Got Culture?

In the last chapter of Dehaene’s Reading the Brain he speculates about one of the really big human questions: whence culture? The books big thesis, concentrating on reading and writing as vehicles for cultural transmission, is the Neuronal Recycling Thesis (NRT). The idea is simple; culture supervenes on neuronal mechanisms that arose to serve other ends. Think exaptation as applied to culture.  Thus, reading and writing are underpinned by proto letters, which themselves live on ecologically natural patterns useful for object recognition.  So too, the hope goes, for the rest of what we think of as culture. However, as Dehaene quickly notes, if this is the source, and “we share most, if not all of these processors [i.e. recycled structures NH] with other primates, why are we the only species to have generated immense and well-developed cultures” (loc 4999). Dehaene has little patience for those who fail to see a qualitative difference between human cultural achievements and those of our ape cousins.

…the scarcity of animal cultures and the paucity of their contents stand in sharp contrast to the immense list of cultural traditions that even the smallest human groups develop spontaneously. (loc 4999)

Dehaene specifically points to the absence of “graphic invention” in primates as “not due to any trivial visual or motor limitation” or to a lack of interest in drawing, apparently (loc 5020). He puts the problem nicely:

If cultural invention stems from the recycling of brain mechanisms that humans share with other primates, the immense discrepancy between the cultural skills of human beings and chimpanzees needs to be explained. (loc 5020)

He also surveys several putative answers, and finds them wanting. His remarks on Tomasello (loc 5046-5067) seem to me quite correct, noting that though Tomasello’s mind reading account might explain how culture might spread and its achievements retained cross generationally:[1]

…it says little…about the initial spark that triggers cultural invention. No doubt the human species is particularly gifted at spreading culture – but it is also the only species to create culture in the first place. (loc 5067, his emphasis)

So what’s Dehaene’s proposal?

My own view is that another singular change was needed - the capacity to arrive at new combinations of ideas and the elaboration of a conscious mental synthesis (loc 5067).

This is quite a mouthful, and so far as I can see, what Dehaene means by this is that our frontal lobe got bigger and that this provided a “”neuronal workspace” whose main function is to assemble, confront, recombine, and synthesize knowledge” (loc 5089).

I don’t find this particularly enlightening. It’s neuro-speak for something happened, relevant somethings always involving the brain (wouldn’t it be refreshing if every once in a while the kidney, liver or heart were implicated!). In other words, the brain got bigger and we got culture. Hmm. This might be a bit unfair. Dehaene does say more.

He notes that the primate cortex, in contrast to ours, is largely modular, with “its own specific inputs, internal structure, and outputs.” Our prefrontal cortex in contrast “emit and receive much more diverse cortical signals” and so “tend to be less specialized.” In addition, the our brains are less “modular” and have greater “bandwidth.” This works to prevent “the division of data and allows out behavior to be guided by any combination of information from past or present experience.” (loc 5089)

Broken down to its essentials, Dehaene is here identifying the demodularization of thought as the key ingredient to the emergence of culture. As he notes (loc 5168), in this he agrees with Liz Spelke (and others) who has argued that the general ability to integrate information across modules is what spices up our thinking beyond what we find in other primates.  Interestingly for my purposes here, Spelke ties this capacity for cross module integration to the development of linguistic facility (see here).

This assumption, that language is a necessary condition for the emergence of the kind of culture we see in humans is consistent with the hypothesis Minimalists have been assuming (following people like Tatersall (here)) that the anthropological “big bang,” which occurred in the last 25-50,000 years, piggy backed on the emergence of FL in the last 50-100,000 years. Moreover, it’s language as module buster that gets the whole amazing culture show on the road.

But what features of language make it a module buster?  What allows grammar to “assemble and recombine” otherwise modular information? What’s the secret linguistic sauce?

Sadly, neither Dehaene nor Spelke say.  Which is too bad as me and my lunch buddies (thx Paul, Bill) have discussed this question off and on for several years now, without a lot to show for it. However, let me try to suggest a key characteristic that we (aka I) believe is implicated. The key is syntax!

The idea is that FL provides a general-purpose syntax for combining information trapped within modules.  Syntax is key here, for I am assuming (almost certainly wrongly, so feel free to jump in at any point) what makes information modular is some feature of the module internal representations that make it difficult for them to “combine” with extra-modular information. I say syntax for once information trapped within a module can combine with information in another module it appears that, more often than not, the combination can be interpreted. Thus, it’s not that the combination of modularly segregated concepts is semantically undigestible, rather the problem seems to be getting the concepts to talk to one another in the first place, and, I take this to mean, to syntactically combine. So module busting will amount of figuring out how to treat otherwise distinct expressions in the same way. We need some kind of abstract feature that, when attached to an arbitrary expression, allows it to combine with any other expression from any other module.  What we need, in effect, is, what Chomsky called, an “edge-feature,”  (EF) a thingamajig that allows expressions to freely combine.

Now, if you are like me, you will not find this proposal a big step forward for it seems to more name a solution than provide one. After all, what can EFs be such that they possess such powers?  I am not sure, but I am pretty confident that whatever this power is it’s purely syntactic. It is an intrinsic property of lexical atoms and it is an inherited property of congeries of such (i.e. outputs of Merge).  I have suggested (here) that EFs are, in fact, labels, which function to close Merge in the domain of the lexical items (LIs). In the same place I proposed that labeling is the distinctively linguistic operation, which in concert with other cognitively recycled operations, allowed for the emergence of FL.

How might labels do this?  Good question. An answer will require addressing a more basic question: what are labels?  We know what they must do: they must license the combination both of lexical atoms and complexes of such.  Atomic LIs are labels.  Complexes of LIs are labeled in virtue of containing atomic ones. The $64,000 question (doesn’t sound like much of a prize anymore, does it?) is how to characterize this.  Stay tuned.

So, culture supervenes on language and language is the recycling of more primitive cognitive operations spiced with a bit of labeling. Need I say that this is a very “personal” (read “extremely idiosyncratic and not currently fashionable”) view?  Current MP accounts are very label-phobic.  However, the question Dehaene raises is a good one, especially for theories like MP that presuppose lots of cognitive recycling.[2]  It’s not one whose detailed answer is anywhere on the horizon. But like all good questions, I suspect that it will have lots of staying power and will provide lots of opportunities for fun conversations.

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[1] It’s good to see that Tomasello is capable of begging the interesting question regardless of where he puts his efforts.

[2] See discussion in the comments I had with Jan Koster about this my previous post (here).

A Teachable Moment

There is an interesting discussion going on in the comments section of the “Darwin’s Problem” post (here).  In fact, I believe that it offers a useful teachable moment, one that I would like to exploit.  Doing so requires stepping back from the argument and considering its logic; what premises drive what argumentative moves to what conclusions and why.  I believe that the revealed dialectic is instructive for it shows that the “debate,” such as it is, is less about theoretically and empirically difficult substantive issues than about a certain skepticism about the facts.  Let me explain.[1]

Step 1: For a linguist, Darwin’s Problem starts with the identification of the explanadum (that which needs explaining).[2] And qua linguist I have a pretty good idea what that is, viz. the structure of UG.  What I want to know is how UG arose in the species, i.e. how it got there? Moreover, qua linguist, I am confident that I have a pretty good idea what UG looks like. I may not know everything, but I know a goodly amount about UGs basic features. Standard versions of GB theory provide a reasonable compendium of these. Though for current purposes, I would not be parochial. If you prefer alternative accounts, GPSG, LFG, HPSG, RG etc. that’s fine. For present purposes these all make the same relevant distinctions, viz. they have roughly the same hierarchy and locality licensing conditions on movement and construal, the same basic endocentric phrase structure, the same basic ideas about crossover etc.  In other words, broadly speaking, most grammarians agree about the general lay of the grammatical land.

Why such consensus? Because the facts dictate it.  Linguists have done a lot of work over the last 60 years and looked at a lot of languages and the general conclusion is that all grammars embody these properties (all specific Gs conform to UG). Thus, Island effects are real, as are Principle A, B and C effects, Weak and Strong Cross Over effects, Fixed Subject effects, Tensed S effects etc.  Theories differ not on the whether but on the how/why. So, for linguists what the basic features of grammars are is not really a wide open question and that’s why Darwin’s Problem for a generative linguist, starts with a description of the target of explanation being something like a UG as described along roughly GB lines.

Step 2: Given this, Darwin’s problem is to explain how it arose. Now other additional facts serve as added boundary conditions. These are not facts that linguists have discovered, but ones found by anthropologists and biologists. These include those that the BFCB paper discuss; the two biggies being that language arose in the species about 100,000 years ago, that whatever arose was fixed in the species before the move out of Africa about 80,000 years ago.  Another biggie is that what humans do linguistically is unique. No other animals (no fish, no fowl, no beasts, no bugs) do it even remotely like we do it. These three facts require that whatever took place was effectively unique and happened very rapidly as measured on evolutionary time scales. 

Step 3: Combining steps 1 and 2 we have the following problem: explain how something with roughly the properties of GB could have arisen in about 20,000 years about 100,000 years ago. That’s Darwin’s Problem for a linguist.  Note, if you think that this arose through natural selection (NS) by modifying some non-linguistic cognitive capacities other animals have/had then the job is to show how something with roughly the properties of GB could have arisen from these other capacities by the sort of modifications NS favors in the time period identified. So, if e.g. you think that GB arose by modification of the capacity to plan as exhibited in non-linguistic animals then starting with a description of planning capacities show how NS would have modified these in response to specified environmental “problems” to get something with roughly the properties of GB, viz. it’s kind of locality conditions, it’s kind of phrase structure rules, it’s kind of hierarchical dependencies, it’s kinds of displacement, etc.  If this can be done, great.  Really that would be terrific. What is not great and very unterrific (at least given these background conditions) is to start from the assumption that we really don’t know much about UG for this does not answer the question posed but answers a different question. Again, let me elaborate.

Many people reject the question posed above because they already know what kind of explanation is required. So, many think that NS is the only viable evolutionary explanation for complex capacities.  And, because NS accounts have had (at least till now) no notable success in accounting for the emergence of something with the GBish properties of UG, they conclude that language cannot have these properties.[3] In other words, they deny what I would call, simply, the facts. For my money, this makes such individuals the linguistic equivalents of climate change deniers. There are some out there that either deny that the climate is getting warmer and/or that human activity is a prime cause of this warming.  Similarly, there are those that deny that language has hierarchical structure, is governed by structure dependent locality conditions and has structure dependent processes.  Such people do exist. From where I sit, they have nothing to add to the present discussion for the same reason that climate change deniers have nothing to add to the climate change discussions. To play the game, you need to acknowledge the facts. And that’s where the minimalist program is so interesting: it tries to provide a scenario that respects these facts. It includes a mutation or two (aka “miracles”), because there appears to be no way to get to what we know to be the properties of UG without them. It tries to unify the various GB modules for this reduces the number of “miracles” needed.  If you can dispense with these assumptions and get to the same place (i.e. show how a GBish UG could arise), that would be really wonderful. There would be no objection from generativists. I’ll personally plan a little parade in your honor.  But (you knew this was coming didn’t you?) no GBish UG as end product, then no parade.  No Rosie Ruizing here: you win the prize for running the course not for taking the bus.

Two last points:

First, as BFCB rightly emphasize, aside from the grammatical uniqueness of humans, we also have a second distinctive linguistic quality: our cognitive atoms (words, basic concepts) are entirely unlike those we find in other animals.  The uniqueness of the lexicon thus also requires explanation and is thus more grist for the linguistic version of Darwin’s Problem.  Once again, this difference between our basic concepts and those of our furry, scaly and feathered friends is an empirical conclusion that seems to have more than a wee bit of evidence sitting behind it. For a good accessible review see Spelke’s discussion in "What makes us smart" (here). She notes that there is little evidence that humans differ from other mammals in what she dubs “core knowledge.” We differ in being speakers of natural langauges. This unique capacity, she notes, allows for the emergence of a qualitatively different set of cognitive capacities when added to the core competencies that we share with other mammals.  So, there are two problems to address, grammar is unique and so are the “words”/concepts we deploy. It would be nice to show that these belong together, but there is currently no good story of how this might be so.

Second, it’s taken for granted that all the discussion is being carried on at a level of abstraction that may compromise the whole enterprise. The abstraction is doubly removed from the real evolutionary playing field. First, The speculations are conducted at the level of minds, not brains nor genomes. Genomes build brains and brains have mental properties. Evolution, via tinkering with genes must have resulted in some new feature of brains ( leading to, e.g. some rewiring or the addition of a new kind of circuit), which led to novel mental capacities. The stories I’ve been offering assume that a small cognitive/mental addition (e.g. merge or label) corresponds to a small brain change which corresponds to a small genetic change. This, of course, need not be true. From what I have been told (thanks Randy, David P), we really don’t have many good ideas concerning the brain correlates of our cognitive primitives (this will be the subject of a future post) in any domain, nor, I suspect do we really know how genes grow brains. Indeed, Randy Gallistel believes that neuroscience as currently pursued is heading off in the wrong direction if the aim is to understand how to brainly embody the right cognitive operations.  So, given this, I have been making the (no doubt stupid? heroic?) assumption that simple cognitive circuits correspond to simple brain circuits that correspond to simple genetic changes.  I doubt that this is true, but right now it is the best we can do and is a game that, I believe, everyone is playing. 

To conclude: Arguments are interesting where there are a sufficient number of shared premises.  The premises that make considering Darwin’s Problem interesting for a linguist include a description of the explanadum as roughly having the properties as described by GB or its kissing cousins.  Absent these, there is no debate or even discussion, simply a denial of the relevant facts. There is nothing one can do about climate change deniers (there is no law against denying climate change, nor should there be), and there is nothing one can do about UG deniers. However, there is no interesting debate with deniers of either kind. The sad fact is that some debates will be interesting, some not. It pays to know which are which.  

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[1] For not the first time, Paul Pietroski made these points ahead of me and better. But since I had already written these up I thought I’d post them anyway.  Never too much of a good thing, in my view.

[2] Berwick, Friederici, Chomsky and Bolhuis make this point and emphasize its importance to the logic of the argument.

[3] NS enthusiasts are not alone in this move. It’s a game favored by neuroscientists as well, especially those impressed with connectionism and its attendant associationsim (see Gallistel & King for extensive discussion).

Darwin's Problem

Humans are uniquely linguistically facile. This raises an interesting evolutionary question, an abstract version of which Minimalists have taken very much to heart: How did this linguistic capacity arise in the species? Following Cedric Boeckx, let’s dub this “Darwin’s Problem.” Answers to this problem have two separable parts: (i) an account of how that which made language a cognitive option became mentally available, (ii) an account of how the available option became fixed in the species.

Most give a “miracle theory” account of (i). What I mean is that it is regularly assumed that some kind of adventitious genetic change/mutation occurred that, when added to the cognitive apparatus already there, combined with it to allow for the emergence of a mental faculty with the key features of FL.  The “miracle” means to mark the observation that this change “just happened,” it’s a brute fact. Minimalists try to (abstractly) characterize the nature of this change (what was added), but that there is no attempt to explain why the change occurred. It just did. What’s up for grabs is the nature of the change (adding Merge being the currently favored candidate, though there have been other proposals, (one by yours truly)) and the number of these. Given the logic of the case (short time span etc.), one miracle is acceptable, two maybe barely tolerable, three fougetaboutit! At any rate, a miracle occurred sometime in the last (roughly) 100,000 years in at least one member of the species.  This brings us to (ii).

Once the miracle occurs, it must be fixed in the population, presumably by giving its bearers some selective advantage (this is the Darwin part).  With respect to language there are basically two possible sources for this advantage, which correspond with two classical views about the utility of language; language as vehicle for communication and language as vehicle for thought. Pinker and Bloom are perhaps the most famous advocates of the first conception. Chomsky is a well-known advocate of the second.

There are two main problems with the communication view.

First, it requires double the number of miracles. Note, this follows from two observations: that it takes at least two to communicate and mutations (the required miracle) originate in individuals and spread to populations via the reproductive success of the favored individuals. Thus, as improbable is it is for Merge, say, to pop into an individual ape mind once the chances of it doing so twice in two different (assuming that communication is between at least two individuals) proximate (if not near each other than the capacity to communicate won’t be realized) individuals, is much much more improbable still. Indeed if the events are independent, then it’s the square of the probability of the unique event.

Second, we need a story about why the particular form of communication, a communication system based on Merge like grammars, is so much more advantageous than a simpler system would be.  Here’s what I mean. Consider a simple linear N-V-(N) grammar with a vocabulary of 500 verbs and 1,000 nouns. This can support roughly 500,000,000 different messages. That’s a good number of messages, all without hierarchical recursion.  We know that animal communication doesn’t require recursion. The evolutionary question then  is what communicative advantage does the miracle promote that would be particularly advantageous?

Considerations like these led many to conclude that the main selective advantage of language was its enrichment of thought rather than its communicative efficacy. Here’s Francois Jacob’s take:

…the role of language as a communication system between individuals would have come about secondarily…Its primary function would rather have been, as with earlier evolutionary steps in mammals, the representation of a finer and “richer” reality,” a way of handling more efficiently a greater amount of information. As exemplified throughout the whole animal kingdom, communication can be easily established between individual organisms.  Even among hominids which had to hunt and live in community, most of the information to be shared with others and concerning immediate features of life could be handled by means of rather simple codes.  In contrast, to translate a visual and auditory world so that objects and events can be precisely labeled and recognized weeks or years later requires a much more elaborate coding system. The quality of language that makes it unique does not seem to be so much its role in communicating directives for action as its role in symbolizing, in invoking cognitive images. We mold our “reality” with our words and our sentences in the same way as we mold it with our vision and our hearing.  And the versatility of human language also makes it a unique tool for the development of imagination. It allows infinite combinations of symbols and, therefore, mental creation of possible worlds (58).[1]

Thus, the proposal is that grammatical structures enhance the class of entertainable and easily retrievable of thoughts. It allows for the imagination of alternatives, thereby, one might suppose, enhancing planning and action (as well as making dawdling that much more enjoyable!).  At any rate, were this so, then it is not hard to imagine how a miracle that enabled this would immediately endow its individual bearer with the kinds of advantages that natural selection cares about and how, therefore, this miracle could go forth and multiply via its bearers going forth and multiplying.

Before going on, we should appreciate that all of this is speculative.  As Lewontin has made clear, there is a big, perhaps ultimately insurmountable, step between this and a serious scientifically grounded selective explanation. As he demonstrates in detail (c.f. his "The Evolution of Cognition" in volume 4 of The Invitation to Cognitive Science), it’s extremely hard to move beyond just-so stories and provide empirically justified evolutionary accounts of cognitive capacities.

This said, there are tantalizing hints and what I want to point to one.  I have just reread some fascinating work (from 1999) by Hermer-Vazquez, Spelke and Katsnelson (H-VSK) that bears on these questions. They provide evidence for the kind of scenario that Jacob describes above.  Here’s what they found (from the abstract):

Under many circumstances, children and rats reorient themselves through a process which operates only on information about the shape of the environment... In contrast, human adults relocate themselves more flexibly by conjoining geometric and non-geometric information to specify their position. The present experiments used a dual-task method to investigate the processes that underlie the flexible conjunction of information…Together the experiments suggest that humans’ flexible spatial memory depends on the ability to combine divers information sources rapidly into unitary representations and that this ability, in turn, depends on natural language.

The experiments all involve disorienting children and adults in a rectangular room. The task is to find something in a prescribed corner. Sometimes the indicated corner abuts a wall with a certain color, thereby distinguishing it from the geometrically analogous opposite corner. Adults are able to exploit the additional color information to locate themselves and thus to identify the right corner (i.e. color serves to disambiguate the geometrical information). Prelinguistically capable kids cannot. Nor can rats.  More interesting still, H-VSK found a way of stopping adults from using the color information by having them engage in a language task while reorienting themselves. Presto, the adults start acting like kids and rats.  Importantly, engaging in additional non-linguistic tasks during reorientation does not stop successful identification of the correct corner.  This strongly implicates language use in facilitating spatial orientation.

I hope I have piqued your interest. The experiments are a delight to read (so do so) and the implications for Jacob’s (and Chomsky’s) evolutionary scenario very suggestive. Here we have a case where linguistic facility directly enhances something as basic as spatial orientation, a capacity that it does not take much imagination to suppose would be useful to our hunter-gatherer ancestors and would endow selective advantage in a wide range of plausibly relevant environments.

How exactly does language help?  H-VSK speculate that language constitutes a kind of interlingua allowing diverse information from separately encapsulated cognitive modules to combine into single thoughts.  The capacity to so combine diverse concepts allows for more complex thoughts and thereby allows, in Jacob’s words, for “the representation of a finer and “richer” reality.” In sum, were the Jacob-Chomsky speculation on the right track we might expect to find cognitive enhancement for selectionistically valuable traits, and this seems to be what H-VSK have found. Wow!

Need I say that this is still very speculative?  However, though a first step, it is very interesting and fits well with certain other assumptions out there minimalists are sure to find congenial.

First, standard Minimalist theory proposes a strong asymmetry between the two interfaces.  Rather than syntax being a pairing of sound (AP) and meaning (CI) (the standard view since Aristotle), it is more accurately thought of as a relation between structure and meaning with sound as an add-on (Chomsky has strongly pushed this line of late).  The derivation from lexicon to CI is clean and well designed (e.g. it meets Inclusiveness, Extension and Full Interpretation). The mapping to sound is considerably messier (e.g. does not conform to Inclusiveness). This fits well with the Jacob-Chomsky conception which presumes that the real biological action starts with the generation of complex thoughts that grammar makes available, not spoken outputs, which are a later accretion. 

Second, Generative Syntax endorses the autonomy of syntax thesis (AOS). Though AOS has often been misunderstood to assert that there is no relation between the grammar and meaning, it actually means that the primitives and operations of the grammar are independent of the contents of what they are used to express. In particular, syntactic categories, principles and operations to not reduce to semantic ones. Many have taken this to be a serious defect. However, in the context H-VSK’s results it looks like a great design feature.  Precisely because the syntax is autonomous it is able to combine information from different encapsulated modules. In other words, autonomy is just the flip side of not being modularly restricted.  The intra modular primitives and operations cannot do this, which is what makes it impossible for rats, young kids and linguistically distracted adults from combining different kinds of information (i.e. predicates from different modules). From the present perspective, a more revealing term for the autonomy of syntax might be the inter-modularity of syntax, autonomy being precisely the property we want in a tool required to combine diverse types of thoughts and concepts, ones otherwise confined to specialized cognitively encapsulated modules.

Last, consider hierarchy.  The kind of combination H-VSK’s tasks require is one that allows for diverse kinds of information to work together to produce finer and finer descriptions. In other words, we want the capacity to modify, viz. stack adverbs, specify events, combine nouns and adjectives, use sentences to cut down possibilities (e.g. as  relativization does) etc.  This is the conceptual value added that syntactic hierarchy provides, and it does so in spades. 

In sum, the Jacob-Chomsky “conjecture” when combined with a generative syntax with a minimalist flavor has a suggestive tang: it links what is special (viz. recursive hierarchy) with what is plausibly beneficial (viz. the capacity to entertain new and useful thoughts).

One of the novelties of the Minimalist Program has been the elevation of Darwin’s Problem to prominence along side Plato’s.  Interestingly, it appears that the empirical just-so stories of yore might finally graduate to empirically so-so stories and, one day maybe even to thus-so stories. Wouldn’t that be nice? Can’t blame a person for dreaming. In the meantime, take a look at H-VSK. It’s a great paper.

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[1] From The Possible and the Actual (1982). University of Washington Press; Seattle.