Chomsky, the Pirahã, and turduckens of the Amazon

A seething dispute has burst back into life with the publication of Language: The Cultural Tool (Economist, New York Times, The Chronicle of Higher Education). I’ve yet to read the book, though I’m pretty sure I will. I admire its author, Dan Everett, as an ex-missionary, who saw the light in those on whom he had sought to foist salvation, as a fieldworker, whose time in the wild is something I can only dream of, and as a defender of one tribe's right to continue its traditions against the depredations of modernity. And I admire his detractors, amongst them, my professor from phd days, David Pesetsky, and my one-time neighbour at MIT, and now near neighbour at UCL, Andrew Nevins.

The Pirahã, and their language, are, Everett believes, different from other groups and other grammars, so different as to threaten Chomsky’s theory of natural language. I wouldn’t describe myself as a card-carrying Chomskian—or as a card-carrying anything. However, my work is inconceivable without the program of research he initiated, and, so, potential Pirahã problems interest me.

Before you venture into foreign terrain, you set your bearings. If all you can see is rainforest, with no clear line of sight to the horizon, then it’s easy to forget your general direction and get caught up in undergrowth and bogged down in mud. So, before I open Everett’s book (or any other), I ask myself what the argument would need to look like to make me reevaluate where my research is headed and why. I’ve found Pirahã very helpful for my work (it’s cited in my last five^(?) papers). Does it really destroy the edifice I’m building?

The Pirahã maelstrom has had two vortices: recursion, and the language–culture connection. Recursion promises/threatens to slay Chomsky, who argues that much of grammar is innate. The language–culture connection promises/threatens to resurrect Whorf, who argues that language shapes how we think. I work on the latter and I’ve written (here, here) on why I choose not to work on the former. For now, I’ll concentrate Chomsky and recursion, because, truth be told, the “Pirahã slays Chomsky” headlines seem to me like errors in elementary reasoning. In other words, the kind of “because” abuse that this blog is named after.

Recipes for recursion
Recursion means sticking something you made earlier into something else. So, preparing perogi (I’m in Kraków just now) isn’t culinary recursion—you’ve just put filling in pastry and left it there—but making borsht with dumplings is—you put something in something to make pirogi and then put your pirogi into your soup. The ultimate in culinary recursion would be turducken, a chicken stuffed inside a duck stuffed inside a chicken (stuffed inside a person).

“Turducken recursion” and “dumpling-borsht recursion” are different and both are found in human language. In “turducken recursion”, you take two things of the same type and put one inside the other—a sentence inside a sentence (Pawel ate the pirogi his mother wanted to sell) or a noun inside a noun (Pawel’s mother’s pirogi). In “dumpling-borsht” recursion, you put something inside something different—a noun inside a verb phrase (ate pirogi) inside a full sentence (Pawel ate pirogi).

Why does recursion matter to Chomsky? Well, one of the ways to think about what he is up to (and how I explain my work at dinner parties) is to pretend the brain is a kind of computer, like an iphone. (Sorry for mixing metaphors, computers with food. But, well, iphones are apples.) Obviously, we share lots of our brain hardware with other animals. But other animals apparently don’t have anything like human languages, not even the vocal, gregarious, communicative ones, not even primates formally schooled in sign languages by eager experimenters. Chomsky has co-written that the crucial difference might be that our hardware at some point became capable of recursion.*

Which recursion does Everett think Pirahã lacks and should Chomsky care? (And why all this talk of “putting inside”, rather than “putting next to”? E.g., why is Pawel’s “inside”, not “next to”, mother’s pirogi?)

Turduckens, iphones, and irrelevance
Everett says that there’s no turducken amongst the Pirahã. No sentence-in-sentence or noun-in-noun. You have duck (Pawel ate pirogi) and you have chicken (His mother wanted their sale), but you’re not getting to ducken, with one inside the other.

But if Everett, and the media, don’t get turducken, they make hoopla. Everett’s claim has been portrayed as a Chomsky-slayer of a fact.** In truth, though, the turducken hunt is a red herring.

My iphone tags my photos to say where I took them. It tells me what’s nearby (cafés, restaurants, museums, shops, ...). It shows me where I am on maps and how to get to where I want to go and which of my friends are nearby. My mother never tags her photos, she never wants to know what’s around her, she never displays herself as a blip on a map, and, if she wants to know if you’re nearby, she calls. But that’s a fact about how my mother has set her iphone up. All location services are off. But that doesn’t mean her iphone can’t provide that information. The computational capacity of our phones is the same, her configuration is just different.

If the Pirahã don’t have turducken sentences, that’s a fact about how their language is configured. It’s not a fact about their hardware. If you kidnapped a Pirahã child (a practice inflicted on numerous indigenous communities) and raised it speaking Portuguese—or, less horrifically, if you exposed it to enough Portuguese for it to grow up bilingual—you’d expect them to be just as capable of learning Portuguese as any other child they were raised with. When Chomsky is concerned with recursion, he is concerned with hardware. The claim is about what brains can learn, not what a particular brain has learned. A dearth of turduckens of the Amazon just doesn’t matter.

Six degrees of separation
Here’s a different path to the same conclusion. “Six degrees of separation”. It’s every Chomskian’s favourite game. You pick some humdrum language, like English, and, with just a tweak here and tweak there, you get yourself up the Amazon without a turducken. The point is to show which exotic delicacies are just familiar fare in fancy sauce. Here’s a pertinent example inspired by the first paper I read in grad school.

What’s the difference between ask and wonder? A normal person will say it’s something about their meanings. Fair enough. But a linguist will it’s about recursion. You can ask what the time is or ask the time. Both are fine. Not so with wonder: you might wonder what the time is, but you can’t wonder the time. Such differences are widespread and don’t appear to depend on meaning. After all, ask and inquire are near synonyms, but I can’t inquire the time. I’m limited to inquiring what the time is.

And now we tweak. Imagine we go, verb by verb, taking everything like ask and making it like inquire, so that it can only combine with a noun, not a sentence-like, “concealed” question. By the time we’re done, English would be on its way to being Pirahã: verbs would no longer be the aperture through which you can turducken one sentence inside another.

Sure, there’d still be relative clauses (Pawel’s mother wanted to sell the pirogi that Pawel ate). But they depend on there being words like that. We could get rid of them too.

Yet, none of this would mean that “English-ish” speakers’ brains had become incapable of recursion. They’d just have turned off their iphones’ location services. No change in hardware, just change in use. So, again, finding a language without turducken recursion is, simply, irrelevant to deciding whether recursion is the crucial component of hardware that makes us computationally competent for language.

Back to borsht and dumplings
We have an expression in English, “to string words together”. This probably reflects what most people think sentences are. Words strung together. One of the major insights of early work by Chomsky & Co is that real generalizations about sentences aren’t phrased in terms of strings. To characterize what is possible a sentence in a language and how possible sentences are related to each other, you don’t talk about which bit follows which other bit. You talk about which two bits were combined first, and about which other bit their combination was combined with next, and so on. Language, in the computery, grammatical sense relevant to Chomsky, is not about strings, it’s about structures.

If Pirahãs’ lack of turducken recursion is irrelevant to Chomsky’s claims, can Everett make hoopla from dumpling-borsht recursion instead? Does Pirahã make us think that its sentences are not built up by this kind of recursion? Three things make me sceptical that Language: The Cultural Tool can show this.

First, the rhetoric. If Pirahã has such sentences, then it is remarkable for what it has, not for what is missing. It would have sentence types that can’t come from recursion, rather than merely not having certain types that do. Yet, all discussion I’ve seen has focused exclusively on what Pirahã lacks. Quite a U-turn.

Second, a point-by-point rebuttal of Everett’s earlier formulations, indicated where Pirahã is similar to Chinese, German, and Hebrew, amongst others. So, if Chinese, etc don’t have sentence types irreconcilable with recursion, then Pirahã probably doesn’t either.

Third, it is not hard to show what a theory cannot do. For all I admire Everett for his post-missionary enlightment, his time in the field, his advocacy of indigenous rights, and his desire to go beyond descriptive work and engage with the foundations of cognition—something I share—I have to recognize that discussion of turduckens and iphones suggests that Everett isn’t the person to do this. The task requires good basic logic and an understanding of the fundamentals of the theories you’re trying to engage with. Turduckens and iphones may seem like silly metaphors, but they reveal, in familiar and concrete terms, Everett’s errors in logic (arguing from irrelevant data) and in understanding (the crucial distinction between linguistic hardware versus its use in a given language). This does not bode well.

Ready for incursion
Not everyone is good at everything. My mother can’t use location services on her iphone, and, frankly, I’m not a fan of the thought of turducken. But my mother doesn’t preach the downfall of Apple and I don’t portray myself as an expert turduckenist.

There’s more to Language: The Cultural Tool than recursion (watch for future posts). But then why all this hoopla about its impact on Chomsky’s view of our mental hardware, if the main subject of the book in all likelihood has nothing of relevance to contribute? Having marshalled my thoughts, I will open the book with a heavy heart. I’ve seen a laudable fieldworker produce lamentable theory before.

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*So all you need to get Dostoyevski is a monkey brain and recursion? No. When Chomsky talks about language, he’s talking only about our computational hardware. Your hardware needs a set of concepts to compute over and, once there are enough people who can also compile their concepts into beautifully articulated thoughts, it’s pretty handy to have some way of getting thoughts out of your head and into theirs: communication—which potentially raises new computational questions, about flattening thoughts built by recursion into sequences sayable/signable one bit at a time. For the curious, I should add that I focus as much on the store of concepts as on building by recursion, if not more. So, I’m not as deeply involved in these issues as some.

**There’s been debate about whether it is a fact at all: he previously found turducken in his neck of the Amazon, and there’s dis-ag-ree-ment about whether he’s been able to reanalyze the examples at stake as separate sentences standing side by side.