Last week marked the end of my Second Language Acquisition class with Dr. John Schumann over at UCLA. The class was amazingly good. Dr. Schumann is an old-school applied linguist who, halfway through his career, decided that studying applied linguistics from a cognitive psychology background was futile without more practical grounding in how the brain actually works. So, he decided to pick up neuroanatomy, in his spare time. He now does research in second language acquisition, but from a highly neuroanatomy slant. The majority of the class, therefore, was spent contrasting the acquisition of language from a psycholinguistic perspective to acquisition of language from a neurolinguistic perspective.
Now, The continuum of science in academia has always been a fight between “hard” and “soft” sciences. On the soft side, we have the humanities and social science. On the hard side we have chemistry and physics (aside: is String Theory a hard or soft science? On one hand it tries to be theoretically robust, on the other hand, it hasn’t been verifiable/falsifiable, so it cannot be grounded in reality). Because hard sciences are usually taken more seriously, I would say that most sciences that are on the fringe between hard and soft (e.g. psychology, linguistics, and specifically second language acquisition) usually try to establish themselves as “hard” rather than “soft”. Thus sprung psychological behaviorism, and psycholinguistics out of their mother fields. Second Language Acquisition (especially in the context of applied rather than theoretical linguistics), attempting to align itself with the “hard” side of things, has also cozied up to behaviorism and cognitive psychology in an attempt to “prove” and itself to itself and the rest of the world.
The problem with this, Schumann says, is that no matter how far researchers follow cognitive psychology, it won’t ever lead Second Language Acquisition into being a “hard science”. What is missing, and what cognitive psych can’t ever give, is indexicalization of the brain. That is, saying “this area processes grammar”, “that area processes phonemic distinction”. (Wernicke’s area and Broca’s area are vast oversimplifications of what really goes on, so don’t get me started on that. But I digress). The problem with cognitive psychology from a “hard science” perspective is that it creates these cognitive models, these black boxes (it calls them “cognition”, “motivation”, and other names), but they are just models that approximate observed behavior in humans–and, like theoretical linguistics, it’s easier to get caught up in the pursuit of a model than finding empirical proof of the physical real-world counterparts to the models (and that, right there, was my major bugaboo with theoretical linguistics). Where, Schumann asks, is the localized referent for “mind”? Where in the brain is the “cognitive” center? And do we dare even begin to ask about “consciousness”?
This is not to say that no theoretical models have specific physical referents in the brain. It is very established that the temporal lobe processes vision and simple motivation. But vision (and even more so, language) is spread through a bunch of places in the brain. It seems like the system is too emergent for us to pinpoint specific areas to which to tie down our black boxes.
What is cognition? Cognitivists say it is “computation on representation”. Neurolinguists, by contrast, say it’s not such a unified thing–that what we call cognition is an amalgam of specialized functions (perception, memory, fear analysis, reasoning, …). And so, with no unified referrent for a theoretical model, “cognition” (and second language acquisition that’s motivated by cognitivist theory) can never become a truly hard science.
Structurally, it’s the difference between the brain being a turing machine, and being just turing-compatible.