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An electrophysiological look at
language: Knowing what happens when, to what degree, and in what context when
something is happening almost all the time |
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Marta Kutas University of California, San Diego Acknowledging that language processing is a brain function requires
some appreciation of how brains are built (anatomical and functional
organization) and how they work – as far as I can tell generally speaking, as
it seems that from the brain’s point of view, language is just another
input/output which it needs to understand relative its current goals. The
brain is neither a linguist nor a psycholinguist, but it can provide data
relevant to both – just which input streams belong to the language and which
do not, and why – and when and how, and how to put them together to
understand, communicate, persuade, etc. The how and the when -- i.e., the
mechanisms and dynamics of language processing can be investigated by probing
or tasking the brain in ways that lead it to reveal its mysteries via small
but systematic changes in electrochemical current flow that penetrates the
scalp, can be picked up by electrodes, amplified, stored for safe-keeping,
and analyzed for reliable correlations with stimulus, task, response, and
individual variables. I will start with a brief overview of event related
brain potentials (ERPs) as dependent measures in studies of language –
neurophysiology, methods, analyses, and inferences they allow. Next will come
a selective and cursory catalogue of ERP components (especially N400,
P3/P600, MMN, LRP) that have proven useful in language research, followed by
a few more detailed examples of how ERPs have been used to study language
processing – studies that reveal that language is predictive, incremental
(albeit not always fully), and intricately intertwined with semantic memory,
engages both hemispheres (not always in the same way), that resources (hard
constraints in timing and memory) may define competence possibilities not
just performance, that it matters when you look at a dynamic system, that the
neurobiology of language includes more than just where in the brain things
happen, and that though language is very special from the brain’s point of
view it’s just another set of noisy, incomplete, ambiguous set of
regularities that it needs to understand as appealing, aversive, requiring of
some reaction/response or not. |