Is There a Language-Area of the Brain?—And Moro’s Experiments about Real and “Fake” Italian

Oct 22, 2015 by

Russian neurolinguist and experimental psychologist Tatiana Chernigovskaya has recently given a public lecture “How the internet changed our brain”. (Thanks to Inna Louneva for drawing my attention to this lecture.) A transcript of this lecture (in Russian) is posted on the Snob.ru website. Of course, the part that particularly caught my attention is where she talks about language and whether there are language-specific parts of the brain. She said (translation mine):

“We know, of course, that there are functional blocks in the brain, that there is some sort of localization of functions. And we think, like fools, that if we are performing a language-related task, then the brain areas that are occupied by speech would be activated in the brain. But no, they wouldn’t be. That is, they would be functioning, but other areas of the brain would be taking part in that as well. Attention and memory will be working. If the task is visual, then the visual zones would also be working, and if it is auditory, then the auditory zone will be working. Associative processes would also always be working. In other words, in performing some task it is not a specific area in the brain that gets activated but the whole brain is always working. That is, zones responsible for a particular task as if exist, but at the same time they sort of don’t exist.”

The reason I cite a long paragraph like this is to point out several problems. First of all, Chernigovskaya does not distinguish language and speech—a vital distinction first proposed by Ferdinand de Saussure. Moreover, as the example of sign languages shows, languages can exist without (auditory) speech. Presumably, the same language areas of the brain, such as the Broca’s area, are functioning during performance of sign language tasks as well, although I am not aware of any studies that show that. (If any readers know of such studies, please use the Disqus section below to share the info.)

But there is a bigger problem in Chernigovskaya’s argument. That we cannot isolate one particular language area by examining brain function during a performance of a language-related task does not mean that such area doesn’t exist. Simply put, we are permanent multi-taskers: in addition to whatever task we focus consciously, our brain controls other life-supporting and cognitive tasks. No matter what activity we engage in, we continue to breathe, blink, swallow, process the sensory information from our environment. Moreover, experimental subjects whose brain function is being examined as they engage in a language-related task may be thinking of a myriad of other things: “Did I put enough coins in the meter?”, “What should I have for lunch today?”, or even “That red-haired receptions is so cute!”

MoroBecause it is hard to isolate brain activity due to a linguistic task, many early neurolinguistic studies got stalled. But a series of such studies conducted under the leadership of Italian linguist Andrea Moro have solved this problem. These studies and their conclusions are described in Moro’s fascinating and accessibly-written book, The Boundaries of Babel (available in both English and Italian). This book is a great read and a must for anyone interested in the topic, so what follows is just a “Cliff’s Notes”-like summary of Moro’s experimental findings.

In order to figure what the brain does when it “does language”, Moro and his team designed experiments where brain activity during a performance of a linguistic task could be compared to brain activity during a performance of a very similar, yet crucially not-quite-linguistic task. What could such “not-quite-linguistic task” be? In Moro’s experiments, this task involved learning—and then accessing sentences in—a non-existing and even impossible not-quite language (hence, the subtitle of Moro’s book “The Brain and the Enigma of Impossible Languages”). In order to construct such “impossible language”, Moro used the building blocks (i.e. words) of a real language (such as Italian) but grammatical rules that are not only not part of the language in question but are not found in any human language. According to the theory of Universal Grammar (UG), natural human languages, as varied as they can be, are subject to universal constraints (aka Principles) which limit the range of possible languages. One such universal constraint, known as the Structure Dependence Principle, says that grammatical rules in all languages make use of structural notions rather than just linear order.

To illustrate with a specific example, consider how negative sentences in English relate to affirmative ones. The answer is by adding the negative marker “not”—but adding it where? If we take a short sentence such as James Bond can fly and its negative counterpart James Bond cannot fly, the negation appears to be inserted after the third word; alternatively, one could hypothesize that it is inserted after the modal verb (here: can). The first, linear-order-based hypothesis may seem absurd to you, exactly because we don’t encounter such rules in English or any other language. A quick examination of longer sentences, such as The clever spy can fly and The clever spy cannot fly, shows that the structure-based rather than the linear-order-based hypothesis is the correct one for the English negation rule. (If we go by linear order, in these sentences the negation is inserted after the fourth rather than third word.)

But nothing prevents from constructing an artificial language, a “fake English” (or in Moro’s experiments, “fake Italian”) which has exactly the linear-order-based negation rule that says that the negation marker must be inserted after the third word of the sentence, no matter what that word happens to be structurally. (Presumably, such a “fake English” would either not allow one- or two-word sentences or would have a supplemental negation rule that specifies how such short sentences could be negated.) Another rule of this “fake language” might say that a yes/no question is formed by reordering the words in reverse order so that Fly can Bond James is the question from the first sentence above, and Fly can spy clever the questions—you guessed it, whether the clever spy can fly.

Having constructed a small sample of “fake English”, we can compare brain function in people performing linguistic tasks with real English versus brain function in those who do seemingly the same tasks with “fake English”. This is exactly the idea of Moro’s experiments, only his team used real and “fake” Italian (this experiment was repeated with real and “fake” Japanese, but in what follows, I focus on the Italian version). For the experiment, native speakers of German who didn’t speak any Italian were invited to learn a new language. For starters, they were taught a small selection of Italian words. Then some of the subjects were exposed to sentences in Italian, from which they could extrapolate grammatical rules such as the placement of the verb in subordinate clauses, etc. (Note that all the Italian rules selected for the experiment were different from corresponding structures in the subjects’ native language, German.) Other subjects were exposed to “sentences” in “fake Italian” that exhibited non-UG-compatible patterns. After the learning portion of the experiment, subjects were placed into an fMRI machine so that their brain functioning could be examined and were tested as to how well they had learned their new language, either a real or a “fake” Italian. The task was to judge strings as either grammatical or ungrammatical in their “language”.

Broca’s-area-actually-consists-of-two-distinct-subunitsThe experiment supported the UG hypothesis, namely that not any system that operates with words, counts as a language in a strict sense. The results showed that despite the surface similarity between what the two groups of subjects did, what their brain did in both cases is radically different. One finding is that subjects were faster at providing judgments for the real Italian sentences than for the “fake Italian” ones, so it appears that UG-compatible (i.e. Structure-Dependent) rules were easer for subjects to apply than non-UG-compatible (i.e. Linear-Order-Based) rules. The researchers also found that subjects got better the more exposure they had to the real Italian in the learning phase of the experiment, but more extensive exposure to the “fake Italian” did not make much difference in subjects’ performance in the judgment task. Hence, it appears that UG-compatible rules are easier to learn than non-UG-compatible ones. Finally, the examination of the fMRI data revealed differences in brain functioning: in the real Italian experiment, the area that was most activated throughout the task was the Broca’s area, but in the “fake Italian” version, the Broca’s area, although initially activated, quickly delegated the work to some other area. Thus, in addition to providing strong support for the theory of Universal Grammar, this experiment also shows that there is such a thing as “brain area for language”, contrary to Chernigovskaya’s argument.

 

 

 


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