To enrich a child’s daily life, one should enrich their sensory experiences. To do this, it is important to value information that has not yet been able to be transferred digitally, such as the sense of smell, taste, and touch. That is what we talked about this time.
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Profile
Yati Obara
Editor-in-Chief, Scientific Montessori
Based in Japan, born in 1989. CEO of Motherhand and Co-Director of the nonprofit think tank Polymath Research. Holds an M.Eng. and is an AMI-certified teacher. Focused on Montessori developmental theory and AI. Mother of two.
Hiro Obara
Publisher, Scientific Montessori
Based in Japan, born in 1990. Works as a software developer and a weekend farmer. Father of two.
Create an environment that truly delights your child’s sense of smell.
Hiro
The theme is Practical Life, and when we talk about ages 3 to 6, it usually turns into “daily life is important,” “increase sensory experiences,” “let kids help in the kitchen,” but others have already said all that.
Yati
True. [laughs] So, continuing from the zero to three article, let’s dig deeper into the five senses.
Hiro
Sensory information can be broadly divided into two groups. In terms of sense organs, one group is the eyes and ears. The other is everything else: nose, mouth, and touch. Do you know the difference?
Yati
Sight and hearing versus smell, taste, and touch? Well, I don’t know.
Hiro
It’s like a “spot the difference” question. Eyes and ears are non-contact senses.
Yati
That’s true.
Hiro
Light and sound can be transmitted through TV or radio. But smell and taste, scents and flavors, can’t be transferred as information yet.
Yati
They can’t. You can’t express them digitally.
Hiro
You have to be there to experience them. Same with touch. MIT and others are working on it, but tactile sensations still can’t be transmitted. Smell, for instance, involves receiving chemical substances. And 90 percent of taste is actually smell.
Yati
So we’re mostly “tasting” through our noses.
Hiro
Right. That means smell accounts for two of the five senses. So today I want to talk about smell, specifically, about salmon.
Yati
The fish. Born in rivers, traveling the ocean, returning to rivers, an anadromous fish.
Hiro
Exactly. In Iwate, our prefecture in northern Japan, salmon swim upstream in the rivers. But recently, 97 percent aren’t coming back. Fewer and fewer return each year. Just like people.
Yati
When we moved to Iwate, I was looking forward to seeing salmon run upstream, but I still haven’t seen it. Why aren’t they coming back?
Hiro
The cause is unclear, but when people face problems like this, they blame climate change. There’s an atmosphere of “just say climate change.” A while ago it was COVID-19; now it’s back to climate change. Basically, blame anything but yourself.
Yati
Scientific Montessori not selling well in Japan must be climate change, too.
Hiro
Exactly. Blame that, and everyone nods, “Ah yes, of course.” Anyway, I’m contrarian, so I don’t buy it.
Yati
Right.
Hiro
I wanted to know how salmon actually find their way home, so I looked into it. For those unfamiliar: salmon are anadromous. They hatch from eggs in a river, head out to sea, and in Japan’s case spend about four years circling the Pacific before returning to the same river.
Yati
A four-year journey.
Hiro
Here’s what’s strange: rivers are freshwater.
Yati
Right. No salt.
Hiro
And the ocean is saltwater. Different osmotic pressures.
Yati
How does that work? For a human, it’d be like suddenly switching your drinking water to seawater every day. That’s a huge strain on the body.
Hiro
They go off on this intense warrior training. Remember when Shohei Ohtani, the baseball superstar, wanted to go straight from high school to the American Major Leagues? He was told the “osmotic pressure” was too high, so he joined a Japanese pro baseball team, the Nippon-Ham Fighters, first to acclimate to the pro world before heading to the majors.
Yati
[laughs] That’s right.
Hiro
So over about four years, salmon travel toward Alaska, up north, through the Sea of Okhotsk, the Bering Sea, off the coast of Alaska, spending four years training in America before returning. It’s called natal homing.
Yati
They go that far?
Hiro
About 30,000 kilometers over four years. They grow big. And their appearance changes. Beautiful as juveniles, almost delicate-looking, but they come back muscular, bulky, totally wild.
Yati
Of the fish, not Ohtani?
Hiro
Yes. Their faces and bodies become rugged. You can tell they’ve been through training. Surviving in the ocean is tough, with sharks and other dangers.
Yati
Yamame trout, a type of trout native to Japan, are also anadromous. Some stay in the river while others go to sea, and the difference is obvious. The ones that went to sea look truly wild.
Hiro
Right. They travel all that way and return home in glory to their hometown. So you’d wonder, “How do they find their way back?”
Yati
Seriously. Four years, all that distance, how do they remember their home river?
Hiro
Exactly. They’re not booking tickets like humans, flying from America, connecting through Tokyo, then taking a regional flight to our local airport. There are no signs in the ocean saying “200 kilometers to go.”
Yati
How do they do it? Maybe like migratory birds? Do they have an internal compass?
Hiro
That possibility has been suggested. The answer is: a magnetic compass and smell. The compass part is still hypothetical. They mainly rely on smell to navigate.
Yati
What do you mean? How could they smell something so far away in the ocean?
Hiro
Most people don’t know this, but fish choose paths and directions by smell. More than two-thirds of a shark’s brain is devoted to smell.
Yati
Really?
Hiro
That’s how they detect a single drop of blood from several kilometers away.
Yati
Scary. You shouldn’t go in the ocean with an injury. You’ll end up in Jaws.
Hiro
That ominous “duh-dun, duh-dun” theme from Jaws? It’s been playing for kilometers already. The shark knew there was blood and came looking.
Yati
Terrifying.
Hiro
Sharks are fish. Fish have incredibly powerful senses of smell. So if salmon aren’t coming back, the scent has either disappeared or been disrupted. They’re lost. And “Did they lose their sense of smell from COVID?” No.
Yati
So it’s not climate change or COVID.
Hiro
I doubt warming changes smells that much. My hypothesis: it’s synthetic chemicals. Fragrance compounds in laundry detergent and fabric softener. Scent compounds in chemical fertilizers and pesticides. Those accumulate in rivers and erase the scent of the salmon’s home.
Yati
That might be true.
Hiro
People return to their hometowns sometimes, right? If you have one. When you go back, there’s a smell. “Ah, that’s nostalgic.” Places have their own scent.
Yati
Absolutely. Smell is tied to memory.
Hiro
Smell carries an enormous amount of information, even if we’re not conscious of it. When you stay in one place, your nose adapts, and your brain stops actively perceiving it. But go somewhere different, and the smell is strong. India probably has an Indian smell; America has an American smell. Each place has its scent, a mix of food culture, climate, humidity, and more. If there’s this much variation within a single country like Japan, the natural world must be the same. It’s not strange that salmon remember and can distinguish the scent of where they were born.
Yati
I see.
Hiro
A hot topic lately is bears coming down from the mountains into human areas. Bears apparently have a sense of smell seven times sharper than police dogs. Yet people are running into them unexpectedly. It’s strange. Maybe strong synthetic fragrances are disrupting their noses. Maybe they can no longer detect “human scent.” That’s one hypothesis.
Yati
Losing a functional sense of smell is fatal for wildlife.
Hiro
For wild animals, smell is essential, for finding food and avoiding danger. Bears fear fire, and they can detect a distant fire by the smell of burning. Wildfires are the scariest thing for wildlife. They can avoid fire thanks to their sense of smell.
Yati
So, to bring it back: your hypothesis is that synthetic chemicals may be having a significant impact on wild animals’ sense of smell. There doesn’t seem to be research on this yet.
Hiro
Unfortunately not. Smell varies widely among animals. Their olfactory abilities and how they use them differ from humans. I gave examples of bears and fish, but the importance of smell differs for each species.
Yati
Let’s talk about smell for humans, specifically for three to six year olds.
Hiro
As I said at the start, sensory information divides into two categories. Eyes and ears can basically be satisfied by TV. But smell cannot. So the key senses are smell, taste, and touch. If you set up the environment to prioritize these three, it becomes harder to fake things. If you include sight and hearing when thinking about sensory environments, TV and digital media sneak in. But if you focus on smell, taste, and touch, you naturally avoid artificial chemicals. You move toward natural aromas, plant scents.
Yati
Real herbs, for example.
Hiro
If kids only eat chemical-laden snacks, everything tastes the same. They miss the variety within bitter, sweet, sour. By the way, limonene is apparently the strongest scent molecule in citrus.
Yati
It’s the most abundant fragrance compound in lemons. But natural things contain about 100 scent compounds, and subtle differences create nuanced fragrances. Children can probably distinguish them. In fact, there’s a pine tree called Japanese red pine that contains limonene, and my eldest daughter noticed it smells like lemon.
Hiro
So my point is that artificial, tasteless and odorless Montessori materials alone aren’t enough.
Yati
There’s something called the smelling bottles, small opaque jars with aromas or herbs inside. You prepare pairs with the same scent and children match them. But that alone isn’t enough.
Hiro
Instead of buying herbs, grow them yourself.
Yati
We grow various herbs in planters in front of our house. We grow them, harvest them, play scent-guessing games, use them in cooking, steep them in hot water for herbal tea, and lately we’ve been adding the brew to the bath for a medicinal soak. We’ve even made potpourri.
Hiro
Right. And incense, too, real sandalwood. Creating an environment that delights the sense of smell in many ways is part of living a more intentional life. If you’re familiar with natural scents, you’ll notice when something smells chemically off.
Yati
As I mentioned, natural fragrances contain many compounds. To recreate a rose scent in perfume, you need floral notes, woody notes, citrus notes, many elements.
Hiro
True. And building vocabulary around that helps. Terms like “woody” and “floral” exist, but the natural world is broader. Even within citrus, plants differ. For instance, Japanese pepper, called sansho, is in the citrus family. That sansho aroma comes from citrus origins. The spiciness of sansho berries and the sourness of citrus belong to the same family. This connects to cooking. That’s why sansho pairs well with strawberries.
Yati
That’s interesting.
Hiro
It seems odd at first, but it’s the same principle as strawberries going with oranges.
Yati
Like the idea that foods grown in the same place during the same season taste good together.
Hiro
Vegetables grown naturally are different even at the chemical level, phytochemicals. The smell and flavor differ. If you train your nose properly, you start noticing these things.
Yati
I think children have incredibly sharp senses of smell and taste. They say “It stinks!” right away. [laughs] They love meat braised in red wine, and adding just a little cardamom changes how eagerly they eat curry. Oh, spices are another way to enrich the olfactory environment at home.
Hiro
Cumin and coriander aren’t spicy, so they’re easy to use. Spices let you enjoy combining scents, and they can boost immunity. In old Europe, there were medical professions focused on creating pleasant scents.
Yati
Health conditions show up in body odor, so noticing your child’s scent is important. Strong artificial fragrances might mask that.
Hiro
Smell alone is incredibly deep. Summing it all up as “increase sensory experiences” says almost nothing. What I wanted to convey today is: “Create an environment that truly delights your child’s sense of smell.” And returning to the beginning: salmon remember something from four years earlier. From their perspective, a “distant memory” of early life. Their home scent has changed, and they can’t find their way back. Salmon who can’t return home. It’s sad.
Yati
It is sad.
Hiro
People think if they release lots of fry, salmon will come back upstream, but maybe the cause lies elsewhere. Humans need to reduce the synthetic chemicals we produce. We need to cherish the beautiful chemicals that nature creates. They may seem similar, but they’re fundamentally different.
