Liz Bates' response from Italy

[Suzanne E Kemmer]

Sorry for reposting a msg that did in fact get posted earlier
(despite error msgs to sender). But the repost was useful in
provoking the following response from Liz Bates.
--Suzanne

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>>From bates at kant.irmkant.rm.cnr.it Mon Oct  6 05:45 CDT 1997
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From: bates at kant.irmkant.rm.cnr.it
Date: Mon, 6 Oct 1997 12:38:20 GMT
To: kemmer at RUF.RICE.EDU
Subject: Re:  forwarded re: lg. localization in brain

I'm on sabbatical in Rome, on a steam-driven email system that
precludes easy distribution -- but feel free to forward this to
Funknet if you think it would be useful....

I believe that the article in Nature on differential localization
for Language 1 and Language 2 represents the kind of gross
over-interpretation of neural imaging data that has become all
too common in the last few years.  Let's be clear about exactly
what this paper (like many others before it -- this is not the
first paper on neural imaging in bilinguals) has really shown:
(1) patterns of activation associated with covert speech in L1 and
L2 are largely very similar, but (2) there are some reliable differences
in the center and extent of activation in the Broca region.  None of
this has anything necessarily to do with STORAGE of L1 vs. L2!  Presumably
(although very very little subject information was provided) these
are people who are less fluent in their second language.  Hence, in
essence, covert speech in L2 is a somewhat different task, with
somewhat different demands.  In fact, I myself fit their description
of these biliguals fairly well, and I can assure you that I am
less articulate and fluent in Italian, even though I have spoken it
for 31 years (including a semester-long course taught in Italian).
Now: if I pick up a pin, and then pick up a pen, I will necessarily
configure my hand slightly differently for these two tasks.  Does
that mean that I have a "pin processor" that is distinct from
and located separately from my "pen processor"?  Or is this simply
the dynamic (and transient) result of somewhat different task
demands?  In the case of the hand, we assume the latter.  In the
case of brain activation studies, we typically assume the former.
Neither one is justified, in and of itself, by the data we are
discussing right now.

Aside from this serious problem of confusing patterns of slightly
non-overlapping activity with separate modules, separate mechanisms,
separate storage of knowledge, there are other problems here as well.
For example, the assumption that Broca's area mediates grammar while
Wernicke's area mediates semantics is HIGHLY controversial, and
in my view, probably dead wrong.  Both Broca's and Wernicke's aphasics
have severe grammatical problems, but they take a somewhat different
form (e.g. omission in the former case, substitution in the latter).
And those studies that have tried to find a 'grammar area' through
neural imaging of normals have generally found EITHER that grammar
and lexical semantics activate the same areas, OR they have found
differences that vary markedly from study to study, and even from
one individual patient to another -- consistent with a "task demand"
interpretation of the data.  Another problem lies in the assumption
that any area which mediates language is a "language area."  In fact,
a number of recent neural imaging studies have shown that EVERY SINGLE
PIECE of the Broca's area complex (and, by the way, even the boundaries
of Broca's area of controversial, varying from study to study) is
activated by one or more covert motor tasks involving non-linguistic
motor activities, of the hands or tongue or both.  So it is possible
that ALL we are seeing in this study in Nature is an effect in which
bilinguals set their mouths a little differently (covertly, of course)
while speaking their second language -- possibly reflecting greater
difficulty in L2 in this case.

I hope this is useful. -liz bates