Reheated Chomsky

Chomsky’s theory of Universal Grammar  has faced near-constant criticism since the 1950s, and recent criticism has been very strong indeed, but Chomksy-ist theory (if not Universal Grammar exactly) remains the primary force in modern psychology and lingustics. How is this?

Chomsky originally proposed that there are underlying principles of grammar consistent across all languages, and that these principles stem from the human brain’s biology (originally, Chomsky proposed we had a ‘Language Aquisition Device’ physically in the brain somewhere). One need only learn the vocabulary and ‘parameters’ of a particular language and your brain will compute the rest, fitting it together using this universal grammar. In September’s edition of the Scientific American, Ibbotson and Tomasello claim that Chomsky’s theory has been not meeting empirical evidence for some time now. Many languages don’t appear to fit the grammar rules Chomsky developed, most recently demonstrated in the Piraha’s apparent lack of recursion (the ability to embed sub-clauses within a sentence, forever, e.g. “She said that you said that I said that they said…”). The promised biological device responsible for allowing us to pick up language has also failed to turn up.

Whether or not these propositions are crucial to Universal Grammar, or if the theory can adapt around them, it must be more than a little embarrasing to be so refuted. One might imagine it would prompt serious reflection amongst cognitive scientists of all types and fields, given that this is the theory many credit (over-credit, perhaps) with inaugurating the ‘cognitive revolution’. Then again, perhaps that’s precisely why they might not want to look too deeply into why Universal Grammar isn’t working.

After listing the many faults of Universal Grammar, Ibbotson and Tomasello instead propose ‘Usage-Based Grammar’. Rather than specific language aptitude, humans have general purpose skills that can be used to learn and use language, employing behaviourist principles of learning through trial and error. And rather than a uniquely human language acquisition device, we have a uniquely human understanding of intention.

Perhaps if one is already signed up to the underlying principles of orthodox psychology, this alternative theory would look like heresy; that’s the only explanation I can think of for why such a critical article ends with a such a pulled punch. Ibbotson and Tomasello’s alternative theory does not challenge, but in fact shares, the real underpinning ideas of Universal Grammar, which are the underpinnings of modern cognitive science. Usage-Based Grammar therefore shares many of the same flaws the authors level at Universal Grammar.

Take for instance the absurd idea that to understand, or to have communicative intentions is something unique to humans. Presumably, the evidence the authors would provide for this claim is the same Tomasello has provided in other instances when asserting that humans have unique communicative intentions: that humans can use manual pointing, but apes cannot (see Tomasello 1996, 2006; Moll and Tomasello, 2007). His claim has been falsified by a large collection of evidence demonstrating apes are capable of pointing in much the same circumstances as humans (e.g. Leavens, Racine and Hopkins, 2009; Leavens, 2012, 2014). It is increasingly clear that apes raised in relatively enriched captive circumstances do not show the kinds of deficits in pointing or pointing comprehension that sometimes characterize animals raised in impoverished cages (Leavens et al., 2015; Lyn, Russell, & Hopkins, 2010; Russell, Lyn, Schaeffer, & Hopkins, 2011). Thus, Tomasello and his colleagues have repeatedly confused an effect of impoverished rearing history with a species difference (Bard & Leavens, 2014).

Of course, mere evidence of apes pointing wouldn’t falsify a claim that apes can’t have communicative intent, because nothing can falsify a claim like that. Intention, as conceptualised under cognitive psychology, is invisible. A claim that humans have unique intentions shared by no other species is completely unfalsifiable, which funnily enough is a criticism Ibbotson and Tomasello repeatedly make of Universal Grammar.

This is not me trying to make an idle technical correction.  This claim of uniquely human intentional understanding demonstrates that both theories share the same flaw: a commitment to nativist theory, that postulates unfalsifiable mechanisms within an invisible mind. Both theories subscribe to the cognitivist idea that the environment doesn’t hold enough meaning for us to experience this rich world and behave as we do, and so must resort to using cognition to ‘fill in the gaps’, imposing meaning upon a meaningless world. For Chomsky, that occurs via a Language Acquisition Device; for Ibbotson and Tomasello, that occurs via general cognitive skills, and innate human powers of intention (apparently this is indirectly nativist enough to allow Tomasello to claim the mantle of some kind of anti-nativist). Both of them ignore the material information provided by communicative partners across their exchange.

For instance, conversation analytic studies demonstrate that our interactions’ sophisticated organisation allows individuals to embody their intent unambiguously (Mandelbaum & Pomerantz, 2005), and Mutlu, Yamaoka, Kanda, Ishiguro, and Hagita (2009) found that people interacting with robots ‘leaked’ their intent with emergent behavioural cues. This embodied account of intentionality and communication deals with information actually available for scientific investigation, rather than speculation regarding species-specific intention-reading mechanisms of the mind.

Chomsky’s theory won’t be brought down by  mere technical corrections on a fundamentally shared cognitivist theory. What is being touted as an alternative by Ibbotson and Tomasello is reheated Chomsky: a last-gasp attempt to contain the rapidly accumulating evidence within an over-stretched nativist theory.

funny-chimpanzee-thinking-in-future-header

This post was developed with David A. Leavens, whose feedback and additions were enormously valuable.

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