[Extracted from: J.M.G. van der Dennen, D. Smillie and D.R. Wilson eds. 1999. The Darwinian Heritage and Sociobiology, Chapter 5, 67-81. Westport, CT: Praeger.] >

EVOLUTION AND CULTURE: THE MISSING LINK

Robin Allott

The relation of evolution and culture has been much debated. There have been many different approaches, of which the most notable have been those of Cavalli-Sforza and Feldman, Lumsden and Wilson, and Boyd and Richerson. Also noteworthy are the views of Durham and Hinde and most recently of the evolutionary psychologists. If these other accounts, or any one of them, seems to cover the subject adequately and to be intellectually satisfying, no new approach would be needed. The first step then is to summarize and assess the theories that have been presented.


Theories

Cavalli-Sforza and Feldman (1981) adopted a quantitative approach. After pointing out that up to that date cultural transmission had received little attention they stressed the need for a theory of cultural change; they chose to develop a mathematical theory since the modern theory of biological evolution owed much of its strength to the mathematical background, primarily in population genetics. They sought to deal with the dynamics of the changes within a population of the relative frequencies of the forms of a cultural trait under defined cultural interactions, whilst recognizing that for humans it is difficult to partition the process of transmission into purely genetic and purely cultural components. Cultural traits varied in significance; there were relatively trivial ones (innovations such as the spread of CocaCola, volleyball etc.) where participation in the trait could not appreciably alter the probability of surviving or having children; in these instances some kind of non-Darwinian selection was involved which they termed 'cultural'. Other traits were important elements of culture (notably language); these were subject to processes analogous to those in biological evolution to which the concepts of drift and migration could be applied. Cultural selection could act counter to natural selection, although harmony between the two was expected on average, based on the assumption that the neural structures or mechanisms that permit choice evolve under the control of natural selection which thus indirectly controls the scope of cultural choices made.

Lumsden and E.O. Wilson (1981, 1983) postulated that human cultural transmission is ultimately gene-culture transmission. Their aim was the technical development of a theory of gene- culture coevolution, a first attempt to trace development all the way from genes through the mind to culture. The approach, similar to that of Cavalli-Sforza and Feldman though more mathematically ambitious, centred round the concept of the culturgen [producing culture], the basic unit of inheritance. They derived the concept from the operational units of culture in archaeology (artifacts) but extended it to cover all kinds of transmissible behaviours, mentifacts, and artifacts, The transmission of culturgens was governed by epigenetic rules, the genetically determined peripheral sensory filters, inter-neuron coding processes, and cognitive procedures of perception, learning and decision-making. These together affected the probability of one culturgen being transmitted rather than another. Genetic and cultural evolution drive each other forward; culture is created and shaped by biological processes, while the biological processes are simultaneously altered in response to cultural change.

Boyd and Richerson (1985) presented a Darwinian theory of the evolution of cultural organisms. By culture they meant the transmission from one generation to the next, via teaching and imitation, of knowledge, values, and other factors that influence behaviour. The basic point of departure for their dual inheritance model was the analogy between genes and culture; the relationship between them was, they said, the most interesting scientific problem presented by human evolution. The evolution of the structure of cultural transmission in humans was analogous to the evolution of the genetic system. Genes and culture are mechanically distinct systems of inheritance, but behaviour is the product of predispositions resulting from genetic inheritance alone and predispositions resulting from cultural inheritance alone.

Others have approached the relation between cultural and biological evolution from other standpoints, ranging from Rindos, who argued (1985) that cultural evolution is explainable by exactly the same processes as underlie genetic evolution with selection as the ultimate determinant, to Hinde (1982) who suggested that natural and cultural evolution can to some extent proceed independently but many everyday actions may nevertheless depend on propensities selected in another context to promote individual fitness. Most recently the evolutionary psychologists have promoted a novel but still Darwinian view of mental organization and so of cultural behaviour. Perhaps one should recall Dobzhansky`s (1951: 304) observation that human genetics has not been superseded by human culture; the former remains the foundation which enables man to manifest the kinds of behaviour which are called social and cultural. The interrelationships between biology and culture are reciprocal.

Assessment

Ingold comments severely but perhaps justly on the various attempts to give a theoretical or systematic account of the relation of culture and biological evolution and particularly the elaboration of formal models of gene-culture coevolution by Boyd and Richerson, Cavalli-Sforza and Feldman, Lumsden and Wilson: "Not much can be said for their models in their present state of development, the assumptions on which they rest are either so remote from reality or so ultimately trivial that they do not so much advance our understanding of evolutionary processes as provide an excuse for the exercise of mathematical ingenuity." (1986: 364) The authors themselves recognized the necessarily preliminary and speculative character of their pioneering work. Boyd and Richerson said they were acutely aware that the dual inheritance model of human evolution rested on less than completely compelling arguments; for the present the purpose of theory could only be to summarize a state of quite imperfect knowledge about the causes of human behaviour in a way which would make further refinement as simple as possible. This comment can equally well be applied to the work of Cavalli-Sforza and Feldman and Lumsden and Wilson.

Unresolved difficulties or lacunae in the different approaches relate to the concept of culture, the lack of empirical evidence to test the various mathematical models, uncertainty about the cultural significance of symbols, the role of language in the evolution of culture, absence of specific examination of major segments of culture, the hypothesis of unitary cultural traits analogous to genes, emphasis on the transmission of culture and neglect of the more important problem of the creative aspect of human cultural development, the origins of particular cultural systems. One of the main impressions left by the varying coevolutionary accounts is a certain fogginess about the idea of culture. More than a hundred definitions of culture have been proposed by anthropologists and others; the authors of the coevolutionary theories add to the number. The definition used by Cavalli-Sforza and Feldman is a modified version of that in Webster's dictionary: the total pattern of human behaviour and its products embodied in thoughts, speech, action, and artifacts, and dependent upon man's capacity for learning and transmitting knowledge to succeeding generations; the transfer of abstract instructions and explanations in ways that do not require face- to-face observation and direct imitation; for them the term cultural included all sorts of activities, from technology to entertainment, and all sorts of beliefs, values and behaviours. Lumsden and Wilson defined culture to include the sum total of mental constructs and behaviour, including the construction and employment of artifacts; they acknowledged the preeminence of symbols in human culture but also classed as cultural a substantial class of imitative behaviours. Boyd and Richerson discussed at some length the most appropriate definition of culture, pointing out that in anthropology, the term 'culture' is used in many different and only partially overlapping senses; "Culture is information capable of affecting individuals' phenotypes which they acquire from other conspecifics by teaching or imitation" (1985: 33). They did not restrict culture to behaviour encoded by symbolic constructs such as language, myth or ritual nor, unlike other approaches, did they assume the existence of units - 'discrete particles' - of cultural inheritance such as memes or culturgens. For the evolutionary psychologists Tooby and Cosmides (1992), culture is the manufactured product of psychological mechanisms situated in individuals living in groups which evolved by natural selection in the evolutionarily stable environment of the Pleistocene.

This paper is concerned with human culture in the broadest sense (originally adopted by Tylor): essentially the whole complex of behaviours, structures and processes that make us human. Culture should be seen primarily not as an accumulation of artifacts or of what Lumsden and Wilson call mentifacts but as behavioural potential for the creation of culture in the individual and in human society. The key question is the evolutionary source of the potential. What is needed is theory which deals adequately and specifically with the origin, transmission and change of the central non-trivial aspects of human culture: language, morality, social systems, science, the arts, religion. Whilst what distinguishes cultural evolution from genetic evolution is transmission by non-biological means, cultural origins and the source of variations are as important as the mechanisms of transmission.

In the Descent of Man (1871) Darwin considered at some length such major aspects of human culture as morality and language but did not attempt to deal with high culture. In his autobiography he described how he became blind or deaf to music, poetry, mathematics, philosophy, art: "Now for many years I cannot endure to read a line of poetry: I have tried lately to read Shakespeare and found it so intolerably dull that it nauseated me. I have also almost lost any taste for pictures or music ... I am so utterly destitute of an ear, that I cannot perceive a discord, or keep time, or hum a tune correctly"; he spoke about "not being able to see any meaning in the early steps in algebra". At the university he was what Matthew Arnold would have termed a Philistine: "my time was sadly wasted there and worse than wasted [drink dissipation, riding] ... How I did enjoy shooting". Nevertheless "I cannot help looking back on that time with much pleasure". (1876: 58, 60-61, 138)

Culture as a symbolic system?

For the most part, later writings on coevolutionary theory also fail to deal specifically with the major aspects of human culture. Partly this may have been the result of over-emphasis on cultural units, traits, culturgens, memes, rather than cultural systems. The other contributing factor seems to have been a limiting, and perhaps mistaken, view of the general character of culture as an aggregation of symbols, a consequence of taking language as the model, paradigm or prime example of cultural evolution generally. Though there were differences of emphasis between the authors whose coevolutionary theories have been summarized above, all of them comment on the symbolic character of culture, whilst rejecting some of the more extreme views of anthropologists. So Boyd and Richerson said that some of the most strenuous objections to human sociobiology came from the symbolic anthropologists who believe that symbols are the essential feature of human culture, often defining culture as a set of symbols whose meanings are shared by members of a human society but such a sweeping view was unsatisfactory unless it could be made consistent with the argument from natural origins: "The key defining feature of symbols is that they are arbitrary; in language it usually does not matter what sound pattern or what series of letters are used to signify a particular thing or concept; it only matters that the members of a speech community agree on some convention. Other cultural symbol systems are similar to language. Much of human behavior consists of the use and production of symbols" (1985: 272). Lumsden and Wilson identified the central importance in cultural evolution of a process they call reification for which the enabling device was symbolization; human language is largely the manipulation of symbols to convey the reified concepts of the mind; language is the means whereby culturgens are labelled and juxtaposed to assemble and communicate more complex knowledge structures; gene- culture coevolution was only possible because of the invention by the human species of reification, symbolization, and language.

The treatment of culture as a symbolic process is not new; Sol Tax (1960: 280) said that cultural behaviour has a quality of arbitrariness, because it does not flow through the genes and is therefore not anchored in the individual, as seen most clearly in the arbitrariness of the symbols of language. Cavalli-Sforza and Feldman also developed their account of cultural evolution using the development and differentiation of languages as prime examples of cultural phenomena, with considerable parallelism between genetic and linguistic evolution: the formation of two or more different languages from a single predecessor as an analogue of speciation. Language and its components (words, rules, and sounds) could be regarded as cultural 'objects'. Other aspects of language touched on by Cavalli-Sforza and Feldman included the correlation of linguistic and genetic variation between populations (as extensively developed in Cavalli-Sforza's later publications), the distribution of surnames, vowels as examples of continuously variable traits, the acquisition of language by children of foreign parents. In the learning of language, they commented, genetics might seem a priori to be unimportant but given the difference between man and animals it was unavoidable to conclude that language has a genetic basis despite the present impossibility of proof.

The concept of the symbol, in language or otherwise, can lead one far astray, and can be even more misleading if one assumes that a symbol must necessarily be arbitrary. The character and origin of the symbol has been the subject of much controversy; the relation between symbol and the external world is not simple. A symbol may be arbitrary or it can be the physical product of the process or object which it symbolizes - or a symbol can be structurally related to the process or object which it symbolizes or a symbol can be generated by unconscious processes of association or imitation ultimately dependent on brain organization and function. To assume that language is symbolic, that language is the prime example of a human cultural phenomenon, and that therefore cultural traits are also essentially symbolic and arbitrary makes a bad starting point for any theory of the relation of cultural and biological evolution.

In summary, one is forced to conclude, with Ingold, that the approaches or theories of cultural evolution presented by these authors are not convincing, not satisfactory or adequate. They deal essentially with cultural transmission and the arguments tend to be circular; culture for them is what is transmitted culturally. They say little or nothing about the human potential for the creation of culture, about the major aspects of culture in human evolution, about the evolutionary source of the potential and of the content and form of the major cultural systems. Even in terms of their account of the transmission of culture, the idea (which most of them espouse) that culture is atomistic, composed of culturgens, cultural traits, memes, etc seems mistaken or at least misleading. Their accounts of cultural transmission, heavily mathematicised in ways derived directly from population genetics, remain at an abstract level with little or no attempt to apply them to real cultural content. But if these approaches are unsatisfactory what new or different approach to the relation of biological evolution and culture is possible?

Language as the link

The new approach proposed is a revived stress on language as the foundation of culture, as the source of the human cultural potential, as the mode of transmission and of change of cultural systems, as the form through which cultural systems are originated and stabilised. Language has a much greater importance in relation to cultural evolution than the probably mistaken use of it as the archetypal symbolic, arbitrary cultural system. Much of what is classified as culture is preserved in language, transmitted over time by language, conveyed from parent to child by language. At the level of society, virtually every major aspect of human culture is language dependent, social systems, kinship classifications, morality, custom, science, group organisation, religion. For human culture, imitation without any linguistic context is a much less important mode of cultural transmission; even the transmission of technologies is heavily dependent on language. At the level of the individual, patterns of behaviour, patterns of thought, are also language-dependent. Darwin stressed the wider importance of language in the development of human culture. After drawing attention to the curious parallels between the formation of different languages and of distinct species: "If we possessed a perfect pedigree of mankind, a genealogical arrangement of the races of man would afford the best classification of the various languages now spoken throughout the world; and if all extinct languages, and all intermediate and slowly changing dialects, were to be included, such an arrangement would be the only possible one" (1871: 402). More significantly he commented on the fundamental importance of language in human evolution: "It is not the mere power of articulation that distinguishes man from other animals ... but it is his large power of connecting definite sounds with definite ideas ... the relation between the continued use of language and the development of the brain has no doubt been far more important [than language simply as a means of communication] ... it may well be that [self-consciousness, abstraction etc.] are incidental results of other highly-advanced intellectual faculties; and these again are mainly the result of the continued use of a highly-developed language." (105) "A great stride in the development of the intellect will have followed, as soon as, through a previous considerable advance, ... language came into use; for the continued use of language will have reacted on the brain and produced an inherited effect; and this again will have reacted on the improvement of language. The large size of the brain in man ... may be attributed in chief part ... to the early use of some simple form of language - that wonderful engine which affixes signs to all sorts of objects and qualities." (390) Besides the evolutionary contribution of language to the development of mind, as suggested by Darwin, language has made human culture in its totality possible. The significance of language is not only what it contributed to human evolution hundreds of thousands of years ago, but its contribution now both in the social maintenance of culture and in advancing understanding of brain function. Lashley years ago said that language is the only window we have on the mind and though we have modern scanning technologies, PET, MRI, MEG which allow us to inspect the working of the brain, language remains the most specific and discriminating mode of insight into the mind. The current importance of language is obvious.

The source of the power of language

Rather than considering the appearance of language in human evolution as the product of some mysterious general symbolizing capacity, we need a genetic (physiological and neurological) theory of language origin and language function; a physiological theory of language origin and function would constitute the missing link in the relation between evolution and culture. The new approach leads necessarily to the question of the source of the culture-forming and culture-transmitting power of language, both as a current phenomenon and as the key development in the advance of the human species. To understand the current role of language in human individual mentality and in human social organization, one has to attempt to go back to the origins, the vital but neglected issue of the evolutionary origin of language. This is a topic which, after neglect during the 19th century and continuing neglect by mainline linguists, has come to assume a much greater importance; there is a rapidly growing literature on the subject, with accounts which differ both as regards the evolutionary mechanisms proposed and the theories of language adopted.

In 'mainline linguistics' if this is an appropriate term for the Chomskyan approach, Chomsky accepts that language acquisition is the result of innate factors but rejects any possibility of giving a classical Darwinian account of language origin by natural selection. His linguistic theories have changed radically over the years; by slow steps he has moved away from his long obsession with syntax as the essence of language and come to appreciate more fully language as the interaction of syntax and lexicon. His account of Universal Grammar has been based very heavily on the peculiarities of English, in which word order plays the central role; an approach less appropriate for other languages which rely on highly differentiated lexical structures with word order as a subsidiary process. There is nothing remarkable about word order - words can only be uttered serially - as you can only perform actions serially and syntax is very largely implemented through words. Chomsky suggests that the unordered super-rules (principles) are universal and innate, and that when children learn a particular language, they do not have to learn a long list of rules, because they were born knowing the super-rules. All they have to learn is whether their particular language has the parameter head-first, as in English, or head- last, as in Japanese as if the child were merely flipping a switch to one of two possible positions. This general conception of grammar is called the 'principles and parameters' theory, and is the latest in a line of theories from Syntactic Structures in 1957, moving from transformational-generative grammar centred on the idea of 'deep structure', to government and binding in 1980. Many would not accept Chomsky's current account as a useful basis for considering the evolution of language.

Pinker and others

With these introductory remarks about Chomskyan linguistics one can turn to Steven Pinker's book The Language Instinct, which is the most recent, comprehensive and ambitious attempt to account for the origin of language. It approaches the topic from within the Chomskyan framework, unusual since Chomskyan linguists have generally remained silent about language evolution. Pinker offers an evolutionary account of language based on the idea that it evolved, step by minimal step, adaptively by natural selection, in exactly the same sort of way as that proposed by Darwin (and refined by Dawkins) for the evolution of the eye, or, also as proposed by Darwin, for the evolution of animal instincts. Language, Pinker says, is not a cultural artifact but `a distinct piece of the biological make up of the brain`; the task is to explain the evolution of Universal Grammar as a brain module or organ. Chomsky's concept of a Universal Grammar is well known: the brain must contain a recipe or program that can build an unlimited number of sentences from a finite list of words; the program may be called a mental grammar; children - 'grammatical geniuses' - must innately be equipped with a plan common to the grammars of all languages that tells them how to extract the syntactic patterns from the speech of their parents. Pinker does not share Chomsky's scepticism about whether Darwinian natural selection can explain the origins of the language organ. At a number of important points, Pinker's account seems unsatisfactory, for example: the idea that language could have developed, like the eye, by minute steps, under the pressure of natural selection. the idea that eventually neuroscientists will be able to locate a 'language organ', or behavioural geneticists discover a grammar gene, the postulation of a uniform distinct language of thought, mentalese, to be translated into any particular spoken language, his discussion of the arbitrariness of the sign, his account of the acquisition of language by children.

These criticisms both of the Chomskyan account of language and of Pinker's attempt to present a gradualistic account of the evolution of language as a distinct function, instinct or organ are dealt with at greater length in a recent paper for the meeting of the Language Origins Society at Pecs, Hungary (Allott 1995c). Piattelli-Palmarini (1994: 339), an enthusiast for Chomsky, says that Pinker's account (developed with Paul Bloom) is the best, yet still unconvincing, adaptationist reconstruction. In Pinker's book there is much little-examined speculation, about the time when the first rudiments of language might have emerged, about the manner in which children can acquire lexicon, about the anthropological basis for improved language capacity, about the role of genetic mutation in bringing about changes in language structures, about the possibility of survival benefit for the individual flowing from mutations affecting language competence and performance. The principal error is the failure to treat adequately the social character of language, as a possession of the group, of the speech community, and not simply of the individual. Language development and change as increasing the inclusive fitness, that is serving the long- term reproductive success of the individual, is simply not a plausible proposition. The other major error is concentration on the evolution of syntax, grammar, and treating superficially the vital role of the development of lexicon, both as a representation of the perceived world and as an instrument for syntactic manipulation of utterances through function words, inflections etc. The final and perhaps most important error is a mistaken view of natural selection as limited to gradualistic change in a complex structure serving a specified function; natural selection also operates through serendipitous transfer of complexity developed for one function to a new function, typically the move from swim-bladder to lung, from webbed foot to wing, from gill to structures of the ear and so on.

Nor is it necessary to spend much time on the treatment of language in the recent book (1995) by Maynard Smith and Szathmary. For them language is the fifth major transition in evolution; they disclaim any special knowledge of linguistic theory; in their account of the evolution of language they say that they rely heavily on two sources, Bickerton (1990) and Pinker (and Bloom)'s scenario of language evolving by minimal steps. Whilst adopting the evolution of language and of the eye as parallel processes, they recognize the difficulties of accounting in this way for the step-by-step evolution of Chomskyan grammar. The criticisms already mentioned in relation to Pinker's account apply equally to that produced by Maynard Smith and Szathmary.

A different approach

If both the Chomskyan approach to language and the gradualistic account of language evolution are rejected, what alternatives are there? Any theoretical approach to language has to go wider than phrase structure and cope with the elaborated systems of grammar and lexicon found in many world languages. Other approaches follow a quite different tack: reject the idea that language could have emerged gradually by minute steps following the pattern of individual natural selection with inclusive fitness related to minor improvements in the language capacity. Suggest instead another type of verified evolutionary origin: the construction of new biological functions on the basis of systems which had evolved for other purposes. Darwin and others have given accounts of this kind of evolution e.g. the swimbladder serving a new purpose as an air-breathing lung, the evolution of gills into the structures of the ear, the conversion of the forefoot for locomotion into the hand for grasping, the conversion of webfeet for movement in water into surfaces for gliding or flying. Evolutionary accounts of language following this different approach look to the transfer to form a capacity for language from previously developed perceptual or motor systems, changes in brain organization which made possible the development of the complexities of language.

The idea that language may have been modelled on or directly derived from pre-existing brain systems has been explored by a number of writers. The possibilities include modelling on tool use (Greenfield, Parker, Gibson and others), modelling on the visual system (Givon), modelling on throwing action (Calvin), modelling on motor control (Studdert-Kennedy, Lieberman, Allott). The earliest suggestion on these lines was by Karl Lashley (1951) who discussed the generality of the problem of syntax and drew attention to the parallels between the syntax of language and the syntax of action; there has since been considerable discussion of the grammar of action and of the grammar of vision Richard Gregory (1976). It is not possible in this paper to present these alternatives at any length but the following paragraphs briefly describe them.

Greenfield's 1991 paper "Language, tools and brain: The ontogeny and phylogeny of hierarchically organized sequential behavior" postulated an evolutionary homologue of the neural substrate for language production and manual action which provided a foundation for the evolution of language before the divergence of the hominids and the great apes. The role of toolmaking as a precursor for or as coevolving with language has been extensively discussed. Perhaps it should be treated as the first approach to investigating the relation between language and the cerebral motor control system.

Studdert-Kennedy (1983) suggested that linguistic structure may emerge from, and may even be viewed as, a special case of motoric structure, the structure of action; later he added that for language, the goal is to derive its properties from other, presumably prior, properties of the human organism and its natural environment; "we should try to specify the perceptual and motor capacities out of which language has evolved" (1983: 329); evidence from brain stimulation (notably the work of Kimura, Ojemann and Mateer) almost forced the hypothesis that the primary specialisation of the left hemisphere is motoric rather than perceptual; language would be drawn to the left hemisphere because the left hemisphere already possessed the neural circuitry for control of the fingers, wrists and arms, precisely the type of circuitry needed for control of the larynx, tongue, velum, lips and of the bilaterally innervated vocal apparatus. Ojemann and Mateer (1979, 1991) identified common cortical sites for sequencing motor activity and speech; language arises at least in part in brain areas that originally had a predominantly motor function; the development of language seems to have incorporated brain mechanisms originally developed for motor learning.

Givon in a paper for the 1994 Berkeley meeting of the Language Origins Society took the system of visual perception as the basis on which language emerged in a process of coevolution; in this the evolution of language was linked directly to the development of the visual system. He discussed the correspondences between visual and linguistic information and suggested that language processing piggybacked on visual processing; in evolution there had been an early co-existence of auditory-vocal and visual- gestural codes; the rise of visual-gestural coding provided a neuro-cognitive preadaptation for a shift to audio-oral coding because of the adaptive advantages it offered, freeing the hand and body for other activities, transcending the immediate visual field. He developed these ideas in the light of recent evidence from PET scans and otherwise of brain localisation of particular aspects of language processing in relation to visual and auditory brain organization.

Lieberman (1984, 1991) has presented a motor theory of the origin of syntax. According to this, the evolution of speech and language follows from Darwinian processes; organs that were originally designed to facilitate breathing air and swallowing food and water were adapted to produce human speech. The development of language was an instance of the mechanisms of preadaptation which besides examples such as swim-bladders and lungs, produced the sometimes surprising preadaptive bases of various specialized organs, for example, milk glands from sweat glands, the bones of the mammalian middle ear from the joint of the lower jaw. The initial stage in the evolution of the neural bases of human language appears to have involved lateralized mechanisms for manual motor control, facilitating precise one- handed manual tasks. Brain mechanisms that allow the production of the extremely precise complex muscular manoeuvres of speech, the most difficult motor control task that humans perform, may have provided the preadaptive basis for rule-governed syntax which may reflect a generalisation of the automatic schema first evolved in animals for motor control in tasks like respiration and walking. A change in brain organization that allowed voluntary control of vocalization is the minimum condition for vocal communication.

Calvin (1989) argues the case for an even more specific preadaptation for the neural machinery underlying language in the neural circuitry required for planning sequential hand-movements such as hammering and throwing. Since hand-arm sequencing circuitry in the brain has a strong spatial overlap with where language circuitry is located in the left brain, perhaps the same massively-serial architecture can do double-duty for language and planning ahead. The well-formed sentence and the reliable plan of action have some strong analogies to more familiar darwinian successes, a matter of what Charles Darwin called "conversion of one function to another" or metamorphosis of function. To describe the original function from which the conversion of function was made, the better word is exaptation because of the 'preconceived' connotations of preadaptation. A given piece of anatomy can have more than one function. The conversion of function is an excellent candidate for how beyond-the-apes language abilities originated. Hominid-to-human language is a 'free' secondary use of neural sequencing machinery that was primarily shaped by the food-acquisition uses of ballistic movement skills.

In a number of papers (1989, 1992, 1994, 1995a,b,c) I have presented a comprehensive motor theory of language evolution and function. The theory proposes as a universal principle that the structures of language (phonological, lexical and syntactic) were derived from and modelled on the pre-existing complex neural systems which had evolved for motor control, the control of bodily activity. Motor control at the neural level requires pre-set elementary units of action which can be integrated into more extended patterns of action - neural motor programs. These in turn have to be linked to and integrated with one another by 'syntactic' neural processes and structures. On this theory, given that speech is also essentially a motor activity, language made use of the elementary pre-set units of motor action to produce the equivalent phonological units (phonemic categories); the neural programs for individual words were constructed from the elementary units in the same way as motor programs for bodily action are formed from them (in both cases a neural program is formed in direct relation to the perceived structure of the external world); the syntactic processes and structures of language proper were modelled on the 'syntactic' rules of motor control.

Chomsky, Pinker and Bloom, Piattelli-Palmarini argue against preadaptation on the basis of the visual or motor systems on grounds which are directly related to their perhaps idiosyncratic formal analysis of language, with its emphasis on syntax. So Piattelli-Palmarini (in a 1994 paper which argued strongly against Piaget's view that language was derived from or related to motor schemata) said that the form of linguistic principles is very specific e.g. c-command, X-bar, PRO, projection of a lexical head, trace of a noun-phrase etc. and went on to say that there is no hope, not even the dimmest one, of translating these entities, these principles, and these constructs into generic notions that apply to language as a 'particular case'; nothing in motor control even remotely resembles these kinds of notions; concrete linguistic examples (drawn from Chomskyan theory) make it vastly implausible that syntactic rules could be accounted for in terms of sensorimotor schemata. Chomsky in Language and Problems of Knowledge (1988) said the visual system is unlike the language faculty in many crucial ways; though there are some similarities in the way that the problems can be addressed, in relation to vision and language, the visual faculty does not include the principles of binding theory, case theory, structure dependence, and so on. The two systems operate in quite different ways. Pinker, Chomsky and Piattelli-Palmarini, in rejecting a preadaptive or exaptational basis for the evolution of language in the visual or motor systems of the brain because it is impossible to see how such as a basis could accommodate the formalisms of transformational-generative grammar, government and binding, or principles and parameters, ignore the unwelcome possibility that there is something fundamentally wrong with the linguistic theories, not with the Darwinian process by which there can be conversion of function from an already existing complex neural system for perception or action to serve as the basis for speech and language function. Chomsky is left in the awkward position of being unable to conceive of a Darwinian origin for language even though he asserts that it must have a biological basis; this leads Pinker to propose a gradualistic account of language evolution as the product of a series of minimal genetic and language changes, which is implausible in accounting for the step-by-step accretion of the elements required for Chomskyan phrase-structure theory, and even less plausible to account for the development of other complex grammatical and lexical features of world languages. The way out of the impasse is to see the evolution of language as a system founded on, reflecting and expressing the pre-existing complexities of the perceptual and motor systems of the brain.

Summary and conclusion

This paper suggests that a new approach to the relation between biological evolution and culture is needed; it considers whether the accounts of Cavalli-Sforza and Feldman, Lumsden and Wilson, Boyd and Richerson are adequate and concludes they are not. They deal essentially with cultural transmission; culture for them is what is transmitted culturally; they say little about the human potential for the creation of culture, about the major aspects of culture in human evolution, about the evolutionary source of the potential and of the content and form of the major cultural systems; the idea (which most of them espouse) that culture is atomistic, composed of culturgens, cultural traits, memes, seems mistaken; their discussion of cultural transmission remains at an abstract mathematical level. The new approach to the relation of biological evolution and culture takes the form of a revived stress on language as the foundation of culture, as the source of the human cultural potential, as the form through which cultural systems are originated and stabilised. The new approach leads on to the question of the source of the power of language in forming and transmitting culture, the biological basis of language. Steven Pinker bases his evolutionary scenario in The Language Instinct on Chomsky - the proposition that Universal Grammar and its principles and parameters are innate - but does not accept Chomsky's view that no explanation of these in classical Darwinian terms is possible; he suggests that language evolved as an instinct by natural selection, like other instincts, or as an organ, like the eye, by gradual advance through genetic change in individuals; genetic change resulted in language change which increased the fitness of the individuals affected, resulting in the wider dispersion of their language genes. The alternative to Pinker's unsatisfactory gradualistic account is one based on a different but well-recognized Darwinian evolutionary process, the construction of new biological functions, and structures, on the basis of systems or structures which had evolved for other purposes: preadaptation or exaptation. Evolutionary accounts following this different approach propose the formation of the language capacity by conversion or extension from previously developed perceptual or motor systems, by cerebral reorganization by which the complexities of language reflect the pre- existing complexities of the perceptuo-motor systems. With this, the relation between biological and cultural evolution loses a great deal of its mystery. Language is the biological link between culture and non-cultural aspects of human evolution both in its role in the development of the brain and cognition and in its continuing role, as part of brain organization and function, as the instrument for the preservation and transmission of culture from generation to generation. REFERENCES

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