Transcript 10 | “Reconstructing the Natural History of Awareness”, with David B. Edelman

Kate Armstrong

So welcome to this week's or this month's lecture of interspecies conversations. So this is a regular online lecture series that gives the opportunity to invite leading professors, scientists, and researchers to share and present work that contributes to advancing the acceleration and understanding of the diversity, forms and functions of communication in other species. 

So, today we're joined by Dr. David Edelman, and this will be a talk titled “Reconstructing the Natural History of Awareness: The Octopus as Muse and Guide”. So, cephalopod mollusks, particularly the octopus, have fascinated people across many cultures for the thousands of years, and they certainly fascinate us here at Interspecies through their appearance it seems utterly alien to our human sensibilities that there is something strangely familiar and engaging about the countenance and behavior of these tantalizing animals. In David's talk, he will begin by reviewing his own work as well as recent revelations by other researchers regarding the nervous system and behavior of the octopus. He will then explain why this animal, certainly the most complex of all invertebrates, may provide a plausible window into the origins of sensory awareness, as well as a useful model for studying consciousness in animals without backbones. So, over to you, David, and thank you very much for joining us.

David B. Edelman

Thank you very much, Kate. I really appreciate it. I'm just going to share my screen now and we'll see that this works. I think it works. Yes, everybody sees it. Good.

Kate Armstrong

We see your screen.

David B. Edelman

Excellent.

Kate Armstrong

We might want to put it in full screen mode. We see some other.

David B. Edelman

Aha. Interesting. Okay, here we go.

Kate Armstrong

There we go. This is perfect.

David B. Edelman

Gotcha. Okay, great! 

So, thank you all for coming and thanks to everyone at Interspecies Internet for hosting this and for inviting me. 

It is a very sort of fascinating and pregnant subject, of course. And, you know, just a mere few decades ago, it probably would have been controversial enough to have not invited, well, not invited much sort of liberal discussion in and around it. But times have changed and I think it's a sort of a very timely point that we find ourselves in. So, without further ado, I want to get started here. Let me just make sure I can get the screen moving. 

Hello… Okay, so I'm going to give you kind of a contours of the talk slide just to give you an idea of how I'm going to do this. 

I'm going to talk about… Well, Natural History, Evolutionary History, really, and the utility of what I call analogical reasoning. And when I say analogical reasoning, I'm talking about the idea that we can look at the remnants of creatures, or evidence of creatures, in the distance past, evidence of their behavior, evidence of any number of things. And we can kind of analyze it with regard to present day animals, their biology, their morphology, their behavior. And there's a great deal of, there's a great deal of utility in this. And I'll get into this in a minute. I'm going to focus at the beginning on the so called Cambrian explosion, when I believe there was a real revolution in terms of a transformation from sort of perceptual 2D environments to 3D environments. And within a very short period of time, well less than 40 million years, eyes were sort of everywhere we went from eyeless creatures – plants and eyeless creatures – to eyes everywhere. And by the way, when I'm talking about 2D to 3D transform in the Cambrian, I'm talking about the idea of a sort of a sheet at the bottom of the ocean, a very simple sort of sheet of growth, not much else going on through the vertical column of the water. But then a change happening and all of the sudden an environment sort of rich with sort of diverse life at different levels of the water column and animals that began to move around, among other things. 

I'm going to focus as well on animal eyes, distance vision and the representation of space and time in the nervous system because I think these things are all inextricably linked. And I hope I can be persuade you of that as I go along. I'm going to give you a definition of consciousness because of course that is still somewhat controversial. I have my own idea, which you'll see shortly. We're going to talk about the octopus's model and muse, of course. And then I'm going to kind of give you my take on what I believe to have been the natural history of, or what I believe, is the natural history of awareness. A sort of a sequence of innovations that occurred that, that facilitated the appearance of consciousness on Earth.Gotcha. Okay, great!

So, thank you all for coming and thanks to everyone at Interspecies Internet for hosting this and for inviting me.

It is a very fascinating and pregnant subject, of course. And, you know, just a mere few decades ago, it probably would have been controversial enough to have not invited, well, not invited much liberal discussion in and around it. But times have changed and I think it's a very timely point that we find ourselves in. So, without further ado, I want to get started here. Let me just make sure I can get the screen moving.

Hello… Okay, so I'm going to give you kind of the contours of the talk slide just to give you an idea of how I'm going to do this.

I'm going to talk about – well, natural history, evolutionary history, really, and the utility of what I call analogical reasoning. And when I say analogical reasoning, I'm talking about the idea that we can look at the remnants of creatures, or evidence of creatures, in the distant past, evidence of their behavior, evidence of any number of things. And we can kind of analyze it with regard to present-day animals, their biology, their morphology, their behavior. And there's a great deal of, there's a great deal of utility in this. And I'll get into this in a minute. I'm going to focus at the beginning on the so-called Cambrian explosion, when I believe there was a real revolution in terms of a transformation from perceptual 2D environments to 3D environments. And within a very short period of time – well, less than 40 million years – eyes were everywhere. We went from eyeless creatures – plants and eyeless creatures – to eyes everywhere. And by the way, when I'm talking about 2D to 3D transform in the Cambrian, I'm talking about the idea of a sheet at the bottom of the ocean, a very simple sheet of growth, not much else going on through the vertical column of the water. But then a change happening and all of a sudden an environment rich with diverse life at different levels of the water column and animals that began to move around, among other things.

I'm going to focus as well on animal eyes, distance vision and the representation of space and time in the nervous system because I think these things are all inextricably linked. And I hope I can persuade you of that as I go along. I'm going to give you a definition of consciousness because of course that is still somewhat controversial. I have my own idea, which you'll see shortly. We're going to talk about the octopus's model and muse, of course. And then I'm going to kind of give you my take on what I believe to have been the natural history of, or what I believe is the natural history of awareness: a sequence of innovations that occurred that facilitated the appearance of consciousness on Earth. 

So, without further ado, I'm going to start with an allegory. It's not exactly a shaggy dog story. I won't make it too quick because I want you guys to follow. But it illustrates an important point about evolutionary history. So, I'm going to tell you the story first. 

A guy is on his way home. He's on the New York subway. He's on the F train going to Brooklyn from Manhattan. And he is getting increasingly agitated and angry because he has on his mind this idea that his wife is having an affair with someone else. And as he approaches home, he gets increasingly angry and, you know, almost uncontrollably so he reaches his walk up. He walks up five stories in the summer heat. It's the dead of summer. It's July, it's 90 degrees out, 90% humidity. 

He gets upstairs and he looks around thinking, “Where is this guy? Where is this guy? What's going on here?” He rushes out onto the fire escape. He looks directly below and he sees this young man – disheveled young man – wiping his brow. And he gets this spurt of angry adrenaline. He grabs the nearest heavy object, which happens to be a refrigerator, and he drops it over the edge of the fire escape onto the guy's head. And then subsequently dies of a heart attack in the process. The scene shifts to heaven. There are three men standing before St. Peter. St. Peter looks down at them and says: 

The scene shifts to heaven. There are three men standing before St. Peter. St. Peter looks down at them and says:

— Well, gentlemen, you all know, of course, why you're here. But we need to go engage in a bit of a formality. You're all in—you know, it's no problem there—but I need to know how each one of you ended up here.

Guy number one, what's your story?

— Well, St. Peter, I thought my wife was stepping out on me. I... I was getting really, really, really mad. It was a hot day in the middle of summer. I rushed home. I got to my apartment. I started looking around for the guy. I couldn't find him. I rushed out onto the fire escape. I saw this guy below wiping his brow. I got uncontrollably mad. I picked up the refrigerator, dropped it on his head, and died.

And St. Peter said:

— Okay, that's fine, you're in. Okay… Guy number two, what's your story?

— St. Peter? I don't know. You know, it's one of those things. I share this apartment with my girlfriend. I stepped out on the balcony because it's really hot outside. I wiped my brow, and all of a sudden this refrigerator fell on my head.

St. Peter said:

— Okay, I understand. Guy number three, what's going on?

— Ah, St. Peter, I don't know. I was just sitting in this refrigerator minding my own business.

Okay, so here's the point to that story. And by the way, I can't take credit for the story. This story is my late father's. He loved this story—and he loved it in particular as an illustration of natural history, in a way, evolution: the idea that you can't see the big picture. You can't see what's going on until everything has sort of already happened, and then you can piece it together.

So, that is one of the tantalizing and engaging, as well, points about natural history—about evolution. It's largely a reconstructive sort of science. It's not a benchtop science, for the most part. You have to sort of reconstruct things, and you have to look to living animals to get an idea of what was going on in the past. So, you can link clues about the past, for which you have a very limited record, to the morphology, the physiology, the behavior of living animals. And that's an important point here. So you'll see how important this is to my thinking as I go on.

All right, so I want to sort of introduce you to sort of the evolutionary sort of convergence. Well, the idea of evolutionary convergence, the rules of that game. So, first of all, the idea of evolutionary convergence is relatively simple. It's the idea that similar environmental conditions can give rise to similar biological adaptations. And it used to be thought that this was relatively rare way back in the earliest point in, in terms of natural selection and Darwin's thinking, this was thought to be the case, that this was a relatively rare thing. It's not believed to be that rare anymore. In fact, it doesn't seem that rare at all. You can find examples of this everywhere, and you'll see this in a second. It also points to a very important idea, I think – and perhaps a universal idea – which is that there are very powerful constraints on animal form and function. That is, you can't go too many paths toward a solution to a particular problem the environment presents. Okay? 

Focusing eyes are an interesting example of convergent evolution because they've appeared not once, not twice, perhaps not three times, but a number of different times in the course of evolution and really almost all in the Cambrian to begin with. 

Okay, another important point. Now we're at the back end of things. So, when the eye sees something, there's something behind that eye that has to process what the eye sees. And that's clusters of neurons. That's nervous systems. That's brains. Well, basically, as the great Oliver Sacks once said, a neuron is a neuron, more or less, regardless of species, neurons do largely similar sorts of things, regardless of what animal you may find them in. 

Finally, familiar brain circuitry. Now, this is a little bit controversial, and I don't think everybody has spot this idea, but the idea is that there are only so many ways that nervous systems can encode different aspects of the world. And in particular, with regard to what I'm talking about today, among other things, space and time. But I'm beginning to believe that's pretty much true. You can't solve certain problems more than a couple, perhaps only one way when it comes to how the nervous system encodes aspects of the world. 

Exploration of evolutionary Biology

Okay, so I'm giving you the baseline for what I'm talking about. Now, let's just pick an example of convergent evolution. So, you see here, this is a classic example: You have the arm or the leg in certain animals – the foreleg or the arm in a human or the wing of a bird – and they consist of all of the same bones, more or less. Some bones get lost over the course of time. But essentially you see in mammals, in birds, you see essentially the same bones giving rise to certain kinds of… to a structure that is tasked to do a certain function. In the case of human beings, it might be manipulating the world or locomotion, depends, in the case of birds, in the case of bats, it's for flight. But if you notice in the case of the bird and the bat, it's different bones that are tasked for different structural aspects of the wing. Okay, so the wings, the bones or the finger in the bat serve the purpose of giving the wing its overall structure, holding the web out. In the case of the bird, that's not really true. Birds have feathers. This is a very kind of granular example of convergent evolution. The examples that I'm going to harp on later of course, is the eye. And that is, you know, that is an innovation that appeared in different species quite independently in many cases. And in the case of the octopus, that's certainly true, the octopus relative to vertebrates, it's very true. So, the last common ancestor of octopus and human was an eyeless, basically a sightless worm that didn't even have a central nervous system. 

All right, so moving right along. Cambrian is kind of a sensory, it's kind of a renaissance of sensory richness. And it presents the sensory world in three dimensions, which introduces certain challenges to animals. And in the case of invertebrates, you can see there was a veritable explosion of invertebrates and in particular invertebrates with different kinds of eyes. So when you're talking about eyes, obviously we're talking about vision, we're talking about the reception of light or aspects of light. Reflection, transmission, absorption and scattering. So wavelengths of light and differentiating those wavelengths and light has certain physical properties. And so these so called spectral properties of light, they result in, they yield different types of wavelengths which animals of many animals can discriminate. Polarized light is, or polarized light is another Sort of version of this sort of input. And it's invisible to many animals, including us, but quite visible to, to a number of different animals across many genera. And the cephalopods are certainly animals that are capable of perceiving polarized light, as well as certain birds. So light becomes particularly important in Cambrian ecology. Appearance of mobile animals sort of changes the picture initially. And then you have these moving animals that are, they're ambulating around at photic depths. What I mean by photic depths is depths at which light is sort of meaningful. That light penetrates to some extent or to a lesser or greater extent. So basically more, less than 50ft, give or take. And as soon as animals could sort of see within this sort of part of the vertical column of water, it enabled them to exploit far flung food sources and novel predatory strategies. And there was sort of an arms race of innovations. So you saw the rise of predator species and prey species, animals with faster locomotion, animals with armor, animals that were able to mimic certain peptides, certain small protein component signals that would allow them to somehow deceive or evade other animals and a variety of other defenses, as well as certain refinements and vision. Okay, so eyes appeared many, many times, but spatial acuity at distance, I think is much more unusual. And I think in this case it's relatively important. It's particularly important to my argument. So light sensing organs aren't really full blown eyes. They're sort of one step on the way toward being an eye. Simpleeyes, we can point to many examples of simpleeyes. And simpleeyes are a situation in which you have cells that are essentially receiving light. They can pick up light, but you have to have some sort of pigment that separates each of those cells, that allow those cells to sort of come up with some sort of primitive spatial representation of that light. So it's almost like an array. If you don't have the pigment between those, those cells that are receiving light, that organ is not going to be able to do any kind of discrimination, reasonable discrimination, certainly not even a course good coarse spatial discrimination. Except save the idea that if an animal has a spot on left side and a spot on the right side, it might be able to sort of say roughly, well, something is moving in the left, to the left direction, something is moving toward the right. And I can see that because one eye spot is picking up more light than the other. And that's about as much as you can do with that kind of an eye. So at this point you get this proliferation of different Types of eyes. I'm not going to dwell on this. There are more important things to talk about soon. But you see different kinds of eyes. You see the chambered eyes, the eyes of a chambered nautilus. You see here the eye of an octopus. Now, the eye of a chambered nautilus is essentially a pinhole. There's no lens. The eye of an octopus is rather different. There's the introduction of a lens. And the lens can be moved back and forth very, very similar to that of a camera. So now you have an animal that can discriminate to some extent near versus far objects. That becomes a theme that you see in other animals, of course, as well, including the vertebrates. And then you have compound eyes. Now, compound eyes can do a lot with space. They can sort of represent spatially where something of varying wavelengths is. But it's not necessarily terribly accurate in terms of space. It gives you a rough idea, depending on the species, some are better than others. And it may not be good in the case of distance vision, although there may be a little bit of debate about that, that. So here at the top, you see an animal, a jumping spider, that has a focusing eye. But they have a completely different motif than other animals with focusing eyes. Their pupil is more or less a column that shifts around within their eye. And when the animal is looking at an object. The unsettling thing about looking at a jumping spider in the eye or in the eyes is when, when the jumping spider sees something off, say to the right, you'll see those two columns go and shoot to the right. So you can sort of see what they're. You can get an idea of what they're looking at. Then you have the mantis shrimp, which has a compound eye, but is very capable of discriminating huge numbers of different sort of ranges of wavelengths. Okay, so here's a general picture of the different motifs of eyes. So you get the idea. Eyes proliferated explosively during the Cambrian. So now, on the back end, a question I've asked myself for a long time is, well, you have these eyes. If you have a focusing eye, there's a lot of potential information coming in. You have to have a nervous system that can do something with that information. In other words, eyes don't evolve in a vacuum eyes. You know, if a focusing eye appears, it stands to reason that there's some sort of neural substrate behind that eye that can process all the information that eye is bringing in from near scenes, from far scenes, etc. So you can't have One sort of without the other. And so the question I've asked myself is have similar properties underlying sophisticated functions and behaviors? In this case, a function being visual perception emerged in nervous systems which are radically different than the nervous systems we find in vertebrates. Octopus vision sort of offers a clue and I think a very good opportunity. 

We've identified analogs of different sort of nervous system structures, analogs of a vertebrate brain structure in very distant animals, including some invertebrates. In the case of, for example, the hippocampus, which is associated with memory formation, retrieving memories, we see that there is an area of the honeybee, the fruit fly, the insect brain. Many insects have something called a mushroom body. The mushroom body seems to be doing the sort of similar heavy lifting as the vertebrate hippocampus. In the case of cephalopods, this is a squid brain, but you get the idea. There are areas in this case the vertical lobe and median superior frontal lobe, which are linked structures in the octopus brain, they're higher structures. Physically, in the octopus brain, they're doing what looks like work that's similar to that of the vertebrate hippocampus. But they're almost a hybrid. They're maybe not just hippocampus, but also maybe something like cortical function. We're not really sure. We've identified certain physiological traits in an animal like the octopus that are essentially akin to those we find in vertebrates. 

So, this is an experiment that was done many years ago. David Glanceman, in a review article, talked about it. But the idea that you could give an octopus a shock from a ball on a Lucite stick, the animal could be trained to avoid that shock. To avoid that ball. Excuse me, associating with the shock. Well, you could actually see in that animal, you could essentially do a recording, or in this case, you could stimulate, use a stimulating electrode. And you could see that that animal was using sort of one of the physiological building blocks of memory that we also find in invertebrates. This is called long term potentiation. It has to do with a change in the synapses between neurons that facilitates something like memory. So, we found this in the octopus. That's a pretty old finding. We know that relatively modest nervous systems can generate impressive behaviors. On the right, you see fruit flies fighting over essentially a plate of food. In the second piece, you see honeybees watching a waggle dance to sort of get an idea of where food is located out in the big wide world. And on the third, you see a jumping spider sort of leaping on, I believe it was a bee, but my screen is obscured. And the fourth, you see a cuttlefish exhibiting certain kinds of body patterning. So these are pretty sophisticated behaviors. This is not nothing to scoff at. But these aren't nervous systems that are anywhere near as large as the nervous systems of vertebrates. Okay. 

Understanding Conciousness

So, a question that many people have asked for many, many years is how much and what sort of a brain is required for conscious experience. And I think that's still very much an open ended question. I could probably get into an argument with Christophe Koch about whether bees are conscious. I think they might be, but I would have to modify some of my own arguments to sort of accept that. But I'm agnostic, perhaps. I think that they could very well be, but I'm gonna have to do some digging before I sort of really conclude that. So, what about outside the vertebrate lineage? Well, let's start with the definition of consciousness. That'll put us on a better track. Now, I have a sort of a modest definition. I think of consciousness as a stitching together, or as many would say, particularly in the world of philosophy, binding of many closely contemporaneous sensory threads. That is sensory input that's coming in perhaps from different channels or from different sub modal aspects of an organ like the eye. And that's coming in more or less simultaneously or closely spaced in time. And the brain, the nervous system is somehow stitching those different threads into a coherent unified scene. And, and the animal perceives it as such, as a coherent unified scene. That scene also in my mind, has to persist in memory. That is, there somehow has to be a link between perception and memory in order for consciousness to arise. That is a super important bit of the nervous system that has to have arisen in order to facilitate conscious experience. So conscious states are bound scenes that offer content which is correlated in time. Okay, beyond that, that you might get from segregated sensory inputs. Just imagine an animal getting, you know, hearing a sound on the one hand and seeing something on the other hand, but not necessarily having any kind of connectivity, neurally speaking, between those, those things. So sensory inputs don't, in animals that are conscious, don't remain segregated for long. Okay, so this suggests that there are a surprising number of non human animals that are capable of subjective experience. All right, so let's lay out some basic criteria for consciousness. I think across the board you have to have, and this is based on observations, invertebrates in particular, in mammals and humans specifically, because humans can give us a, a form of accurate report as to what they're experiencing. So you have to have brain regions that function like thalamus and cortex. What do I mean by that? Well, the thalamus is sort of a sensory relay that brings in senses, in the case of the mammals, brings in the various senses, except for the most part for smell. Smell is a very interesting sense because it essentially all but avoids the thalamus. But all the other senses come in through the thalamus and they hit the cortex. And. And there is a recurrent connection between thalamus and cortex. Cortex being the area where you keep your stuff. Okay. If you're a mammal or if you're a bird, because birds have essentially homologues of cortex and perhaps other vertebrates as well. So you have to have some sort of connection between the thalamus and the cortex going on. And that is sort of part of that link that I talked about between perception and memory. The cortex is where essentially memory is. Much of memory is stored. Thalamus is what allows the sensory world to connect to the cortex. And then there is some sort of recurrent signaling going on between those two. You have to have dynamic brain activity. In my mind, I think we're going to find that a lot of animals, even perhaps certain invertebrates, have dynamic brain activity that is the pattern of firing neurons across certain brain areas that resembles what we can observe during the human conscious state. I don't believe that there are nine ways to skin that cat. I think we're going to find similar motifs the more we look. But we're at a very early period in terms of sort of proving that finally, the ability to make sophisticated discriminations, and those sophisticated discriminations a lot of them have, they're essentially connected to the idea of this deep reciprocal connection between perception and memory. Without that connection, you can't make such discriminations. The interesting thing about this observation or this notion is that there's a lot behaviorally that you can observe in non-human animals without them necessarily even giving you a report that suggests that they're actually doing this very thing, that they're making sophisticated discriminations. Okay, all right, so let's move on to the building blocks of consciousness. I believe, and this is just me, you know, I'm not necessarily in the minority, but I may be. I think consciousness is contingent on what I would call fast sensory channels. I think of vision as a “fast” sensory channel because it is coming in very, very quickly. And light itself essentially travels, of course, travels very, very quickly. I'll contrast this, for example, with smell. Now, many animals are capable of producing sort of a very sophisticated 3D sort of model of the world based on smell. But it's very, very coarse. And of course, as you know, smell is really interesting. It dissipates over greater distances. Light can penetrate faster and farther. Smell takes a little while. It's not necessarily instantaneous, although as soon as, you know, as soon as particles of a particular odor hit your nose, yeah, you're going to perceive something. But putting all that together in a fast sort of way, it's not giving you the kind of sort of rich tapestry that vision gives you immediately. And I say immediately on purpose, because it is a rich tapestry, particularly for some animals that are quite olfactorily talented. But in terms of speed, it's not at all like vision. You have to have a density of sensory inputs. In the case of eyes, that's clearly the case in many animals. There's a huge number of inputs from receptors coming in from photoreceptors, big bundles of input coming in from photoreceptors. So, a richness in terms of what's coming in, in terms of all of the possible inputs. And then you have to kind of integrate these sensory signals relatively quickly. Okay. And that, you might say, is sort of the key element of perceptual unity. And then finally, that connection to memory, you have to have some kind of working memory for there to be conscious awareness. And that again, harkens to behavioral observations of behavior in different animals. We can glean a lot from what we observe animals doing, how animals behave. We can glean a lot about working memory. And now finally, that old thing, that thing that I harped on before, brain circuitry that links perception and memory. Okay, so those are my building blocks. 

Consciousness in  Octopuses

So, we want to explore consciousness in far flung species. We've asked the question, what is consciousness? I've given you my definition. It raises some practical questions. What brain structures and functions are necessary for consciousness? I told you that one structure found in mammals, the thalamus, is an important structure to look. We should look for analogs of that because it's an important relay that has recursive connectivity and to cortex in mammals, which is where memories are stored. We should look for similar sort of suborgans of the nervous system in non human animals, in invertebrates, in this case. Then we can start sort of mapping the neurobiology, the neurophysiology of putative conscious awareness in vertebrates. 

Well, how do we study this? Well, we take strains of evidence from behavior. We take strains of evidence from physiology was a very relatively new thing among invertebrates. We've only recently developed the tools to look at this sort of physiology in any degree of resolution in the invertebrates. Which animal should we study? That gets us to the octopus. I think the octopus is a good candidate because it has very sophisticated faculties which we know it's learning and it's quite capable learning and memory wise. And its behavior certainly indicate a richness for these sorts of faculties. They have complex nervous systems that can support the above. Very important. We need to come up with a systematic approach. As of late, I haven't been able to do this very well because, well, I built four labs in the past 10 years. I haven't been attached to all four labs. I'm attached to one lab at Dartmouth. But that's a long story. One thing we could do is we could start to map the octopus visual system in earnest. Something that hasn't really been done in any systematic way yet, and map out or work out the neurophysiology and visual perception and memory of an animal like the octopus. Well, I have this hypothesis which you'll see in a second. There are certain pitfalls vis a vis making parsimonious conclusions about how evolution unfolded and how we got to where we are in terms of brain and behavior generally and in terms of consciousness in particular. I don't believe that parsimony is always the case in terms of evolution. We don't have to go into that too much. I do believe that there are constraints on certain kinds of network properties. So if you look at complex nervous systems, do the same general principles apply to all of those nervous systems? And I think at a certain level we'll probably find out that they do. And again, that goes back to Oliver Sacks's old saw. A neuron is a neuron is a neuron. So here we are, functional anatomy of consciousness. We see this connection between cortex and thalamus and what I didn't mention, basal ganglia. In the case of a mammal like a human, we see similar structures essentially at this point, homologous structures. I think we can safely say that there's homology between the telencephalon and the cortex. The thalamus and the basal ganglia exist in birds. And then we get to cephalopods and it's kind of still a black box. All right, so let's get into octopus. I think it's a good candidate for testing the boundaries of consciousness over the course of evolution. It has a sophisticated nervous system, although it's less complex, of course, than the vertebrate case, it's got functional and convergent properties. I mentioned long term potentiation, which is an aspect of physiology you find in the vertebrates. Well, you find it in octopus too. You find it in a lot of animals, you find it in insects as well. Learning and memory quite comparable to mammals and birds. Diverse behaviors across species – You see in different species of cephalopods, in different species of octopus, you see different kinds of behaviors. Those may be driven by possible differences in properties, neural properties driven by certain needs set up by environment, by environmental context, behavioral flexibility that rivals some higher vertebrates. I think that's largely true for the octopus. So, here are the brains of a human, of a zebra finch, familiar structures, again, as I said, a lot of homology. You get down to the cephalopods. And while we started to map certain of these areas, particularly these higher areas like the vertical lobe and the median superior frontal lobe and certain other areas associated with, well, with controlling the chromatophore system, with controlling movement, we've done a little bit of, of sort of mapping of this nervous system, but a lot of it is still sort of in black box territory. Okay, so for probably around 20 years or so, nearly 20 years, people have been able to record brain activity in behaving octopuses. It hasn't been, it's been very coarse relative to sort of the vertebrate case. We're still very early on in this. One of the earliest examples is work that was done by Graziano Fiorito and Benjamin Hockner, among others, where they sunk single electrodes into different parts of the octopus brain. And over the course of months, probably many months, and many animals, they managed to sort of map out or map structure or map brain area to certain function. And they did this both for sensory and for motor. And so this was an important technique. Now in fact, as of a month ago, I believe, well, actually less more recent than that, actually this month.

A group representing various countries, Tamar Gutnik, Mickey Kuba and their colleagues were, were able for the first time to develop a technique to implant electrodes without a tether. Now, that previous example that you saw required that the animal be physically linked by a wire to a preamplifier, to some sort of recording device to record the signatures of brain cells. Well, that's all well and good, except that eventually the animal, more often than not the animal find the wire and rip it out of its head or whipped out of its mantle and rip a part of its brain out as well. That's a big problem in the case of this, you don't have that issue anymore. So this is a sort of a big technological jump. They, they put the, essentially they put the, the hardware, most of the hardware of, of this setup into a waterproof bag. They surgically implanted it in an anesthetized animal, the animal was revived and they could at least get a start at associating certain kinds of behaviors of the animal in time with certain neural signatures, so certain patterns of firing in the nervous system. Now this is a technical tour de force, but there's still a long way to go. They weren't able by their own admission to really document sort of specific behaviors or specific neural signatures to specific kinds of behavior, although they saw similar sorts of neural signatures as are found in other animals, including the vertebrates. So it's a big leap forward, but it's very, very largely technical and we have a ways to go, but this is a very, very important first step. Now, a group that I've been involved with is very interested in this topic. We published a review article some time ago of a little more than a year ago, I guess, and we basically tried to put together a lot of the evidentiary strains that would suggest consciousness in a cephalopod like the octopus. So again, as I said before, impressive discriminatory anticipatory behavior. Cephalopods are clearly big brained invertebrates that are confronting very variable sorts of environments, variable in space and in time. We've started to identify certain neural substrates in terms of their function. We've done this for a while, but we really haven't been able, we really haven't been able to do this in any great systematic way yet for any cephalopods, although I think we'll be getting a start quite soon. Early thinkers, early researchers like Jay Z. Young really actually he thought of the cephalopod brain as a sort of a good model for nervous systems generally, which is quite an interesting take back in the day. But it sort of prompts us to sort of really, really consider the idea of consciousness in a far flung species like the octopus. I think we're starting to see neurophysiological dynamics that are quite interesting. We're starting to observe certain behavioral states like sleep, which may give us the opportunity to identify signature brain waves in the octopus, signature sort of waveforms that resemble the vertebrate case. We don't have much to go on here yet, but I think that that's an important sort of waypoint that we have to kind of get to. 

Comparative Vision: Humans & Octopuses

All right, so let's talk about vision and the octopus. So if you look at the human eye and the octopus eye, there's a lot of convergence here. You can see very similar sorts of structures. These are both focusing eyes. One distinction is humans use ciliary muscle to sort of deform the lens to focus. We don't really pop our lenses in and out, front to back – like a camera to see objects that are further away or closer to us. We don't accommodate doing that. We distort the lens to accommodate. Octopuses don't do that. Octopuses actually move their eye, move their lens in and out more like a camera. It's actually a true camera eye in that sense. Okay, so. But there's a lot of convergence, functional convergence, of course, but structural convergence too. And again, independent appearance and evolution. These did not evolve from a node, a single ancestral animal that had an eye. They evolved both from an animal that was eyeless and essentially did not have a central nervous system that was their last common ancestor. 

Here's just an example. I want you to focus more on the right. If you look at the retina of a mammal, light, when it passes through the retina, it actually goes through all kinds of intermediate processing cells before it hits the receptor. And the weird thing about the mammalian eye, the vertebrate eye, generally, is we have a hole in the middle of our eye. And the receptors, the axons coming from the receptors, are actually they're sort of aimed outward, and they have to make a turn and go back in through that hole into the brain. And the signal again has passed through many layers or layers of many cells. When you look at the octopus, there is no such sort of processing layer in their eye. Light goes directly to the photoreceptor, and then at the back end, there's something going on in what's called the optic lobe, directly behind the retina. The retina is here. The optic globe is behind it on the left side. You see it here. And what's really interesting is it looks for the world structurally as if all the retinal processing cells, all the processing that goes on the retina, has been backloaded into the optic lobe of the octopus. So, the retina is just simply a simple sheet of photoreceptors. The processing is happening in the optic lobe, but the structure of the cells that process it, the way they're wired together, is really sort of reminiscent of what you see in the retina of the eye of a typical vertebrate. And so you see on the right, some colleagues and I did sort of a fly through, we did a 3D reconstruction and you're sort of seeing cells and certain aspects of connectivity as we fly through different depths in the octopus optic lobe. 

So, if we look at the functional aspect of the eye, well, the octopus does very well in terms of acuity. It does really, really well. Look at where it falls in terms of acuity. And these are all done. Acuity is relative to height, in this case, body height. But basically, you see the octopus is between the human and certain birds. But it's quite well placed. Falcons do exceedingly well, of course, not surprisingly, but octopuses do awfully well for an invertebrate. They can see far away, they can see close up, they can accommodate. 

So, the eye presents us with this sort of familiar structure and function. I believe again, eyes don't evolve in vacuum. It's suggestive of critical memory and integration substrates behind that eye, in the brain, in the central brain of the animal. And I think it's a sensory portal that allows us the opportunity to investigate higher brain function and at some point, ultimately the signatures for visual perception. And then perhaps eventually we can link this to how vision is linked to memory, how visual perception is linked to memory. But that's a ways down the road. 

Okay, so when you look at certain features of how vision is processed in the vertebrate, you see certain themes that come up again and again. You see a so called retinotopic organization of that part of the brain that is doing an aspect of visual processing in the cortex, in this case. And so what this simply says is there's a preservation spatially in terms of what cells are being stimulated by incoming signal. There's a preservation of the sensory relationships from the outside. So photoreceptor here, photoreceptor there, somehow that spatial relationship is preserved in the brain. It's represented in some sort of, in a spatial sense in the brain. Okay. In the vertebrate visual system, there's a hierarchical representation, which is to say that the signal comes in through the thalamus, through the lateral geniculate, and it's decomposed into a variety of different sub modal properties, like motion, like differential wavelengths, textures, any number of different things. Light and shadow, it's deconstructed and then reconstructed. But there's a very hierarchical representation in the visual system. As you get in deeper, there are higher processing centers that start perhaps pulling things together, but again, very hierarchical. And then as I said before, there are all kinds of recurrent Pathways. I talked about recurrent or reentrant pathways between thalamus, the sensory relay and the cortex, where you keep your memory, where you keep your stuff. But you can see these kinds of reentrant pathways in vision between, say, prefrontal cortex and visual cortex. And, so you have sort of a feedback stream and a feed forward stream in the case of vision. And these are our re entrant. This is a constant theme in vertebrate brains. Is it a theme in the cephalopod brain? Well, we really can't say that for sure. 

Now, getting back to behavior, there are certain kinds of behavioral tasks you can set forth for the animal to perform that for the world, for all the world, indicate to me the animal has some sort of working memory. So, in this case, I'm going to show you a movie that was taken in Grazia di Fiorito’s laboratory at Stazione Zoologica in Naples. And it shows you the aftermath of an experiment involving what some people call observational learning. What other people social learning. So, the idea is one octopus has learned how to solve this box. This box is a transparent Lucite box that has three possible entry points inside. And, inside there is a living crab or a living shrimp. And the octopus can clearly see the living shrimp from the outside, but it has to figure out which entry point will actually work. So, at the same time that this animal has learned this task. Once the animal has learned the task, you show another animal, the first animal performing the task. Once that first animal has learned the task, you open up a window so that another animal in an adjoining tank can actually see the first animal solving the task: “Ah, this animal goes to, you know, to the portal on the left to get in to grab the crab”. 

So, what you're going to see here is an animal that has actually observed another animal who's learned this. And in effect, no trial learning. This animal goes right to the portal that will allow him and the other portals won't work. So, I'm going to put this up, and I'm going to speed it up a little just so you see. If you look on the right hand side, lower right hand corner, you'll see the octopus, and watch his eye, and watch as he gets more and more interested. He comes over, he looks briefly, but then he goes right to this entry point. And if you watch his web, you'll see that he struggles a little bit, he twists it a bit and then opens it up. And as soon as he opens it up, that poor crab is history so there he's just gotten it open. He reaches in, he grabs the crab. Okay. That, in my mind necessarily has to involve some form of working memory. It sort of seems obvious to me that that has to be the case. Well, that's really important because I would suggest that working memory is something that you. You see in conscious animals. I'm not sure you can make an argument that there can be working memory in an animal that isn't, you know, capable of some form of awareness. 

Okay, so in the lab, we can expose the animal to different kinds of stimuli in order to sort of do, you know, perform these experiments to create these experiments, to build them. You can expose them to natural stimuli. The obvious ones are prey, since they're predatory on animals like crab and shrimp and certain vertebrate fish. You can have artificial stimuli. It can be anything from a white ball that the animal has learned to associate with food. It can be the human being who might feed that animal. On the other side, you have negative stimuli. It might be, in the wild, a moray eel. In the laboratory, it might be a red ball, which the animal has come to associate with a shock. Okay, so we have sort of a toolkit to sort of explore these sorts of things. And I don't want to naysay at all the importance of observing behavior and developing a suite of behavioral experiments to test, to probe for conscious experience in cephalopods. People like Jennifer Mather have done really, really fine work in terms of observing, both in the wild and in a lab or controlled setting, what animals are actually doing, how they're behaving. And a lot of their work actually points to the existence of working memory, and I would say, by extension, conscious awareness at certain points. 

Innovative Experiments on Octopos Behavior

So, this is just a simple video showing you can do some really interesting psychophysical experiments based on presenting a visual stimulus. So, in this case, I've put – this is in Graziano Fiorito's laboratory – I have a camera in this tank. It's hidden in a brick. You can see the little hole that was made in the brick. I had to do this because if I put the camera in by itself, the octopus tore it apart. They would constantly do this! So, I hid it in a brick. It's part of the octopus's den. He doesn't see the cameras there. And if you watch, I'm projecting, using a projector back behind all of this. I'm projecting an image of an extension of his tank. And you'll see what happens when a crab appears in that video that the Octopus is seeing. And we simply wanted to check, is the octopus aware of something that's salient in this video? Because it's an important building block for experimentation. There's the crab running across. And you'll see the animal looks, he goes and tries to attack it. Okay. And then watch what he does afterwards. He pulls back. He didn't succeed, clearly. And he's clearly looking again and he wants to engage again. And he's going to do the same thing again, at that point where he sees the crab. Well, that seems sort of humble, but it's really, really important to do these kinds of little sort of trial runs to make sure that what you're presenting the animal with in a laboratory is garnering, you know, salient responses. So, I'm just showing this as a building block now. One experiment we did in my lab quite a while ago was we applied, we built essentially an invertebrate equivalent of the Mars water maze. Mars water maze is an interesting… Well, it's, it's, it's an interesting sort of task because it involves, it's not actually this. Excuse me, sorry, I misspoke. Not Mars – Barnes Maze. The Barnes maze was developed to look at navigation, and navigation related memory in vertebrates like mice and rats. And so the idea is there, there are numerous sort of fake holes, but there's only real one real hole which will actually lead the octopus into its native water. And it can't see, in this case, the octopus can't see. You really can't see the holes because its eyes are oriented upward. This is a terrestrial maze. The octopus is out of water at this point. You can see him being pulled out a little blind and he's wandering around. And of course he's using touch, but he also will see there are landmarks which are not visible on here. There are landmarks on the side of this maze. There's a plus sign. There might be a square in another location. Well, the plus sign happens to be over the one real hole. So the interesting thing is when the octopus finally learns where the real hole is, he goes to the plus sign. He dives in and hits his native water. Well, if you rotate the maze so that the hole is no longer, the real hole is no longer above or below the plus sign. It's just a fake hole that won't lead him anywhere. He doesn't go to the real hole anymore. He goes to where he saw that plus sign above what he thought was the real hole. And he tries to get into that hole even though he can't make it. So, you'll see that in practice over here. So, here's the octopus and I'm going to kind of mute this and describe what's going on because I think it's a little distracting. The octopus's capability for visual. Okay, let me turn this down. So you see the animal again exploring and you see those landmarks, right? You see the triangle and you see that plus sign. The plus sign happens to be over water. And of course, being in this kind of environment, it's very light, it's very bright and it's out of the water. It's not a great environment for octopus over the long term. Octopuses don't want to hang out in this kind of environment for any length of time. So, there's a lot of impetus for that octopus to get out of there, get back to its native tank. So when we shift that maze now he finds his way in there. Now, when you rotate that, that side wall so that the plus sign is over another hole, not a real hole, the octopus goes to where the plus sign is. He doesn't go to where the real hole was. He goes to the plus sign that indicates that he's now associated that plus sign with escape. It's kind of interesting. And we've done this a number of times. It works pretty well. We still have to do this in a really systematic way, but you kind of get the idea. So, that speaks a lot to memory, among other things, to working memory in particular. And so now I'm going to kind of end things because I think we really have to have some sort of discussion. So, I want to give you sort of my thumbnail sketch of the natural history of, of consciousness and I'll point to certain innovations. So, basically I observed that animals with focusing eyes, eyes with lenses, that are of a single compartment, not, you know, ommatidia, not the multi compartmented eyes of other invertebrates, but true focusing lens, single compartment eyes, camera eyes, in the case of the octopus, they seem to exhibit more flexible behaviors than other members of their phyla. Generally speaking, distance vision is possible in these animals via focusing camera eyes. So arguably, if we're talking about the back end, how these animals process what they're seeing, they have the luxury of time. Now, time becomes very important in terms of encoding this aspect in the nervous system. Because now if the animal can see stuff from far away, let's say the animal sees a predator from far away, maybe the predator hasn't seen him yet, he's 150ft, 200ft away. The predator hasn't seen him, but the octopus sees the animal, he's not going to react quickly, instantly, perhaps reflexively, as some people might say. So, arguably there's time now to plan to monitor the situation, to monitor the environment and act on salient events or objects within this detailed scene that the animal now is privy to with his focusing eye. That gives him the capability of distance vision. Distance vision necessarily evolved with brain circuitry for monitoring and predicting. I think, excuse the expression, I think that's a no brainer. I think that that must have been the case. I think distance vision paved the way for the elaboration of new kinds of memories. We talked about working memory. Eventually, we can talk about episodic memory because now we're talking about rich visual scenes. And you have to sort of, you know, you have to sort of think that it's, it doesn't make much sense for the animal to have this sophisticated perceptual capacity without the ability to store all that detail over, over sort of longer stretches. And now we can say that animals equipped so equipped were able to construct detailed visual scenes. They had various submodal properties. When I say submodal properties, in the case of the eye, I'm talking about textures, contours, intensities, wavelengths. Mapping these kinds of properties led to the development of certain kinds of specialized brain architecture and the means of integrating aspects of that architecture. Okay, so that is part and parcel of the link that I'm proposing between perception and memory, but it's also links within structures that are functioning like cortex. So, links between areas that are essentially memorializing different aspects of the world from different senses. So that's higher order mapping. It's arguably dynamic, which is to say that there is signaling going on all the time. It's not just simply sitting there stationary like a computer memory. Now, the binding of unitary visual scenes and the appearance of these new kinds of memories and the emergence of the reentrant or recurrent circuits that connect perception and memory, I believe are essentially the sine qua non of early sensory consciousness. 

And with that, I'm going to end my talk. I have a lot of people to thank. I'm sorry, I went over. I hope there's time for some questions. 

I really appreciate your time. Thank you very much.

Kate Armstrong

Fantastic. It's obvious why octopus is so, so popular in our audience.

David B. Edelman

Is everybody muted?

Kate Armstrong

Yes. Can you hear? Yeah, perfect. If you stop sharing. Okay, very exciting. Thank you very much for this, this talk. David, can you hear me?

David B. Edelman

Yes. Now I can hear you.

Kate Armstrong

Fantastic. Yes, it's obvious why they're so popular because I think it's fascinating. We just have so much content in, you know, 45 minutes, one hour. So, absolutely fantastic! I'm sure there are some questions to kick off a discussion. Who, who would like to begin? Do we have any, anything anybody would like to discuss straight up with David at the talk?

Kate Armstrong

Any discussion topics, questions? We did have some.

B

Excuse me.

Kate Armstrong

Go ahead.

B

Yes, I don't have a topic related question, but I mean it was quite a lot of information in a short time. So I'm wondering where can I access the recording of the session?

Kate Armstrong

Yes, we will put it onto the YouTube and you'll be able to re watch that so it goes onto our YouTube channel and we will do that within the week.

B

What kind of YouTube channel?

Kate Armstrong

I can share it in the chat for you.

B

Okay, thank you very much.

Kate Armstrong

No problem.

Diana?

Diana Reiss

Hi David. Thanks for a brilliant talk! That was so much information and fabulous. I had a couple quick questions. I just wanted to check two things. So when you're talking about working memory, are you distinguishing between working memory and long term memory? For example, when we talk about working memory in humans, we're talking about what we're using working is, you know, short term memory now called working memory. And then that gets… Some of that gets transferred into long term memory.

David B. Edelman

Right.

Diana Reiss

It seems from your, the experiments you showed, you have an animal with the. I'll give you a specifically when the animal, when the octopus was watching the other octopus coming in from the left to obtain that crab, was that done right before he was shown it or was there evidence for long term memory, as well where he's retaining it over time? I was curious about that.

David B. Edelman

So, in the case of those experiments, the actual presentation of the, you know, octopus who's sort of the trainee animal, the animal who's been trained on the, you know, with trials, trained on that task, the presentation of that animal who's already learned it to another animal who's watching. You know, that is, you know, these are, these are things that happen really sort of really quickly. So you, you show him that animal solving the problem and then you very quickly give him his own box. You drop a box like that. I should have explained that, I'm sorry. You drop a box like that into, into the new animals tank and instantly he goes to the right portal to get the crab out. Here's the intriguing part now, and I'll get lambasted by a lot of people for this, but when people talk about memory in regard to consciousness, they're quite, they think of memory in a very, very unitary sort of way. I mean, I'm not saying that they don't distinguish between working and episodic or long term memory. There is a distinction and I think episodic memory figures into what octopus, octopuses do too. I think both are going on in different contexts. But when people like for example, Christoph Koch years ago wrote a paper with Giulio Tononi where they essentially, they kind of all but disregarded memory, they shunted it aside and I thought to myself, hey guys, once a nervous system represents something, if that representation persists for more than a second, for four seconds, for a minute, it's memory. That is memory. Because the animal can revisit, even if it has to happen in short order, it can be revisited. That's a form of memory. And I do not believe, and again, there are some people who may, you know, crawl down my throat for this. I don't believe you can segregate consciousness and memory writ large, all of memory. But yeah, there is a distinction. You're very right and I should have, you know, made that distinction. But good point.

Diana Reiss

I mean, but it's, it's still fascinating to be able to see observational learning and the use in that time frame. I'm not saying I think that, oh yeah, these are really important experiments. It's interesting to find out if you delay that slightly, you know, like if you do a delayed match to sample, how long might they retain that? You know, it's, it's really curious. Does it get encoded into long term memory? That would seem like a natural experiment, even delaying it, you know, 15 seconds and then going 20. You could do those incremental measurements.

David B. Edelman

Absolutely. You're warming the cockles of the late Mortimer's heart. That is absolutely critical. And I would love to see somebody do a systematic series of delayed match to sample or delayed non match to sample. I mean, a whole suite of those would be really informative in the octopus. Thank you.

Diana Reiss

Thank you, David.

David B. Edelman

Sure.

Kate Armstrong

We have two other questions in the row, I think. H. Diter, you are next.

David B. Edelman

Theklas. Yes.

Theklas

Yeah, yeah, yeah, that's me. Thank you very much.

David B. Edelman

Thank you.

Theklas

Excellent talk. I really enjoyed it. Thank you very much for that.

David B. Edelman

Thank you.

Theklas

I do worry a little bit about what Chalmers calls, of course, the hard problem, which is we don't seem to really know as yet what the neural basis is for awareness or sentience. We can talk about correlates, of course, but given that we don't actually know what the actual neural basis for awareness, pure awareness is how safe are we in talking about cutoffs in terms of who has it and who doesn't have it? So I, I really appreciate you advancing ideas about how it evolves or how it evolved. It makes a lot of sense to me. There are a lot of ideas obviously about the evolution of consciousness, but in terms of who has it and who doesn't, it seems to me that's a trickier question. If we don't really understand the essential basis of awareness itself, what is your thinking about that?

David B. Edelman

I think, I think I, I largely agree with you. I think there is a big problem here. And part of the problem has to do with the fact that, you know, like essentially all sort of physiological brain properties, it's, it's a dynamic property or dynamic series of properties. And therefore, you know, we're not really privy to any kind of detailed sort of picture of all of that unfolding. Right? 

So, that gets to sort of technical limitations, technological limitations. If we talk about sort of state of the art brain imaging, what are we talking about in the case of humans? We're talking about FMRI, right? Well, FMRI has very distinct spatial and temporal limitations. It can only tell you so much. And it is not a direct record recording of nerve cell activity. It's recording of the metabolism required, changes in metabolism, required for hungry nerve cells. Right? Hungry neurons! So, arguably the neurons that are most active are going to be the neurons that are most hungry. And therefore you're going to see, you know, oxygen glucose levels elevated in those particular regions where neurons are sort of most responsive. So that's your picture from FMRI. It's not bad, but it's not giving us a real take. And temporally it's not great because of course it takes probably just shy of a second to reconstruct, for example, a slice of human brain in an MRI scanner. And that second is sort of a universe of potential activity that sort of falls between the cracks. It doesn't get picked up. So, we're not at a point where we can really pick this stuff up. So, I agree with you and I think there is an important caveat here that we haven't really picked up. We've picked up certain physiological signatures which are contemporaneous with conscious experience, in the human case at least, and we've correlated them with accurate verbal report, which is great! But as you said, we don't have a good feel sort of structurally or across sort of the functional Architecture of brains for what is actually what consciousness actually is at the level of, you know, sort of the. The physiological picture, you know. We don't know what's quite. What's going on there. So, yeah, it's an important caveat. And I, you know, I'm always mindful of it, you know, but I'm going on the idea, when I look at cephalopods, I'm going on the idea that if we identify certain other sort of strains of evidence, the more strains of evidence that we have, the better. So we can build an argument based on a lot of the behavioral aspects, what we observe behaviorally. We can build that argument also on strands of evidence coming from physiology, like, do we see physiological signatures that are reminiscent of sort of different frequencies of brain activity in the case of the vertebrates, do we see something similar in the octopus? You know, so I do agree with you, there is an important caveat here, and that is the limits of sort of what we can see and do right now. So, yeah, I'm very mindful of it. Thank you. Thank you.

Kate Armstrong

Thanks for the question. We have Eliot in our next question.

David B. Edelman

Hi, Eliot.

Eliot

Hi, Dave. Nice to see you again. I was privileged enough to work with Dave on the Barnes Maze is way back when.

David B. Edelman

Yeah.

Eliot

But my question is, I'm not sure if you've read it, but there's an article in the Journal of Experimental Biology of molluscan vision in the strawberry conch where it has a similar camera eye.

David B. Edelman

Yeah.

Elliot

I wonder what the obstacles would be to looking at the brain structure of a shelled mollusk versus a cephalopod.

David B. Edelman

Yikes. Yeah. I think there are sort of major constraints based on how invasive you would have to get. Right. You know, for example. Yeah. Well, you could argue that you could sort of drill through shells. You could do any number of things, but that is predicated on the idea that you can sort of map the structures behind that hard surface. Right? And know where you're headed. Very, very tough! I mean, probably somebody's going to do something like that along those lines eventually, but it's very, very tough at this point, I think, methodologically, to pull that off right now. 

I mean, it would be very informative. Right. Because you'd want, you know, if you're looking across phylogeny, you certainly want other comparators. You want to look across species to sort of see whether certain presumptions that you made regarding the octopus versus, say, vertebrates are kind of in line with some sort of A larger evolutionary picture. Good question. I don't know where we can go at this point, but I think it would be fruitful if somebody could figure out a way to do it. But it would be really, really invasive and a lot of trial and a lot of error, I think, unfortunately. Oh, and one thing I didn't mention, sort of off the subject, I should have mentioned it. Very, very recently something very interesting happened. There was a preprint put up by Judith Pongar and her colleagues that suggest the existence of sort of center surround visual fields in the octopus brain. That's extraordinary in the sense that that is the first indication of any, to any degree that they're doing what I described before. They're doing. They're mapping visual space in a way that's sort of similar to how vertebrate brains map visual space. That they're preserving the space, you know, that comes in from the input. Somehow in a part of the brain there's spatial, there's essentially topographic mapping. There's a topographical representation of what's on the outside, on the inside. That's really intriguing and I'm very gratified to hear that. I had an argument with somebody many years ago who made a strong claim that in fact there wasn't any kind of topographical representation in the octopus brain at all. But here we are. I think we have evidence for that.

Kate Armstrong

Our next question. I don't have your name. I only have the name of your device. So I have GigaSet GX 290. Or maybe this is your name. I'm assuming things. Awesome. I don't hear you though.

Jonas

I'm so sorry.

Kate Armstrong

Oh, now we hear you.

Jonas

I didn't check. I didn't check.

Kate Armstrong

It's not a problem. Now we hear you. Go ahead.

Jonas

Now you hear me. Okay. Good evening. Jonas is my name. Thank you. Thank you, David, so much for your talk. It was absolutely amazing and inspiring. Have you heard of David of Pena Guzman? He wrote a book about dreaming animals. Took in a philosophical approach, but that was pretty amazing I think, because dreaming… And you were talking about representation in animals and that would be a path to consciousness. And David Penningus man said that dreaming might as well be a strong indicator for consciousness. So do you know anything about dreaming in octopuses?

David B. Edelman

I know that we've had some degree of sort of behavioral evidence for something that looks like, looks like it might be dreaming. You see something like a sort of a form of a REM state in octopus, right? So rapid eye movement in the vertebrates, but you see something like that in octopus that have very high thresholds of arousal, right? So, they're or higher thresholds of ratio. So they're clearly sleeping. But something else is going on because you'll see sort of weird body patterning occurring in these animals. Their chromatophores are expanding and contracting. They're exhibiting these weird patterns during their sleep. And people have interpreted this as dreaming. We don't have, you know, sort of super firm evidence of that yet. I think dreaming is really, really an interesting aspect of brain function and some people have suggested, and I think I'm in line with this, that dreaming dream states are essentially a form of. They're a form of conscious awareness. But the difference is, you know, in the case of the mammal, the cortex is talking to itself. By and large, it's no longer talking across that re-entrant link to thalamus, right. So the sensory world isn't really coming in. Essentially the brain is sort of involuting and so aspects of the cortex are re. Entiently connected. They're recurrent, connected recurrently and they're actually doing something, but it's something on the inside with no recourse to the outside world. So it's the brain sort of talking to itself. It's the brain being sort of aware of stuff coming up from the, the memory reliquaries of the cortex. So, a lot of people would argue that consciousness is simply a different or excuse REM sleep is a variety of consciousness. And I don't think I disagree with that. So that's about the extent of it for me. I wish I knew a little bit more, but it's a great area.

Kate Armstrong

So thanks, Jonas. I'm. I'm conscious of time. So we're going to start going quickly through to the other questions of. Carol, if you wanted to ask your question.

David B. Edelman

Hi, Carol.

Carol

Yeah, I'm not sure I can even get the question out straight, but I'm fascinated. And the reference to chromatophores and dreaming is kind of apt here because from what I've read, octopuses don't have the capacity, like the visual capacity to even see color. And yet they've got the capacity to match up those chromatophores to the environment and the color. And to me that begs the question of what you mean by consciousness because in some sense that animal is conscious, is responding, is, you know, has the plasticity to respond to the environment at that point. But, you know, the idea that it has any even the visual response or the awareness that it's doing that like it.

I don't know how… I mean, this is a much broader question. But you know, I'm just curious about how you think about it. You know, that issue of awareness, consciousness and sensory input, perception, the whole.

David B. Edelman

Right, right. Well, well, let's just, just keep in mind, I mean, I'll just put this out there. Keep in mind that even though octopuses have more or less, as far as we know, in their eyes, less. One flavor of photoreceptor, right. They're, they're sort of sensitive to the blue range of. They're producing, their brain is building a complex picture of a visual scene. It doesn't need, it doesn't need the representation of what we call color, of wavelength, wavelength differentials to necessarily come up with a complex picture of the world both from near and from far away. So that's sort of a separate thing. You're talking about sort of a richer, maybe a richer variety of consciousness with perhaps true color vision. But you bring up an interesting point which is the mystery of color matching in octopuses. The idea that they only have this more or less one flavor of photoreceptor. They also, there's also evidence that they have some expression of this photoreceptor on their skin, which is sort of interesting, a sort of a photoreceptor on their skin. So they may be picking up information from that. We don't completely understand it. The idea of color matching is still quite mysterious. Some people have associated with the fact that octopuses also have polarizing vision. So they can see polarized light. And maybe some. And I don't, I don't necessarily buy that. I don't completely understand polarizing vision myself, but I don't necessarily buy it. But some people have suggested maybe they're making discriminations in a polarized light channel that are allowing sort of more sophisticated discriminations in terms of. I'm not sure that's the case. But yeah, you point to a long standing mystery. I wish I had an easy answer. But again, building a rich picture of the world isn't necessarily contingent on having sort of true color vision as we understand it. Although clearly the octopuses are responding to something that enables them to match colors. And I don't know what, I don't know what to say about that at this point. Roger Hanlon…

Carol

Yeah. You can't assume that because you don't see the color receptors. I mean, in fact, what you can assume is that the octopus is aware of color, but in some other. It's got a different type of way of responding to it.

David B. Edelman

Well, you know, again, I won't, I'm not going to naysay what you just said. I don't disagree with it, but I'm going to kind of become down on, more on the agnostic track. And basically we don't know whether they're aware of it, but we know that they can do something with it.

Carol

But I guess the question underlying that question was given that that is the case, there could be a lot of, I guess that issue of how much is happening in a sense outside the octopuses. So much of what happens in the human brain is happening right out of our consciousness, of course, you know, so the same could be said for the octopus. And it does beg the question of what exactly you mean by, you know, consciousness sitting on top of a much broader range of aware responsiveness.

David B. Edelman

Well, right. This is why I take great pains to link perception and memory. Memory is really critical to this equation. When you take memory out, it's pretty easy to sort of say, oh, okay, you can have a bunch of responses. You can have. I won't engage in antiquarian 1920s talk about reflexes or reflex arcs or that ilk. But you know, animals can do some really sophisticated things without any, you know, evidence that they're sort of aware. Right? They're doing. They can, they can even make certain kinds of discriminations which are pretty sophisticated, not without necessarily being aware. So, yeah, I know I haven't answered your. I haven't answered this in a completely satisfactory way, but just suffice to say that, yeah, that introduces a fly into the ointment, but I don't think it necessarily kind of hinders the direction I'm going in.

Carol

Right in how you thought about it because I find it hard sometimes to parse the questions themselves because of underlying easily like things that I find easily confusing.

David B. Edelman

Absolutely sure. Yeah.

Carol

Thank you.

Kate Armstrong

Thanks, Carol. Ken, your next.

Ken Rinaldo

Yes, thank you, David. Brilliant talk. If I could just expand the conversation to say that for me, any living creature is conscious, including a tree. In David Haskell's book the Song of Trees, distributed consciousness indeed. The proteins that we vertebrate animals use to create an electrical gradients and liven our nerves are closely related to the proteins in plant cells cause similar electrical excitation dating back nearly a year of memory. That helps the tree to know when winterize its cells, plant memories can cross generations as the offspring of stressed parents inherit an enhanced capacity to generate genetic diversity when they breed. Even if this next generation experiences benign conditions…

David B. Edelman

Sure.

Ken Rinaldo

… Chickadee birds. Distributed consciousness itself are the dreams of trees. And I just want to say that any living being must and has to be conscious in some way and form. So still wonderful to focus on the octopus eye. And thank you for this absolutely brilliant talk.

David B. Edelman

Thank you very much. Thanks.

Kate Armstrong

Thanks for your contribution, Ken. Thank you. Okay, Malcolm, you're next.

David B. Edelman

Hi, Malcolm.

Malcom

Hi there.

Dr. Edelman, is it?

David B. Edelman

Yes. Okay. David. David's fine.

Malcom

I was going to ask the question about the octopus's color vision and I might also add from a old time photographer's point of view there, There were video tubes that they were only sensitive to cyan and yellow and not to magenta, but they interpolated the magenta when there was an absence of cyan and yellow. So maybe the octopus is doing something like that to some extent.

David B. Edelman

That's really an interesting observation. And I think that also hearkens back to the work of the great Edwin Land, you know, inventor of the Land camera, founder of Polaroid, because he had a lot to say about this and he came up with an argument with a theory really that in fact animals, you could achieve color vision with only two, two sort of flavors of photo. It was sort of an interesting argument. It didn't, it didn't get very far in terms of time. You know, not many people sort of remember that argument. But he was a smart guy. He talked about this a lot. And I think what we've barely scratched the surface in terms of understanding how wavelength differentials are discriminating discriminated in nervous systems. So we have a long way to go. So. But yeah, that's a good observation. Yeah.

Malcom

I also want to make the observation. Most of my experience has been with the bottlenose dolphin. And I'm afraid that octopus is just pale in comparison. I mean, yeah, they're smart for a relative of the clam, I'll give you that.

David B. Edelman

Very smart relative.

Malcom

I think they just have a few behavioral tricks up their sleeve. There's no evidence of cooperation I've seen between octopus and octopus.

David B. Edelman

Right. Well, yeah. That's true. I mean, octopuses traditionally are sort of known writ large. They're known as sort of asocial animals. Although, you know, you have folks like Peter Godfrey Smith... Well, yeah, yeah, some do. But the point about it is, you know, while they may be sort of asocial, I'm really, really careful about parsing sort of richness of sort of cognition, cognitive capacity, and, you know, sort of parsing into a space in which we can only talk of sort of about social animals. Clearly that, I think that's an old rubric and I think we have to be really, really careful about that, extending that broad brush. Clearly, social animals have in large part a degree of complexity, neural complexity, behavioral complexity, certainly neural complexity, physiological complex, that is well above other animals in most cases. But we do have to be careful of sort of just saying, okay, anything that isn't social per se or that we can't observe as sort of regularly social. And I'm very careful here because I don't think we've totally exhausted possible observations of behavior in the wild. When it comes to cephalopods, there may be certain things that we haven't seen yet, although we've seen a lot.

Malcom

As I pointed out, a lot of the charm of octopi or octopuses lies in the fact that most of them are smaller than we are. As soon as they get to be a reasonable size in comparison to us, they become a danger. And I really don't think the octopus cares, whether it be frenzy or eats you, you know, you're good either way.

David B. Edelman

I'm not even. I'm not going to go there, but I know. I appreciate it, you know. Yeah. I mean. Point well taken. Thank. Thank you very much.

Kate Armstrong

Thanks, Malcolm. I think we're going to go to our final question and I think, Jennifer, it's a good one because it's coming from Jennifer, who's also spoken with us in our. In our community about octopus. I think this is a really nice moment to finish on. Thank you, Jennifer. Great to see you.

David B. Edelman

Hi, Jennifer. Oops, I can't ear you. Oh, there we go. Okay.

Jennifer Mather

I wanted to back up David in something that he said when he was talking to Carol, which is that we know that octopuses don't have color vision. They don't. They've only got one photo pigment, but they can discriminate the plane of polarization of light. And there's an awful lot of information going on in that particular dimension.

David B. Edelman

Right.

Jennifer Mather

We don't understand because we don't have it.

David B. Edelman

Absolutely, absolutely. I think that's super important. Yeah.

Jennifer Mather

That's what I wrote about in my review paper on perceptual richness, about the richness of the perceptual repertoire of an animal that doesn't have the same richness as us.

David B. Edelman

Exactly. Yeah, yeah.

Jennifer Mather

Which makes sense.

David B. Edelman

Oh, absolutely.

Jennifer Mather

And I think, okay, this is something a philosopher would say, and I might not because I'm a biologist, which is that the matching only has to be good enough.

David B. Edelman

Exactly. We, we miss this all the time in all of biology and in, in, in evolutionary biology in particular, we've been really guilty of talking about sort of matches as if they're, they're perfect, you know, matches in the world and they're not, you know, they, they never are.

Jennifer Mather

Yeah, but they don't have to be.

David B. Edelman

And they don't have to be. And, and I'll hearken back to an example that I think backs up what you just said, which is the immune system. And, and that's something near and dear to my heart because my late dad was, he started his, his career as a scientist, as an immunologist, and he was the guy who basically confirmed the idea that the immune system was a selectional system that essentially antibodies weren't coming up to antigens, to pathogens and perfectly matching their protein confirmation to those antigens. They didn't have to, they had a repertoire and there was a fit between a pre-existing antibody and the antigen. But the, the fit was never perfect. And that built in strength, built strength into the system because it meant that that antibody could actually also bind to other antigens which might have been something slightly different. And I think that holds for even this observation, which is far flung, you know, it's far a field of the immune system. It's a very important idea. That match isn't perfect and in fact systems that are more flexible are built on matches that aren't perfect and that lends greater strengths to those systems, I think. Just my opinion. So very good, very good point. 

Thank you, Jennifer.

Kate Armstrong

Fantastic. Thank you, Jennifer. And thank you, David. 

This has been a really, I think such a dense talk and I will make sure to try and get it up onto the YouTube channel as soon as possible because I think that everybody will want to be going back through that. The other thing I'll mention, I'll put it in the chat now, is that we do have a lot of references and Jennifer, you also just referenced a paper that you had recently that you had written. So, if there's anything that you wanted to share, you can also pop them into our Slack channel because there we can, we can all access them. So, I've popped that again into our chat if anybody would like to join that channel and there we can share some of the references from today as well. So this has been really fruitful and I think everybody's going away with their heads really full. I think there's questions, there's comments, there's all sorts of extra reading that we're all going to do. 

So, thank you, David. It's been really wonderful. And thank you, everybody for joining. We will see you at our next session, which will be happening in one month's time. So, we'll be doing this in the final weekend of April. We look forward to it. So, thank you so much for joining us.

David B. Edelman

Thank you, everybody. Thanks so much. Have a good day. Take care, you all. Bye.