A paper that deserves classic status

Phil Lieberman has written an important piece (here) (henceforth PL). It’s a reply to the Bolhuis, Tattersall, Chomsky and Berwick (BTCB) piece on Merge and Darwin’s Problem (discussed here). What makes Lieberman’s piece important is that it is an almost prefect example (being short not among its least attractive qualities) of the natural affinities that ideas have for one another. In this case, the following conceptions exert strong mutual attractions:

(i)             Language as communication

(ii)           Associationism

(iii)          Anti-modularity (i.e. cognition as general intelligence)

(iv)          Gradualist conceptions of natural selection (NS) as the sole (or most important) mechanism of evolution

(v)           Connectionist models of the brain. Though they may not strictly speaking imply one another, chances are that if you are attracted to one you will find the others attractive as well. Why is this?

Lieberman’s paper offers one line of argument that links these conceptions together. I would like to review these links here for I believe PL’s main message is important, precisely because it is wrong. As many of you may have noticed, I am of the opinion that Empiricism is a coherent, intellectually tight position with wide ranging (unfortunate) implications both for the study of language, mind and brains and for scientific methodology more generally. I believe that the degree that this is so is often underestimated. PL provides an example of its various strands coming together. I did not find the piece particularly persuasive, nor particularly well crafted. However, it is often in less worried versions of a set of ideas that one can more clearly see their underlying logic. PL offers us an opportunity to examine these. Hence the importance of the piece. So let’s dive in.

Concerning language, say you believe (iv) (as PL puts it: “Language evolved over millions of years”) then for NS to work its magic there has to be something common between our ancestors and ourselves. As it is evident that what "we" do with "language" is entirely different from what “they” do with it, to tell an NS story we need to find some common property between what we do and they do language wise that NS can focus on to get us from them to us. The only plausible common factor is vocalization with the common purpose of communication. So if you like (iv) you will naturally like (i). And vice versa: if you see language’s “primary role as communication” then you can see a way of understanding what we do as emerging from what they do given a sufficiently long time span (viz. million of years).

So, (i) and (iv) come as a bundle. Moreover, both of these suggest (iii). How so? Well ‘modularity’ is the term we use to mark a qualitative difference. The visual system is different in kind from the visual (changed 2/16/15) auditory system. Each has its own specialized operations and primitives. Vision and  audition are not reflections of some common “sensing” system. Thus, modules are mental organs with their own distinctive and specialized properties (i.e. properties that are not like those found elsewhere). But these are just the kinds of things that NS per se is not that good at explaining the origins of all by itself. NS is good at finding the genetic gold among the genetic dross. It in itself provides no account for how the gold got there in the first place. In other words, given variation NS can enhance some traits and demote others. However, this presupposes a set of selectables and if what emerges is qualitatively distinctive from what came before, then NS by itself cannot account for its emergence. Some other source for the novelty needs to be found. As modules are precisely such novelties, if you buy into (i) and (iv), then you will also purchase (iii).

So no modules. But that strongly suggests that all cognition is of a piece. After all if they are not qualitatively different they are more or less the same (and NS and associationism love more-or- less-ism with all of its lovely hill climbing). In other words, the belief that the basic mechanisms of thought are effectively the same all over leads directly to (ii), associationism. What better universal cognitive glue than “imitation and associative learning”? So, we have paths that conceptually relate (i) and (ii) and (iii) and (iv).

A side note: The conceptual link between (ii) and (iv) has long been noted. For example, Chomsky commented on the common logic between NS accounts and classic associationism in his review of Skinner. Indeed, Skinner argued (as Chomsky noted) that one of the virtues of behaviorism, his species of associationsim, was its affinity with NS.

What’s the common core? Well, both NS and associationism are species of environmentalism. They share the common conceit that structure is largely a reflex of environmental shaping, a process that requires repeated environmental feedback to guide the process of evolution or learning (e.g. hill climbing with back propagation). In one case what’s shaped is the genome, in the other the mind. However both conceptions assume that the structure of the “inside” is a pretty direct function of the shaping effects of the outside. The common logic was recently detailed once again by Fodor and Piatelli-Palmarini (here). So it is not particularly surprising that aficionados of one will be seduced by the other, which means that those partial to  (ii) will find (iv) attractive and vice versa.

So all that’s left is (v), and as Gallistel has shown, connectionism is just the brain mechanism of choice for associationism (see, e.g. here and here). So we can complete the circle. Starting from any of (i)-(v), we stand a pretty good chance of getting to all of the others. The link is not quite deductive, but the affinities are more than mildly attractive.

PL manages to add one more little bedfellow to this gang of five. These mutually supporting ideas also induce an adherent inability to distinguish Chomsky from Greenberg Universals. As I’ve been wont to note before (here), Empiricism and Associationism can plausibly accommodate the latter but not the former. And, right on cue, the PL paper makes the connection. Language variation (i.e. absence of Greenberg Universals) is taken to prove the impossibility of a Universal Merge operation (i.e. a Chomsky Universal). Thus, the PL paper argues that the fact that languages differ implies that they cannot be underlyingly the same, the presupposition being that identity/similarity in surface patterning is a necessary feature of a linguistic universal. If you are an Empiricist, it really is hard to see how to distinguish Chomsky from Greenberg.

There is much more nostalgic material in this little piece: Piraha makes a cameo appearance near the end (you could have predicted this, right?), as do FoxP2, Kanzi the bonobo, the Gardner chimps, and various unfounded assertions about the recursive properties of dancing. None of the claims are argued for really, simply asserted. However, given (i)-(v) you can construct (and then deconstruct) the arguments for yourself. The piece is not convincing, but, IMO, as convincing as it can be given its starting points.

BTCB reply to PL (here) and make all the obvious points. IMO, they are completely correct (but I would think this wouldn’t I?). BTCB identify a property of language that they want an evolutionary account for (viz. hierarchical discrete recursion (HDC)). They want to know how HDC of the kind we find in natural could have evloved. They note that this is not the only question relevant to the evolution of language, but it is a good question and a pretty good place to start. Curiously, this seems to be the one question that most EVOLANG types really don’t want to address. And it is clear why: it is the one that least (in the sense of 'not at all') lends itself to standard NS styles of explanation. It points to a cognitively distinctive species specific system whose properties seem sui generic.  If correct (and right now there is no reason to think it is not) it argues that natural language really is cognitively different, at least in part. PL can’t believe this (why? See (i)-(v) above), as also seems to be true for most everyone else in the EVOLANG bidness. But it is, and that’s the main problem with PL’s little rebuttal. It fails to even recognize, let alone tackle, the hard EVOLANG problem: how did HDC arise?

To end: PL’s is a very useful paper. It is an object lesson in how ideas come in bunches and exhibit a certain logic and affinity. (i)-(v) above are particularly incestuous. PL’s paper exhibits these affinities. His argument is weak and that’s because (i)-(v) are wrong. And producing a very weak argument that exposes very weak premises is a very useful thing to do. PL has done us all a great favor in replying to BTCB. Take advantage of his generosity and learn.

A concise discussion of Darwin's Problem

A bunch of the good guys (Bolhuis, Tattersall, Chomsky and Berwick (BTCB) have a new paper out in Plos Biology that reviews in a concise manner the logic relating the Minimalist Program (MP) and Darwin’s problem (DP). The paper is worth knowing about for several reasons, not the least being that it came out in Plos Biology, an important venue for bio research. It also is a nice short paper that one can give to friends (I in fact just sent it to an econ buddy of mine) if they are curious about what kinds of BIG issues linguists are trying to address.

For the cognoscenti, the discussion will be quite familiar (though if you are like me and love greatest hits albums, this will be a pleasure to read). It starts where all good evo discussions have to start; with a characterization of the faculty whose emergence one is interested in explaining). BTCB hits all the required notes: language is not speech, nor an instrument for communication. Or, more precisely, externalization is not relevant to the key features the “language faculty per se” (1).  Rather (and get ready for the surprise), “language is a computational cognitive mechanism that has hierarchical syntactic structure at its core…” (1). In other words, the target of evo explanation in the domain of language is how this generative capacity came to be fixed as a biological property of humans. [1]

With the target of explanation specified, BTCB goes on to make the observation that MP has the properties required to allow an assault on this problem. What the paper does not say (but I think is important), is that prior to the emergence of MP linguists had little to contribute (or more accurately, little they could contribute) to the question of how FL evolved. How does MP advance the evo issues? By providing “an extremely simple” account of human syntax, “simple” being the key feature.  In other words, what MP affords (or, at least, promises) is a characterization of syntax as comprising a single simple combinatoric operation, which, when combined with the “general cognitive requirement for computationally minimal or efficient search,” “suffices to account for much of human language syntax” (p. 1-2).  In other words, what MP does is so simplify the structure of FL that it makes it possible to understand how an FL with these characteristics might have come into being. Or, to put this another way, prior to MP the understood structure of FL was so complex and sui generis (had so many moving and interacting parts) that it was impossible to see how it could have evolved.  In short, the only hope we have of providing an account of how FL arose in the species is if FL has an MPish structure. Note, that this is very much a conceptual argument. Evo details, as BTCB notes, will be very hard to come by, as they note and we return to anon.

BTCB proceeds to observe two nice features (consequences?) of a simple FL: (i) it could have emerged all at once, and (ii) it would have remained stable given its lack of moving parts. As BTCB note, there is evidence that both these features are correct.

The second (viz. that FL has remained largely unchanged since its emergence) is almost certainly correct as “there is no doubt that a normal child from England raised in northern Alaska would readily learn Eskimo-Aleut, or vice versa” (p. 2). In other words, so far as we can tell all humans (even those from isolated communities) share a common FL as witnessed by the fact that any human can learn any language if properly environmentally situated. As BTCB notes, the uniformity and stability of FL “points to the absence of major evolutionary change since the emergence of the language faculty” (2). It also, IMO, supports the idea that FL is not itself the end-product of selection for if it were we might expect to see continuing differential changes in FL’s structure, with different groups having slightly different FLs facilitating the use and acquisition of some languages at the expense of others. We, apparently, do not see this, which suggests that all FLs are of a piece, which would make sense if they were very simple in an MPish sort of way.

Let’s now turn to the issue of rapid emergence. Finding evidence relevant to making evo claims turns out to be very (very very very…) difficult, with the available evidence being “quite indirect.” BTCB reiterates a point made by Lewontin long ago (here) that getting non-trivial evidence that bears on the issues is not at all easy. In fact, BTCB identifies exactly one kind of useful type of evidence for dating the emergence of “language,” and it comes from archeology. The evidence is the sudden widespread explosion of symbolic artifacts in the archeological record roughly 100 thousand years ago. These artifacts have been used as “proxies” for language, the idea being that the emergence of language (and the cultural evolution it supports?) is the main causal factor behind this sudden rise in symbolic artifacts. This, BTCB emphasizes is “quite indirect” evidence for the presence of a fully operational FL, but it is all we’ve really got given the exigencies of finding the standard kinds of relevant evidence commonly used to advance reasonable evo hypothesizing (again, see Lewontin on this for an elaborate and useful review). This archeological evidence (which I assume that Tattersall is responsible for reviewing here) points to a relatively rapid emergence of FL about 100kya (p. 3). The artifact-proxies for language emerge in the archeological record all at once, in many places and quickly. It suggests that whatever took place did not happen gradually (contra many standard Darwinian tropes). Note, the possibility of rapid emergence is conceivable if what made it possible is a simple addition to an otherwise available system, the kind of system MP aims to provide.

To wrap up: BTCB has two important virtues: (i) It illustrates the strong conceptual bond between MP and DP, and (ii) it illustrates how meager the actual data bearing on evo concerns in the domain of language really are. As a matter of facts we still know next to nothing about how FL emerged. Moreover, we are unlikely to learn anything in the near future about the details given how hard it will be to find relevant evidence bearing on the issue. Nonetheless, BTCB shows that some progress has been made, but mainly from the linguistic/conceptual side. I think that BTCB is right in thinking that MP is a conceptually important move forward, as any conceivable account of the mergence of FL will require something like MP. So if you are Darwin enchanted then you’d better become a card- carrying minimalist. It’s the only hope, even if it is a faint one.

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[1] The paper also makes some nice methodological observations concerning what an evolutionary account can and cannot hope to deliver. BTCB observe that as a matter of logic, evo accounts cannot deliver explanations of how what has evolved actually works.  This is why a grammatical characterization of FL is so vital. Evo accounts need specifications of mechanisms. Specifications of mechanism can proceed quite happily without evo accounts of how they got there.  For further discussion of this point, see the Bolhuis and Wynne paper referred to in the notes. It’s worth a read.