'Vivaldi smells like breakfast sausage'

Smell can trigger memories and influence emotions. New research is giving us insight into how that happens, including why some people can "smell" music and why losing the sense of smell can alert us to what might make us sick.

Jonas Olofsson, professor of psychology at Stockhom University. Director of the Sensory Cognitive Interaction Lab. Author of "The Forgotten Sense: The New Science of Smell and the Extraordinary Power of the Nose."

Excerpt from "The Forgotten Sense: The New Science of Smell and the Extraordinary Power of the Nose." All rights reserved. Not to be reprinted without permission.

Part I

MEGHNA CHAKRABARTI: Our sense of smell is determined by about 400 olfactory receptors. Some estimates indicate those receptors could detect up to a trillion smells. However, even though we rely on our sense of smell during every waking and sleeping moment, out of all the five senses, the sense of smell has often been ignored as a valid research subject by the scientific community.

At least, that's according to psychology professor Jonas Olafasson. He directs the Sensory Cognitive Research Lab at Stockholm University in Sweden, and he's author of The Forgotten Sense: The New Science of Smell and the Extraordinary Power of the Nose. Professor Olafsson, welcome to On Point.

JONAS OLAFSSON: Hi, Meghna.

It's nice to be here. Thank you so much.

CHAKRABARTI: First of all, before we talk about the science of this particular sense, I'm curious what got you into this line of research, if it's also been historically so ignored as you say.

OLAFSSON: Yeah, so when I was a student, I was working as a nursing assistant. And at the same time, I was studying cognitive science at the university.

And so I met a lot of older folks in the early stages of dementia. So I could see what affects that disease had on people. And at the same time, I learned that the sense of smell was emerging as an early marker for detecting Alzheimer's disease in early stages, so I set out to study that for a PhD, and that's how I got into the sense of smell.

It can tell us a lot about the status of our brains and how the brain is doing in old age, and that's been a topic of research for me ever since.

CHAKRABARTI: Can you tell me a little bit more about the relationship, of sense of smell to Alzheimer's? Because as soon as you said it, I thought, wow, people are going to want to know if it is truly an early indicator.

OLAFSSON: Yeah. So what we and others have found is that these tau protein accumulations that are the hallmarks of this disease, they don't emerge in all parts of the brain at the same time. So they appear in certain regions more than others. And the regions related to memory encoding.

So encoding of memories, retrieval of memories, but also processing of smells, those are among the regions that are affected in the very early stage of the disease. And that's why tests of memory and tests of smell and tests of memory for smells. Those are the most sensitive to pick up these very early pathology signs, but one should also think about it in this way.

There are other ways that the sense of smell can be affected by other types of diseases, for example, COVID. So it doesn't mean necessarily that a bad sense of smell is a warning sign, but rather that those of us who have a good sense of smell might see that as a positive sign that we are not likely to develop dementia anytime soon.

CHAKRABARTI: Okay. I want to keep, put a little pin in the idea that the regions of the brain that process smell and encode memory are quite similar. We'll come back to that a little bit later. But I want to play a little bit more from our listener, Shauna Martin, who's in Austin, Texas, because her whole story about her passion for a particular smell is a really good way to set us up for real world questions.

Why isn't it studied as much as, say, vision, of course. So Shauna told us that she used to get in trouble at daycare when she was a little child because she would smell and taste mud. Actually, Shauna, it doesn't seem all that unusual to me. A lot of kids do that, so too bad your daycare instructors didn't let you do that.

But she says she never understood why other people weren't as attracted to the scent as she was, and in fact, as she grew into adulthood, the smell of mud is something that shaped her life as well.

SHAUNA MARTIN: Anyway, I've always enjoyed the smell that comes right before, right after the rain, when the pavement is wet.

And now I am a ceramic artist, and I've noticed that when clay dries on the surfaces in my studio when I'm cleaning it and I re-wet it, emits that same smell and a friend of mine recently acquainted me with the term Petrichor, which is the word for that smell and it's a mix of soil bacteria and ozone. And I wish I could bottle it.

CHAKRABARTI: That's Shauna in Texas.

So Professor Olafsson, if indeed smell, the way people responded to us when we said send us your stories, they responded from a very primal place, right? It's like smell actually carries great importance in their lives. Then why have scientists and philosophers historically discounted it as a valid area of thought and research as you state in the book.

OLAFSSON: Yeah, that's a really good question. And I think that as scientists, we tend to gravitate towards those things that are objective and objectively measured. And it's been hard to measure a smell and the impact that the sense of smell has on us, is very, might seem very idiosyncratic.

We have personal memories. We have strong revulsions or attractions related to certain smells. And these examples that you played beautifully illustrates that. But I think that is has made it seem as subjective and maybe not possible to pin down with modern science.

So at least that, I think that's a prejudice that researchers have had against the sense of smell.

CHAKRABARTI: When you say modern, do you mean 20th century, 21st century? Or do you mean Enlightenment era modern? What do you mean?

OLAFSSON: Yeah. So there are historians that argue that the scientific revolution in the 1600s.

Made a kind of a cultural shift towards the visual sense as the most, quote-unquote, objective sense. And that we live in the age of vision and of course nowadays, it's even more so than it was before, with our screen-based kind of culture. So I think that we live in the age of the eye, so to say, and I think.

We need to get back to understanding the chemical senses better. Because they do shape our lives in a myriad of important ways. And that's what I've been trying to capture, basically.

CHAKRABARTI: What about, since 1600s, that's a really interesting time period, right? Because you have both the quote-unquote modernization of science, as you're saying, but it's still done in a world that's dominated by religion, right?

And I do wonder if there's, you write about this in the book, that there is a sense that, sorry, I don't mean, I will try not to use too many puns. But there is a sense that because of, let's say, humankind's spiritual desire to separate ourselves from the animal world, that also propelled some of this.

OLAFSSON: Yeah, and there is a story about Paul Broca was a pioneering scientist of the brain. And he argued that the sense of smell was the most primitive of the senses, and that it had been overshadowed in the human brain. It was overshadowed by the frontal lobes. So that's where he argued that the more reasoning abilities and language abilities resided.

So the olfactory lobes, as you call them, were atrophied and that we were not very good smellers. And there were more primitive animals that were, they were guided by their noses, basically. So that has been also a scientific prejudice, that the more kind of intellectual capacities came at the expense of smell.

But I tried to turn that around, and I think that there's enough research now where we can say that the sense of smell and taste, the reason why they influence us so much, is because those senses tie together cues from all other senses and also from our memories, our concepts, our knowledge base.

And we can, we have a very rich appreciation of flavor. If we really attend to these, to the stimuli, it's just that we haven't really realized that in research. But I think people who are foodies and into wine tasting, they know this already, but science is beginning to catch up.

CHAKRABARTI: It's so funny because these same scientists eat food all the time. And they don't even think about it, but they're very stimulated by whether something smells good or bad. But going back to Broca, I'm wondering if there was also oftentimes in this particular era of science researchers had to make let's say modifications to what they wanted to study in order to appease the church.

To keep the church out of their business. Was that part of Broca's motivation?

OLAFSSON: Yeah, very much and the idea that we would study the brain of humans and other animals and compare those, that could be seen as controversial in the 1800s where Broca was doing his work.

So this was a way to maybe balance that kind of political landscape, to find a way to tell people that the human brain is really different from all other animals and those more primitive animals. They are driven by what they smell, whereas we are driven by reason and to the extent that we're driven by sensory cues.

It's about what we see, and possibly what we hear and communicate through language. So the higher senses and the frontal lobes, they were emphasized. Other animals should not be conflated with humans. There is no kind of, there is a strict boundary between us.

Part II

CHAKRABARTI: Here's a couple of more of the really interesting stories that listeners shared with us about what their noses know.

This is Andrew from Belmont, Massachusetts. And of course he points out that, look, we might want to talk about the lovely aromas of our life, but not every smell is a good one.

ANDREW: I guess my most common experience with smell is car exhaust. And I hate the smell, probably bad for us. I wish there was less of it.

CHAKRABARTI: Agreed. Andrew, we'll talk about the function that bad smells serve in our lives in a bit. Here's Ed in Atlanta, Georgia, and he actually has a pretty unusual relationship to his sense of smell. Because Ed tells us that for him, smell can't always be separated from his other senses.

ED: Decades ago, I was attending an evening jazz performance on the Spelman College campus.

In the midst of a particularly discordant piece of music, I found myself awash in an indescribable scent. I looked left and right of me, saw no one else sniffing the air, and realized I was experiencing synesthesia. I was smelling the music. It happened again to me years later, during a broadcast of the Vivaldi guitar concerto and another time or two since.

I got a decent poem with the sax from the first experience, and I can tell you that Vivaldi smells to me like breakfast sausage cooking.

CHAKRABARTI: (LAUGHS) Ed, thank you so much. That's from Atlanta, Georgia. So Professor Olafsson, when you said that smell can help us understand the status of the brain. Where in the brain are we first sensing whatever signals are sent from the nose?

OLAFSSON: So the molecules that we inhale interact with receptor neurons in the top of the nasal cavity. So inside the nostrils. And there, the nervous system is exposed in the epithelium and that's where the signal starts to be translated to an electric code, and the neurons send these little spikes.

Up to the brain, to the olfactory bulbs, and those are located under the frontal lobes. And from there, these signals are passed on to very central regions of the brain. So there's a number of rather small regions located deep in central areas of the brain, and that's also where we experience emotions and memories.

And those are also regions that integrate different signals from different senses. So it comes to no surprise that the sense of smell is very good at blending in with other impressions and also without the bodily internal state. So odors can evoke repulsion, nausea, cause attraction, can stimulate our hunger or thirst.

Those internal states are integrated with the external chemical environment via the olfactory nerve. And that's a really powerful influence that the sense of smell has on us.

CHAKRABARTI: So when you say central regions of the brain, specifically where?

OLAFSSON: So under the cortex, the technical term is the medial temporal lobe.

So basically, in the inner regions of the cerebrum. So you can't see these regions from the outside. You have to lesion some parts to really get to all of these regions. I'm asking because are these regions of the brain that could be considered more primal?

Or that we had earlier in our evolution as a species.

OLAFSSON: Yeah, they're part of what used to be called the limbic system. And that's a term that brain researchers don't use so much anymore. But that's basically it. These olfactory neurons and these olfactory centers are in an older part of the cortex.

CHAKRABARTI: See, the reason why I wanted to get clarity on that is I'm still very taken by this idea that in order to separate ourselves from the animals, Western cultures decided, Western scientists just lost interest in studying smell.

But when you're describing sort of the parts of the brain that are really critical in processing the odors of the environment and how they're much older than our frontal lobe, or our cerebral cortex. It got me thinking that we know that people can live very well and fulfilled lives with no sight, right?

But it's much harder to live if, say, you don't have a sense of touch, taste, or smell. And from what I understand, the rough order, if we can call it, of the evolution of the senses we recognize as humans were touch. Because, what, even single celled organisms needed to know when they interacted with boundaries in their environment.

Then comes taste with a little bit, or quote-unquote taste, because of the adaptation of being able to process chemical signals. Then smell, because then these detecting chemicals in the environment aided in survival, right? You could smell if food was good or bad, or you could smell a potential mate. So these are senses that are core to survival, are they not?

OLAFSSON: Yeah. And if we talk about very simple organisms, there is no point in differentiating smell from taste. That's what we call the chemical impressions on our tongue versus in our nose. But the chemical sensing comes from the same origins. And it's about finding our way to a nutrient source, basically.

And moving away from toxins in the environment. So smelling and tasting blends together when we go very far back. And that's critical for survival. And also in our bodies, the cells communicate the chemicals. So it's like a chemical communication between the cells in our bodies, which consists of billions of different cells.

But it's very fundamental to any kind of biological life.

CHAKRABARTI: Yeah, and it's still, even in the 21st century, smell is still critical for our survival as human beings, right? It's the reason why a scent is added to natural gas, right? Or I was just joking with the staff the other day.

The first thing that someone does when they pull something out of the fridge that they're not sure of, is they ask their partner, can you smell this? And like we're constantly using it. But on the flip side of that, do human beings have a good sense of smell. Because, I don't know, I look around the animal world, just even my dog I was walking this morning. I think, he is processing so much more of the world that is invisible to me because of the acuteness of his nose.

OLAFSSON: Yeah, and so my argument here would be that the dog is not, it's an unfair comparison, because they are really supreme. They're the olfactory kings and queens in the animal kingdom. Because they have a really developed olfactory capacity. But the human species is not too far behind, actually, and when there is a comparison, systematic comparisons made regarding our sensitivities in relation to other animals, in terms of how faint smells can we detect, we perform quite well and even better than most other animals that have been studied, and the example of natural gas is one example.

This molecule that is added to the gas. People can recognize that in the parts per billion range. So you need very small quantities to detect this odor.

CHAKRABARTI: Oh, so interesting. Okay. So then in that case, where would you say that we should focus more on what would we research about smell?

Take me back to when you said one of the challenges is that it's very hard to measure its impact. Is that because its impact is largely subjective, as you said?

OLAFSSON: Yeah, it's both, it's hard to contain a smell and to present it in objective quantities. Which is a sort of, if you want to do experimental research, you need to have a pretty complex machinery.

And sometimes you have to build this machines yourselves. We have developed a smell machine that you can hold in your hand, and that we can use for VR related experiments. So you can walk around and in the virtual environment, you can pick up things and press a button in your hand controller. So that it releases a smell or a mixture of different smells. This took us years to actually build this machine and consumed an entire research grant.

And so these are not things that you can buy off the shelf. So if you want to do innovative smell research, you need a lot of technology. And also, the sense of smell is quite variable. People vary a lot just in their basic acuity, but also which smells they prefer versus which ones they can't stand.

The personal memories are so variable. And I think, but that's part of what makes a sense of smell unique. That we have this very strong, but also very individual experiences with smells. But we have to overcome that challenge and realize not every person is going to be the same. So we're going to have to do research in a different way.

CHAKRABARTI: Yeah. And so how much then of the smell preferences have to do with cultural factors, not just individual ones? Yeah. That's really debated, actually. There is a notion that within each culture, there are some individuals that just like things that other people find weird. So in my culture, it's fermented herring.

I love it.

CHAKRABARTI: I love it too, by the way. (LAUGHS)

OLAFSSON: Oh that's great to hear.

CHAKRABARTI: Go on.

OLAFSSON: I like you already. In other cultures, there are other things like local kind of extreme traditional cuisines that some people like and some other people hate. But that tends to be minority in each culture.

And then there's like a mainstream kind of culture that is more in agreement across different languages, and across different cultures. So the sense of smell varies on an individual-by-individual level. The cultural effects are also there. But I think they are less pronounced than just the differences between individuals, because each person has their own olfactory genetic makeup.

So we have different genes that are turned on and off. And that, according to some estimates, that determine about 30% of why we like or dislike certain things. Just the genetics in our olfactory receptors. And there are, as you said in the beginning, there are 400 different types of receptors, but there are millions of receptors in the nasal cavities. So it's a very powerful system that we have to detect smells.

CHAKRABARTI: I see. But tell me more about this pickled herring. Why did you use that as an example?

OLAFSSON: Yeah, pickled herring is actually distinct from the fermented kind, which is the surströmming. So surströmming is fermented and a pickle, pickled food is pretty, it's a pretty popular cuisine nowadays.

CHAKRABARTI: Ah, forgive me. So I was confusing the two. Okay. I'm a pickled herring fan. So not necessarily fermented one.

OLAFSSON: So the next step then is for you to try the fermented type, which is very strong smelling, and most people have a hard time with it. But you can learn to appreciate it. I'm sure, and I'm a big fan.

It's popular in the north of Sweden where I'm from. But even in the north, there are many people who can't stand it, so it's the individual variation that comes into play here.

CHAKRABARTI: Given that you said there's also some genetic influence, is the passion for fermented herring shared throughout your family?

OLAFSSON: It's a mix, actually. So it's about 50/50. Perhaps I got it on my, those fermented herring genes, I got it on my mother's side. She loves it too, whereas my dad can't stand it, and neither can my sister.

CHAKRABARTI: A little bit later I want to talk, we'll talk in detail about what happens when people lose their sense of smell, because as you mentioned, I think COVID was a time where globally, all of the sudden, the importance of this sense was brought into sharp relief.

But before we get there, on the other end of the spectrum, there's this group of people known as super tasters, right? For example, like my mother. She has always been highly sensitive to smells, even sometimes when I can't even smell them. And to the point where she has a visceral reaction, whether positive or negative, to different smells.

And at the same time, she is a super taster. She can take a bite of something, and as she's eating it, she can discern the individual different ingredients almost. What's different about the physiology of people who have that capacity, versus those of us who have more quotidian abilities for olfactory sense.

OLAFSSON: Yeah. So the difference appears on different levels. I would say. You have this, the number of receptors, the type of receptor that will allow you to detect certain notes in a food source that other people don't detect. That's a kind of a predictor of how you will perceive the food.

But there is also this aspect of emotional reactivity to the food. And that is a more central level. That's something that happens in the brain. But we tend to confuse these two. So people who say that they have a very sensitive nose, they might have a pretty average sensitivity, but they are quite reactive.

So they feel a lot when they smell and taste things. And they attribute that to a sensitive nose, but it is a type of emotional sensitivity that comes into play here. So flavors affect us differently at different levels of processing. And it's not entirely clear just subjectively where our individual disposition is taking us.

But that's why you have to do rigorous scientific testing to see. For example, my first research study was about pregnant women. And a lot of them felt that they had a very sensitive sense of smell during pregnancy.

CHAKRABARTI: Yes.

OLAFSSON: But what we found when we tested them on very faint substances is that they perform just as well as the control group, but they reacted very strongly to the smells when they were there.

So it was not about being able to smell smells that they couldn't smell before, but they reacted completely different. So it was more on a reactivity level, and that is thought to be protective of the child.

CHAKRABARTI: Yes, I went through the exact same thing twice. And in retrospect, it's like it's the beginning of the change, for a pregnant woman, for your entire, the entire rest of your life, you will be constantly thinking about someone else, right? Feeling protective of someone else. And it makes a lot of sense that this primal sense would be a part of that transformation.

Part III

CHAKRABARTI: I actually just want to circle back to something we talked about at the beginning, and that was the time period, the century around which scientists for various reasons demoted smell in the hierarchy of human senses.

Because to me, this also sounds like a particularly Western collective unconscious decision in the scientific community. Because I do think that there's ample evidence that smell has retained its importance as a sense in other cultures. And the reason why I raise this is that just last week I was reading this fantastic article in the New Yorker, it was actually about language.

But in the article, the author quoted two researchers, Asifa Majid, who's in the UK, and Niclas Burenhult, who's another Swedish researcher. And they're actually, they're studying language and cognition. But they did projects with other linguistic groups, one of them is the Jahai.

They're hunter gatherers that live in Malaysia and Thailand. And they compared, they asked English, native English speakers and native Jahai speakers to smell Cinnamon, right? And then describe what that scent is. And it turned out the English speakers had a really hard time describing what cinnamon is, other than saying, It smells like cinnamon.

Or, the quote one person is saying it smells like Big Red, the gum. Whereas the Jahai vocabulary for scent was huge and broad and rich. And so they had no trouble describing in detail what cinnamon smelled. And even more interesting is that groups of the Jahai who took part in this experiment, they converged on their definition of what particular smells were.

So the reason why I ask that is that there are really strong cultural differences in how important or even how respected smell is in a society. And to that, I just wonder what your response is to that.

OLAFSSON: No, I think those studies are really fascinating. And we've learned a lot about non-Western cultures through those, that line of research, which I think is really important.

Part of this is that the ability to have a shared vocabulary for odors, that is more abstract. That's something that we are lacking in most Western languages. We describe smells for things that smell like that, so the big red, for example, smells like cinnamon.

So the more precise we are, the more object oriented we are in our descriptive language, the harder it is to have a shared agreement about what the odors mean, basically. Because you have a very large set of older descriptors, when you only can describe them in terms of what is the visual object that smells like that. So what we are lacking is a type of odor specific vocabulary.

And if we had that in English, for example, it would be, I think that would unlock maybe some possibilities, to have a more olfactory oriented culture in general. So this, I think, our impoverished olfactory language is maybe, it's a victim of the visual culture that we live in to some extent.

CHAKRABARTI: Can we say that again, because of the connection to the deeper parts of the brain to emotion, and as you've brought up many times, that smell has.

Is there any justification to the idea that this impoverished olfactory language may actually also be translating into an impoverished olfactory sense? Could we train ourselves to smell more or smell in greater detail by doing something like changing the language?

OLAFSSON: I think so, because the way it works is that the sense of smell is limited by our ways of making sense of the smells, right?

So part of being a professional wine taster is to have a knowledge base, to have an understanding, to have a rich vocabulary of the different soils, the different grapes, etc. And those are like hooks that you can attach your sensory impressions to. So you can use that to have a more refined perception. And for humans, communication and perception goes hand in hand.

And if you have an impoverished language, it's hard to make meeting of the things that you're smelling. So I think those two definitely go hand in hand. And if you, yeah, if you train people to put words on what they are smelling or tasting. They will be able to pick out subtle nuances that would blend together before.

CHAKRABARTI: So we do need to, as I promised several times in the hour, we do need to talk about what happens when people lose their sense of smell, and the sudden sort of mass experience of that with COVID. Now we didn't get to people who called us with their specific COVID stories. Although I can guarantee you professor, that over many years, especially in the first two years of the pandemic, we heard from so many people who had lost their sense of smell, but nevertheless, here's Claudia Baldwin.

She's in Florida, and here's what she says is important about her sense of smell.

CLAUDIA BALDWIN: I have always had an extremely keen sense of smell, and I think it helps me a lot to discern what to stay away from. And what to be drawn to. One, just one example of what I can smell is I can detect laundry detergent.

There's a certain chemical in all commercial laundry detergents that are not natural free and clear. And I can detect that smell from quite a distance. And if somebody's sick, I am so afraid of catching COVID, because I don't want anything to happen to the sense of smell.

CHAKRABARTI: That's Claudia in Florida.

And here's Jackson. He is in Dedham, Massachusetts, and he also has this very unusual relationship with smell, and here it is.

JACKSON: I was born without a sense of smell. Because of a condition called Kallmann syndrome. It's a pituitary gland issue. And I feel like I'm missing out a lot, on not being able to smell.

But a lot of people tell me I'm lucky, cause there's obviously some bad smells out there, but I'd rather smell something bad than not being able to smell at all.

CHAKRABARTI: Professor Olafsson, first of all, do we know more yet? Maybe the answer is no, but about why COVID knocked out, temporarily, a sense of smell in so many people?

OLAFSSON: Yeah, there has been a lot of research on that. And several cell types in the olfactory mucosa have these cell types express a gene where the coronavirus can attach — and so enter the body through those cell types.

And that created a sort of disarray in the olfactory mucosa and olfactory epithelium, which disrupted the process of generating new nerve cells, basically, they are constantly replaced. And if there is obstructions in this very delicate process, then these new nerve cells cannot be fully developed, and they can't find their way into the brain. So there is some progress there. We know the mechanisms of how that worked quite well.

One thing that is harder to explain is when people have distorted smells. We heard a lot about a certain COVID smell. So things that shouldn't smell bad that started to smell bad, for example, fried food or toast, toasted bread. They tended to smell like a type of sewage smell that wasn't there before.

So these things are qualitative distortions. Those are still not very well understood, but it happens. As the olfactory system tries to recover from this insult of the virus, then some things get misconnected in some way. And that's when we get these qualitative distortions. But the exact processes of that, we still don't know very much.

It's a sign that the olfactory system is trying to heal. So in some cases, it can be a positive sign that you're about to regain your sense of smell. But for some people get stuck in this intermediate state where things don't smell like they should. And that can be a horrible experience. I remember people telling us that when they lost their sense of smell due to COVID, that first of all, there was the shock of it, right?

Because it's just like suddenly not being able to see or listening to music and then not being able to hear it anymore, right? It was that. But then in addition to that, in addition to feeling cut off from this entire way of sensing the world, I remember we had some callers telling us that they were almost like in a sense of, there was a profound sadness that came along with it, because of its tie to memory.

That even just like walking into a kitchen and knowing that someone was cooking your favorite meal or like a mother's recipe, but not being able to smell it, it almost made them feel detached from a core part of the memories and experiences that defined who they were as human beings.

OLAFSSON: Yeah, that was one of the most, to me, the most revelatory findings when people started to interview those who had smell loss. It's one thing to say that you feel sad and depressed, and that was very common. But just the way that smells can really enhance your quality of life. You feel like you're part of the world.

You have emotional, your emotional wellbeing and your sense of being in the world. That's something that was lost in so many people. And to say that you should be lucky that you don't smell all the nasty smells out there. That's one of the reasons why it's so hard to lose your sense of smell, because you're not really taken seriously.

People don't really understand it until they experience it themselves. And I think what I want to do is to also communicate that side of the story, all the patients that contacted me during the pandemic, just telling me about these types of, the sense of loss that they experienced, that was really profound to me.

CHAKRABARTI: In every loss, there's a potential gain. Because the flip side of this is that can we learn ways to become even more connected to the world, become even more cognizant of the smells around us, make life better by being able to use this ignored sense.

OLAFSSON: Yeah. Of course.

If the sense of smell is completely lost, there's unfortunately no real perfect treatment so far, but there's a lot of research done on how to recover your sense of smell. I read a paper that was published just earlier this week about a medical treatment that gave promising results.

So I'm sure that in the next few years there will be more medical therapies to help people recover the sense of smell. But for those of us who do have a functioning sense of smell, becoming more aware of nuances in cooking and wine and food and drinks, cultivation and appreciation. Those are things that I think anyone can get better in that sense.

Learning more about where the food comes from, taking a wine tasting course, maybe becoming interested in perfume, starting to read more about different food ingredients and spices, and paying more attention to those subtleties of smelling and tasting. I think that there's a myriad of ways.

And even for those who have smell loss or smell distortions, there are cookbooks, especially developed for those people nowadays, that you can find online. So I think that's really, it's not just for those who already have a strong sense of smell to begin with. So anyone can really, most people can cultivate their appreciations of smells and taste.

CHAKRABARTI: You know what I find so ironic? That on the one hand, you've talked about the impoverishment of research over the past couple of centuries in terms of how our sense of smell really works. But on the other hand, especially in the mid 20th century to now, billions of dollars have been invested in using our sense of smell to shape behavior.

It's the reason why, to put it crudely, that stores pipe in certain scents into the stores. To evoke certain emotions in you that might make you want to buy that perfume or buy that cookie from the store that you're walking past. Everything to that too, like the entire food industry, it spends so much money in trying to get things to smell a certain way so that you will buy it, even if there's not actually any nutritive content to what's in the package.

So it just makes me think, are we now, perhaps due to COVID, at a turning point. Has there been more interest in your research or that of your colleagues?

OLAFSSON: Yeah, for sure. It has been an increased interest in this research, and it's been driven by the effects of COVID, but I think that people are starting to recognize also that these industries are, they are huge, multi-billion-dollar industries.

And there is a lot of research being done, and perhaps it hasn't really reached the public. A lot of it is done in the private sector and not so much by universities. And we are more keen on getting our research out there to the public. That's part of our job. With the experiences of COVID in fresh memory, hopefully there will be more investment and also more interest in the human sense of smell. That's what I'm hoping for.