Possible Continuity Theories of Language

Abstract

Serious difficulties with existing continuity theories of the relationship between human language and systems of communication in other animals have caused many linguists to reject the possibility of investigating this relationship. Some of the difficulties seem to be inherent in the assumption that continuity theories must be theories of comparative intellect. These difficulties can be avoided, however, by theories which place their major emphasis on the adaptive functions of communication systems in their ecological context. Recent work on the ontogeny of bird song provides a basis for such a theory, within which a new evaluation may be made of the significance of recent experiments on language abilities in chimpanzees. Theories on the origin of human language and its relationship to the communication systems of other animals have been grouped by Lenneberg 1967 into two types: continuity theories, which suggest that human language can be derived evolutionarily by well-understood processes operating on the kind of communicative display system general in the vertebrates; and discontinuity theories, which hold that human language is completely different from any known kind of communicative display system in other animals, that its evolutionary origins are not at all obvious, and that the study of animal communication probably will be of little use in increasing our understanding of human languages. To Lenneberg's dichotomy I should like to add another, between comparative-intelligence theories and ecological theories. Comparative-intelligence theories of the origins of language exist in both continuity and discontinuity guises. They emphasize that the crucial differences between human language and other communicative display systems lie in the structures of cognitive skills or 'forms of cerebration' (Lenneberg 1971:1), which are graded in phylogeny and which underlie the communicative system. Ecological theories, on the other hand, emphasize the adaptive properties of human language over other types of display systems in the particular selective contexts which were probably involved in the evolution of man. An emphasis on the role of intelligence or intellect is not necessarily central to their content. Further, they need not limit themselves to consideration only of man's close phylogenetic relatives. In the present paper, I review some properties of the comparative-intelligence kinds of theory, and show that a kind of theory based more closely in the ecological context of human evolution, and less in comparative intelligence, may make the beginnings of a continuity theory possible, in the sense that known processes of natural selection may be invoked to account for some aspects of human language. A careful investigation of the possibility of some form of continuity theory is