We currently lack strong evidence for consciousness in dolphins suggests Professor Heidi Harley in her recently published review article appearing in the Journal of Comparative Physiology A. For some (perhaps most) cognitive scientists studying animals minds, this is not a particularly controversial conclusion – a borderline truism. For other scientists – and perhaps for nearly everyone involved in issues of animal rights and animal welfare – the suggestion that dolphins are “not conscious” is simply absurd. Lurking between the truism and the absurdity of non-animal-consciousness we find a centuries-old battle over the problem of what consciousness is, and how on earth we’re meant to determine the extent to which non-human animals are conscious. Harley’s review article provides a quick introduction to this minefield of a problem, as well as a review of the current scientific evidence of consciousness in dolphins. If you’d like a quick rundown of this topic but don’t have time to read this article or the 2,500 year’s worth of philosophical musings on the topic of consciousness, I will provide a handy overview of Harley’s main points in the form of a dialogue between Phil, who represents the “of course dolphins are conscious” point of view, and Emily, who represents the “I think you’ll find it’s a bit more complicated than that” point of view. Take it away Phil and Emily:
Phil: It wasn’t that long ago that you skeptical scientist folks refused to entertain the idea that animals could even be conscious. Remember B.F. Skinner or J.B. Watson? It seems to me that scientists have always been closed minded when it comes to animal consciousness – keen to uphold the idea that only humans could even be conscious.
Emily: That might well have been true a hundred years ago, but when scientists like Donald Griffin started writing about the value of studying animal minds, a whole new field of scientific inquiry popped up, and now there are thousands upon thousands of scientists studying aspects of consciousnesses in animals.
Phil: But why is this still even a question? Isn’t it obvious that every animal needs to create a representation of the world in its mind in order to navigate its environment, find food, mate, etc? Isn’t this what consciousness is?
Emily: Not really. That’s just the way brains process and perceive incoming sensory stimuli. It’s not much different to how a solar panel with a light-sensor is able to follow the direction of the sun. Just because solar trackers can perceive light doesn’t mean that solar panels are conscious, does it? No, the kind of complex consciousness that we know humans experience is called phenomenological consciousness – it’s the subjective experience of those stimuli/perceptions. If a solar panel experienced the light in some way, then it might well be conscious. Of course even if it did, it wouldn’t be able to tell us about it, which is why it’s so hard to investigate consciousness in non-linguistic animals (or solar panels).
Phil: So you’re saying that it’s impossible to study consciousness empirically then? Isn’t that what Nagel said? Are you suggesting that because consciousness is completely private, it’s not possible to study at all? If that’s the case, then what grounds do you have for suggesting that dolphins aren’t conscious?
Emily: I think even Nagel suggested that it’s possible to study aspects of consciousness (even though it is private). It might be hard to study consciousness, but it’s not impossible. The field of cognitive science has in fact been quite busy studying the way brains perceive and process information in ways that result in subjective experience. Have you heard of people with phantom limb syndrome? They might be missing, for example, an arm – but their mind still creates the conscious experience of the arm. Weird cases like this allow scientists to determine exactly how different parts of the brain and the body must be interacting in order to create subjective (conscious) experience.
Phil: But you’re missing an important point. Animals do more than just process stimuli to determine if they have an arm or not, or to track the direction of the sun. Plants can follow the direction of a light source, and maybe even sense when they are missing a leaf or something, and I am not suggesting that this means plants are conscious. I am talking about consciousness in animals like dolphins, that produce complex behaviors, including solving problems, tool use, etc. Surely the ability to think about and thus subjectively experience all of these incoming stimuli is required by any animal in order to produce complex behavior?
Emily: It might seem so, but there is plenty of evidence to suggest that brains can produce rather complex behavior without consciousness. Studies in humans show that we perform so much of our complex behavior unconsciously – from driving a car to investing our savings. There’s every reason to believe that most – if not all – non-human animal behavior we see could be being produced by an otherwise intelligent mind that is not producing subjective experiences of its own decision making processes.
Phil: This seems ludicrous to me. Are you saying that if I see a chimpanzee and a human both solve the same experimental problem (e.g., how to build a tool to reach a banana in a tree), that the human accomplished this via consciousness and the chimpanzee did this without consciousness? Why posit two different explanations for the same behavior? Isn’t that an unscientific approach?
Emily: This gets into the problem of how and when it’s appropriate to apply the argument-by-analogy approach to interpreting animal behavior. Just because an animal behaves like a human, does this mean we should assume its mind functions in the same way? Depending on how one decides to apply Occam’s Razor or Morgan’s Canon, it is possible to suggest that the same behavioral outcome was produced by different underlying cognitive processes, and that we should always assume that the simplest explanation is the likeliest one. So in this case, banana-reaching via unconscious thought for the chimpanzee. Again, a computer might also be able to solve this problem, but we don’t suggest that computers are conscious. One of the main problems we’re dealing with here is that science does not really have a good definition of consciousness. Yes, it’s some form of subjective experience, but it might come in a variety of forms, and thus animals might be conscious in different ways to humans. It’s important to point out that human minds are not better than the minds of other animals – all minds are different, and there is no scale that suggests human minds are somehow the best minds due to our form of consciousness or some other cognitive trait. In any event, it’s really hard to know the extent to which the chimpanzee in this scenario solved the problem via conscious thought as opposed to complex but otherwise unconscious thought. The big question is, how can we test for the presence of subjective experience?
Phil: So we’re back to this problem again. So in what ways have scientists been testing for consciousness in dolphins, and why exactly have you reached the conclusion that “we currently lack strong evidence for consciousness in dolphins?”
Emily: Scientists have given dolphins the mirror self recognition (MSR) test. Having some kind of awareness of oneself – whether it’s awareness of one’s body or of one’s own mind – is certainly linked to the idea of consciousness. For these tests, dolphins were marked with a kind of dye on their bodies, and if they then swam over to inspect the mark in a mirror, we could conclude that the dolphins must know that it’s themselves they are seeing in the mirror. This then is some kind of self awareness.
Phil: So did dolphins pass the test?
Emily: For the most part, yes. Although not everyone is convinced that they did. Dolphins, unlike chimpanzees or other great apes (which also pass the test) don’t have hands, so it’s hard to know for sure that they were truly inspecting the marks on their bodies. Chimpanzees can reach up and touch the mark, which makes it obvious what they are doing.
Phil: So if they passed the MSR test, then dolphins are self-aware, no? And if they are self-aware, they must have some sort of subjective experience of themselves, which means they are conscious, right?
Emily: Well, the problem is that being able to recognize one’s body in the mirror (that is, recognizing an external representation of one’s body) might not be the same thing as having a representation of one’s own mind (i.e., a sense of self). So passing the MSR test might not even be a sure test of self-awareness, let alone subjective experience.
Phil: Well what about those studies of metacognition in dolphins and other animals. Isn’t metacognion the same thing as consciousness?
Emily: Dolphins have indeed been tested for metacognition. In these experiments dolphins were able to “report” that they were uncertain as to whether or not a tone they were hearing was a low or a high tone, which meant that they must have known something about their own knowledge. But depending on how one interprets these results, they don’t necessarily suggest full blown subjective experience of that knowledge.
Phil: So hold on a second – are you saying that this is down to a matter of interpretation? That there are scientists who suggest that these and other studies are evidence of consciousness in dolphins?
Emily: Yes, that is indeed the case. Some dolphin scientists, like Lou Herman, suggest that these studies, as well as his studies of dolphins’ abilities to imitate their past behavior, indicate that the most likely interpretation is that dolphins have some kind of higher-order thinking going on that might be similar to consciousness.
Phil: So why are you saying that the evidence is lacking?
Emily: I think that most cognitive scientists take this evidence to mean that it’s certainly possible that dolphins are conscious in a similar way to humans, but that the results of research at this stage have yet to provide us with the smoking gun suggesting dolphin consciousness. In the coming years, we’re likely to see new experiments that are better designed to ferret out the presence of consciousness in dolphins and other animals. But at this stage, there’s just not enough evidence to draw strong conclusions.
Phil: So it’s somewhat a matter of interpretation?
Emily: Yes, I’d say so. Scientist still have a poor understanding of how to define or test for consciousness in animals, so there’s a lot of wiggle room when it comes to interpreting these results. But it’s important to emphasize that the current scientific evidence is simply not strong enough at present to make final conclusions.
Phil: You’re leaving the door open for the possibility of consciousness in dolphins then?
Emily: Of course! Scientists always leave the door open, and I’d love to be the one to design an experiment that solves the problem of how to test for subjective experience in dolphins.
Harley HE (2013). Consciousness in dolphins? A review of recent evidence. Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology PMID: 23649907