Here it is, finally: the post you’ve been waiting for. Having already convinced you that you should care about the possibility of consciousness in cephalopods in Part 1 and having briefly outlined the state of research on consciousness in non-human animals in Part 2, I’ll get right down to it and discuss the possibility of consciousness in cephalopods in this post. If you’re unfamiliar with the topic, I suggest reading Parts 1 and 2 of the series – in this article, I’ll be very brief with explaining some concepts that are explained in more detail there.

In this post, I’ll reference Jennifer Mather’s 2008 article (which I can’t recommend highly enough) “Cephalopod consciousness: behavioural evidence” and Edelman and Seth’s article (which is also an excellent read) “Animal consciousness: A synthetic approach”. These are both review articles, so I’ll be citing their descriptions of other people’s experiments a lot – I know this is bad practice, but hey, this is a blog – I can get away with it. I’ll cite a research study itself if I discuss it detail, but I’ll mostly be sticking to the arguments outlined in these two papers.

If you’ll remember from the last post in the series (and I’m sure you do, but I’ll summarize here anyways,) there are several methods that researchers use to get at the question of consciousness. Most directly, there is accurate self-report, whose use is limited to animals with whom we can communicate through language. This is not a useful approach with cephalopods, who (thus far) are not known to use language.

In the absence of language, animals can be trained to report on their experience (such as by performing a task for a reward when they detect a certain stimulus.) This approach is not well developed in cephalopods. Octopuses have been trained through reward and punishment to attack certain stimuli and not others in many studies; despite this, there is no protocol (that I know of) that to train octopuses with a task that would allow hypotheses about the animal’s awareness of its own experience to be tested directly in the ways that has been done for primates (for example.) Nevertheless, there is some evidence suggesting that cephalopods may be consciously aware from studies that use specific trained tasks.

Mather makes the point that the ability of cephalopods to learn a variety of tasks reliably and quickly, and then to forget them afterwards, makes them good candidates for at least primary consciousness because it implies the sort of behavioral and cognitive complexity that appears to be associated with consicousness in vertebrates. As an example of this, when experiments on visual discrimination in the octopus were done (mostly by M. J. Wells in the 1970′s and earlier,) experimenters attempted to discover the basis by which octopuses discriminated between two visual stimuli. In a sense, they were looking at how the octopus categorized stimuli. A number of hypotheses were generated to explain this within a simple, computational framework, but it was eventually concluded that octopuses (that is, individuals of the species O. vulgaris, the common octopus) don’t use a set of simple rules to categorize objects. Rather, Mather argues, they “[evaluate] a figure on several dimensions and [generate] a simple concept, where [a] concept is an abstract or general idea inferred or derived from specific instances.” Other evidence for the ability of cephalopods to exhibit learning like that taken to indicate cognitive ability (and thus the potential for consciousness) in vertebrate species comes from more complex learning tasks. The spatial learning abilities of cephalopods have been studied and it has been found, in general, that they might be capable of spatial learning to rival that of commonly used vertebrate laboratory species (such as rodents,) as long as the apparatus used is adapted to their capabilities (obviously, we cannot expect a rat and a cuttlefish to learn the same things in the same circumstance, but both can show impressive spatial learning given the right circumstances.)

Consciousness can also be suggested by non-trained behavior of an animal. As I’ll address at more length in a little bit, such evidence in cephalopods is found in accounts of their foraging behavior, their responses to novel objects in their environment, and the presence of sleep-like (and possibly REM-like) states. Most convincingly, in my mind, is the evidence suggesting the superior behavioral flexibility of cephalopods.

One of the more straight-forward tasks that is used to suggest conscious awareness in human and non-human alike is the mirror self-recognition task (MSR). What happens when you show a cephalopod a mirror – does it recognize itself, or does it treat its reflection as if it were another animal? Mather cites a personal communication suggesting that cuttlefish fail the MSR. You can see for yourself, in this great video of a cuttlefish at Epcot being shown its own image on an electronic screen. It turns very dark and pursues its image as if it were confronting another cuttlefish. The mechanics are a bit different, but it’s essentially similar to the MSR:

Mather makes a case for the cognitive abilities of cephalopods using the results of a study that looked at the strategies that octopuses use to open bivalves (which she discusses in this interview on Scientific American.) Not only do octopuses use different techniques for opening clams of different species (that is, they pry open the shells of the weaker ones, and drilling holes through the shells of the stronger ones, but they could switch strategies if one wasn’t working properly. When the experimenters took the clams that the octopus normally ate by prying open and wired them together so that they couldn’t be opened, the octopus figured this out and started drilling. This sort of behavioral flexibility, particularly the selection of one possible behavior among many on the basis of its effectiveness in a specific situation, could be attributed to some sort of centralized “executive processor” that might associated with consciousness.

Although definitions of “play” are often disagreed-upon, Mather argues that some octopuses have been observed playing with objects. While the existence of play behavior in a species is not indicative of consciousness, it suggests the possibility of consciousness; object play is, as Mather says, “something that intelligent animals do” to allow them to learn about things in their environment. (You can read my discussion of one study of octopus play at this link.)

It has also been (rather famously) argued that some octopuses have evolved the ability to use tools – specifically, one species of octopus (Amphioctopus marginatus) has been seen carrying empty coconut shells across the sea floor, which they use as mobile shelters. It can be argued that tool use is only possible when the animal using the tool has developed some rather sophisticated cognitive awareness of their surroundings that allows them to appreciate how an object can be used for a certain function. Here’s a video of this behavior, taken by one of the authors of the 2009 paper on the subject:

The comparative neuroanatomical argument for consciousness (epitomized by Panksepp’s “triangulation” approach to the problem, which recommends using affective, behavioral, and neural approaches together to infer consciousness in non-humans) is much more difficult to make for cephalopods than it is for vertebrates. The reason for this is simple: humans are vertebrates, and share many features of the anatomical and functional organization of our brains with other vertebrates. If you dissect a rat brain and a human brain side-by-side, most of the parts in one of them will show up in the other one in some form. Thus, it is rather easy to make an argument from analogy claiming that, because the brain activity and behavior of the two species in some situation are similar, it is likely that their experiences are likely to also be similar. It is harder to make this argument between people and cephalopods, because there is no direct equivalence between any of the parts of a cephalopod brain and the parts of a human brain, with the possible exceptions of the retina and primary visual processing areas of the two species and some parts of memory systems (eg. the vertical lobe system in cephalopods and the hippocampus in humans.) Even these are examples of convergent evolution (meaning they started from different places and got the same functional result,) and so the equivalences between these two brain areas in cephalopods and humans are only approximate, and based on a very limited knowledge of the functions of the cephalopod brain. Despite this difficulty, there are some overall features of the cephalopod brain that suggest consciousness, including its apparent organization as a complex integrator for sensory information, its lateralization, and its patterns of activity during sleep and wakefulness.

Edelman and Seth argue that we have a good reason to suspect that birds have some sort of consciousness, based on apparent anatomical and functional correspondence between the brains of mammals (including humans) and birds. They show this figure, which illustrates this correspondence – it shows diagrams of a human brain and a finch brain, with homologous structures colored similarly in each diagram:

As you can see, human and zebra finch brains (and indeed, mammalian and avian brains in general) have somewhat similar layouts, which allows one to make an argument for the inference of similar subjective states that correspond to certain types of neural activity in multiple vertebrate species. The basic logic is simple: if the brains are similar, and most of the output of the brain (that is, behavior) is similar in a certain situation, the rest of the output of the brain (that is, affective and/or conceptual awareness, eg. consciousness) is reasonably likely to be similar.

At the bottom of the figure, though, they show the octopus brain. Notice that it’s done in a completely different color scheme. This is because the functional or anatomical subunits of the octopus brain are not clearly equivalent to those found in vertebrate brains. A few localized functions of the octopus brain can be compared to those of vertebrate brains – for one, the vertebrate retina and the octopus optic lobe have apparently analogous structures and functions (that being the initial processing of visual information,) and the vertical lobe/medial superior frontal lobe system of the octopus is known to be involved in memory consolidation, and may have a microscopic structure that resembles that found in the mammalian hippocampus (for more info on this, check out Young, 1991, who makes the argument that the cellular structure and computational properties of the mammalian hippocampus might resemble those of the octopus memory system.)

Functionally, however, it is possible to find similarities between cephalopod brains and vertebrate brains, even if it is difficult to do so anatomically. Mather discusses the evidence for lateralized specialization of function in the cephalopod brain at length (that is, the general feature of the brain that two mirror-image halves can work somewhat independently, and may have different functions.) Lateralization is seen in humans and other primates, and seems to be one evolutionary result of the need for cortical tissue to be both locally differentiated and highly interconnected; it allows for more specialized cortical areas, because the right and left sides of the brain need not be functionally equivalent. Thus, the apparent laterality of the octopus brain (as this is already getting on in length, I’ll let you check out Mather’s article for a more complete discussion) might suggest that it has also evolved the sort of complex cognitive capacities that lateralization is associated with in mammals.

Finally, EEG-like recordings have been done in both octopus and cuttlefish, leading to the general (but very preliminary) finding that cephalopods have complex, low-frequency “background” electrical activity in some parts of their brains that seems to vary with their states of consciousness. In addition, they show sensory-evoked changes in this activity, in the same way that human EEGs do. This suggests that some of the gross functional properties of the cephalopod brain might resemble those of mammals on a system-wide level.

All of the arguments by analogy should be taken with a grain of salt, because while it is interesting to consider the possible theoretical importance of the apparent similarities between octopus and vertebrate brains, it seems premature at this point, given how little we know about them. While laterality, distributed low-amplitude electrical activity, and a certain kind of memory system architecture are found in the brains of animals who are almost definitely conscious (eg. mammals and birds,) it’s hard to say that their presence in such highly divergent nervous systems (eg. those of vertebrates and cephalopods) has the same set of functional consequences in all cases.

So there it is – these are the arguments for consciousness in cephalopods. It’s an astoundingly complicated and difficult question, and one that I’m sure I haven’t done justice to. Look for the last planned article of the series later this week, where I’ll reflect upon these arguments and figure out where I stand (and also hopefully invite discussion) on the science of cephalopod consciousness.

Thanks for reading!

P.S. Today is my first day of classes for the Fall semester. Wish me luck!

MATHER, J. (2008). Cephalopod consciousness: Behavioural evidence Consciousness and Cognition, 17 (1), 37-48 DOI: 10.1016/j.concog.2006.11.006

Edelman, D., & Seth, A. (2009). Animal consciousness: a synthetic approach Trends in Neurosciences, 32 (9), 476-484 DOI: 10.1016/j.tins.2009.05.008

Young, J. (1991). Computation in the Learning System of Cephalopods Biological Bulletin, 180 (2) DOI: 10.2307/1542389

Finn, J., Tregenza, T., & Norman, M. (2009). Defensive tool use in a coconut-carrying octopus Current Biology, 19 (23) DOI: 10.1016/j.cub.2009.10.052

In this second post of the series “Cephalopod Consciousness”, I’ll talk about the methods that scientists have used to attempt to study consciousness in animals. For perhaps the first time in the history of this blog, I’ll write about science without making any specific reference to cephalopods – I’m saving that for part 3. Here I’ll just cover enough background get a basic handle on the study of consciousness in non-humans, so that I can talk all about its application to cephalopods next time.

I’ll refer primarily to three review articles as I move through the various paradigms used to argue for or against non-human consciousness. These articles are Animal consciousness: a synthetic approach by Edelman and Seth (2009), Subjective experience is probably not limited to humans: The evidence from neurobiology and behavior by Baars (2005), and Affective consciousness: Core emotional feelings in animals and humans by Panksepp (2005). There are many good articles and books on the topic that I am not covering here, so feel free to point out what might be better/useful sources in the comments if you think I’ve missed something important.

In any case, let’s dive right in!

We have to start out assuming that the question of consciousness in non-human animals is worth investigating (eg. that my last post in the series contained at least one valid argument – I might be pushing my luck, but bear with me!) Where do we start?

The first thing to do is to operationalize consciousness. We have to determine how we will identify consciousness in non-human animals, if it exists. The classic way of studying consciousness in humans is through “accurate report”, which Edelman and Seth (2009) define as “a first-person account of what an individual is experiencing, made without the attempt to mislead.” Assuming that you believe that other humans are actually conscious (which can be argued; I won’t get into that here, though,) this is as direct a way as any to study consciousness. It is, however, very difficult to do with animals, as we for the most part lack any reliable form of verbal communication with non-humans. Notable possible exceptions to this include parrots (like Alex the Grey Parrot, who learned language well enough to pretty unambiguously demonstrate cognitive capacities such as numerical representation and the ability to categorize objects) and some chimpanzees who have been taught to use simple language (for example, Washoe, who was taught to use American Sign Language to communicate with her keepers.) Despite these exceptions, linguistic reports remain a rare and difficult-to-use tool for studying consciousness in animals.

One way of working around the inability of most animals to use language (and our inability to interpret the other ways they might be projecting information) is to allow the animals to report on their experience through some sort of trained response, such as by pressing a lever, pushing a button, or another physical activity. For example, Baars (2005) describes a study (Cowey and Stoerig, 1995) in which Macaques were trained to touch a screen where a target stimulus appeared, and then also to indicate (by pressing a button) whether they had perceived any stimulus on the screen (known as a “signal-detection task”, this is a pretty standard way to determine whether an intact animal can sense something.) After damaging parts of the cortex that process visual information in these monkeys, the experimenters found that they continued to point to the correct spot, but they not longer reported seeing a stimulus when the stimulus was in a certain part of the visual field. This parallels a phenomenon known as “blindsight” in humans, where a subject will claim not to perceive anything in a part of the visual field but will otherwise show basically normal behavioral responses to objects in that portion of the visual field. By training the monkeys in this study to report on their experience, the authors of this study were able to show that their awareness of their sensory world is separable from the at least some of the basic functionality of their sensory world, arguing that they have some sort of conscious perception of the world on top of the ability to make motor responses to sensory stimuli. By providing a way for animals to make “commentary” on their experience, Baars claims, methods like this provide a method of studying consciousness that is functionally equivalent to the method of accurate report in humans.

In some cases, animals do not need to be trained to show behavioral evidence of complex cognitive processes, which suggest (but importantly do not prove) the existence of consciousness. For example, as part of their arguments for the possibility of consciousness in birds, Edelman and Seth (2009) cite observations of birds exhibiting object constancy (which is the ability to attend to an object even though it leaves the visual field, such as when it is hidden behind another object – for example, peek-a-boo is fun because young babies do not have object constancy, and so they act as if you disappear when you are hidden from sight,) using and modifying tools, and changing their behavior based on their perceptions of being watched by other birds. They argue that these behaviors show that birds have a working memory and spatial cognition as well as “the ability to make sophisticated discriminations and to plan behaviors before executing them.”

Other behavioral experiments get at the question of whether animals have “selfhood” – that is, do animals have a sense of identity? Such a distinction between self and other is considered key to the sort of “higher-order” consciousness that humans have. The most classical method of doing this in humans and apes is by testing to see if they can recognize themselves in a mirror. This ability is rather straightforwardly called Mirror Self-Recognition (or MSR.) It has been used on many animals, and some that appear to have the ability to recognize themselves include dolphins, chimpanzees, gorillas, and (in one of my new personal favorite behavioral studies by Plotnik et al., 2006) elephants.

If you’re like me, you’re a bit troubled right now. These behavioral methods fall short of actually addressing consciousness per se, and they would never fly as an argument for consciousness in animals in and of themselves (actually, the results with macaques are a veritable one-hit KO in this argument, but only because they involve a species so closely related to humans – arguments from analogy to more distant evolutionary relatives require correspondingly more evidence to make.) Behavioral experiments do not solve the problem of identifying the internal states of animals, which is what we mean when we say “consciousness.” In a particularly lucid explanation of how this problem might be solved despite the shortcomings of behavioral evidence to inform us about internal states, Panksepp (2005) argues for a “psycho-neuro-ethological triangulation” strategy to address the problem of animal consciousness. According to this strategy, we should use neurological processes (some well-studied ones are the mobilization or production of neuroactive chemicals in the body and changes in EEG patterns) as a link between the behaviors we know to be associated with conscious states in humans (in his argument, emotional states in particular) and analogous behaviors in animals. For example, we know that humans feel pain when they are burned by a hot stove (the “psycho-” component of the strategy), and they then withdrawal from the stove and attend to the site of injury. If we watch a rat touch its paw to a hot piece of metal and get burned, we can observe the same sort of reaction (the “ethological” component of the strategy.) Finally, we can attempt to identify neural processes in the rat that correspond with this behavioral reaction in the rat and in humans, as well as neural processes that correspond specifically with the perception of the event (in this case, pain) in humans. If we find that homologous neural processes and behaviors occur in both cases, we have a good case for suggesting that analogous subjective experiences also occur.

In apparent agreement with this idea, both Baars (2005) and Edelman and Seth (2009) make a case for the identification of consciousness in non-humans through the study of neural processes that resemble those associated with human consciousness. The latter authors, in their argument for the possibility of consciousness in birds, identify the presence of human-like (or conscious-like) EEG patterns in birds and the presence of a neural circuit analogous to the thalamocortical circuit of humans (which has been shown through studies of brain-damaged patients and neuroimaging studies to be closely associated with consciousness) as evidence supporting the interpretation of bird behavior as indicative of consciousness. Baars argues that the apparent evolution of these brain structures suggests that consciousness is universal at least among all mammals. Because conscious states and phenomena (for example, wakefulness, REM sleep, and sensory perceptions) are modulated by brainstem structures and “seated in” the thalamocortical circuit, structures which have not undergone much overall structure change throughout mammalian evolution, they are likely to be conserved across all mammals. This is what he claims – I regrettably do not have the expertise in paleobiology or comparative anatomy to agree with or dispute his claims about brain evolution, but they sound like they could be disputed.

In essence, the argument for consciousness in animals remains an argument by analogy from the easily acceptable existence of consciousness in humans. It uses both behavioral and neural evidence to build this case. Critically, though, it makes use of comparative neuroscience to support the existence of consciousness in non-human vertebrates. Remember, though, that non-human mammals and birds are relatively closely related to people, and so their neuroanatomy is (arguably) suitably homologous to human neuroanatomy to make such an argument. What can we make of this line of inquiry when we try to apply it to an animal that is, evolutionarily speaking, much more distantly related to humans – say, an octopus?

Tune in next time to find out!

(For those who are interested in the topic, the journal Consciousness and Cognition put out an issue dedicated to animal consciousness in 2005. It’s very worth checking out.)

BAARS, B. (2005). Subjective experience is probably not limited to humans: The evidence from neurobiology and behavior Consciousness and Cognition, 14 (1), 7-21 DOI: 10.1016/j.concog.2004.11.002

Edelman, D., & Seth, A. (2009). Animal consciousness: a synthetic approach Trends in Neurosciences, 32 (9), 476-484 DOI: 10.1016/j.tins.2009.05.008

PANKSEPP, J. (2005). Affective consciousness: Core emotional feelings in animals and humans Consciousness and Cognition, 14 (1), 30-80 DOI: 10.1016/j.concog.2004.10.004

Plotnik JM, de Waal FB, & Reiss D (2006). Self-recognition in an Asian elephant. Proceedings of the National Academy of Sciences of the United States of America, 103 (45), 17053-7 PMID: 17075063

Cowey, A., & Stoerig, P. (1995). Blindsight in monkeys Nature, 373 (6511), 247-249 DOI: 10.1038/373247a0

I periodically (read: every 2-3 days) search Youtube for new videos of cephalopods, and my most recent search turned up three good ones that I want to share.

First is this little guy, whom the video poster says is a cuttlefish. I think it’s a bobtail squid of some sort. They are known to bury themselves and have specialized skin on their dorsal body surface that holds grains of sand on the skin, providing camouflage. This video shows both of these behaviors:

This next one is some stock footage of the flamboyant cuttlefish, Metasepia pfefferi.  If you’ve ever wondered why it’s called “flamboyant”, watch this:

Finally, Terry Lilley (who is apparently a marine biologist who gives eco-tours) narrates this great clip of an octopus (I’d guess O. cyanea) jetting about and changing colors. Who else is wondering about the affective/conscious state of the animal as the videographer chases it about? This is the sort of ethical quandary I was talking about in my last post!

Thanks for reading, and I hope you’ve enjoyed these!

This is part on of my series looking to answer the question: “Are cephalopods conscious?” In this post, I’ll try to pin down just why it matters whether or not cephalopods have consciousness.

Consciousness is a difficult term to define, but (working from the Stanford Encyclopedia of Philosophy page on the subject) it seems to be best captured by the criterion of awareness. A conscious creature is one who is aware of the world, who has some subjective state which allows them to experience things. More strictly, we might say that a conscious creature must be aware of itself – it must have some notion that it exists, and that it is separate from the rest of the world. Obviously, the ability to have complex internal representations of things is generally considered a prerequisite to this sort of consciousness. This is sometimes called “cognitive ability” (perhaps more properly, the abilities to perform various tasks requiring this capacity are called “cognitive abilities”.) It does not necessarily imply consciousness, but consciousness as defined here requires that an animal to be able to form such representations of the world “before” it can be considered conscious.

Some authors use the term “primary consciousness” and “secondary consciousness” to refer to different aspects of what others call “cognition” – that is, an animal with “primary consciousness” has awareness of sensory impressions and emotions, and an animal with “secondary consciousness” can think about its experiences.  Either of these abilities might be spoken of as being part of the workings of cognitive abilities, with or without any implication in consciousness.  The primary/secondary terminology emphasizes that consciousness probably comes in many varieties that cannot always be easily described using the binary concepts of “conscious” and “non-conscious”.  This is especially important to keep in mind when talking about animal consciousness, as it is likely than other species have consciousness that is qualitatively very different from ours, but can still be identified as the same type of phenomenon.

It’s relatively easy to determine if a human is conscious; you just ask them. The fact that we can use language makes it very easy to determine if a human is currently conscious (that is, not in a deep sleep, dead, or in a coma.) In general, though, we’re comfortable making the assertion that humans are conscious. It is much harder to make this case with non-human animals (hereafter just called “animals”.) Because animals generally cannot directly report their experience to us – or because we cannot understand their reports well enough – we have difficulty knowing from an animal’s behavior whether or not it is conscious, or how to characterize its possible consciousness. We can determine the extent of an animal’s cognitive abilities relatively routinely using a variety of tests. This approaches the problem of consciousness tangentially, and from these tests we derive most of our information about the possibility of consciousness in animals. I’ll get more into this in Part 2 of this series of posts. For now, another question is at hand:

Who cares? Why in the world should we be concerned with the mental states of animals? In particular, why do we want to know if cephalopods are conscious?

I’ll answer this question two ways: first, as a scientist, and second, as an ethicist.  There are probably other reasons to care, and I cannot cover either of the ones I have chosen exhaustively.  In any case, let’s press forward:

Scientifically, the question of animal consciousness (mostly studied these days in terms of animal cognition) is exceedingly important to neuroscience, zoology, psychology, and biology-in-general. If we accept the dogma of neuroscience, specifically that the nervous system is responsible for all of the behavioral and mental processes of an animal, then it must be that the brain of an animal is responsible for that animal’s consciousness (humans included.) If neuroscience is supposed to learn how the brain works, then it within the goals of neuroscience to understand how the functioning of the brain gives rise to consciousness. As neuroscience is not just about human nervous systems, but nervous systems in general, it is important that we know whether animals are conscious, and if so how this consciousness might differ from or be similar to our own consciousness.

Besides being a good subject for science fiction movies, “solving” consciousness in terms of neural function would also be a huge theoretical milestone for neuroscience and computer science. It might allow us to construct computers that were conscious, and could perform tasks with human-like (or even animal-like) intelligence. Because consciousness is widely thought of as one of the most complex and integrative brain functions (that is, it involves the action of a very large and very variable group of brain areas and functions,) it is likely that, by the time we reach this goal, we will have solved most of the rest of the functions of the brain as well. Thus, understanding consciousness is an important goal in neuroscience.

In zoology, ethology, and psychology, all of which attempt (at least in part) to understand behavior, the question of animal consciousness is central. If animals use conscious processes to make decisions, then it is appropriate (and indeed, necessary) that we identify these and study the animal’s behaviors on these terms. As it stands, cognitive processes are recognized throughout a wide swath of the animal kingdom, but we have yet to reliably extend our inquiry to consciousness. Thus, understanding if and how animals are conscious is important to understanding animals and their behavior in general, which is the goal of these disciplines.

Why cephalopods, though? As I’ve harped on before (for example, here, here, here, and here,) cephalopods are a unique group of model animals in the comparative study of the brain and behavior. Most of the anatomy (and presumably the function) of their nervous systems evolved independently from the other animals we usually grant “cognitive” or “conscious” status to (eg. birds, mammals, and possibly reptiles.) When we theorize about the relationship between neural function and cognition, we can use cephalopods as a way to test our theories about what sorts of neural circuits and/or patterns of activity correspond with different cognitive faculties and conscious states. This is only true if, in fact, cephalopods can be conscious. As far as cephalopods are generally useful in developing theories of behavior and brain function in general, they are useful in the scientific study of consciousness – that is, if they are conscious. Thus, determining whether cephalopods are or are not conscious is important to the future of the comparative study of behavior and cognition.

Finally, the question of cephalopod consciousness has implications for how humans should use animals – that is, in terms of the ethics regarding the way that humans interact with other animals. Panksepp (2005) lists 5 reasons for studying affective consciousness (while he’s interested in emotions, many of the same arguments apply to consciousness in general,) including the following: “an understanding of affect in the lives of other animals may be critical for making informed choices on how we ethically treat other creatures… By failing to study such issues, we may continue to deny animals the respect they deserve.”

If we are going to have a rational ethics that can instruct us as to what is permissible and what is not permissible to do with animals (a goal that all of us should have,) we need to know if animals experience the world, and if they do, how they experience it. The ethical stance most commonly taken when looking at the use of animals by humans, welfarism, has at its center the idea that the suffering and discomfort of animals should be considered when using animals; specifically, the suffering of any animals that people use should be minimized. The focus is on the “welfare” of the animal, which means its general well-being, comfort, and quality of life. This is different from the case for “animal rights”, which ascribes to animals rights not to be treated as a means-to-an-end that, like the rights we ascribe to people, would prevent them from being ethically used by humans at all. As (for example) researchers, farmers, and the pet industry are still using animals, and they (and by proxy, all of us who make use of their discoveries and products) depend on the continued use of animals, we mostly reject the latter argument, focusing on the welfare of animals instead of the rights of animals. It’s a somewhat subtle distinction, but it’s important. From a welfare-based perspective, which is based on preventing suffering, it is important to know how animals can suffer. It seems likely that having self-awareness can allow an animal to suffer in more and possibly deeper ways – for example, from loneliness, self-pity, shame, boredom, unfulfillment, anger, and so forth. Thus, the question of animal consciousness is important to animal welfare-based ethics. From a rights-based perspective, the consciousness of animals is not as important. The supposed right of animals not to be used by humans is intrinsic to sentient animals (that is, animals who can sense and react to their environment.) From this viewpoint, regardless of their specific capacity for cognition or conscious awareness, these animals should be protected from human use. I’ll just (for convenience, because it’s what I believe, and because it’s the dominant view, socially speaking) adopt a welfarist perspective on the ethics of the use of animals.

How does this apply to cephalopods? Well, humans use a lot of cephalopods. More than 4 million tonnes of cephalopods were harvested from the oceans in 2007, according to the FAO yearbook of Fishery and Aquaculture Statistics for that year. Perhaps particularly troubling, depending on the capacity of cephalopods to suffer, is the practice of eating extremely fresh cephalopods – that is, those who are still alive (or killed/incapacitated just prior to eating,) which, as a quick YouTube search will attest, is not unheard of in southern Asia and maybe elsewhere. In addition to their use as food, smaller numbers of cephalopods are kept as pets, as research animals, and in aquaria. If the study of the possibility of consciousness in cephalopods is necessary to inform our ethics regarding how we treat cephalopods (and it seems like it is, given how important consciousness appears to be to our common-sense notions of “suffering”, and even some philosophical formulations thereof) then we should get on the ball and pursue this research.  That is, if we accept the welfarist position, and we want to have a scientifically reasonable ethical viewpoint, both of which I think are relatively conservative assumptions.

I should note, before I finish this up, that the science of animal consciousness and the ethical question of animal consciousness relate to each other, but make different assumptions. Scientists are necessarily conservative about making positive assertions, and for good reason – it’s bad science to speak as if a thing (like consciousness in non-human animals) exists if there’s not some positive evidence for it. Put another way, scientific theorizing is set up to rigorously avoid false positives. On the other hand, in a system of ethics that is based on preventing suffering, it’s more important to avoid false negatives than to avoid false positives. In making an ethical decision about a certain animal (or person,) one would rather accidentally treat an agent that doesn’t need ethical considerations as if it does than to unwittingly subject that agent to undue suffering by assuming that it doesn’t have the capacity to suffer in a certain way. Thus, welfare ethics demands that we fastidiously avoid false negatives in the case of consciousness and other psychological phenomena that might determine an animal’s capacity to suffer, even at the expense of occasional false positives.  Essentially, given no other information than our impression that animals might have consciousness, a scientist should assume that they don’t, and an ethicist should assume that they do.  The best solution to me seems to be to entertain both ideas, and apply them to different problems as the specific problems demand it.

I suspect that this mention of the ethics of using cephalopods will garner more attention than the discussion of the scientific value of the study of consciousness in cephalopods, if only because animal ethics is more politicized than the comparative psychology, and is perceived as somewhat easier to talk and theorize about without much technical background.  I don’t want it to seem as if I’m making an argument for or against any use of cephalopods at this point – although I think this is an important issue, I’m not trying to deal with it here.  I’ve tried to keep this post free of any ulterior agenda, and I think I’ve largely succeeded.  The next few posts will be more science-y and less philosophy-y, I promise – although it’s sort of hard when talking about consciousness, which is written about by philosophers far more often than by scientists.

Thanks for reading!

PANKSEPP, J. (2005). Affective consciousness: Core emotional feelings in animals and humans Consciousness and Cognition, 14 (1), 30-80 DOI: 10.1016/j.concog.2004.10.004

FAO Fisheries and Aquaculture Department, . (2009). Fao yearbook: fishery and aquaculture statistics 2007 (Online Version)

In my last few in-depth posts before the school year begins (during which I’ll have considerably less time to spend writing in-depth posts here,) I want to tackle a topic that’s been exciting me and bothering me for a while now: the possibility of consciousness in cephalopods. This is a difficult topic to cover for many reasons, notably that it’s difficult to get anybody to agree on a good functional definition of “consciousness”. In any case, I’m going to take 4 posts to deal with this issue. I’m laying out my plans ahead of time to keep myself on track, as well as to build up some entertaining suspense for you, dear reader. Here’s my plan:

Part 1: Who cares?
In the first post, I’ll discuss why we want to resolve the question of cephalopod consciousness. I’ll briefly define the problem and some relevant terms, and then I’ll look into the ethical and scientific problems that the confirmation that cephalopods have consciousness might raise or settle.

Part 2: The Case for Animal Consciousness
To make sure that we have plenty of background on the topic before I discuss cephalopod consciousness, I’ll review important points of the study of consciousness in general. I’ll more extensively define what we mean by “consciousness” in animals, and how we might go about figuring out if it exists and what its properties are.

Part 3: The Case for Cephalopod Consciousness
In the third post in the series, I’ll discuss how the approaches reviewed in Part 2 have been used to address the question of cephalopod consciousness. I’ll try to look briefly at the history of the study of consciousness (and related constructs like “intelligence” and “cognition”) in cephalopods, and review as much of the relevant scientific literature as is possible without making the post too technical. This will be the meat and potatoes of the series, so to speak.

Part 4: Reflections
In this post, I’ll goof off, editorialize, and promote ridiculous armchair hypotheses about cephalopods, consciousness, and all sorts of tangentially related topics. Or maybe I’ll just recap the arguments review in the other posts and offer a brief summary of whatever side I end up taking, and why I took it. I haven’t quite decided which way to go with this yet.

You can be pretty sure that my coverage of the question of cephalopod consciousness won’t be biased by my prior knowledge on the topic – I have almost none! Let the next 1.5 weeks be a journey of discovery for both of us! (Speaking of which, if anybody has any good resources on the subject that you think I might otherwise miss, please leave them in the comments. I need all the help I can get, trust me.)

Thanks for reading!

I was tagged by Jason at The Thoughtful Animal to partake in a meme. This meme stipulates that I:

1. Sum up [my] blogging motivation, philosophy and experience in exactly 10 words.

2. Tag 10 other blogs to perpetuate the meme.

My answers:

1. Saw the octopus at Pittsburgh Zoo. Cephalopod blog, why not?

2. I’ll tag everybody else on the SFS Network, for starters, and then a few more. That means:
Andrew, David, and Amy at Southern Fried Science
Chuck at Ya Like Dags
John at Mammoth Tales
Will at Bomai Cruz
Mike at Arthropoda
Dustin at Spawning is Immanent
Arvind at Fins to Feet
Anna at Anna’s Bones
and Christopher Taylor at Catalogue of Organisms

Almost 40 years ago, a video called “The Squid and its Giant Nerve Fiber” was filmed, showing (among others) J. Z. Young and A. L. Hodgkin preparing a squid giant axon for electrophysiological study and demonstrating some experimental techniques. I’ve embedded one clip, but be sure to check out more clips at this course website from Smith College (thanks to whoever teaches Bio 300 there for putting these up, by the way.)

As far as Worldcat knows, this videocassette is only housed in one library in the world – in Massachusetts. If anybody is hanging around Hampshire College and wants to make me a copy of this video, I’d be greatly appreciative.

Let’s take a minute to talk about connectomics.  No, not genomics.  No, not metabolomics.  Not any of the other -omics, but connectomics.  It’s a new-ish field that the computational neuroscience geek in all of us can love.

By way of introduction, the “connectome” is the “network of elements and connections forming the human brain” (according to Sporns et al, 2005).  Let’s forget the part about human brain, and (for the purposes of this post) say that a connectome is the set of all the neural connections in a nervous system.  Connectomics is the subfield of neuroscience that attempts to understand the structure and function of nervous systems by studying these connections as a whole.  The goal of this discipline is to determine the anatomy of the nervous system to a very fine scale (on the order of individual cells), and then relate this structural information to the functioning of the nervous system.  “Solving” a connectome is achieved when the connections between all the neurons in a nervous system are mapped.  This has been done for C. Elegans, a nematode who has only 302 neurons, by the use of electron microscopy – this work is summarized in White et al., 1986.  Since then, we’ve expanded our goals, with the Human Connectome Project aiming to solve the connectome of the human brain.   Let’s step back for a second, though, and ask: why do we want to know all of this?

Since the elucidation of the electrical properties of neurons (which, by the way, started with the squid giant axon – you can read one of my older posts about that topic here ), neuroscientists have been interested in the information that neurons carry.  A nervous system can be thought of as an organ that processes information to tell the rest of the body what to do.  Some stimulus might impinge upon a sensory organ (let’s say, for example, that one sees a car speeding towards one’s self,) which causes a cascade of electrical activity through the nervous system, eventually leading to such diverse effects as the movement of one’s muscles to carry one’s self out of the path of the car, the emotional distress that occurs when one is almost killed by some jerk who isn’t paying attention to the road, and the realization that one has just gotten very lucky.  Later on, one might tell the story of this near miss to her friends over dinner, exhibiting the ability of the nervous system not only to process, but to store information for later use.  Further demonstrating this ability, one might learn not to walk in the middle of the road in the future.  The ability of animals to exhibit behavior, to move, feel, and learn, is all due (according to the dogma of neuroscience) to the processing of information by cells in the nervous system.

Now, it’s relatively routine to study how a single neuron processes information.  To sum it up very briefly, information enters a “typical” neuron in the form of electrical impulses on that neuron’s dendrites.  The information flows through the neuron (as an easy-to-get analogy, imagine electronic information flowing through the wire) and then a decision is made: at any given time, if a neuron is electrically excited enough, it can discharge an action potential.  An action potential is a burst of electrical activity that will travel through the neuron’s axon to affect the activity of other neurons that the axon makes synapses with.  Thus, one can imagine a general flow of information through a neuron from the dendrites, through the cell body, and out the axon.  A nerve cell is diagrammed below, with the dendrites and axon clearly labeled, showing the flow of electrical impulses through the neuron.  Such neurons are linked together to form functional circuits that accomplish complex tasks such as recognizing objects, coordinating movement, and recognizing when food tastes good or bad (to name but a few.)

Think of it this way: each neuron works like a tiny computer processor.  At any given time, it’s integrating all of the electrical signals coming to it, and deciding whether or not to fire an action potential.  Nervous systems can process information because they have many such relatively simple processors connected together to process that information.  (Keep in mind that this is a very simplified, and thus necessarily inaccurate description of the nervous system.  It will have to do for now, however, and gets across those aspects of the function of neurons that are most relevant to the problem of the connectome well enough.)  Thus, to understand the function of a nervous system, one only has to understand the functioning of each of its neurons.  This turns out to be incredibly difficult, and at best we only achieve approximations of this goal.  I’ll come back to this later on.

To study how a single neuron processes information is relatively easy, if we’re selective about which neurons we study.  For example, we could record electrical activity from the optic nerve while we expose the eyes of the animal we’re studying to light.  In this way, we would see the way that different visual signals are encoded by neurons in the optic nerve.  In fact, this has been done countless times in studies on the visual system in cats, frogs, ferrets, and many other species.  Using this method of electrical recording, we can determine how neurons are functionally connected to each other, and how they respond to various inputs.  However, to record electrical information from a neuron requires that one physically place an electrode into the brain, and also requires that one focus on a single neuron or a small subset of neurons at a time.  To figure out how an entire brain functions in terms of the interaction of millions of individual neurons would be all but impossible using these electrophysiological methods.  In addition, this method can never be employed on humans, as it is considered unethical to put electrodes into peoples brains without an urgent medical need (of course!)

Another now-classical way of learning about the connections between neurons in a nervous system is through tracer studies.  In these studies, neurons in one part of the brain are dyed in some way.  Then, other parts of the brain (or the whole brain) can be examined to see if they have dye in them.  If they do, it’s concluded that the neurons make some sort of connection between the part of the brain where the dye was injected and the part of the brain where the dye was later seen.  This has many of the same downfalls as electrophysiological methods of figuring out neural circuits.  For one, it can only be done in a small group of neurons in any preparation, and so the connections in the nervous system must be mapped out piecemeal, a few at a time.  In addition, it is often difficult to tell what route an axon might take from the cell body to its destination, even if it is clear where each of these points are.

The difficulty that these methods have in resolving the microscopic structure of the nervous system beg for a faster, more flexible technique.  Even the reconstruction of the relatively simple nervous system of C. elegans, done using images from an electron microscope, had to be done largely by hand.  These processes are labor- and time-intensive, and do not lend themselves well to the reconstruction of nervous systems that may have millions or billions of neurons.

Enter the field of computational neuroscience.  Computational neuroscientists study nervous systems in terms of their information processing capabilities.  Standing at the junction of computer science and neuroscience, they have both the tools and the impetus to understand the details of the connectomes of whichever organisms they study.

An approach that has been taken in humans involves using the technique of diffusion tensor imaging, and MRI technique that can determine the direction that axons run in in an intact brain.  For example, the following image (by Thomas Schultz) shows a DTI-derived image of the connections that run through the midline of a living human brain:

Such images are of great potential use in studying brain lesions, doing studies on brain function, clinical diagnosis, and whole-brain level analysis of neural circuits.  However, they lack the resolution needed to map individual synapses, thus falling short (for the time being) of being able to comprehensively map the connections between neurons in a brain.  For this, we have to go to microscopy techniques that involve looking directly at neural tissue.  These can only been done in animals, because it is presently illegal to harvest brain tissue from humans for experimentals purposes (again, a no-brainer.)

By now, you’re wondering when I’ll mention a cephalopod.  After all, this is a blog about cephalopods.  You have every right to expect that I’ll mention squids, octopodes, or nautiloids at least once in each post.  Never fear!

Last week I came across a poster presentation write-up on Biomed Central called “Charting out the octopus connectome at submicron resolution using the knife-edge scanning microscope.”  As you might imagine, I was tickled.  A research team with members from Texas, Naple, Michigan, Illinois, California, and Seoul (including Graziano Fiorito, notable for his research on observational learning in the octopus) is working on reconstructing the octopus connectome using a mostly-automated 3D microscope called the knife-edge scanning microscope (KESM).  This microscope takes a block of tissue and slices it, taking a picture of each slice of the tissue as it is cut.  Then, a computer program can create a high-resolution 3D image of the tissue.  From this, the computer can (and this is the tricky part) automatically trace the paths that nerve cells take through the tissue, and – this being the goal of this research – reconstruct a detailed network showing the morphology of each neuron in the tissue.  For examples of the resulting images, you can see this gallery from the brain networks laboratory at Texas A&M.

Why the octopus?  Well, in an introduction that makes the comparative neuroanatomist in me jump for joy, the authors suggest that because “the neural architecture of this cephalopod mollusk differs markedly from that of any vertebrate… [investigating] the difference and simlarities between the neural architecture – or connectome – of the octopus and mammals, such as the mouse, may lead to deep insights into the computational principles underlying animal cognition.”  In their concluding remarks, the authors note that they “expect that this pilot study and the more detailed investigations to follow will allow fruitful comparisons of the neural circuitries of individual octopuses with different ecological life histories, as well as of animals that have been exposed to a variety of neurodegenerative insults… In sum, this approach should contribute greatly to our understanding of the computational architecture of invertebrates and ultimately provide insights into the differences between invertebrate and vertebrate cognitive capabilities.”

I’m intriguied by this article, but also a little dissappointed.  Mostly, I’m dissappointed that a more complete study isn’t out yet!  I’ll be watching these guys from now on, and I’ll cover any other publications they put out on the topic.  Hurrah for octopus connectomics!

In closing, I want to mention that a complete neuroanatomical picture of a nervous system does not actually explain its computational properties.  To understand how nervous systems process information, we need to know the physiology of each cell and the biochemistry of the interactions, a topic that is probably more complex than even the very fine-grained study of neuroanatomy represented by the studies I’ve mentioned here.  In terms of our understanding of nervous systems, however, connectomics offers and opportunity to study the relationship between the cellular structure of the nervous system and its overall capabilities – a relationship whose description has been one of the goals of neuroscience practically since its inception.

Thanks for reading!

Sporns, O., Tononi, G., & Kötter, R. (2005). The Human Connectome: A Structural Description of the Human Brain PLoS Computational Biology, 1 (4) DOI: 10.1371/journal.pcbi.0010042

Yoonsuck Choe, Louise C Abbott, Giovanna Ponte, John Keyser, Jaerock Kwon, David Mayerich, Daniel Miller, Donghyeop Han, Anna Maria Grimaldi, Graziano Fiorito, David B Edelman, & Jeffrey L McKinstry (2010). Charting out the octopus connectome at submicron resolution using the knife-edge scanning microscope BMC Neuroscience, 11 (Supplement 1), 136-137 : 10.1186/1471-2202-11-S1-P136

MAYERICH, D., ABBOTT, L., & McCORMICK, B. (2008). Knife-edge scanning microscopy for imaging and reconstruction of three-dimensional anatomical structures of the mouse brain Journal of Microscopy, 231 (1), 134-143 DOI: 10.1111/j.1365-2818.2008.02024.x

White, J., Southgate, E., Thomson, J., & Brenner, S. (1986). The Structure of the Nervous System of the Nematode Caenorhabditis elegans Philosophical Transactions of the Royal Society B: Biological Sciences, 314 (1165), 1-340 DOI: 10.1098/rstb.1986.0056

MORI, S., & ZHANG, J. (2006). Principles of Diffusion Tensor Imaging and Its Applications to Basic Neuroscience Research Neuron, 51 (5), 527-539 DOI: 10.1016/j.neuron.2006.08.012

Not that I like to brag, but… I guess I like to brag some times.

The University at Buffalo News Center put out a press release about Cephalove! I feel so special!

Also, this takes the cake as my shortest blog post ever, I think.  I’ll be back with more by the end of the weekend.

Thanks for reading!

Alistair Merrifield, today’s featured cephalopod photographer, is a biostatician who lives in Sydney. He has great photos of a variety of subjects on his Flickr page.  The images should be click-through-able, so you’ll should go check out the high-resolution versions on Flickr.  All the photos in today’s post are owned by Alistair.

We’ll start out with some cuttlefish.  These next two shots are all of Sepia apama, the Australian giant cuttlefish.  In case you didn’t know, these guys are the largest cuttlefish in the world, and are absolutely beautiful.  They’re a popular tourist attraction of the southern Australia coast, because they’re apparently pretty easy to find and very fun to dive with.

The latter one reminds me for all the world of the painting “American Gothic”.

This next image is of  Sepia mestus, the reaper cuttlefish.  They have a rather restricted range off the Australian coast, and exhibit a large degree of sexual size dimorphism, with the females getting to be much larger than the males.  Still, they do not get very big, especially compared to S. apama.

Moving along, check out these two shots of the striped pyjama squid, Sepioloidea lineolata.  Although called a squid, it is actually a cuttlefish,  being in the order Sepiidae.  It is one of the few known poisonous cephalopods along with such illustrious characters as M. pfefferi, the flamboyant cuttlefish and H. lunulata, the blue-ringed octopus, two other poisonous species.

Finally, we’ll close with a close-up of the eye of a blue-ringed octopus.  You can get a good sense of the scale of this shot by looking at the grains of sand on the animal’s skin in the upper right quadrant of the photo.

Thanks for reading/viewing!