Language: A Darwinian Adaptation?
Knight, C., M. Studdert-Kennedy and J. R. Hurford, (2000). Language: A Darwinian Adaptation? In C. Knight, J. Hurford and M. Studdert-Kennedy (eds), The Evolutionary Emergence of Language: Social function and the origins of linguistic form. Cambridge : Cambridge University Press, pp. 1-15.
Let me just ask a question which everyone else who has been faithfully attending these sessions is surely burning to ask. If some rules you have described constitute universal constraints on all languages, yet they are not learned, nor are they somehow logically necessary a priori, how did language get that way? Stevan Harnad, in a conference question to Noam Chomsky (Harnad, Steklis and Lancaster 1976: 57)
As a feature of life on earth, language is one of science’s great remaining mysteries. A central difficulty is that it appears so radically incommensurate with nonhuman systems of communication as to cast doubt on standard neo-Darwinian accounts of its evolution by natural selection. Yet scientific (as opposed to religious or philosophical) arguments for a discontinuity between human and animal communication have come into prominence only over the past 40 years. As long as behaviourism dominated anglophone psychology and linguistics, the transition from animal calls to human speech seemed to offer no particular difficulty (see, for example, Mowrer 1960; Skinner 1957). But the generative revolution in linguistics, begun with the publication of Noam Chomsky’s Syntactic Structures in 1957 and developed in many subsequent works (e.g. Chomsky 1965, 1966, 1972, 1975, 1986; Chomsky and Halle 1968) radically altered our conception of language, and posed a challenge to evolutionary theory that we are still striving to meet.
The central goal of Chomsky’s work has been to formalise, with mathematical rigour and precision, the properties of a successful grammar, that is, of a device for producing all possible sentences, and no impossible sentences, of a particular language. Such a grammar, or syntax, is autonomous with respect to both the meaning of a sentence and the physical structures (sounds, script, manual signs) that convey it; it is a purely formal system for arranging words 1 (or morphemes) into a pattern that a native speaker would judge to be grammatically correct, or at least acceptable. Chomsky has demonstrated that the logical structure of such a grammar is very much more complex and difficult to formulate than we might suppose, and that its descriptive predicates (syntactic categories, phonological classes) are not commensurate with those of any other known system in the world, or in the mind. Moreover, the underlying principle, or logic, of a syntactic rule system is not immediately given on the surface of the utterances that it determines (Lightfoot, this volume), but must somehow be inferred from that surface – a task that may defeat even professional linguists and logicians. Yet every normal child learns its native language, without special guidance or reinforcement from adult companions, over the first few years of life, when other seemingly simpler analytic tasks are well beyond its reach.
To account for this remarkable feat, Chomsky (1965, 1972) proposed an innate ‘language acquisition device’, including a schema of the ‘universal grammar’ (UG) to which, by hypothesis, every language must conform. The schema, a small set of principles, and of parameters that take different values in different languages, is highly restrictive, so that the child’s search for the grammar of the language it is learning will not be impossibly long. Specifying the parameters of UG, and their values in different languages, both spoken and signed, remains an ongoing task for the generative enterprise.
By placing language in the individual mind/brain rather than in the social group to which the individual belongs, Chomsky broke with the Saussurean and behaviouristic approaches that had prevailed in anglophone linguistics, and psychology during the first half of the twentieth century. At the same time, by returning language to its Cartesian status as a property of mind (or reason) and a defining property of human nature (Chomsky 1966), Chomsky reopened language to psychological and evolutionary study, largely dormant since The Descent of Man (Darwin 1871).
We have no reason to suppose that Chomsky actually intended to revive such studies. For although he views linguistics as a branch of psychology, and psychology as a branch of biology, he sees their goals as quite distinct. The task of the linguist is to describe the structure of language much as an anatomist might describe that of a biological organ such as the heart; indeed, Chomsky has conceptualised language as in essence the output of a unitary organ or ‘module’, hard-wired in the human brain. The complementary role of the psychologist is to elucidate language function and its development in the individual, while physiologists, neurologists and psychoneurologists chart its underlying structures and mechanisms. As for the evolutionary debate, Chomsky has had little to offer other than his doubts concerning the likely role of natural selection in shaping the structure of language. This scepticism evidently stems, in part, 2 from the belief (shared with many other linguists, e.g. Bickerton 1990 and Jackendoff 1994) that language is not so much a system of communication, on which social selection pressures might indeed have come to bear, as it is a system for mental representation and thought. In any event, Chomsky has conspicuously left to others the social, psychological and biological issues that his work has raised.