Our literacy organization discussed how research completed by Dr. Joy Hirsch at the Memorial Sloan-Kettering Cancer Center and Cornell University Medical College indicated that infants learn languages differently compared to adolescents and young adults. Her research sparked a lot of interest with The Talking Page Literacy Organization and on LINGUIST List, an online forum for the international linguistics community. The forum discussed the topic in issue 8.1476 released on Sunday, October 12, 1997.
Language Locations In the Brain
Editor for this issue: Martin Jacobsen
Recently I posted a request on this list (and several others) for reactions to the 7/10/97 article by Kim and Hirsch in Nature reporting functional MRI research showing a difference between bilinguals acquiring both languages as infants or young children, and bilinguals acquiring their second language as adults. A Memorial Sloan-Kettering news release had the following quotation attributed to Dr. Joy Hirsch: "A second language acquired during the teenage years, which is late in developmental life, is represented in the brain in a separate location from the native language. But when both languages are learned at the same time early in life, they are represented in areas that have a considerable amount of overlap." ("Bilinguals Devote Distinct Areas of Brain to Native and Second Languages," MSKCC: Press Releases, online.) The NY Times for 7/15/97 ran a story titled "When an Adult Adds a Language, It's One Brain, Two Systems"; the Wall Street Journal's story on 7/10/97 had two headlines -- "How Language Is Stored in Brain Depends on Age" and "Where Languages Are Stored in Brain Depends on Your Age." I immediately began receiving phone calls and mail with questions about this research. I am not a neuroscientist and did not feel competent to answer the questions with even minimal accuracy; I am very unwilling to add to the usual confusion created by such media reports. I wrote the authors requesting clarification, and got no response; I did an online search and found nothing that I felt I could trust; I then asked for help from the lists. (Depending on the precise wording, a search on "language locations in the brain in bilinguals/multilinguals" on Neuroscience Web Search gets roughly 3000 hits, through which I have been doggedly working my way.) My sincere thanks to all who responded.
The majority of responses were from individuals expressing interest and asking that I share whatever information came my way. A number of responses can be summarized as "This research is nothing new, nor is it especially significant." (Medical professionals responding, who rely on information of this kind in order to do neurosurgery without catastrophic effects on language capacity in patients, disagreed with that judgment.) A number of bilingual or monolingual responders wrote with accounts of personal experiences that were extremely useful and interesting. Excerpts from responses that strike me as of general interest follow; they are taken from very lengthy postings and should be understood *only* as excerpts.
From Joe Hilferty: "Kim et al. ...just investigated neural activation in Wernicke's and Broca's areas, because the two sites are well known from the long tradition of aphasia studies. Their findings do not mean, however, that language is only processed in these areas of the brain." References suggested: ** Bates 1994, "Modularity, Domain Specificity and the Development of Language," Discussions in Neuroscience 10:1-2;136-149. **Maratsos and Matheny 1994, "Language Specificity and Elasticity," Annual Review of Psychology 45: 487-516.
From Brian MacWhinney: "I have argued that early bilinguals project the input linguistic data to a single space, because that space is not yet saturated by weights on synaptic connections and the two systems can be learned together in a computationally reasonable sense without worrying about catastrophic interference. In adult L2 learning, the optimal area for an ability has already been occupied land new learning must either use the old territory in a new way or else coopt adjacent 'new' territory. ... A lot of what is at issue here is exactly what the role of Broca's area in language processing might be. ... I would like to think of Broca's as controlling high level sequential planning for language and related abilities."
From Liz Bates: "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! ...
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."
From Lise Menn: "It's not an unreasonable result given earlier indications that late bilinguals had a more bilateral representation of language than early bilinguals (using one-hand motor tasks as indicators of hemispheric involvement), and given Damasio's claims that meaning of words with concrete referents is represented in a way that is linked to our sensory experience of those referents (hence, language independent).
Additional references that were suggested by a number of list members:
Hull, Philip, 1990. UC Berkeley Psych. Dept. dissertation. "Bilingualism: Two languages, two personalities."
Bain, Bruce, 1996. Pathways to the peak of Mount Piaget and Vygotsky: Speaking and cognizing monolingually and bilingually. Rome: Bulzoni Editore.
Mollica, Anthony and Marcel Danesi, 1995. "The Foray into the Neurosciences: Have We Learned Anything Useful Yet?" Mosaic 2:4;12-20.
Danesi, Marcel, 1994. "The Neuroscientific Perspective in Second Language Acquisition Research: A Critical Synopsis. International Review of Applied Linguistics 32:3;201-228.
In addition to my desire not to answer questions about this matter stupidly and/or ignorantly, I was interested in this research because I have been investigating the perception in many bilinguals/multilinguals that they are "a different person" when they use different languages. (I won't bore you with an account of this; I mention it just to provide context.) I became interested in this when Diana Cook sent me "The Bilingual Self: Duet in Two Voices," by RoseMarie Perez Foster, "Cultural and Conceptual Dissonance in Theoretical Practice," by Carla Massey (a response to the previous item), and "The Bilingual Self--Thoughts from a Scientific Positivist or Pragmatic Psychoanalyst, by Perez Foster (a reply to Massey). All are from Psychoanalysitc Dialogues 6:1, 1996, pp. 99 ff. (Sample from Perez Foster's article, page 101: "Thus the bilingual person presents a packaging puzzle, as it were, in which two language-bounded experiential systems are housed in the confines of a single mind." And from page 100, "Bilinguals may possess different experiences of the self, which are organized around their respective languages.") It would have been extremely interesting if the individuals in my database who report this "different person" perception and those who do not correlated in some fashion with the "different storage locations in the brain" research; they do not.
I found especially helpful, and thorough, and informative, the article "Brain evolution and neurolinguistic preconditions," by Wendy K. Wilkins and Jennie Wakefield, in Behavioral and Brain Sciences (1995) 18:161-226, together with the many pages of commentary on their target article in the same and subsequent issues and their responses to those comments. Wilkins and Wakefield (page 170) propose that Broca's area is "a processing module whose inherent specialization is the hierarchical structuring of information in a format consistent with a temporally ordered linear sequence reflective of that structure."