Dr. David Edelman
Last (though certainly not least!) in this series of interviews is Dr. David Edelman, a neuroscientist and co-author of the paper “Animal Consciousness: A Synthetic Approach” which discusses some strategies that could be used to study consciousness in all sorts of animals – cephalopods included.
After this weekend, I’ll be back to my normal, sporadic posting schedule. I have posts in the works on the Vibrio-Euprymna symbiosis, some new research that has just hit the presses on squid hearing, and the effects and possible utility of environmental enrichment in captive cephalopods.
I’ll not keep you waiting any longer! As usual, my questions are in plain text, and Dr. Edelman’s responses are in boxes:
Just to get readers oriented, what’s your background and what do you do (professionally and/or otherwise)?
I entered science really late. One of the reasons for that is that I’m the son of a pretty famous scientist, and I really had to think about whether I wanted to follow in the family business, and so I gave pause for a long period of time. By the age of 28 – really late in the game – I said “Well, you’ve got to do something, and science has always been your most important intellectual exercise since you could remember anything.” What I did, being an evolution buff even before my dad was, I started with paleoanthropology – I applied to graduate school in 1987 for some anthropology programs and got into the University of Pennyslvania in their classical sort of anthropology program. I was fascinated with the evolution of the human brain in particular, and I realized quite quickly that I wasn’t going to be able to bring evidence to bear to my satisfaction, by the very nature of what you have to work with [in paleoanthropology.] The best you can do is an endocranial cast, which gives you, if you’re lucky, good impressions of certain major sulci and divisions on the surface of the brain. That’s not a lot to go on. You’re talking about next to nothing. It wasn’t terribly exciting, and I didn’t know if I could build a dissertation on it. So I become a biomechanics person and I put together a project on the evolution of the internal architecture of the hind limbs of hominines and hominids.
The sad part of that era of my life is that where I went with it, or where I didn’t go with it, was dictated very much by the lack of good positions, and so I had to make decisions more or less on the fly. I did a postdoc in transcriptional gene regulation, which was really far afield, especially for someone whose working knowledge of genetics was as vintage as mine. My education in genetics went back to the early eighties, the stone-age of genetics – pre-PCR, even.
So somehow, I ended up at the Neuroscience Institute, and I’m still doing this. I segued into a project that was attractive in the sense that I would be working with living cells, with primary neuronal cultures. It was a way to get back to the brain, which appealed to me. Talking to people at the institute, it became clear that one thing that was not understood was mitochondrial dynamics in the nervous system – how the movement of mitochondria might inform the function of cells – in nerve cells, it might inform or even constrain the electrical activity. We were the first lab to show the link between mitochondrial movement and neuromodulation; specifically that a variety of neuromodulators, for example, serotonin and acetylcholine, acted as signals that effected mitochondrial movement.
The consciousness stuff has always interested me. It went way back to the time I was talking to my father about these things when he was formulating his ideas about consciousness. He’s now very widely published in this area, and his ideas are still very controversial In some circles, but they’re really what got me interesting in this in the first place. About 5 years ago, Bernie Baars became an associate fellow at the Neuroscience Institute and I got an opportunity to get to know him. After a lot of lunch-time conversations we decided to delve into the area of animal consciousness and see what sort of depths we could plumb. About 2 years ago, I started forming a friendship with Graziano Fiorito in Italy. The Stazione Zoologica is this singular institution where they might have 50 or more [octopuses] at one time available to do various behavioral assays on, so you can get very high numbers pretty quickly if you’re doing an experiment. That’s how the octopus project got started. The octopus is a great opportunity in the sense that after J. Z. Young’s work, except for Hochner in Israel and some of Graziano Fiorito’s work, there hasn’t been much in the way of formal neuroscience done in the octopus – this is a pity, but it’s also sort of an opportunity.
What we’re working on right now is a project where we use a back-projection video system to expose octopus to a variety of different video stimuli – salient stuff like crabs and moray eels – and also CGI animations of salient objects. We’re trying to develop a way to manipulate aspects of space and time in ways we can’t do with real images, so that we can slowly extract parts of the image to see what the salient parts are. The brass ring that we’ve been shooting for, since about a year ago, is to set up something that would be akin to an attentional blink experiment for the octopus. In reality, as much as we think of their eyes as being these wonderful examples of convergent evolution (which they are, in fact,) there are some differences between octopus eyes and vertebrate eyes, and we don’t know a great deal about the processing system behind the eye of the octopus.
We started doing these experiments and found that many of the animals didn’t respond to still images right off the bat, even still images of salient objects. We went through a period when we were doing trials where we would show the animals, say, a video of a crab moving where the crab would freeze for a second. Then we’d take a thirty second break, show an image of an empty tank, and then show another image of a crab, which would then freeze for a longer period of the time. At the end of a series of trials the octopus would be exposed to a still image of the crab, and most of the animals did then respond to the still image. We were entraining them to do that, and it was a pretty interesting phenomenon in itself. It was a strange result, and although it didn’t completely dash our hopes for an attentional blink experiment, it did put that on hold while we investigate more simple things. For now, we’re trying to elaborate on this toolkit that we started building about a year ago to test these animals, and I’d expect that the first publication based on what we’re doing now is not going to be out until at least next spring.
Why work with the octopus, instead of another animal?
As you might have gathered, I have a sort of a strange background in the sense that I have not studied animal behavior for a long time. I got into it a few years ago, stemming from an interest in animal consciousness that started about five years ago. Most of my work is at the molecular and cellular level, but I’ve been fascinated with the question of animal consciousness for the past five years and I just had to give myself some experimental chops. The octopus seems like such a savory entrée for this purpose. It’s an animal that represents a choice opportunity to test all sorts of ideas we might have about convergent brain evolution regarding certain kinds of higher functioning in animal nervous systems. Even if the nervous system is substantiated in an entirely difficult way in the octopus compared to the vertebrates (which it is, of course,) there might be functional principles that are adhered to in all such complex, heterogeneous nervous systems. If you wanted to test any invertebrate for what we might call consciousness, the octopus seems like a good bet, with about half a billion neurons in total and many hereogeneous brain lobes. It’s an interesting animal with a very sophisticated set of sensorimotor adaptations, which look like a very good set of constituent elements that would go into a potentially conscious system.
Why should people (scientists or non-scientists) care about research into animal consciousness?
I can understand the inhibitions that some of my colleagues have about using the term “consciousness”. You might say “I want, for the sake of my career and for the sake of contributing something substantive to neuroscience, I’m going to stick to something bite-size [in my work], say, decision-making correlates, or the role of the prefrontal cortex” – that makes a great deal of sense, and I can’t fault it at all. The simplest answer for me, though, is that essentially, if you’re going to take the next step after trying to understand, for example, the vertebrate visual system, I think it’s unavoidable. Conservatively, there are about 70 visual areas in the higher primate, and about half of the cerebral cortex is dedicated to processing vision; but if you asked me to tell you how it all comes together I really can’t say. That remains a great mystery. Well, I think one of the most basal aspects of consciousness (I shouldn’t use the word “basal” when I invoke the term consciousness, but I’ll do it on just this occasion) is the stitching together of either multimodal or submodal sensory properties into a unified scene and then stepping back and watching that scene in a persistent memory. That is the starting point for a conscious state, and if you’re interested in explaining how the world gets stitched together in the sort of heterogeneous nervous system that’s characteristic of higher vertebrates, and us in particular, consciousness enters the story. So if you’re interested in the final aspects of putting the world together internally into some sort of dynamic representation of the world – which is what brains do – and if you want to study the output of these systems with very dense sensorial input, it’s consciousness (at least in the case of mammals and birds, for sure, although don’t have that much to go on.) This is something that’s not very big in neuroscience right now, but I think that it’s one of the big and more interesting questions.
I think people are scared of it. For decades it’s been the purvue of philosophy, and, not to fault philosophers, but I think this has induced a lot of scientists to avoid the issue to begin with, and that’s a mistake. In my own mind, I’ve been trying for years to demystify the conscious process. The notion that you could bring together all kinds of submodal properties of vision and not do something with it that involves the stitching together of it into a coherent scene that is informative in some way seems counterintuitive. I think that eventually there’s got to be some sort of day of reckoning; you can divide up and parcel up aspects of perception all you want, but in essence, when you’re talking about visual perception and you’re talking about a mammal or a bird, you eventually have to talk about the output of all that. There’s no requirement that anybody study consciousness but eventually, sooner or later, especially as the spatial and temporal resolution of imaging technology improve, it will be something that people all but stumble over. A lot of the hesitation has to do with how people feel, how sanguine people are about their own definition (or adefinition) of consciousness, or whether they think that consciousness can be defined at all, but I think it’s inevitable. If you’re going to put together the whole picture, that’s what lies at the end of the road. We might be quite a far ways from it right now, but it’s something we’re going to have to confront sooner or later.
What sorts of projects would you most like to see done (or feel most need to be done) in the field of animal cognition and consciousness?
I think that in the case of animals, there are neurophysiological advances to be made. One thing that we haven’t gotten, even in the human case, is a series of well-defined reproducible experiments to determine all of the correlates of consciousness. I think that’s an area that screams out for some advancement. In the case of non-human animals, it gets even tougher. It’s very difficult to study, unless you’re talking about an animal like Alex the parrot who has pretty good linguistic faculties and can do a form of accurate verbal report, and right now, nobody seems to have a vested interest in doing projects like that. The real problems with animals who are going to help you demonstrate the correlates of consciousness is that, being complicated animals with complex nervous systems, they are a heavy time commitment. Given the way the system works, it’s not going to be easy to get NSF money over multiple years to get animals trained to go after those issues, even though they are paramount in the study of consciousness. That’s a bureaucratic problem, a problem of interest, a problem of priorities. If I had the wherewithal and the resources behind me, and the time, and the help, I would start dissecting the issue of consciousness in African grey parrots – they have this distinct advantage that once you teach them a nice lexicon of terms, they can give you something tantamount to report, obviating the problem that you have in the case of other animals in consciousness studies.
In the octopus, we may not get to the “big C”, but what we will do is attack some questions about the differences between visual perception in the octopus and visual perception in vertebrates, what visual salience means to that animal, and perhaps, if we’re really lucky, how that animal integrates submodal properties of vision or even properties of vision with another modality like touch. These are very rudimentary questions, but they’re important waystations on the path to studying consciousness.
Are there any popular misconceptions about consciousness or cognition, either in humans or in non-human animals that you’ve encountered? What are they, and what would you prefer that people thought?
There is one that has been brewing in my mind for a long time, which is the old idea that we only use a certain percentage of our brain – say, 10%. I love that! If you’re a fan of the idea of natural selection, or any sort of selective system, and you realize that nervous systems work by virtue of large repertoires of possible responses, it’s a silly idea. Any nervous system is going to be dense with all manner of possibility, and the environment or context is going to select out certain functional units to come to the fore in terms of representations of the world in the nervous system at any one moment. It’s a very difficult thing to convey to people, the idea that we shouldn’t consider the brain as this thing that is built from scratch, but consider it as first a repertoire of possible circuits, and then a repertoire of possible traffic-ways on those circuits that’s wired up during development. By virtue of the number of cells in the nervous system and the number of connections between those cells and their neighbors, there are myriad possible ways to represent parts of the world. It may sort of be true that if you look at the brain in terms of active states versus just noise, that it looks like only a certain percentage of the brain is active at a particular time, but you can’t scale the brain down to that momentarily active 10% and have a really well functioning brain.” You’ve just cut that repertoire by 90%.
Here’s another misconception; the idea that a brain is tantamount to a big computer. If you’re an interested, intelligent layperson and you read Discover, or the New York Times science section or something like that, you’ll come across articles talking about computers that are acting brain-like. For example, take Deep Blue – they put basically the entire history of chess into Deep Blue, and Deep Blue had the advantage that it could process certain things much faster than Kasparov could, so Deep Blue was going to win the chess game! But what you did there was put in a very rich but very specific set of historical information into that computer. Chess is just not a very good way to convince me that you’ve come up with a computer that is like a biological organism. This is symptomatic of the notion that’s being pushed even to this day that brains are very computer-like, and do very computer-like operations. They are doing processing operations, there’s no doubt about that, but they’re not doing it the way a digital computer is.
There are even a lot of people who are practicing neuroscience who, though they might not say this explicitly, portray the brain in their work and through the kind of language they use that, if one didn’t know better, one would believe that they are tethered to the notion that brains are merely another form of computer. But they’re not; computers just have been, like the technology of any given day, something that people fall back on to describe the properties of the natural world. Humans are very good at doing this – it’s a very convenient and facile way to render something that seems reasonable in one’s own mind as a model as what goes on in the real world. I think that’s the biggest misconception that I would rage against, if I had to: the notion of brain as computer.
Being a student, I’m interested in the process of becoming a scientist. Do you have any comments or advice for people who might what to pursue research in the area of animal cognition and/or consciousness?
Most of my advice is very practical. Research the graduate program you decide on really well, and talk to the faculty and some students from the program. Following from that, pursue somebody who’s a strong mentor, both in an intellectual and a practical sense. My graduate advisor at Penn was a very smart guy, he was very personable, and I liked him a lot, but he wasn’t an activist advisor. I saw around me, people outside of anthropology, people in biology, their mentor took it upon themselves to help shepherd that person out into the world, beyond simply reading the dissertation and suggesting things, really figuring out how to get that person ensconced or active in the career. This is very important and this is not necessarily that easy to get at, but you can sort of look at people’s track records and see who their graduate students were and what they have done with themselves, and that’s probably a fairly good indication of how active the mentor was in getting them out there. That seems like sort of far down the pipe for any potential graduate student to consider, but the more and more I think about it, the more I believe that that’s an important area to bone up on before you take the plunge.
Thanks for reading!