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.
