September 7, 2021 • 49 mins
What are tears? Are humans indeed the only animal that wraps and what purpose do they serve? In this episode of Stuff to Blow Your Mind, Robert and Joe explore the topic of tears from a scientific and even religious standpoint.
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Speaker 1 (00:00):
My Welcome to Stuff to Blow Your Mind production of
My Heart Radio. Hey, welcome to Stuff to Blow Your Mind.
My name is Robert Lamb and I'm Joe McCormick. And
today we're going to be kicking off the first episode
(00:21):
in a series about the subject of tears. This is
something I've gotten really interested in in the last couple
of weeks, Questions about the biological origins of crying and
things like that. But before we get started to set
the mood, I wanted to to read a poem by
Walt Whitman that's all about tears. In fact, it's so
much about tears. It just has the word tears followed
(00:44):
by an exclamation point, like at least six or seven times.
All Right, you ready for Grandpa Wald, Let's do it,
hit it? Okay. The poem goes tears, Tears, Tears in
the night in solitude, Tears on the white shore, dripping, dripping,
sucked in by the sand. Tears not a star shining,
(01:04):
all dark and desolate, moist, tears from the eyes of
a muffled head. Oh who is that ghost that form
in the dark with tears? What shapeless lump is that
bent crouched there on the sand, streaming tears, sobbing tears,
throws choked with wild cries. Oh storm embodied, rising, careering
(01:27):
with swift steps along the beach, A wild and dismal
night storm and wind, Oh belching and desperate. Oh shade,
so sedate and decorous by day, with calm countenance and
regulated pace, but away at night as you fly, none looking. Oh,
then the unloosened ocean of tears. Tears, tears. That's pretty good,
(01:50):
So listeners probably know I'm a big fan of Walt Whitman,
But it has that that great contrast that's in so
many of his poems, of the kind of beautiful, flowing
expressive like long lines and phrases, but then they're punctuated
by these exclamations, just like shouting a word. Uh. And
I almost quite don't know how to how to render
that in readings. I feel like I should be yelling it,
(02:11):
but that would probably be inappropriate to do into the microphone.
I think you could look for guidance in various grindhouse
movie trailers where they repeat the title of the film times.
You know, zombie, zombie, zombie shockma. You know that kind
of thing, just over and over again, Tears, Tears, tears
coming to a theater near you, No wonder to some
(02:33):
team will be admitted. Well, I guess you know you
get the with the repetition in this poem. You do
get the sense of of something that is coming that
cannot be fully control, something that is outside of yourself.
And that is, of course, that is the vibe they're
trying to relay in those movie trailers that by repeating
the title, they're letting you know that the zombie or
the shakma, or whatever the case may be, it is
(02:54):
something that cannot be contained. It's a little bit out
of control. And that's why are you're coming to the
theater to experience the brain is departing, are you going
to get on before it leaves the station? But anyway,
today's topic again is tears, and the main question that
really got me interested in this subject, though I think
we're going to get more into this question in the
second episode than in today's episode, is what is the
(03:18):
biological origin and thus the biological purpose of emotional crying?
Tears as a result of emotional states. What do emotional
tears actually do? And it's important to specify the question
of emotional tears. Because the purpose of tears and say
lubricating the eyes or and protecting them, washing them in
(03:40):
in various ways. That that's a more obvious thing that
you you can you know, you can tell pretty much
what's going on biologically there. But why is it that
humans have this upwelling of fluid in their eyes that
overflows the eyelids and runs down the face, particularly in
response to abstract emotional states, when the feeling joy or
(04:01):
surprise or sadness or terror. Yeah, yeah, I mean because
we can we can all relate to you know, get
a little dust in your eye, tears well up, and
it's about washing stuff out of the eye. But you
find yourself in these other situations where you know, you're
watching a Star Wars movie with your son or something,
and and the waterworks start coming. Clearly there was nothing
(04:23):
in your eye. You're watching Sam with your son, and
you start crying. Okay, I think we we both might
cry if we watched Shakoma together, but not good tears. Um, yeah,
this is this is gonna be a fascinating topic to
discuss in this episode and an unknown number of subsequent episodes.
We're gonna we're kind of taking the same approach with
(04:44):
this topic that we took with our Mirrors episodes. Well,
we'll just see, we'll just keep going until we feel
like we have finished at least for the time being. Um.
But tears, like mirrors, these are things that that everyone
in the in the world can relate to on some level.
You have tears lubricating your eyes right now. And we
(05:04):
have all had had moments of of emotional um tears,
We've had, We've we've wept, we will weep again. And
then of course our art, our mythology, our religion are
our cultures are full of tears, and and there's not
necessarily a universal understanding of what they are, how they
(05:24):
factor into the divine, how they factor into our rights
and rituals. Uh So it's a fascinating topic to unwind. Now.
A very just quick and handy definition of human tears
that comes from one of the sources I turned to
and probably one that I'll get into more in the
subsequent episode or episodes is Holy Tears Book edited by
Patent and Holly Um and they say that tears are
(05:47):
quote a physiological function in response to intense emotion or
physical pain. But to come back to what we just
said about emotion, I think we have to once more
acknowledge that human being especially have an added emotional dimension
to physical pain. For example, as we've discussed on the
show before, tears are linked not merely to the idea
(06:09):
of painful neural feedback, but also to the wider dimensions
of human suffering. And of course there have been endless
treatments on this, and we'll have many more in human
culture as thinkers, dreamers, and artists contemplate the human condition.
But but one take on all of this that we
see in both Western and Eastern traditions is the idea
that we suffer because we fixate on things and even
(06:32):
living being living beings that are impermanent, and we are
of course creatures of impermanence as well. Uh, you know,
nothing is going to last forever. Everything and to some
degree is ephemeral. Everything to some degree is little more
than a dream. So it's not just that there's pain,
it's the emotional context of the pain, what it means
(06:53):
for things that were and things that could or will be.
Because I think one of the you know, the the
easy to imagine and even remember and to anticipate examples
of human tears are like a kid falls, scrapes up
their knee and then they're crying and and honestly that
that can happen with with adults too. It's not just
a kid's thing. You can suffer an injury. Uh, you
(07:15):
might find yourself shedding some tears. It can be you know,
it can be just an automatic response. But the idea
seems to be that that in the in the human context,
we have this additional stuff as well. You know that
we are thinking we may, let some level, be connecting
two past experiences of say, scraping our knee, the anticipation
(07:35):
of realizing I'm gonna have this annoying, um, you know,
injury and then scab on my knee that sort of thing,
or I am embarrassed by what happened. There are these
other connotations that are involved with the physical uh pain scenario. Well,
in the specific scenario you describe, I couldn't help but
think that one of the things that is most strongly
(07:55):
tied to the tearful response and in response to pain
in or emotional distress, especially in a child, is the
is the separation aspect, Like when a child is separated
from their you know, parent or caregiver, like whoever the
authority figure that would turn to at this moment. Is
that's the thing that seems most powerfully motivating of the tears,
(08:17):
right because often with a kid, like the tears are
there until or or or they can start to subside,
like once the parent gets to them. Yeah, and in
that we get into the the the communication aspects of tears,
which is something that we'll we'll be talking about at
length as well. You know, the idea that we're when
(08:37):
we're weeping like this, it is because someone else needs
to pick up on it and their varying degrees. That
will discuss in that. But yeah, and another thing we're
pointing out, I think is that you know, the obviously
that one can be in a more emotionally raw state
and then you'll find yourself more susceptible to spontaneous tears,
(08:58):
perhaps over something that normally would not generate these tears,
but you already have some other kind of emotional connotation
going on in the background, right, Like you're already stressed
and then you're you're crying because like you can't get
the padlock on the shed open right right, or yeah,
or you miss a particular person, be there somebody who's
just away or has has died, and then there's something,
(09:21):
some sort of emotional media or or even just a
like a household item you encounter and that can be
enough to push you over the edge. So it's not
the idea that you know, just looking at this hammer
made you cry, but perhaps that the memories associated with it,
the emotions associated with it, and to come back to,
you know, some of these ideas that you see in
in both Greek and Buddhist thought, the idea that attachment
(09:44):
is playing a role, that you are still uh, you know,
suffering from attachment to this thing or this person that
perhaps no longer is all right. Well, before we get
into the evolutionary questions, the questions about the purpose of
emotional and only linked tear responses, we should look at
some basic anatomical facts. So tears are a clear liquid
(10:06):
that covers the eye. They're secreted by what's called the
lachrymal gland. And here is an I was always wrong
about this moment. I want to admit I had I had,
you know, like I tear stuff anatomy wrong my entire
life until I was getting ready to do this episode.
I always thought that the lachrymal gland and the tear
(10:28):
duct were the same thing. The tear duct is, of
course in the inside corner of your eye, where the
eye meets the bridge of your nose, and I thought,
I thought this was the same as the lachrymal gland.
I thought, this is where tears came from. And these,
in fact are not the same thing at all. Tears
are secreted by the lachrymal gland via the lachrymal ducts,
(10:48):
and this tear producing apparatus is position actually over the
top of the eye, sort of on the outside of
each eye. So each eye, you think of like go
up from the middle of it over where your eyebrow
and then move a little towards the outside of your head.
That's where your lachrymal glands are. And now that I
think about it, I guess um it would probably make
sense for a gland that produces a fluid that's supposed
(11:12):
to flow over the surface of the eye to be
positioned above the eye instead of below it, just because
you know, gravity would sort of help move the fluid
in the right direction, right. Yeah, It's like putting the
water tower on the on the roof of the building,
that sort of thing. Yeah. I don't know that I
would have known this previously either, had it not been
for the fact that my my son had an issue
(11:34):
with his tear ducks and had to have tubes put
in there. Uh, because before that, he would just like
tears would come out for like either very easily during
an emotional outbursts, but also for no seeming reason at all.
Like I remember one time when he was an infant
and I like moved in and I like, I like
want to kiss him on the forehead, and instead I
(11:56):
kissed him on the eyelid, and it caused tears to
shoot out of his tear duck into my mouth. Oh yeah,
And uh, anyway, it was no ideal. We got it,
got the tubes put in, and he's been fine ever since.
Oh I'm glad to hear that. I was actually reading
that blockage of the tear ducks that prevents proper draining
(12:17):
of the eyes is very common in children. There are
multiple reasons that can happen. Yeah, he did weep at
least a couple of drops of blood from from those
tear ducks, though right after he had the surgery, so
it was he was. That was kind of neat and
again not not painful, but just a normal, right, normal
post surgical situation that they warned us about. They said, look,
(12:40):
there might be some blood that comes out of the tear. Duck,
don't freak out about it. This is not a biblical
event or anything. Normal side effect. Yeah, but it was
knowing it was coming, it was kind of cool. So yeah,
you can probably hear based on what we're just talking about.
The the tear duct that is on the inside corner
of the eye, where the eye meets the bridge of
the nose. This actually has a different function. This is
(13:02):
not where tears come from. This is a drainage system,
or if you prefer, you could think of it as
the sewer of the eye. I don't know that I
like the sound of that, but that that very well.
We do not allow stigmatization of sewers. Sewers are great.
So the way it works is that tears are continually
(13:24):
produced to cover the surface of the eye and they
stay there the you know, when you blink, it helps
spread the spread the tear fluid around the surface of
the eye keeps it well, well moisten and lubricated there
and then Eventually these tears drained down into openings called
punkta that are on the inside corners of your eyelids.
(13:44):
And then from here they drained down into narrow tubes
in a cabin into a cavity called the lachrymal sack,
and again this is on the inside corners of your eyes.
And then finally from there they drained down into a
duct where they empty into your nose. An interesting note
I believe, based on a few things I was reading,
I think this is actually the main reason that your
(14:06):
nose runs when you cry. Um. So, you know, when
you cry, it's often not just fluid coming out of
your eyes running down your cheeks, but also, like you know,
it's suddenly like you have a cold as well. Your
nose might get stopped up or your nose might run.
And it seems that one reason this is happening is
that you've got lots of extra tears flowing into the
nasal cavity via this duct system where they mix with
(14:29):
nasal mucus and they form this mucacy liquid of a
thinner consistency than normal, which sort of drips out your
nose holes and down the back of your throat. It's
it's easy to forget given that we we see it,
we probably consume a lot more like media crying and
movie crying. You don't always have the snot involved during
the movie crying. Sometimes you do, and when when it's there,
(14:51):
I applaud it because I'm like, that's real. There's some
real water works. Yeah. Yeah, the sanitized crying. It's like
how in movies when an attractive actor or they like
get into some big scuffle. You know, they've been like
rolling around in the mud and all that, but then
they come up and then like their hair is still
perfect and their makeup is perfect and they still look
super great. Yeah. Uh. They do the same thing with crying.
(15:12):
There's like a sanitized unreality to crying in movies where
they they still want you to like look cool, so
they're not gonna give you like a red running nose.
They're just gonna have the single tear going down the cheek. Yeah.
And and you know, I have wondered in the past
with with certain actors who are known for this ability
if perhaps sometimes they do have some sort of a
tear duck situation that allows them to like easily produce
(15:34):
a tear without like actively engaging the rest of their
their face. Uh, because yeah, like a full on bawling situation.
Sometimes the snot that you're gonna have snot involved. You're
gonna have like red, puffy faced a situation going on.
And yeah you don't. You don't see that as much
in films, or at least not in you know, the big,
(15:55):
big mainstream films. Well, one thing I was reading about
is that some people have conditions where their eyes are
too dry, like that they don't have enough of the
standard tear fluid um over their eyes. And one way
of dealing with this is a procedure that I think
at least partially blocks the ducks that are draining away
from the eyes normally. And one side effect of this procedure,
(16:17):
if you have to get it to to help moisten
your eyes better, is that with that blockage, now if
you start crying, you don't get a running nose. Interesting, now,
this just brings to mind all sorts of of possible
nightmare scenarios where an actor is getting a bunch of
like nasal surgery done purely so that they can cry
(16:39):
on command without experiencing a running nose or or blushing
of the face. Oscar Baits scenes without the snot that
would would make them look unattractive. But I think it's
it's it's interesting that we're you know, we're talking about
the like the the physical complexity of tear production and
how integrated it is with the you know, the rest
(17:00):
the plumbing of our face, because that does match up
with a lot of what we just said about the
human emotional uh context, you know, how how our emotions
are so wrapped up in all these other processes as well.
So it feels like it feels right that these two
things should both be so indebted. You know who we are,
(17:23):
thank you, Thank now. Researchers have noted basically three broad
categories of tears that are present in humans. There are
three different ways you can make tears. The first is
what we've already been talking about, which is basal tears.
Basil tears are not a response to anything in particular. Instead,
basal tears are what is always present, is always being
(17:47):
produced by the lachrymal gland, always coating the surface of
the eye and then draining away gradually through the tear
ducts on the inner eye. And one reason we blink
actually is to help keep this ever present layer of
basal tears evenly spread out over the eyeballs. An interesting
fact I discovered about basal tears They are not a
(18:07):
homogeneous liquid. They instead consist of a number of distinct
components that tend to settle into layers. When coding the
eye and so going from the inside out, I want
mentioned the three different layers. So the first layer, the
closest your eye, is the mucous layer, and this layer
tears contain this This mucus that is I believe secreted
(18:29):
by epithelial cells within the eye itself rather than from
the lachrymal gland um, and this helps the tier film
stick to the surface of the eye. This would be
similar to the way that a lot of the tissues
inside the body have a layer of epithelial cells that
serve to secrete a mucus that helps like a lubricate
or somehow protect the inner surface of or the outer
(18:52):
surface of the organ. Then after that there is the
watery layer or the aqueous layer, and this is the
bulk of the salty ear liquid. This is secreted by
the lacrimal glands. But then on top of that there
is a lipid layer or oily layer, the oily coat
on top of the tears, So the sea of your
tears on your eye is topped by an oil slick,
(19:14):
and this apparently helps protect the liquid layer. It slows
down evaporation and so forth. So when you consider your tears,
know that they do in fact contain multitudes. However, all
of this is present even when we're not thinking about tears,
because they're not overflowing the eyelids just in the normal
cycle of of blinking and lubrication and so forth. That's
(19:37):
all just in the basal tears. What about these other
two kinds of tear responses present in humans. Well, the
next kind that you would want to look at is
known as reflex tears, or maybe irritant tears, and this
is when the eye overflows with tears in response to
a physical condition. So if you get sand in your eye,
(19:58):
or if you punish yourself with volatile sulfur compounds from
chopping onions with a dull knife. This this is the
eye detecting irritation of some kind and going into self
cleaning mode, producing lots of tears to protect itself and
to wash away potential contaminants. But then finally you get
into the most enigmatic category, which is emotional tears. Uh.
(20:20):
And and this is that this is the really strange
and interesting one, the welling of tears in the eyes
and the absence of a physical cause in the eye itself,
but owing instead to an abstract emotional state. And while
the other two categories of tears can be found in
other animal responses, it's the emotional tears that apparently, at
least according to many researchers, are pretty much unique to
(20:44):
Homo sapiens. I think it's pretty widely agreed that Homo
sapiens are the only extant animal that the cries emotionally,
that produces emotional tears, and certainly on a regular basis.
So this brings us back to this interesting question. Why
do we shed tears when we're overcome with joy or
sadness or even surprise. These things that are originally there
(21:06):
to lubricate and protect the eye and then maybe to
sort of overflow and wash out irritants in the case
of some kind of physical distress. Why would they show
up when you see a dog getting reunited with its owner.
Oh yeah, yeah, I mean I think the animal videos
certainly get to a lot of us, or or cheetah
(21:27):
and dog who are friends. It's another one. Any any
baby animal, Yeah, why why do we need It's not
like those things are are going going to admit particles
that could irritate our eyes and then our eyes are like,
oh no, here comes a cute animal. That would be
great if there was like an emotional you know. So
you just know that whenever there's a cute animal, it's
(21:49):
also emitting like oniony sulfur compounds that are gonna get
in your eyes, and so it's it's protective like that.
But no, I mean, we don't know of anything of
that kind. At least there's nothing obvious of that kind.
So you've got to look to other explanations. Though actually
there is one explanation that's that's almost certainly a bad
explanation for the evolutionary origins of tears, But I'm going
(22:10):
to mention it later in this episode just because it's, uh,
it's it's kind of funny to consider, even though it's
almost definitely wrong, but it sort of follows this method anyway.
We'll come back to that. So it seems a major
clue in looking at at the the evolutionary purpose of
tears to observe that emotional tears seem to be pretty
much unique to human beings. The Roman poet Juvenile said, uh,
(22:34):
nature in giving tears to man confessed that he had
a tender heart. This is our noblest quality. So, you know,
like the juveniles observing something unique about human beings being
able to cry, uh, noble tears, Tears that have a
meaning rather than just being like washing out irritation from
the eye sockets. This is of course something that that
(22:55):
comes up quite a bit. And Holy Tears that book
I referenced earlier from Patton and Holly, they're they're the editors,
but it contains work by other authors, other bits of
scholarship about tears and how they factor into rights and religion.
But yeah, we we tend to look at the human
condition and we say, okay, humans are capable of these
complex emotional states. They're they're capable of feeling sorrow and empathy. Also,
(23:19):
we we we shed tears in many of these emotional states.
And then we just we kind of assume that these
two things are one, that that that we we have tears,
therefore we have emotional states. We have emotional states, Therefore
we have tears and uh. And we see that bleed
over into our conception of various supernatural entities as well
(23:41):
all of our our human like creatures and beings and
myth and religion. They're all these stories of of course,
not only mythological heroes and demi gods shedding tears, but
God um itself shedding tears. Also various monsters and creatures
shedding tears tears uh and uh. And so that it's
(24:03):
interesting to take all of that and then you look
to the animal world, and I think in doing so,
we do have to stress that that ultimately, when we're
even if we're saying an animal does not shed tears,
or another like primate for instance, does not shed emotional tears,
it does not mean that they don't have emotional states,
um and and uh. And in a way that that
(24:27):
this is kind of an overstatement of the obvious, but
I think it's it's so important to drive home because
the idea of of human emotions and tears are so
closely linked, like they're just inseparable. Yeah, yeah, I see
what you're saying there, and I think that's a very
good point. You a person could naively assume, Oh well,
because if it's the case that only humans really shed
(24:48):
tears in response to emotions, that must mean humans have
like better, more sophisticated emotions than animals do, or or
more powerful emotions than animals do. You can't necessary really
conclude that, I mean one doesn't follow from the other. Yeah,
so you know, I think it. Ultimately, we can all
engage our creativity. We can imagine alien species, you know,
(25:09):
in a Star Wars or Star Trek kind of scenario.
We can easily imagine beings that have complex emotional states
at least on par with human beings that don't shed
tears like we do. Maybe they do something else that
that communicates uh, their emotional state to others. Maybe it's
a change in coloration, maybe they admit a certain odor.
(25:30):
Maybe it's some sort of a light based scenario, or
I don't know. Um if we're going to try and
come up with something that is on par with and
maybe ultimately as mysterious as why why is when are
my eyeballs producing extra liquid? Maybe it's like extra sweating.
You know, you're you're at a funeral, So what do
you do? You sweat? You sweat with everybody else? Um,
(25:52):
or you salivate a lot. That's kind of thing emotional flatulence.
I mean, there could be all kinds of like the
body could release all kind ends of substances in response
to powerful emotions. Right, But this is the adaptation that
our ancient ancestors, uh, somehow acquired, and the question would
be how did they acquire it and why? Now in
in Holy Tears, there's a there's a wonderful little line.
(26:15):
There's so many great lines in this, but I want
to read this quick one before I move forward. Quote,
among the very earliest expressions of distress in the infants range,
tears remain a profound existential signifier at all stages of
human life, particularly in the face of fear, loss, or despair.
And I think that's true. I think that that's a
that's a great statement. But I started looking around a
(26:37):
little bit, and uh, I realized, Oh, newborn babies don't
actually shed emotional tears. And this is I have to admit,
I don't have a lot of experience with the very
young children. So maybe I just haven't been around enough
like brand new babies, like less than a month old
sort of thing. But the uh, the fact seems to
(26:58):
be that the eyes of an infant remains a pretty
dry for the first two weeks of life. Now there, Uh,
their tear glands are functional, but they don't make enough
of the stuff for it to be seen as as
as obvious tears in the eye. So they might they
might be bawling, for example, and you're not going to see,
you know, the water works flowing. After two weeks, however,
(27:21):
those glands are gonna boost production, and most children, according
to Karen gil m d writing for Healthline, create full
tears between one and three months into their lives. That
is interesting because it makes you think about what are
the components of crying Again, this is something that will
probably become more significant when we talk about a lot
of some of the major theories in the next episode.
(27:42):
But crying entails multiple behavioral signals, right, So an infant
can cry and it would do a thing that everybody
would recognize as crying, and you would say, yeah, that's crying,
even without shedding liquid tears running down its face. I mean,
it will make a vocalization and you see like contortions
of the face in a certain way, and uh, kind
(28:04):
of like screaming or bawling, and everybody knows that's crying
even though the tears are not present. And yet once
you reach a certain age, the tears are present, and
we start to think of tears as an important part
of crying, especially adult crying. Yeah. Yeah, So on one level,
when we're looking elsewhere in the animal world, we have
to be very specific about what we're talking about with crying.
(28:26):
And this was pointed out by professor in comparative biology
Kim A. Bard Uh in a bit she wrote for
Scientific America, pointing out that crying has been used to
describe just the vocalization of various primates. So if you're
just very generally saying, we'll do other primates cry, well, yes,
other primates do cry out, They create vocalizations, and and
(28:47):
obviously you know these vocalizations are about communicating something, uh
to other creatures and or other primates. But if we're
indeed going to focus in on tears and quote fearful sobbing,
then humans do seem to be alone. It doesn't mean, again,
that we're the only primates capable of feelings, say sorrow
(29:07):
or other complex emotions. We don't really have a firm
answer on that count yet, but there I think there's
some some strong arguments to be made, but we're the
only ones who shed tears of sorrow right now. I
think a lot of you probably your brains went to
the same place as mind did at this point, and
I my I thought, well, what about Neanderthals. Did these
(29:28):
intelligent relatives of humans that went extinct about forty tho
years ago? Did they shed tears like we do? Right?
I mean, I guess this would be a question and
part of how far back the emotional tear adaptation goes
like did our you know, the common ancestor of Neanderthals
and Homo sapiens have this tear response that it would
(29:48):
would give to both of them or or is it
a more unique property of Homo sapiens specifically? Yeah, And
then also I think it's it's it's worth thinking about
uh and exploring to to to a limited extent because
you think about, well, what can what what what could
Neanderthals do? Like what do we know that they had
(30:09):
that human that modern humans also had? And have you know,
they had access to various technologies, they created art, and
depending on on how you look at the artifacts, they
may have engaged in funeral rights as well, so, on
one hand, it seems like a lot of the things
that we attribute to the human condition and human you know,
(30:31):
civilization even and the emotional states associated with them, we
can look to the Neanderthal world and say, well, they
had these things. So perhaps you know, so it seems
like they had emotional states like we did. But does
that mean that they could produce tears as well? Emotional
tears not necessarily a given? Yeah, yeah, so uh So
(30:52):
I started looking into this a little bit, and it's
it's interesting because the topic was somewhat muddled by some
scholarship in the mid nineties. There was I believe this
was a nineteen nineties nineties six article that came out
in p N a s uh significance of some previously
unrecognized uh apo morphies in the nasal region of Homo
(31:17):
neandertal insis. And this was from a pair of researchers
Shorts and Tattersall Okay, so uh to clarify in that title,
apo morphies would refer to unique traits, unique physical traits
of a species, right, and so this particular paper, uh,
basically what it was doing is looking at various remains
(31:40):
all of Deandertals and claiming that that there were there
were aspects of their nasal uh makeup that seemed to
be different from humans and all of their primates. And
there were so and and one of these was the
idea that peer ducts seemed to be absent. And this
caused quite a stir at the time time because oh, well,
(32:01):
this is this was this On one hand, this would
be amazing if we found this out, like what does
this mean that Neanderthals seemed to be distinct from all
other primates? Uh? And then it ended up being kind
of hijacked to a certain extent I've read by creationists
who wanted to put the spin on it. Oh, this
means that Neanderdal's they couldn't cry. Humans can cry. We're
(32:23):
the king of crying. We're the we're the only children
of God. God can cry. We can cry apes. Neanderthal's
no crying for you guys. We're the best, which the
divine spark exists only in crying. Brain Yeah, which kind
of goes back to the juvenile quote from earlier, right
like this is this is what humans do, so nothing
(32:45):
else does it and so uh that's you know, which
makes us the noblest of all is right, right. But
the curious thing about this is that it's such a
misread on the paper because, for one thing, the original
researchers here, they they were trying to make that point.
If anything, they were making the opposite point. Neanderthals were
something special, uh not human humans you know, have have
(33:07):
pretty much all the other things in common with the
other primates. Nasal features. They were saying, Oh, the nasal
features of Neanderthals. They this looks distinct. These guys are special.
So if you were going to take some sort of
religious message out of that, it seems like you might
want to say, well, then the Neanderthals were the true
children of God because God decided to give them special
nasal cavities. I don't know, But at any rate, this
(33:31):
particular paper, in this particular study, Uh, it was a
big controversial at the time. I've read and subsequently other
researchers argue that the findings were based on and this
is from a N. P. And S published rebuttal Uh,
it was based on quote reliance on specimens with damaged, incomplete,
(33:52):
or in some cases entirely absent relevant anatomy. So what
they were inferring about the supposed lack of tear ducts
in in the Neanderthals could have actually not been based
on what was something not something universal to Neandertal anatomy,
but just based on problems with the specific like skeletal
remains they were looking at, right, And you know, this
(34:13):
is just this is we see this in plenty of
other studies as well. I mean, this is just kind
of how science works. Sometimes there's something missing, it seems
seems like it might be something. Uh, paper is published
about it, and then subsequently there's kind of a course
correction on it. But I think it does. I've read
that it's still kind of remains out there. You'll still
see this brought up, particularly by some some creationist websites
(34:35):
that will try and use it to prop up this
idea that that human beings are are distinct from other
primates and therefore are not an evolved species or something
to that effect. So to be clear, Neanderthals they had
tear ducks like other primates. But the question that is
still outstanding, I guess would be did they or would
(34:55):
they have been capable of shedding emotional tears like human
like modern woman's do, and that is just that's something
I don't think we have an answer too. I'm not
sure of what we could ever have an answer to
that unless we had a time machine. Though. I guess
perhaps it's conceivable that something could be worked out with genetics.
But maybe, I mean that seems like something, Yeah, a
(35:17):
genetic marker could be possible that gives a predisposition to
a certain kind of behavior. But but yeah, that's difficult
because like emotional weeping is something that may not leave
any kind of physical trace at all that you could detect.
I mean, might it's something that's just a behavior that
may or may not have recognizable genetic markers that point
(35:37):
to it. Yeah, I guess for me, I'm I'm aloathe
to take emotional tears away from Neanderthals just because for
no other reason, it's because we have again, this is
such a strong link between tears and emotional states. Like
I don't want to just assume that Neandertals did not
have emotional states. You know what I'm saying is it
just seems because of that that bad into is and
(36:00):
we were talking about earlier. Yeah, yeah, and it seems
kind of tacky considering the rise of modern humans. Uh,
you know, may have would have played some role in
the extinction of Neanderthals, though the exact role is a
matter of debate. You know, could could just be a
matter of you see that the argument's range from out
competing them resources to like actually hunting them down and
(36:24):
killing them that sort of thing. But whatever the truth there.
I mean, as we talked about earlier, the presence or
absence of weeping as a response to emotion is not
indicative of whether or not there is underlying emotion or
the or the properties of that emotion. Now, this whole
(36:47):
discussion about ancient, ancient humans and Neanderthals has gotten me
thinking about one answer that's been given to the question
of the evolutionary origins of of tearful sobbing. And I'm
citing this because it's it's interesting and kind of funny,
not because it is a good explanation. I think this
(37:07):
is almost definitely wrong. But I came across this in
a book I'll probably refer to again and in the
next episode. This is a book by a Dutch psychologist
named ad Vinger Hoots called Why Only Humans Weep? Unraveling
the Mysteries of Tears from Oxford University Press and Vinger
Hoots is best I can tell. Seems to be one
(37:29):
of the leading experts in the world on the the
origins of crying. He's looked into this question a lot.
He's got a whole book about it, so he will
definitely come up again in the next episode. But anyway,
so he's he's running through a list of all the
different explanations people have given for for the origin of
emotional weeping. And one of these is a hypothesis that
(37:52):
was advanced by a neuroscientist and uh an expert in
emotions named Paul McLean. And so here I want to
quote from from Fingerhood summary quote. He argued that our
emotional tears originated about one point four million years ago,
when the use of fire became more common and our
ancestors burned the corpses of their beloved family and tribe members.
(38:16):
According to McLean and We're published in it was the
smoke from these fires that might initially have generated tear
producing reflexes. Subsequently, the production of tears became a conditioned
reflex due to the association of fire and ceremonies with
emotional events. Now on one level. I love this explanation because,
(38:38):
like it really works on kind of a mythological level.
This would be a great like story to tell, is
when they first started burning the smoke it got in
their eyes. You know, it almost has that sort of
folk tale quality to it. I think this is a
really bad explanation in terms of scientific or evolutionary reasoning, because,
for one thing, a conditioned response learned by our ancient
(38:59):
ancests is having to do with funerary practices. There's really
no explanation of how a conditioned response like that, a
learned response could turn into a genetically determined anatomical response
because like, you know, babies don't need to learn to
shed emotional tears from adults it. You know, clearly emotional
(39:19):
tears are something that just kind of happens naturally with humans.
It doesn't need to be learned from experiencing fires at
funerals or anything like that. Yeah, they've they've mastered it
pretty early on. It's just we we learned from them, really, right,
So yeah, it's clear it's like it's a genetically determined
behavior at this point. It is in our bodies. It's
not something that you have to pick up from culture really, though,
(39:41):
of course there are lots of cultural variations and how
exactly emotional weeping comes through. It's it's clear that there's
a there's an underlying baseline that's in our bodies and
in our DNA. Yeah. The other thing Fingerhood's points out
as a real reason to think this is not a
good explanation for the biologic origins or purpose of crying
(40:02):
is that it's hard to see how tears here would
have any additional survival value. So, right, if you're imagining
when humans they started, they started using fires and used
fires in their funeral rights um and thus came to
associate feelings of sadness and loss with irritation of the eyes,
and this made them weep, and you would have to
(40:24):
imagine that like the people who wept the most. I guess,
as you know, who got the most smoke in their eyes,
or got the or got the most eye irritation and
wept to the most in response to it would have
some kind of uh, some kind of additional survival or
reproduction as opposed to people who didn't, whose eyes didn't
(40:44):
well up a lot at at funerals where smoke was
getting in their faces, it just doesn't seem very plausible.
You can't really imagine scenarios where that leads to having
additional kids that survived further into the future. I mean,
unless we lived in a world where the the old
saying smoke follows beauty is actually true, and then you
(41:04):
might have a situation where you're like, oh, look at
Thag's eyes. He's a mess totally. He's been getting all
the campfire smoke, and he is the most beautiful, He
is the most desired made Again, it's very fun, like
the level of a kind of myth or folk tale.
But I think as a scientific hypothesis, this one just
doesn't really work. But I do think this is a
good illustration of how people are kind of scrambling about
(41:26):
for explanations of in recognizable periods of human history, Like
if humans are the only animals that produce emotional tears,
you see people wanting to find some very very characteristically
human cause of this adaptation, right, which would make people
kind of want to reach to early the examples of culture,
(41:48):
like human culture as a as a cause for it.
Though I think that's not necessarily the right place to look.
Um one more very unlikely explanation I wanted to visit
before we wrap up today. Apparently some people have used
the aquatic ap hypothesis uh to explain the origins of
emotional tears. Now, if you're interested in our our take
(42:11):
on aquatic ape, we several years back we did an
episode on this. The the aquatic ape hypothesis was originally
put forward by a biologist named Alistair Hardy, has since
been championed by scholar named Elane morgan Um. And essentially,
the idea is that a lot of the traits that
(42:33):
are unique to Homo sapiens are evolved because our ancestors
were semi aquatic. Uh. So, like they spent a lot
of time in the water, maybe fishing around for mollusks
and swimming and things like that. And this is used
to explain the relative hairlessness of humans that was for
aerodynamics in the water upright, walking was comes from waiting
(42:56):
around in the water, uh and so forth. Now, as
we concluded in the previous episode, I think that the
aquatic ape hypothesis is really really unlikely to be true
for a number of reasons. But one of the main
ones is that you would have to say, okay, well,
if humans lost all of these traits like walking around
(43:16):
on all fours and and having very hairy bodies in
order to be in the water. How come when they
supposedly came out of the water they retained all of
those adaptations to the water. You would have to come
up with ways of saying, well, uh, it turned out
those adaptations proved useful on the land as well for
some reason. But then, but then if you have that,
(43:37):
why couldn't they just have been adaptive on the land
to begin with. Plus, there's no direct evidence for the
aquatic ape scenario, so this just seems like, um, you know,
it's kind of it's fun to imagine, but it really
has no direct evidence going for it. Yeah, it's it's
it's a fun topic to to read about and to discuss,
even because it it's it's kind of like imagining a
(43:58):
scenario where you need to get across the wood. It's
from point A to point B, and uh. You know,
someone might ask, well, why can't we take this path? Uh? Well,
sometimes taking that path, you can realize, oh, this is
the harder path. After all. It seems like it's shorter,
but you have to cross a number of streams to
get there. You have to you have to do a
lot more work, even though at the on the outset
(44:18):
it seems like it is the most straightforward path. Uh,
it's not. But then and then the other thing about
it too, is that the aquatic aphypothesis, why you know,
who will incorrect. If you learn about it, you do
learn about other other scientific topics that are accurate. I mean,
you are learning a little bit about about the evolution
(44:39):
of aquatic mammals and so forth. It just doesn't have
anything to do directly with what our bodies have done. Like,
it's still beyond amazing to to look at a whale
and realize that this was once a kind of shaggy
wolf type creature living living along the shore and catching
fish in the water. Uh, and that eventually it would
(45:02):
it would become this, you know, behemoth, this leviathan. Uh,
you know the ocean. That's that's amazing stuff. Oh yeah,
it is. Uh. And and you know, it's it's a
very it's very seductive because it's cool to imagine humans
becoming like semi aquatic creatures and and adapting this way.
I mean, I think the aquatic a hypothesis is uh,
(45:25):
despite not having a lot of explanatory power and no
direct evidence for it. I think it's attractive to people
on the same basis that, for example, a lot of
like conspiracy theories are which is that this is something
I know I've said on the show before, but I
think a lot of times people underestimate how much people
believe certain things because it's fun to believe them, sort
(45:51):
of like entertainment or interest. First theory of epistemology that
people are attracted to certain explanations of the real world,
not really because of anything about how well they explain things,
but because it's pleasurable to believe certain things about the world,
Like entertaining certain theories like the aquatic ape theory is
(46:12):
kind of mentally exciting. Yeah, yeah, absolutely. I mean these
various sort of fringe hypotheses, you know, some of which
that we've explored on the show before. They can they
can almost fill the space of religion in in the mind,
you know, they can be this this thing that I
think ultimately that's perhaps the healthier way to to correspond
(46:33):
with some of them, to say, uh, you know, for instance,
I really like the aquatic ap theory. Do I think
it's real, No, but I think it is an interesting
topic to look at, and perhaps you can even expand
on it and imagine fictional worlds in which this is
the path that human evolution took. I don't know, totally
totally yeah, um, so, anyway that the the the aquatic
(46:54):
ape hypothesis encompasses also, among the many things it purports
to explain, it has been alleged that it also explains
uniquely human tear traits. Um. But I guess maybe we
need to wrap up the first part here, But when
we come back in the next episode, we can talk
about some of the major theories leading theories today about
(47:15):
why humans shed tears as an emotional response. And there's
also something I want to look at in the next
episode which is very interesting. What is the origin of
the concept of crocodile tears? There's a lot of fun
in this. Uh, just one little teaser on that. Apparently
some ancient and medieval sources alleged that as a crocodile
(47:35):
was eating an animal, or maybe even eating a human,
it would shed tears in order to tender rize the
head of the animal it was eating. I don't know
how that allegedly works, but oh wow, all right, well
that that sounds like it'll be fun more on this topic,
but with a little uh medieval uh medievalism thrown in
(47:56):
there as well. So yeah, I'm looking forward to it.
In meantime, if you would like to listen to other
episodes of Stuff to Blow Your Mind, you'll find them
all in the all the episodes and the Stuff to
Blow Your Mind podcast feed you'll find out wherever you
get your podcasts. We have core episodes on Tuesdays and
Thursdays and rerun on the weekend, Artifact episode on Wednesday,
(48:16):
listener mail on Monday, and on Friday's we do a
Weird House Cinema episode. That's our time to set aside
most of the science and just talk about a weird movie.
Huge things. As always to our excellent audio producer Seth
Nicholas Johnson. If you would love to get in touch
with us with feedback on this episode or any other,
to suggest a topic for the future, or just to
say hello, you can email us at contact at Stuff
to Blow your Mind. Dr. Stuff to Blow Your Mind
(48:45):
is production of I Heart Radio. For more podcasts for
my Heart Radio, visit the iHeart Radio app, Apple Podcasts,
or wherever you're listening to your favorite shows. By the
present joint four point four PC first FO
My Welcome to Stuff to Blow Your Mind production of
My Heart Radio. Hey, welcome to Stuff to Blow Your Mind.
My name is Robert Lamb and I'm Joe McCormick. And
today we're going to be kicking off the first episode
(00:21):
in a series about the subject of tears. This is
something I've gotten really interested in in the last couple
of weeks, Questions about the biological origins of crying and
things like that. But before we get started to set
the mood, I wanted to to read a poem by
Walt Whitman that's all about tears. In fact, it's so
much about tears. It just has the word tears followed
(00:44):
by an exclamation point, like at least six or seven times.
All Right, you ready for Grandpa Wald, Let's do it,
hit it? Okay. The poem goes tears, Tears, Tears in
the night in solitude, Tears on the white shore, dripping, dripping,
sucked in by the sand. Tears not a star shining,
(01:04):
all dark and desolate, moist, tears from the eyes of
a muffled head. Oh who is that ghost that form
in the dark with tears? What shapeless lump is that
bent crouched there on the sand, streaming tears, sobbing tears,
throws choked with wild cries. Oh storm embodied, rising, careering
(01:27):
with swift steps along the beach, A wild and dismal
night storm and wind, Oh belching and desperate. Oh shade,
so sedate and decorous by day, with calm countenance and
regulated pace, but away at night as you fly, none looking. Oh,
then the unloosened ocean of tears. Tears, tears. That's pretty good,
(01:50):
So listeners probably know I'm a big fan of Walt Whitman,
But it has that that great contrast that's in so
many of his poems, of the kind of beautiful, flowing
expressive like long lines and phrases, but then they're punctuated
by these exclamations, just like shouting a word. Uh. And
I almost quite don't know how to how to render
that in readings. I feel like I should be yelling it,
(02:11):
but that would probably be inappropriate to do into the microphone.
I think you could look for guidance in various grindhouse
movie trailers where they repeat the title of the film times.
You know, zombie, zombie, zombie shockma. You know that kind
of thing, just over and over again, Tears, Tears, tears
coming to a theater near you, No wonder to some
(02:33):
team will be admitted. Well, I guess you know you
get the with the repetition in this poem. You do
get the sense of of something that is coming that
cannot be fully control, something that is outside of yourself.
And that is, of course, that is the vibe they're
trying to relay in those movie trailers that by repeating
the title, they're letting you know that the zombie or
the shakma, or whatever the case may be, it is
(02:54):
something that cannot be contained. It's a little bit out
of control. And that's why are you're coming to the
theater to experience the brain is departing, are you going
to get on before it leaves the station? But anyway,
today's topic again is tears, and the main question that
really got me interested in this subject, though I think
we're going to get more into this question in the
second episode than in today's episode, is what is the
(03:18):
biological origin and thus the biological purpose of emotional crying?
Tears as a result of emotional states. What do emotional
tears actually do? And it's important to specify the question
of emotional tears. Because the purpose of tears and say
lubricating the eyes or and protecting them, washing them in
(03:40):
in various ways. That that's a more obvious thing that
you you can you know, you can tell pretty much
what's going on biologically there. But why is it that
humans have this upwelling of fluid in their eyes that
overflows the eyelids and runs down the face, particularly in
response to abstract emotional states, when the feeling joy or
(04:01):
surprise or sadness or terror. Yeah, yeah, I mean because
we can we can all relate to you know, get
a little dust in your eye, tears well up, and
it's about washing stuff out of the eye. But you
find yourself in these other situations where you know, you're
watching a Star Wars movie with your son or something,
and and the waterworks start coming. Clearly there was nothing
(04:23):
in your eye. You're watching Sam with your son, and
you start crying. Okay, I think we we both might
cry if we watched Shakoma together, but not good tears. Um, yeah,
this is this is gonna be a fascinating topic to
discuss in this episode and an unknown number of subsequent episodes.
We're gonna we're kind of taking the same approach with
(04:44):
this topic that we took with our Mirrors episodes. Well,
we'll just see, we'll just keep going until we feel
like we have finished at least for the time being. Um.
But tears, like mirrors, these are things that that everyone
in the in the world can relate to on some level.
You have tears lubricating your eyes right now. And we
(05:04):
have all had had moments of of emotional um tears,
We've had, We've we've wept, we will weep again. And
then of course our art, our mythology, our religion are
our cultures are full of tears, and and there's not
necessarily a universal understanding of what they are, how they
(05:24):
factor into the divine, how they factor into our rights
and rituals. Uh So it's a fascinating topic to unwind. Now.
A very just quick and handy definition of human tears
that comes from one of the sources I turned to
and probably one that I'll get into more in the
subsequent episode or episodes is Holy Tears Book edited by
Patent and Holly Um and they say that tears are
(05:47):
quote a physiological function in response to intense emotion or
physical pain. But to come back to what we just
said about emotion, I think we have to once more
acknowledge that human being especially have an added emotional dimension
to physical pain. For example, as we've discussed on the
show before, tears are linked not merely to the idea
(06:09):
of painful neural feedback, but also to the wider dimensions
of human suffering. And of course there have been endless
treatments on this, and we'll have many more in human
culture as thinkers, dreamers, and artists contemplate the human condition.
But but one take on all of this that we
see in both Western and Eastern traditions is the idea
that we suffer because we fixate on things and even
(06:32):
living being living beings that are impermanent, and we are
of course creatures of impermanence as well. Uh, you know,
nothing is going to last forever. Everything and to some
degree is ephemeral. Everything to some degree is little more
than a dream. So it's not just that there's pain,
it's the emotional context of the pain, what it means
(06:53):
for things that were and things that could or will be.
Because I think one of the you know, the the
easy to imagine and even remember and to anticipate examples
of human tears are like a kid falls, scrapes up
their knee and then they're crying and and honestly that
that can happen with with adults too. It's not just
a kid's thing. You can suffer an injury. Uh, you
(07:15):
might find yourself shedding some tears. It can be you know,
it can be just an automatic response. But the idea
seems to be that that in the in the human context,
we have this additional stuff as well. You know that
we are thinking we may, let some level, be connecting
two past experiences of say, scraping our knee, the anticipation
(07:35):
of realizing I'm gonna have this annoying, um, you know,
injury and then scab on my knee that sort of thing,
or I am embarrassed by what happened. There are these
other connotations that are involved with the physical uh pain scenario. Well,
in the specific scenario you describe, I couldn't help but
think that one of the things that is most strongly
(07:55):
tied to the tearful response and in response to pain
in or emotional distress, especially in a child, is the
is the separation aspect, Like when a child is separated
from their you know, parent or caregiver, like whoever the
authority figure that would turn to at this moment. Is
that's the thing that seems most powerfully motivating of the tears,
(08:17):
right because often with a kid, like the tears are
there until or or or they can start to subside,
like once the parent gets to them. Yeah, and in
that we get into the the the communication aspects of tears,
which is something that we'll we'll be talking about at
length as well. You know, the idea that we're when
(08:37):
we're weeping like this, it is because someone else needs
to pick up on it and their varying degrees. That
will discuss in that. But yeah, and another thing we're
pointing out, I think is that you know, the obviously
that one can be in a more emotionally raw state
and then you'll find yourself more susceptible to spontaneous tears,
(08:58):
perhaps over something that normally would not generate these tears,
but you already have some other kind of emotional connotation
going on in the background, right, Like you're already stressed
and then you're you're crying because like you can't get
the padlock on the shed open right right, or yeah,
or you miss a particular person, be there somebody who's
just away or has has died, and then there's something,
(09:21):
some sort of emotional media or or even just a
like a household item you encounter and that can be
enough to push you over the edge. So it's not
the idea that you know, just looking at this hammer
made you cry, but perhaps that the memories associated with it,
the emotions associated with it, and to come back to,
you know, some of these ideas that you see in
in both Greek and Buddhist thought, the idea that attachment
(09:44):
is playing a role, that you are still uh, you know,
suffering from attachment to this thing or this person that
perhaps no longer is all right. Well, before we get
into the evolutionary questions, the questions about the purpose of
emotional and only linked tear responses, we should look at
some basic anatomical facts. So tears are a clear liquid
(10:06):
that covers the eye. They're secreted by what's called the
lachrymal gland. And here is an I was always wrong
about this moment. I want to admit I had I had,
you know, like I tear stuff anatomy wrong my entire
life until I was getting ready to do this episode.
I always thought that the lachrymal gland and the tear
(10:28):
duct were the same thing. The tear duct is, of
course in the inside corner of your eye, where the
eye meets the bridge of your nose, and I thought,
I thought this was the same as the lachrymal gland.
I thought, this is where tears came from. And these,
in fact are not the same thing at all. Tears
are secreted by the lachrymal gland via the lachrymal ducts,
(10:48):
and this tear producing apparatus is position actually over the
top of the eye, sort of on the outside of
each eye. So each eye, you think of like go
up from the middle of it over where your eyebrow
and then move a little towards the outside of your head.
That's where your lachrymal glands are. And now that I
think about it, I guess um it would probably make
sense for a gland that produces a fluid that's supposed
(11:12):
to flow over the surface of the eye to be
positioned above the eye instead of below it, just because
you know, gravity would sort of help move the fluid
in the right direction, right. Yeah, It's like putting the
water tower on the on the roof of the building,
that sort of thing. Yeah. I don't know that I
would have known this previously either, had it not been
for the fact that my my son had an issue
(11:34):
with his tear ducks and had to have tubes put
in there. Uh, because before that, he would just like
tears would come out for like either very easily during
an emotional outbursts, but also for no seeming reason at all.
Like I remember one time when he was an infant
and I like moved in and I like, I like
want to kiss him on the forehead, and instead I
(11:56):
kissed him on the eyelid, and it caused tears to
shoot out of his tear duck into my mouth. Oh yeah,
And uh, anyway, it was no ideal. We got it,
got the tubes put in, and he's been fine ever since.
Oh I'm glad to hear that. I was actually reading
that blockage of the tear ducks that prevents proper draining
(12:17):
of the eyes is very common in children. There are
multiple reasons that can happen. Yeah, he did weep at
least a couple of drops of blood from from those
tear ducks, though right after he had the surgery, so
it was he was. That was kind of neat and
again not not painful, but just a normal, right, normal
post surgical situation that they warned us about. They said, look,
(12:40):
there might be some blood that comes out of the tear. Duck,
don't freak out about it. This is not a biblical
event or anything. Normal side effect. Yeah, but it was
knowing it was coming, it was kind of cool. So yeah,
you can probably hear based on what we're just talking about.
The the tear duct that is on the inside corner
of the eye, where the eye meets the bridge of
the nose. This actually has a different function. This is
(13:02):
not where tears come from. This is a drainage system,
or if you prefer, you could think of it as
the sewer of the eye. I don't know that I
like the sound of that, but that that very well.
We do not allow stigmatization of sewers. Sewers are great.
So the way it works is that tears are continually
(13:24):
produced to cover the surface of the eye and they
stay there the you know, when you blink, it helps
spread the spread the tear fluid around the surface of
the eye keeps it well, well moisten and lubricated there
and then Eventually these tears drained down into openings called
punkta that are on the inside corners of your eyelids.
(13:44):
And then from here they drained down into narrow tubes
in a cabin into a cavity called the lachrymal sack,
and again this is on the inside corners of your eyes.
And then finally from there they drained down into a
duct where they empty into your nose. An interesting note
I believe, based on a few things I was reading,
I think this is actually the main reason that your
(14:06):
nose runs when you cry. Um. So, you know, when
you cry, it's often not just fluid coming out of
your eyes running down your cheeks, but also, like you know,
it's suddenly like you have a cold as well. Your
nose might get stopped up or your nose might run.
And it seems that one reason this is happening is
that you've got lots of extra tears flowing into the
nasal cavity via this duct system where they mix with
(14:29):
nasal mucus and they form this mucacy liquid of a
thinner consistency than normal, which sort of drips out your
nose holes and down the back of your throat. It's
it's easy to forget given that we we see it,
we probably consume a lot more like media crying and
movie crying. You don't always have the snot involved during
the movie crying. Sometimes you do, and when when it's there,
(14:51):
I applaud it because I'm like, that's real. There's some
real water works. Yeah. Yeah, the sanitized crying. It's like
how in movies when an attractive actor or they like
get into some big scuffle. You know, they've been like
rolling around in the mud and all that, but then
they come up and then like their hair is still
perfect and their makeup is perfect and they still look
super great. Yeah. Uh. They do the same thing with crying.
(15:12):
There's like a sanitized unreality to crying in movies where
they they still want you to like look cool, so
they're not gonna give you like a red running nose.
They're just gonna have the single tear going down the cheek. Yeah.
And and you know, I have wondered in the past
with with certain actors who are known for this ability
if perhaps sometimes they do have some sort of a
tear duck situation that allows them to like easily produce
(15:34):
a tear without like actively engaging the rest of their
their face. Uh, because yeah, like a full on bawling situation.
Sometimes the snot that you're gonna have snot involved. You're
gonna have like red, puffy faced a situation going on.
And yeah you don't. You don't see that as much
in films, or at least not in you know, the big,
(15:55):
big mainstream films. Well, one thing I was reading about
is that some people have conditions where their eyes are
too dry, like that they don't have enough of the
standard tear fluid um over their eyes. And one way
of dealing with this is a procedure that I think
at least partially blocks the ducks that are draining away
from the eyes normally. And one side effect of this procedure,
(16:17):
if you have to get it to to help moisten
your eyes better, is that with that blockage, now if
you start crying, you don't get a running nose. Interesting, now,
this just brings to mind all sorts of of possible
nightmare scenarios where an actor is getting a bunch of
like nasal surgery done purely so that they can cry
(16:39):
on command without experiencing a running nose or or blushing
of the face. Oscar Baits scenes without the snot that
would would make them look unattractive. But I think it's
it's it's interesting that we're you know, we're talking about
the like the the physical complexity of tear production and
how integrated it is with the you know, the rest
(17:00):
the plumbing of our face, because that does match up
with a lot of what we just said about the
human emotional uh context, you know, how how our emotions
are so wrapped up in all these other processes as well.
So it feels like it feels right that these two
things should both be so indebted. You know who we are,
(17:23):
thank you, Thank now. Researchers have noted basically three broad
categories of tears that are present in humans. There are
three different ways you can make tears. The first is
what we've already been talking about, which is basal tears.
Basil tears are not a response to anything in particular. Instead,
basal tears are what is always present, is always being
(17:47):
produced by the lachrymal gland, always coating the surface of
the eye and then draining away gradually through the tear
ducts on the inner eye. And one reason we blink
actually is to help keep this ever present layer of
basal tears evenly spread out over the eyeballs. An interesting
fact I discovered about basal tears They are not a
(18:07):
homogeneous liquid. They instead consist of a number of distinct
components that tend to settle into layers. When coding the
eye and so going from the inside out, I want
mentioned the three different layers. So the first layer, the
closest your eye, is the mucous layer, and this layer
tears contain this This mucus that is I believe secreted
(18:29):
by epithelial cells within the eye itself rather than from
the lachrymal gland um, and this helps the tier film
stick to the surface of the eye. This would be
similar to the way that a lot of the tissues
inside the body have a layer of epithelial cells that
serve to secrete a mucus that helps like a lubricate
or somehow protect the inner surface of or the outer
(18:52):
surface of the organ. Then after that there is the
watery layer or the aqueous layer, and this is the
bulk of the salty ear liquid. This is secreted by
the lacrimal glands. But then on top of that there
is a lipid layer or oily layer, the oily coat
on top of the tears, So the sea of your
tears on your eye is topped by an oil slick,
(19:14):
and this apparently helps protect the liquid layer. It slows
down evaporation and so forth. So when you consider your tears,
know that they do in fact contain multitudes. However, all
of this is present even when we're not thinking about tears,
because they're not overflowing the eyelids just in the normal
cycle of of blinking and lubrication and so forth. That's
(19:37):
all just in the basal tears. What about these other
two kinds of tear responses present in humans. Well, the
next kind that you would want to look at is
known as reflex tears, or maybe irritant tears, and this
is when the eye overflows with tears in response to
a physical condition. So if you get sand in your eye,
(19:58):
or if you punish yourself with volatile sulfur compounds from
chopping onions with a dull knife. This this is the
eye detecting irritation of some kind and going into self
cleaning mode, producing lots of tears to protect itself and
to wash away potential contaminants. But then finally you get
into the most enigmatic category, which is emotional tears. Uh.
(20:20):
And and this is that this is the really strange
and interesting one, the welling of tears in the eyes
and the absence of a physical cause in the eye itself,
but owing instead to an abstract emotional state. And while
the other two categories of tears can be found in
other animal responses, it's the emotional tears that apparently, at
least according to many researchers, are pretty much unique to
(20:44):
Homo sapiens. I think it's pretty widely agreed that Homo
sapiens are the only extant animal that the cries emotionally,
that produces emotional tears, and certainly on a regular basis.
So this brings us back to this interesting question. Why
do we shed tears when we're overcome with joy or
sadness or even surprise. These things that are originally there
(21:06):
to lubricate and protect the eye and then maybe to
sort of overflow and wash out irritants in the case
of some kind of physical distress. Why would they show
up when you see a dog getting reunited with its owner.
Oh yeah, yeah, I mean I think the animal videos
certainly get to a lot of us, or or cheetah
(21:27):
and dog who are friends. It's another one. Any any
baby animal, Yeah, why why do we need It's not
like those things are are going going to admit particles
that could irritate our eyes and then our eyes are like,
oh no, here comes a cute animal. That would be
great if there was like an emotional you know. So
you just know that whenever there's a cute animal, it's
(21:49):
also emitting like oniony sulfur compounds that are gonna get
in your eyes, and so it's it's protective like that.
But no, I mean, we don't know of anything of
that kind. At least there's nothing obvious of that kind.
So you've got to look to other explanations. Though actually
there is one explanation that's that's almost certainly a bad
explanation for the evolutionary origins of tears, But I'm going
(22:10):
to mention it later in this episode just because it's, uh,
it's it's kind of funny to consider, even though it's
almost definitely wrong, but it sort of follows this method anyway.
We'll come back to that. So it seems a major
clue in looking at at the the evolutionary purpose of
tears to observe that emotional tears seem to be pretty
much unique to human beings. The Roman poet Juvenile said, uh,
(22:34):
nature in giving tears to man confessed that he had
a tender heart. This is our noblest quality. So, you know,
like the juveniles observing something unique about human beings being
able to cry, uh, noble tears, Tears that have a
meaning rather than just being like washing out irritation from
the eye sockets. This is of course something that that
(22:55):
comes up quite a bit. And Holy Tears that book
I referenced earlier from Patton and Holly, they're they're the editors,
but it contains work by other authors, other bits of
scholarship about tears and how they factor into rights and religion.
But yeah, we we tend to look at the human
condition and we say, okay, humans are capable of these
complex emotional states. They're they're capable of feeling sorrow and empathy. Also,
(23:19):
we we we shed tears in many of these emotional states.
And then we just we kind of assume that these
two things are one, that that that we we have tears,
therefore we have emotional states. We have emotional states, Therefore
we have tears and uh. And we see that bleed
over into our conception of various supernatural entities as well
(23:41):
all of our our human like creatures and beings and
myth and religion. They're all these stories of of course,
not only mythological heroes and demi gods shedding tears, but
God um itself shedding tears. Also various monsters and creatures
shedding tears tears uh and uh. And so that it's
(24:03):
interesting to take all of that and then you look
to the animal world, and I think in doing so,
we do have to stress that that ultimately, when we're
even if we're saying an animal does not shed tears,
or another like primate for instance, does not shed emotional tears,
it does not mean that they don't have emotional states,
um and and uh. And in a way that that
(24:27):
this is kind of an overstatement of the obvious, but
I think it's it's so important to drive home because
the idea of of human emotions and tears are so
closely linked, like they're just inseparable. Yeah, yeah, I see
what you're saying there, and I think that's a very
good point. You a person could naively assume, Oh well,
because if it's the case that only humans really shed
(24:48):
tears in response to emotions, that must mean humans have
like better, more sophisticated emotions than animals do, or or
more powerful emotions than animals do. You can't necessary really
conclude that, I mean one doesn't follow from the other. Yeah,
so you know, I think it. Ultimately, we can all
engage our creativity. We can imagine alien species, you know,
(25:09):
in a Star Wars or Star Trek kind of scenario.
We can easily imagine beings that have complex emotional states
at least on par with human beings that don't shed
tears like we do. Maybe they do something else that
that communicates uh, their emotional state to others. Maybe it's
a change in coloration, maybe they admit a certain odor.
(25:30):
Maybe it's some sort of a light based scenario, or
I don't know. Um if we're going to try and
come up with something that is on par with and
maybe ultimately as mysterious as why why is when are
my eyeballs producing extra liquid? Maybe it's like extra sweating.
You know, you're you're at a funeral, So what do
you do? You sweat? You sweat with everybody else? Um,
(25:52):
or you salivate a lot. That's kind of thing emotional flatulence.
I mean, there could be all kinds of like the
body could release all kind ends of substances in response
to powerful emotions. Right, But this is the adaptation that
our ancient ancestors, uh, somehow acquired, and the question would
be how did they acquire it and why? Now in
in Holy Tears, there's a there's a wonderful little line.
(26:15):
There's so many great lines in this, but I want
to read this quick one before I move forward. Quote,
among the very earliest expressions of distress in the infants range,
tears remain a profound existential signifier at all stages of
human life, particularly in the face of fear, loss, or despair.
And I think that's true. I think that that's a
that's a great statement. But I started looking around a
(26:37):
little bit, and uh, I realized, Oh, newborn babies don't
actually shed emotional tears. And this is I have to admit,
I don't have a lot of experience with the very
young children. So maybe I just haven't been around enough
like brand new babies, like less than a month old
sort of thing. But the uh, the fact seems to
(26:58):
be that the eyes of an infant remains a pretty
dry for the first two weeks of life. Now there, Uh,
their tear glands are functional, but they don't make enough
of the stuff for it to be seen as as
as obvious tears in the eye. So they might they
might be bawling, for example, and you're not going to see,
you know, the water works flowing. After two weeks, however,
(27:21):
those glands are gonna boost production, and most children, according
to Karen gil m d writing for Healthline, create full
tears between one and three months into their lives. That
is interesting because it makes you think about what are
the components of crying Again, this is something that will
probably become more significant when we talk about a lot
of some of the major theories in the next episode.
(27:42):
But crying entails multiple behavioral signals, right, So an infant
can cry and it would do a thing that everybody
would recognize as crying, and you would say, yeah, that's crying,
even without shedding liquid tears running down its face. I mean,
it will make a vocalization and you see like contortions
of the face in a certain way, and uh, kind
(28:04):
of like screaming or bawling, and everybody knows that's crying
even though the tears are not present. And yet once
you reach a certain age, the tears are present, and
we start to think of tears as an important part
of crying, especially adult crying. Yeah. Yeah, So on one level,
when we're looking elsewhere in the animal world, we have
to be very specific about what we're talking about with crying.
(28:26):
And this was pointed out by professor in comparative biology
Kim A. Bard Uh in a bit she wrote for
Scientific America, pointing out that crying has been used to
describe just the vocalization of various primates. So if you're
just very generally saying, we'll do other primates cry, well, yes,
other primates do cry out, They create vocalizations, and and
(28:47):
obviously you know these vocalizations are about communicating something, uh
to other creatures and or other primates. But if we're
indeed going to focus in on tears and quote fearful sobbing,
then humans do seem to be alone. It doesn't mean, again,
that we're the only primates capable of feelings, say sorrow
(29:07):
or other complex emotions. We don't really have a firm
answer on that count yet, but there I think there's
some some strong arguments to be made, but we're the
only ones who shed tears of sorrow right now. I
think a lot of you probably your brains went to
the same place as mind did at this point, and
I my I thought, well, what about Neanderthals. Did these
(29:28):
intelligent relatives of humans that went extinct about forty tho
years ago? Did they shed tears like we do? Right?
I mean, I guess this would be a question and
part of how far back the emotional tear adaptation goes
like did our you know, the common ancestor of Neanderthals
and Homo sapiens have this tear response that it would
(29:48):
would give to both of them or or is it
a more unique property of Homo sapiens specifically? Yeah, And
then also I think it's it's it's worth thinking about
uh and exploring to to to a limited extent because
you think about, well, what can what what what could
Neanderthals do? Like what do we know that they had
(30:09):
that human that modern humans also had? And have you know,
they had access to various technologies, they created art, and
depending on on how you look at the artifacts, they
may have engaged in funeral rights as well, so, on
one hand, it seems like a lot of the things
that we attribute to the human condition and human you know,
(30:31):
civilization even and the emotional states associated with them, we
can look to the Neanderthal world and say, well, they
had these things. So perhaps you know, so it seems
like they had emotional states like we did. But does
that mean that they could produce tears as well? Emotional
tears not necessarily a given? Yeah, yeah, so uh So
(30:52):
I started looking into this a little bit, and it's
it's interesting because the topic was somewhat muddled by some
scholarship in the mid nineties. There was I believe this
was a nineteen nineties nineties six article that came out
in p N a s uh significance of some previously
unrecognized uh apo morphies in the nasal region of Homo
(31:17):
neandertal insis. And this was from a pair of researchers
Shorts and Tattersall Okay, so uh to clarify in that title,
apo morphies would refer to unique traits, unique physical traits
of a species, right, and so this particular paper, uh,
basically what it was doing is looking at various remains
(31:40):
all of Deandertals and claiming that that there were there
were aspects of their nasal uh makeup that seemed to
be different from humans and all of their primates. And
there were so and and one of these was the
idea that peer ducts seemed to be absent. And this
caused quite a stir at the time time because oh, well,
(32:01):
this is this was this On one hand, this would
be amazing if we found this out, like what does
this mean that Neanderthals seemed to be distinct from all
other primates? Uh? And then it ended up being kind
of hijacked to a certain extent I've read by creationists
who wanted to put the spin on it. Oh, this
means that Neanderdal's they couldn't cry. Humans can cry. We're
(32:23):
the king of crying. We're the we're the only children
of God. God can cry. We can cry apes. Neanderthal's
no crying for you guys. We're the best, which the
divine spark exists only in crying. Brain Yeah, which kind
of goes back to the juvenile quote from earlier, right
like this is this is what humans do, so nothing
(32:45):
else does it and so uh that's you know, which
makes us the noblest of all is right, right. But
the curious thing about this is that it's such a
misread on the paper because, for one thing, the original
researchers here, they they were trying to make that point.
If anything, they were making the opposite point. Neanderthals were
something special, uh not human humans you know, have have
(33:07):
pretty much all the other things in common with the
other primates. Nasal features. They were saying, Oh, the nasal
features of Neanderthals. They this looks distinct. These guys are special.
So if you were going to take some sort of
religious message out of that, it seems like you might
want to say, well, then the Neanderthals were the true
children of God because God decided to give them special
nasal cavities. I don't know, But at any rate, this
(33:31):
particular paper, in this particular study, Uh, it was a
big controversial at the time. I've read and subsequently other
researchers argue that the findings were based on and this
is from a N. P. And S published rebuttal Uh,
it was based on quote reliance on specimens with damaged, incomplete,
(33:52):
or in some cases entirely absent relevant anatomy. So what
they were inferring about the supposed lack of tear ducts
in in the Neanderthals could have actually not been based
on what was something not something universal to Neandertal anatomy,
but just based on problems with the specific like skeletal
remains they were looking at, right, And you know, this
(34:13):
is just this is we see this in plenty of
other studies as well. I mean, this is just kind
of how science works. Sometimes there's something missing, it seems
seems like it might be something. Uh, paper is published
about it, and then subsequently there's kind of a course
correction on it. But I think it does. I've read
that it's still kind of remains out there. You'll still
see this brought up, particularly by some some creationist websites
(34:35):
that will try and use it to prop up this
idea that that human beings are are distinct from other
primates and therefore are not an evolved species or something
to that effect. So to be clear, Neanderthals they had
tear ducks like other primates. But the question that is
still outstanding, I guess would be did they or would
(34:55):
they have been capable of shedding emotional tears like human
like modern woman's do, and that is just that's something
I don't think we have an answer too. I'm not
sure of what we could ever have an answer to
that unless we had a time machine. Though. I guess
perhaps it's conceivable that something could be worked out with genetics.
But maybe, I mean that seems like something, Yeah, a
(35:17):
genetic marker could be possible that gives a predisposition to
a certain kind of behavior. But but yeah, that's difficult
because like emotional weeping is something that may not leave
any kind of physical trace at all that you could detect.
I mean, might it's something that's just a behavior that
may or may not have recognizable genetic markers that point
(35:37):
to it. Yeah, I guess for me, I'm I'm aloathe
to take emotional tears away from Neanderthals just because for
no other reason, it's because we have again, this is
such a strong link between tears and emotional states. Like
I don't want to just assume that Neandertals did not
have emotional states. You know what I'm saying is it
just seems because of that that bad into is and
(36:00):
we were talking about earlier. Yeah, yeah, and it seems
kind of tacky considering the rise of modern humans. Uh,
you know, may have would have played some role in
the extinction of Neanderthals, though the exact role is a
matter of debate. You know, could could just be a
matter of you see that the argument's range from out
competing them resources to like actually hunting them down and
(36:24):
killing them that sort of thing. But whatever the truth there.
I mean, as we talked about earlier, the presence or
absence of weeping as a response to emotion is not
indicative of whether or not there is underlying emotion or
the or the properties of that emotion. Now, this whole
(36:47):
discussion about ancient, ancient humans and Neanderthals has gotten me
thinking about one answer that's been given to the question
of the evolutionary origins of of tearful sobbing. And I'm
citing this because it's it's interesting and kind of funny,
not because it is a good explanation. I think this
(37:07):
is almost definitely wrong. But I came across this in
a book I'll probably refer to again and in the
next episode. This is a book by a Dutch psychologist
named ad Vinger Hoots called Why Only Humans Weep? Unraveling
the Mysteries of Tears from Oxford University Press and Vinger
Hoots is best I can tell. Seems to be one
(37:29):
of the leading experts in the world on the the
origins of crying. He's looked into this question a lot.
He's got a whole book about it, so he will
definitely come up again in the next episode. But anyway,
so he's he's running through a list of all the
different explanations people have given for for the origin of
emotional weeping. And one of these is a hypothesis that
(37:52):
was advanced by a neuroscientist and uh an expert in
emotions named Paul McLean. And so here I want to
quote from from Fingerhood summary quote. He argued that our
emotional tears originated about one point four million years ago,
when the use of fire became more common and our
ancestors burned the corpses of their beloved family and tribe members.
(38:16):
According to McLean and We're published in it was the
smoke from these fires that might initially have generated tear
producing reflexes. Subsequently, the production of tears became a conditioned
reflex due to the association of fire and ceremonies with
emotional events. Now on one level. I love this explanation because,
(38:38):
like it really works on kind of a mythological level.
This would be a great like story to tell, is
when they first started burning the smoke it got in
their eyes. You know, it almost has that sort of
folk tale quality to it. I think this is a
really bad explanation in terms of scientific or evolutionary reasoning, because,
for one thing, a conditioned response learned by our ancient
(38:59):
ancests is having to do with funerary practices. There's really
no explanation of how a conditioned response like that, a
learned response could turn into a genetically determined anatomical response
because like, you know, babies don't need to learn to
shed emotional tears from adults it. You know, clearly emotional
(39:19):
tears are something that just kind of happens naturally with humans.
It doesn't need to be learned from experiencing fires at
funerals or anything like that. Yeah, they've they've mastered it
pretty early on. It's just we we learned from them, really, right,
So yeah, it's clear it's like it's a genetically determined
behavior at this point. It is in our bodies. It's
not something that you have to pick up from culture really, though,
(39:41):
of course there are lots of cultural variations and how
exactly emotional weeping comes through. It's it's clear that there's
a there's an underlying baseline that's in our bodies and
in our DNA. Yeah. The other thing Fingerhood's points out
as a real reason to think this is not a
good explanation for the biologic origins or purpose of crying
(40:02):
is that it's hard to see how tears here would
have any additional survival value. So, right, if you're imagining
when humans they started, they started using fires and used
fires in their funeral rights um and thus came to
associate feelings of sadness and loss with irritation of the eyes,
and this made them weep, and you would have to
(40:24):
imagine that like the people who wept the most. I guess,
as you know, who got the most smoke in their eyes,
or got the or got the most eye irritation and
wept to the most in response to it would have
some kind of uh, some kind of additional survival or
reproduction as opposed to people who didn't, whose eyes didn't
(40:44):
well up a lot at at funerals where smoke was
getting in their faces, it just doesn't seem very plausible.
You can't really imagine scenarios where that leads to having
additional kids that survived further into the future. I mean,
unless we lived in a world where the the old
saying smoke follows beauty is actually true, and then you
(41:04):
might have a situation where you're like, oh, look at
Thag's eyes. He's a mess totally. He's been getting all
the campfire smoke, and he is the most beautiful, He
is the most desired made Again, it's very fun, like
the level of a kind of myth or folk tale.
But I think as a scientific hypothesis, this one just
doesn't really work. But I do think this is a
good illustration of how people are kind of scrambling about
(41:26):
for explanations of in recognizable periods of human history, Like
if humans are the only animals that produce emotional tears,
you see people wanting to find some very very characteristically
human cause of this adaptation, right, which would make people
kind of want to reach to early the examples of culture,
(41:48):
like human culture as a as a cause for it.
Though I think that's not necessarily the right place to look.
Um one more very unlikely explanation I wanted to visit
before we wrap up today. Apparently some people have used
the aquatic ap hypothesis uh to explain the origins of
emotional tears. Now, if you're interested in our our take
(42:11):
on aquatic ape, we several years back we did an
episode on this. The the aquatic ape hypothesis was originally
put forward by a biologist named Alistair Hardy, has since
been championed by scholar named Elane morgan Um. And essentially,
the idea is that a lot of the traits that
(42:33):
are unique to Homo sapiens are evolved because our ancestors
were semi aquatic. Uh. So, like they spent a lot
of time in the water, maybe fishing around for mollusks
and swimming and things like that. And this is used
to explain the relative hairlessness of humans that was for
aerodynamics in the water upright, walking was comes from waiting
(42:56):
around in the water, uh and so forth. Now, as
we concluded in the previous episode, I think that the
aquatic ape hypothesis is really really unlikely to be true
for a number of reasons. But one of the main
ones is that you would have to say, okay, well,
if humans lost all of these traits like walking around
(43:16):
on all fours and and having very hairy bodies in
order to be in the water. How come when they
supposedly came out of the water they retained all of
those adaptations to the water. You would have to come
up with ways of saying, well, uh, it turned out
those adaptations proved useful on the land as well for
some reason. But then, but then if you have that,
(43:37):
why couldn't they just have been adaptive on the land
to begin with. Plus, there's no direct evidence for the
aquatic ape scenario, so this just seems like, um, you know,
it's kind of it's fun to imagine, but it really
has no direct evidence going for it. Yeah, it's it's
it's a fun topic to to read about and to discuss,
even because it it's it's kind of like imagining a
(43:58):
scenario where you need to get across the wood. It's
from point A to point B, and uh. You know,
someone might ask, well, why can't we take this path? Uh? Well,
sometimes taking that path, you can realize, oh, this is
the harder path. After all. It seems like it's shorter,
but you have to cross a number of streams to
get there. You have to you have to do a
lot more work, even though at the on the outset
(44:18):
it seems like it is the most straightforward path. Uh,
it's not. But then and then the other thing about
it too, is that the aquatic aphypothesis, why you know,
who will incorrect. If you learn about it, you do
learn about other other scientific topics that are accurate. I mean,
you are learning a little bit about about the evolution
(44:39):
of aquatic mammals and so forth. It just doesn't have
anything to do directly with what our bodies have done. Like,
it's still beyond amazing to to look at a whale
and realize that this was once a kind of shaggy
wolf type creature living living along the shore and catching
fish in the water. Uh, and that eventually it would
(45:02):
it would become this, you know, behemoth, this leviathan. Uh,
you know the ocean. That's that's amazing stuff. Oh yeah,
it is. Uh. And and you know, it's it's a
very it's very seductive because it's cool to imagine humans
becoming like semi aquatic creatures and and adapting this way.
I mean, I think the aquatic a hypothesis is uh,
(45:25):
despite not having a lot of explanatory power and no
direct evidence for it. I think it's attractive to people
on the same basis that, for example, a lot of
like conspiracy theories are which is that this is something
I know I've said on the show before, but I
think a lot of times people underestimate how much people
believe certain things because it's fun to believe them, sort
(45:51):
of like entertainment or interest. First theory of epistemology that
people are attracted to certain explanations of the real world,
not really because of anything about how well they explain things,
but because it's pleasurable to believe certain things about the world,
Like entertaining certain theories like the aquatic ape theory is
(46:12):
kind of mentally exciting. Yeah, yeah, absolutely. I mean these
various sort of fringe hypotheses, you know, some of which
that we've explored on the show before. They can they
can almost fill the space of religion in in the mind,
you know, they can be this this thing that I
think ultimately that's perhaps the healthier way to to correspond
(46:33):
with some of them, to say, uh, you know, for instance,
I really like the aquatic ap theory. Do I think
it's real, No, but I think it is an interesting
topic to look at, and perhaps you can even expand
on it and imagine fictional worlds in which this is
the path that human evolution took. I don't know, totally
totally yeah, um, so, anyway that the the the aquatic
(46:54):
ape hypothesis encompasses also, among the many things it purports
to explain, it has been alleged that it also explains
uniquely human tear traits. Um. But I guess maybe we
need to wrap up the first part here, But when
we come back in the next episode, we can talk
about some of the major theories leading theories today about
(47:15):
why humans shed tears as an emotional response. And there's
also something I want to look at in the next
episode which is very interesting. What is the origin of
the concept of crocodile tears? There's a lot of fun
in this. Uh, just one little teaser on that. Apparently
some ancient and medieval sources alleged that as a crocodile
(47:35):
was eating an animal, or maybe even eating a human,
it would shed tears in order to tender rize the
head of the animal it was eating. I don't know
how that allegedly works, but oh wow, all right, well
that that sounds like it'll be fun more on this topic,
but with a little uh medieval uh medievalism thrown in
(47:56):
there as well. So yeah, I'm looking forward to it.
In meantime, if you would like to listen to other
episodes of Stuff to Blow Your Mind, you'll find them
all in the all the episodes and the Stuff to
Blow Your Mind podcast feed you'll find out wherever you
get your podcasts. We have core episodes on Tuesdays and
Thursdays and rerun on the weekend, Artifact episode on Wednesday,
(48:16):
listener mail on Monday, and on Friday's we do a
Weird House Cinema episode. That's our time to set aside
most of the science and just talk about a weird movie.
Huge things. As always to our excellent audio producer Seth
Nicholas Johnson. If you would love to get in touch
with us with feedback on this episode or any other,
to suggest a topic for the future, or just to
say hello, you can email us at contact at Stuff
to Blow your Mind. Dr. Stuff to Blow Your Mind
(48:45):
is production of I Heart Radio. For more podcasts for
my Heart Radio, visit the iHeart Radio app, Apple Podcasts,
or wherever you're listening to your favorite shows. By the
present joint four point four PC first FO
Stuff To Blow Your Mind News
Hosts And Creators
Robert Lamb
Joe McCormick
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