Language Evolution

April 25, 2000

Everybody read:

Smith, J.M. and E. Smathmary. 1995. Chapter 17: The evolution of language. In The major transitions in evolution. New York: W.H. Freeman and Co.: 281-309.
(An entertaining, easy read)

OR

Pinker, S. 1997. Evolutionary biology and the evolution of language. In M. Gopnik (ed.) The inheritance and innateness of grammars. New York: Oxford University Press: 181-208. (A very good background on the different views of the evolution of language…a little denser than Smith and Smathmary)

Theories of language evolution

Pinker, S. and P. Bloom. 1990. Natural language and natural selection. Behavioral and Brain Sciences 13(4): 707-784.
Many people have argued that the evolution of the human language faculty cannot be explained by Darwinian natural selection. Chomsky and Gould have suggested that language may have evolved as the by-product of selection for other abilities or as a consequence of as-yet unknown laws of growth and form. Others have argued that a biological specialization for grammar is incompatible with every tenet of Darwinian theory -- that it shows no genetic variation, could not exist in any intermediate forms, confers no selective advantage, and would require more evolutionary time and genomic space than is available. We examine these arguments and show that they depend on inaccurate assumptions about biology or language or both. Evolutionary theory offers clear criteria for when a trait should be attributed to natural selection: complex design for some function, and the absence of alternative processes capable of explaining such complexity. Human language meets this criterion: grammar is a complex mechanism tailored to the transmission of propositional structures through a serial interface. Autonomous and arbitrary grammatical phenomena have been offered as counterexamples to the position that language is an adaptation, but this reasoning is unsound: communication protocols depend on arbitrary conventions that are adaptive as long as they are shared. Consequently, language acquisition in the child should systematically differ from language evolution in the species and attempts to analogize them are misleading. Reviewing other arguments and data, we conclude that there is every reason to believe that a specialization for grammar evolved by a conventional neo-Darwinian process.

Botha, Rudolf P. 2000. Discussing the evolution of the assorted beasts called language. Language & Communication 20(2): 149-161.
Evaluates research on language evolution in relation to their compliance with the condition of ontological transparency. Different ontological characterizations of the concept of language; Analysis of language structure and the existing disconnected, inconclusive discussions of specific questions of language evolution.

Ganger, J. and K. Stromswold. 1998. Innateness, evolution, and genetics of language. Human Biology 70(2): 199-213.
Our goal in this article is to review a debate over the evolution of language and to suggest some keys to its resolution. We begin with a review of some of the theoretical and empirical evidence for the innateness of language that has caused renewed interest in the evolution of language. In a second section we review some prominent theories of the evolution of language, focusing on the controversy over whether language could have been adapted for some purpose. We argue that for evolutionary studies of language to advance, theorists must make more persuasive arguments for the purpose of language, and, furthermore, linguists must continue to develop a detailed theory of syntax. Finally, we suggest ways that behavioral and population genetics could help to inform studies of the evolution of language.

Lieberman, P. 1990. The evolution of human language. Seminars in Speech and Language 11(2): 63-76.

Nowak, M.A., J.B. Plotkin, and V.A.A. Jansen. The evolution of syntactic communication. Nature 404: 495-498.

Aiello, Leslie C. 1996. Terrestriality, bipedalism and the origin of language. In Runciman, W.G., J.M. Smith and R.I.M. Dunbar (eds.) Proceedings of the British Academy, 88; Evolution of social behavior patterns in primates and man. London: Oxford University Press: 269-289.
Language is unique to humans, but in the context of the long time span of human evolution it is a fairly recent innovation. All evidence suggests that human brain size and inferred cognitive and linguistic abilities reached their modern norms only within the last quarter of a million years. Foundations for human linguistic and cognitive evolution, however, lie much further back in evolutionary history. Arguments are presented suggesting that these unique human abilities are the legacy of our ancestors' terrestrial and bipedal adaptations. Both terrestriality and bipedalism are directly associated with the unique human propensity for vocal communication, including the range and quality of sound that all humans are capable of producing. Furthermore, terrestriality and bipedalism can also be directly associated with brain size and cognition. Increases in group size accompanying a committed terrestrial adaptation would have put a premium on social, or Machiavellian intelligence while bipedalism would have been associated with the increased neural circuitry involved in enhanced speed and co-ordination of hand and arm movements. The constricted bipedal pelvis would have also necessitated the birth of less mature offspring, exposing them to a rich environment while the brain was still rapidly growing and developing. A larger brain is not without its costs, however. Energetic arguments are also presented which suggest that a large brain can only evolve in concert with a change to a high quality diet, resulting directly in lifestyle changes for our early ancestors. All of the features were in place by the appearance of early Homo erectus about 1.8 million years ago and underpinned an apparently stable hominine adaptation that lasted for well over 1.5 million years. Modern human cognitive and linguistic talents are rooted in this earlier Homo erectus adaptation and may have begun to develop in response to further need for increased group size. Both the costs and the benefits of this later increase in brain size are considered.

Transition

Nowak, M.A., D.C. Krakauer, and A. Dress. 1999. An error limit for the evolution of language. Proceedings of the Royal Society Biological Sciences Series B 266(1433): 2131-2136.
On the evolutionary trajectory that led to human language there must have been a transition from a fairly limited to an essentially unlimited communication system. The structure of modern human languages reveals at least two steps that are required for such a transition: in all languages (i) a small number of phonemes are used to generate a large number of words; and (ii) a large number of words are used to a produce an unlimited number of sentences. The first (and simpler) step is the topic of the current paper. We study the evolution of communication in the presence of errors and show that this limits the number of objects (or concepts) that can be described by a simple communication system. The evolutionary optimum is achieved by using only a small number of signals to describe a few valuable concepts. Adding more signals does not increase the fitness of a language. This represents an error limit for the evolution of communication. We show that this error limit can be overcome by combining signals (phonemes) into words. The transition from an analogue to a digital system was a necessary step toward the evolution of human language.

Ujhelyi, M. 1996. Is there any intermediate stage between animal communication and language? Journal of Theoretical Biology 180(1): 71-76.
Animal communication and human language have fundamental differences in their structures and functions. Furthermore, there is no living species demonstrating an intermediate stage of language evolution. Thus, we have difficulty in finding characteristics attributable to a communication system which can already be considered as a starting point for linguistic evolution. However, some findings coming from neurolinguistic research give us the opportunity to suppose that varying and arranging linguistic elements can be detached from other grammatical functions. Further information in this direction comes from apes' language-teaching experiments; namely bonobos (Pan paniscus) are able to understand and produce differences in meaning by varying word arrangements. Based on these results one can suppose that an acoustic signal system, which possesses discrete units for variable use, might be very ancient and might exist independent and prior to a more advanced language state. In the natural setting, acoustic territorial marking behaviour is exposed to selection pressure to elaborate sign systems built up from discrete, variable units. In addition to the well-known territorial bird songs, some monkey species and all species of lesser apes have territorial songs fitting these criteria. The analyses of the so-called long calls in chimpanzees and bonobos make it likely that the group-living great apes preserved the ability to create syntactically different calls, which would be developed by requirements of social life. A call repertoire emerged in these species, which contained a large number of call variants at group level available for each group member via social learning. This type of animal call is different from ordinary animal communication; it shows some features of human language. It can represent an intermediate stage between animal communication and language, and communication systems similar to this one can be considered as a starting point or first stage of language evolution.

Ujhelyi, M. 1998. Long-call structure in apes as a possible precursor to language. In Hurford, J.R., M. Studdert-Kennedy, and C. Knight (eds.) Approaches to the evolution of language. Cambridge: Cambridge University Press: 177-189.

Locke, J. J. 1998. Social sound-making as a precursor to spoken language. In Hurtford, J.R., M. Studdert-Kennedy, and C. Knight (eds.) Approaches to the evolution of language. Cambridge: Cambridge University Press: 190-201.

Bickerton, D. 1998. Catastrophic evolution: the case for a single step from protolanguage to full human language. In Hurtford, J.R., M. Studdert-Kennedy, and C. Knight (eds.) Approaches to the evolution of language. Cambridge: Cambridge University Press: 341-358.

Corballis, M. 1999. The gestural origins of language. American Scientist 87(2).
Human language is one of the finest accomplishments of biological evolution. Much of our species’ success is fundamentally dependent on the capacity of language to generate ideas that allow us to escape from the immediate present or to describe events and phenomena that have never existed. Yet the origin and evolution of this powerful tool is quite mysterious. Other forms of animal communication bear so little resemblance to human language that it seems unlikely that any of them could be a precursor to spoken language. Pulling together various observations on the neurology of language, the sophistication and cross-cultural nature of sign languages, and the ability of apes to communicate with signs, Corballis argues that the origins of human language may lie in manual gestures, not in vocalization.

Arbib, M.A. and G. Rizzolatti. 1997. Neural expectations: A possible evolutionary path from manual skills to language. Communication and Cognition 29: 393-424.

Games and models

Nowak, M.A. and D.C. Krakauer. 1999. The evolution of language. PNAS 96(14): 8028-8033.
The emergence of language was a defining moment in the evolution of modern humans. It was an innovation that changed radically the character of human society. Here, we provide an approach to language evolution based on evolutionary game theory. We explore the ways in which protolanguages can evolve in a nonlinguistic society and how specific signals can become associated with specific objects. We assume that early in the evolution of language, errors in signaling and perception would be common. We model the probability of misunderstanding a signal and show that this limits the number of objects that can be described by a protolanguage. This "error limit" is not overcome by employing more sounds but by combining a small set of more easily distinguishable sounds into words. The process of "word formation" enables a language to encode an essentially unlimited number of objects. Next, we analyze how words can be combined into sentences and specify the conditions for the evolution of very simple grammatical rules. We argue that grammar originated as a simplified rule system that evolved by natural selection to reduce mistakes in communication. Our theory provides a systematic approach for thinking about the origin and evolution of human language.

Nowak, M.A., J.B. Plotkin, and D.C. Krakauer. 1999. The evolutionary language game. Journal of Theoretical Biology 200(2): 147-162.
We explore how evolutionary game dynamics have to be modified to accommodate a mathematical framework for the evolution of language. In particular, we are interested in the evolution of vocabulary, that is associations between signals and objects. We assume that successful communication contributes to biological fitness: individuals who communicate well leave more offspring. Children inherit from their parents a strategy for language learning (a language acquisition device). We consider three mechanisms whereby language is passed from one generation to the next: (i) parental learning: children learn the language of their parents; (ii) role model learning: children learn the language of individuals with a high payoff; and (iii) random learning: children learn the language of randomly chosen individuals. We show that parental and role model learning outperform random learning. Then we introduce mistakes in language learning and study how this process changes language over time. Mistakes increase the overall efficacy of parental and role model learning: in a world with errors evolutionary adaptation is more efficient. Our model also provides a simple explanation why homonomy is common while synonymy is rare.

Warneryd, K. 1995. Language, evolution, and the theory of games. In Casti, J.L. and A Karlqvist (eds.) Cooperation and conflict in general evolutionary processes. New York: John Wiley and sons: 405-421.

Hurford, J.R. 1991. The evolution of the critical period for language acquisition. Cognition 40(3): 159-202.
Evidence suggests that there is a critical, or at least a sensitive, period for language acquisition, which ends around puberty. The existence of this period is explained by an evolutionary model which assumes that (a) linguistic ability is in principle (if not in practice) measurable, and (b) the amount of language controlled by an individual conferred selective advantage on it. In this model, the language faculty is seen as adaptive, favoured by natural selection, while the critical period for language acquisition itself is not an adaptation, but arises from the interplay of genetic factors influencing life-history characters in relation to language acquisition. The evolutionary model is implemented on a computer and simulations of populations evolving under various plausible, if idealized, conditions result in clear critical period effects, which end around puberty.


Related works for additional reading

Gibson, K.R. and T. Ingold (eds.) 1993. Tools, language and cognition in human evolution. Cambridge: Cambridge university press.

Hornstein, N. 1996. From icons to symbols: some speculations on the origins of language. In Brandon, R. N. (author) Cambridge studies in philosophy and biology; concepts and methods of evolutionary biology. Cambridge: Cambridge university press: 85-105.

Haldane, J.B.S. 1992. Animal communication and the origin of human language (reprint). Current science (Bangalore) 63(9): 604-611.

Lieberman, P. 1984. The biology and evolution of language. Cambridge, Mass.: Harvard University Press.

Lieberman, P. 1991. Uniquely human: the evolution of speech, thought, and selfless behavior. Cambridge, Mass.: Harvard University Press.

Lieberman, P. 1998. Eve spoke: human language and human evolution. New York: W.W. Norton.