Chomsky was right, researchers find: We do have a 'grammar' in our head

December 7, 2015
Credit: Paul Brennan/public domain

A team of neuroscientists has found new support for MIT linguist Noam Chomsky's decades-old theory that we possess an "internal grammar" that allows us to comprehend even nonsensical phrases.

"One of the foundational elements of Chomsky's work is that we have a grammar in our head, which underlies our processing of language," explains David Poeppel, the study's senior researcher and a professor in New York University's Department of Psychology. "Our neurophysiological findings support this theory: we make sense of strings of because our brains combine words into constituents in a hierarchical manner—a process that reflects an 'internal grammar' mechanism."

The research, which appears in the latest issue of the journal Nature Neuroscience, builds on Chomsky's 1957 work, Syntactic Structures (1957). It posited that we can recognize a phrase such as "Colorless green ideas sleep furiously" as both nonsensical and grammatically correct because we have an abstract knowledge base that allows us to make such distinctions even though the statistical relations between words are non-existent.

Neuroscientists and psychologists predominantly reject this viewpoint, contending that our comprehension does not result from an internal grammar; rather, it is based on both statistical calculations between words and sound cues to structure. That is, we know from experience how sentences should be properly constructed—a reservoir of information we employ upon hearing words and phrases. Many linguists, in contrast, argue that hierarchical structure building is a central feature of language processing.

In an effort to illuminate this debate, the researchers explored whether and how linguistic units are represented in the brain during speech comprehension.

To do so, Poeppel, who is also director of the Max Planck Institute for Empirical Aesthetics in Frankfurt, and his colleagues conducted a series of experiments using magnetoencephalography (MEG), which allows measurements of the tiny magnetic fields generated by brain activity, and electrocorticography (ECoG), a clinical technique used to measure brain activity in patients being monitored for neurosurgery.

The study's subjects listened to sentences in both English and Mandarin Chinese in which the hierarchical structure between words, phrases, and sentences was dissociated from intonational speech cues—the rise and fall of the voice—as well as statistical word cues. The sentences were presented in an isochronous fashion—identical timing between words—and participants listened to both predictable sentences (e.g., "New York never sleeps," "Coffee keeps me awake"), grammatically correct, but less predictable sentences (e.g., "Pink toys hurt girls"), or word lists ("eggs jelly pink awake") and various other manipulated sequences.

The design allowed the researchers to isolate how the brain concurrently tracks different levels of linguistic abstraction—sequences of words ("furiously green sleep colorless"), phrases ("sleep furiously" "green ideas"), or sentences ("Colorless green ideas sleep furiously")—while removing intonational speech cues and statistical word information, which many say are necessary in building sentences.

Their results showed that the subjects' brains distinctly tracked three components of the phrases they heard, reflecting a hierarchy in our neural processing of linguistic structures: words, phrases, and then sentences—at the same time.

"Because we went to great lengths to design experimental conditions that control for statistical or sound cue contributions to processing, our findings show that we must use the grammar in our head," explains Poeppel. "Our brains lock onto every word before working to comprehend phrases and . The dynamics reveal that we undergo a grammar-based construction in the processing of language."

This is a controversial conclusion from the perspective of current research, the researchers note, because the notion of abstract, hierarchical, grammar-based structure building is rather unpopular.

Explore further: Sex of speaker affects listener language processing

More information: Cortical tracking of hierarchical linguistic structures in connected speech, Nature Neuroscience, DOI: 10.1038/nn.4186

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6 comments

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BendBob
1 / 5 (1) Dec 07, 2015
Has anyone else noted that many speakers are using "questions" embedded in statements?

I hear this on media news programming and PBS programming. I hear it in the general public where I live.

Has this become acceptable speech now?
jwilcos
4 / 5 (4) Dec 07, 2015
This is writeup is very poor. I can only assume that the study this is describing is not this stupid.

- It is a trivial fact that people have 'grammar in their head'. If you are an adult fluent speaker of a language, you know the grammar. What Chomsky claimed is that this cannot be learned, and babies are born with an innate grammar that covers all human languages. Nobody has been able to find what this universal grammar is, in 50 years of research. Nobody can tell you what the 'principles and parameters' are, they can only claim that they exist and magically solve everything. Hence this is not accepted by most sensible people (except those who have had the misfortune of being trained in traditional linguistics).

- You cannot eliminate statistical cues. Cues occur at many levels, not just a individual and specific word level. Cue is not just that 'pink' and 'girl' are associated or one is likely to follow one another. They also operate at the level of categories (nouns go here).
Torbjorn_Larsson_OM
4 / 5 (2) Dec 07, 2015
"Chomsky was right, researchers find ... This is a controversial conclusion".

TL;DR: TL;DR.
Lex Talonis
1 / 5 (1) Dec 08, 2015
Of course Chomsky is right. I taught him this.
zaxxon451
2 / 5 (1) Dec 08, 2015
Chomsky is right about a lot of things.
jibal
not rated yet Dec 13, 2015
jwilcos, if you want to sway people rather than come across as an ignorant crank, it's best to tone down your emotion, your hostility to "traditional linguistics", and your reliance on what you think is "sensible" ... science has a way of shattering such notions. The article could have made mention of "innate", but it's not stupid ... you seem not to understand the research or how it differs from the common view of neuroscientists and psychologists. Yes, of course we all know a grammar, but that's "knowledge of", not "knowledge how". Brains processing language do not do so by checking the incoming signals in real time against a knowledge base of our native language ... both the Chomskian and standard psychological view agree on that.

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