Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Hey, welcome to Stuff to Blow Your Mind. My name is Robert Lamb.
And I'm Joe McCormick, and we're back with part three in our series on the theme of being upside down. In part one of this series, we talked about a scene in Dante's Inferno in which the world suddenly seems to be upside down while the poet is crawling down the body of Satan, and we talked about how different cosmological models apply to that scene. After that, we talked about adaptations to upside down living in mammalian biology, particularly
in bats and tree slots. And then in part two, we talked about inverted vampires and other beasts and monsters of folklore, things that are said to hang from the
ceiling or dwell upon the ceiling. And then we talked about the physiology and psychology of spaceflight and how in microgravity astronauts sometimes they're subject to a number of cognitive and perceptual illusions that can make them suddenly feel like they're hanging upside down, or can cause the astronauts' subjective sense of up and down to switch places, and so we are back today to talk about more.
Yeah, and one place I want to start out with here is this kind of goes back to something we were talking about. I think maybe in the first episode. We're talking about how sometimes the idea of an upside down world is not necessarily a bad thing. You know, It's not necessarily the Stranger Things model where the upside down is a nightmare, shadow realm, or you know, some sort of illogical world that is ruled by chaos. Turning
things on their head can of course reveal truth. That's how we use the phrase, and it's actually one of the key ideas bound up in the Tarot card, the Hangedvan.
I think most of you have probably seen some version of this, even if you're not familiar with taro He's He is in general revealed as an individual who is of course hanging upside down one leg by one leg, with the other leg crossed behind him, like he's doing an inverted yoga pose of some sort, but hanging from like the branch of a tree or some sort of a cross like structure, hands behind the back. But generally
he is not depicted as being in distress. Most depictions of the hanged Man have kind of a voluntary feel to them, and the idea I'm to understand within the Tara tradition is that he is seeing the world from a new angle.
That's not what I would have assumed based on the name the hang demand sounds like a character being portrayed in a kind of execution or crucifixion or something. But the idea here is more that this is a figure assuming a pose or assuming a new perspective.
Yeah. Yeah, some more things going on with other tarot cards as well, where what it might seem to be about is not the full story, and then you have interactions and so forth. But you know, there's also some connection here to the idea of the inverted cross, which is often today popularly employed as an unholy symbol particular bands. Yeah, metal bands and the sort of the sort of horror movies that you and I navigate to and sometimes discuss in weird house cinema and thinking about like a lacarda
and so forth. So you know, that's what I think of when we think about an inverted cross. But of course, traditionally within Catholic tradition, this is also the cross of Saint Peter, who, according to tradition asked to be crucified upside down because he felt unworthy to die in the normal position, the way that Christ died. So it's bound up. The symbol is bound up with ideas of humility. Now we can't be completely certain about the historic Peter here.
You know, this might just be a story with him ordering off the menu when it comes to this crucifixion. But we do have passing references to inverted crucifixions or perhaps to inverted crucifixions by such first century historians as Seneca the Younger and Flavious Josephus, to suggest that the acts were sometimes committed in this fashion and in other fashions. Now there's no real archaeological evidence, but then again, archaeological
evidence for crucifixion is extremely rare. You know, just think about the elements involved here. And there were also, to understand, no manuals on how to do it, So it's not like there was a laminated card that crucifixion. Roman crucifixion grunts referred to and decided how they were going to torture people to death. There was, you know, it seems to be kind of like a traditional way to do it. And then sometimes they did other things out of their you know, cruelty and horror.
Yeah, that is an interesting thing. I've come across this historical fact before that while there are tons of references to crucifixion in ancient literature and stuff people were writing during the Roman Empire, there's no like canonical source from Roman authorities on how you did it or what it is. Instead, it's just something that people are writing about, assuming everybody else already knows exactly what they're talking about.
Yeah, yeah, And it can be easy to assume this as well. If you again, if you grow up in in certain you know, church environments where a lot of emphasis is placed on the the you know, gritty specifics of crucifixion, you might think, oh, we got it all figured out, but there are you know, a number of uh, there are a number of questions that still remain regarding what was done and indeed, like exactly how people would
die under these circumstances. I will admit I did not have a strong enough stomach to really go any further in that direction for this episode, But there are plenty of papers out there that discuss these various ideas. But I just didn't have the stomach for it myself.
Well, I don't want to go into too much detail either, but I'll just say generally, outside of Roman Crucifixion, the possible instances of upside down Roman Crucifixion, there are some other cases in world history of torture methods that involve being put upside down.
Yeah.
I'm thinking about some Japanese examples that I know of.
Yeah. Yeah, and again I didn't have the stomach to do and all that, but they exist. There's a whole world of that if anyone is interested. The next thing that I want to talk about concerns the antipodes, or well antipode. The singular is antipode, the plural is antipothies. Yeah. So every position on our planet has an antipode. That's a position on the exact other side of the globe. So if you could tunnel from one point to another, you could travel from say Madrid, Spain to Weber, New Zealand,
or from Formosa, Argentina to tan and Taiwan. A lot of notable locations on our planet do not have an antipode. On dry land, you know, it would just if you were to tunnel straight through it would spit you out in the middle of a body of water, you know, probably in the ocean. But these are a few key surface to surface examples.
I don't know, but i'd imagine our antipode is somewhere in the Pacific Ocean.
I think, so. Yeah. I was looking around at a few and I was like, oh, well, there's not one there. Well, there's not one there. And then I was like, okay, what are what are the main ones that people point to? And generally it's you know, tunneling from you know, somewhere in Europe to somewhere Australia and New Zealand. We actually heard from a listener about this, reminding us that that Total Recall remake that came out several years ago involves a plot line about some sort of a crazy elevator
that go straight through the center of the planet. I guess it lines up a little bit with the Dante thing We're just got thing previously.
Several years ago on that Total Recall remake. I think that was like twelve years ago, now, wasn't it.
Yeah, probably that's the way it goes. I still feel like it just came out, but it's you know, it's a classic film.
Now Time, gotcha?
Yeah yeah, Time treats everyone like fool. All right, well, okay, what does all this mean? What means that you could have a person in Madrid and that person in weber Is on the other side of the globe is upside down from the Spanish perspective and vice versa. Of course, you know it's it's feet to feet And indeed, the word antipode comes from the Greek antipotis, which means with feet opposite.
Mmmm. Oh yeah, oposing feet. That that is interesting, and you know that fact actually connects to one thing I was reading about, which is the the upside downness of astronomical references depending on which hemisphere of the Earth you're in.
So maybe people don't think about this very often, but if if you're in the northern hemisphere, you know, the moon looks a certain way to you, but if you go to the southern hemisphere, the moon will now be upside down from your familiar reference point because now you're on the opposite side of the sphere looking up at it.
Oh wow, I wonder if it affects like wherewolf transformations like in Australia, wherewolves transform from the feet up or something I don't know instead of mouth first.
Interesting, but you can imagine that it is save for ancient writers who did. By the way, you know, there's a common misconception that, like, you know, everybody used to think the Earth was flat. In history. There was some flat Earth consciousness, but there was also a lot of
round Earth consciousness. So like ancient writers think understanding that the geometry of the earth roughly understanding that it must be round, and thinking about beings on the opposite sides with their feet facing our feet and their heads going in the opposite direct action. What kinds of beings must those be?
Yeah, and it's interesting to look at this. This generally boils up in discussion of like the monstrous races, the monstrous people's the ideas that, yeah, they're humans all over the world, but man, they take some weird forms. They might have like a mouth in their stomach. They might hop around on one foot and then laid back and position that foot over their head to provide shade, that
sort of thing, you know. And a big part of this is that you would have writers such as Roman historian Plenty the Elder, who've talked about many times in the show with someone like Plenty. You know, Plenty was I'm to understand more of an empiricist concerning things closer to Rome and things that he was able to witness
first hand in his own personal travels. But he is in the Natural History attempting to write about the known world, and so he has to depend on a lot of far flung and sometimes fringe accounts from things much farther out from secondhand and then third hand sources, you know, from sailors and that traveled far or historians were reporting as well on something that they receive second or third hand.
Yeah, and so you get interesting things when you read Pliny's Natural History. Again, this is a first century Roman source that's trying to create a kind of encyclopedia of all knowledge at the time, and you get this weird mix of like, oh, wow, you know, they they understood this. They actually it's kind of surprising that they would have certain understandings and knowledge that are to some degree correct
much earlier than you might think people did. And then on the other hand, you will get bizarre, fantastical accounts that are obvious and like scientific explanations that are obviously wrong.
So here's an example of the outrageous. That is obviously wrong concerning an antipode. And yeah, so there's essentially there's a mythical race of people connected with the idea they referred to, I believe as the Abaraman, which Plenty writes of here He discusses this and other opposite peoples in book seven of the Natural History. I'm going to read
a quote. But beyond the other Scythian Cannibals, in a certain large valley of the Immavas Mountain, there is a region called Aberaman, where are some people dwelling in forests who have their feet turned backward behind their legs, who run extremely fast and range abroad over the country with
the wild animals. It is stated by Baton, Alexander the Great's route surveyor on his journeys, that these men are unable to breathe in another climate, and that consequently none of them could be brought to the neighboring kings, or
had ever been brought to Alexander. According to Isaginus of Nicea, the former cannibal tribes whom we stated to exist to the north ten days journey beyond the river bor Sithonians sorry Bori Scynthienes drink out of human skulls and use the scalps with the hair on as napkins hung around their necks. The same authority states that certain people in Albania are born with keen gray eyes and are bald from childhood, and that they see better by night than in the daytime.
Now, wait a minute, are any of these peoples said by plenty to be Antipodean or these are just generally like descriptions of peoples that are probably way off base.
Yeah, mostly this is just people far away, essentially on the other side of the earth, are remarkably different, like to the point where they might not be able to breathe the same air. Or yeah, they see better at night than in the day. You know, obviously we know that this is not the case with human beings. There are differences with you know, among different peoples in different parts of the world, but they're not this pronounced, not
at all. And there are some other creatures and monstrous races that pop up in other medieval bestiaries, such as the Newly I think they're also sometimes described as being an antipode race. But yeah, I think, you know, I think that you know, despite all of this being, you know,
being quite incorrect. You can imagine that there's a pervasive idea here from antiquity through medieval bestiaries, that humans that lived on the other side of the planet or sufficiently beyond our horizon might be fundamentally different in key biological ways, almost like their aliens from an entirely different planetary ecosystem.
At the same time, it's worth noting again that Plenty very much believed that the entirety of the round Earth was populated with people, and so like that's the deeper truth here, Like he's getting a lot of things wrong, but he's also saying here and elsewhere that the world is round and there are people all over it. And he discusses this in the section chapter sixty five that is titled whether there be antipodes or antipodies? On this he writes, quote, on this point there is a great
contest between the learned and the vulgar. We may maintain the learned that there are men dispersed over every part of the Earth, and they stand with their feet turned toward each other, that the vault of the heavens appears alike to all of them, and that they all of them appear to tread equally on the middle of the Earth. If anyone should ask why those situated opposite to us do not fall, we directly ask in return whether those on the opposite side do not wonder that we do
not fall. But I may make a remark that will appear plausible even to the most unlearned, that if the Earth were of the figure of an unequal globe like this, like the seed of a pine, still it may be inhabited in every part. Hmm.
Okay, I don't want to overstep, because I don't know for sure here, but I would guess then that Plenty has basically is. Obviously this is going to be incorrect in big ways that come into focus when you think about, like the other planets in the stuffs. But that he can have basically the right idea about Earth's gravity even without having an idea of gravity, just the idea that all around the surface of the Earth everything would be
attracted toward the center. And he could have that idea, possibly based on the same kind of Aristotelian model of heaviness and lightness that Dante was probably using a thousand years later, more than you know, twelve hundred thirteen hundred years later.
Yeah. Yeah, So I think it's interesting to sort of focus in on this because, yeah, we sometimes we give Plenty up a bit of a hard time based on some of the more outrageous things in the natural history. Though we often highlight what Plenty has to say in that it shows how much was known at the time. And to be clear, he was one of the most learned men of his day and a titan of knowledge, and that's why we keep referring back to him. You know.
It's whatever Plenty had to say about something or didn't have to say about something informs us about just what was known during this time period, you know, during the first century.
See, yeah, gives you a good snapshot of what generally educated romans on a particular subject probably thought.
Yeah. Now, the the idea of of of of there being an antipode for every point and for there being
people on the other side of the earth. Again, I think on the whole, you know, this was considered settled among most of the learned, but you at least, you know, a couple of centuries after Plenty's time, you did have some folks who were a little bit more grumpy about the concept and uh and and disagreed with it, and even found the idea of people on the other side of the earth of as being a clear counter to the notion of a spherical earth. So probably the most
outrageous example of this is like Tensious Uh. He was a later early Christian author and advisor to Roman emperor Constantine the First. He lived two fifty through three twenty five CE. To put that in comparison to plenty live
like twenty three to seventy nine. See so anyway, this author, this later Christian author, in his work Divine Institutes Rites, Is there anyone so foolish as to believe that there are people living on the other side of the earth with their heels upward and their heads hanging down, Or that things that lie flat with us hangs suspend it there, that crops and trees grow downward, that rain and snow and hail fall upwards upon the earth.
Wait a minute, I can't tell which way this is going. Is this mocking people who don't understand that gravity would be attracted the opposite way on the other side of the earth, or mocking just the belief in people and things on the opposite side of the Earth.
He's basically taking a shot at the understanding of the world that Plenty really represents. So yeah, he was a pretty famous attachs was a pretty famous critic of the notion of around earth at the time, and though his was not the predominant way of thinking, even certainly among intellectuals.
So the notion of around earth had again been settled science essentially for centuries, as mentioned by Plenty, but the secular world was sold on a spherical Earth, though the issue remained a sort of nuisance discussion in the church. Like at times there were people in the Christian Church were like, can we maybe just shut up about this because this really has nothing to do with salvation or anything. It's just a senseless argument that probably makes people look stupid. Yeah.
Yeah. And by the way, if you're wondering, like, wait, how did people in the ancient world know that the Earth was round before they had, say, traveled all the way around it, it circumnavigated the globe. There are all kinds of experiments you can do and even just observations you can make that inform you that the Earth is round. You are being critical and you're scrutinizing the idea. You can think about simple things like ships disappearing over the
horizon as they travel farther and farther away. That's one pretty clear indication that, over long enough distances, the surface of the Earth is curved. But then there are also even going back into antiquity geometry experiments, you can do with say the angle of a shadow cast by a sun dial, and you can measure those angles at the same time of day at different latitudes and notice that there are differences, and that gives you indications that wait
a minute, the surface of the Earth is curved. And then if you extrapolate from the degree of that curve, you can see that actually we're living on a ball.
Yeah, And so as bal dwellers that we are, there are those who live right side up and those who live upside down. And at the same time, nobody is right side up and nobody is upside down.
It's true.
So I want to turn now to the realm of optics, and I think this is pretty much where we're going to stay for the duration of this episode. So here here is something that we take for granted, Okay, a basic statement that will probably feel true to most of you at least until you begin to analyze it, and that is we perceive the world right side up.
Yeah, that seems right up, looks up down, looks down right.
But what if, to borrow a comparison from David Eagleman, previous guest on the show and also fellow podcaster, what if we were to flip our eyes upside down, you know, like mister potato head style. What if we took them out, flipped him upside down, stuck him back in? What would happen?
So here, we're not considering putting them in the slot where the ears go or where the mouth goes. We're just talking about flipping the eye, just.
Flipping the eyes. Okay, Now, for starters, we should point out that this would be quite difficult to pull off in reality because you can't just say, pull the eye out, twisted around and put it back in without severely damaging the bundled optic nerve, which would cause blindness Surgically. You'd also have to contend with these six extra ocular muscles
surrounding the eye. There's a lot of stuff holding stuff in place, so you know, beyond what you might have seen in a mad magazine or something with somebody's eyeball hanging out on, you know, on a single thread. There's a lot of stuff in there, and it's very delicate if you start messing with it.
Actually, in the very next weird House Cinema movie we're going to be doing, there is a pretty pretty awesome cyborg cyborg eyeball removal and maintenance scene.
Oh well, well, now cyborg's can do it. They're different. Yeah, But as a side note, there is I was looking into this. There is actually a procedure called macular translocation by which retina is detached and shifted away from less healthy eye tissue, and then the extra ocular muscles are also adjusted to prevent a perceived tilt in vision. So there is something to that. But of course we don't have to dream up mad science surgeries to flip the vision of a human being. We don't actually have to
take the mister Potato eyes out, flip them and reinsert them. Instead, we can achieve this optically or visually. Ahead of the eye. Don't flip the receptors, flip the input, Flip the incoming media.
Okay, yeah, so you flip the image of the world before it hits the eyes.
Right, and so In this we turn to a particular American psychologist by the name of George M. Stratton and his amazing upside down goggles.
This is a famous experiment in the history of vision studies, and it's really interesting, I think.
Yeah, absolutely so. He lived eighteen sixty five through nineteen fifty seven, and around eighteen ninety six he set out to study the way that we perceive the right side up world. Because here's the mind blowing thing that Stratton knew very well and I think was probably popping into a number of your minds as you were contemplating whether we see a right side up world, and that is that we don't exactly see the right side up world
at all. If you think back to our episode of stuff to blow your mind on the Camera Obscura, which you can find in the archive wherever you get the audio version of this podcast, or any or if you think on any experience you have with these optical devices, because you can find Camera Obscura is set up at various museums and events, but light passes through a small aperture of a dark chamber and projects a scene from the outside world a projection, but the resulting image is
inverted upside down and reversed left to right. The term camera obscura, by the way, was coined by Johannes ke Bler in sixteen oh four, and he made the connection that our eye works much the same way with an image of the outside world inverted and reversed on the retina of the eye. The camera obscura and the human eye share the same fundamentals of optics here. But yeah, the what enters our eye is then it placed on the retina upside down.
But the cool thing is that that's okay because it's not the retina that sees, it's the brain that sees.
Absolutely, that's the amazing thing here. Our eyes receive an upside down version of the right side up world, and then the brain flips it without our realizing it. And I think this alone is pretty amazing.
Absolutely, yes, especially the fact that you don't have to think about doing it. You're not conscious of this flipping. The world just looks right to you.
Yeah, It's like it's like our brain is a plumber, and we have a toilet set up to flush with hot water, and then the plumber sneaks in and re and does it, and it adds an additional twist around to make sure that our toilet flushes with cold water. I don't know, this is a terrible comparison, but at
any rate, it's amazing what's happening here. So, coming back to Georgia M. Stratton, he wanted to know how we'd react, how our brains would deal with it if, via special goggles, we received a pre flipped vision of the world which then gets flipped right side up in our retinas and then flipped upside down once more via the brain. His theory was that the brain didn't really need an upside down retinal image and that it could make do with whatever it had.
Okay, so the idea is where these goggles that flip the image of the world upside down before it reaches your eyes, and figure out how does how do the eyes and the brain react to this?
Right, So this is what happened. Stratton experimented on himself wearing a special glass over his right eye, and he covered his left eye with an eye patch, and then he wore like a blindfold or two eye patches when he slept at night. So via this special goggle, he perceived an upside down world that was initially highly disorienting because the brain, to be clear, the brain didn't do anything with this information right away. Is just highly disorienting.
It's like seeing the world upside down through a crazy goggle strapped to your eye. As you can imagine, it was a lot. But by around day three things begin to even out and to be clear. And this is something that has to be driven home regarding this and other experiments using this sort of thing. It's not that the brain ends up flipping the image again, because it does not. It's not like, oh, by day three I just saw everything right side up again. No, but he
was able to. He found himself adapting to this inverted feed and was able to effectively move through environment again, you know, interact with things I believe. In this or other experiments, the users have been able to read again
that sort of thing. And then upon taking the goggles off, there's another period of readjustment which is interesting to think about, Like your brain has adapted to an upside to the upside down feed, and then when it gets the right side up feet again, you again have to sort of recombobulate yourself. He wrote. Initially all the images were inverted. Things were seen in one way and thought about it
in a different way because of memory and past experience. However, with practice, the subject and he's preferring to himself here, learned to adapt to the new visual field. On removal of the glasses, normal vision was restored. Concluded that difficulty in seeing things upright due to upright retinal images is
due to previous experience. And so this brings me back to the true example of the mister potato head that David Eagleman brought up that he's discussed on his most recent appearance on our show a few years back, and that is this idea that our brain will make use of whatever sensory information is plugged into it, mister potato head style. So it might be site, It might be smell, It might be taste. It might be something entirely new, such as like stock information or some you know, heightened
awareness of electromagnetism. It might be again to come back to the specifics here, it might be vision, but that is flipped. It might be say, smell that is different like I don't know if you were somehow able to you know, put the plug the nose of a dog onto us and gift us with like the scent abilities of a dog, that sort of thing. The brain would just make use of it. It would stitch together an
understanding of the outside world that we can use. If the world is flipped to the upside down, the brain adjusts.
This reminds me of what we talked about in the last episode actually with astronauts in microgravity. You know, when you arrive in microgravity, a lot of astronauts are going to have problems related to the brain continuing to try to establish a subjective vertical where the kind of information that it's normally getting from the vestibular system to supply that is not present, or the vestibular system is just being you know, stimulated to the point of haywireness, Like
it's getting confusing information and that's conflicting with visual information. So it causes all these problems initial but it doesn't stay, or at least for most astronauts, does not stay like that forever. There is an adjustment period, and then eventually the brain starts to get used to the new environment and adapt essentially to the idea that I now live in a place where there's no necessary up and down.
Yeah. Yeah, So there have been some other studies involving goggles like this or goggles that carry out some more functions.
There is the Ensbruk goggle experiment of the fifties and sixties, carried out by Austrian psychologist Theodore Heersman who lived eighteen eighty three through nineteen sixty one and Ivo Kohler who lived nineteen fifteen through nineteen eighty five, involving prism equipped goggles, colored goggles, and other designs that distorted perception in one way or another, including flipping things upside down, but also stuff like making the wear see only through the back
of their head via a retroscope, and so you know, they were really sort of getting into the nitty gritty of well, what if we did this, what if we
did this? And these experiments were again more focused on particular effects, and they often lasted for extended periods of time, like they would have subjects wearing these things for weeks, and you know, ultimately these various studies were further revealed the power of neuroplasticity in the brain when it comes to visual sensory input and regarding the upside down world.
These experiments also found that people adapted after a period of days psychologist Hubert Dolzel also conducted a rigorous long term study published in the book Living in a World Transformed in eighty two, and he found that while the upside down visual sensations never fully disappeared again, the world still looks flipped and your brain does not flip things back for you said that the appropriateceptive since the internal
map of where your limbs are it completely reorients. And then it's worth noting that fMRI assisted studies have also shed additional light on all of this, and the basic experimental findings seem to have remained the same. Subjects adapt to move and even read, but they don't experience a
true reversal. Things remain flipped. But i F MRI has revealed increased activity in the parietal cortex responsible for spatial processing and the motor And basically the idea here is that motor response seems to essentially be corrected to work
with the new data. So you know, to think in terms of like you know, sci fi, if aliens strapped weird goggles to our head or some sort of bizarre you know, mutagen from another world suddenly flipped all of our visions and made us see like this, it would be greatly disorienting, but we would all adapt within a matter of days and weeks to this new way of seeing and moving through the world, and it would just become. It would just become how it is.
Yeah, totally. Now, we might not all adapt at the same to the same degree or at the same rate, right, I don't know this actually, but for some reason, I would guess kids would probably adapt easier than older than older adults, and that I.
Don't recall it being specifically pointed out, but in general, we know that neuroplasticity is higher in younger humans, so that would make sense.
So yeah, I don't know that, just speculating on my part, but generally there would be a pattern of adaptation, even to things that you just wouldn't imagine that we could get used to. We can't. Okay, we've already been to hell once in this series. You want to go to hell again?
Sure? Why not? So?
I want to explore a different topic in upside down perception, specifically in how our brains process faces when they're upside down. This is a subject that I think is both funny and mysterious, fascinating and mysterious. It is known as the Thatcher effect or the Thatcher illusion, so named because it was first demonstrated with photos of the at the time of this paper newly elected British Prime Minister, Margaret Thatcher,
so this was the year nineteen eighty. But the effect, to be clear, is in no way specially related to Margaret Thatcher or to the appearance of her face. It's about how we perceive general human faces under strange circumstances. So this is one where it really benefits to see this for yourself. If you were able to look up imagery right now, you can understand the effect immediately by doing a search for Thatcher illusion, or if you go to one of the web pages that people have set
up to demonstrate it. I found one at Thatcher effect dot com.
But it is worth noting that it's gonna make more sense to you and be more effective. It is if it's a face you're familiar with, then Margaret Thatcher obviously a pretty famous international figure, but also one that people don't see every day in today's media environment, so you might be better off looking at some other celebrity or something.
People do this with other celebrities as well. In fact, I've got some in the outline for you to look at here rob In fact, for our video viewers on Netflix, could we just briefly throw up an image of the Thatcher effect to demonstrate Ah, so do explain what it is here. Imagine you take a photo of a face, any face, especially a smiling face. So I'm personally going to be thinking about Christopher Lambert here, christof Lambert doing like a big you know, grinning Raiden and Mortal Kombat
the movie, that kind of thing. So you take a pritted out photo of face and carefully you use a razor to cut out the mouth, like cut out a little rectangle around the mouth, and cut out the eyes, and then keeping the picture otherwise the same, you flip just the mouth and the eyes upside down. You leave them where the mouth and the eyes go, but you invert them. Okay, so now you've got regular face upside
down mouth, upside down eyes. The magnitude of the effect can vary, but on average this tends to create a grotesque, hilarious image that is immediately recognizable as absolutely cursed. And there are differences depending on like on a facial expression is a big thing. Like I think a very flat closed mouth makes the effect less noticeable, but especially when there's like a smile or something, this effect is not subtle. It looks like something from the pit of hell that
has come out to suck your soul. And based on looking at a lot of these, I think it is the big smile, especially that inevitably creates great terror and anguish. So I've got some more examples for you to look at in the outline. Here rob one that actually doesn't have a big toothy smile but does still look pretty cursed. Is an image that was going around of Adele with thatcherized mouth and eyes. It looks something about that image
looks a little bit cabinet of doctor Kaligari. There's just I don't know.
It's evil. It is, but you wouldn't necessarily if you saw upside down face Adele. You know, if you saw that your face Adele on the street, you wouldn't think, oh, there is a denizen of Hell. It's like there is a lady. I don't know. It doesn't look bad crazy at least at first glance.
Really wow, Okay, I don't know, I'm seeing something different.
I don't know. Of course, with the Adele image, are the lips flipped.
Yeah, yeah, you're not noticing. Wow, you're not noticing.
No, no, no, clip, I'm looking at like where is the larger lip? And yeah, yeah, I mean I guess yeah. As we'll discuss, like this is part of what's going on in the mind. The way it's you know, stitching things together but not seeing her teeth. I think is very clear here because the toothy images are the ones that turn a toothy smile into a grimace of hell.
Yes, like I said, yeah, the big the big toothy smile is like the most extreme, hell infernalizing of the images. But still something typically looks wrong when you see the head right side up and the eyes and mouth upside down. So you know, in a sense this might not be surprising you screw around with human facial features. You flip people's eyes and mouth upside down, keep the rest of the face right side up, it is probably going to look to some extent wrong and grotesque. But here's the
psychologically interesting thing. If you take one of these hilarious cursed faces and you simply turn the whole image upside down, the effect becomes, to many observers almost completely invisible, or at the very least significantly more difficult to detect. So a thatcherized face turned upside down just looks like a
normal face turned upside down. You don't see the grotesque inversions unless you're really taking your time and looking for them, or unless you rotate the image right side up again, and then you recognize the horror immediately. So isn't that interesting an upside down face? Just turning a head upside down obscures otherwise comple completely obvious mutilations of the image.
Yeah, what is going on here? Yeah?
So this effect was originally discovered by a British psychologist named Peter Thompson working at the University of York in nineteen eighty. It was published in a very short paper in the journal Perception with the title Margaret Thatcher a
New Illusion. So the paper is just a few paragraphs and an accompanying image Thompson, And in fact there's no experiment in the paper at all, I think, because the strength of the effect is immediately apparent to anybody who just looks at the image and flips the paper upside down and right side up, Like, you don't really need an experiment to see something interesting is going on here. So in a very brief background section. It's like one
paragraph long. Thompson refers to previous researchers who had proposed that upside down faces are more difficult to recognize, perhaps because within them it is harder to recognize facial expressions. That was kind of a strange claim to me. Maybe I admit that maybe I don't understand something about what's being positive there, But I was thinking, why would it be expressions that make that make it harder to recognize upside down face? And again, maybe I admit there's something
I don't understand. But Thompson says that it says that since the eyes in the mouth tend to convey the most information about emotional state through facial expression, quote, it seems possible that an inverted face in which the eyes and mouth remain the normal way round might preserve the facial expression better than a truly inverted face. So he decided to try it out, and in another source in a minute, he's going to give a different kind of
explanation for his inspiration to create this image. So there might be multiple reasons this.
This I don't know.
Early photoshopping experiment actually came together, but for whatever reason, he did to try out the mouth and eyes in version. So he cut out the eyes and mouth of a photo of Margaret Thatcher that he got from a poster from a student organization, and he flipped him upside down relative to the rest of the head. And he observed that, strangely, when you are looking at the whole image upside down, it doesn't really seem to change her expression.
Quote.
However, Figure two, which can be viewed by rotating the page one hundred and eighty degrees, reveals that we have been cruelly deceived by the smiling mis Thatcher of figure one. Her two faces are now dramatically different. Returning to figure one, meaning flipping the page right side up again, it is still very difficult to perceive the eyes and mouth rotated version as we now know it to be.
And looking at an example of this, it is crazy. I know that I should, or I know that I should expect to see some different you know. Yeah, but the two images really like match up pretty well. The only thing that really jumps out at me is just the obvious place where you can tell that something had been cut and yeah, pasted, you know.
Yeah, I would not looking at the thatcherized version of the of the face upside down, I would not notice anything was weird about it. It is not until you rotate it that you start to see the way something's wrong and then oh, oh, okay, yeah that's totally wrong. And I guess it's like a partially dawning awareness, like as you turn it around. But so you've got the
core components here. You got the face editing, which is immediately overwhelmingly apparent when the face is right side up, but then it mostly vanishes and looks normal when the picture is upside down. There's also I think a bit of dry political humor in this short paper. It's so dry you can't even really explain it. But just one example is the acknowledgment section of the paper for where Thompson says, quote, I thank the your Conservative Association for supplying the stimulus material.
This being the post organization that provided the poster. Ok.
Yeah, the conservative organization that gave the political poster. Yeah. I don't know, maybe I'm reading into that, but that was a funny sentence to me.
So this was going up on like college students' walls, like conservative college students walls.
No, I don't think it was a poster like, oh, I have a Batman poster in my room, or it wasn't like the Einstein with the tongue out poster. I think this is more like a campaign poster, political poster for the you know, for the political organization for conservative students.
Okay.
So, in the years since Thompson first discovered this, there have been many experiments demonstrating versions of the Thatcher effect with human subjects. It has proven especially in interesting as a way of exploring how humans recognize the faces of other humans. So experiments will often take the form of tasks where subjects have to look at pictures of faces upside down and right side up and judge as quickly as they can whether faces have normal features or whether
the face has been thatcherized. And as you just imagine trying to do one of these tasks, it would probably be almost infuriating how difficult it is to figure out whether the upside down face is altered or not. I was reading a bit more about the history of the Thatcher effect in an entry in the Oxford Compendium of Visual Illusions edited by Shapiro and Todorovich, and this entry on the Thatcher effect called about face is actually by Peter Thompson, the same guy who discovered it, and he
tells a story here that's kind of interesting. He gives a slightly different account of exactly how he first discovered this, how he ended up at the photo editing task. Here he says what he was really trying to do was demonstrate something for his students. The idea was that at a distance, some fine details of an image, like a human face, would be undetectable, but then as you came closer,
the details would become clear. And so he originally made the he says here he made the altered Thatcher face with the eyes and mouth inverted to show this principle. I think the idea was you'd hold it far away and students would be like, ah, yeah, that's just a picture of Margaret Thatcher. But then you would come closer
and be like, oh, something is wrong. But he says, it just so happened that in the process of doing of making these materials, he happened to see the thatcherized image upside down, and he realized that when they were upside down, these images looked the same. The thatcherized and unthatcherized version looked the same, despite how obviously disgustingly different they were when oriented normally. So I love when you get these little accidents.
Just because he happened to post it down on the on the desk upside down, and then then you got the deeper revelation about what's going on here.
Yeah. Thompson also points out some interesting historical forerunners, not to the Thatcher effect, but just to differences in face perception based on vertical orientation. So in this century, he cites the work of the sixteenth century Italian painter Giuseppe Arcimbaldo, who live fifteen twenty seven to fifteen ninety three. This guy was a court painter and a master of festivals for three Holy Roman emperors. You have probably seen his
paintings before. He likes to, or I guess liked long ago, liked to make images of people or humanoid figures out of assemblages of smaller inanimate objects like food items or books. So some of these composite images, you have somebody who is one level of resolution, it's like a you know, a jurist or a barrister or something. But then you zoom in it's like the face is a roast chicken. And then there's a you know, and the ear is a clam or something. It's just a bunch of food.
Yeah. I long loved these images. Yeah, yeah, they there's a surreal nature to them that you're just like, wow, this is like this, this is such a singular vision.
But some of these playful images are clearly supposed to be up down reversible. So there's one called the vegetable gardener, and there's another one called reversible Head with a basket of fruit, and they are only really recognizable as human portraits when oriented one way. You flip them around vertically and they don't look like humans anymore. They just look like bowls of produce. Rob I don't know if you can tell that. I've got examples for you to look
at in the outline here. I would say, both of these immediately look like people upside down. Flip them right side up, and I don't see the face anymore. It's just a bowl of fruit and vegetables.
They're The crazy thing is, if you're looking at the both versions side by side, it's hard to not see the face in the version in which the bowl is right side up and the face is upside down. Because of this effect.
Yeah, so again that's not quite Thatcher effect, but that is, like, there's something weird going on when we're trying to process faces upside down or things that look like faces upside down, And Thompson goes on to note that before he discovered the Thatcher effect, it was well known in psychology that the recognition of faces in particular paid an especially high penalty for up down inversion. Experiments show that basically every type of image with a regular updown orientation takes people
longer to identify when it's upside down. So whether it's a dog breed or a vehicle like a car, or an airplane or a building, any of these things that are normally vertically oriented one way in the world, it's harder and takes people longer to recognize them and say what they are when they're upside down. But the point is,
so that's not abnormal. It's true for all up down objects basically, But the point is that the gap between how easy faces are to identify normally versus how much harder they are to identify when upside down is especially large. Faces in particular pay a special inversion penalty, and Thompson argues that we still actually don't fully understand the cause of the Thatcher effect, but I thought i'd run through
a few common interpretations, partial explanations, and subsequent findings. One thing is that a widely cited at least partial explanation of the Thatcher effect goes something like this. It is differences in human faces are actually quite small. In one sense, all human faces look basically the same, but they look very different to us because we are highly sensitive to tiny differences in human faces, because we need to be.
We need to.
Use that information to recognize identity, who is this and expression how are they feeling? This is extremely important information to us, often life and death information, literally, to know who you're looking at and know how they're feeling.
Yeah, yeah, I mean we've all been in that situation where you see someone out in a public setting and you have that moment where you're like, is this person the person? I think? It is? Like they look up just enough like someone you used to know, and then you feel that kind of like social pressure whether you should acknowledge this or not or keep it to yourself, and you know, social pressure is no small thing for the human animal.
Yeah yeah, Oh, I mean I would say in our ancestral environments, that social record ignition and recognition of feelings probably literally was a difference between you know, it could be difference between meeting a friend and having a deadly encounter, or navigating tense social situations if you were not accurately recognizing other people's emotions, that can be very dangerous. Yeah, So in order to recognize faces quickly and accurately, our
brains have special adaptations. We humans tend not to look at faces feature by feature, but in a holistic way, taking in the whole thing, the whole face at once, and recognizing it based on a sort of at least in part on the spatial relationship between all of the features put together, kind of the total map. And this is what experts call, I think, the configural information view
of the face. But the configural representations is only works when the face is in its normal orientation, or it only works fully when the face is in the normal updown orientation. When you turn the face upside down, configural recognition fails or is impaired, and then we have to fall back on other systems to try to understand the face we're looking at. So we might have to fall back on looking at the face feature by feature to
try to make sense of it. You look at the eyes, and then you look at the mouth, you look at the nose. You're trying to piece it together, one thing at a time, and in this feature by feature system, it is harder to notice that the mouth is turned grotesquely upside down relative to the nose and the chin. Instead, you're going feature by feature and you're like, yep, that's a mouth. Everything checks out.
Yeah, this is fascinating because this is exactly what you can kind of feel this happening when you have that moment where you think you recognize someone. Your brain is like, we have a holistic match, and then we're like, okay, on to the next level of analysis here, what does the mouse look like? And so forth.
Yeah, so regarding the Thatcher effect, you know, yeah, so you're maybe going more feature by feature when a head is upside down, But then you rotate the image and then it's like the configural processing comes back online again. It becomes easier at least, and then you see, oh, oh, things are not fitting together.
Something's wrong.
And Thompson seems to think this explanation is not completely correct. It may be partially correct, but Thompson thinks it still doesn't explain everything, and there are mysteries that remain about the Thatcher illusion, like some results don't fully match up with that broad story about what's going on there. But
there are other interesting things. One is that, strangely, the Thatcher effect seems to be not always, but often reduced or atypical in people with the condition known as prosopagnosia or face blindness. Yes, the term face blindness. We've talked about this on the show before, though it's been a while. It can sometimes give people the wrong idea about what prosopagnosia is. So to understand face blindness, do not picture. Do not picture people with their faces blurred out or invisible.
People with face blindness can actually see faces just fine. They have normal visual processing and normal ability to see, so faces probably look the same as they do to us. The problem is that people with face blindness do not recognize familiar faces, sometimes even including their own face in the mirror as easily as people with typical face recognition. And for people with face blindness recognizing faces, it's just not easy and automatic like it is for most people.
It often requires effortful attention and deliberate memorization of specific facial features, so people with face blindness have to make a mental map like Jim is the guy who has brown hair and a mole beside his left eye, and they can remember based on the individual feature processing. Face blindness is most often associated with dysfunction in a region of the brain known as the fusiform gyros or the
fusiform face area. The FFA could be a dysfunction in the FFA or within a broader network of brain regions that work together to process faces. So a network of regions that include the FFA and this FFA based network is what we use to engage the holistic or configural
processing a near instant recognition of faces. Dysfunction anywhere in this system or in the fusiform face area can lead to prosopagnosia and can be caused by either congenital disorder or by brain injury can be acquired later in life. But the interesting thing is people with face blindness, on average, are less subject to the Thatcher effect than people with typical face perception, so the thatcherized faces are sometimes easier for people with face blindness to see as grotesque even
when upside down. And this fact, which is strange to imagine, but this is part of the evidence for the idea of holistic or configural processing being key to the Thatcher effect, because you know, people on face blindness have to fall back on featural processing to identify faces anyway.
Oh wow, So yes, yes, they don't have the pronounced like first pass recognition ability. They're not cost they're not caught by like first pass recognition illusions.
Yes, interesting, but from what I've read, it's not like it's not as simple as it just just Thatcher effect turned on for typical face recognition and turned off for people with brosopagnotia. Instead, it's more on average it's reduced for people with face blindness, so you know, some individual
results vary, so anyway, that's your effect. I think is a great subject because of not only how hilarious and cursed these images look, but it really does raise interesting questions about how our brains work the way they do. And you know, mysterious process is like recognition, Like when you really start to think about what recognition is, the sense of familiarity we get when we identify an image, and like how that sense is generated in the brain.
It becomes a more and more fascinating and mysterious process.
Yeah. Absolutely, all right, well, at this point I think we can acknowledge, let's see, everything is upside down, but there's also no upside down. Things that you think are right side up are actually upside down, and things that you think are upside down or actually right side up. I think that about covers it.
I think that's right. And when things are upside down, you might not notice things about them. There might be a i don't know, hidden alterations slipping beneath the detection level, so you know, scrutinize those upside down images.
Yeah, yeah, I'd love to hear back from anyone who who after listening to this, or just outside of the experience of listening to this, I have tinkered around with like these stature images, thatcherized images, or if you've ever experimented with some sort of perception altering goggles, you know, some of this will also venture into the world of VR, I know, in which you were essentially putting on some sort of goggles that are giving you an augmented or
completely different visual feed of what the world is. Yeah, all right, well we're going to go and call it there, but yeah, we'd love to hear from everyone out there. Just a reminder that Stuff to Blow Your Mind is primarily a science and culture podcast with core episodes in two season Thursdays, a short form episode on WIN and on Fridays, we set aside most serious concerns to just talk about a weird film on weird House Cinema. Wherever you get the show, We're just happy that you're listening
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