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Science

The Language Seed - A Clue to the Nature of the Human Mind

Hiroki Narita
Assistant Professor, Waseda Institute for Advanced Study

All children are linguistic geniuses. Without conscious effort, they absorb the linguistic data provided by speakers in their environment (be they in Japanese, English, or any other language)., They build up an accurate vocabulary at an astounding speed of tens of words per day, and within just a few years of birth, they uniformly acquire an extremely intricate grammatical knowledge of their mother tongue, whose complexity remains to be fully elucidated by contemporary linguists.

Such a remarkable capacity for language learning seems to be a privilege granted only to human children. Numerous experiments have been conducted (in the past) to try to teach the grammar of natural languages to nonhuman primates, birds, and so on, but such attempts have proved futile. No matter which species the experiments involved and however sophisticated the training techniques, no nonhuman species have been able to learn the grammatical forms of human language. The fact that only human children can speedily and effortlessly acquire this special knowledge without explicit instruction is one of the great mysteries concerning the human species.

It is known that the mature linguistic capacity of human beings exhibits a number of unique features that are not observed in the cognitive mechanisms of other animals. One of the main characteristics is the infinity of our phrase structures. In Japanese, for instance, a simple sentence such as "Taro ga hon o yonda" ["Taro read the book"] can be embedded into another sentence, as in: "Hanako ga (Taro ga hon o yonda) to omotta" ["Hanako thought that (Taro read the book)"). Such a sentence can be further embedded into an even longer sentence ("Taro ga. to shinjiteiru" ["Taro believes that."], "Akemi wa. ka shiranai" ["Akemi doesn't know whether."], ". to no jouhou ga aru" [There is information that."], and so on.) There is, in principle, no limit on the length of sentences that can be generated by recursive embedding (or, no limit on the depth of embedding). This means that there can be no 'longest sentence' in Japanese, and the number of phrase structures that can be produced by Japanese grammar is, in principle, infinite. All other human languages show the same property. Interestingly, infinity of structured expressions is a unique formal property of human language, not found in cognitive systems of any other animals. Many kinds of primates, birds and so on communicate using sounds produced by oral articulatory systems or the equivalent, but they lack any cognitive mechanisms that can support the structural infinity of human language. Building on these observations many have formed the hypothesis that it is this capacity to perform recursive operations such as embedding that fundamentally distinguishes the human species from other living organisms. There is ongoing vigorous debate surrounding this hypothesis among researchers of comparative biology, animal ethology, evolutionary biology, and so on.

Why is it that only human beings can acquire language? And why is it only human language that demonstrates this array of specificity including the infinity of phrase structure? One reasonable hypothesis that addresses these questions is that human beings alone are granted some kind of special apparatus that enables language acquisition, or a kind of 'language seed ', which is inherently built into the human brain in some form. Its development is triggered by the input linguistic data from the surrounding speech community, and matures into the grammatical knowledge of natural languages such as Japanese and English. Its developmental processes are largely internally determined, through which it comes to bear a number of characteristics such as inifinity of phrase structure.

Figure 1 Only human beings are born with a language seed. This seed absorbs the linguistic data from the surrounding speech community, and grows into grammatical knowledge which exhibits features such as the infinity of phrase structure.

The research that addresses the problem of explaining the internal structure and developmental process of the language seed is called generative grammar. Generative grammarians examine theories about the structural characteristics that the language seed must have (called universal grammar or UG). In doing so, they treat the grammars of Japanese, English and so on as different mature states developed from the same seed and examine the uniformity and variation among them. This is analogous to trying to explain the genetic properties of the soybean through a comparative study of the structures of its two different mature forms, the green soybean and the bean sprout, both of which come from the same soybean. Other research methods include monitoring the electrical activities of the brain during linguistic behavior using neuroscientific techniques, observing the language learning process of children to verify the developmental mechanisms of the language seed, and studying the formal characteristics of human language through comparison with other human and nonhuman cognitive systems (such as human visual perception, the grammar of birdsong, and the action grammar of anthropoids.) Generative grammar therefore faces a rich variety of interesting research problems.

Figure 2 Just as one soybean will grow into a green soybean or a bean sprout depending on the environment in which it is planted, the language seed grows into Japanese or English depending on its surrounding linguistic environment.

The language organ which grows from this mysterious language seed is vital for the expression of human thought. There can be no doubt that the system of human thought differs significantly from that of any other animal cognition, but the uniqueness of human thought may well reside in the lithe branches and rich foliage that grow from the language seed. These may be said to spread over the "soil" of sensory and cognitive mechanisms we likely share with other animals. Since the language seed (that is, the language faculty) is a biological endowment specific to humans, it would be an interesting research endeavor to investigate the extent to which its existence may explain the uniqueness of human thought. Rather than just being a tool for referring to things that already exist in our sensory world, language itself may be the thread that weaves together human beings' unique intellectual and cognitive worlds.

When Descartes, the father of modern philosophy, attempted to eliminate supernatural beings such as spirits and God's will, taken for granted in the theology of the Middle Ages, from the explanatory theories of physical science, he was pushing forward his major idea that the totality of physical events in the natural world, whether they involve terrestrial matter or planetary motion, can fully be explained by simple laws of physics such as the law of conservation of momentum and the law of inertia. This was a revolutionary idea that later triggered a number of huge shifts in physical science initiated by researchers like Newton. Descartes initially intended to develop his mechanical philosophy as an ultimate theory to explain all events in the universe, but what stood firmly in the way of his ambition was the infinite creativity shown by human beings' normal use of language. Nearly all the actions of other animals could, in Descartes' eyes, be explained by relatively simple schemata of physical stimulus and response (such as being hit and crying out in response). Only the unbounded speech acts that human beings can perform spontaneously without any external trigger thoroughly resisted causal explanations appealing to any such physical factors. Faced with the difficulty of explaining humans' creative use of language, he was forced to conclude that there must exist a world of events consisting of a second entity, i.e., thought (called 'res cogitans'), that did not rely on the principle of causality in the physical world and was, therefore, beyond the scope of explanation by physical science. This was the origin of the traditional mind-body problem. Since then, the science of the world of matter (physics) has undergone numerous revolutions from classical dynamics to the theory of relativity and quantum theory, resulting in countless changes and extensions of our notions of matter. Still, we have not known how to overcome the huge divide between the world of matter and the world of the mind. Of course, we know that the two meet in some form in the brain. But even with monitoring devices of the most advanced technologies in modern neuroscience (albeit far more precise than in Descartes' day), we cannot find anything in the brain more than some transitional distribution of complex electrical activities. We have no idea how mental events such as consciousness, sensation, thought, etc. are generated inside the black box of the brain.

However, now we may be able to say that we have a clue as to how to approach the mystery concerning the nature of this divide---that is, the language seed. It is, on the one hand, a complex of neural wiring generated by human biology, which means it must be in every respect a physical entity. On the other hand, it absorbs linguistic experiences from the sensory organs and extends its branches and foliage that greatly broaden the cognitive world of humans, growing into a mechanism that serves as the basis of the spontaneous and creative use of language such as that Descartes observed with puzzlement. In this sense, it also lies in the foundation of human thought. The tree that grows from the language seed is, to wit, a bridge that connects the world of matter with the world of the mind.

Through inquiry into the internal structure and developmental process of the language seed, we may eventually unravel parts of the mechanism that underlies the real nature of the human mind. Further, we may, ultimately, gain some insight into to the mystery of the formation of a dualistic world of matter and the mind. Indeed, it may be the study of human language that holds the key to future breakthroughs that cut across the boundaries of fields such as physics, neuroscience, cognitive science, psychology, and philosophy---a bold prospect that long thrilled generative grammarians like me.

Figure 3 Could the tree that grows from the language seed be a bridge across the divide between the world of matter and the world of the mind?

Hiroki Narita
Assistant Professor, Waseda Institute for Advanced Study

[Profile]
Professor Narita graduated the College of Liberal Arts, International Christian University in 2005 and completed the master's program at the Graduate School of Foreign Studies, Sophia University in 2007. He then obtained a PhD in linguistics from the Graduate School of Arts and Sciences, Harvard University in 2011 before taking up his current position at Waseda Institute for Advanced Study in April that year. His areas of specialization are cognitive science and theoretical linguistics.

[Main publications]
・"Phase cycles in service of projection-free syntax", Phases: Developing the framework , Mouton de Gruyter
・"Gengo o meguru nani to naze - Seisei bunpou no shiten kara" [" 'What' and 'why' questions concerning language: From the perspective of generative grammar "] (2011, co-authored with Naoki Fukui), Nihongogaku Vol 30, No 13: 24 - 33
・"A naturalist reconstruction of minimalist and evolutionary biolinguistics" (co-authored with Koji Fujita), Biolinguistics Vol 4, No 4
・"The tension between explanatory and biological adequacy. A review of Naoki Fukui's Theoretical Comparative Syntax", Lingua Vol 120
・"Internalism as methodology" (co-authored with Terje Lohndal), Biolinguistics Vol 3, No 4
・"Full Interpretation of Optimal Labeling", Biolinguistics Vol 3, No 2-3
・"How Syntax Naturalizes Semantics. A review of Juan Uriagereka's Syntactic Anchors: On Semantic Structuring", Lingua Vol 119, Issue 11

[Websites]
・Personal website: http://hirokinarita.org
・naturally mind/brain (Podcast): http://hirokinarita.org/podcasting/naturally-mind-brain