The Cambridge Handbook of Communication Disorders examines the full range of developmental and acquired communication disorders and provides the most up-to-date and comprehensive guide to the epidemiology, aetiology and clinical features of these disorders.
AUTHOR: W. Tecumseh Fitch TITLE: The Evolution of Language PUBLISHER: Cambridge University Press YEAR: 2010
Anne Reboul, Laboratory on Language, the Brain and Cognition, Institute for Cognitive Sciences, Lyon, France
The present book is intended as an introduction to the evolution of language, conceived of as the unique preserve of mankind. Fitch intends it to be a dispassionate exposition of the various theories advanced by various scholars and the data which supports or contradicts those views. The book consists of an introduction and four distinct and sections of unequal length: ''The lay of the Land: an overview of disciplines and data relevant to language evolution'', ''Meet the ancestors'', ''The Evolution of Speech'', and finally ''Evaluating phylogenetic models of language evolution''.
The ''Introduction'' insists both on the complexity of language and the resulting diversity of perspectives about it, ranging from Chomskyan linguistics to the psycholinguistics of language acquisition via neuroscientific approaches, and advocating an inclusive rather than divisive approach, combining the valuable insights in the different approaches and aiming at a comparison-based synthesis. From there, the first section opens with a chapter devoted to ''Language from a biological perspective''. Fitch pinpoints the inability of chimpanzees, man's nearest relatives phylogenetically, to acquire language and advocates a comparative approach to language based on a multi-component view: in other words, though no animal species has anything remotely like human language, some species may have this or that component or, at least, a predecessor to it. Fitch then introduces two meanings of the phrase ''faculty of language'', a broad sense which ''encompasses ALL the mechanisms involved in language acquisition and use'' (21, his emphasis), and a narrow sense targeting ''those mechanisms that are both unique to humans and special to language'' (22). Fitch argues that most components are indeed shared with other species, which opens the road to a comparative approach. He then distinguishes ''communication'' and ''language'', the former common to all species while the latter is uniquely human. Language can be fairly described as an ''instinct to learn''. Fitch then distinguishes between I-language (the cognitive system underlying language in each individual's brain) and E-language (the languages spoken by different human communities).
Chapter 2, ''Evolution: consensus and controversy'', begins with a historical description of the emergence of Darwin's natural selection, based on three factors, variation, inheritance and differential survival. Fitch distinguishes and describes three kinds of selection, sexual (one sex, usually the females, picks the sexual partners, based on criteria which will then predominate in the species), kin (based on the notion of inclusive fitness, where the degree to which genes are shared can boost cooperation) and group selection (extending inclusive fitness to the group). The comparative method is a tool for the description of evolutionary history, leading to the construction of phylogenetic trees, based on clades. It allows the identification of both homologous traits (shared through inheritance from a common ancestor, showing the species' phylogenetic history) and analogous traits (shared through independent evolution in different species, showing the function of a trait). Fitch concludes with the evolution of behavior, reminding the reader of Tinbergen's famous four-layered approach to animal behavior, in terms of ''mechanism'', ''function'', ''ontogeny'' and ''phylogeny''.
The third chapter, ''Language'', begins with a link between the existence of sensitive periods for language acquisition and the biological basis of language. It then naturally turns to biolinguistics, after a brief description of the Chomskyan approach to linguistics as mental (cognitive), formal and biological. Fitch points out that though parts of language can be seen as encapsulated in a Fodorian sense, that is, as informationally closed (e.g., speech), other parts are executive and unencapsulated (e.g., semantics and pragmatics). In other words, there is room in language for both individual and cultural levels of explanation and contemporary evolutionary theory can bridge them, through the coevolution of cultural and biological systems. Fitch then outlines the components of language, following the traditional distinction between phonology, syntax, semantics and pragmatics.
The fourth chapter turns toward ''Animal cognition and communication'', repudiating behaviorist approaches and defending cognitive achievements such as episodic memory, categorical perception and mindreading in animals, as well as more wide-ranging capacities, such as categorization and learning, planification, inference and reasoning, numerosity, cross-modal matching and serial ordering. Fitch also emphasizes the existence of ''animal cultures''. Animals thus evidence a number of cognitive abilities potentially relevant for language, a conclusion which is reinforced by the fact that different vertebrate species, from birds to sea mammals to dogs and apes have been shown to be able to master ''large referential vocabularies''. Fitch then turns to animal communication systems, highlighting the fact that most animal signals are innate (in contrast with words) and have an emotional basis though they can still be under voluntary control. However, some animal signals have a rule-based structure, and some even have a phonological syntax, though meaningful syntax is fairly sparse (a two signal-concatenation in some species of monkeys). Though there are functionally referential signals (alarm or food calls, notably), these are not intentional in a Gricean sense, but the interpretation of such signals, especially by non-conspecifics, can be inference-based.
Section 2, ''Meet the ancestors'', opens with an eponymous chapter going from the origins of life to modern humans. The goal of the chapter is to introduce the notion of ''latest common ancestor'' or LCA (between humans and chimpanzees, their nearest relatives).
Chapter 6, ''The LCA: our last common ancestor with chimpanzees'', describes the characteristics which may legitimately be attributed to the LCA on the basis of man-chimpanzee comparisons: communication, sociality, tool use, hunting and medicine, violence, and limited male parental care.
Chapter 7 is devoted to ''Hominid paleontology and archaeology'', and it gives a clear and detailed overview of the state of the art, outlining three stages in human evolution from the LCA: the emergence of bipedal apes (early Australopithecines) from about 4-2 million years ago (MYA); an increase in body and brain size and the use of more complex tools comes with the birth of the genus ''Homo'' (by 1.9 MYA); and the final stage with so-called ''archaic Homo sapiens'', including Neanderthals, and finally the appearance on the scene of anatomically modern Homo sapiens or AMHS (by between 100-200 KYA) which spread all over the globe leaving their birth place, Africa, by 50 KYA. This date provides the latest possible date of the evolution of modern language, given its universality.
Section 3, ''The evolution of speech'', opens with chapter 8, ''The evolution of the human vocal tract''. Fitch begins by distinguishing between speech and language, noting that though language is massively realized in speech, the existence of signed languages shows that the two are distinct. He describes the physiological apparatus by which animal vocalizations (including speech) are produced, noting the commonalities among vertebrates. He then turns to the descended larynx, pointing out that despite common belief, it is not specific to humans, and is more likely to have been the object of sexual selection (for size exaggeration in males) than a specifically linguistic adaptation. Fitch discusses the hyoid bone in various hominid fossils. However, given the existence of a mobile or descended larynx in many nonhuman species, it is probably not relevant to any discussion on the evolution of language. He notes that phonological categorical perception seems widespread in vertebrates and thus is, again, unlikely to be a specific adaptation for language.
In chapter 9, ''The evolution of vocal control: the neural basis for spoken language'', Fitch identifies the ability for complex vocal imitation as crucial for human speech and, after having pointed out the limited existence of that ability in nonhuman species (where it is mainly limited to some birds, and to sea mammals), he turns to the brain mechanisms which underlie human speech. Though most of them are common among mammals (birds have different kinds of brains), there are novel cortico-laryngeal connections in humans, which argue for a discontinuity between primate and human vocal control. Additionally, the discovery of the FOXP2 gene and its importance for the development of complex vocal motor control -- this gene, though widely shared with other mammals, seems to have evolved in its human form about 400 KYA and, when deficient, produces specific language impairment -- argues for the same conclusion.
Chapter 10, ''Models of the evolution of speech and phonology'', discusses four models of speech evolution, from Lieberman's model (which attributes a central role to the basal ganglions), to MacNeilage's (which outlines the link between vocal motor control and motor control for feeding), to Deacon's (a selective pruning of cerebral connections leading to the cortico-laryngeal connections typical of humans), ending with Carstairs-McCarthy's view that vocal motor control was a product of bipedalism. Fitch then turns to the question of the evolution of the phonological structure itself, discussing perceptual constraints, vocal imitation, glossogeny (or cultural transmission), pidgins and creoles and describing computer simulations of ''invisible hand'' models for language change.
Section 4, devoted to ''Evaluating phylogenetic models of language evolution'', opens with a ''Historical overview: Western theories of language origin before Darwin''. After a short mention of the biblical Genesis story, Fitch turns to Herder's onomatopoetic theory of word origins, to various expressive theories, to theories of language as a social tool and to Müller's anti-Darwinian theory. He then outlines Darwin's theory of language evolution, based on the idea of a sexually selected musical protolanguage, which would lead to a meaningful modern language through increased intelligence.
Chapter 12, ''Lexical protolanguages'', turns to various accounts of a putative pre-syntactic proto-language, having as prerequisites both vocal imitation and a drive for referential communication. Fitch discusses Bickerton's model (under which infant speech, ape language and pidgins are supposed to be models of protolanguages), but rejects Bickerton's notion that syntax appeared through a single ''macro-mutation''. He turns to Jackendoff's model, which insists on lexical acquisition tools (based on the limited size of ape vocabulary) and a combinatorial phonology. Both models assume the drive for communicating information. However, such a drive would clearly involve cooperation and cooperation is something of an evolutionary mystery. Fitch then outlines several theories for the evolution of cooperation before turning to Dunbar's social theory (gossip, leading to social sanctions against free-riders, is a good way of promoting cooperation), rejecting some aspects of Dunbar's views, but keeping others. He then turns to Deacon's account in terms of the evolution of the social structure and feeding patterns of hominid groups, before outlining his own theory, in three stages: kin selection for information exchange, leading to reciprocal altruism through gossip, and, finally, syntax.
Chapter 13 deals with ''Signs before speech: gestural protolanguage theories'', describing several accounts which propose a gestural protolanguage, concluding that they all meet with a major hurdle: why, if language was gestural, and given that sign languages show that full communication can be achieved through gestures, did the shift to vocal communication occur? The recent discovery of mirror neurons does not solve the problem.
Chapter 14, ''Musical protolanguage'', outlines Fitch's favorite candidate for the evolution of language. He reminds us of several arguments for strong links between language and music, including shared cerebral structures, and of Darwin's account. The problem with the notion of a musical protolanguage, which would not be meaningful, is how to account for a passage from meaningless holophrases to meaningful combinatorial and discrete units. Here, Fitch turns to Wray's account where semantic meaning is supposed to be ultimately derived from coincidences between meaningless and noncombinatorial sounds in holophrases and potential meanings. He defends it against criticisms by outlining Kirby's computational model of the holistic/analytic transition, showing such a transition to be possible.
Chapter 15 concludes, reminding the reader of Fitch's sympathy for the musical protolanguage hypothesis and of the rapid growth of data relevant to the field of the evolution of language.
This is an excellent book, which gives a detailed and precise account of the current state of the field, as well as historical background to both the central questions and different solutions which have been proposed. The comparative perspective is wide ranging and always well-informed, if slightly optimistic on animal capacities: for instance, though there is no doubt that animals have categorical abilities -- indeed, it would be hard to imagine how they could be entirely deprived of them --, this does not mean that their conceptual abilities are in the human range and the existence of conceptual hierarchies seems fairly limited. (Apes seem to be the only candidates to date: see Vonk & MacDonald 2002, 2004.) Again, it seems slightly misleading to say that animals can have important vocabularies (''hundred of items'' are mentioned more than once), when in fact the upper bound seems to be between 200 and 250 items, which is very far from, for instance, first-graders' lexicons (estimated at around 6000 words). Finally, though Fitch claims to maintain an aloof stance and not to push any theory, he clearly defends musical protolanguage theories, and some arguments given seem rather flimsy. Though no one disputes the existence of ''formulaic'' utterances in present day languages, this has nothing to say about the probability of a holistic/analytic transition given that obviously the transition in that case goes in the reverse direction: idioms or formulas are made up of discrete units which come in some phrases to lose their individual meaning, and this, if anything, illustrates an analytic/holistic transition. Nevertheless, the book is impressive thanks to its erudition, clarity and precise discussions of data, theories and arguments. It is a must for anyone interested in the evolution of language.
Vonk, J. & MacDonald, S.E. (2002) ''Natural concepts in a juvenile gorilla (Gorilla gorilla gorilla) at three levels of abstraction'', in Journal of experimental analysis of behavior 78, 315-332.
Vonk, J. & MacDonald, S.E. (2004) ''Levels of Abstraction in orangutan'', Journal of comparative psychology 118, 3-13.
ABOUT THE REVIEWER
ABOUT THE REVIEWER:
Anne Reboul is a Senior Researcher at the French Center for Scientific
Research (CNRS) in France. She has a Ph.D. in Linguistics (EHESS, Paris)
and a Ph.D. in philosophy (University of Geneva, Switzerland). Her books
include an Encyclopedic Dictionary of Pragmatics and numerous papers in
French and English, on pragmatics and/or philosophical subjects. She has
developed an interest in recent years in both language evolution and animal
cognition and communication and has recently published a book on language
and human cognition.