The Happiness Lab with Dr. Laurie Santos - The Sweet Smell of Happiness

Episode Date: February 5, 2024

Does happiness have a scent? Dr Laurie has been trying to remove the bad smells in her life and bring in more fragrances that enhance her wellbeing. But she's noticed that some of the smells that bring her joy can be a little weird - like musty books and rotting seaweed.  So what's going on in our noses and brains? Laurie turned to neuroscientist Dr Rachel Herz (author of The Scent of Desire) to explain why we respond to certain smells and how we can use scent to reduce stress, boost our happiness, make us perform better and even to find the perfect mate.  See omnystudio.com/listener for privacy information.

Pushkin. know and like, and that means I'm often checking out new products before advertising them to you on the Happiness Lab. I often come home to random packages waiting for me on my doorstep. Our ads are what keeps the show going, which means you can keep listening to the Happiness Lab for free. But the other reason I love our advertisers is that the people who work at the companies who sponsor us are usually fans of the Happiness Lab just like you. That's why they want to support the show and all the work we do. Take, for example, my most recent delivery, a colorful box of soaps and cleaners which had a handwritten note inside. We are so excited to work with you. We are big fans, it said. Please enjoy some of our favorite products. Thanks, Mrs. Myers. These scented samples arrived at the absolute perfect time because over the past few months, I've been on a bit

of an olfactory journey. It's a challenge I started after I chatted with the great happiness expert, Gretchen Rubin. For some people, I think that this can be kind of an overlooked sense. Last year, I spoke to Gretchen about her new book, Life in Five Senses,

which explores how we can get more joy from paying attention to the sights and sounds around us, but also to the smells. Gretchen says we often neglect the impact that odor can have on us. She told me I should try harder to curate the smells that surround me. There's both eliminating the negative, which is what are the things that are bringing you down or draining you, and then the adding, which is what are the things that will make it feel richer. So you could say like, okay, I'm in my home office, like maybe there's

something that smells bad that I need to get rid of. Or you can add something good, whether that's making sure that you open the windows so that you get fresh air and the smell of the outdoors or a plant or a scented candle. Who am I to argue with Gretchen Rubin? And so I've been working hard to eliminate smells I don't like and to introduce new scents that I do. But the process of paying attention to the scents I like has been kind of strange. I found lots of objectively nice-smelling soaps and lotions that I totally dig. But I've also noticed other smells that aren't exactly nice, but that I do find comforting and relaxing. Like the musty smell of old books or the scent of my favorite beach at low tide.

What was behind my preference for these kind of weird smells? I really wanted to better understand this complicated intersection between smell and happiness a bit better. So I reached out to someone who also has a thing for odd odors. I know you're talking about the scent of skunk. My dirty secret pleasure. This is smell expert Rachel Herz. Which actually, since I've come out of the closet, many people come and confess to me that they also really like the smell of skunk, so I am not alone.

Rachel's a neuroscientist who's been studying our sense of smell for over 30 years. She's written books like The Scent of Desire about why smell is so enigmatic. And That's Disgusting, a book exploring all things that turn our stomachs. For most people, the stench of a skunk definitely falls into that second category. It's pretty awful. But Rachel's research has shown that our relationship with smell is so personal that even a scent evolved to drive us away can be oddly attractive. And for Rachel, the smell of a skunk only has positive associations. I do like the scent of skunk. And the reason for it is because the first time I ever smelled skunk,

I was in the backseat of the car. I was probably maybe around four years old. It's hard to say exactly. Middle of the summer, windows roll down, driving through the countryside, beautiful day. And all of a sudden, there's a scent wafting into the car. And from the front seat, my mom says, oh, I love that smell. She doesn't actually name it. She just says, I love that smell. So here I am, beautiful, happy. I love mommy. Mommy said something positive. So whatever that smell is, you know, I love that smell too. So fast forward about three or four years and I'm

on the playground and all of a sudden that same smell comes along and I go, oh, I love that smell. And people go, ew, gross, you're so weird. That's disgusting. That's skunk. And I did not know that that was a skunk, first of all, and B, that everyone thought like Pepe Le Pew, whether they really believe it's horrible or not. There's all this negative connotation around it. I was already perceived of as weird because I was a newcomer to the school. So this really sealed my fate as someone who should be stayed away from. And this really also explains how our responses to all odors are actually based upon the meaning that we have learned to be associated with the odor. Most times through personal experience could also be cultural. So for example, it could be the

case that I had never smelled skunk before, but just seen the Pepe Le Pew cartoons, in which case I would have formed a negative association to that skunk smells bad, it's supposed to be bad, even without having ever smelled it. So we have this sort of interaction between our personal experience, the cultural significance of a scent. And one of the other things that's interesting too, is that skunks are actually not native to Scandinavia. And so they're not known there. And I had some friends from Sweden visiting me, actually olfaction experts as well. And we were walking down the street near my house when I live kind of in a country-ish area and it was in the summertime. And it just so happened, luckily enough for me, that that scent was, you know, on the, on the breeze. So I turned to my colleagues and I said, have you ever smelled that before?

And they go, no. And I said, so what do you think of it? They go, it's okay. It's no, it's interesting. It's like, well, what is that? So I said, that's skunk. And then they were like, oh yeah, yeah. What is that supposed to mean? And then I said, everybody here thinks it's awful, or they're supposed to think it's awful. And they're like, oh, you know, it doesn't have any good or bad necessarily to me, you know, could be nice. And our responses to smells are based on the meaning of the smell, but they're also based on how strong the scent is to us. So I have never been sprayed by a skunk. I've never had my dog sprayed by a skunk. So I have to like live up close and personal with that scent. And my encounters have been, like I mentioned, on the the breeze just sort of at some kind of a distance but this also speaks

to the fact that my intensity perception of skunk is unique to me to a certain extent so other people may at the same intensity of just on the breeze be perceiving certain chemicals in that bouquet is really intense even though other people might consider it kind of moderate or weak. And if you think something smells really intense, it's going to be more negative. So there's also the genetics behind our olfactory receptor expression, and everybody's actually ever so slightly different from everyone else. That is going to play into how strong something is and the more strong something is. Anything, even like your favorite smell, if it's like super, super pungent, you're going to be like, oh, that's too much like perfume, for instance. And so I'm curious, given that negative experience on the playground, did that make

you kind of anti-smell? Did you like never want to think about that sensation? Because you seem like somebody, at least as an adult, who's kind of into smell. Oh, yes, absolutely. Very, very into smell. And I actually always was like, I always was a really sensory person. Like my mother was always yelling at me, stop squeezing the bread. I was always definitely smelling everything around me, but I actually thought that was normal. But in some ways being really into smell is really not normal. In your book, you talk about how smell is this orphaned cousin of the senses. What do you mean there? Well, I think that there's a disconnect between being experientially or perceptually into smell. So there's definitely a lot of people

that will only buy certain products because of how they smell. Like they're unscrewing the cap of the shampoo in the drugstore to make sure that they like it or other kinds of products like that that are definitely making a lot of simple life choices based on how something smells to them and actually maybe even not so simple,

maybe like your partner or other kinds of things like that. So I think people's actual experience with scent is much more deep and broad, but the discussion around scent and the verbalization and the recognition that this isn't just something trivial or just a little accessory to my existence, but actually something really fundamental to my existence, that's where the disconnect is. And that's where most people, as well as most scientists for a long time, have really considered the sense of smell to be so marginal. And to really speak to how much we disregard scent, a couple of years ago, actually sort of in the height of the pandemic, we collected the data in the spring of 2021, developed a survey to look at, first of all, how people value their sense of

smell to hearing and vision. And then also in comparison to some basic commodities like your cell phone or a dream vacation or your hair, for instance, we had different kinds of things, physical and then more sort of social and so on. And we found we had a large data set of subjects who were both a university level and also sort of real adults in the 40 something group. And amongst the college students, 25% of them would give up their sense of smell to keep their cell phone. And 50% of them would give up their sense of smell to keep their hair. The adults group was a little bit less, you know, throw it away, but they were pretty close. Like there wasn't one, like they were like, oh, we wouldn't do this at all. They were like maybe

a few points less willing to give up their sense of smell for something else. But I was really quite stunned. And also because of the fact that although we didn't really have a good comparison point, like to do this in 2018 and see the comparison. But I thought because there was so much media about smell loss and about how people's stories about how awful it was, their even temporary smell loss and then long term smell loss, that there would be this sort of recognition like this should be a high point of people saying, oh, my sense of smell is actually more important than I thought it was. And this kind of fits with what we see just in the world. I mean, when we think

of technologies, right, like I'm wearing contact lenses right now that improve my vision. We have hearing aids to improve people's hearing. We don't actually have any technologies that help us improve our smell, but that might be part and parcel of the fact that we just like don't see smell as that important. Well, sort of two sides of that. One, you're absolutely right. And up until now, and I hope that this is going to be changing soon, but the American Medical Association, for example,

values smell loss is only between one and 5% of your life's worth value. So for example, if you were in a compensation case, like you become blind or you lose another sense, how much should you be compensated for that? Well, vision, you get 85% of whatever your salary might be extended out for the next 20 years. For smell, you get anywhere between 1% and 5%. So really sort of idealized as hardly important at all. However, as a function of the pandemic and also new technology, new innovation. There's actually various things in the pipeline that are going to be available relatively soon, I hope, that will

in fact be things that can help people's sense of smell be augmented. So sort of the equivalent of a hearing aid for your nose. And that's going to be really important because what I learned from your book is that it really deeply affects us and our happiness when we lose a sense of smell. Give me a sense of what are the kinds of things that happen when we lose our olfaction. So what is really shocking to people, and unfortunately, unless you've had the experience, you really just don't realize it. Most people will say, oh yeah, well, food, I can see how that's involved. Or maybe I couldn't smell the gas leak. So there's certain danger things that, okay, I could understand that sort of more readily, but actually our sense of smell is involved in pretty much everything about our life in every way, every day. So food, of course,

because what most people don't realize is that the sense of taste is really only salt, sour, sweet, bitter, and umami, but everything else we experience when we're eating. So bacon, for example, just tastes like salt. The flavor is comprised of 150 different volatile organic compounds that fuse together to make this bouquet of bacon. And people use the word taste, they really should be saying flavor, but all of that is to do with your nose. Food really does lose pretty much almost all of its hedonic pleasure qualities other than salt, sugar, and fat. And people get very upset. And depending upon their personality, their previous relationship with food, it can become more and more serious. There's also all the aspects of one's personal life, which we don't realize. I mean, our intimate

relationships with other people, we don't quite necessarily grasp that you hug somebody, even if just like in a certain proximity, maybe they have a certain perfume or cologne they usually wear. When you smell that, that's like kind of bringing you intensely together with that person. Your memories are based very much on things that you smell. People don't often realize that they've smelled something and it's making them feel nostalgic or it's bringing them back to a specific moment in time. And all these things as it's going along are actually triggering emotion. And this is because the area of the brain where our conscious perception of scent takes place is the same part of the brain where emotion memory association is being formed. So the same brain area is doing these two things. So instantly that we smell

something, we are getting some kind of feeling, some kind of visceral connection to that. And it can be negative. I mean, for example, PTSD can be triggered by scent. And often those episodes are amongst the worst because it's so viscerally overwhelming because of the emotional intensity of it. But likewise, we can also get so much joy and direct connection to other people, to our past, to places through our sense of smell. So that's one big misconception about smell, this idea that we think it's like not that important, but in fact, it matters for so many different aspects of our lives. I think the second misconception that we have about smell involves where our different smell associations come from.

I think we assume that certain kinds of smells are kind of built in as bad. Certain kinds of smells are built in as good. Is this really true or is this another spot where we get olfaction wrong? Pretty much there is no innate response to a scent per se. And what I want to do is sort of unpack a little bit of what is going on when we're smelling itself. So when we're smelling, we're perceiving volatile chemicals. So that means chemicals that are floating through the air. We inhale, those chemicals come in through our nostrils. They then interact with the olfactory sensory neuron, which is basically at the level of our eyebrow. But when we are smelling something, these chemicals can have

a variety of different effects on another system as well, which is called the trigeminal system. It's actually a tactile system where, for instance, if you're chopping onions, it makes your eyes tear. If you're smelling mint, that cooling sensation comes from trigeminal. The hotness of a hot pepper comes from trigeminal stimulation as well. So many smells also trigger the trigeminal system. If at the same time as smelling something and the trigeminal system is activated very intensely, that can feel painful.

That's pretty much the only quote unquote innate response we can have to a smell. If it's activating the trigeminal system as well as the olfactory system and it's hurting, then it's going to be like immediately no. Other than that, we are pretty much a blank slate. Now it's kind of hard to imagine that because it seems as if skunk is bad and rose is good and everything else. But really places to look for this are number one, newborns. Although there's a little caveat there as well, because actually by three months of gestation time, the fetus is already capable of detecting the chemicals in amniotic fluid that its mother

is consuming. So we're already learning. And where this really plays into a major impact is where, you know, food preferences come from. So you can have a baby that's born ready to eat the food of that culture because of the fact that it's actually been already pre-exposed to that food before it was born. But the idea that, you know, there's this sort of universal good, bad, and otherwise is really based on experience because newborns, if they're given, for instance, vanilla versus something that smells like sweaty socks or vomit,

if you look at their facial expressions, which is how you're going to judge if they're liking it or not, you see everything from grinning at smelly socks and vomit or making a disgust looking face to vanilla. And then you look cross-culturally and you also see huge variation in what is considered good or bad. And we really see this in the food. So like the idea of one man's meat is another man's poison that really comes from this massive effect of culture. One of the examples I loved from this massive effect of culture. One of the examples I loved was this interesting smell of wintergreen and looking at how it's perceived between Americans versus the British. Do you want to share that story? Because I found it so compelling. It's almost funny in a weird way, because especially if you're an American and you're listening to this, you're like, well, of course, wintergreen smells good. It's like,

it's a mint, it's a candy, it's paired with sugar, you know, who doesn't like wintergreen? But it turns out that in the UK, sort of like, you know, if you think of us, the United Kingdom, the US, two countries separated by a common language, what else is different between the two of us? Well, people in the UK generally can't stand the smell of wintergreen because their experience of it comes from the scent of this analgesic balm, so medicine. And then nowadays, actually, wintergreen is also the scent of toilet cleaning products in the UK. So A, medicine, B, toilets. I don't think so. Not eating that anyway.

Versus the US where it's candy and gum. So really different association, positive in one case, negative in the other. So this explains why my friends from England often turn their noses up at perfectly good American candy. But could a Brit learn to love wintergreen in the same way I do? Well, it turns out that we can train ourselves to love smells if we can link them to positive experiences. And we can even use these newly linked up scents to lift our spirits when we're feeling down. We'll hear more on all of that after a quick break and some of those all-important ads. Neuroscientist Rachel Herz had to put up with lots of teasing when her schoolmates heard that she liked the smell of skunks,

those animals that reminded her of happy summer car rides with her mom. that she liked the smell of skunks, those animals that reminded her of happy summer car rides with her mom. The power of smell to take us right back to happy as well as sad moments from the past is almost unparalleled. A whiff of cologne can remind us of a long-dead romance, while the smell of a Sharpie

can transport us back to college exam time. While there are some scents we'd happily never smell again, Rachel suggests we try to identify the smells that prompt a positive reaction, ones we can turn to whenever we need a little happiness boost. Her go-to fragrance is from a childhood shampoo. We moved around a lot when I was a kid. My parents were professors. We lived in Europe. We lived in the U.S. We were bouncing around pretty much every 10 months, sometimes every six months for the first six or seven years of my life. So at the age of seven, we land in Montreal. And it was tough with all that sort of moving around,

especially when I first started school. I come in as the newcomer. I don't even last necessarily the full year. I'm yanked out. I go somewhere else. So like I shared with the story of the skunk, you know, I'm a newcomer and I'm weird already. And now I'm proclaiming that, you know, skunk is one of my favorite smells. So definitely ostracized, did not have friends, felt really alone, felt really isolated, really desperately wanted social connection and so forth. And I was pretty unhappy. And, you know, there was all kinds of things going on that very first year in Montreal. It was a terrible winter too. It was like they had like crazy amounts of snowfall and really, really cold.

So that really also impacted even just going outside to play and so forth. And one day during these cold days, someone came like literally a traveling salesman or door-to-door salesman with these packages of shampoo and conditioner. And I think also maybe like the bubbly stuff to put in a bath. And he came to the door and I remember I was at the door. My mom and I think also maybe like the bubbly stuff to put in a bath. And he came to the door and I remember I was at the door, my mom and I both answered the door and he had these bottles and he, you know, do you want to buy them? My mom's probably like pretty much definitely no off the bat. And I'm like, wait a second, wait a second. Can we smell them? Because no, why not? I like to smell. And I think I could even already smell it before unscrewing it because it has a really intense scent. And I was just unbelievably drawn to this smell and absolutely adored it.

It was like happiness magic in a bottle. And I'm like, please, please, please, can you buy this? So she did and kept it in her bathroom, my parents' bathroom, so that I wasn't using it all the time. And I think this also made a difference that it was kind of like special occasion use like bubble bath or shampoo. And throughout that first year or two, when I would feel really unhappy,

I would actually just go and smell it. And it would just immediately give me this feeling of calm and just the pleasure in and of itself of smelling it was just phenomenal. And I would say that that smell was unique to me at the time, but it isn't like the smell from Mars. I mean, it is a scent that you will find in other products. It actually has a very piney aroma to it, which obviously I probably was familiar with, with some other things, but just this particular mixture kind of captured a sort of a sweetness

and other associations that somehow just were like sublime to me. So it emptied out who knows when, how many decades ago, gone. I'm never going to smell it again. It's a great sadness that I'm never going to be able to smell this. I did remember a couple of things about the bottle. One was that there was a horseshoe on it. And the other was that it was this deep kind of eucline blue. That was another aspect to the color was really intense. And I thought that it was something like algemarine or something along those lines.

You know, this was post the book you're talking about. So I talked and actually when writing that book afterwards, people would contact me and say, I think maybe you mean this. And none of them were right. Like they'd try to be helpful. Like I, maybe it's this shampoo that you were thinking over this bubble bath. I'm like, no, no, that's not it. Anyway, fast forward to maybe now, maybe like eight or nine years ago, I'm not exactly sure what, but I was doing a documentary and I was being interviewed in a hotel room near Harvard square. And I told this story and like this long lost love of this scent that's gone. And then afterwards that we were going to do, and they were going to be shooting some B-roll and doing some other stuff, was to go to this

kind of old fashioned drugstore that has a little bit of everything. You know, it has old shampoos, it has perfumes, it has a floor to ceiling, all kinds of stuff. And I'm in this drugstore walking around, you know, smelling things, looking at things. And all of a sudden, I come to this one little spot on the shelf and I see this bottle that's that Eucline blue and it has the horseshoe on it. And I just like, oh my God, is this it? Is this it? I pull it out. The person who owns the store is like, what are you doing? I'm opening up the package to sniff it. And it was it. Unsurprisingly, I bought, you know, four bottles, the whole amount that was there. So, and I don't even use it. I just go and I sniff it from time to time. So I think at the time I misremembered it being called aquamarine, but it's actually

algemarine. Here's the bottle. I'm going to open it up. I'm going to give myself a little boost of happiness. So it's just this phenomenal. I'm so, I so love this smell. It's, it's one of the things with smell is actually really hard to verbalize and describe. So even me, and even though you think I would have had a good way of describing the smell after loving it for so long, it's very difficult to describe. Maybe actually that's one of the reasons why I love the smell so much because it's a, it's an odd combination. It definitely has sort of like a blue spruce note. It has what in the fragrance world is called marine sort of watery notes to it it's kind of sweet maybe it even has like some cinnamon kind of like a spicy quality to it but it's just this perfect blend of all of that to me i mean you might smell it it could smell different to you

so this is also we're all unique we not only do we have a unique body odor we all have a unique nose so it smells ever so slightly different to everyone. But for me, this is the sort of spicy, sprucey, vanilla-y, kind of wonderfully blue bottle of Aljamarine. This is kind of the beauty of smell is that it seems to get attached to particular contexts, but not just kind of any context. It seems to really get attached to emotional contexts. So talk about biologically why smell does that so well. Really the physiology, neuroanatomy of the sense of smell is emotion. And so from a, even a neuroevolutionary perspective, the part of the brain that is now subdivided into the different structures of the limbic system where we have the amygdala, which is actually, you know, very central to the processing of smell as well as the hippocampus and other

areas, that whole structure was not subdivided. And in fact, just for detecting chemicals and smells are chemicals. So literally our ability to perceive emotion, I like to amuse, came from our ability to detect chemicals, to smell. And if you think about it, the function of the sense of smell and the function of emotion is very much the same. It's about what do I like? What gives me joy? What am I gonna go towards? And what is bad for me?

What do I wanna stay away from? And essentially these mechanisms of survival. But as I mentioned before, the part of the brain where we are experiencing conscious perception of that's lemon, that's skunk, that's caramel and so on is the amygdala hippocampal complex of the limbic system. So the part of the brain that's actually processing emotion, associations, and memory is doing two jobs. It's doing that and it is processing smell. So the primary olfactory cortex, like we talked about the primary visual cortex, primary auditory cortex, and so forth. The primary olfactory cortex is the amygdala hippocampal complex.

And is that one of the reasons why smell can seem so fast? I feel like sometimes I'm like, say, walking down the street and I'll have this moment where I'm thinking of like the joy of Christmas. I get all these wonderful feelings. And then I realized like, oh, I'm smelling pine or I'm walking by and I start thinking of my mom and I'm like, oh, that's lilacs, which is one of her favorite flowers. Like, is that why the emotion seems to come so fast when we're experiencing these smell memories? So I would argue, and this is sort of a statement that's very hard to test, but I believe that smell elicits emotion first. And then we figure out, oh, it's Christmas. Oh, it's my mother's perfume. Oh, it's when I was at my aunt's house and I had this. The emotional aspect is first and foremost because the brain

is being activated emotionally when we smell. The two things aren't necessarily happening at once because it's the same part of the brain. So you can't experience smell basically without emotion. The emotion could be pretty bland. It could be pretty like, you know, ho-hum. Or if the scent is really unfamiliar to you, it could even be like kind of cautious. I don't know what this is. So, you know, I have to learn kind of the meaning of it and so forth. But it is impossible to sort of have a conscious perception of scent without some emotionality involved because it's the same brain area that is doing both things. Sometimes we, or maybe even a lot of the time, we have experiences with scents sort of fleetingly that are kind of altering our mood and we're not exactly sure what they are,

but what typically happens is we discount them. I mean, one of the things that's sort of unfortunate about the sense of smell, and I think one of the reasons why it's so ignored is because smells are invisible. And we are so visually oriented as a species that we're always like, what is that? Where's that, you know, point to this point to that and so forth, you know, for the data in a sense of our experience that when something isn't visible, or even when we don't know specifically what the source is. So for instance, you could hear something, you'll know where it is, you probably think most likely what it is, but smell can be such a black box in that way, that if we don't know what something is, we often say we don't even smell it. So people can actually

be presented with a smell that's, you know, high intensity. They've never smelled it before. And I say, so can you smell something? People will say no, just because they don't know what it is. But that kind of means that what that means that emotion is getting in kind of under the hood, right? That these, the emotions that might be associated with smells can be really powerfully affecting us, even though we don't even realize what the smell is. So what I would say to that, that particular comment

is if we don't know what the smell is, then it doesn't have a prior association emotionally to us. And if anything, it's going to elicit a little bit of a cautious, like, what is that? Let me take a step back.

So better to play ignorant and go, oh, no, nothing to smell here, rather than sort of have a commitment to it in some way or other. However, if it is a scent that we have prior experience with, even if it doesn't come to mind immediately what that is. So you could, for instance, be walking down the street and smell some kind of floral scent, not be able to pinpoint it, not be able to name it. And it suddenly makes you feel good because it just so happens it is your mother's favorite flower, but you wouldn't necessarily have realized that, but you still have that emotional connection. So it does get under the hood that way. The other thing that you've shown in some of your experimental work

is that this kind of association can go the other way. You've really looked at the domains in which we build up these associations, even in kind of strange contexts, like for example, playing good or bad video games. Tell me a little bit about this study. Yes. Well, so we can engineer our own scent associations however we want to do that. We can actually do it in a very positive way to sort of set up our own scent apothecary. Like I can get fragrances that I don't really know, so I don't have past association and get myself into specific mindful, positive mood states with different ones of them and create those positive connections. So that then when I go back to that particular smell, it can get me like focused and relaxed or

excited and invigorated or whatever the case might be. But what we did in my lab was actually set up a sense of failure and frustration. And what we did is we got a perfumer to make a fragrance. So it was actually not unpleasant. It was sort of like in the sort of neutral rating range, but it was unfamiliar. And that was key because if a smell is already connected to something that you have an association to, it's very hard to reconnect it to something else. So whatever that first association is, is the one that sticks unless the subsequent one is really powerful emotionally. And this is why most of the time when we smell something, it tends to remind us more from earlier points of time in our life because that's the first time we probably encountered it. So like the first time you encounter whatever it is, it's going to be what sticks.

But we experienced so much in childhood. That tends to be why we're taken back to childhood so often. childhood, that tends to be why we're taken back to childhood so often. But what we did is we took this unusual chemical bouquet and we had people play a really frustrating computer game that was rigged to make them lose money. Now, it wasn't their money in the first place. We gave them $2.50. These were Brown students, so they're highly motivated. They want to get A plus on everything. So we said, depending upon how good you are, it had nothing to do with skill, but how good you are, you can double your money in five minutes by playing this game. So he said, depending upon how good you are, it had nothing to do with skill, but how good you are, you can double your money in five minutes

by playing this game. Like, and you know, $5 against a trivial amount, losing $2.50, however, believe it or not, is really traumatizing. But also because the computer would make these noises like, eh, you know, you got it wrong. And it got them into a really negative mood state. So it's really easy, as I'm sure you well know

from your research, to get people upset. Not very easy to get them beyond kind of a baseline level of average happiness, but to get them upset, it's really easy. And with highly motivated college students, probably the easiest of all, especially if you're telling them they're failing at something.

So after this association that we set up with this unfamiliar scent, we then had them do another series of tasks with that scent in the room or a different scent that was equally unfamiliar. So the perfumer came up with a couple of different fragrances or people were assigned these other tasks in a room that was unscented. And what we found on these series of subsequent tasks, when that scent that was associated to frustration was also there. They did much worse on things that required persistence. So I'm going to stay with this and try harder. Basically performance, which is interestingly not the same as skill. So I can have an innate ability, which is not being reflected by my performance. My performance to be good has to be also motivated.

Like I have to want to succeed and achieve. So I can have the ability to do the test, but I don't want to do the test. And basically we saw that disconnect. We saw ability being maintained, but performance really modulating as a function of whether the scent was the one that was connected to failure or not. So incredible.

But this is not the only domain in which smell can affect us. No discussion of emotion and smell would be complete without talking about smell and sex. As a person who doesn't know that much about olfaction, I really have the strong sense that smell matters a lot for attraction. What does the science actually tell us?

So yes, smell does matter a lot for attraction. It matters a lot for intimacy in general because as I mentioned before, like if you go and you hug someone, you automatically get some of their smell like it's a very proximal intimate sense so you can smell them whether it's the body lotion shampoo cologne natural body odor maybe a combination of all of the above and that gives you this sort of depth into that person. But above and beyond that, it's actually extremely important in the attraction that women in particular have towards an opposite sex partner. And this is,

in fact, based on evolutionary theory. So there is also evidence that for homosexual relationships, smell is also important, but it doesn't quite have the same navigation in terms of why and what we find specifically attractive in our romantic partner as it does in this sort of picture for heterosexuality, which is based on having children, sort of propagation and based on the idea that we're all here just to replicate and get our genes out into future generations. And as a function of that, there's a different strategy that males and females would engage in for doing that most successfully.

And so for females, the cost is very, very high. You know, first of all, nine months of pregnancy where not only are you much more vulnerable during those periods, that period of time, you need more energy. You can't move around to the same extent. So you're in a definitely vulnerable state from your own self-interest of survival. Then after the infant is born, you have at least one year where if you were to get pregnant, you would stop lactating, so not be able to breastfeed. And this is, you know, again, kind of based on our evolutionary history. This is not based on having formula or anything else. But if you are not lactating and your infant is not able to eat solid food, then that infant can die.

So you have basically two years where you're out of commission for all this energy and cost being spent on this one child who hopefully will survive and thrive and then have children herself and then go on and perpetuate your genes into subsequent generations. But the other piece of this story is that that child be healthy. And what determines your health? Well, your immune system determines your health. And it turns out that the blueprint for your immune system,

the genes for your immune system is externally represented by your body odor. Everybody actually has a unique particular code for their immune system. And everyone has a unique body odor. It's as unique as your fingerprint. This is how the tracking dog finds you when you leave your t-shirt behind in the jail cell and doesn't just go after any old random person because nobody actually smells identical to you,

except if you had an identical twin eating the exact same food as you. But taking that particular qualification aside, you have your unique scent and that unique scent is actually a representation of the genes of your immune system. Now, from a strategy perspective, the best strategy for a female is to mate with someone whose immune system is going to be complementary to her own, not going to double up on any nasty, bad recessive traits and cover things that she doesn't have coverage for. So if I have coverage for diseases A through M, I want to be with someone who has N through Z. And that will ensure that the children I have with that person are going to be maximally healthy.

So that actually seems to be part of what is going on with attraction to somebody's natural body odor. But it really turns out that it's not the case that we have this little biological switch in our brain or nose going, you smell like you're genetically different in a good way, you know, let's have a baby, but rather that you don't smell like family. And it's basically like a scent incest avoidance cue

because from the point of view of smelling like family, why that's a problem, we know that when people are too genetically related, then there are problems. First of all, there's even problems getting pregnant. Then if you do have a baby, there's a greater likelihood for recessive traits to be manifested, which can lead to terrible diseases that don't allow for thriving, surviving, and having children yourself. I think there's two really cool things about that. One is that we have this learning mechanism that's so powerful that we're like detecting the smell of different immune genes by detecting whether or not somebody smells like our family member and avoiding people if they smell like

that. But the other cool thing is that that suggests that we're all doing it differently. Like there's not one like awesome smelling guy out there that every single one of us thinks is like really olfactorily hot. Yeah, absolutely. It's kind of different for everybody, which is cool. Yes. So as a female looking for my ideal scent match male in terms of this whole being heterosexual reproduction, there's no Brad Pitt of smells. There's going to be a different Brad Pitt for every woman. So the idea that we're basically all have a different sort of beauty metric or sexiness metric for who the best match will be is based on the individuality of our own genetic makeup. The smell of family, though, can still be positive, but not in a sexual way.

So the smell of family can be like really comforting, really cozy. I want a hug from this person, but that's different from I want to have sex with this person. So there's this difference between wanting someone sexually versus wanting someone emotionally. Although the two can also become the same when we're in an intimate long-term relationship with someone. In case you were wondering, I googled Brad Pitt. And at least according to actress Jennifer Lawrence, he smells like sandalwood, which may or may not be your thing. After the break, we'll look more at scent and memory, and what you can do if disaster strikes and your sense of smell starts to fade. The Happiness Lab will be right back.

No sooner had the warm liquid mixed with the crumbs touched my palate than a shudder ran through me and I stopped, intent upon the extraordinary thing that was happening to me. This is one of the most famous lines in Marcel Proust's In Search for Lost Time. The story's narrator has just dipped a madeleine cake into a cup of tea and taken a bite. The scent of that magical cup of tea and taken a bite. The scent of that magical combination of tea and cake sends Proust's character right back to his fondest childhood memories. An exquisite pleasure had invaded my senses, the narrator says, and at once the vicissitudes of life had become indifferent to me. Its disasters innocuous, its brevity illusory.

This is perhaps the greatest ever description of how our senses can briefly transport us to a whole other plane of joyful existence. It's a passage that always intrigued Rachel Herz, even prompting the neuroscientist to carry out her own research on how smell and memory mix. So there's a couple of things that are going on in Proust's description of his Madeleine Biscuit and Linden Tea that I think are really profound and really speak to the experience of what happens when a scent evokes a memory. One of the things that's really brought out by his description is that the experience of emotion comes first. He's writing about how he feels when he takes this flavor concoction in before he ever gets to,

and like literally pages before he gets to, my aunt's house in Cambrai, this is what was happening and so forth. So the primacy, the sort of phenomenological aspect of emotion first, and then cognition after, is really fleshed out in the way that he narrates that experience. But a couple of other things connected to that, which I think are very important and interesting. So we have certain things that will remind us of particular past moments in our life, autobiographical memories. Now, in research that I've done, and other people have subsequently replicated it and so forth, I found that when we have a memory that's triggered by a scent, that memory is not

necessarily more accurate or reliable, like this is the truth, as it were, but it is definitely more emotional and evocative we feel much more brought back to that original time and place and that is because of the part of the brain that's processing emotion and memory is the same part of the brain that's processing our conscious perception of scent so we're getting that blast of emotion and real memory sort of like recapitulation at the same time as we're getting that conscious, now I'm smelling Madeline Linden tea, or now I'm smelling the bubble bath from when I was seven years old, or whatever the case might be. But the other thing that's really important here, and I think really special is that we have millions and millions of different things that have happened to us in our

life. And the older we are, the more they accrue. I don't know how many of them we remember. And there are many of them, which we may never remember if it weren't for stumbling across a particular scent that brings you back to that particular time and place. So Proust actually writes like he had totally forgotten about this episode with his aunt in Cambrai. And it wasn't until he came to have this sort of reconnection with this sort of unique blend of Linden tea and madeleine cookie that he was brought back to that and all kinds of things like that can happen to us throughout our lives where we might never come across that same scent to bring us back to that same moment in time and that's further complicated by the fact that our interpretation of a scent is due to the context

that we're in when we're having the perceptual experience. So if Proust weren't actually having a biscuit and a cup of tea, sort of the same thing, but just somehow came across the aroma of Lyndon, Madeleine merged together, maybe if he was like walking down the street in Paris, he could think, oh, that's the scent of somebody's perfume or whatever it was and not be reminded of his aunt and his childhood because the context was so different. So we need a variety of things kind of overlay to bring the meaning to be the same to then bring us back to that moment in our past, which might otherwise be forever forgotten. So I think a way of really having a full life story is to be paying attention to scent throughout it so that it can

bring you back if you have the opportunity. But it seems like this kind of recognition also gives us something we can do to make memories a little bit more emotional, which is that we can add a scent. So I'm thinking, you know, maybe I'm going on a new vacation that I really want to remember, or maybe it's my wedding day

and I want to remember all the parts, like when I was getting dressed and what happened. The suggestion there that I never would have thought of before thinking about your research is that maybe if we bring in a particular smell, that'll make it easier later on to go back to exactly what we were feeling at those moments. Is that kind of what we see from the research? Absolutely. And I do this. I actually create sort of my own personal set memories for particular important episodes. So if I'm going on a special vacation, I will go to a fragrance store and go through a whole bunch of different fragrances, like pick out one that's something

that's unfamiliar. Obviously I have to like it too. And then for the period of that vacation, I wear that scent every day. And then I don't wear it after the vacation. And then when I want to be particularly reminded of it, I will smell it. Or if I want to like kind of reconjure the particular experience, I will wear it for a night or whatever the case might be. And then I am really brought back. Those are the scent snapshot to that experience, which is much more than just a visual. It's so much more emotional. Now, one thing that I do have to caution people about is this problem of adaptation and habituation where we stop being able to detect the scent if we overexpose ourselves to it. So, you know, if you think about if you wear a fragrance on a daily basis or if you use the same kind of scented lotion or whatever the case

might be, you may hardly smell that scent anymore or you barely smell it at all. That's why it's really important to be very sort of judicious and use sort of tiny amounts of cautious about overdoing it of only wearing it for a short period of time. So if I went away for a month, it would not be advisable for me necessarily be wearing this every day if I wanted to get the full bandwidth of that experience, because over that month, I'm going to stop really being able to be sensitive to smelling that fragrance. And so maybe the beginning of the month long trip, that's going to be highlighted for me, but the other parts that might fade out.. So for a short period of time and not doing it overboard, using a scent

to create a memory and then being able to come back to it. But you also can't be like smelling that perfume every day afterwards to remember the trip because then the genie will also leave the bottle. It seems like that kind of caveat also comes in when we start thinking about ways that we can use scents to feel better generally. Everybody's heard this term aromatherapy. Is this the kind of thing we can really use to feel better and improve our emotions in our daily life more generally? Yes, so absolutely. So I definitely recommend for people to find fragrances that they don't know from before. So not something that you already have an association to, that they don't know from before. So not something that you already have an association to,

something that is unfamiliar to you. And then specifically pair that with getting into some kind of positive emotional state. And like I said, you can have a whole apothecary, like get eight or 10 different fragrances and then get into particular emotional states and then smell those smells when you're in that state. And then when you want to get into that state, smell it again. So let's say I have a job interview that I'm really nervous about. I want to really do well. And I really want to feel confident and energized. Well, I have that scent that I was using when I was in this really confident, energized state. I then smell it before my job interview.

And then I can go in and give them the best. Or if I'm feeling really stressed out, and there's another scent that I've connected to feeling relaxed and soothed and, you know, chilling out and down vibes in a good way, then I can go and I can smell that. But the idea here is not to be doing it too much. Like you can't, this can't be your, like your daily drug of choice. You can't keep going back to it because the more you go back to it, the more two things happen. One, you will adapt to it, just not be able to smell it nearly as well. So the sensitivity to it will decrease. But it's also the case, like if you keep going back to the scent that makes you feel calm when you're in a frazzled state, over time, that scent

can also become connected to being frazzled. So it's sort of losing its benefit in that regard as well. I think another thing I find so weird about smell is that it's really hard to remember smells. Like I can image, you know, what my car looked like when I was a teenager, and I can kind of remember what that podcast sound like, you know, that I listened to last week or remember what someone's voice sounds like. But it's really hard to remember like a smell, like even very familiar smells, like baking cookies. I've smelled that a bunch in my life.

But when I try to image that in my brain, I like kind of can't. So it seems as though we don't actually have the capacity to in our brain's nose, keep stored the sensory representation. So the percept itself, so we can know things about it, like baking cookies.

We have all kinds of semantic information, visual information about it and so on and know that we really like it. But to really get that smell recapitulated at will, you know, just because I feel like it's this way you can visualize your car or think about the song and really hear it. We don't seem to be able to do that with smell.

Now, expert perfumers will argue with you that they can do it. And it is possible that they actually can, because one of the things that's really interesting about the sense of smell is the more experience we have with it, the greater sort of the neuroplasticity develops with it, so that people who spend their livelihood doing smelling can potentially be able to eventually store at least a certain amount of these representations to be able to call them up sort of perceptually at will. And it is the case that occasionally we will have dreams where we experience the perception of scent. We also know there's certain conditions like migraine or even epileptic seizures, which for certain individuals

are preceded by smelling something that isn't actually there. But for the average person with just a daily life experience, we don't seem to be carrying around all these stored representations. We know what the smell means. We know the feeling that it elicits as soon as we encounter it. We don't walk around with sort of the archive of all scents perceptually in our head. You've also argued that we need to make sure that we're using our smell well, that we kind of need to get practiced up on it and take it a little bit more seriously. So what are ways that we can kind of exercise our smell a little bit more in our daily lives? So having a good sense of smell is actually critical for a huge aspect of things in our life, our mental health, our physical health, not just the things we've been talking about today, like

emotion and memory and connection to other people, but literally the functioning of our life, our mental health, our physical health, not just the things we've been talking about today, like emotion and memory and connection to other people, but literally the functioning of our brain and our body. So people who have a healthy sense of smell are actually more likely to live longer. They have better cognitive health. They have better mental health overall. So having a good sense of smell is actually really important for the quality of our life and the quantity of our life. So lifespan and health span are really connected to a good functioning sense of smell. And there's ways that at any point in life, and unfortunately, like with our other senses, as we get older, our sense of smell tends to not be as strong and it's different for everybody.

But throughout our life, it's actually really beneficial to be exercising our nose. And how to do this is just, you know, on the most simple, basic level, just consciously every day to make a point to sniff something, not just sort of like habit hit you, but literally, you know, open up their cabinet and sniff the peanut butter or go and take that, you know, shampoo cap off and like sniff it, or, you know know find a couple of things like that now that's just the most simple thing to do or while you're walking your dog like i do like you walk by some flowers that smell nice like stop and actually smell the roses so beyond doing that if you are actually struggling to get a stronger sense of smell or if you've lost your sense of

smell and want to do something to regain it then you can do something more explicit called smell training and that involves getting four smells that are actually in this case, we want familiar smells, we want smells we have a positive connection to from the past. And whether we can smell them now or not, what you want to do is let's say one of them is peanut butter. So I think of peanut butter as well, I like the smell, but also after a workout is sort of like a go to set. So I'm going to smell peanut butter, I'm going to open the jar. So I'm going to smell peanut butter. I'm going to open the jar.

And I'm going to think about, this is my post-workout smell. Do it with another three others. So you want to have like four familiar smells. Do this at least two, if not three times a day. So you don't have to spend long with it. It does take a couple of minutes each time, but that's not that much of a time commitment. And over time, what you will see is that overall, your sense of smell should improve. Now, for people who've really lost their sense of smell

and they're doing this, one of the difficulties is the frustration that this is not an instantaneous, like I did it for a week and now I can smell again. And often it can take quite a bit of time. It might not work at all, but basically, give it three months. If nothing is happening

switch to another set of four familiar smells that you like and keep on trying and depending upon why you have smell loss it can actually be the case that this will really help regenerate it now it's not an absolute and it depends on how long it's been since you've lost your sense of smell how you lost your sense of smell this is more likely to be effective in things like post-viral smell loss, like with COVID, than it is if you had traumatic brain injury, like you were in some kind of an accident and you lost your sense of smell that way, that can be more difficult to regain. And it's also best if this is within the first year of having lost it rather than you start this 10 years later. But in any case, no matter what, this is making your brain stronger.

So even if you can't smell it, the act of active sniffing paired with thinking about what that should be is actually going to be good for your brain overall and good for your cognitive health. I hope you've enjoyed this quick journey into smell with my guest, Rachel Herz, and particularly her description of scent and attraction. It nicely sets us up for our next season of shows, because this Valentine's Day, we'll be looking of scent and attraction. It nicely sets us up for our next season of shows, because this Valentine's Day, we'll be looking at happiness and love. I think on our second date, John said, you know, I was in another relationship, but I've told her I'm not going to see her anymore. I immediately had a panic attack.

I was like, really? Already? So make a date and listen again to The Happiness Lab with me, Dr. Laurie Santos.