Shortly after finishing my article on wayfinding, I read another book, this time about the sense of smell. I assumed they weren’t particularly related. Wrong. Jonas Olofsson, author of The Forgotten Sense: The New Science of Smell – and the Extraordinary Power of the Nose, picked up the trail after I left off. (Sorry, but smell science lends itself to puns.) He thinks the nose is underrated.
That’s one of the things that they’ve been testing. How accurate is the human nose? Way more than we’ve all been told! Of some 20 animal species that had been tested, human noses were more sensitive to odor molecules than most other animals.
“Humans were more sensitive than other animals to the vast majority of odor molecules. Human versus rat: 31 to 10. Human versus mouse: 36 to 35. Human versus vampire bat: 14 to 1. Human versus spider monkey: 58 to 23. The only animal that was clearly better than humans was the dog, which is more sensitive to 10 out of 15 odor molecules.” (17)
They even had people down on all fours following scent trails in the grass. You actually could try this at home, I guess. Just don’t snort the dirt up your nose … and make sure you have an alibi in case the neighbors see you!
But we don’t usually navigate on all fours. So, what does smell have to do with wayfinding? For starters, smells are linked to memories. And memories are part of narratives that we have in our brains.
“It is now well established that smells have a unique capacity to evoke memories of childhood. But that is not all. Olfactory memories are also different in other ways. They evoke a sense of “going back in time” in a way that no other sensory experience does. Smells can make you relive the time you helped your grandfather tar the rowing boat, the time you stepped out of the airplane on your first vacation to the Mediterranean or the wedding where you got to be a bridesmaid with your own bouquet of flowers. You remember the details, relive the moods. Smell memories are also more emotional than other memories.” (71)
Wayfinding and memory are both processed by the same part of the brain, the hippocampus. So, it is no surprise then that memory and wayfinding are both affected by dementia, which often affects the hippocampus early on in Alzheimer’s Disease. The hippocampus is part of the medial temporal lobe (MTL).
“We now know that the disease often starts in the regions of the medial temporal lobe and lower frontal lobe, both of which process smells. These regions also control memory storage, so the loss of smell combined with memory loss is particularly ominous.” (145)
Our narrative sense of our own history, our map of the past, is tied to our sense of smell. But what if that sense of smell becomes degraded? Alzheimer’s is known for affecting the sense of smell, but so is COVID. Ah, now you’re listening, because you might be one of many younger people who lost their sense of smell due to the pandemic. Sometimes it comes back on its own, but sometimes there are lingering problems. Is there anything that we can be doing for ourselves or our residents?
We’ve all seen the brain exercises using picture cards which the player must name from memory. Olofsson’s group came up with a smell-based memory game. They had players use it for 40 days, and saw clear improvements in smell detection. But they also saw improvement in the ability to identify things visually – even though that was not part of the game.
“But the most interesting result was found when we tested the memory games themselves, both visual and olfactory. Those who had played the regular visual memory game became very good at it after the training program. The same applied to those who had played the smell game … and they also got better at the visual memory game! However, those who played the regular picture memory game did not improve at all on the smell game or any other smell task. So by replacing images with smells, we were able to promote improvements in several different tasks.” (149)
What is his advice? Get the most bang for your brain-training buck. Don’t just use visual games, but use ones like smell training that target more than one skill.
“One area of the cortex of the parietal lobe may have even grown slightly thicker in those who trained with smells and learned to get better at both olfactory and visual tasks. This area is known to help us with spatial understanding, navigating [emphasis mine] and remembering where things are located in our environment. Training the ability to remember where the matching odor pairs were placed would now make this brain area more connected to the frontal lobe, which decides our movement patterns.” (150)
There are commercially available scent games on the market or you can Google Jonas Olofsson to watch some of his YouTube videos for more information.
© Donna Stuart, ADC, MT June 23, 2025
Olofsson, J. (2025 translation). The Forgotten Sense. New York: Mariner Books.
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