February 5, 2024 • 51 mins
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.
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Episode Transcript
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Speaker 1 (00:15):
Pushkin. Being a podcaster means you sometimes get some strange
and unexpected deliveries. You see, whenever I read an ad
for the show, it's only for a product that I
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
(00:37):
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,
(00:57):
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 missus Myers.
These sentence samples around at the absolute perfect time, because
over the past few months, I've gone on a bit
of an olfactory journey. It's a challenge I started after
I chatted with the Great Happiness Expert Gretchen Ruben.
Speaker 2 (01:19):
For some people, I think that this can be kind
of an overlooked sense.
Speaker 1 (01:23):
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.
Speaker 2 (01:40):
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
(02:04):
a scented candle.
Speaker 1 (02:06):
Who am I to argue with Gretchen Ruben? And so
I've been working hard to eliminate smells I don't like
and to introduce new sense that I do. But the
process of paying attention to the sense 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
(02:28):
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.
Speaker 3 (02:45):
I know you're talking about the sense of skunk, my
dirty secret pleasure.
Speaker 1 (02:51):
This is smell expert Rachel Hers.
Speaker 3 (02:53):
Which actually, since I have 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.
Speaker 1 (03:01):
Rachel's a neuroscientist who's been studying our sense of smell
for over thirty 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
(03:21):
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.
Speaker 3 (03:32):
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. It 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 all of a sudden, there's a
scent wafting into the car, and from the front seat,
(03:53):
my mom says, oh my, move that smell. Now, 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,
(04:16):
I love that smell, And people go ooh, grows, You're
so weird. That's disgusting that skunk. And I did not
know that that was a skunk first of all, and
b that everyone thought like pepe lapew, whether it's 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
(04:37):
sealed my fate as you know, 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 smelt skunk before but just seen the Peppy la
(04:58):
Pew cartoons, in which case I would have formed a
negative association to that skunk smells bad. It is supposed
to be bad, even without having ever smelled it. So
we have this sort of interaction between our personal experience
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
(05:19):
I had some friends from Sweden visiting me, actually all
faction experts as well, and we were walking down the
street near my house when I lived 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 breeze. So I
turned to my colleagues and I said, have you ever
smelled that before? And they go no, And I said,
(05:40):
so what do you think of it? They oh, it's okay,
it's interesting. It's like, well, what is that? So I
said that skunk and then they were like, oh, yeah, yeah,
what does that supposed to me? And then I said,
everybody here thinks it's awful or there's a post that
think is 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
(06:00):
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 dogs spray 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 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.
(06:23):
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 are all factory receptor expression,
and everybody's actually ever so slightly different from everyone else.
(06:45):
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, they're gonna
be like, oh, that's too much like perfume, for instance.
Speaker 1 (06:56):
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 in Lisa as an adult who's kind
of into smell.
Speaker 3 (07:07):
Oh yes, absolutely, very very to 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.
Speaker 1 (07:20):
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.
Speaker 3 (07:26):
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 drug store to
make sure that they like it. Are other kinds of
products like that that are definitely making a lot of
simple life choices based on how something smells to them,
(07:48):
and actually maybe even not so simple, maybe like your partner,
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 disc connect is, and
(08:09):
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 sent a couple of years ago, actually
so in the height of the pandemic, we collected the
data in the spring of twenty twenty one, developed a
survey to look at first of all, how people value
their sense of smell to hearing and vision, and then
(08:31):
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 and
the forty something group. And amongst the college students, twenty
(08:53):
five percent of them would give up their sense of
smell to keep their cell phone, and fifty percent 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 was someone 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.
(09:14):
And also because of the fact that although we didn't
really have a good comparison, point like to do this
in twenty eighteen and see the comparison. But I thought,
because there was so much media about smell loss and
about how people's story is about how awful it was
they're 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
(09:35):
sense of smell is actually more important than I thought
it was.
Speaker 1 (09:38):
And this kind of fits with what we see just
in the world. I mean, 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 smells that important.
Speaker 3 (09:54):
Well, so 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
five percent of your life's worth. Value example, if you
were in a compensation case, like you become blind or
you lose another sense, how much should you be compensated
(10:16):
for that? Well, vision you get eighty five percent of
whatever your salary might be extended out for the next
twenty years. Per smell you get anywhere between one and
five percent. So really sort of idealize as hardly important
at all. However, as a function of the pandemic and
also new technology, new innovation, there's actually various things in
(10:36):
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.
Speaker 1 (10:48):
And that's going to be really important because what I
learned from your book is that it really deeply affects
us in 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 old faction?
Speaker 3 (10:59):
So what is really shocking to people? And unfortunately, unless
you've had the experience, you really just don't realize. I mean,
multeple will say, oh yeah, well, food, I can see
how that involved. Or maybe I couldn't smell the gas leaks,
so there's certain like 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,
(11:21):
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 new mommy,
but everything else we experience when we're eating. So bacon,
for example, just taste like salt. The flavor is comprised
of one hundred and fifty different volatile organic compounds that
(11:41):
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
(12:01):
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. But you hug somebody,
even if just like at a certain proximity, maybe they
have a certain perfume or colone they usually wear. When
you smell that, that's like kind of bringing you intensely
(12:22):
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
(12:45):
the same part of the brain where emotion, memory, and
association is being formed. So the same brain areas 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 visceral, overwhelming,
(13:10):
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.
Speaker 1 (13:21):
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
(13:43):
another spot where we get old faction wrong.
Speaker 3 (13:45):
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
(14:07):
are basically at the level of our eyeb 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 a actually a tactile system
where for instance, if you're chopping onions, it makes your
eyes tier. If you're, you know, smelling mint, that cooling
sensation comes from trigeminal The hotness of a hot pepper
(14:30):
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,
(14:52):
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 you know, skunk is bad and roses 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
(15:14):
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 sort of eat
the food of that culture because of the fact that
it's actually been already pre exposed to that food before
(15:36):
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
(15:57):
or making a discussed looking face to vanilla. And then
you look a cross culturally and you also see huge
variation in what is considered good or bad. And we
really see this in a food. So like the idea
of man's meat is and other men's poisoned there really
comes from this massive effect of culture.
Speaker 1 (16:14):
One of the examples I loved was this interesting smell
of winter green 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.
Speaker 3 (16:24):
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 winter green smells good. It's like it's a mint,
it's a candy, it's paired with sugar. You know who
doesn't like winter green? But it turns out that in
the UK sort of like you know, if they give
us the United Kingdom the US, two countries separated by
a common language, what else is different between the two
(16:45):
of us. Well, people in the UK generally can't stand
the smell of winter green because their experience of it
comes from the scent of this analgesic bomb, so medicine,
and then nowadays actually winter green 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,
(17:07):
versus the US, where it's candy, and so really different
association positive in one case, negative.
Speaker 1 (17:13):
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 winter green in
the same way I do?
Speaker 2 (17:23):
Well.
Speaker 1 (17:23):
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 in some
of those all important ads. Neuroscientist Rachel Hers had to
(17:46):
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.
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
(18:07):
are some sense we'd happily ever smell again, Rachel suggests
we try to identify the smells that prompt a positive
reaction once we can turn to whenever we need a
little happiness boost her go to Fragrance is from a
childhood shampoo.
Speaker 3 (18:21):
We moved around a lot when I was a kid.
My parents were professors. We lived in Europe, we lived
in the US. We were bouncing around pretty much every
ten months, sometimes every six months for the first, you know,
six or seven years of my life. So at the
age of seven, we land in Montreal, and it was
it was tough with all that sort of moving around,
especially when I first started school. I come in as
(18:41):
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,
(19:03):
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, 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 a literally traveling salesman or door to
(19:25):
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 both nswered 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 know off the bat,
and I'm like, wait a second, wait a second, can
(19:45):
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 set.
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
(20:08):
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
(20:31):
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 piny 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
(20:51):
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. You know. This is a
great sadness that I'm never going to, you know, 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 eveclimb blue. That was another aspect
(21:12):
to the color was really intense and I thought that
it was something like Alga Marine 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 of, this bubble bath, and like, no, no,
(21:34):
that's not it. Anyway, fast forward to maybe and now
maybe like eight or nine years ago, I'm not exactly
sure what, but I was doing it 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 set 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,
(21:56):
was to go to this kind of old fashioned drug
store that has a little bit of everything. You know,
it has old shampoos, it has perfumes, it hadn't had
some floor to ceiling, all kinds of stuff. And I'm
in this drug store 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 eveclind blue and it has
(22:17):
the horseshoe on it, and I just like, oh my god,
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 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,
(22:38):
but it's actually Alga marine. Here's the bottle. I'm going
to open it up. I'm gonna give myself a little
boost of happiness. So it's just this phenomenal I'm so
I so love the 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.
(23:02):
Maybe actually that's one of the reasons why I love
the smell so much, because it's 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
(23:24):
might smell it and it could smell different to you.
So this is also we're all unique. Not only do
we have a unique body owner, we all have a
unique nose. So it smells everything slightly different to everyone.
But for me, this is the sort of spicy, sprucy
vanilla e kind of wonderfully blue bottle of algebraine.
Speaker 1 (23:43):
This is kind of the beauty of smell is that
it seems to get attached to particular context, but not
just kind of any context. It seems to really get
attached to emotional context. So talk about biologically why smell
does that so well.
Speaker 3 (23:55):
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 very central to the processing of smell,
as well as the hippocampus and other areas. That whole
(24:16):
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 use 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
(24:39):
do I like, what gives me joy? What am I
going to go towards, and what is bad for me?
What do I want to 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 skunk, that's caramel, and so on
is the amygdala hippochemical complex of the olympic system. So
(25:00):
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 primarial f cortex, like
we talked about the primary visual cortex, primary auditory cortex,
and so forth, the primarial factory cortex is the Amigdal
hippocampical complex, and.
Speaker 1 (25:18):
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 realize like, oh, I'm
spelling pine or I'm walking by and I start thinking
of my mom and I'm like, oh, that's lilax, which
is one of her favorite flowers. Like, is that why
the emotion seems to come so fast when we're experiencing
(25:40):
these smell memories.
Speaker 3 (25:41):
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. It's the two
(26:03):
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, h hum or. If the
sense 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
(26:26):
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 sense sort
of fleeting lead 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
(26:48):
ignored is because smells are invisible, and we are so
visually oriented as a species that we're always like, what
is that? Where is that? You know, point to this,
point to that, and so forth. You know, for the
data in the 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 is, you probably think most likely what
(27:10):
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.
Speaker 1 (27:27):
But that kind of means that 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.
Speaker 3 (27:38):
So what I would say is 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, enough,
nothing to smell here, rather than sort of have a
(27:58):
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 kind of floral send, not be able to
pinpoint it and 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
(28:19):
necessarily have realized that, but you still have that emotional connection,
so it does get under the hood that way.
Speaker 1 (28:24):
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 context like, for example, playing good or bad video games.
Tell me a little bit about this study.
Speaker 3 (28:39):
Yes, well, so we can engineer our own sense 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,
(29:01):
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've 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
(29:22):
connected to something that you have in association too, 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
(29:44):
encountered it. So like the first time you encounter whatever
it is is going to be what sticks. That we
experienced so much in childhood, that tends to be why
we're taken back to child so often. 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 two dollars and
(30:05):
fifty cents. And these were brown students, so they're highly motivated.
They want to get a plus on everything. So he said,
depending upon how good you had nothing to do with skill,
but how good you are, you can double your money
in five minutes by playing this game, and you know,
five dollars against a trivial amount. Losing two dollars and
fifty cents, however, believe it or not, is really draumatizing.
But also because the computer would make these noises like aunt,
(30:28):
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 in something. So after this association
(30:50):
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 set that was equally unfamiliar,
so that perfumer came up with a couple of different
fragrances or people were assigned these other tasks in a
room that was uncented. And what we found on these
series of subsequent tasks when that scent that was associated
(31:11):
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. By performance,
to be good has to be also motivated, like I
have to want to succeed and achieve. So I could
(31:33):
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.
Speaker 1 (31:47):
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 alfaction,
I really have the strong sense that smell matters a
lot for attraction. What does the science actually tell us.
Speaker 3 (32:05):
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
(32:26):
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 relationship smell is
(32:48):
also important, but it doesn't quite have the same navigation
in terms of why in 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.
So are propagation and based on the idea that we're
all here just to replicate and get our genes out
into future generation. And as a function of that, there's
(33:10):
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 period 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
(33:33):
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
(33:55):
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 throw and then have children herself,
and then go on and perpetuate your genes into subsequent generation.
But the other piece of this story is that that
(34:16):
child be healthy, and what determines your health will 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 says unique
as your fingerprint. This is how the tracking dog finds
(34:38):
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
(35:00):
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, 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 enter Z
and that will ensure that the children I have with
(35:22):
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,
(35:43):
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 Q. 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
(36:04):
recessive traits to be manifested, which can lead to, you know,
terrible diseases that don't allow for thriving, surviving and having
children yourself.
Speaker 1 (36:12):
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
(36:32):
smelling guy out there. Every single one of us thinks
is like really old, factor really hot. Yeah. Absolutely, It's
kind of different for everybody, which is cool.
Speaker 3 (36:40):
Yes, So, as a female looking for my ideal scent
match male, in terms of this whole being heterosexual reproduction,
there's no brad pit of smells. There's going to be
a different brad pit 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
(37:01):
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 to
hug from this person, but that's different from I want
to have sex with this person. So there is this
difference between wanting someone sexually versus wanting someone emotionally, although
(37:23):
they too can also become the same when we're in
an intimate, long term relationship with someone.
Speaker 1 (37:29):
In case you were wondering, I googled bread pit, 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 atcent 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
(37:54):
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 and Marcel
proosts in Search for Lost Time. The story's narrator has
just dipped a Madeline cake into a cup of tea
and taken a bite. The scent of that magical combination
(38:15):
of tea and cake sends Prus'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 it's brevity illusory.
This is perhaps the greatest ever description of how our
senses can briefly transport us to a whole other plane
(38:37):
of joyful existence. It's a passage that always intrigued Rachel Hers,
even prompting the neuroscientist to carry out her own research
on how smell and memory mix.
Speaker 3 (38:46):
So there's a couple of things that are going on
in Prus's description of his Madeline Biscuit and lind and
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
(39:07):
flavor can call in before he ever gets to and
like literally pages before he gets to my aunt's house, Incumbra,
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
(39:29):
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
and so forth, I found that when we have a
memory that's triggered by ascent, that memory is not necessarily
more accurate or reliable like this is, you know, the truth,
(39:51):
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 conscience perception of
sent So we're getting that blast of emotion and real
memory sort of like recapitulation at the same time as
(40:12):
we're getting that conscious Now I'm smelling Madeleine and 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
(40:32):
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 Proofs
actually writes like he had totally forgotten about this episode
with his aunt and Combra, 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
(40:54):
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 Proofs weren't
actually having a biscuit and a cup of tea sort
(41:16):
of the same thing, but just somehow came across the
aroma of Lindon matt Len 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
(41:39):
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 cents throughout
it so that it can bring you back if you
have the opportunity.
Speaker 1 (41:53):
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
(42:15):
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.
Speaker 3 (42:23):
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
(42:43):
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 because the set snapshot
to that experience, which is much more than just a visual.
(43:06):
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 over expose 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
(43:27):
smell it at all. That's why it's really important to
be very sort of judicious and use sort of tiny amounts,
sort 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 want
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
(43:49):
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.
Speaker 1 (44:08):
It seems like that kind of caveat also comes in
when we start thinking about ways that we can use
sense to feel better. Generally, you know, everybody's heard this
term of romatherapy. Is this the kind of thing we
can really use to feel better and improve our emotions
in our daily life more generally?
Speaker 3 (44:24):
Yes, so absolutely so. I definitely recommend for people to
find fragrances that they don't know from before, so not
something 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
(44:45):
ten 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 and I want to
really do well, and I really want to feel confident
and energized. Well I have that sense that I was
using when I was in this really confident, energized state.
(45:08):
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 ice and 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
(45:30):
drug of choice. You can't keep going back to it
because the more you go back to it, the more
two things happen. When you will adapt to it just
not be able to smell it nearly as well, So
the sensitivity to a 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,
(45:51):
So it's sort of losing its benefit in that regard
as well.
Speaker 1 (45:55):
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 looks like when
I was a teenager, and I can kind of remember
what that podcast sound like, you know that I listened
to you 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
(46:17):
a bunch in my life, but when I try to
image that in my brain, I like kind of can't.
Speaker 3 (46:23):
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
(46:43):
recapitulated at will, you know, just because I feel like
it's this the 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
(47:04):
greater 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 perceptually. It will,
and it is the case that occasionally we will have
dreams where we experience the perception of scent. Also know
(47:26):
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, who 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
(47:46):
the archive of all sense perceptually in our head.
Speaker 1 (47:50):
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.
Speaker 3 (48:02):
So having a good sense of smell is actually critical
for a huge aspect of this 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 brain
and our body. So people who have a healthy health
sense of smell are actually more likely to live longer,
(48:23):
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, i
like with our other senses, as we get older, our
(48:45):
sense of smell tends to not be as strong and
it's different for everybody, but throughout our life'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 that like have it hit you, but literally,
you know, open up their cabinet and sniff the peanut butter,
(49:07):
or go and take that you know, shampoo cap off
and like sniff it, or you 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
(49:27):
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,
(49:48):
but also after a workout is sort of like a
go to scent. 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,
(50:09):
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 your 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,
(50:30):
but basically, you know, give it three months if nothing
is happening, switched 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
(50:51):
lost your sense of smell. This is more likely to
be effective in things like post viral smell lost 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 ten years later. But in
any case, no matter what, this is making your brain stronger.
(51:14):
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.
Speaker 1 (51:25):
I hope you've enjoyed this quick journey and to smell
with my guest Rachel Hers, 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 at happiness and love.
Speaker 3 (51:39):
Oh 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. And I immediately had
a pianic tab. It was like, really already
Speaker 1 (51:52):
So make a date and listen again to the Happiness
Lab with me, Doctor Laurie Santos
Pushkin. Being a podcaster means you sometimes get some strange
and unexpected deliveries. You see, whenever I read an ad
for the show, it's only for a product that I
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
(00:37):
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,
(00:57):
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 missus Myers.
These sentence samples around at the absolute perfect time, because
over the past few months, I've gone on a bit
of an olfactory journey. It's a challenge I started after
I chatted with the Great Happiness Expert Gretchen Ruben.
Speaker 2 (01:19):
For some people, I think that this can be kind
of an overlooked sense.
Speaker 1 (01:23):
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.
Speaker 2 (01:40):
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
(02:04):
a scented candle.
Speaker 1 (02:06):
Who am I to argue with Gretchen Ruben? And so
I've been working hard to eliminate smells I don't like
and to introduce new sense that I do. But the
process of paying attention to the sense 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
(02:28):
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.
Speaker 3 (02:45):
I know you're talking about the sense of skunk, my
dirty secret pleasure.
Speaker 1 (02:51):
This is smell expert Rachel Hers.
Speaker 3 (02:53):
Which actually, since I have 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.
Speaker 1 (03:01):
Rachel's a neuroscientist who's been studying our sense of smell
for over thirty 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
(03:21):
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.
Speaker 3 (03:32):
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. It 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 all of a sudden, there's a
scent wafting into the car, and from the front seat,
(03:53):
my mom says, oh my, move that smell. Now, 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,
(04:16):
I love that smell, And people go ooh, grows, You're
so weird. That's disgusting that skunk. And I did not
know that that was a skunk first of all, and
b that everyone thought like pepe lapew, whether it's 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
(04:37):
sealed my fate as you know, 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 smelt skunk before but just seen the Peppy la
(04:58):
Pew cartoons, in which case I would have formed a
negative association to that skunk smells bad. It is supposed
to be bad, even without having ever smelled it. So
we have this sort of interaction between our personal experience
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
(05:19):
I had some friends from Sweden visiting me, actually all
faction experts as well, and we were walking down the
street near my house when I lived 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 breeze. So I
turned to my colleagues and I said, have you ever
smelled that before? And they go no, And I said,
(05:40):
so what do you think of it? They oh, it's okay,
it's interesting. It's like, well, what is that? So I
said that skunk and then they were like, oh, yeah, yeah,
what does that supposed to me? And then I said,
everybody here thinks it's awful or there's a post that
think is 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
(06:00):
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 dogs spray 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 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.
(06:23):
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 are all factory receptor expression,
and everybody's actually ever so slightly different from everyone else.
(06:45):
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, they're gonna
be like, oh, that's too much like perfume, for instance.
Speaker 1 (06:56):
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 in Lisa as an adult who's kind
of into smell.
Speaker 3 (07:07):
Oh yes, absolutely, very very to 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.
Speaker 1 (07:20):
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.
Speaker 3 (07:26):
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 drug store to
make sure that they like it. Are other kinds of
products like that that are definitely making a lot of
simple life choices based on how something smells to them,
(07:48):
and actually maybe even not so simple, maybe like your partner,
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 disc connect is, and
(08:09):
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 sent a couple of years ago, actually
so in the height of the pandemic, we collected the
data in the spring of twenty twenty one, developed a
survey to look at first of all, how people value
their sense of smell to hearing and vision, and then
(08:31):
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 and
the forty something group. And amongst the college students, twenty
(08:53):
five percent of them would give up their sense of
smell to keep their cell phone, and fifty percent 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 was someone 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.
(09:14):
And also because of the fact that although we didn't
really have a good comparison, point like to do this
in twenty eighteen and see the comparison. But I thought,
because there was so much media about smell loss and
about how people's story is about how awful it was
they're 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
(09:35):
sense of smell is actually more important than I thought
it was.
Speaker 1 (09:38):
And this kind of fits with what we see just
in the world. I mean, 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 smells that important.
Speaker 3 (09:54):
Well, so 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
five percent of your life's worth. Value example, if you
were in a compensation case, like you become blind or
you lose another sense, how much should you be compensated
(10:16):
for that? Well, vision you get eighty five percent of
whatever your salary might be extended out for the next
twenty years. Per smell you get anywhere between one and
five percent. So really sort of idealize as hardly important
at all. However, as a function of the pandemic and
also new technology, new innovation, there's actually various things in
(10:36):
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.
Speaker 1 (10:48):
And that's going to be really important because what I
learned from your book is that it really deeply affects
us in 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 old faction?
Speaker 3 (10:59):
So what is really shocking to people? And unfortunately, unless
you've had the experience, you really just don't realize. I mean,
multeple will say, oh yeah, well, food, I can see
how that involved. Or maybe I couldn't smell the gas leaks,
so there's certain like 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,
(11:21):
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 new mommy,
but everything else we experience when we're eating. So bacon,
for example, just taste like salt. The flavor is comprised
of one hundred and fifty different volatile organic compounds that
(11:41):
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
(12:01):
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. But you hug somebody,
even if just like at a certain proximity, maybe they
have a certain perfume or colone they usually wear. When
you smell that, that's like kind of bringing you intensely
(12:22):
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
(12:45):
the same part of the brain where emotion, memory, and
association is being formed. So the same brain areas 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 visceral, overwhelming,
(13:10):
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.
Speaker 1 (13:21):
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
(13:43):
another spot where we get old faction wrong.
Speaker 3 (13:45):
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
(14:07):
are basically at the level of our eyeb 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 a actually a tactile system
where for instance, if you're chopping onions, it makes your
eyes tier. If you're, you know, smelling mint, that cooling
sensation comes from trigeminal The hotness of a hot pepper
(14:30):
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,
(14:52):
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 you know, skunk is bad and roses 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
(15:14):
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 sort of eat
the food of that culture because of the fact that
it's actually been already pre exposed to that food before
(15:36):
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
(15:57):
or making a discussed looking face to vanilla. And then
you look a cross culturally and you also see huge
variation in what is considered good or bad. And we
really see this in a food. So like the idea
of man's meat is and other men's poisoned there really
comes from this massive effect of culture.
Speaker 1 (16:14):
One of the examples I loved was this interesting smell
of winter green 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.
Speaker 3 (16:24):
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 winter green smells good. It's like it's a mint,
it's a candy, it's paired with sugar. You know who
doesn't like winter green? But it turns out that in
the UK sort of like you know, if they give
us the United Kingdom the US, two countries separated by
a common language, what else is different between the two
(16:45):
of us. Well, people in the UK generally can't stand
the smell of winter green because their experience of it
comes from the scent of this analgesic bomb, so medicine,
and then nowadays actually winter green 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,
(17:07):
versus the US, where it's candy, and so really different
association positive in one case, negative.
Speaker 1 (17:13):
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 winter green in
the same way I do?
Speaker 2 (17:23):
Well.
Speaker 1 (17:23):
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 in some
of those all important ads. Neuroscientist Rachel Hers had to
(17:46):
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.
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
(18:07):
are some sense we'd happily ever smell again, Rachel suggests
we try to identify the smells that prompt a positive
reaction once we can turn to whenever we need a
little happiness boost her go to Fragrance is from a
childhood shampoo.
Speaker 3 (18:21):
We moved around a lot when I was a kid.
My parents were professors. We lived in Europe, we lived
in the US. We were bouncing around pretty much every
ten months, sometimes every six months for the first, you know,
six or seven years of my life. So at the
age of seven, we land in Montreal, and it was
it was tough with all that sort of moving around,
especially when I first started school. I come in as
(18:41):
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,
(19:03):
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, 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 a literally traveling salesman or door to
(19:25):
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 both nswered 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 know off the bat,
and I'm like, wait a second, wait a second, can
(19:45):
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 set.
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
(20:08):
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
(20:31):
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 piny 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
(20:51):
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. You know. This is a
great sadness that I'm never going to, you know, 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 eveclimb blue. That was another aspect
(21:12):
to the color was really intense and I thought that
it was something like Alga Marine 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 of, this bubble bath, and like, no, no,
(21:34):
that's not it. Anyway, fast forward to maybe and now
maybe like eight or nine years ago, I'm not exactly
sure what, but I was doing it 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 set 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,
(21:56):
was to go to this kind of old fashioned drug
store that has a little bit of everything. You know,
it has old shampoos, it has perfumes, it hadn't had
some floor to ceiling, all kinds of stuff. And I'm
in this drug store 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 eveclind blue and it has
(22:17):
the horseshoe on it, and I just like, oh my god,
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 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,
(22:38):
but it's actually Alga marine. Here's the bottle. I'm going
to open it up. I'm gonna give myself a little
boost of happiness. So it's just this phenomenal I'm so
I so love the 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.
(23:02):
Maybe actually that's one of the reasons why I love
the smell so much, because it's 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
(23:24):
might smell it and it could smell different to you.
So this is also we're all unique. Not only do
we have a unique body owner, we all have a
unique nose. So it smells everything slightly different to everyone.
But for me, this is the sort of spicy, sprucy
vanilla e kind of wonderfully blue bottle of algebraine.
Speaker 1 (23:43):
This is kind of the beauty of smell is that
it seems to get attached to particular context, but not
just kind of any context. It seems to really get
attached to emotional context. So talk about biologically why smell
does that so well.
Speaker 3 (23:55):
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 very central to the processing of smell,
as well as the hippocampus and other areas. That whole
(24:16):
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 use 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
(24:39):
do I like, what gives me joy? What am I
going to go towards, and what is bad for me?
What do I want to 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 skunk, that's caramel, and so on
is the amygdala hippochemical complex of the olympic system. So
(25:00):
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 primarial f cortex, like
we talked about the primary visual cortex, primary auditory cortex,
and so forth, the primarial factory cortex is the Amigdal
hippocampical complex, and.
Speaker 1 (25:18):
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 realize like, oh, I'm
spelling pine or I'm walking by and I start thinking
of my mom and I'm like, oh, that's lilax, which
is one of her favorite flowers. Like, is that why
the emotion seems to come so fast when we're experiencing
(25:40):
these smell memories.
Speaker 3 (25:41):
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. It's the two
(26:03):
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, h hum or. If the
sense 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
(26:26):
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 sense sort
of fleeting lead 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
(26:48):
ignored is because smells are invisible, and we are so
visually oriented as a species that we're always like, what
is that? Where is that? You know, point to this,
point to that, and so forth. You know, for the
data in the 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 is, you probably think most likely what
(27:10):
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.
Speaker 1 (27:27):
But that kind of means that 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.
Speaker 3 (27:38):
So what I would say is 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, enough,
nothing to smell here, rather than sort of have a
(27:58):
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 kind of floral send, not be able to
pinpoint it and 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
(28:19):
necessarily have realized that, but you still have that emotional connection,
so it does get under the hood that way.
Speaker 1 (28:24):
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 context like, for example, playing good or bad video games.
Tell me a little bit about this study.
Speaker 3 (28:39):
Yes, well, so we can engineer our own sense 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,
(29:01):
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've 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
(29:22):
connected to something that you have in association too, 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
(29:44):
encountered it. So like the first time you encounter whatever
it is is going to be what sticks. That we
experienced so much in childhood, that tends to be why
we're taken back to child so often. 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 two dollars and
(30:05):
fifty cents. And these were brown students, so they're highly motivated.
They want to get a plus on everything. So he said,
depending upon how good you had nothing to do with skill,
but how good you are, you can double your money
in five minutes by playing this game, and you know,
five dollars against a trivial amount. Losing two dollars and
fifty cents, however, believe it or not, is really draumatizing.
But also because the computer would make these noises like aunt,
(30:28):
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 in something. So after this association
(30:50):
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 set that was equally unfamiliar,
so that perfumer came up with a couple of different
fragrances or people were assigned these other tasks in a
room that was uncented. And what we found on these
series of subsequent tasks when that scent that was associated
(31:11):
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. By performance,
to be good has to be also motivated, like I
have to want to succeed and achieve. So I could
(31:33):
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.
Speaker 1 (31:47):
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 alfaction,
I really have the strong sense that smell matters a
lot for attraction. What does the science actually tell us.
Speaker 3 (32:05):
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
(32:26):
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 relationship smell is
(32:48):
also important, but it doesn't quite have the same navigation
in terms of why in 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.
So are propagation and based on the idea that we're
all here just to replicate and get our genes out
into future generation. And as a function of that, there's
(33:10):
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 period 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
(33:33):
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
(33:55):
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 throw and then have children herself,
and then go on and perpetuate your genes into subsequent generation.
But the other piece of this story is that that
(34:16):
child be healthy, and what determines your health will 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 says unique
as your fingerprint. This is how the tracking dog finds
(34:38):
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
(35:00):
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, 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 enter Z
and that will ensure that the children I have with
(35:22):
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,
(35:43):
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 Q. 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
(36:04):
recessive traits to be manifested, which can lead to, you know,
terrible diseases that don't allow for thriving, surviving and having
children yourself.
Speaker 1 (36:12):
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
(36:32):
smelling guy out there. Every single one of us thinks
is like really old, factor really hot. Yeah. Absolutely, It's
kind of different for everybody, which is cool.
Speaker 3 (36:40):
Yes, So, as a female looking for my ideal scent
match male, in terms of this whole being heterosexual reproduction,
there's no brad pit of smells. There's going to be
a different brad pit 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
(37:01):
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 to
hug from this person, but that's different from I want
to have sex with this person. So there is this
difference between wanting someone sexually versus wanting someone emotionally, although
(37:23):
they too can also become the same when we're in
an intimate, long term relationship with someone.
Speaker 1 (37:29):
In case you were wondering, I googled bread pit, 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 atcent 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
(37:54):
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 and Marcel
proosts in Search for Lost Time. The story's narrator has
just dipped a Madeline cake into a cup of tea
and taken a bite. The scent of that magical combination
(38:15):
of tea and cake sends Prus'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 it's brevity illusory.
This is perhaps the greatest ever description of how our
senses can briefly transport us to a whole other plane
(38:37):
of joyful existence. It's a passage that always intrigued Rachel Hers,
even prompting the neuroscientist to carry out her own research
on how smell and memory mix.
Speaker 3 (38:46):
So there's a couple of things that are going on
in Prus's description of his Madeline Biscuit and lind and
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
(39:07):
flavor can call in before he ever gets to and
like literally pages before he gets to my aunt's house, Incumbra,
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
(39:29):
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
and so forth, I found that when we have a
memory that's triggered by ascent, that memory is not necessarily
more accurate or reliable like this is, you know, the truth,
(39:51):
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 conscience perception of
sent So we're getting that blast of emotion and real
memory sort of like recapitulation at the same time as
(40:12):
we're getting that conscious Now I'm smelling Madeleine and 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
(40:32):
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 Proofs
actually writes like he had totally forgotten about this episode
with his aunt and Combra, 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
(40:54):
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 Proofs weren't
actually having a biscuit and a cup of tea sort
(41:16):
of the same thing, but just somehow came across the
aroma of Lindon matt Len 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
(41:39):
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 cents throughout
it so that it can bring you back if you
have the opportunity.
Speaker 1 (41:53):
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
(42:15):
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.
Speaker 3 (42:23):
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
(42:43):
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 because the set snapshot
to that experience, which is much more than just a visual.
(43:06):
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 over expose 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
(43:27):
smell it at all. That's why it's really important to
be very sort of judicious and use sort of tiny amounts,
sort 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 want
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
(43:49):
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.
Speaker 1 (44:08):
It seems like that kind of caveat also comes in
when we start thinking about ways that we can use
sense to feel better. Generally, you know, everybody's heard this
term of romatherapy. Is this the kind of thing we
can really use to feel better and improve our emotions
in our daily life more generally?
Speaker 3 (44:24):
Yes, so absolutely so. I definitely recommend for people to
find fragrances that they don't know from before, so not
something 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
(44:45):
ten 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 and I want to
really do well, and I really want to feel confident
and energized. Well I have that sense that I was
using when I was in this really confident, energized state.
(45:08):
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 ice and 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
(45:30):
drug of choice. You can't keep going back to it
because the more you go back to it, the more
two things happen. When you will adapt to it just
not be able to smell it nearly as well, So
the sensitivity to a 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,
(45:51):
So it's sort of losing its benefit in that regard
as well.
Speaker 1 (45:55):
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 looks like when
I was a teenager, and I can kind of remember
what that podcast sound like, you know that I listened
to you 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
(46:17):
a bunch in my life, but when I try to
image that in my brain, I like kind of can't.
Speaker 3 (46:23):
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
(46:43):
recapitulated at will, you know, just because I feel like
it's this the 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
(47:04):
greater 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 perceptually. It will,
and it is the case that occasionally we will have
dreams where we experience the perception of scent. Also know
(47:26):
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, who 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
(47:46):
the archive of all sense perceptually in our head.
Speaker 1 (47:50):
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.
Speaker 3 (48:02):
So having a good sense of smell is actually critical
for a huge aspect of this 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 brain
and our body. So people who have a healthy health
sense of smell are actually more likely to live longer,
(48:23):
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, i
like with our other senses, as we get older, our
(48:45):
sense of smell tends to not be as strong and
it's different for everybody, but throughout our life'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 that like have it hit you, but literally,
you know, open up their cabinet and sniff the peanut butter,
(49:07):
or go and take that you know, shampoo cap off
and like sniff it, or you 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
(49:27):
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,
(49:48):
but also after a workout is sort of like a
go to scent. 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,
(50:09):
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 your 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,
(50:30):
but basically, you know, give it three months if nothing
is happening, switched 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
(50:51):
lost your sense of smell. This is more likely to
be effective in things like post viral smell lost 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 ten years later. But in
any case, no matter what, this is making your brain stronger.
(51:14):
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.
Speaker 1 (51:25):
I hope you've enjoyed this quick journey and to smell
with my guest Rachel Hers, 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 at happiness and love.
Speaker 3 (51:39):
Oh 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. And I immediately had
a pianic tab. It was like, really already
Speaker 1 (51:52):
So make a date and listen again to the Happiness
Lab with me, Doctor Laurie Santos
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