Primate Communication and Human Language: Vocalisation, gestures, imitation and deixis in humans and non-humans edited by Anne Vilain, Jean-Luc Schwartz, Christian Abry and Jacques Vauclair (Advances in Interaction Studies Series, Vol. 1: John Benjamins Publishing Company)
After a long period where it has been conceived as iconoclastic and almost forbidden, the question of language origins is now at the center of a rich debate, confronting acute proposals and original theories. Most importantly, the debate is nourished by a large set of experimental data from disciplines surrounding language. The editors of Primate Communication and Human Language have gathered researchers from various fields, with the common objective of taking as seriously as possible the search for continuities from non-human primate vocal and gestural communication systems to human speech and language, in a multidisciplinary perspective combining ethology, neuroscience, developmental psychology and linguistics, as well as computer science and robotics. New data and theoretical elaborations on the emergence of referential communication and language are debated by some of the most creative scientists in the world.
Editors of the volume are Anne Vilain, Universite de Grenoble and GIPSA-Lab; Jean-Luc Schwartz, CNRS GIPSA-Lab, Grenoble; Christian Abry, Stendhal University (Grenoble, 1971-2009); and Jacques Vauclair, Universite de Provence, Aix-en-Provence.
As the subtitle reads, the central concepts that are manipulated in Primate Communication and Human Language are vocalizations, gestures, imitation and deixis, and they are addressed in different ways, through the multiple directions explored to bring material for the issue of phylogenetic continuities towards language, and in particular, to fuel the lively debate on the vocal vs. gestural theories of language origins.
The first question to be investigated is: what do we know about primate communication? New ethological studies will help readers understand the nature and the status of the vocal and gestural communication of apes and monkeys. The basic idea underlying these studies is that a good precursor for human language should be a system with a large variety, specific use, adaptability, learnability and complexity. A large number of behavioral field observations and experimental studies are now being run in primate societies, both in the wild and in captivity, that will give answers to these questions.
Yet no phylogenetic continuity could be assessed without knowledge of the cortical analogies between the non-human and the human control of the communication systems. So behavioral data needs to be complemented by neurophysiological studies comparing the brain circuits for the vocal and gestural modalities of human and non-human primate communication. Studies on the volitional control of vocalizations and gestures, on their cortical networks, and on their links with the perceptuo-motor systems in the brain attest very clear structural and functional similarities between the vocal and the manual communication modalities, and set them as two potential precursors of human language. Specific action-perception circuits in the brain have been shown to be the basis of imitation mechanisms and even action understanding systems, so their investigation reveals the learnability of gestures and vocalizations.
Such a strong interweaving of vocal and manual modes in primate communication and brain evidently brings in the question of how these two motor systems are associated in human language, and particularly in its development. The multi-modal nature of human communication is now a widely acknowledged field of research, and both developmental and behavioral data show how closely voice and gestures are related in the acquisition and adult proficiency of oral language. And one of the crucial nodes of this common structuration appears to be the basic function of deixis. Deixis, a primary and very early element in the development of language, enables the individual to attract the attention of other individuals towards a selected focus of interest, and possibly opens a route towards reference and linguistic predication.
The comparative and developmental perspectives described previously do not really mean to solve the question of language origins, but they literally show us where language comes from. This enables us to better understand how language has been shaped by this evolutionary and developmental pathway, or in other words, to reveal a set of cognitive continuities and constraints that could have played a role in the way language units are built and combined. This opens the route to substance-based theories of phonological systems, which should attempt to 'derive language from non-language'. And this constitutes the last question in Primate Communication and Human Language: can computational models capture one or the other of these cognitive constraints and put them inside a computationally tractable scenario from which some of the properties of human language could be simulated and hopefully better understood?
Primatology including strong views from neurosciences developmental studies, phonetics and computation have now been invited in Primate Communication and Human Language in order to attempt to better describe and understand the links between all metaphorical figures of primates: Monkeys/Apes, Infants, Humans and Robots, in the search for continuities and constraints on language and speech.
And so while it is true that language represents a major difference between humans and other primates, the editors believe that it actually derives from the uniquely human abilities to read and share intentions with other people which also underwrite other uniquely human skills that emerge along with language such as declarative gestures, collaboration, pretense, and imitative learning".
Primate Communication and Human Language brings in arguments from three different directions of studies on language evolution. The first part produces new behavioral and neurophysiological findings about the complexity, adaptability and control of primate vocal communication. The second part questions the possible continuities from orofacial and manual gestures to human language, with neurophysiological, behavioral and ontogenetic data. The third part deals with the emergence and development of language through the integration of all these components, with data from developmental psychology, phonetics and computational simulations.
At the end, the editors have at their disposal a number of data and proposals relevant for the project: vocalization, communicative gestures, imitation and deixis actually seem to provide important pieces towards a communication system already available in non-human primates, and developed at an immensely elaborate stage in human language. Clearly, the major questions of language phylogeny remain unsolved and are actually not addressed in Primate Communication and Human Language such as: why did this immense improvement occur, and how did sophisticated functions of language such as elaborate syntax or referential semantics emerge and develop? Moreover, many disciplines in the language phylogeny consortium were ignored, such as genetics or, to a large extent, linguistics.
However, the basic question of continuities and precursors in primate communication is clearly enlightened. In the light of data and findings described in Primate Communication and Human Language, it appears that the writing of a convincing scenario for language emergence can hardly escape from a strong involvement of both the hand and the mouth in a closely coordinated way. Everything seems to converge in this claim: the evidence for both relatively sophisticated oral and gestural communication in monkeys and apes, their coordination in apes and through human language development, their common mirror neuron system. The expanding spiral emergence scenario proposes an interesting potential framework, in which a number of questions remain open, concerning the ability of each of these systems to push or pull the other one towards more sophistication, from all relevant sides including learning, decomposition, sequencing, reference.