Abstract: Among all invertebrates, the coleoid cephalopods—that group of molluscs which includes octopuses, squid, and cuttlefish—have by far the largest and most elaborate nervous systems. In addition, these animals have eyes that in many ways resemble those of vertebrates, albeit with some notable differences (e.g., one type of photoreceptor, no retinal ganglia). Moreover, the coleoid cephalopods—particularly the octopus—appear to be capable of both seeing moving objects such as predators and prey at reasonably great distances and executing a variety of adaptive behaviors in response to what they see. Such observations suggest: 1) the presence of relatively sophisticated visual processing, i.e., neural circuitry that can support dense visual input; 2) the possible specialization of sub-modal visual areas in the central brain, perhaps analogous to the vertebrate case; and 3) spatiotemporal properties of memory that would necessarily involve rapid integration of visual information into a dynamic 'scene.'
Here, I will argue that, on neuroanatomical, neurophysiological, and behavioral grounds, the octopus in particular represents an excellent model for investigating the possibility of conscious states in an invertebrate. In making this argument, I will: 1) lay out a working definition for consciousness that may be extended beyond the vertebrate case; 2) describe structural and functional properties which may be the sine qua non of sensory consciousness; 3) suggest evolutionary trends (e.g., the emergence of complex vision) that may have set the stage for the advent of conscious states in a variety of phyla; and 4) discuss my ongoing work and offer a 'roadmap' for additional experiments that could lead to a robust methodology for the explicit investigation of sensory consciousness in these, and perhaps other, invertebrates
Identifying Hallmarks of Consciousness in Non-Mammalian Species
Criteria for consciousness in humans and other mammals
Animal consciousness: a synthetic approach
Gerald Edelman "Wider than the Sky: The Phenomenal Gift of Consciousness"
Hochner, Shomrat & Fiorito (2006) The Octopus: A Model for a Comparative Analysis of the Evolution of Learning and Memory Mechanisms Biol. Bull. 210: 308–317
Borrelli L, Fiorito G (2008) Behavioral analysis of learning and memory in Cephalopods. In: Menzel R, Byrne J, editors. Learning and Memory: A Comprehensive Reference. UK: Elsevier. pp. 605–627. (PDF will be provided)
Comments invited
Dr. Edelman's examples of octopus behaviour were fantastic, and his stance that octopi share certain hallmarks of conscious activity are certainly striking. One example, however, seemed to point to a hard-wired, innate reflexive system of vision/action, rather than conscious 'thought' per-say: his octopi subjects were able to recognize both CGI and dot-animated crabs as real crabs, carrying out their 'crab-attack' on these crab-like forms, just as they would for any other real crab prey.
ReplyDeleteWhile Dr. Edelman used this to illustrate a complex visual recognition system, I believe this points to a rather more primitive representation of prey. The octopus has no stored visual memory of a crab - just a rough program wherein a crab-like form, or crab-like movements trigger the attack response.
As humans, we recognize a dot-diagram in a roughly human shape is being semblant of a human, however we would never approach this dot diagram and try to have a conversation with it (or attack it for that matter...), as we have access to the higher order knowledge of what constitutes a 'real' human.
These differences seem to point to an entirely different mechanism of representing 'other' in the octopus.
But, as was mentioned in the discussion panel today, it is important to form non-anthropocentric definitions of consciousness, and accomodate species-specific definitions of consciousness where needed.
I believe that Thomas Nagel's "what it is like" to be a given being/organism could be endorsed as a sufficient condition for a being to be considered as having phenomenal consciousness. If there is something it is like, subjectively, to exist, or to act in a particular way, or to perceive the crab (in the octopus'case), then we would be talking about phenomenal consciousness.
DeleteThe great advantage of this definition is that it is not anthropocentric (every being can have its own way of feeling "what it is like" to be itself, as long as they have one). Saying that in order to count as being phenomenally conscious a being just has to have something it is like (to himself/herself/itself) to be in such a situation, doesn't seem to involve any form of species chauvinism.
This of course doesn't solve all the problems (in particular epistemological problems about how to know whether there is something "it is like" for an octopus to see a crab - it could be an octopus zombie!), but at least seems to be a relatively safe definition of what phenomenal consciousness is.
Telencephalon certainly makes a fair point: the reactions of octopuses to the presentation of an actual crab or a CGI 'simulacrum' may simply be hardwired, optomotor responses. The case of the point-light crab, which was devised for the 'perception of biological motion' experiments, is almost certainly an instance of a response that is also hardwired (as are examples drawn from the vertebrate literature), albeit somewhat different in nature than the other cases. But, the point of these examples was not to provide evidence of consciousness in the octopus, but rather, to demonstrate the efficacy of a psychophysical approach in investigating the properties of visual perception. In the future, such an approach could fruitfully be extended to experimental designs relevant to the investigation of consciousness, i.e., an 'attentional blink' experiment or the like. Along these lines, he combination of a video-based psychophysical approach with multi-site LFP recording in a free-behaving octopus would be quite potent indeed.
DeleteTo Telencephalon: Yes, ethologists already showed with stickle-backs that the "cues" for mating and fleeing are just that -- stimulus patterns, not necessarily the whole organism.
ReplyDeleteNagel's "what is it like?" is really "what does it feel like?"
What makes a mind a mind and a mental state a mental state is that it *feels like something* to be a mind, and to be in a mental state.
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DeleteI agree with Stevan when he suggests that Nagel's "what it is like" could be better understood as "what does it feel like".
ReplyDeleteWhat I wanted to stress was that the interesting feature of this definition is that it does not set any specific qualitative species-relative treshold for "how" something has to feel like: it is sufficient that it feels like something to the being in question.
As long as there is something it is like for a bat to feel "qua" bat (say - via its echo-locatory senses), that bat is "bat-like" conscious. Similarly, as long as there is something it is like for a human to feel "qua" human, she is "human-like" conscious. And so on and so forth. Any being for whom there is something it feels like to be such being - following Nagel's definition - is conscious.
Prove that there is something it feels like for Dan's and Brooks' robot Cog to exist and I'll acknowledge it is Cog-like conscious (phenomenally conscious in its own manner, which will probably depend on its embodiment characteristics and so on..).
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DeleteI think that you [and Stevan] are definitely charting the right path here. Though I'm ambivalent at best about David Chalmers' take on Qualia (I believe that he might be confusing the properties of non-iconic, linguistic descriptors--which are very far removed indeed from sensory input--with the actual discriminations [or qualia] themselves), I'm certainly down with the idea of feeling being essentially the basis of phenomenally conscious experience. But, I'm still turning this around in my own mind...
DeleteEdelman commented that it was interesting that octopuses sometimes demonstrated social learning in a laboratory setting. If we find that this is true social learning (I realize Edelman was not claiming that it was), I ask: what environmental pressures favoured social learning in an organisms that is solitary? Since I can't think of any, I suggest that in this case, social learning is an epiphenomenon of some other cognitive processes.
ReplyDeleteCertainly, the position of most ethologists (and nearly all cephalopod researchers) is that social, or observational, learning would necessarily have appeared exclusively in social species. This is an understandable adaptationist position, i.e., many, if not most, behaviors evolved as a result of strong selection pressures imposed by ecological shifts. But, this popular view does beg two questions: 1) could observational learning be an epiphenomenon (as you suggest)?; and 2) do we know enough about octopus behavior to be sure that species such as vulgaris (in which FIorito and Scotto reported observational learning) are entirely asocial. Certainly, there is some anecdotal evidence (and, I believe, an ongoing study of animals in the Bay of Naples) that suggests a degree of sociality that was previously unknown. And I wouldn't dismiss the possibility that observational learning is an emergent property. So, I guess the jury is still out. ;-)
DeleteThank you for the reply!
DeleteDr. D. Edelman, I will be waiting for news about whether the octopus vertical lobe (analogue of hippocampus) exhibits any network oscillations!
ReplyDeleteWhen I set up my lab at Bennington College this coming Winter (I'll be leaving The Neurosciences Institute and TSRI and joining the faculty at Bennington next Fall), this is one kind of question I'm really keen to address. Though I can't promise any findings along these lines as soon as next year (or even by 2014, for that matter), please do stay tuned! The vertical lobe certainly looks promising, given both its overall architecture (see Hochner et al. 2006) and the effects of ablation surgeries on visual memory, as reported by Martin Wells, J.Z. Young, and others in the 1950s and 1960s. If a hippcampus-like function truly holds up for the vertical lobe, and, as you say, we observe familiar network oscillations in this region, then I think we'll have the beginnings of a good case for functional parsimony in brain evolution, to wit: there may be only one way to instantiate much of higher function (e.g., episodic and spatial memory, among others) in animal nervous systems, regardless of dramatic differences in gross morphology.
DeleteThis lecture was fascinating, I'm concerned with embodied cognition and octopus seems like an all-time enacting champion. How exactly does it feel to be an octopus ?, great question... How does it interact with its environnement considering his alien-like nervous system ? is another. I was thinking about the camouflage and I wonder how's that even possible considering octopuses are color blind.
ReplyDeleteOctopus camouflage and its attendant color- and texture-matching attributes certainly present a puzzle. There is a recent study, published in Current Biology, that suggests that polarizing vision offers a sensory channel allowing subtle contrast discriminations that map to fine color differences. Here's a link to a Scientific American blog describing the study:
ReplyDeletehttp://blogs.scientificamerican.com/octopus-chronicles/2012/02/20/polarized-display-sheds-light-on-octopus-and-cuttlefish-vision-and-camouflage/
And here's a link to the actual Current Biology paper:
http://www.cell.com/current-biology/abstract/S0960-9822%2812%2900011-5
Perhaps the foregoing sheds major light on the mystery of cephalopod camouflage in general.
I was also fascinated by the camouflage thing. Especially since MacIver pointed out the low light attenuation in water... Do octupi's predators rely on visual information?
ReplyDeleteAre there something like "sense-ecologies" in evolution? Isn't there something vaguely social about the predator-prey relationship?
All sorts of questions...
As you say, light is quickly attenuated in water, particularly at depths greater than a few meters. In any case, though, most octopuses are predominantly visual, and, I believe, so are their predators. Many--perhaps most--species of octopus, including O. vulgaris, are pelagic animals, and I believe it's at these shallow depths that camouflage plays a critically adaptive role.
DeleteI don't know that I'd classify predator-prey relationships as social--at least in the sense understood by most ethologists. I think that social relationships would generally be characterized as ongoing interactions among {though not necessarily limited to} conspecifics. By definition, predator-prey relationships are mostly one-time interactions.
Keep asking questions!
I was particularly struck by a feature of the cephalopod nervous system: the ganglia located in the arms. Is it possible to investigate the "arm intelligence" separately from the (CNS? Head brain? Not sure what it's referred to as in cephalopods) intelligence, say by anesthetizing the CNS while letting the arms remain functional?
ReplyDeleteI don't know that anyone has actually characterized [disembodied] 'arm intelligence,' per se. However, Benny Hochner's group at Hebrew University has studied extensively both central neural motor control of arms, as well as the nature of pseudo-autonomous movements (e.g., unevoked vs. evoked) in preparations of detached octopus arms. Check out the group's list of publications here:
Deletehttp://www.octopus.huji.ac.il/site/publications.html
The example of observational learning that Dr. Edelman showed us (an octopus learns how to open a complex box by looking at another octopus opening it) was very impressive. But Dr. Edelman mentioned afterwards that, although in the original study the octopuses were successful on every single trial, other experiments using a similar setting have been less successful. So I wonder: has anyone studied which factors influence the success rate in this experiment? This could lead to interesting hypotheses about the constraints on observational learning and eventually to a better understanding of the cognitive mechanisms underlie this capacity in octopuses.
ReplyDeleteI very much like this idea! I was wondering if this observational learning (such as the example of the octopus learning how to open a complex box by looking at another octopus opening it that Dr. Edelman showed us) has ever been observed outside laboratory settings? Would it be common, if it happened at all, that an octopus would watch another octopus and imitate it or learn from it? (considering they are not very social animals, from what I understand) What would be a more natural or common way octopi learn in nature?
DeleteIzabo Deschênes
Xavier Dery @XavierDery
ReplyDeleteUsing octopus vision as a portal to study consciousness in non-vertebrates... Does it sound amazingly interesting or what?!? #TuringC
3:49 PM - 30 Jun 12 via Twitter for Android
I wonder if the spatial architecture of the octopus brain would allow integration of information to the level of higher order thoughts or if functional connectivity and/or synchronization of the activity would be enough to enable such functions...
ReplyDeleteInteresting to come back to Dr. Edelman's talk after having heard, in particular, McIver's theory about the transitions from “collision mode” to “reactive” and “deliberate” modes of stimulus processing. In this new light, which is directly compatible with Dr. Edelman's strong emphasis on octopus vision, which greatly expands the octopus' sensory and motor spaces.
ReplyDelete