for regulating feelings and emotional memories.
Smell associated with memory subconsciously revives old feelings and memories associated with it (Getty Images)
A special kind of memory
A 2010 study published in the American Journal of Psychology found that memories associated with scents tend to be more emotionally arousing.
The author credits L. White as saying that associative memory can function with any sense, and smell is no exception.
"Imagine always relaxing in a hot lavender-scented bubble bath at the end of the day, you'll associate the scent of lavender with a feeling of relaxation. This means that over time, when you smell the lavender and aren't in the bath, you'll still feel relaxed."
Scent-related memories tend to be more emotional (Getty Images)
The power of smell
The researchers found that smells can act as a memory stimulant, increasing our ability to remember or recognize information.
In Professor Dalton's graduate study, she had people study strangers' faces in the presence of different scents.
She revealed that the best recognition performance occurred when they were tested with the same smell that was present when they first saw those faces.
A number of other studies have confirmed similar findings, meaning that studying in the presence of a scent can help an individual remember that information.
Perhaps the association of infection with the Corona virus “Covid-19” with loss of sense of smell leads us to hypothetically expect memory problems, but so far, no one has specifically studied memory among individuals who lost their ability to smell after infection with the virus.
"Deterioration of the sense of smell is associated with cognitive impairment, but this is because central structures involved in the sense of smell can be affected by neurodegenerative diseases," says Dalton.
We may hope that over time we will have an understanding of all the ramifications of loss of smell and the impact on cognitive and emotional aspects, including memory.