Evolang one more time

Footnotes to Plato is a blog run by a philosopher-biologist named Massimo Pigliucci (MP). It has lots of interesting material and I have personally learned a lot by reading it. Currently, MP is writing a multi part commentary on a new book on evolution Darwin’s Unfinished Symphony by Kevin Laland. It’s on the evolution of culture and its impact on the evolution of mind. It is actually a pretty good read and, unlike much of the literature that discusses mind and culture, it does not fall into the continuity thesis trap that takes what humans do to simply be a beefed up version of what other animals do. In other words, it rightly treats the human case as different in kind and asks how this difference might have arisen. I don’t agree with everything Laland proposes, but it starts with the right presuppositions (what humans have really is different) and proceeds from there (see here for some brief discussion).

MP’s latest installment of his running commentary on Laland’s book (here) addresses the evolution of language. In the chapter, Laland surveys traditional accounts for how language arose in the species. Here is the list that MP compiled:

• To facilitate cooperative hunting.
• As a costly ornament allowing females to assess male quality.
• As a substitute for the grooming exhibited by other primate species.
• To promote pair bonding.
• To aid mother-child communication.
• To gossip about others.
• To expedite tool making.
• As a tool for thought.

Laland finds these wanting and adds another contender: language evolved to teach relatives. Laland spends lots of time in previous parts of his book arguing that learning via imitation and observation is a key feature of biological minds and that this power promotes biological success of the evo relevant variety. In this context, it is pretty clear why the pedagogical role of language might find a spotlight: language looks like an excellent medium for molding minds (though parents and teachers might beg to differ regarding how efficient a method it is!). At any rate, Laland’s proposal is that language evolved for instructional purposes, rather than to make tool making easier, or gossip more salacious, or promote pair-bonding or, or, or… Of course, once language arrived on the evo scene it could have served all these other functions as well, but according to Laland that was not what set the whole language thing in motion. Nope, it arose so that one day we could have long and boring faculty meetings at pedagogical institutions like UMD.

MP’s post critically reviews Laland’s proposal and points out that it does not obviously do better on the criteria proposed than do variants of the other rejected approaches. Moreover, MP argues, all these evo scenarios share a common difficulty; because the evolution of language has happened exactly once (i.e. it is a unique evo event) it’s very hard to provide convincing evolutionary evidence of the sort typically on offer for the various alternative scenarios. Here is MP:

For me, though, what makes this chapter the least convincing of those we have read so far is that even if we grant Kevin everything he is arguing for, we are still left, at best, with an hypothetical scenario that falls far short of empirical verification. Yes, maybe language evolved so that we could efficiently teach valuable information to our relatives, and things then went on from there. Or maybe there is a clever variant of one of the other hypotheses now on the table that will be even more convincing than the present analysis. Or perhaps there is yet another scenario that simply nobody has thought up yet. We just don’t know. And to be honest I don’t think we are likely to know any time soon, if ever. Precisely because of a major stumbling block acknowledged by Laland himself: the evolution of language was a unique historical event, and unique historical events are exceedingly difficult (though not impossible) to study.

MP goes on to flag Lewontin’s skepticism regarding the availability of robust evolutionary accounts for cognitive traits given the paucity of footprints in the fossil record left by the exercise of such capacities (see here). Lewontin’s point, that MP endorses, is that it is unlikely that we will ever get enough evidence to build a compelling case for the evolution of any human cognitive trait, including (especially!) language given its biological uniqueness and the faint traces it physically leaves.

I agree with much of this, but I think that it misses the real problem with Laland’s discussion, and with the other scenarios MP catalogues. The big hole in these accounts is that they fail to specify what exactly language is. In other words, the projects fail from the start as they do not sufficiently specify the cognitive capacity whose evolution we are interested in explaining.[1] What exactly is it that has evolved? What are its key properties/characteristics? Only after specifying these does it make sense to ask how it and they arose. Sadly Laland doesn’t do this. Rather he seems to presuppose that we all know what language is and so specifying the relevant capacity of interest in some detail is unnecessary. But linguists know that this is wrong. Language is not a simple thing, but a very complex capacity and so asking how it evolved is asking how all of these complex intricacies came together in humans and only in humans. So, the real problem with Laland (and MP’s discussion) is not just that relevant data bearing on evolutionary scenarios sucks (though it does) but that most of the discussions out there fail to specify what needs explaining. Only after answering this question in some detail can the evolutionary question even be broached coherently.

Let me expand on this a bit. MP starts his comment on Laland as follows:

Despite much talk of animal communication, that’s just what other species do: communicate. Language is a very special, and highly sophisticated, type of communication. Characterized by grammar, capable of recursivity, inherently open ended. Nothing like that exists anywhere else in the animal world. Why?

Given this preamble, the thing that MP (and I assume Laland) thinks needs explaining is how a certain kind of grammar based system of communication arose, with emphasis on ‘grammar’ (after all, this is one key factor that makes human communicative systems unique).

So what features does such a system have? Well, it generates unboundedly many hierarchical structured objects that pair a meaning with an articulation. But this is not all. In addition, its use is very very labile (there is no apparent restriction on the kinds of topics it can be used to “discuss” and it exploits a lexicon several orders of magnitude larger than anything else we find in animal communication systems and whose entries have semantic features quite unlike those we find with other animals. In sum, the syntax of human language, the vocab of human language and the applicability of human language are each unique.

More specifically, as GGers know human Gs embody a very specific form of hierarchical structure (e.g. binary branching, labeled nodes), a very specific form of recursion (e.g. Merge like rather than say FSG like) and human G use is open ended in many different ways (e.g. its use is not stimulus bound (i.e. you can talk about what’s not right before your eyes (viz. independently of the famous 4-Fs) or even actual), the semantics of its atoms are not referentially constricted,[2] its domain of application seems to be topic neutral (i.e. not domain restricted like, say, bee dances or vervet alarm calls)). And all of the above is still a pretty surfacy description of just some of distinctive features of human language (there is nothing quite like morphology evident in other communication systems either). As any GGer can attest, the descriptions available for each of these features that are empirically well motivated are endless.

I could go on, but, even this very cursory and brief description suffices for the main point I want to make: if these are the features that make human language unique then the evolutionary forces Laland lists, including his own, don’t in any obvious way get anywhere near explaining any of them. To wit: How does the fact that language is used to teach realtives or to gossip about them (or others) explain the fact that human Gs are hierarchically recursive, let alone recursive in the specific way that they are? How does the possibility that language promotes pair bounding or can be used to identify predators or to support good ways to hunt explain why human linguistic atoms are not particularly referentially bound? How does the claim that language can guide tool making or teach migration patterns explain why humans can use language in a non-stimulus bound way? How do any of these “functions” explain why the domains of application of human language are so labile? They don’t. Not even close. And that is the real problem. Not only is relevant evidence hard to come by (i.e. Lewontin’s point) but, more importantly, the form of the accounts are conceptually insufficient to explain the (acknowledged) unique features of interest. The problem, in other words, is that the proposals Laland (and MP) survey fail to make contact with the properties that need explaining. And that is far more problematic than simply being empirically hard (maybe, impossible) to verify.

Let me be a little harsher. A standard objection (again from stemming from Lewontin) is that many evolutionary accounts are just-so stories. And this is correct. Many are. And this is indeed a failing. Let’s even say that it is a very serious failing. But whatever their vices, just-so stories do have one vital ingredient missing from the accounts Laland and MP survey: were they accurate they would explain the relevant feature. Why did moths go from light colored to dark when pollution arose? Because the white ones were less able to camouflage themselves and were eaten leaving only the dark ones around. I don’t care if this story is entirely correct (but see here reporting that it is). It has the right form (i.e. if correct it would explain why the moths are speckled dark). So too stories we tell about why polar bears are white and why giraffe necks are long. However, this is precisely what is missing from most EvoLang accounts, including Laland’s. Or more precisely, if the features of interest are the ones that MP notes at the outset (which, recall, MP flags as being what makes human communication systems distinctive), then it is entirely unclear how the gossiping, teaching, cooperating would fuel the emergence of a system that is recursive, non-referential, domain general and stimulus free. So, the accounts fail conceptually, not just empirically. These accounts are not even just-so adequate. And that is a big failure. A very big failure. Indeed, an irreparable one![3]

I could go further (and so I will). Given an FL like ours which produces Gs like ours with generative procedures like ours and vocabulary items like ours it is pretty easy to tell a story as to how such a system could be used to do wonderful things, among others teach, gossip, makes tools, coordinate hunts, discuss movie reviews and more and more and more. That direction is easy. Given the characteristics of the system of language the variable uses it can be deployed in service of is pretty easy to understand. Not so the opposite. Even if teaching or bonding or gossiping is important it is not clear why doing any of these things demands a system with the special properties we find. One could imagine a perfectly serviceable teaching system that did not exploit lexical items with the peculiar semantic properties ours do or did not have generative procedures that allowed for the construction of endlessly hierarchically complex structures or that allowed for vastly different kinds of articulators (hands and tongues) or… You get the point, though, sadly, it seems to be a hard one to get. It is the point that Chomsky has been repeatedly making for quite a while now and it correctly flags the fact that an adequate evolutionary account of a capacity logically require a specification of the capacity whose evolution is being accounted for. This, after all, is the explanadum in any EvoLang account and, as such, is the explanatory target of any admissible explanans. Laland doesn’t spend much time specifying the features that make human language unique (the one’s that MP limns) and so spends no time explaining how his candidate proposal leads to communicative systems with these properties. Not surprisingly, then, the accounts he surveys and the one he provides don’t explain how these capacities could have arisen, let along how they actually did.

So, another discussion of evolang that really gets nowhere. This is nothing new, but it is sad that such smart people (and they are very very smart) are derailed in the same old uninteresting way. We really do know a lot about human language and its unique features. It would be nice if evolutionary types interested in evolang would pay some attention (though I am really not holding my breath).

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[1] The very first comment on MP’s post by saphsin correctly makes this point.

[2] See here for some discussion of this and more specifically Paul Pietroski’s discussions of how little linguistic meaning has to do with truth (e.g. Paul’s contribution here and articles on his webpage here).

[3] I do know of a story that does not make this mistake and that concentrates on trying to explain some features on evolutionary terms. It’s one that Bob Brandon and I provided many many years ago here: From Icon to Symbol:  Some Speculations on the Evolution of Natural Language (1986), Philososphy & Biology. Vol. 1.2 pp.169-189. This speculative paper no doubt suffers from Lewontin’s critique, but at least it tries to isolate different features of the overall capacity and say which ones might be have an available evolutionary explanation. This virtue is entirely due to Robert Brandon’s efforts (he is a hot shot philosopher of biology and a friend).

The logic of adaptation

I recently ran across a nice paper on the logic of adaptive stories (here), along with a nice short discussion of its main points (here) (by Massimo Pigliucci (P)). The Olson and Arroyo-Santos paper (OAS) argues that circularity (or “loopiness”) is characteristic of all adaptive explanations (indeed, of all non-deductive accounts) but that some forms of loopiness are virtuous while others are vicious. The goal, then, is to identify the good circular arguments from the bad ones, and this amounts to distinguishing small uninteresting circles from big fat wide ones. Good adaptive explanations distinguish themselves from just-so stories in having independent data afforded from the three principle kinds of arguments evolutionary biologists deploy. OAS adumbrates the forms of these arguments and uses this inventory to contrast lousy adaptive accounts from compelling ones. Of particular interest to me (and I hope FoLers) is the OAS claim that looking at things in terms of how fat a circular/loopy account is will make it easy to see why some kinds of adaptive stories are particularly susceptible to just-soism. What kinds? Well ones like those applied to the evolutions of language, as it turns out. Put another way, OAS leads to Lewontin like conclusions (see here) from a slightly different starting point.

An example of a just-so story helps to illustrate the logic of adaptation that OAS highlights.  Why do giraffes have long necks? So as to be able to eat leaves from tall trees. Note, that giraffes eat from tall trees confirms that having long necks is handy for this activity, and the utility of being able to eat from tall trees would make having a long neck advantageous. This is the loopiness/circularity that OAS insists is part of any adaptational account. OAS further insists that this circularity is not in itself a problem. The problem is that in the just-so case the circle is very small, so small as to almost shrink to a point. Why? Because the evidence for the adaptation and the fact that the adaptation explains is the same: tall necks are what we want to explain and also constitute the evidence for the explanation. As OAS puts it:

…the presence of a given trait in current organisms is used as the sole evidence to infer heritable variation in the trait in an ancestral population and a selective regime that favored some variants over others. This unobserved selective scenario explains the presence of the observed trait, and the only evidence for the selective scenario is trait presence (168).

In other words, though ‘p implies p’ is unimpeachably true, it is not interestingly so. To get some explanation out of an account that uses these observations we need a broader circle. We need a big fat circle/loop, not an anorexic one.

OAS’s main take home message is that fattening circles/loops is both eminently doable (in some cases at least) and is regularly done. OAS lists three main kinds of arguments that biologists use to fatten up an adaptation account: comparative arguments, population arguments, and optimality arguments. Each brings something useful to the table. Each has some shortcomings. Here’s how OAS describes the comparative method (169):

The comparative method detects adaptation through convergence (Losos 2011). A basic version of comparative studies, perhaps the one underpinning most state- ments about adaptation, is the qualitative observation of similar organismal features in similar selective contexts.

The example OAS discusses is the streamlined body shapes and fins in animals that live in water. The observation that aquatic animals tend to be sleek and well built for moving around in water strongly suggests that there is something about the watery environment that is driving the observed sleekness.  As this example illustrates, a hallmark of the comparative method is “the use of cross-species variation” (170). The downside of this method is that it “does not examine fitness or heritability directly” and it “often relies on ancestral character state reconstructions or assumptions of tempo and mode that are impossible to test” (171, table 1).

A second kind of argument focuses on variations in a single population and sees how this affects “heritability and fitness between potentially competing individuals” (171). These kinds of studies involve looking at extant populations and seeing how their variations tie up with heritability. Again OAS provides an extensive example involving “the curvature of floral nectar spurs” in some flowers (171) and shows how variation and fitness can be precisely measured in such circumstances (i.e. where it is possible to do studies of  “very geographically and restricted sets of organisms under often unusual circumstances” (172)).

This method, too, has a problem.  The biggest drawback is that the population method “examines relatively minor characters that have not gone to fixation” and “extrapolation of results to multiple species and large time scales” is debatable (171, table 1). In other words, it is not that clear whether the situation in which population arguments can be fully deployed reveal the mechanisms that are at play “in generating the patterns of trait distribution observed over geological time and clades” because it is unclear whether the “very local population phenomena are…isomporphic with the factors shaping life on earth at large” (172).

The third type of argument involves optimality thinking. This aims to provide an outline of the causal mechanisms “behind a given variant being favored” and rests on a specification of the relevant laws driving the observed effect (e.g. principles of hydronamics for body contour/sleekness in aquatic animals). The downside to this mode of reasoning is that it is not always clear what variables are relevant for optimization.

OAS notes that adaptive explanations are best when one can provide all three kinds of reasons (as one can in the case, for example, of aquatic contour and sleekness (see figure 4 and the discussion in P). Accounts achieve just-so status when none of the three methods can apply and none have been used to generate relevant data. The OAS discussion of these points is very accessible and valuable and I urge you take a look.

The OAS framing also carries an important moral, one that both OAS and P note: if going from just-so to serious requires fattening with comparative, population and optimization arguments then some fashionable domains of evolutionary speculation relying on adaptive consideration are likely to be very just-soish. Under what circumstances will getting beyond hand waving prove challenging? Here’s OAS (184, my emphasis):

Maximally supported adaptationist explanations require evidence from comparative, populational, and optimality approaches. This requirement highlights from the outset which adaptationist studies are likely to have fewer layers of direct evidence available. Studies of single species or unique structures are important examples. Such traits cannot be studied using comparative approaches, because the putatively adaptive states are unique (cf. Maddison and FitzJohn 2015). When the traits are fixed within populations, the typical tools of populational studies are unavailable. In humans, experimental methods such as surgical intervention or selective breeding are unethical (Ruse 1979). As a result, many aspects of humans continue to be debated, such as the female orgasm, human language, or rape (Travis 2003; Lloyd 2005; Nielsen 2009; MacColl 2011). To the extent that less information is available, in many cases it will continue to be hard to distinguish between different alternative explanations to decide which is the likeliest (Forber 2009).

Let’s apply these OAS observations to a favorite of FoLers, the capacity for human language. First, human language capacity is, so far as we can tell, unique to humans. And it involves at least one feature (e.g. hierarchical recursion) that, so far as we can tell, emerges nowhere else in biological cognition. Hence, this capacity cannot be studied using comparative methods. Second, it cannot be studied using population methods, as, modulo pathology, the trait appears (at least at the gross level) fixed and uniform in the human species (any kid can learn any language in more or less the same way). Experimental methods, which could in principle be used (for there probably is some variation across individuals in phenomena that might bear on the structure of the fixed capacity (e.g. differences in language proficiency and acquisition across individuals) will, if pursued, rightly land you in jail or at the World Court in the Hague. Last, optimization methods also appear useless for it is not clear what function language is optimized for and so the dimensions along which it might be optimized are very obscure.  The obvious ones relating to efficient information transmission are too fluffy to be serious.[1]

P makes effectively the same point, but for evo-psych in general, not just evo-lang. In this he reiterates Lewontin’s earlier conclusions. Here is P:

If you ponder the above for a minute you will realize why this shift from vicious circularity to virtuous loopiness is particularly hard to come by in the case of our species, and therefore why evolutionary psychology is, in my book, a quasi-science. Most human behaviors of interest to evolutionary psychologists do not leave fossil records (i); we can estimate their heritability (ii) in only what is called the “broad” sense, but the “narrow” one would be better (see here); while it is possible to link human behaviors with fitness in a modern environment (iii), the point is often made that our ancestral environment, both physical and especially social, was radically different from the current one (which is not the case for giraffes and lots of other organisms); therefore to make inferences about adaptation (iv) is to, say the least, problematic. Evopsych has a tendency to get stuck near the vicious circularity end of Olson and Arroyo-Santos’ continuum.

There is more, much more, in the OAS paper and P's remarks are also very helpful. So those interested in evolang should take a look. The conclusion both pieces draw regarding the likely triviality/just-soness of such speculations is a timely re-re-re-reminder of Lewontin and the French academy’s earlier prescient warnings. Some questions, no matter how interesting, are likely to be beyond our power to interestingly investigate given the tools at hand.

One last point, added to annoy many of you. Chomsky’s speculations, IMO, have been suitably modest in this regard. He is not giving an evolang account so much as noting that if there is to be one then some features will not be adaptively explicable. The one that Chomsky points to is hierarchical recursion. Given the OAS discussion it should be clear that Chomsky is right in thinking that this will not be a feature liable to an adaptive explanation. What would “variation” wrt Merge be? Somewhat recursive/hierarchical? What would this be and how would the existence of 1-merge and 2-merge systems get you to unbounded Merge? It won’t, which is Chomsky’s (and Dawkins’) point (see here for discussion and references). So, there will be no variation and no other animals have it and it doesn’t optimize anything. So there will be no available adaptive account. And that is Chomsky’s point! The emergence of FL whenever it occurred was not selected for. Its emergence must be traced to other non adaptive factors. This conclusion, so far as I can tell, fits perfectly with OAS’s excellent discussion. What Chomsky delivers is all the non-trivial evolang we are likely to get our hands on given current methods, and this is just what OAS, P and Lewontin should lead us to expect.

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[1] Note that Chomsky’s conception of optimal and the one discussed by OAS are unrelated. For Chomsky, FL is not optimized for any phenotypic function. There is nothing that FL is for such that we can say that it does whatever better than something else might. For example structure dependence has no function so that Gs that didn’t have it would be worse in some way than ones (like ours) that do.

Somethings you might enjoy

I read a blog managed by Massimo Pigliucci called Scientia Salon. He posts himself and carries interesting stuff on the current evo biology that I find informative.  At any rate he has recently posted two things that you might enjoy.

First, there is this piece on the Formal Darwinism Project. The aim seems to be to provide a rational basis for the kind of teleological/functional/good design thinking that evo theorists find so compelling (and, it appears given the paper, they find it so for some good reasons). Of course, such thinking is hardly foolproof and there are lots of times when it fails. The idea seems to be to ground it and see where it works and where not. Interestingly, part of the effort is to find those circumstances in which not knowing much about the genetics won't make much of a difference.  This is where the "phenotypic gambit" works. Here's the author:

In 1984, I coined the term ‘Phenotypic Gambit’ for the research strategy of studying organisms in ignorance of the actual genetic architecture of the trait in question … The Phenotypic Gambit articulates the assumption that is usually made implicitly in this work, and the formal darwinism project aims to understand better why and how the gambit works when it does, and also to identify and understand those cases in which the gambit fails.

Interestingly, it seems that much (indeed, it seems, most) work in evolutionary is done in complete and utter ignorance of the relevant genetics, on the assumption that in many cases "the genetic details, which aren't known, are unlikely to matter" (quote from paper post links to. It's behind a paywall, but many can get it through their university libraries). Here's another quote from Jarrold Hadfield (170):

If you exclude simple Mendelian traits…then we know very little about the genetic basis of most traits.

Why do I mention this? Well, there is a huge amount of skepticism regarding Darwin's Problem. Some of this stems from the fact that we know little about the genetics underlying language so that thinking about it is just so much hand waving. This was a theme at the Athens conference (in fact, I might have been the one person there who did not buy into this) and it was also a theme discussed on this blog here. However, if this article is right, then it seems that it is a problem way beyond anything having to do with DP as applied to FL. It is very very common in evo investigations. And if it is ok for people studying stuff in animals to make the Phenotypic Gambit (as a useful idealization and always ready to retreat when it proves wrong) then why not in the study of FL/UG as well.

In our case, the gambit amounts to assuming that a "simple" phenotypic description will translate into a simple genetic one. This may be wrong, but it seems to be widely adopted despite the obvious problems. In short, it seems that perhaps (see the hedging here) those interested in DP are doing exactly what the state of the evo art recommends: do the best you can given that we know little about the genetics of anything bigger than bacteria. At the very least, the phenotypic gambit, the assumption that the genetics, once understood, will not greatly distort the conclusions drawn from phenotypic reasoning, is both widespread in biology and useful. Of course, maybe these people aren't doing real biology either. Maybe.

Second, there is this provocative post by Pigliucci in funding for science research. He points out that the question of why society should fund pure science is one that needs to be seriously addressed. Moreover, the standard arguments seem to lack much serious empirical grounding once one gets beyond anecdote.  Linguists should think this question through given that more and more of our work is being supported by gvmt grants or foundations. Why should they fund it?  The argument that one day it will help us cure cancer is not that compelling. What is more compelling is that I actually no of virtually no interesting applied (aka translational) work that does not rely on huge amounts of work funded for less instrumental ends.  In other words, from the little I know, most translational research presupposes results gained from publicly funded efforts. The results are easy enough to spot all around us today. The  last breakthroughs are almost always based on gvmt sponsored work (think internet, iPhone, computer, most of current molecular biology etc.). As I noted sometime ago, the computer would not exist but for the work of logicians interested in the foundation of mathematics. The fact is that most of the wonders around us hail from curiosity driven research. And what is also clear is that the fruits of this work would have been virtually impossible to anticipate ex ante.

Pigliucci touches on one other theme that is noteworthy: the bullshittification of grant applications when the one needs to defend ones work in purely instrumental terms. His observations quoted here fit well with my own:

When I was submitting grant proposals to NSF, I was required to also fill out a section about the “broader impact” of my research (which was on genotype-environment interactions in a species of weedy plants). It was always an afterthought, a boilerplate that got copied from proposal to proposal. And so were those of most of my colleagues. The reason is that — even though I was actually studying something for which practical applications were not at all far fetched (e.g., weed control, invasive biology), that’s not why I was doing it. I was doing it because I had a genuine basic curiosity about the science involved. Indeed, had NSF really only funded basic research that had a direct link to applications I could have done pretty much the same thing on a different model system, say a weed or an invasive species with well demonstrated commercial effects. And mine was by far not even close to being the most narrowly focused and idiosyncratic piece of science carried out within my own department, let alone in the US at large.

At any rate, the piece raises important issues: why should anyone fund our work? Why should they care? Here we need to be able to elaborate what we do for a wider audience in terms that they can understand. I've discussed this before (here). Pigliucci's discussion pushes the question further. It is not unreasonable for people to ask why we should keep paying. One answer is that the problems we try to investigate are intrinsically interesting. I believe that this is right. And I have a spiel. Do you? If not, get one!