Sloppy Language in Science on Human Uniqueness

Mental and behavioural attributes are notoriously difficult to quantify, whether one is speaking of an individual or population. While there are specific well qualified claims that can be made about intellectual abilities or behavioural adaptability, any sort of general sweeping statement about the ‘uniquely human trait of…’, though rife within popular and scientific literature from psychology or neuroscience, tend to crumble under close scrutiny. Making such an unqualified statement irks me, as I believe it fosters an undue reverence for the human brain (despite our heavy reliance on model organisms for neuroscience research), and is reminiscent of Descartes’ baseless theological labeling of all non-humans as mindless automatons. Of course, I am not suggesting that there are not unique or laudable aspects of our species’ cognitive abilities (for example, our penchant for complex linguistic communication is quite impressive, but in no way is communication or even language a uniquely human endeavour. Human language is a unique and impressive cognitive trait that has helped enable our species to accomplish some truly impressive feats, but nailing down just what exactly makes our language quintessentially human (other than being used by humans) is astonishingly difficult). The difficulty of making cross-species generalizations is further compounded by our inability to break away from our own human perspective. In the same way that we must be careful not to incorrectly attribute cognitive abilities and methods to non-humans through overly zealous anthropomorphism, we must be wary of missing the abilities of other animals through the sheer alien nature of the abilities (for example, while we are now quite comfortable with the idea of bats utilizing echo-location to navigate and hunt, when sonar was a top-secret military technology it was a startling and preposterous revelation).

Given the sloppiness of such ‘uniquely human’ generalizations, therefore, I was quite astonished to see a ScienceNOW article not only referencing Descartes in the first sentence but following it with the question, “What imbues us with this uniquely human sense of self-awareness?” The news brief, written by Greg Miller, is apparently based on a paper in Nature Neuroscience1 (I say apparently because I was unable to find an explicit reference). Reading through the paper itself, I noticed no such sentiments. Rather, the paper served as a brief and informative summary of a study on interoceptive awareness using a comparison test of heartbeat sensation in a brain lesion patient and uninjured control subjects. Greg Miller does a perfectly fine job of summarizing the actual methods and results of the paper in the rest of his news brief, so I will not dwell on those here. I simply take issue with his opening lines.

The definition of self-awareness is itself a matter of some contention, but in the sense that this study comments upon (awareness of changes in visceral function) I find it bizarre that anyone would even contend such a sense was uniquely human. After all, rat behaviour will markedly change following an injection of cortisol2 despite cortisol’s extremely low penetration of the blood-brain barrier3. Interestingly, in Vinogradova and Zhukov’s paper2 the behavioural response to cortisol injections was often of an opposite nature in two different breeding strains that were selected for high or low rates of acquiring active avoidance behaviour. Such differences are at least plausibly suggestive of an ambiguity in the interpretation of visceral changes brought on by the cortisol injection, similar to the famous ambiguity between fearful and lustful physiological arousal demonstrated by Dutton and Aron4. With two populations bred for opposite learning tactics from fearful stimuli, it is reasonable they would also exhibit a change in their likelihood of interpreting a shift in physiological state as anxiety (which is to a large extent the expectation of fear and horror in the near future).

Moving beyond the self awareness of what is going on within one’s own body to more abstract notions of the self, the mirror test is a classic tool for exploring the subject (although I have my own reservations on the efficacy of the mirror test, those can be saved for another time). Just four short days after Greg Miller claimed that only humans were self-aware, another ScienceNOW news brief came out describing the success of pigs at learning to use a mirror to find food, a measure which, in the words of the lead author Donald Broom, gives pigs at least “some degree of self-awareness”. The article also conveniently provides a list of other animals who have passed the mirror test: elephants, dolphins, magpies, gray parrots, and some primates (including humans, which the article for some reason listed separately).

While sweeping statements on human uniqueness are appealing to both our species’ vanity and as a nice opening line to elevate the profundity of the topic at hand, they are misleading and not backed up by evidence. Such language does a disservice to the field of neuroscience and discounts the contribution of model neurological organisms and comparative neuroanatomy to our understanding of the brain and its function.

1 Khalsa, Sahib S., David Rudrauf, Justin S. Feinstein, and Daniel Tranel. 2009. The pathways of interoceptive awareness. Nature Neuroscience, Advanced online publication.

2 Vinogradova, E. P. and D. A. Zhukov. 2008. Changes in anxiety after administration of cortisol to rats selected for the ability to acquire active avoidance. Neuroscience and Behavioral Physiology, 38:781-783.

3 Pardridge, William M. and Lawrence J. Mietus. 1979. Transport of steroid hormones through the rat blood-brain barrier. The Journal of Clinical Investigation, 64:145-154.

4 Dutton, D. G. and Aron, A. P. 1974. Some evidence for heightened sexual attraction under conditions of high anxiety. Journal of Personality and Social Psychology, 30:510-517.

24 Responses to Sloppy Language in Science on Human Uniqueness

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  2. Nigel says:

    “Descartes’ baseless theological labeling of all non-humans as mindless automatons”

    In a post accusing others of sloppy thinking this is rich indeed. Have you actually ever read any Descartes? (And if so, did you understand it?) I am not saying that he was right, but his views on this issue were neither baseless nor based upon theology (by which I presume you mean religious dogma). His conclusions were based upon the latest and best available science of his time (to which he was a hugely important contributor). No doubt many of the “facts” he relied upon are now known to be wrong, but I guarantee you that most of the scientific claims of the past decade will turn out to have been wrong too. Descartes conclusions about human uniqueness may have been consistent with his religious preconceptions, but the case he makes for that uniqueness does not depend upon religion in any essential way.

    “Human language is a unique and impressive cognitive trait that has helped enable our species to accomplish some truly impressive feats, but nailing down just what exactly makes our language quintessentially human (other than being used by humans) is astonishingly difficult).”

    So actually you contradict your main conclusion in your first paragraph. Language is, as you admit, unique to humans, and this is no trivial matter. Language is not just a means of communication, it is a tool of thought that makes human cognition qualitatively different from (and enormously more powerful than) that of any other species we know about. It has made civilization and science possible, and (for good or ill) has given humans an unprecedented degree of control over their environment (note to sloppy thinkers: “control over” does not mean the same thing as “effect upon”). The question of whether (or why) language is “quintessentially human” is a red herring. Almost certainly there is nothing “quintessential” about it. I know of no reason to think that some other species might not one day evolve that has a capacity for language or some other equivalently powerful cognitive/communicative tool. Very likely it has already happened on other planets. What matters, however, is the brute fact that, on this planet, humans are the only species that show any evidence of having such a capacity. (If you can come up with any ape, monkey, dolphin, woodchuck or whatever capable of making an argument – heck, even a sloppy, invalid argument – to the contrary, I will be delighted to change my view.)

    To all intents and purposes, the above was Descartes argument for human uniqueness. Note that it contains no reference to God, the Bible, or anything supernatural. It is true that Descartes did appeal to the supernatural (the immaterial soul) when he tried to explain the human capacity for language (together with a few other yet unexplained phenomena, such as consciousness), but that is an entirely separate issue. The fact that his explanation was unsatisfactory does not imply that his explanandum was misconceived.

    If you are going to accuse others of sloppy thinking, you would do well to avoid filling your posts with half-baked pseudo-scholarship and sloppy rhetorical arguments of your own.

    • caldenwloka says:

      Hi Nigel, thank you for your interesting comment. You bring up some good points.

      “Human language is a unique and impressive cognitive trait that has helped enable our species to accomplish some truly impressive feats, but nailing down just what exactly makes our language quintessentially human (other than being used by humans) is astonishingly difficult).”

      So actually you contradict your main conclusion in your first paragraph. Language is, as you admit, unique to humans, and this is no trivial matter. Language is not just a means of communication, it is a tool of thought that makes human cognition qualitatively different from (and enormously more powerful than) that of any other species we know about. It has made civilization and science possible, and (for good or ill) has given humans an unprecedented degree of control over their environment (note to sloppy thinkers: “control over” does not mean the same thing as “effect upon”). The question of whether (or why) language is “quintessentially human” is a red herring. Almost certainly there is nothing “quintessential” about it. I know of no reason to think that some other species might not one day evolve that has a capacity for language or some other equivalently powerful cognitive/communicative tool. Very likely it has already happened on other planets. What matters, however, is the brute fact that, on this planet, humans are the only species that show any evidence of having such a capacity. (If you can come up with any ape, monkey, dolphin, woodchuck or whatever capable of making an argument – heck, even a sloppy, invalid argument – to the contrary, I will be delighted to change my view.)

      As I said in the previous sentence, “I am not suggesting that there are not unique or laudable aspects of our species’ cognitive abilities”. My conclusion was not that humans are not unique, but that humans are not sweepingly unique. Every species on this planet is unique by the very fact that they are a definable species, but the characteristics providing such a unique differentiation are rarely clear-cut or as broad sweeping as ‘culture’, ‘language’, ‘self-awareness’, or the myriad of other cognitive and behavioural traits commonly trumpeted as uniquely human. The sentence you quote above was differentiating between ‘human language’ and simply ‘language’ (which is why I originally placed emphasis on the word ‘human’), as language itself is not a decisively unique trait of human-kind unless, as I noted, one is defining it by human use (something which is, granted, often done). There are numerous monkey species capable of a number of different vocal utterances with meaning, including the ability to lie and trick each other through alarm calls about non-existent predators and additional modulatory sounds capable of changing the meaning of the phrase. Many of these species are relatively unknown and only beginning to be researched. There are many non-primate forms of communication, as well, and it takes carefully crafted definitions and a lot of study to define and differentiate between the abilities of different communicative forms.

      “Descartes’ baseless theological labeling of all non-humans as mindless automatons”

      In a post accusing others of sloppy thinking this is rich indeed. Have you actually ever read any Descartes? (And if so, did you understand it?) I am not saying that he was right, but his views on this issue were neither baseless nor based upon theology (by which I presume you mean religious dogma). His conclusions were based upon the latest and best available science of his time (to which he was a hugely important contributor). No doubt many of the “facts” he relied upon are now known to be wrong, but I guarantee you that most of the scientific claims of the past decade will turn out to have been wrong too. Descartes conclusions about human uniqueness may have been consistent with his religious preconceptions, but the case he makes for that uniqueness does not depend upon religion in any essential way.

      As an historian of science you are likely much more familiar with Descartes’ work than I am. I recognize that scientific ideas change over time as new understanding and evidence becomes available, which is why I do not take issue with Descartes’ and his contemporaries’ focus on the ventricles. Hypothesizing that our bodies’ movements were created through the movement and pressures of fluids was remarkably clever and fitting with the present day mechanistic understanding. I do take issue, however, with his positing of both a non-physical immaterial soul and the unique possession of that soul solely by humans (despite the clear and distinct presence of pineal glands in other animals). That has always struck me as a stance stemming from Christian doctrine, but if you can suggest specific documents from Descartes’ work where he provides solid and secular reasoning for such a stance, I would certainly be willing to reconsider my statement.

  3. Timothy Underwood says:

    Excellent point, it bothers me too when I hear people thinking A)that we are unique, B) that there is something specially weird about the way which we work.

  4. N Miller says:

    Very nicely articulated discussion, Calden, and a very important insight into science reporting. Words do indeed matter, and keeping language as accurate as possible helps us separate our inferences from our observations.

  5. caldenwloka says:

    I want to apologize to everyone who submitted comments for taking so long to approve them. I have not been paying much attention to my blog over the past little while (as evidenced by the lack of new posts), so it took me a while to get around to giving them a look through and hitting the approve button.

  6. N Miller says:

    We can claim our unique form of language and still occupy just one point among many along the spectrum, mere percentage points away from our fellow Terrans.

    More importantly, I think the point of the post had more to do with the consequences of language use, especially when interpreting scientific results for the benefit of others.

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  12. Joe Duncan says:

    nailing down just what exactly makes our language quintessentially human (other than being used by humans) is astonishingly difficult

    This is not entirely true. There are two related properties of human language that make it very easy to delineate it from other forms of communication.

    This is not to say, however, that other animals might not develop such language later in their evolution of more sophisticated brains, just that none currently have such language now. So I would say that human language is unique to humans at the moment, but the capacity to develop such language is not.

    What distinguishes human language from other forms of communication are that it is both combinatorial and generative. That is we can create new meanings by combining pre-existing elements into new structures and such capacity is infinite. Given all the basic elements of language (words, morphemes etc…) it is not possible to list every single utterance that it is possible to create using the language. We can generate an infinite number of recombinations of the basic elements.

    These properties are not possessed by any form of animal communication that we have yet observed, including sign-language taught to apes. Animal communication can have large vocabularies and sophisticated meanings, but their elements have relatively fixed meanings and are not combined to create new meanings. Whales and birds can come up with new “songs” but again, these are basically fixed, repeating patterns with single meanings (mating songs, basic communications of identity etc…). When we teach sign language to apes, they are limited to very simple grammatical forms like and and they have a finite generative capacity.

    • caldenwloka says:

      Throwing in the phrase ‘astonishingly’ might have been somewhat of an exaggeration, since I was classifying the list of language qualities that you have brought up as not straightforward. That said, I would still argue that there is a continuum to the combinatorial and generative properties you have brought up. For example, studies into monkey alarm calls have displayed a combinatorial capability to derive new meanings to their calls based on combining a pre-existing set of sounds. While this has not been observed to be a large number of combinations (nor am I aware of any grammatical overlay), its existence still necessitates a qualification to the term combinatorial if it is to be used to separate human language from the communicative abilities of Campbell’s monkeys.

      • Joe Duncan says:

        Oh, absolutely. I whole heartedly believe that it is a continuum – I don’t believe there’s anything unique to humans and only humans that gives rise to language.

        However, I do believe that humans are currently so far removed from other creatures along these dimensions as to practically result in a dichotomy.

        Fascinating study BTW, I hadn’t seen it before. Thanks for the link.

  13. Joe Duncan says:

    Huh. Some of my last sentence got filtered out. It should have read:

    When we teach sign language to apes, they are limited to very simple grammatical forms like VERB-NOUN and NOUN-VERB and they have a finite generative capacity.

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