Date: Cool, yeah. So where are you from?
Tina: I'm from Genovia
Waitress: Welcome to the Why Am I Like This restaurant. Today's
special is existential dread with a little bit of crying on
the side. We're just really excited to have you here.
Tina: Is it me, Jesus?
Waitress: when you guys are ready, we'll come and check on—
Tina: what are you wearing? It smells interesting.
Date: Glad you're asked actually. This is my musk.
Tina: hmmm... what???
Date: I just got done pumping some iron before this and want
to gets some pheromones out there.
Tina: why?
Date: Well, research has shown that most females are attracted
to the pheromones smell of an alpha.
Tina: Research has shown? Okay, I'd like to see your citations
for that. I mean, do you really think we evolved the ability to
smell so we could get some of this action over here? But Ole
Musk does bring up a good point. Clearly, we have the ability to
generate some interesting fragrances, but more
importantly, we have the ability to detect them. And that really
makes me wonder, why do I smell? Why am I like this?
Date: Yeah, so it's like pretty simple. If you think about it.
Evolution gave us a sense of smell so that females could
detect when they're in the presence of a real alpha.
Tina: Okay, this guy has no idea what he's talking about.
Evolution? Simple? To understand why humans might have evolved
smell, we first need to understand what smell is and how
it works.
Date: Yeah, so like, a lot of times when I'm bench pressing, I
like to get down in there, get really close to the chest.
[muffled chatter]
Tina: With smell, aka olfaction, it takes two to tango. It
involves an odor and the ability to sense that odor. An odor is
really just a particle that's volatile enough that it can
travel up through our nostrils. When the particles make it all
the way to the back of our nose. They hit a special patch of
tissue called the olfactory epithelium, which contains
olfactory receptor cells. These are basically specialized
neurons that act like nostril tastebuds. They have branching
projections that poke out into the mucus of your epithelium. At
the end of these wriggly boys are the receptors that are
responsible for the function of funk. Each of these receptors
has a special shape that allows them to bind to particular
particles. Humans have around 400 Different olfactory
receptors, but we can smell way more than just 400 smells
because there isn't a one to one relationship between odor
molecules and receptors. Some receptors can fit multiple
molecules. But more importantly, smells are complex. What we file
away as a single smell actually triggers multiple receptors at a
time. For example—
Cheese! I love cheese. Cheese isn't actually a single coherent
smell. It's a range of various combinations of chemical
compounds that my brain has mentally filed away as cheese,
aka, currently the only source of joy in my life. It contains
esters, aldehydes, methyl ketones, and sulfur compounds.
And each of these volatile compounds binds to a set of
olfactory receptors. But the magic doesn't stop there. Once
these receptor cells are triggered, they send a signal up
to a meeting point where multiple olfactory neurons
converge before collectively sending a message for your brain
to decipher. And like a smelly symphony, it's the combination
of all these signals going off at once that creates the
experience of smelling cheese. But that experience can be
different depending on your mental associations with cheese.
For example, I associate cheese with pure unadulterated joy and
my childhood in Europe. However, some of us don't have such a
GOUDA memories of it.
Date: Yeah, I actually hate the smell of cheese because it
reminds me of my cat who choked on a piece of cheese.
Tina: Oh my god, I'm so sorry.
Date: Oh that's not how she died. She actually got hit by a
car. But she had trust issues. And every time people brought
cheese in the house, she would hiss. It's kind of stressful for me
Tina: Speaking of childhood trauma, obviously, some of us
have emotions entangled with certain aromatic associations.
But why? Well, it goes back to what that smell signal does in
your brain. The olfactory message communicated to your
brain is delivered at several stations. Some of these regions
of the brain, like the olfactory cortex are involved in
identifying and categorizing smell. Others, like the amygdala
and hippocampus are involved in emotional processing, which is
why smells can be associated with extremely happy or
extremely sad events in your life.
Date: Mr. Whiskers *cries* I miss her so much.
Tina: But it's not as simple as your emotional state equals
whether you like the smells around you or not. For example,
I might be in a fantastic mood and get a whiff of this guy over
here and it will still be disgusting. So, how does it
work? I've never met this guy before, so I can't blame him
personally for a bad smell association. But how did my
brain decide that something smelled bad? Do certain things
inherently smell good or bad? Or is that something that we learn?
Well, there's a whole area of study around the development of
odor preferences and aversions. What scientists have found is
that there's a complex process involved in developing the full
adult Rolodex of smells in relation to whether we should
approach them or avoid them. This series of determinations
that smell helps us make: what is this smell? Do I like it?
Should I avoid it? Is actually incredibly important across the
entire animal kingdom. For example, African elephants can
detect mines as they migrate through past war zones. Wolves
can use their noses to detect other animals more than a mile
away. And we've managed to train dogs to somehow smell everything
from bombs to cancer. And of course, some animals like moths
can secrete and smell pheromones, and they use this to
find mates. But does this work for humans too? A lot of people
like this guy, believe humans release these magical molecules
to somehow attract others to us. But that's not how pheromones work.
*whistle*
Pheromones are chemicals that many animals can secrete in
order to communicate with each other. A lot of people associate
pheromones exclusively with sexual attraction. But different
species can use them for different purposes. They can
signal anything from "This is my territory" to "Help me!" But
it's true that a lot of species use pheromones to say "hey, are
you down to *wink wink*" Now what makes a pheromone different
from a regular smell is that it elicits a particular kind of
behavioral or physiological response. So how do scientists
identify a pheromone? Well, it starts with an observation. If
scientists observe animal behavior they think might be
caused by a smell signal, they start investigating.
They first isolate the compound they think might be responsible.
Then synthesize it and do a bunch of experiments to see
whether it causes the same reaction that they first
observed. Many mammals and reptiles have a special
structure called a vomeronasal organ, which is dedicated to
sensing these pheromones and communicating that signal to the
brain. Funnily enough, the vomeronasal organ can be found
in human fetuses, but it's completely atrophied and non
functional by the time we become adults. This isn't too
surprising. If you think about the relatively small role that
smell plays for humans. Compared to other species. Like our
primate cousins, we evolved to be a very visual species and for
humans in particular, speech is an especially important trait.
If you think about it, visual impairment and blindness are
considered disabilities as is hearing impairment and deafness.
The world is pretty hostile towards people with these kinds
of disabilities the way most humans choose to communicate
exclude such people from fully participating in many
activities. But what happens to people who have a diminished
sense of smell or no sense of smell at all? Well, this
impairment called anosmia, might not hinder their direct
communication with other people. But it turns out that even
though smell isn't the star of the sensory show, it is a really
important supporting character.
You know how ranke Milk smells when it goes bad? You sniff that
and you get the message loud and clear that this needs to go
right down the drain, but someone dealing with anosmia
might not and then they'd be dealing with food poisoning. I
don't know if you've ever smelled a gas leak, but that
stuff stinks—like rotten eggs. No, literally. Gas companies add
a chemical called mercaptan because natural gas actually
doesn't have a smell. So the stench is purposefully built in
by humans as a warning signal. But if you can't smell then you
might not know until it's too late. It's no wonder that
anosmia is recognized as an invisible disability. The way
that smell serves as an alarm system is clearly important
enough, but there are even more reasons why evolution has kept
our sense of smell around. You know how happy you get when you
taste your favorite food. It's a whole experience. You smell the
sweet aroma of your favorite pie. Your mouth starts
salivating and your body is ready for this.
Date: Oh my God, my mom used to make the best sweet potato pie
when I was a kid. You like pie?
Tina: I love pie. I make it all the time.
Date: This is so good *eating noises*
Tina: Yeah. Oh, I am so glad you're enjoying that. I—
Date: Really good.
Tina: You'd be surprised how much of your sense of taste is
actually tied to smell. Once the food is in your mouth, aroma
molecules drift up through the retronasal passage near the back
of your throat where they're treated the same as smells that
came in through the nostrils. Without smell some flavors, like
cinnamon, actually wouldn't taste like cinnamon. They'd just
taste bitter. And if we lose our ability to smell then eating
becomes a sad and confusing experience, which is what
happened to a lot of those who lost their sense of smell
because of COVID. The key role of smell and the sensory
experience of food is what motivates a lot of us to eat and
let's face it, food makes you happy. Okay, so our sense of
smell might not be able to help us pick out the alphas in the
dating scene. But it does add to every aspect and
experience of our life.
You know what? I might have been a little harsh on him. After
reflecting on this and why our ancestors evolved the sense of
smell. I really think I should you know, enjoy myself a little
bit more. Stop and smell the roses
But damn. These roses really smell like—
*barking noises*
Sorry
back with a little bit of wine.
Stephanie, what happened?
I'm so glad that you're enjoying yourself.
Weak! Sorry
*tiny and sad burp*
Tina: That was great. That was fantastic.
Off camera: the tiniest little belch ever!