March 27, 2021 • 51 mins
Humans are feeling creatures, constantly awash in a sea of emotion. We struggle to understand the waters that suffuse us, but what about other denizens of the animal kingdom? What about the octopods? In this Stuff to Blow Your Mind two-parter, Robert and Joe explore the question of invertebrate emotions. (Originally published 3/17/2020)
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Episode Transcript
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Speaker 1 (00:05):
Hey, welcome to Stuff to Blow Your Mind. My name
is Robert Lamb and I'm Joe McCormick, and it's Saturday.
Time to go into the vault for a classic episode
of the show. This one originally aired March seventeen, and
it's the second of our two part series about invertebrate emotions.
So we hope you enjoy and maybe fall in love
with the slug Welcome to s About to Blow your
(00:29):
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 we're back with part two of
our exploration of invertebrate emotions. In the last episode, we
talked about the paper Nautilus or the argonaut. We read
(00:49):
that great Marion more poem. We talked about what emotions
are the difficulties and studying them, and we talked about
anecdotes about people really seeing personnel, pity, character, and emotion
in octopuses, but then also scientific studies looking for certain
types of measurable cognitive effects of emotions or emotion like
(01:10):
states in invertebrates like bees. We talked about the judgment
bias test and how bees might have biases that come
about in optimistic or pessimistic ways based on how they're
quote feeling. Yeah, A big part of the conversation last
episode was I think, ultimately about stripping down emotion to
something that doesn't depend upon the subjective human experience, and
(01:33):
in doing so something that I don't want to make
it sound like we're, oh, we're just we're cutting out
all the important stuff. I think a lot of what
we're cutting out is the poetic stuff, the the the
the extra like self contemplation stuff, and getting down to
the root of what is an emotional state, how does
it affect um our behavior and our expectations, and then
(01:55):
you know, how do we see that echoed in other organisms? Right? Well,
we're cutting out yeah this by cutting out the subjective element,
We're cutting out the part that would be impossible to
study in other animals and just trying to say what
our emotional states as manifested externally. Yeah, But of course
the difficulty, as we discussed, is by taking out the
subjective aspect of it, we're taking out the part that
is closest to us and the thing that you instantly
(02:17):
think about when we even say the word emotion of course,
sweet emotion. Oh no, that song fills me with bad emotion,
did you. Oh, I don't know if I ever gotten
to do this rant before. Y'all know I hate Aerosmith.
Oh no, I don't know. Well, I think you may
have mentioned it once in passing. Yeah, even even the
early stuff. I don't know. I mean, I can be
(02:37):
that classic rock radio uncle, like you know when led
Zeppelin comes on, I'm like, yeah, I feel it, but
I don't know that something about Aerosmith just turns my
head three sixty degrees. Well, I have to admitted really
like a dream on. That's that's if I hear that
one on classic rock radio, I'll tune in and listen. Well,
I'm glad you like it. Hey, folks, this is Joe
(02:59):
from the Few. You're swooping in to alter the past.
Sorry about the audio, but I realized on listening back
to this episode that in our excitement about the topic,
we forgot to reintroduce the paper that we were talking
about in the first episode, and then we're gonna be
talking about throughout this one as well. So that paper
was by Clint J. Perry and Luigi Bachi at Donna
and it's called studying emotion and invertebrates. What has been done,
(03:23):
what can be measured, and what they can provide. It
was published in the Journal of Experimental Biology in Okay,
now back to our original conversation. Okay, But so the
last time we talked about one of the main three
branches of external ways of studying emotions and animals. We
talked about you know that they're they're perhaps cognitive effects
(03:45):
of emotions, that emotions affect how you perceive the world
and how you think. That there are behavioral tests of emotions,
that emotions affect how you act, and that there are
physiological tests of emotions that emotions affect involuntary physical reaction
in the body. And we last time we looked at cognition.
This time we're gonna look at the other two. So
the first would be behavioral tests behavioral signs of emotional states.
(04:10):
And one of the things that I think we should
first acknowledge is that I'd say, this is the primary
way that we sense emotions in other people. What do
people usually do with their bodies, especially their faces, when
they're feeling various emotions. But as the authors point out
quite helpfully, they say, quote invertebrates lack the facial musculature
(04:31):
for any real type of comparisons to be made in
this regard, so I think that the jury is in.
You can't tell if a hornet is smiling. You can't
tell if there is disgusted on the face of that crab. Yeah,
I mean, as if a crab had a face anyway. Right, Um,
but my flogging that horse again, it's not really a
horse I flog. But no, no, no no, Actually, you're right.
(04:53):
I think i'd agree the crab. I don't know crabs
pushing it. I don't know if a crab has a face. Yeah,
I mean, it definitely has the front of a head,
But that front of a head with the crab is
not really it's not used for communication. Crabs depend on
sound as well as you know. The claw waving and
overall movement displays general body language, but predominantly sound is
(05:15):
their their form of communication. The wasp for their part, uh,
they depend primarily on smell for communication. We will get
into that a little bit in the last episode with
the bees. So their communication since realm is not really
our own. Um, they exist in a in a different
realm in that regard, right, But the behavioral effects of
underlying emotional states are not limited to facial expressions alone,
(05:39):
just because that's maybe the main way we see emotions
in other people. Uh, the author's right quote. A substantial
amount of work in mammals has utilized other bodily expressions
and motor behavior in response to stimuli to assess both
valence meaning the pleasantness, and intensity meaning the level of
arousal of emotions. And I really think the horse is
(06:00):
a great example of this for a couple of reasons.
First of all, the horse is an animal that is,
that lives in close proximity to humans, that is adored
by humans. That is, that is often you know, championed
as being this next to the dog and you know
the cat, I guess it is. It is a friend
of humanity. And uh. And my wife being super into
horses and pretty knowledgeable about them, she's just told me
(06:22):
about some of this before, but I was I also
looked up a source on this for this episode How
to Read Your Horses Body Language by Jennifer Williams, PhD
for ACQUSS Magazine, and Williams points out that if a
novice were to view a skilled horse trainer in action,
they might well guess that this individual is psychic or
has some sort of mystical Cormac McCarthy in connection to
(06:45):
the soul of the horse, you know, the deep, dark,
mystical soil soul of the horse. But it's really all
about knowing how to read these other signs, the overall
body language of the horse and then these other sort
of non facial or semi facial cues. Well, yeah, I mean,
I think if you're a dog person, if you've got
a dog in your house, think about like, how finally
(07:06):
a tune you are to your dogs feelings, levels of excitement,
motivations and and quote emotional states or you know, there's
something that is analogous to these emotional states. Uh that
if somebody who had never met a dog before or
hadn't spent much time around dogs saw you interacting with
your dog, they might well think the same thing. You
must be psychic. Yeah, but no, A lot of it
(07:28):
is about picking up on all of this language, or
indeed just knowing what to look for. So in the
case of the horse, for instance, Um, your position is
very important. Is one of the apparently the first things
you tend to learn about about understanding a horse's emotional state,
so that the ears may face forward, meaning they're interested.
They may be pinned back, meaning they're angry and they're
prone to bite or act you know, aggressively slash defensively. Uh.
(07:51):
They might be turned out to the side, meaning they're relaxed.
They might be turned back but not pinned, and this
means they're listening to something behind them, and it also
means they might decide they need to turn around to
go look at it, and horses, being large animals, it's
something to be aware of. Uh. And then they also
might be rapidly swiveling, meaning that they're anxious or at
their you know, at a high level of alertness. But
(08:13):
then on top of that there's also head carriage head
maybe lowered elevated snaking. You have to consider four leg
and hind leg movement and position, muzzle activity, which this
some of this gets more in line with what you
might expect from a face, you know, like what are
the nostrils doing? Uh, you know, what what's the mouth doing,
what are they doing with their teeth? That sort of thing.
There is a certain level of like what are their
(08:35):
eyes doing? Uh? You know, to someone that doesn't really
know anything about horses, it's easy to sort of think
of the eyes as being sort of like big empty
glasses without a lot of emotion. But there is stuff
you can read into it. There's the movement of the tail,
and then there's just general whole body stuff like what
is the overall bodily tension of the animal, how is it,
(08:55):
how is it moving and uh, And you can really
take all of that and read into the emotional state
of the horse. But if you just look at you know,
what you might be tempted to call the face of
the horse, you're not necessarily going to pick up on
on all those cues you have. And I think part
of this two gets we have to think about the
human situation. So clearly humans have body language. You know,
(09:16):
there's more than just the facial communication array with human
beings totally, but we do depend on the facial communication
array a lot, and we do fixate on it to
a very large degree. But basically, what I'm trying to say,
using the horses in an example, that there are there
are there are various parts of an organism that you
can look to to to figure out what their emotional
(09:39):
state is, and it may or may not be something
that matches up with the human idea, the idea of
a face. Yes, so what would be some of these
external behaviors that we could measure in invertebrates. One of
the most obvious behavioral signs of underlying emotional states and
animals is retreat behaviors. So but you know, like in
(10:01):
fear or anxiety, animals will retreat, retracting or covering vulnerable
body parts, adopting defensive posture, and running away. These are
some of the clearest ones to look for in all
of animal behavior. And so the first example cited by
the authors here looks at exactly that. And it's actually
a study we've already mentioned on this show before. It
(10:22):
came up in our episodes titled Devour of Memories. Remember
that about about the plenaria and the and the research
about whether you could gain somebody's memories by eating their body.
Uh So in this episode that we mentioned to study
about a type of large sea slug called the California
sea hair or Aplasia californica. Uh And in that other
(10:43):
episode study came up because it demonstrated associate of learning
and classical conditioning in an invertebrate sea slug. So you
offer a sea hair some delicious shrimp extract. But in
the test group, well, the sea hair is munching on
the shrimp extract, it gets an electric shock to the
head that this painful stimulus results in not a frown,
(11:05):
of course, but measurable behaviors in the slug. It withdraws
its head, it withdraws its siphon, It inks, and it
moves away from the shrimp at extract. And sure enough,
if you train it on these associations. When simply when
the animals from the test group are simply presented with
shrimp extract, they will pull back the siphon and move away.
(11:28):
By the way, see hair and the electric shrimp extract
would be a great name for a band. Just put
that out there. I think that was a Bob Weir
side project. Wasn't ok um. But whether or not, it
makes sense to use the same word we use for
emotions and other mammals. Quote the observed behavioral responses to
conditions stimuli resemble the actions of conditioned fear in mammals. Subjectively,
(11:51):
it might not make sense to talk about fear in
a sea slug. We don't know, but it certainly behaviorally
looks like fear. It looks like the same thing we
recognize this fear in mammals or in other humans. Because
of course, nothing about the shrimp extract itself causes pain.
It couldn't be a simple stimulus response. It has to
be this association with pain, the memory of you know,
the fear caused by the memory. And a lot of
(12:13):
invertebrate studies into emotions look for signs of fear because
fear is easier to study. Presumable fear inducing stimuli are
relatively easy to create, and behavioral responses are relatively easy
to detect. There's another example that the author's site here,
which is fear research into Drosophila also known commonly as
(12:34):
fruit flies or as vinegar flies small fruit flies. UH.
This is an extremely common organism for lab research. You'll
find tons of studies UH modeling other things in complex
organisms as they appear in Drosophila. So in twif Gibson
at all studied fear and Drosophila caused by the stimulus
(12:54):
of an overhead shadow, they used a rotating opaque paddle.
I don't know if it was a ping pong paddle.
I kind of hope it was. It was some kind
of paddle that would be made to rotate in a
circle in in in a steady progression, repeat passages over
a container of these these flies that would be as say,
eating a food source or something. And the authors found
(13:17):
that multiple repetitive exposures to this overhead shadow caused the
flies to fly around more, to hop more, to freeze more,
and to fly away from a food source. And there
was evidence in this study that the passing shadow led
to a generalized internal state. The more times the shadow
passed over, the more avoidance responses happened. So it looks
(13:40):
like within the flies it wasn't just stimulus response. The
shadow passes, then you fly away. If you are repeatedly
subjected to this stress inducing stimulus, the flies appear to
enter a state where they're just they're just in a
semi permanent way agitated. They're flying around there there of
leaving the food source. It looks like they have the
(14:02):
internal state of being afraid, and the avoidance responses remained
remained more elevated. Even after the stimulus stopped. The shadow
would stop passing over, and for some time afterwards, the
flies acted more agitated, more likely to fly away from
the food source than flies with less exposure to the shadow,
and this makes it seem as if the avoidance reactions
(14:23):
were not just the direct immediate response to the shadow,
but also influenced by this internal state within the flies
nervous systems, which is similar to how fear works and
humans and other vertebrates. Something jumps out and scares you,
you have an immediate response, maybe you shriek, maybe you
pee a little, you know, maybe maybe you jump, But
then you also remain in a state you're on edge
(14:46):
for several minutes afterwards, showing these anxiety behaviors even when
the scary thing is gone or no longer represents a threat. Unfortunately,
this is a lot of how we live our lives actually, Right, Like,
there's something that kind of like startle as you, gets
you on edge, and maybe it's not even something that
would be a physical threat. Maybe it's just a conceptual threat.
You know, you get an email or a tweet or
(15:07):
anything that kind of puts you on edge, and then
you just stay that way for a good long while. Yeah, yeah,
all day generally. Yeah, what happens when you reach for
your phone first thing in the morning, right, and I
think that that's an important thing. It calls to to
attention the difference between fear and anxiety. Fear, of course,
is a response to the perception of an immediate threat,
(15:29):
a clear and present danger, and it results mostly in
escape behaviors by animals. You're trying to, you know, defend
yourself and get away. Whereas anxiety is related to fear
but slightly different. Fear is a response to the clear
and present danger. Anxiety is a response to ambiguous, imagined,
or potential threats. When there's a threat that's not necessarily
(15:52):
right in front of you, but you imagine it might
be waiting nearby, it might be around the corner. Yeah,
it's kind of lurking in the the the information sphere
around you, as opposed to being right there in front
of you. Uh. And and of course they bringing back
to the human experience, we have no shortage of Fear
is just sort of rotating around us in the information sphere.
(16:14):
And this state of anxiety actually brings us to the crawdads.
I know, we promised we'd we'd get there eventually, a
k A crayfish a k A. Mudbugs. Did you grow
up calling them mudbugs? No, this is what I've just
heard them called. Did you catch them in the creek? No?
I know I was never around them growing up, but
I have family that lives in southern Mississippi, and you
(16:35):
know they're they're all about them, uh down there. In fact,
I've been to and then this will this will be
like an image to come back to. As we discussed
their possible emotional states. I went to a Marty Groppard,
not the main Marty grap right, but I like, you know,
one leading up to it in southern Mississippi, and there
were like games where live crawfish were thrown by children,
(16:59):
like they road crawfish back and forth at each other
and then occasionally fall onto the concrete and all. And
um yeah, at the time I thought it was weird
and kind of barbaric. So man, maybe I'll feel even
more so as we discussed their their their inter emotional
states here, so it gets turned inward as well. Though.
Do you ever play the game I assume you didn't
or see people play the game where you just let
(17:19):
a crawdad pinch, you know, just like let it pinch
your nose or your finger or something. Did you do
this growing up? Uh? No, but I had friends who did.
Where was this in Tennessee? They were to carl crawdads
just in the creeks. Well, I guess there were probably
a different species, I'm not quite sure than the one
we're about to talk about, but yeah, there were some
kind of crayfish shaped organism living in the creeks freshwater creeks. Yeah, okay, yeah, yeah.
(17:44):
My main experience with them is just occasionally eating them
as an adult. Um, but that's about it. Never got
to play with them as a child. But for anyone
out there who does doesn't, it still doesn't know what
we're talking about. It's essentially a small crustacean like a
fresh a small fresh water only lobster, right, yeah, tiny lobster.
The specific uh species that's going to come up in
(18:05):
the in the research we're getting to is Procamboris clarkey.
And yes, these are the crawlfish of the famed Louisiana
crawfish boil. So I don't know if they were if
they were boiled up with some zatarans and eating after
the test there. I should also add that sometimes you'll
see crayfish in aquarium settings and they can be quite
beautiful as well. So you know, I don't think human
(18:27):
and humans humanity. Relationship with the crayfish is mostly uh,
mostly something that revolves around eating them, but sometimes you'll
see them as pets. Now, to come back to the
idea of anxiety, we were talking about the difference between
fear and anxiety. You know, we're saying fear often results
in escape behaviors. Anxiety is often thought to result in
(18:47):
conservative or defense behavior, for example, to limit openness and
to limit exploratory behavior. Animals in an anxious state are
more likely to seek out closed familiar and protect it
in environments, whereas animals in a non anxious state are
more likely to explore unfamiliar and open environments. And one
type of experiment that has been used to study anxiety
(19:10):
in animals like rats and mice and now in crayfish
is the elevated plus maze. So, Robert, had you ever
seen one of these before? I don't think I'd encountered
one of these before, and I don't remember encountering one
in a study. I've certainly never been in one. So
you imagine a simple platform in the shape of a
plus sign. You've got two arms of the plus sign
(19:32):
that are enclosed by walls, and then the other two
arms are open. They're just straight platforms without walls. And
this shows up in all kinds of studies. How an
animal moves within an elevated plus maze or EPM can
be manipulated by lots of variables that are thought to
control anxiety. The more time the animal spins in the
(19:53):
closed section enclosed by the walls, you know, sort of
protected and hidden, usually the more anxious and is thought
to be. And many animals, maybe most small animals, tend
to prefer dark, enclosed places. These are the types of
places that they are more likely to be protected from
predators in their natural environments. Like the rat in your house,
(20:15):
it likes to hide inside the walls and behind the
fridge and stuff. It doesn't like to hang out in
the middle of the floor, right like a wide open
spaces that's where a hawk can swoop down and pick
you up. That sort of thing. Right. It will only
venture out into the open spaces in order to explore
and seek rewards. It might go out there if there's
food in the middle of the floor, um, But if
(20:36):
it sees something scary, what does it do? It runs
to an enclosed space. The more an animal like a rat,
has an induced state of anxiety due to an ambiguous
or possible threat, the more it will tend to confine
itself to dark, enclosed spaces. And conversely, the less anxiety
it has, the more it will feel free to explore
open spaces. Uh. And the e p M is widely
(20:57):
used in studying animal anxiety and in the test sting
of anti anxiety medications. Now here's where the crowd ads
come in. So the elevated plus mayze has been widely
used in anxiety research like we're saying, and almost all
these studies have been on vertebrates, but since there have
been at least two studies using the plus maze test
on crayfish. Again, this is procam Boris Clarkey, and the
(21:21):
updated design used an elevated plus mayze submerged in water
with the enclosed arms shaded so that they were dark
because in their protected environments, the crayfish like dark places.
That's a natural defensive preference they have. So there were
a couple of studies. One was Fawcett at all in
fourteen and one was Bacquey casanave at all in seen
(21:45):
and They both found that if you subjected the crayfish
to frightful stimuli ahead of time, they would spend more
time in the shielded, dark, enclosed areas of the elevated
plus may so the examples were mildly painful shocks and
harassment by a larger crawfish. So like, if you take
a smaller crayfish and then subject it to a bigger
(22:06):
one doing dominance displays, the one, the little one, the
one that is being harassed, will tend to spend more
time in the enclosed area in less time exploring the
open platforms. And the authors right quote. These behavioral results
fulfill criteria normally designated for anxiety and mammals, including being innate,
being unconditioned, occurring in the absence of a stressor, and
(22:28):
expressed in a novel context. Al Right, so in this
experiment we see the evidence that a crayfish, something we
don't think of as having emotional states, really ultimately has
something very similar that to the the fear that is
experienced by a mouse or a rat, and therefore very
(22:49):
similar to what we experience. Right, So it's not just
stimulus response. I mean you could you might imagine that
an animal without emotional states could say retreat in the
immat term from something that's threatening it by going into
an enclosed space. But even afterwards it seems to remain
in this internal state where it prefers to stay in
(23:10):
the closed protected spaces and does less exploring than a
control crayfish if it has at some recent time been
threatened or harassed. It sounds like a familiar story. Yeah, yeah,
Like like I say, if we take away sort of
the the holy human qualities of fear, uh and and
look at it objectively, like this's what we're looking at here,
(23:33):
We're looking at the fear of the crawfish. Well, maybe
we should take a quick break and the when we
come back we can discuss the joy of the fire. Ant. Alright,
we're back. So the authors of this study we've been
looking at point out one shortcoming of the existing body
of research on animal emotions, and it's that it is,
as on the whole, overly focused on negative emotions. Quote.
(23:57):
It is argued that the reasons that positive and motions
have been neglected in research, or because they are few
in number, reflected even in the imbalance of English language
words for negative over positive emotions and are harder to differentiate.
The asymmetry might also stem from our understanding that natural
selection has shaped emotions more for survival than for prosperity.
(24:20):
There are many more threats than treats in our environment. Also,
they point out that if we're looking for tests mirroring
work done on humans, most psychological and clinical work in
the history of science has been focused on solving problems
rather than on studying ways in which people are doing fine,
all of which I think is probably true. I mean,
(24:40):
I think all of those reasons are valid. But despite
these limitations, it would be great to have more research
attempting to understand positive emotions or the state's analogous to
positive emotions in non human animals and invertebrates. Like, it's
just kind of a bummer and kind of limiting when
it's overwhelmingly research on fear and aversion. Yeah, that's an
interesting point about like even the the the English language
(25:04):
bias for negativity as opposed to positivity. Uh, it makes
me think of going to our our neighborhood reality the
only video rental store in the city or state video Drume.
Video Drum has a sizeable horror selection, and I love
to lose myself in it. But what is the opposite
of the horror section? There's not really one. I guess
(25:26):
what the maybe the comedies but Robert Altman section. Maybe that.
I mean even you know, any comedy, any drum, anything
that's not like straight up like a little kids cinema.
I mean, to whatever extent that exists, like anything that's
not just teletopies is going to have risk and danger
and these negative emotions that are there to at least
propel the corresponding positive ones. Yeah, I think you're exactly right,
(25:50):
And I think the point they're making is a good one.
That it's not necessarily that there's more, you know, uh,
negative emotion than positive emotion in human life, but that
for some reason we're more we're happier to let positive
emotions all kind of blend together and be the same thing.
They're all just you know, there are a million different
forms of happiness and joy, but we don't have as
(26:11):
many differentiated words for those states, you know, whereas you know,
we're we're very into getting down in the nitty gritty
of different types of ways to feel bad. Well, I
guess one of the it kind of comes back a
little bit probably to something we've discussed before, the idea
that when you're happy, if you contemplate about your happiness,
(26:31):
if you stop to consider your happiness, then it goes away.
But if you don't need to think about it too much, yeah,
you don't really have enough time to get to nuanced
in the language. Whereas a negative, a good negative emotion
will just really sit there and you can get to
know it. You can you can really uh, you know,
formalize your relationship with it. Yeah. Now, on the other hand,
(26:51):
there have been a few studies that have gone against
this trend of focusing overwhelmingly on negative emotions in these
animal studies. For example, in the last st episode, we
talked about the one cognitive tests, the judgment bias test,
that at least appeared to show the cognitive effects of
something like pleasure or happiness in the bumblebee. You remember,
it was like, if you give the bumble bee a
(27:13):
free treat, give it some free sugar, it will tend
after that to at least appear to have an optimistic
bias to interpret ambiguous information as as being something good
or approachable. The next line of research involves the behavior
and ants that some researchers think may be associated with
an internal state analogous to happiness or joy. Uh so,
(27:35):
what might the dreaded fire ant have in common with
your favorite cute puppy wagging? Butt wagging? Do tell, Do tell? Alright?
So the red imported fire ant or Solenopsis invicta, has
displayed a very interesting behavior observed by a number of researchers,
reported in a study in sixteen by Debbie Castle, christophord Liu,
(27:58):
Hun Daniels, Shiftman, and S. Bradley Vincent called a Study
on Abdominal Wagging in the fire ant Solenopsis Invicta with
Speculation on its meaning in the Journal of Bioeconomics. So,
the researchers were just watching lots of hours of video
taken from inside a fire ant nest, and from these
(28:19):
observations they started to notice a pattern of behavior where
the ants inside the nest would basically stick their butt
up in the air and wave it around. Quote they
position and move their abdomen up and down at forty
five degrees, and they called this behavior wagging. Now raising
and wiggling the abdomen has uses in other contexts for
(28:42):
fire ants. You may have seen fire ants doing this defensively.
The abdomen or back segment of the body is also
known as a gaster, which is great like Charles Dickens name,
you know, like like William Gaster uh And outside the
nest the behavior is known as gaster flagging. They'll flag.
Usually involves raising the abdomen up higher something more like
(29:03):
ninety degrees. Flagging is apparently used during foraging to disperse
venom into the air, and it's believed to deter other
insects like competitor ants from the foraging area. So you're
out trying to gather food for the colony and then
some other ants come in, you will stick your butt
up in the air and spit some venom out into
(29:23):
the air to try to drive the other ants off.
There's also some evidence that some abdominal wagging or gas
or flagging emits a sound as the gaster joint rubs
across itself, and this would be a tiny, high pitched squeak.
We're not sure what role this sound plays, but it's
possible that has a It has a role in communications,
such as calling for help when an ant is trapped
(29:45):
or when it's in trouble. However, Castle at all believe
that in their observations, the inside the nest wagging behavior
was not defensive in any way. Within the nest, they
found that the wagging emitted neither sound nor um, no squeaks,
no toxins, and the stinger was never extended during this period.
So if they're just wagging around and has nothing to
(30:08):
do with the other types of wagging that these ants
normally do, what's going on. Furthermore, they found that the
inside nest wagging happened primarily when the ants were engaged
in two activities, eating sugar or tending to the brood
in other words, taking care of the young. Well, those
are two pleasurable experiences just for humans, sure, And they
(30:30):
did not find any evidence of nestmates reacting to the wagging,
so they couldn't detect any role for communication in the wagging.
So what's it for. Well, the author's hypothesized that quote
this in nest behavior might be analogous to facial expressions
and bodily postures of hedonic pleasure in humans and other
(30:50):
mammals during pleasurable events. So that's a very interesting idea.
Perhaps a fire ant smiles by wagging its gaster in
the air. Now, we should definitely acknowledge, and the researchers
do acknowledge that this is far from proven. That there
are a few other possibilities to Maybe the wagging is
some kind of mechanical reaction in the body to certain
(31:12):
uses of the mouth parts, so that the mouth parts
would be engaged during eating or during tending to the brood.
Maybe something's happening that just happens to make their butt
wiggle in the air at the same time. So it
would help if this could be paired with other types
of tests. For example, would consuming sugar water or tending
to the brood also cause the fire ants to have
an optimistic bias in judgment bias tests? That would probably
(31:36):
strengthen the case for this wagging as a bodily expression
of something like pleasure or happiness. But I love the possibility.
Maybe the ant smiles with its But but again, this
would this would come down to a It's some physical
body language that is observable that would potentially demonstrate the
(31:56):
emotional state of the creature, right, and it would helpful
if you could pare it with other things that were
presumed to be associated with that same state. Now, another
one about positive emotions comes back to bumble bees, which
we mentioned in the last episode. Remember earlier there was
this research seeming to indicate the giving a bumblebee some
free sugar would result in an optimistic bias in these
(32:17):
cognitive tests. Another test on bumblebees looked at the effects
of sugar water on behavior after a stressful event. So,
in the wild, bumblebees are subject to ambushes by certain
sit and wait predators, such as the crab spider. Have
you ever seen a crab spider in action? I'm not well.
So they will tend to wait on a flower, uh,
(32:39):
and they'll just kind of blend in there among the
petals that they've got these wide legs, uh for a
big hug. And then when the bee lands on the
flower to try to get some nectar, the crab spider
will grab it with its legs and try to bite
down and kill it. And a lot of times in
natural encounters, the bee is briefly captured by the spider,
(33:00):
but then manages to escape. So, in a twenty sixteen experiment,
Perry at All created a simulation of a crab spider
attack by putting together a mechanism that would ambush and
trap a bumblebee for three seconds before releasing it unharmed. Now, obviously,
after a stressful brush with death like this, the bee
will take some time before it again begins to forage
(33:23):
and start landing on flowers and stuff. And what Perry
at All found was that a treat of sugar water
given before the attack would shorten the duration of this
cool down period after the spider attack. So if a
bee gets a sweet treat before a simulated spider attack,
it takes the bee less time to reinitiate landing on
(33:44):
flowers and feeding after this stressful event. Now, again, there
could be other interpretations of what's happening here. Maybe somehow
the nutrition and the sugar makes the bee physically stronger
and less vulnerable, etcetera. And maybe something like that. But
one possibility is the the pleasurable stimuli of the sugar
water puts the bee in something analogous to a better
(34:05):
mood or emotional state, making it more resilient to stressful setbacks,
which I think is something that we're probably all familiar
with ourselves. Right, you know that your emotional state is
uh dictate strongly how you will react to negative incoming events, right, Right,
The same thing that floors you one day, I'll just
kind of bounce off you another right, right, Or if
(34:26):
you've had a particularly bad day, then bad news is
going to you know, have a more negative effect on
your well being right now. The authors identify vocalizations and
sound as a possibly very fruitful behavioral avenue for future
research and invertebrate emotions, noting that Charles Starwin himself speculated
in eighteen seventy two that quote, insects might potentially communicate
(34:48):
emotions such as anger, terror, jealousy, and love through their stridulation,
you know, the great rubbing together sounds that insects make.
So what does a jealous cricket sound like? I'm not sure,
but it's easy to imagine all the various anthropomorphic interpretations.
So regarding our our ideal cartoon cricket, I'm sure. Do
(35:10):
you even remember how in the original Pinocchio, Pinocchio kills
the cricket with a hammer? What? Yeah, the cartoon or
no story? Not? No, no, not in the movie the
movie changed it made it nicer in the original story.
Jimmy cricket, Yeah, oh man, I don't remember if he's
named Jiminy cricket. I think he's just a magic cricket
and Pinocchio kills him with a hammer. I didn't even
(35:32):
know that Pinocchio is in one of his bad phases. Uh.
You know, I don't think I like Pinocchio. I don't
have a lot. I don't have a strong affinity for
the Disney version either. The only thing that I have
a strong affinity for is Jimmy crickets role in the
Mickey Christmas Carol, in which he plays what the ghost
of Christmas past? I believe, I don't. I don't know
(35:52):
if I ever seen that. You should see. It's like
thirty minutes long, and it's it's a pretty good, streamlined
adaptation of Chris was Carroll. I'm sure it's better than
the other thirty minute version of a Christmas Carol I've seen,
which is called the Christmas Carol and it's narrated by
Vincent Price. It's very bad. Man. Well, later this year,
when Christmas frows around again, I think we should do
(36:12):
an episode on a Christmas Carol. I think there's a
lot to discussed there. Okay, well, maybe we should take
a break and then when we come back we can
talk about physiological tests than Alright, we're back. So we're
entering the final phase here. We're going to be discussing
physiological tests for emotion. Right, so we've talked about cognitive tests,
(36:33):
we've talked about behavioral tests. Physiological tests for emotion uh
in people, they look for correl It's between reported emotional
states and automatic responses in the body. So, for example,
somebody jumps out at you with a werewolf mask. You're
not just gonna jump back. It's not just gonna maybe
give you a pessimistic bias. But you will also have
increased heart rate, release of stress hormones like nora ep
(36:54):
and effer and and cortisol, dilation of the pupils in
the eye. You might be a bit you know, by
just stuff. I know a lot of this is because
it's not just that you saw a werewolf. It's that
your body is preparing you to fight a werewolf or
run from a werewolf. Right, The fight or flight response
kicks in and and it entails this cascade of automatic
reactions in the body, things that you don't control behaviorally.
(37:16):
They just happen without your say so. And these physiological
responses can usually be measured objectively pretty easily, which is
very handy. However, physiological responses alone can be They can
be hard to use to identify individual emotions. For example,
if you're measuring a heart rate, heart rate might increase
in response to anxiety or to joy. The fact that
(37:38):
the heart speeds up it's beating tells you there's some
kind of arousal, but it doesn't necessarily tell you which one.
The person's heart could just be full of song, right.
So sometimes if you look at enough different physiological responses
at the same time and compare them, you can start
to zero in on specific emotions, but not always. And
(37:59):
just like it's to translate research on human facial expressions
to invertebrates, it's also hard to do so with human
physiological responses to emotions. Uh. The authors write, quote, most
of these types of measurements are quite difficult to apply
to invertebrates given their often miniature size and hard carapaces, and,
in the case of insects, an open circulatory system where
(38:20):
heart rate is not increased. But there has been some
interesting research. Nonetheless, they cite a bunch of it just
to pick out a couple of examples. Keita at all.
In two thousand eleven did research on fear conditioning, this
time in pond snails, very expressive species. Uh. They condition
the pond snails with an association between sugar water, which
(38:42):
normally you give some give some sugar water to them
and they will start feeding behaviors. But they negatively conditioned
this with potassium chloride associations, and potassium chloride causes withdrawal
of the body into the shell. Uh. Not only did
fear conditioning work the snails began to react to the
sugar by withdrawing, but physiological monitoring also found that conditioned
(39:05):
exposure to the sugar caused the heart to skip a
beat quote, suggesting physiological responses similar to fear in mammals.
So you train them to associate potassium chloride, this noxious chemical,
with the sugar, then later you just present them with sugar.
Not only do they not go for the sugar, it
makes their hearts skip a beat. Though. I do think
(39:26):
it's interesting to know potassium chloride is literally a heart
stopping poison. It's been used to cause cardiac arrest and
lethal injections. Of course, there was no potassium chloride in
the sugar once it was conditioned, but maybe that's just
a coincidence. But the idea is that been presented with
the with the sugar, then after being exposed to the
potassium chloride, there is this this moment of physiological fear
(39:50):
in response, right, the body reacts in a way similar
to mammals reacting to the werewolf mask, but this time
it's just sugar that the snail has come with training
to associate with a bad chemical. Uh So, it seems
that the majority of research on physiological correlates of invertebrate
emotions has to do with the presence of what are
(40:10):
called biogenic amines, which are thought to play a major,
if not comprehensive role in the creation and control of
emotions in the human brain, especially the hormones and neurotransmitters serotonin, dopamine,
and nora adrenaline. Now, as important as these three substances
clearly are in our emotional lives, unfortunately it is not
(40:32):
as simple as saying one is a happiness drug in
the body and one is a fear drug, etcetera. They
play complex interacting roles in everything from attention and arousal
to reward, motivation and sleep, and the manipulation of emotions
is generally not as simple as just saying like, well,
you need more of one of these things, but manipulating
(40:55):
the presence of one or more of these neurotransmitters can
have some measurable effects on emotion. For example, invertebrate nervous
systems also appear to make use of these biogenic amines
or analogs to them. For example, in bees, the hormone
octopomy and appears to play a role similar to that
of nora adrenaline and humans. And so they cite one
possible example of these physiological parallels quote Bates and and
(41:19):
colleagues in two thousand eleven assessed how systemic biogenic amine
levels changed in response to a presumed negative emotional event
hemal lymph. And remember that's like insect blood. Hamal Lymph
was collected from honey bees after simulating a predator attack
shaking bees on a vortex for sixty seconds. And this
is like the thing we talked about in the last episode,
(41:41):
where you'd shake the colony to simulate an attacked by
a honey badger. Picking up with the quote, analysis of
the hemolymph using high performance liquid chromatography or HPLC showed
that systemic levels of the biogenic amines dopamine, octopamine che
chemically similar to noor adrenaline, and so tone in all
decreased in response to bees being shaken vigorously. In humans,
(42:05):
it seems that depletion of biogenic amine serotonin, noor adrenaline,
and dopamine is responsible for features of depression in the
monamine Hypothesis of depression and also inteen Faucet and colleagues
reportedly used chemical manipulation of serotonin levels to alter anxiety
associated behaviors of crayfish, like in the plus maze scenario.
(42:28):
One last one period All in TwixT found that manipulation
of dopamine levels seemed to affect the apparent positive emotional
state of bumble bees. Remember the sugar causing the bumble
bees to have an optimistic bias. Well here quote the
optimistic behavior scene and the judgment bias test in response
to pretest sugar reward was abolished when the bees were
(42:51):
topically treated with the dopamine receptor antagonist flu finazine, and
apparently the same treatment eliminated the positive effect of retest
sugar during the simulated attack by a crab spider. So
if you do something to this insect's dopamine levels. By
by putting in this disruptor of dopamine, you somehow seem
(43:11):
to interfere with the bees ability to have an optimistic
bias in response to getting some sugar. Interesting. So, basically,
the more we reveal about sort of the underlying chemistry
of these emotional states um as as they are in
humans and as they are in these various invertebrate species,
it just reveals that, yeah, we have emotional states occurring
(43:33):
in these organisms, at least the physiological corelates of them.
Right Again, Yeah, we can't begin to get into the
subjective aspect of it, which you know, made very I
don't think it's a stretch at all to say that
whatever a crawfish is experiencing is fear, is different than
what a humans experienced in his fear. It can't it
can't contemplate the fear at the same level that that
a human can. But like the root of it, like
(43:55):
the root chemical and physic, physiological, um manifestation of that
emotion is essentially the same. Right. And I think now
we've seen maybe not conclusive, but pretty good evidence in
three different branches, not just the physiological which we were
just talking about but earlier the cognitive and in the
behavioral spheres. And I think we should emphasize again, you
(44:17):
know what you're getting at. None of these tests are perfect.
Even if all the results are robust, replicable, they hold
up over time, they still don't necessarily tell us anything
about what it's like to be a bumblebee or a crayfish.
I think there's always going to be that gap that
we are perhaps jumping with the rocket boots of anthropomorphic projection.
But for now, experiments like these are the best evidence
(44:38):
we have to try to figure out what kinds of emotions,
if any, are present in insects, crustaceans, gastropods, and all
manner of creatures without a spine. And those things we
learned could be very helpful in helping us understand how
emotions in mammals, including humans, developed over evolutionary time, because there,
you know, we we look at modern invertebrates and see
(45:01):
nervous systems. You know that their brain structure is very
similar to what we think our ancestors may have had
at certain times in history. We can learn what the
chemical mechanisms of emotional motivation states are how they came
to be humans ain't crawd ads, but crawd ads can
still teach us a lot. I think now at this point,
(45:21):
I bet one question a lot of people may have is, Okay, well,
what sorts of animals don't have emotions? Then? Like, is
there is there any level that we can say, all right,
here's the cut off point? Um. You know, it's it's
an interesting question to consider. UM. And I was poking
around and basically one thing I have to realize is
that is, like we said earlier, the quest for invertebrate
(45:43):
emotions is is not as expansive as as other areas
of emotional research, certainly in higher organisms. So there's just
a lot of data we don't have. UM. So you know,
I don't know when you get down to like single
cell organisms, I don't see. I didn't find any papers
arguing for emotional states there no, uh. And even in
(46:05):
weirdly like we think octopuses are more complex, uh, you know,
in terms of intelligence than these other than like insects
and crayfish are. But I wasn't really finding much in
the way of studying emotions and octopuses. It was mostly
in these simpler organisms. So yeah, there's clearly still lots
of ground to cover. Yeah, now, I mean, you know,
(46:27):
it's one of the I don't think anybody's actually arguing that, say,
a slime mold has emotions either. But we have discussed
in the show how a slime mold, uh, an organism
without like a central nervous system, is still able to learn,
it's still engaging in things that are are are like
problem solving. So you know, the stuff like that adds
(46:47):
uh some complexity to this question. But then another thing
we came to mind, uh plants the topic itself. I
think we'll have to wait wait for another episode, but
plants can essentially here, see, smell, and respond to stimuli,
and they are, according to a University of Missouri in
Columbia plant science professor Jack C. Schultz, essentially quote just
(47:08):
very slow animals um which uh, which I think it is.
It is hilarious. But at the same time it you know,
you you you look at say time time lapse footage
of save vines in action and flowers and uh and
so forth. They're just the movements of of of plants
(47:30):
in general. And this does have that seem to have
a ring of truth to it that this is this
is an organism that is not as still as we
uh as we may think. We touched the this briefly
and the recent Tolkien episodes, you know, the the idea
of the end, the moving tree, the tree that thinks
and reasons, um may not be as far fetched as
as some of us think. But as for emotions and plants, uh,
(47:54):
there's actually some fascinating research there as well. But that
is another story and shall be told another time time. Okay,
So hopefully we give everybody some food for thought here
about our own emotional states, what the human emotional state
is and what it isn't and then to what degree
we can perceive and attribute emotional states to other organisms,
(48:18):
even though you know, the the lowly crawfish. I mean,
I wonder if understanding the way that that anxiety might
affect bees or crawfish or something like that could in wait,
help give you a foothold in controlling your own emotions.
I mean again, this is something we we sort of
began the last episode talking about how the emotions are
(48:38):
from our brains. They are within us, but often it
can feel as if we are in them, you know,
there see, on which we're aflow and we have no
power over them, right, or their external forces like something
from out of Greek mythology, or you know, some sort
of you know, a fundamentalist um you know, Christian worldview,
angel on one shoulder, devil on the other, affecting our
(48:58):
mental states. But no, it's it's all within and it
is and it is you know, a part of the
same navigation, a reality that is taking place in all
these other organisms as well. And yeah, therefore if we
demystify it a bit, if we sort of take a
step back from it and in fact increase awareness of
what it is, then yeah, that gives us, I think,
a tremendous strength. You know, it keeps basically keeping uh,
(49:22):
keeping our our our irksome brains from deceiving ourselves about
what we are. You are that churning ocean, Yes, which
perhaps is some ambiguous information that you may either see
in a negative or a positive light, depending on your predisposition.
All right, so obviously you all have emotions, and you
(49:43):
all have various interactions with animals, be it a dog,
a cattle, horse, or a crayfish or or or a bee.
So we would love to hear from everyone out there
on the topic that we've discussed in these two episodes
of Stuff to Blow Your Mind. Hey, even if you
have some thoughts about plants, go ahead and go ahead
and let us know about those. Uh. In the meantime,
if you want to check out other episodes of Stuff
(50:04):
to Blow Your Mind, where can you find this show? Well,
you can find this show anywhere you find podcasts, wherever
that happens to be. Just make sure you rate, review,
and subscribe. Those are the acts that help us out
huge thanks as always to our excellent audio producer Seth
Nicholas Johnson. If you would like to get in touch
with feedback on this episode or any other, to suggest
a topic for the future, or just to say hi,
(50:25):
you can email us at contact dot stuff to Blow
your Mind dot com. Stuff to Blow Your Mind is
production of I Heart Radio. For more podcasts for my
heart Radio, visit the iHeart Radio app, Apple Podcasts, or
wherever you listening to your favorite shows. I Pass has
(51:01):
a fad backed by a part
Hey, welcome to Stuff to Blow Your Mind. My name
is Robert Lamb and I'm Joe McCormick, and it's Saturday.
Time to go into the vault for a classic episode
of the show. This one originally aired March seventeen, and
it's the second of our two part series about invertebrate emotions.
So we hope you enjoy and maybe fall in love
with the slug Welcome to s About to Blow your
(00:29):
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 we're back with part two of
our exploration of invertebrate emotions. In the last episode, we
talked about the paper Nautilus or the argonaut. We read
(00:49):
that great Marion more poem. We talked about what emotions
are the difficulties and studying them, and we talked about
anecdotes about people really seeing personnel, pity, character, and emotion
in octopuses, but then also scientific studies looking for certain
types of measurable cognitive effects of emotions or emotion like
(01:10):
states in invertebrates like bees. We talked about the judgment
bias test and how bees might have biases that come
about in optimistic or pessimistic ways based on how they're
quote feeling. Yeah, A big part of the conversation last
episode was I think, ultimately about stripping down emotion to
something that doesn't depend upon the subjective human experience, and
(01:33):
in doing so something that I don't want to make
it sound like we're, oh, we're just we're cutting out
all the important stuff. I think a lot of what
we're cutting out is the poetic stuff, the the the
the extra like self contemplation stuff, and getting down to
the root of what is an emotional state, how does
it affect um our behavior and our expectations, and then
(01:55):
you know, how do we see that echoed in other organisms? Right? Well,
we're cutting out yeah this by cutting out the subjective element,
We're cutting out the part that would be impossible to
study in other animals and just trying to say what
our emotional states as manifested externally. Yeah, But of course
the difficulty, as we discussed, is by taking out the
subjective aspect of it, we're taking out the part that
is closest to us and the thing that you instantly
(02:17):
think about when we even say the word emotion of course,
sweet emotion. Oh no, that song fills me with bad emotion,
did you. Oh, I don't know if I ever gotten
to do this rant before. Y'all know I hate Aerosmith.
Oh no, I don't know. Well, I think you may
have mentioned it once in passing. Yeah, even even the
early stuff. I don't know. I mean, I can be
(02:37):
that classic rock radio uncle, like you know when led
Zeppelin comes on, I'm like, yeah, I feel it, but
I don't know that something about Aerosmith just turns my
head three sixty degrees. Well, I have to admitted really
like a dream on. That's that's if I hear that
one on classic rock radio, I'll tune in and listen. Well,
I'm glad you like it. Hey, folks, this is Joe
(02:59):
from the Few. You're swooping in to alter the past.
Sorry about the audio, but I realized on listening back
to this episode that in our excitement about the topic,
we forgot to reintroduce the paper that we were talking
about in the first episode, and then we're gonna be
talking about throughout this one as well. So that paper
was by Clint J. Perry and Luigi Bachi at Donna
and it's called studying emotion and invertebrates. What has been done,
(03:23):
what can be measured, and what they can provide. It
was published in the Journal of Experimental Biology in Okay,
now back to our original conversation. Okay, But so the
last time we talked about one of the main three
branches of external ways of studying emotions and animals. We
talked about you know that they're they're perhaps cognitive effects
(03:45):
of emotions, that emotions affect how you perceive the world
and how you think. That there are behavioral tests of emotions,
that emotions affect how you act, and that there are
physiological tests of emotions that emotions affect involuntary physical reaction
in the body. And we last time we looked at cognition.
This time we're gonna look at the other two. So
the first would be behavioral tests behavioral signs of emotional states.
(04:10):
And one of the things that I think we should
first acknowledge is that I'd say, this is the primary
way that we sense emotions in other people. What do
people usually do with their bodies, especially their faces, when
they're feeling various emotions. But as the authors point out
quite helpfully, they say, quote invertebrates lack the facial musculature
(04:31):
for any real type of comparisons to be made in
this regard, so I think that the jury is in.
You can't tell if a hornet is smiling. You can't
tell if there is disgusted on the face of that crab. Yeah,
I mean, as if a crab had a face anyway. Right, Um,
but my flogging that horse again, it's not really a
horse I flog. But no, no, no no, Actually, you're right.
(04:53):
I think i'd agree the crab. I don't know crabs
pushing it. I don't know if a crab has a face. Yeah,
I mean, it definitely has the front of a head,
But that front of a head with the crab is
not really it's not used for communication. Crabs depend on
sound as well as you know. The claw waving and
overall movement displays general body language, but predominantly sound is
(05:15):
their their form of communication. The wasp for their part, uh,
they depend primarily on smell for communication. We will get
into that a little bit in the last episode with
the bees. So their communication since realm is not really
our own. Um, they exist in a in a different
realm in that regard, right, But the behavioral effects of
underlying emotional states are not limited to facial expressions alone,
(05:39):
just because that's maybe the main way we see emotions
in other people. Uh, the author's right quote. A substantial
amount of work in mammals has utilized other bodily expressions
and motor behavior in response to stimuli to assess both
valence meaning the pleasantness, and intensity meaning the level of
arousal of emotions. And I really think the horse is
(06:00):
a great example of this for a couple of reasons.
First of all, the horse is an animal that is,
that lives in close proximity to humans, that is adored
by humans. That is, that is often you know, championed
as being this next to the dog and you know
the cat, I guess it is. It is a friend
of humanity. And uh. And my wife being super into
horses and pretty knowledgeable about them, she's just told me
(06:22):
about some of this before, but I was I also
looked up a source on this for this episode How
to Read Your Horses Body Language by Jennifer Williams, PhD
for ACQUSS Magazine, and Williams points out that if a
novice were to view a skilled horse trainer in action,
they might well guess that this individual is psychic or
has some sort of mystical Cormac McCarthy in connection to
(06:45):
the soul of the horse, you know, the deep, dark,
mystical soil soul of the horse. But it's really all
about knowing how to read these other signs, the overall
body language of the horse and then these other sort
of non facial or semi facial cues. Well, yeah, I mean,
I think if you're a dog person, if you've got
a dog in your house, think about like, how finally
(07:06):
a tune you are to your dogs feelings, levels of excitement,
motivations and and quote emotional states or you know, there's
something that is analogous to these emotional states. Uh that
if somebody who had never met a dog before or
hadn't spent much time around dogs saw you interacting with
your dog, they might well think the same thing. You
must be psychic. Yeah, but no, A lot of it
(07:28):
is about picking up on all of this language, or
indeed just knowing what to look for. So in the
case of the horse, for instance, Um, your position is
very important. Is one of the apparently the first things
you tend to learn about about understanding a horse's emotional state,
so that the ears may face forward, meaning they're interested.
They may be pinned back, meaning they're angry and they're
prone to bite or act you know, aggressively slash defensively. Uh.
(07:51):
They might be turned out to the side, meaning they're relaxed.
They might be turned back but not pinned, and this
means they're listening to something behind them, and it also
means they might decide they need to turn around to
go look at it, and horses, being large animals, it's
something to be aware of. Uh. And then they also
might be rapidly swiveling, meaning that they're anxious or at
their you know, at a high level of alertness. But
(08:13):
then on top of that there's also head carriage head
maybe lowered elevated snaking. You have to consider four leg
and hind leg movement and position, muzzle activity, which this
some of this gets more in line with what you
might expect from a face, you know, like what are
the nostrils doing? Uh, you know, what what's the mouth doing,
what are they doing with their teeth? That sort of thing.
There is a certain level of like what are their
(08:35):
eyes doing? Uh? You know, to someone that doesn't really
know anything about horses, it's easy to sort of think
of the eyes as being sort of like big empty
glasses without a lot of emotion. But there is stuff
you can read into it. There's the movement of the tail,
and then there's just general whole body stuff like what
is the overall bodily tension of the animal, how is it,
(08:55):
how is it moving and uh, And you can really
take all of that and read into the emotional state
of the horse. But if you just look at you know,
what you might be tempted to call the face of
the horse, you're not necessarily going to pick up on
on all those cues you have. And I think part
of this two gets we have to think about the
human situation. So clearly humans have body language. You know,
(09:16):
there's more than just the facial communication array with human
beings totally, but we do depend on the facial communication
array a lot, and we do fixate on it to
a very large degree. But basically, what I'm trying to say,
using the horses in an example, that there are there
are there are various parts of an organism that you
can look to to to figure out what their emotional
(09:39):
state is, and it may or may not be something
that matches up with the human idea, the idea of
a face. Yes, so what would be some of these
external behaviors that we could measure in invertebrates. One of
the most obvious behavioral signs of underlying emotional states and
animals is retreat behaviors. So but you know, like in
(10:01):
fear or anxiety, animals will retreat, retracting or covering vulnerable
body parts, adopting defensive posture, and running away. These are
some of the clearest ones to look for in all
of animal behavior. And so the first example cited by
the authors here looks at exactly that. And it's actually
a study we've already mentioned on this show before. It
(10:22):
came up in our episodes titled Devour of Memories. Remember
that about about the plenaria and the and the research
about whether you could gain somebody's memories by eating their body.
Uh So in this episode that we mentioned to study
about a type of large sea slug called the California
sea hair or Aplasia californica. Uh And in that other
(10:43):
episode study came up because it demonstrated associate of learning
and classical conditioning in an invertebrate sea slug. So you
offer a sea hair some delicious shrimp extract. But in
the test group, well, the sea hair is munching on
the shrimp extract, it gets an electric shock to the
head that this painful stimulus results in not a frown,
(11:05):
of course, but measurable behaviors in the slug. It withdraws
its head, it withdraws its siphon, It inks, and it
moves away from the shrimp at extract. And sure enough,
if you train it on these associations. When simply when
the animals from the test group are simply presented with
shrimp extract, they will pull back the siphon and move away.
(11:28):
By the way, see hair and the electric shrimp extract
would be a great name for a band. Just put
that out there. I think that was a Bob Weir
side project. Wasn't ok um. But whether or not, it
makes sense to use the same word we use for
emotions and other mammals. Quote the observed behavioral responses to
conditions stimuli resemble the actions of conditioned fear in mammals. Subjectively,
(11:51):
it might not make sense to talk about fear in
a sea slug. We don't know, but it certainly behaviorally
looks like fear. It looks like the same thing we
recognize this fear in mammals or in other humans. Because
of course, nothing about the shrimp extract itself causes pain.
It couldn't be a simple stimulus response. It has to
be this association with pain, the memory of you know,
the fear caused by the memory. And a lot of
(12:13):
invertebrate studies into emotions look for signs of fear because
fear is easier to study. Presumable fear inducing stimuli are
relatively easy to create, and behavioral responses are relatively easy
to detect. There's another example that the author's site here,
which is fear research into Drosophila also known commonly as
(12:34):
fruit flies or as vinegar flies small fruit flies. UH.
This is an extremely common organism for lab research. You'll
find tons of studies UH modeling other things in complex
organisms as they appear in Drosophila. So in twif Gibson
at all studied fear and Drosophila caused by the stimulus
(12:54):
of an overhead shadow, they used a rotating opaque paddle.
I don't know if it was a ping pong paddle.
I kind of hope it was. It was some kind
of paddle that would be made to rotate in a
circle in in in a steady progression, repeat passages over
a container of these these flies that would be as say,
eating a food source or something. And the authors found
(13:17):
that multiple repetitive exposures to this overhead shadow caused the
flies to fly around more, to hop more, to freeze more,
and to fly away from a food source. And there
was evidence in this study that the passing shadow led
to a generalized internal state. The more times the shadow
passed over, the more avoidance responses happened. So it looks
(13:40):
like within the flies it wasn't just stimulus response. The
shadow passes, then you fly away. If you are repeatedly
subjected to this stress inducing stimulus, the flies appear to
enter a state where they're just they're just in a
semi permanent way agitated. They're flying around there there of
leaving the food source. It looks like they have the
(14:02):
internal state of being afraid, and the avoidance responses remained
remained more elevated. Even after the stimulus stopped. The shadow
would stop passing over, and for some time afterwards, the
flies acted more agitated, more likely to fly away from
the food source than flies with less exposure to the shadow,
and this makes it seem as if the avoidance reactions
(14:23):
were not just the direct immediate response to the shadow,
but also influenced by this internal state within the flies
nervous systems, which is similar to how fear works and
humans and other vertebrates. Something jumps out and scares you,
you have an immediate response, maybe you shriek, maybe you
pee a little, you know, maybe maybe you jump, But
then you also remain in a state you're on edge
(14:46):
for several minutes afterwards, showing these anxiety behaviors even when
the scary thing is gone or no longer represents a threat. Unfortunately,
this is a lot of how we live our lives actually, Right, Like,
there's something that kind of like startle as you, gets
you on edge, and maybe it's not even something that
would be a physical threat. Maybe it's just a conceptual threat.
You know, you get an email or a tweet or
(15:07):
anything that kind of puts you on edge, and then
you just stay that way for a good long while. Yeah, yeah,
all day generally. Yeah, what happens when you reach for
your phone first thing in the morning, right, and I
think that that's an important thing. It calls to to
attention the difference between fear and anxiety. Fear, of course,
is a response to the perception of an immediate threat,
(15:29):
a clear and present danger, and it results mostly in
escape behaviors by animals. You're trying to, you know, defend
yourself and get away. Whereas anxiety is related to fear
but slightly different. Fear is a response to the clear
and present danger. Anxiety is a response to ambiguous, imagined,
or potential threats. When there's a threat that's not necessarily
(15:52):
right in front of you, but you imagine it might
be waiting nearby, it might be around the corner. Yeah,
it's kind of lurking in the the the information sphere
around you, as opposed to being right there in front
of you. Uh. And and of course they bringing back
to the human experience, we have no shortage of Fear
is just sort of rotating around us in the information sphere.
(16:14):
And this state of anxiety actually brings us to the crawdads.
I know, we promised we'd we'd get there eventually, a
k A crayfish a k A. Mudbugs. Did you grow
up calling them mudbugs? No, this is what I've just
heard them called. Did you catch them in the creek? No?
I know I was never around them growing up, but
I have family that lives in southern Mississippi, and you
(16:35):
know they're they're all about them, uh down there. In fact,
I've been to and then this will this will be
like an image to come back to. As we discussed
their possible emotional states. I went to a Marty Groppard,
not the main Marty grap right, but I like, you know,
one leading up to it in southern Mississippi, and there
were like games where live crawfish were thrown by children,
(16:59):
like they road crawfish back and forth at each other
and then occasionally fall onto the concrete and all. And
um yeah, at the time I thought it was weird
and kind of barbaric. So man, maybe I'll feel even
more so as we discussed their their their inter emotional
states here, so it gets turned inward as well. Though.
Do you ever play the game I assume you didn't
or see people play the game where you just let
(17:19):
a crawdad pinch, you know, just like let it pinch
your nose or your finger or something. Did you do
this growing up? Uh? No, but I had friends who did.
Where was this in Tennessee? They were to carl crawdads
just in the creeks. Well, I guess there were probably
a different species, I'm not quite sure than the one
we're about to talk about, but yeah, there were some
kind of crayfish shaped organism living in the creeks freshwater creeks. Yeah, okay, yeah, yeah.
(17:44):
My main experience with them is just occasionally eating them
as an adult. Um, but that's about it. Never got
to play with them as a child. But for anyone
out there who does doesn't, it still doesn't know what
we're talking about. It's essentially a small crustacean like a
fresh a small fresh water only lobster, right, yeah, tiny lobster.
The specific uh species that's going to come up in
(18:05):
the in the research we're getting to is Procamboris clarkey.
And yes, these are the crawlfish of the famed Louisiana
crawfish boil. So I don't know if they were if
they were boiled up with some zatarans and eating after
the test there. I should also add that sometimes you'll
see crayfish in aquarium settings and they can be quite
beautiful as well. So you know, I don't think human
(18:27):
and humans humanity. Relationship with the crayfish is mostly uh,
mostly something that revolves around eating them, but sometimes you'll
see them as pets. Now, to come back to the
idea of anxiety, we were talking about the difference between
fear and anxiety. You know, we're saying fear often results
in escape behaviors. Anxiety is often thought to result in
(18:47):
conservative or defense behavior, for example, to limit openness and
to limit exploratory behavior. Animals in an anxious state are
more likely to seek out closed familiar and protect it
in environments, whereas animals in a non anxious state are
more likely to explore unfamiliar and open environments. And one
type of experiment that has been used to study anxiety
(19:10):
in animals like rats and mice and now in crayfish
is the elevated plus maze. So, Robert, had you ever
seen one of these before? I don't think I'd encountered
one of these before, and I don't remember encountering one
in a study. I've certainly never been in one. So
you imagine a simple platform in the shape of a
plus sign. You've got two arms of the plus sign
(19:32):
that are enclosed by walls, and then the other two
arms are open. They're just straight platforms without walls. And
this shows up in all kinds of studies. How an
animal moves within an elevated plus maze or EPM can
be manipulated by lots of variables that are thought to
control anxiety. The more time the animal spins in the
(19:53):
closed section enclosed by the walls, you know, sort of
protected and hidden, usually the more anxious and is thought
to be. And many animals, maybe most small animals, tend
to prefer dark, enclosed places. These are the types of
places that they are more likely to be protected from
predators in their natural environments. Like the rat in your house,
(20:15):
it likes to hide inside the walls and behind the
fridge and stuff. It doesn't like to hang out in
the middle of the floor, right like a wide open
spaces that's where a hawk can swoop down and pick
you up. That sort of thing. Right. It will only
venture out into the open spaces in order to explore
and seek rewards. It might go out there if there's
food in the middle of the floor, um, But if
(20:36):
it sees something scary, what does it do? It runs
to an enclosed space. The more an animal like a rat,
has an induced state of anxiety due to an ambiguous
or possible threat, the more it will tend to confine
itself to dark, enclosed spaces. And conversely, the less anxiety
it has, the more it will feel free to explore
open spaces. Uh. And the e p M is widely
(20:57):
used in studying animal anxiety and in the test sting
of anti anxiety medications. Now here's where the crowd ads
come in. So the elevated plus mayze has been widely
used in anxiety research like we're saying, and almost all
these studies have been on vertebrates, but since there have
been at least two studies using the plus maze test
on crayfish. Again, this is procam Boris Clarkey, and the
(21:21):
updated design used an elevated plus mayze submerged in water
with the enclosed arms shaded so that they were dark
because in their protected environments, the crayfish like dark places.
That's a natural defensive preference they have. So there were
a couple of studies. One was Fawcett at all in
fourteen and one was Bacquey casanave at all in seen
(21:45):
and They both found that if you subjected the crayfish
to frightful stimuli ahead of time, they would spend more
time in the shielded, dark, enclosed areas of the elevated
plus may so the examples were mildly painful shocks and
harassment by a larger crawfish. So like, if you take
a smaller crayfish and then subject it to a bigger
(22:06):
one doing dominance displays, the one, the little one, the
one that is being harassed, will tend to spend more
time in the enclosed area in less time exploring the
open platforms. And the authors right quote. These behavioral results
fulfill criteria normally designated for anxiety and mammals, including being innate,
being unconditioned, occurring in the absence of a stressor, and
(22:28):
expressed in a novel context. Al Right, so in this
experiment we see the evidence that a crayfish, something we
don't think of as having emotional states, really ultimately has
something very similar that to the the fear that is
experienced by a mouse or a rat, and therefore very
(22:49):
similar to what we experience. Right, So it's not just
stimulus response. I mean you could you might imagine that
an animal without emotional states could say retreat in the
immat term from something that's threatening it by going into
an enclosed space. But even afterwards it seems to remain
in this internal state where it prefers to stay in
(23:10):
the closed protected spaces and does less exploring than a
control crayfish if it has at some recent time been
threatened or harassed. It sounds like a familiar story. Yeah, yeah,
Like like I say, if we take away sort of
the the holy human qualities of fear, uh and and
look at it objectively, like this's what we're looking at here,
(23:33):
We're looking at the fear of the crawfish. Well, maybe
we should take a quick break and the when we
come back we can discuss the joy of the fire. Ant. Alright,
we're back. So the authors of this study we've been
looking at point out one shortcoming of the existing body
of research on animal emotions, and it's that it is,
as on the whole, overly focused on negative emotions. Quote.
(23:57):
It is argued that the reasons that positive and motions
have been neglected in research, or because they are few
in number, reflected even in the imbalance of English language
words for negative over positive emotions and are harder to differentiate.
The asymmetry might also stem from our understanding that natural
selection has shaped emotions more for survival than for prosperity.
(24:20):
There are many more threats than treats in our environment. Also,
they point out that if we're looking for tests mirroring
work done on humans, most psychological and clinical work in
the history of science has been focused on solving problems
rather than on studying ways in which people are doing fine,
all of which I think is probably true. I mean,
(24:40):
I think all of those reasons are valid. But despite
these limitations, it would be great to have more research
attempting to understand positive emotions or the state's analogous to
positive emotions in non human animals and invertebrates. Like, it's
just kind of a bummer and kind of limiting when
it's overwhelmingly research on fear and aversion. Yeah, that's an
interesting point about like even the the the English language
(25:04):
bias for negativity as opposed to positivity. Uh, it makes
me think of going to our our neighborhood reality the
only video rental store in the city or state video Drume.
Video Drum has a sizeable horror selection, and I love
to lose myself in it. But what is the opposite
of the horror section? There's not really one. I guess
(25:26):
what the maybe the comedies but Robert Altman section. Maybe that.
I mean even you know, any comedy, any drum, anything
that's not like straight up like a little kids cinema.
I mean, to whatever extent that exists, like anything that's
not just teletopies is going to have risk and danger
and these negative emotions that are there to at least
propel the corresponding positive ones. Yeah, I think you're exactly right,
(25:50):
And I think the point they're making is a good one.
That it's not necessarily that there's more, you know, uh,
negative emotion than positive emotion in human life, but that
for some reason we're more we're happier to let positive
emotions all kind of blend together and be the same thing.
They're all just you know, there are a million different
forms of happiness and joy, but we don't have as
(26:11):
many differentiated words for those states, you know, whereas you know,
we're we're very into getting down in the nitty gritty
of different types of ways to feel bad. Well, I
guess one of the it kind of comes back a
little bit probably to something we've discussed before, the idea
that when you're happy, if you contemplate about your happiness,
(26:31):
if you stop to consider your happiness, then it goes away.
But if you don't need to think about it too much, yeah,
you don't really have enough time to get to nuanced
in the language. Whereas a negative, a good negative emotion
will just really sit there and you can get to
know it. You can you can really uh, you know,
formalize your relationship with it. Yeah. Now, on the other hand,
(26:51):
there have been a few studies that have gone against
this trend of focusing overwhelmingly on negative emotions in these
animal studies. For example, in the last st episode, we
talked about the one cognitive tests, the judgment bias test,
that at least appeared to show the cognitive effects of
something like pleasure or happiness in the bumblebee. You remember,
it was like, if you give the bumble bee a
(27:13):
free treat, give it some free sugar, it will tend
after that to at least appear to have an optimistic
bias to interpret ambiguous information as as being something good
or approachable. The next line of research involves the behavior
and ants that some researchers think may be associated with
an internal state analogous to happiness or joy. Uh so,
(27:35):
what might the dreaded fire ant have in common with
your favorite cute puppy wagging? Butt wagging? Do tell, Do tell? Alright?
So the red imported fire ant or Solenopsis invicta, has
displayed a very interesting behavior observed by a number of researchers,
reported in a study in sixteen by Debbie Castle, christophord Liu,
(27:58):
Hun Daniels, Shiftman, and S. Bradley Vincent called a Study
on Abdominal Wagging in the fire ant Solenopsis Invicta with
Speculation on its meaning in the Journal of Bioeconomics. So,
the researchers were just watching lots of hours of video
taken from inside a fire ant nest, and from these
(28:19):
observations they started to notice a pattern of behavior where
the ants inside the nest would basically stick their butt
up in the air and wave it around. Quote they
position and move their abdomen up and down at forty
five degrees, and they called this behavior wagging. Now raising
and wiggling the abdomen has uses in other contexts for
(28:42):
fire ants. You may have seen fire ants doing this defensively.
The abdomen or back segment of the body is also
known as a gaster, which is great like Charles Dickens name,
you know, like like William Gaster uh And outside the
nest the behavior is known as gaster flagging. They'll flag.
Usually involves raising the abdomen up higher something more like
(29:03):
ninety degrees. Flagging is apparently used during foraging to disperse
venom into the air, and it's believed to deter other
insects like competitor ants from the foraging area. So you're
out trying to gather food for the colony and then
some other ants come in, you will stick your butt
up in the air and spit some venom out into
(29:23):
the air to try to drive the other ants off.
There's also some evidence that some abdominal wagging or gas
or flagging emits a sound as the gaster joint rubs
across itself, and this would be a tiny, high pitched squeak.
We're not sure what role this sound plays, but it's
possible that has a It has a role in communications,
such as calling for help when an ant is trapped
(29:45):
or when it's in trouble. However, Castle at all believe
that in their observations, the inside the nest wagging behavior
was not defensive in any way. Within the nest, they
found that the wagging emitted neither sound nor um, no squeaks,
no toxins, and the stinger was never extended during this period.
So if they're just wagging around and has nothing to
(30:08):
do with the other types of wagging that these ants
normally do, what's going on. Furthermore, they found that the
inside nest wagging happened primarily when the ants were engaged
in two activities, eating sugar or tending to the brood
in other words, taking care of the young. Well, those
are two pleasurable experiences just for humans, sure, And they
(30:30):
did not find any evidence of nestmates reacting to the wagging,
so they couldn't detect any role for communication in the wagging.
So what's it for. Well, the author's hypothesized that quote
this in nest behavior might be analogous to facial expressions
and bodily postures of hedonic pleasure in humans and other
(30:50):
mammals during pleasurable events. So that's a very interesting idea.
Perhaps a fire ant smiles by wagging its gaster in
the air. Now, we should definitely acknowledge, and the researchers
do acknowledge that this is far from proven. That there
are a few other possibilities to Maybe the wagging is
some kind of mechanical reaction in the body to certain
(31:12):
uses of the mouth parts, so that the mouth parts
would be engaged during eating or during tending to the brood.
Maybe something's happening that just happens to make their butt
wiggle in the air at the same time. So it
would help if this could be paired with other types
of tests. For example, would consuming sugar water or tending
to the brood also cause the fire ants to have
an optimistic bias in judgment bias tests? That would probably
(31:36):
strengthen the case for this wagging as a bodily expression
of something like pleasure or happiness. But I love the possibility.
Maybe the ant smiles with its But but again, this
would this would come down to a It's some physical
body language that is observable that would potentially demonstrate the
(31:56):
emotional state of the creature, right, and it would helpful
if you could pare it with other things that were
presumed to be associated with that same state. Now, another
one about positive emotions comes back to bumble bees, which
we mentioned in the last episode. Remember earlier there was
this research seeming to indicate the giving a bumblebee some
free sugar would result in an optimistic bias in these
(32:17):
cognitive tests. Another test on bumblebees looked at the effects
of sugar water on behavior after a stressful event. So,
in the wild, bumblebees are subject to ambushes by certain
sit and wait predators, such as the crab spider. Have
you ever seen a crab spider in action? I'm not well.
So they will tend to wait on a flower, uh,
(32:39):
and they'll just kind of blend in there among the
petals that they've got these wide legs, uh for a
big hug. And then when the bee lands on the
flower to try to get some nectar, the crab spider
will grab it with its legs and try to bite
down and kill it. And a lot of times in
natural encounters, the bee is briefly captured by the spider,
(33:00):
but then manages to escape. So, in a twenty sixteen experiment,
Perry at All created a simulation of a crab spider
attack by putting together a mechanism that would ambush and
trap a bumblebee for three seconds before releasing it unharmed. Now, obviously,
after a stressful brush with death like this, the bee
will take some time before it again begins to forage
(33:23):
and start landing on flowers and stuff. And what Perry
at All found was that a treat of sugar water
given before the attack would shorten the duration of this
cool down period after the spider attack. So if a
bee gets a sweet treat before a simulated spider attack,
it takes the bee less time to reinitiate landing on
(33:44):
flowers and feeding after this stressful event. Now, again, there
could be other interpretations of what's happening here. Maybe somehow
the nutrition and the sugar makes the bee physically stronger
and less vulnerable, etcetera. And maybe something like that. But
one possibility is the the pleasurable stimuli of the sugar
water puts the bee in something analogous to a better
(34:05):
mood or emotional state, making it more resilient to stressful setbacks,
which I think is something that we're probably all familiar
with ourselves. Right, you know that your emotional state is
uh dictate strongly how you will react to negative incoming events, right, Right,
The same thing that floors you one day, I'll just
kind of bounce off you another right, right, Or if
(34:26):
you've had a particularly bad day, then bad news is
going to you know, have a more negative effect on
your well being right now. The authors identify vocalizations and
sound as a possibly very fruitful behavioral avenue for future
research and invertebrate emotions, noting that Charles Starwin himself speculated
in eighteen seventy two that quote, insects might potentially communicate
(34:48):
emotions such as anger, terror, jealousy, and love through their stridulation,
you know, the great rubbing together sounds that insects make.
So what does a jealous cricket sound like? I'm not sure,
but it's easy to imagine all the various anthropomorphic interpretations.
So regarding our our ideal cartoon cricket, I'm sure. Do
(35:10):
you even remember how in the original Pinocchio, Pinocchio kills
the cricket with a hammer? What? Yeah, the cartoon or
no story? Not? No, no, not in the movie the
movie changed it made it nicer in the original story.
Jimmy cricket, Yeah, oh man, I don't remember if he's
named Jiminy cricket. I think he's just a magic cricket
and Pinocchio kills him with a hammer. I didn't even
(35:32):
know that Pinocchio is in one of his bad phases. Uh.
You know, I don't think I like Pinocchio. I don't
have a lot. I don't have a strong affinity for
the Disney version either. The only thing that I have
a strong affinity for is Jimmy crickets role in the
Mickey Christmas Carol, in which he plays what the ghost
of Christmas past? I believe, I don't. I don't know
(35:52):
if I ever seen that. You should see. It's like
thirty minutes long, and it's it's a pretty good, streamlined
adaptation of Chris was Carroll. I'm sure it's better than
the other thirty minute version of a Christmas Carol I've seen,
which is called the Christmas Carol and it's narrated by
Vincent Price. It's very bad. Man. Well, later this year,
when Christmas frows around again, I think we should do
(36:12):
an episode on a Christmas Carol. I think there's a
lot to discussed there. Okay, well, maybe we should take
a break and then when we come back we can
talk about physiological tests than Alright, we're back. So we're
entering the final phase here. We're going to be discussing
physiological tests for emotion. Right, so we've talked about cognitive tests,
(36:33):
we've talked about behavioral tests. Physiological tests for emotion uh
in people, they look for correl It's between reported emotional
states and automatic responses in the body. So, for example,
somebody jumps out at you with a werewolf mask. You're
not just gonna jump back. It's not just gonna maybe
give you a pessimistic bias. But you will also have
increased heart rate, release of stress hormones like nora ep
(36:54):
and effer and and cortisol, dilation of the pupils in
the eye. You might be a bit you know, by
just stuff. I know a lot of this is because
it's not just that you saw a werewolf. It's that
your body is preparing you to fight a werewolf or
run from a werewolf. Right, The fight or flight response
kicks in and and it entails this cascade of automatic
reactions in the body, things that you don't control behaviorally.
(37:16):
They just happen without your say so. And these physiological
responses can usually be measured objectively pretty easily, which is
very handy. However, physiological responses alone can be They can
be hard to use to identify individual emotions. For example,
if you're measuring a heart rate, heart rate might increase
in response to anxiety or to joy. The fact that
(37:38):
the heart speeds up it's beating tells you there's some
kind of arousal, but it doesn't necessarily tell you which one.
The person's heart could just be full of song, right.
So sometimes if you look at enough different physiological responses
at the same time and compare them, you can start
to zero in on specific emotions, but not always. And
(37:59):
just like it's to translate research on human facial expressions
to invertebrates, it's also hard to do so with human
physiological responses to emotions. Uh. The authors write, quote, most
of these types of measurements are quite difficult to apply
to invertebrates given their often miniature size and hard carapaces, and,
in the case of insects, an open circulatory system where
(38:20):
heart rate is not increased. But there has been some
interesting research. Nonetheless, they cite a bunch of it just
to pick out a couple of examples. Keita at all.
In two thousand eleven did research on fear conditioning, this
time in pond snails, very expressive species. Uh. They condition
the pond snails with an association between sugar water, which
(38:42):
normally you give some give some sugar water to them
and they will start feeding behaviors. But they negatively conditioned
this with potassium chloride associations, and potassium chloride causes withdrawal
of the body into the shell. Uh. Not only did
fear conditioning work the snails began to react to the
sugar by withdrawing, but physiological monitoring also found that conditioned
(39:05):
exposure to the sugar caused the heart to skip a
beat quote, suggesting physiological responses similar to fear in mammals.
So you train them to associate potassium chloride, this noxious chemical,
with the sugar, then later you just present them with sugar.
Not only do they not go for the sugar, it
makes their hearts skip a beat. Though. I do think
(39:26):
it's interesting to know potassium chloride is literally a heart
stopping poison. It's been used to cause cardiac arrest and
lethal injections. Of course, there was no potassium chloride in
the sugar once it was conditioned, but maybe that's just
a coincidence. But the idea is that been presented with
the with the sugar, then after being exposed to the
potassium chloride, there is this this moment of physiological fear
(39:50):
in response, right, the body reacts in a way similar
to mammals reacting to the werewolf mask, but this time
it's just sugar that the snail has come with training
to associate with a bad chemical. Uh So, it seems
that the majority of research on physiological correlates of invertebrate
emotions has to do with the presence of what are
(40:10):
called biogenic amines, which are thought to play a major,
if not comprehensive role in the creation and control of
emotions in the human brain, especially the hormones and neurotransmitters serotonin, dopamine,
and nora adrenaline. Now, as important as these three substances
clearly are in our emotional lives, unfortunately it is not
(40:32):
as simple as saying one is a happiness drug in
the body and one is a fear drug, etcetera. They
play complex interacting roles in everything from attention and arousal
to reward, motivation and sleep, and the manipulation of emotions
is generally not as simple as just saying like, well,
you need more of one of these things, but manipulating
(40:55):
the presence of one or more of these neurotransmitters can
have some measurable effects on emotion. For example, invertebrate nervous
systems also appear to make use of these biogenic amines
or analogs to them. For example, in bees, the hormone
octopomy and appears to play a role similar to that
of nora adrenaline and humans. And so they cite one
possible example of these physiological parallels quote Bates and and
(41:19):
colleagues in two thousand eleven assessed how systemic biogenic amine
levels changed in response to a presumed negative emotional event
hemal lymph. And remember that's like insect blood. Hamal Lymph
was collected from honey bees after simulating a predator attack
shaking bees on a vortex for sixty seconds. And this
is like the thing we talked about in the last episode,
(41:41):
where you'd shake the colony to simulate an attacked by
a honey badger. Picking up with the quote, analysis of
the hemolymph using high performance liquid chromatography or HPLC showed
that systemic levels of the biogenic amines dopamine, octopamine che
chemically similar to noor adrenaline, and so tone in all
decreased in response to bees being shaken vigorously. In humans,
(42:05):
it seems that depletion of biogenic amine serotonin, noor adrenaline,
and dopamine is responsible for features of depression in the
monamine Hypothesis of depression and also inteen Faucet and colleagues
reportedly used chemical manipulation of serotonin levels to alter anxiety
associated behaviors of crayfish, like in the plus maze scenario.
(42:28):
One last one period All in TwixT found that manipulation
of dopamine levels seemed to affect the apparent positive emotional
state of bumble bees. Remember the sugar causing the bumble
bees to have an optimistic bias. Well here quote the
optimistic behavior scene and the judgment bias test in response
to pretest sugar reward was abolished when the bees were
(42:51):
topically treated with the dopamine receptor antagonist flu finazine, and
apparently the same treatment eliminated the positive effect of retest
sugar during the simulated attack by a crab spider. So
if you do something to this insect's dopamine levels. By
by putting in this disruptor of dopamine, you somehow seem
(43:11):
to interfere with the bees ability to have an optimistic
bias in response to getting some sugar. Interesting. So, basically,
the more we reveal about sort of the underlying chemistry
of these emotional states um as as they are in
humans and as they are in these various invertebrate species,
it just reveals that, yeah, we have emotional states occurring
(43:33):
in these organisms, at least the physiological corelates of them.
Right Again, Yeah, we can't begin to get into the
subjective aspect of it, which you know, made very I
don't think it's a stretch at all to say that
whatever a crawfish is experiencing is fear, is different than
what a humans experienced in his fear. It can't it
can't contemplate the fear at the same level that that
a human can. But like the root of it, like
(43:55):
the root chemical and physic, physiological, um manifestation of that
emotion is essentially the same. Right. And I think now
we've seen maybe not conclusive, but pretty good evidence in
three different branches, not just the physiological which we were
just talking about but earlier the cognitive and in the
behavioral spheres. And I think we should emphasize again, you
(44:17):
know what you're getting at. None of these tests are perfect.
Even if all the results are robust, replicable, they hold
up over time, they still don't necessarily tell us anything
about what it's like to be a bumblebee or a crayfish.
I think there's always going to be that gap that
we are perhaps jumping with the rocket boots of anthropomorphic projection.
But for now, experiments like these are the best evidence
(44:38):
we have to try to figure out what kinds of emotions,
if any, are present in insects, crustaceans, gastropods, and all
manner of creatures without a spine. And those things we
learned could be very helpful in helping us understand how
emotions in mammals, including humans, developed over evolutionary time, because there,
you know, we we look at modern invertebrates and see
(45:01):
nervous systems. You know that their brain structure is very
similar to what we think our ancestors may have had
at certain times in history. We can learn what the
chemical mechanisms of emotional motivation states are how they came
to be humans ain't crawd ads, but crawd ads can
still teach us a lot. I think now at this point,
(45:21):
I bet one question a lot of people may have is, Okay, well,
what sorts of animals don't have emotions? Then? Like, is
there is there any level that we can say, all right,
here's the cut off point? Um. You know, it's it's
an interesting question to consider. UM. And I was poking
around and basically one thing I have to realize is
that is, like we said earlier, the quest for invertebrate
(45:43):
emotions is is not as expansive as as other areas
of emotional research, certainly in higher organisms. So there's just
a lot of data we don't have. UM. So you know,
I don't know when you get down to like single
cell organisms, I don't see. I didn't find any papers
arguing for emotional states there no, uh. And even in
(46:05):
weirdly like we think octopuses are more complex, uh, you know,
in terms of intelligence than these other than like insects
and crayfish are. But I wasn't really finding much in
the way of studying emotions and octopuses. It was mostly
in these simpler organisms. So yeah, there's clearly still lots
of ground to cover. Yeah, now, I mean, you know,
(46:27):
it's one of the I don't think anybody's actually arguing that, say,
a slime mold has emotions either. But we have discussed
in the show how a slime mold, uh, an organism
without like a central nervous system, is still able to learn,
it's still engaging in things that are are are like
problem solving. So you know, the stuff like that adds
(46:47):
uh some complexity to this question. But then another thing
we came to mind, uh plants the topic itself. I
think we'll have to wait wait for another episode, but
plants can essentially here, see, smell, and respond to stimuli,
and they are, according to a University of Missouri in
Columbia plant science professor Jack C. Schultz, essentially quote just
(47:08):
very slow animals um which uh, which I think it is.
It is hilarious. But at the same time it you know,
you you you look at say time time lapse footage
of save vines in action and flowers and uh and
so forth. They're just the movements of of of plants
(47:30):
in general. And this does have that seem to have
a ring of truth to it that this is this
is an organism that is not as still as we
uh as we may think. We touched the this briefly
and the recent Tolkien episodes, you know, the the idea
of the end, the moving tree, the tree that thinks
and reasons, um may not be as far fetched as
as some of us think. But as for emotions and plants, uh,
(47:54):
there's actually some fascinating research there as well. But that
is another story and shall be told another time time. Okay,
So hopefully we give everybody some food for thought here
about our own emotional states, what the human emotional state
is and what it isn't and then to what degree
we can perceive and attribute emotional states to other organisms,
(48:18):
even though you know, the the lowly crawfish. I mean,
I wonder if understanding the way that that anxiety might
affect bees or crawfish or something like that could in wait,
help give you a foothold in controlling your own emotions.
I mean again, this is something we we sort of
began the last episode talking about how the emotions are
(48:38):
from our brains. They are within us, but often it
can feel as if we are in them, you know,
there see, on which we're aflow and we have no
power over them, right, or their external forces like something
from out of Greek mythology, or you know, some sort
of you know, a fundamentalist um you know, Christian worldview,
angel on one shoulder, devil on the other, affecting our
(48:58):
mental states. But no, it's it's all within and it
is and it is you know, a part of the
same navigation, a reality that is taking place in all
these other organisms as well. And yeah, therefore if we
demystify it a bit, if we sort of take a
step back from it and in fact increase awareness of
what it is, then yeah, that gives us, I think,
a tremendous strength. You know, it keeps basically keeping uh,
(49:22):
keeping our our our irksome brains from deceiving ourselves about
what we are. You are that churning ocean, Yes, which
perhaps is some ambiguous information that you may either see
in a negative or a positive light, depending on your predisposition.
All right, so obviously you all have emotions, and you
(49:43):
all have various interactions with animals, be it a dog,
a cattle, horse, or a crayfish or or or a bee.
So we would love to hear from everyone out there
on the topic that we've discussed in these two episodes
of Stuff to Blow Your Mind. Hey, even if you
have some thoughts about plants, go ahead and go ahead
and let us know about those. Uh. In the meantime,
if you want to check out other episodes of Stuff
(50:04):
to Blow Your Mind, where can you find this show? Well,
you can find this show anywhere you find podcasts, wherever
that happens to be. Just make sure you rate, review,
and subscribe. Those are the acts that help us out
huge thanks as always to our excellent audio producer Seth
Nicholas Johnson. If you would like to get in touch
with feedback on this episode or any other, to suggest
a topic for the future, or just to say hi,
(50:25):
you can email us at contact dot stuff to Blow
your Mind dot com. Stuff to Blow Your Mind is
production of I Heart Radio. For more podcasts for my
heart Radio, visit the iHeart Radio app, Apple Podcasts, or
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