Language and Cognition Catherine L Harris, Boston University, Massachusetts, USA
Total Page:16
File Type:pdf, Size:1020Kb
Galley: Article - 00559 Level 1 Language and Cognition Catherine L Harris, Boston University, Massachusetts, USA CONTENTS Introduction Cognitive linguistics Concepts of cognition and language The Cognitive neuroscience movement Connectionism Conclusion Cognitive scientists have long debated whether lan- The second way ofconceptualizing human cog- 0559.003 guage and cognition are separate mental faculties, nition emphasizes the differences between lan- or whether language emerges from general cogni- guage and other abilities. A key idea is that many tive abilities. distinct domains ofcognition exist and must be learned separately, using different mental mechan- INTRODUCTION isms. This approach is referred to as the `modular- ity ofcognition' or `mental modules' approach. At 0559.001 What is the relationship between language and first glance it may seem contrary to the interdiscip- cognition? Do people who speak different lan- linary spirit ofcognitive science and to the possibil- guages think differently? Is a certain level of ity ofa unified theory ofcognition. However, the cognitive development required for language ac- unifying theory is the thesis of distinct mental quisition? These questions were ofkeen interest to modules, which are believed to have evolved to thinkers in the early twentieth century and remain accomplish specific tasks relevant to mammalian important in anthropology, linguistics and psych- evolution, such as visual exploration, or relevant ology. However, the cognitive revolution ofthe to human evolution, such as language use. Much of 1950s brought a new question about the relation- the appeal of this approach comes from findings in ship between language and cognition: is language neuropsychology showing that distinct areas ofthe the same type ofmental entity as other cognitive brain serve distinct functions such as vision, lan- abilities, or is it fundamentally different? guage processing, motor coordination, memory, 0559.002 A hallmark ofmodern cognitive science is the and face recognition. The interdisciplinary spirit is goal ofdeveloping a theory ofcognition powerful maintained because advocates ofthis approach enough to encompass all human mental abilities, reach out to biological scientists and evolutionary including language abilities. A long-standing con- theorists. Those favoring modularity embrace the troversy concerns two ways ofconceptualizing the principle ofconverging methodologies: a theory architecture (or basic design) ofcognition. One ap- must have explanatory power in the distinct aca- proach proposes that general-purpose processes demic disciplines that compose the cognitive sci- and mechanisms provide a foundation for all var- ences. These two approaches to the architecture of ieties ofhuman intelligence. We can referto this as cognition developed out ofdifferentphilosophical `general purpose' cognition. Examples ofpossible traditions, and have evolved considerably during universal processes are the ability to induce a the half-century history of cognitive science. category from exposure to examples (category in- duction), and the ability to mentally complete a known pattern when confronted with a piece of it CONCEPTS OF COGNITION AND (pattern completion). Cognitive scientists fre- LANGUAGE quently attempt to precisely specify their proposed Why are there two different views on the relation- mechanisms by implementing them as computer 0559.004 ship between language and cognition? At the dawn algorithms which can be tested in artificial intelli- ofthe cognitive revolution, in the late 1950s, there gence (AI) programs. Researchers have tried to use were two distinct ideas about the nature ofmind. AI programs to show that the same principles that Discussed first are the views of linguist Noam can explain general problem-solving can also Chomsky and the field of generative linguistics explain aspects oflanguage acquisition and pro- cessing. Galley: Article - 00559 2 Language and Cognition which he developed, because the underlying phil- or speakers' communicative goals came to be called osophy has remained fairly constant over the inter- the `autonomy ofsyntax' hypothesis. vening years. Chomsky's innovations developed in tandem 0559.007 0559.005 Chomsky's major innovation was to conceive of with the dawn ofthe cognitive revolution. With language abilities as akin to a mental organ. the birth ofcomputer science a new way ofconcep- According to this view, children are born with a tualizing human cognition arose, using the meta- `language acquisition device' and with specific lin- phor ofthe brain as a computer and the mind as guistic knowledge. This knowledge is thought to software. Much of Chomsky's early work include the concepts ofnoun, verb, grammatical depended on this metaphor: he conceived ofgram- subject, and structures that constrain possible mar as a set ofrules forgenerating novel combin- grammatical rules. In contrast to the views ofthe ations ofwords, just as a computer program could dominant psychological theory ofthe 1950s, behav- generate a string ofsymbols according to a formula. iorism, Chomsky argued that children do not learn Thinking ofmental operations as akin to steps in a to speak by imitating adults. His key evidence was computer program allowed psychologists and that children spontaneously use incorrect forms workers in the new field of artificial intelligence to they could not have heard, like `goed' and begin to subdivide mental tasks, such as arithmetic `breaked'. Linguistic overregularizations like these or language comprehension, into a series ofsteps in suggest that children are extracting rules from the a computer program. Their research evolved in a language they hear, not merely imitating. Theorists different direction from Chomsky's. Computer sci- at that time found it noteworthy that parents do not entists and psychologists such as Alan Newell, generally tell children that their utterances are un- John Anderson, Roger Schank and Patrick Winston grammatical. Because the language input to chil- began to describe a range ofhuman abilities ± from dren is full of mistakes, stops and restarts, visual object recognition and general problem solv- Chomsky felt that children could not learn lan- ing, to metaphor use and story understanding ± in guage using general purpose problem-solving or terms ofa set ofinternal representations and pro- regularity-extraction skills. They needed to come cesses that transform those representations. A key to the task with a rich set ofexpectations about aspect ofthis approach to cognition was that the the nature oflanguage. These expectations were theorist could write computer programs that believed to be specific to language, and thus did would provide a formalizable theory of mental op- not share commonalities with other aspects ofcog- erations. A rigorous test ofthe theory could be nition. This set oflanguage-specificabilities has performed by running the program and seeing if been variously called the `language acquisition output matched human output. device' (the historically early term) and `universal Many ofthe early successes ofthis fieldinvolved 0559.008 grammar' (a more recent term). Chomsky's ap- language, including sentence comprehension, story proach to linguistics is called `generative linguis- understanding and metaphor use. An important tics' because its early goal was to describe mental aspect ofthe language and cognition relationship structures that can generate all the grammatically is that the AI models oflanguage did not draw on valid sentences ofa language. language-special algorithms or knowledge struc- 0559.006 Chomsky felt that the aspect of language that is tures. The new AI tradition and the information unique is syntactic ability. An example ofspecific- processing movement within psychology empha- ally syntactic knowledge is illustrated by the sen- sized learning, particularly general-purpose learn- tence, `Colorless green ideas sleep furiously'. ing, and was thus opposed to the emphasis on Although the words in this sentence contradict innate knowledge structures that was part of each other and do not correspond to a possible Chomsky's new linguistics. Psychologists drawn reality (green is not colorless, ideas cannot sleep to the information processing movement were fre- furiously), speakers nevertheless recognize the sen- quently inspired by the work ofSwiss psychologist tence as having a correct grammatical structure. Jean Piaget, whose works began to be translated Chomsky used this sentence as an example of into English in the 1960s. Piaget also emphasized how syntactic structure represents information in- the commonalities between language and cogni- dependently from the meaning of the words in the tion, and proposed that language emerged out of sentence. He argued that syntax is a unique, inde- the same broad cognitive changes that transform pendent human capacity and not derivative from the sensorimotor processing ofinfantsinto the other abilities. The proposal that syntax is not influ- formal and logical mind of adults. enced by the meaning ofthe words in the sentence In the 1970s and 1980s, among those researchers 0559.009 who aligned themselves with the interdisciplinary Galley: Article - 00559 Language and Cognition 3 field of cognitive science, there was a tendency for units (neurons), linked together in a complex linguists to emphasize the specialness oflanguage network of fiber tracts, with many units firing sim- and cognition, and for psychologists to emphasize ultaneously. This