Bill Hansson, scent expert: “Don't buy pheromones to try to get laid, it doesn't work. Better work on your personality”

The world a thousand years ago was very different from today, also for our sensory perception.

A landscape without planes, cars or ships, and, of course, without industry, smelled beyond recognition to a modern human.

Something as complicated as understanding how they perceive the olfactory world in the rest of the animal kingdom thanks to their millions of years of adaptation to habitats.

With this framework, the director of the Max Planck Institute for Chemical Ecology, Bill Hansson (Jonstorp, Sweden, 63 years old), publishes

(Criticism, 2022), about a sense almost always ignored.

The neuroethologist, specialized in insects and their interaction with plants, goes through the complex sensory mosaic that results from olfactory capacity in the animal and plant world.

Of which humans are only a small part.

Hansson issues a warning about the future: pollution from the Anthropocene has already changed chemical dynamics of animal and plant ecosystems with future consequences that we cannot foresee.

Ask.

What is it about the smell, that chemical process, that affects humans so much?

Response.

The smell is really special because it's multidimensional, that's what's great.

When we think of seeing or hearing, it is the same type of wave, right?

For different colors or sounds.

But when it comes to scent, each molecule is different and unique.

You have 350-400 receptors in your nose to smell.

They are like the keys of a piano, imagine what you could do with so many possibilities, how many melodies could you play?

If they are combined in different ways, it could be millions.

And that's exactly what you can smell.

More information

Human smell is no worse than that of dogs for some odors

Q.

We still don't know the exact process?

R.

We don't know everything.

There are a lot of molecular processes going on, it's the domain of neuroscience.

Although we have some ideas of how it works.

The odorous molecules are all around us and reach your nose, which is a receptor, like a key that goes into a lock, triggering a whole neurochemical process.

The olfactory epithelium is the only place where the nervous system is in direct contact with the environment, I am talking about millions of receptor cells embedded in the mucosa.

There the information, which is a chemical signal, becomes electrical and travels through the olfactory nerves to the brain.

Taking a detour, it goes to the next level, it reaches the limbic system, where the hippocampus —we know it is extremely good at evoking memories— and the amygdala —very involved in emotions and sexuality— are.

The nose, the only place where the nervous system is in direct contact with the environment, has 350-400 olfactory receptors: millions of odors to detect

Q.

Nothing is comparable to the regression caused by an aroma, perhaps music.

A.

Probably because it is a very old sense.

Maybe the first one we had, so it's really deep in our brain and connected to all functions.

Q.

Something that, you explain, extends to the rest of the animal world, where smell is mainly the plane of reality in which many species move.

R.

There are animals that interpret the smell in a different way, because they are a thousand times more sensitive than us and we will never be able to understand it.

If you walk with a dog in a city park every day, the same route becomes very boring for you, but for the dog every day is new.

With his developed nose he can see the past, detect other animals, he captures a whole story that has stayed there because the smell persists for a long time.

A fruit fly ('Drosophila melanogaster') in an experiment by Bill Hansson.ANNA SCHROLL

Q.

So, how we perceive the world also limits us compared to other animals?

Do we not access all reality?

A.

How an animal perceives reality through the senses in its habitat is called an

, and we are all limited.

Even if we live in the same environment as a dog, our brain does not understand its sensory world.

A sense of smell developed with a sensitivity of some capacities, such as smelling a corpse submerged 20 meters under water or that a moth detects the equivalent of minute concentrations of a sugar cube diluted in the Mediterranean Sea.

Birds and fish, along with many different species, use scent as a reference when moving.

We cannot understand that, and that is why it fascinates us.

Q.

An ability so ancient and primitive, you point out, that it has arisen at different evolutionary points several times and in different ways because of its usefulness.

A.

Yes, exactly.

We call it a convergence in evolutionary terms.

An ability that probably comes from different starting points in the species, but in the end it has become similar because it has to solve the same thing: pick up molecules and go to the brain to interpret it and then cause relevant behavior.

A tobacco moth ('Manduca Sexta'), as a model animal in the work of Bill Hansson of the Max Planck Institute for Chemical Ecology.ANNA SCHROLL

Q.

The automatic ability to access forgotten memories, you mention in your paper, can be inconvenient, especially in cases of post-traumatic stress.

A.

Yes, of course, you can activate it by unconsciously recalling a bad memory.

A smell can trigger anything, it transfers you to a place regardless of where you are without you being able to do anything against it.

Q.

And despite being something so special, he explains, are we incapable of describing a fragrance?

R.

True, when we try it we always do it via comparison.

We say “it smells like banana, vanilla or… like shit”.

We lack words to do it, but it is also something cultural.

We did experiments with Malaysian natives and they have specific words for the most important smells.

For example, to warn of the presence of a tiger through its feces or urine.

It is vitally important to warn of danger and you don't have time to say, “Oh, it smells like a tiger”.

They mention it and they know they have to get out of there.

Due to the loss of smell, and taste, caused by covid-19, people realized how much it means to the quality of life

Q.

A forgotten perception that we do not value until we lose it, as happened during the covid-19 pandemic, when we began to talk about anosmia, the total loss of smell.

R.

Before there was a general interest in smell, simple curiosity about this mysterious sense.

When the cases appeared due to the pandemic, even if smell recovered by 90%, people realized how important it is because taste is also lost.

We understood how much it means for the quality of life to be able to smell.

Q.

"If you lose it, you lose the best of life," he writes.

A.

Exactly.

Everything hedonistic, like good food and drink or good sex, depends a lot on smell.

There are a lot of olfactory interactions, all of this is connected and when something is gone, that's a bad sign, because you can't really enjoy it like before.

With your partner and children, much of the smell merges into a common aroma when you live together.

You recognize and like that very strong chemical bond, you feel safe and loved.

By losing that ability to feel it, relationships can even be broken.

The most likely cause of death for people without smell is due to gas or eating spoiled food

Q.

A sense that can disappear, as you explain, also when you suffer from other neurodegenerative diseases.

A.

The complete loss of smell, or even a pronounced deterioration in the ability to smell, is one of the first signs that something is wrong.

Today it is used as an early diagnosis for Alzheimer's and Parkinson's.

It is reasonable to think that there is a link between the olfactory sensory nerves and the cerebrospinal fluid, which bathes the entire brain and spinal cord, and which is responsible for cleaning waste from cells via the mucous glands.

If it presents any type of damage, it could trigger a domino effect with neurological consequences.

Q.

Death from anosmia?

R.

The loss of perception is a brutal cut in our existence, it affects mental health and makes us feel truly lost.

The olfactory system is a chemical gauge of quality and also of danger.

Constantly monitor our surroundings with every breath you take.

If it detects smoke at night, it alerts you.

Just like with rotten food.

The most likely cause of death for people with olfactory loss is gas or eating spoiled food.

Professor of evolutionary neuroethology and director of the Max Planck Institute for Chemical Ecology, Bill Hansson.

Anna Schroll

Q.

The obsession with manipulating the human smell, you describe, generates an industry, the perfume sector, which oscillates between 50 and 90 billion dollars.

Is it all vanity, to hide our stench and seek pleasant sensations?

R.

It is an ancient tradition, there are records in India, Egypt and Mesopotamia, but as a sector it reached its peak in the 18th century at the hands of the French King Louis XV and Madame Pompadour, who promoted a fashion that everyone signed up for. .

Noble people tried to differentiate themselves from the populace by smelling different.

And then the whole perfume industry was invented.

Today it is one of the largest industries in Europe, the flagship being the International Flavors and Fragrances Consortium (IFF), which markets scents not in tiny vials, but in tankers.

A multi-million dollar business to make things that make us smell like something other than ourselves.

Of course we have pheromones, but we also have cultural and emotional baggage.

Humans are animals and we are moved by sex, but we are complex

Q.

You actively discourage the purchase of any product that promises to get you a partner or sex simply by spraying your entire body, or just parts of your body.

R.

It does not work.

And I want to be very clear and express myself correctly so that I can be understood clearly [smiles]: of course we have pheromones, I know we do, but we also have many other things.

We are complex.

When a female dog is in heat, it emits pheromones to a male dog, an unequivocally sexual signal, both only think about mating.

They forget about everything else.

They seek to have sex as soon as possible and as quickly as possible.

If we go further, to the insects, it is even more pronounced.

Humans are animals, too, and we are moved by sex, but we will never be like that.

We will always have many, many other things that affect us from childhood, a whole emotional baggage, what you have experienced.

That is, other animals do not reflect much on what happened last year, only on the new mating season.

But we are going to ruminate on anything that has happened to us previously, perhaps a bad experience with another person before.

There are people who try to sell you artificial pheromones over the internet in order to manipulate you... It doesn't work.

People are extremely complicated creatures, it takes a lot more than a smell to drive someone crazy.

Maybe you better work more on your personality.

Researcher Bill Hansson's wood beetle forest fieldwork, courtesy of the Max Planck Institute.ANNA SCHROLL

Q.

You dedicate a chapter to the smell of the future, detailing what happens through the Anthropocene, to what extent is it changing ecosystems, also at an olfactory level?

A.

When we talk about environmental problems, the industry uses dimethyl sulfide, for example, which is plastic that, when decomposed, gives off an aroma similar to that emitted by areas with a large amount of fish.

The problem is that the decomposing plastic in the middle of the ocean is ingested by albatross, turtles, seals or whales;

they just eat it all the time because it smells like their regular food.

We know that ozone in the upper layers of the atmosphere protects us from the sun, but down here it's

.

In an experiment that we carried out, we verified how it modified the aroma of a flower.

In a contaminated area, what it gives off is so different that the insect no longer recognizes it and does not carry out the pollination cycle.

Change all the smells and get the molecules that surround us to become different.

In this way, it becomes a new olfactory world.

Q.

Why when we imagine the future in virtual worlds, we never notice the smell as another immersion mechanism?

Virtual reality headsets rarely stimulate the nose.

R.

I agree, it is a missed opportunity.

But it is not only the future, there are already consumer products that use sensory

, the smell of a new technological product when unpacking it or a brand new car, or when the bakery connects its ventilation ducts to the street.

A full virtual reality should take all the senses into account if you really want to achieve total immersion.

You can follow