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Present imperfect: Is the human brain ill adapted for language?


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human brain language evolve kluge marcusThe spy shot the cop with the revolver.

This sentence, a favorite of linguists, appears to be simple enough. It’s grammatically correct, has a subject and a predicate and can even be easily understood by young children. Or can it? Who had the revolver: the spy or the cop?

Like optical illusions, language can play tricks on the brain, explained New York University psychologist Gary Marcus at an April 6 lecture at the American Museum of Natural History in New York. These simple syntactic ambiguities, he argued, throw a wrench into prevalent theories that the human brain is well evolved—or even optimally evolved—for language.

As evidence for our species’s general optimality, many people point to the complex human visual system, which has yet to be matched by technological developments. So if our brain’s handling of vision is so well tuned, shouldn’t our language centers be, as well?

No way, according to Marcus. Visual abilities have been developing in animal predecessors for hundreds of millions of years. Language, on the other hand, has had only a few hundred thousand years to eke out a place in our primate brain, he noted. What our species has come up with is a "kluge," Marcus said, a term he borrows from engineering that means a solution that is "clumsy and inelegant, but it gets the job done." (His 2008 book, Kluge: The Haphazard Construction of the Human Mind, explores the language subject and other human mental inefficiencies.)

Unlike a computer, which can work with C++ and other languages that lack the ambiguities of say, English or Chinese, the human brain’s capacity to understand language is tied up in how our memory works—and that is deeply rooted in evolutionary pressures, stuck in what he called "evolutionary inertia."

The human brain has a very context-driven memory (unlike computers which have location-based memory), which is why people often have trouble remembering where their car is in a parking lot or parking garage they use frequently, Marcus explained. These mental contextual cues, however, are not ideal for an organized, rational development—or use—of language.

In fact, one sociologist tried to make just such a logical language. The language, called Loglan, was described by its creator James Cook Brown in a 1960 article [pdf] in Scientific American. Unfortunately for Brown, who used mathematic and logic models to build the language, the experiment failed in that people actually had a very difficult time learning the artificial tongue.

But this failure boosts Marcus’s idea that natural human languages are not a product of the well-orchestrated rationality and neat syntactic trees like Noam Chomsky and other linguists have described.

Rather they are messy approximations that manage to get people’s point across. Most of the the time.

Read a conversation with Marcus about his book and research.

Image courtesy of iStockphoto/megatronservizi

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  1. 1. jtdwyer 6:41 pm 04/7/2010

    Since humane language is entirely a construction of the human intellect, the question is invalid.

    The problem of inconsistent rules and interpretations originates from efforts to create a standardized language by a collective process, simply combining the many dialects and variations that develop in lieu of definitive commonly accepted rules.

    C++, for example, is standardized only by a formal process specifically intended to do so. Allowing the dynamic extensibility of any language produces incompatible variations.

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  2. 2. ultimobo 8:23 pm 04/7/2010

    I’ve recently noted that many strangers (in shops and passing contacts) initiate communications with forms of grunts, not easily understood as words.

    My take is that the amygdala/threat assessment mechanism takes highest priority in any new situation, and a brain suffused with the fight or flight hormone has difficulty expressing friendly communications until the initial threat level has subsided.

    My disappointment is that short forms of ego-centric communication (sms, email, facebook) have crippled people’s learning about how to communicate face-to-face, with a tendency to rage with any frustration, to the extent that we have the recent case of a 15-yo racing to ‘kill’ a girl he’d never met, based on his interpretation of a short text message.

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  3. 3. Cybe r. Wizard 8:34 am 04/8/2010

    My own favorite ambiguous sentence is, "she turned on the barbeque spit."

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  4. 4. lowndesw 8:53 am 04/8/2010

    I don’t see the ambiguity in this example as a result of any "brain" shortcomings, rather just an incomplete statement. It is an artifact of our language, specifically English. Other languages have their own ambiguities, resulting from structure to vocabularies.

    Most very brief statements leave out clarifications. Mr. Marcus’ assertion is like taking a picture of the top two feet of the Eiffel Tower and proclaiming "It ain’t so grand.", then blaming it on the camera.

    The example points out that the human mind CAN detect the ambiguity in this written statement, and further that the same statement made verbally might NOT have ambiguity because of intonation, pauses, etc. Such is the difference between the written and spoken word, AND the mind’s ability to compose, decipher, and critique each.

    As for Marcus’ claim that the mind is not "optimally evolved" for language, almost NOTHING living is optimally evolved: the airfoil of a bird’s wing is no where near as efficient as we can make one; walking is no where near as efficient as riding a bicycle.

    I suspect that Marcus’ argument had the desired result: attention to himself.

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  5. 5. jtdwyer 9:43 am 04/8/2010

    lowndesw – Right. The shortcoming is not with our brains, its with our languages. Ambiguity is the price we pay for the dynamic extensibility of our languages.

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  6. 6. lowndesw 11:36 am 04/8/2010

    Thanks, jtdwyer!! You said it all in two short sentences. Perfect!

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  7. 7. jtdwyer 12:30 pm 04/8/2010

    lowndesw – Thank you! However, a real scientist could sell volumes on the subject…

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  8. 8. Doctorant 2:18 pm 04/8/2010

    Would anyone care to comment on the relevance of this to the Chomskyan notion of the deep structure of language?

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  9. 9. aniko 2:40 pm 04/8/2010

    http://www.cassiopaea.org/forum/index.php?topic=13148.0
    Please take a look at some other languages.
    The older a language the more precise it is.
    Hungarian does not have the ambiguity like English.

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  10. 10. jtdwyer 6:15 pm 04/8/2010

    aniko – Very good point – English might best be considered an amalgamation of several medieval languages – basically every successful invader’s native tongue. Perhaps its extendability is both its strength and its curse.

    My area of expertise has more to do with computers so I’m overstepping my bounds, but the little I know of German includes its extension by verbose descriptive terms. Perhaps this is the price of precision?

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  11. 11. bmo 6:33 pm 04/8/2010

    English is a bad language to use. It has basic grammar, but its vocabulary is an amalgamation of many languages, mostly German, French, Latin and Scandinavian (bloody vikings!)

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  12. 12. bmo 6:43 pm 04/8/2010

    The problem with English is that it’s not just one language. It’s German, French, Latin, Scandinavian, and a bunch of words taken from just about everywhere on the planet. Its vocabulary is twice as large as any other language, giving so many ways to say things compared to other languages. There is ambiguity built into the language itself. Trying to measure brain ambiguity atop this seems an exercise in futility.

    To use one of my favorite quotes from James D. Nicoll,

    "The problem with defending the purity of the English language is that English is about as pure as a cribhouse whore. We don’t just borrow words; on occasion, English has pursued other languages down alleyways to beat them unconscious and rifle their pockets for new vocabulary."

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  13. 13. bmo 6:52 pm 04/8/2010

    Furthermore, on the concept of kludges, evolution works by successive kludges, one atop the other . Anyone who denies this hasn’t taken a long hard look at the ridiculous human body. It is no wonder that language and the mental handling of language are both kludges.


    BMO

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  14. 14. Dan Kaminsky 5:31 am 04/9/2010

    OK, I’m a big fan of these tricks of phrase myself ("I’d like to see a new display" probably being the best of them, though "Times flies like an arrow. Fruit flies like a banana" is the greatest explanation of the problems with natural language processing.)

    However, don’t go off and say silly things like "the brain is not adapted for language". That’s crazy talk, no pun intended. We have a deeply complex grammar acquisition system that vastly outstrips our best efforts at mechanation. Three year old do what computer scientists only dream of. It’s remarkable.

    And, to speak directly to the example, the reason your phrase is hard to parse is because it was specifically generated to be so. That’s fine, but just because you *can* make a broken phrase, does not make phrase engines broken. If you ask a hundred people to express that concept in a single sentence, from a photograph, none will say it in such a confusing way.

    Interestingly, if you have people actually *say* the phrase, you’ll know which interpretation they’re using. One of the defining faults of speech synthesis engines is the inability to accurately manage prosody, the rate and rhythm of speech. Prosody is unwritten, but deeply meaningful. Between prosody, and fairly simple tonality, the meaning becomes obvious:

    "The cop shot the spy, with a revolver"

    vs.

    "The cop shot, the spy with a revolver"

    The rules of printed grammar are only an approximation for speech, and so the second phrase above is never written. But that does not mean it is not part of the language.

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  15. 15. jtdwyer 6:45 am 04/9/2010

    Dan Kaminsky – Well put. Perhaps this will better explain to the linguists what we programmers understand about language. Thanks.

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  16. 16. lowndesw 9:37 am 04/9/2010

    Mr. Marcus, does an M.C. Escher drawing mean that the human mind is NOT well evolved for vision?? It depicts and highlights visual ambiguity, although much more complex than your language example. I submit that the mind’s ability to recognize an ambiguity is proof of (evolutionary) sophistication.

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  17. 17. Dan Kaminsky 11:03 am 04/9/2010

    Oh, I suppose I should be clear that humans say things that, without context, genuinely are confusing. Humans also say things that, even with context, are confusing without clarification.

    And so you know what humans do? They ask for clarification.

    This is the sort of thing that eludes both the programmers and, surprisingly, the linguists. Speech provides "good enough" detail, and if more detail is required, it can be asked for. Bidirectional communication is the rule, oratory and particularly the evolutionarily new orthography and time shifted telecommunication are the exception. No sentence, or even paragraph, contains all the details of a scenario. Requested details need to be asked for — and that’s OK.

    Also, http://xkcd.com/114/ is pretty funny. Don’t take it too seriously though :)

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  18. 18. johnwnorton 6:50 pm 04/9/2010

    Chomsky has abandoned deep structure.

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  19. 19. ralphskinner@hotmail.com 4:20 pm 04/10/2010

    Isn’t the sentence just poor sloppy grammar, the result of an untidy mind producing an ambiguous sentence?
    rephrased, "The spy with the revolver shot the cop" is clear.
    or " The spy shot the cop, who was holding a revolver"
    We need to communicate, not so that the speaker understands, but so that the listener does.

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  20. 20. Grasshopper1 8:48 pm 04/10/2010

    ralphskinner@hotmail.com:

    Exactly. The sentence could be clearer if it was "With the revolver, the spy shot the cop" or "The cop with the revolver was shot by the spy".

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  21. 21. drbobm4 10:06 am 05/10/2010

    Doesn’t overloading in C++ cause the same ambiguity problems? If you examine a subroutine without the full knowledge of the context, you have no idea what has been redefined dynamically. I once had to maintain C++ code where Char * was overloaded into a string constructor.

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  22. 22. Real Linguist 10:24 am 07/10/2012

    “Marcus’s idea that natural human languages are not a product of the well-orchestrated rationality and neat syntactic trees like Noam Chomsky and other linguists have described.”

    Say what? It’s Chomsky’s “neat syntactic trees”, combined with a theory of human parsing of those trees, that PREDICT the ambiguity of sentences like the one with which the article began – and surely Marcus knows this.

    None of the factors mentioned in the article are Chomsky-killers, and as far as I can tell, none of the explanations are anything other than retreads of things Chomsky himself has said about the topic! Even in his infamous interview with Ali G. (check YouTube) he makes Marcus’s point about artificial languages.

    And the analogy to optical illusions is due to Colin Philips of the University of Maryland (for example, http://129.2.53.113/~colin/research/papers/phillips_wagers_lau_2009.pdf), who has developed the analogy extensively in talks and papers (including some for a Sci Am-type audience) over the past decade. Surprising not to see this acknowledged.

    I truly hope the fault is the interviewer’s and not Marcus’s.

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