McGregor - Chapter 11 - Origins and evolution of human language.pdf

Language in its Biological Context 265 human language from animal communication systems. Nor does it favour the evolution of our language production and comprehension abilities from the general cognitive abilities of our ancestors...

Language in its Biological Context 265 human language from animal communication systems. Nor does it favour the evolution of our language production and comprehension abilities from the general cognitive abilities of our ancestors. Nevertheless, as observed at the beginning of §11.1, this lack of evidence does not argue for a non-evolutionary scenario, or for a separate language module in the mind. Indeed, overall it seems that the language abilities of human beings differ from the abilities of animals in degree rather than kind. The evidence suggests that some of the cognitive mechanisms involved in speech comprehension and production may have been in place prior to the emergence of human language. Perhaps the apparent qualitative differences between human language and animal communication systems are the result of the piling-up of quantitative differences. This brings us naturally to our next topic, the origin and development of human language. 11.3 Origins and evolution of human language Our unique ability to speak has inspired wonder and attempted explanations from time immemorial. Many, if not all, religions have myths accounting for language origins and/or diversification. Often a divine source is invoked. According to the Judean–Christian tradition, God gave Adam the power to name things; the Tower of Babel story accounts for the subsequent diversity of languages. Babylonians attributed language to the god Nabu, Egyptians to the god Thoth and Hindus to Sarasvati, wife of Brahma. According to some Australian Aboriginal societies, languages were implanted in particular tracts of country by mythical beings during the Dreamtime, a formative stage in which the world came to be as it is. The origin and evolution of human language is also of interest to science. We cannot, of course, observe the evolution of human language, and no records remain of the communicative systems used by our ancestors until the advent of writing (see Chapter 13). This means that we are restricted to the interpretation of other, indirect observational evidence. This does not make the study of origins and evolution of language unscientific: many fields of scientific endeavour are restricted to the interpretation of indirect evidence. One type of indirect evidence that might be brought to bear on the topic comes from ‘feral’ children, children who grow up in virtual social isolation, in circumstances in which they have been exposed to little or no language. A recent case is Genie, discovered in 1970 at the age of 14. Genie had been confined to a small room and had experienced only minimal human contact from the age of 18 months. Like other feral children, Genie spoke no language when discovered, nor did she subsequently learn one fully. Genie did, however, learn a relatively large vocabulary, though her syntax remained quite simple. She apparently went through many of the same early stages of acquisition that children normally go through (see §10.1). Introductory textbooks often refer to a report by the Greek historian Herodotus that in around 600 BCE the Egyptian pharaoh Psammetichus segregated two newborn infants in an isolated mountain hut with a shepherd, who was instructed to allow no one to speak 266 Linguistics in their presence. The pharaoh’s idea was that in isolation from linguistic input they would speak the original human language. The first word they produced was reported to have been bekos. This was discovered to be the word for ‘bread’ in Phrygian, a now extinct Indo-European language spoken in the north-west of modern Turkey. Thomas (2007) shows that this is a mythical interpretation of what Herodotus wrote that has no foundation in the text itself, which does not indicate that Psammetichus’s goal was to determine the original human language by experiment. Accounts of others (including King James IV of Scotland) who did similar experiments to determine the original human language also appear to be tall tales. Nineteenth-century theories of language origins The 19th-century linguist Friedrich Max Müller, a staunch anti-Darwinian, suggested a famous classification of theories of language origins, distinguishing the ‘la-la’, the ‘bow-wow’, the ‘ding- dong’, the ‘pooh-pooh’ and the ‘yo-heave-ho’ theories. The ‘la-la’ (or ‘sing-song’) theory sees the origins of human language in a communication system resembling bird song (see §11.1). The Danish linguist Otto Jespersen favoured this theory, presenting an idyllic Rousseauan view of humankind’s origins: The genesis of language is not to be sought in the prosaic, but in the poetic side of life; the source of speech is not gloomy seriousness, but merry play and youthful hilarity … In primitive speech I hear the laughing cries of exultation when lads and lassies vied with one another to attract the attention of the other sex, when everybody sang his merriest and danced his bravest to lure a pair of eyes to throw admiring glances in his direction. Language was born in the courting days of mankind. (Jespersen 1922: 433–4) The ‘bow-wow’ theory proposes that human language began with mimicry of natural sounds of the environment. A bird’s or animal’s call might be imitated, and this imitation used to refer to the creature; or a noise might be imitated and used as a verb to denote an event associated with the noise – for example, splash, bang and crash. According to this view, language origins lie in iconic rather than arbitrary signs. The ‘ding-dong’ theory also holds that language originated in natural connections between meanings and sounds. These could be iconic connections, as in the imitation of physical sounds. Alternatively they might be indexical connections, as in the case of mama for ‘mother’, supposedly deriving from the sound made by a baby as its lips approach its mother’s breast. According to the ‘pooh-pooh’ theory language originated in natural cries of emotion such as anger or pain, as when someone utters yow or ouch in pain, or yuck as an expression of distaste. Darwin championed this theory. The ‘yo-heave-ho’ theory proposes that the sounds uttered by persons when engaged in strenuous physical exertion provide the source of earliest language. The grunts and groans that are  Language in its Biological Context 267 naturally emitted in circumstances of exertion might then have taken on other meanings or senses in social contexts, perhaps being interpreted by hearers as requests for assistance. While the ‘bow-wow’, ‘ding-dong’, ‘pooh-pooh’ and ‘yo-heave-ho’ theories may account for some words in human languages, especially interjections and onomatopoeic lexemes, it is difficult to see how they can explain much more. It is not clear why or how morphology or syntax arose at all. As for the ‘sing-song’ theory, why would we have anything but unanalysable songs (holophrases) used in a delimited range circumstances? Why didn’t these songs remain the domain of one of the sexes, as in the case of birds? What drove the emergence of utterances analysable into components on both levels, form and meaning – i.e. duality of patterning? More recent theories of language origins In 1866 the Linguistic Society of Paris imposed a ban on papers on the origins of human language, a restriction it reaffirmed in 1911. Until recently linguists have by and large supported the senti- ments of the ban on the grounds that investigations of origins can only be speculative and, in the absence of technology for time-travel, unverifiable. Anthropologists, archaeologists, geneticists, psychologists, neurobiologists and others have been more daring, and have not shied from speculation informed by findings in their disciplines. It is only in the last couple of decades that linguists themselves have turned attention again to the question of origins, and the domain has become accepted as a field of investigation. Even today, however, many linguists consider it to be too speculative to permit investigation by scientific means. While it is true that one can only speculate, speculation does play a role in science. And serious speculations will perforce be constrained and informed by the fields within which the investigator works. If there is convergence in the speculations and findings across different fields one may feel more confident in a speculation. The area provides a good domain for interdisci- plinary research, provided one enters it with an open mind, and does not adopt the rhetorical stance of some linguists who stipulate that only linguists have the warrant to make statements about language origins – for surely this is an area where we cannot rely on a single discipline. In the following subsections I outline with a very broad brush a few of what seem to me to be the more interesting recent proposals about language origins. No attempt is made to be comprehensive: there are far too many theories to mention in an introductory survey; some are too complex to summarize in a few paragraphs, and have been left out for that reason. Nor do I attempt to be critical – all the proposals are based on circumstantial evidence, and can be fairly easily critiqued on the grounds that they leave unexplained a rack of known facts about the structure and/or functions of human language. In other words, at best they might account for the emergence of a communicative system of complexity less than that of human language; all take recourse to much hand-waving. Gestural origins One popular notion, with a long history, is that human language originated in bodily gestures that were later transferred to the vocal medium. Our ancestors such as the australopithecines 268 Linguistics may have communicated with bodily signs before their vocal tracts were capable of speech. One attraction of this idea is that apes have intentional control of manual gestures but not of vocali- zations (see §11.2), and the same was presumably true of our common ancestor, and likely also of some of the descendant hominid species. Following Max Müller’s lead, we will refer to this theory as ‘noddy’. The main problem with ‘noddy’ is how to account for the switch from manual gestures to vocal gestures. Perhaps over a long period of time manual gestures became increasingly accompanied by vocalizations, which may have begun with grunts; this process may have continued until the point was reached where the balance shifted from primacy of the visual to primacy of the vocal. This shift could have been sustained and enhanced by practical advantages such as the possibility of using vocalizations in the dark, and the freeing up of the hands for other tasks, thus allowing one to carry out manual activities at the same time as speaking. But it would have necessitated biological changes to both the vocal organs and the brain. The advent of bipedalism some five or six million years ago was, according to some (e.g. Corballis 2003, 2012; Lieberman 2003), a crucial first step in these biological changes. Alternatively, a genetic mutation that occurred some time in the last 100,000 years may have been responsible (Corballis 2003). Michael Arbib (2003, 2011, 2012) has suggested that biological evolution led to a language- ready brain, a key development being the evolution of the system of mirror neurons that link production and perception of motor acts of grasping. Intriguingly, these are found in a region of the cortex of a monkey’s brain that is considered to be the analogue of Broca’s area. As Arbib observes, it is not really that a switch occurred in the development of human language from the manual to the vocal medium; rather, the relative load of the latter increased. Facial and manual gestures arguably form with speech a single multi-modal communication system, as also argued by gesture theorists such as David McNeill (see also §12.1). The grooming hypothesis Robin Dunbar (1996, 2010, 2012) proposes the grooming hypothesis – the ‘yackety-yack’ theory – which assigns primacy to the interpersonal and social dimensions in the emergence of language. He observes that grooming is the favoured mechanism amongst primates for bonding social groups. However, human groups tend to be too large – in the order of 150 members – for grooming to be viable. Individuals would need to spend about 40 per cent of their waking day grooming; given that this is time during which they could do little else, it is far too much to be practicable. (The highest proportion of time observed among any primate is half of this, among Gelada baboons.) Speech provides a means of grooming at a distance; it can also be done while engaged in other activities, and is not restricted to pairs – multiple partners can be groomed simultaneously. As Dunbar observes, much of our everyday use of language is in gossip, which can be seen as an investment in the verbal servicing of social relationships. The social character of language is further supported by the preferred topics of natural conversation: social topics, he avers, make up around two-thirds of conversation time, whereas instrumental topics (work, tool manufacture and use, etc.) make up only 10–20 per cent.  Language in its Biological Context 269 Language as a genetic predisposition Everyone agrees that we are genetically adapted for speech: although both the baby and the rattle are exposed to the same linguistic input, only the baby acquires language. The human brain and/ or mind cannot be a tabula rasa. What investigators disagree on is the extent of our genetic endowment, whether the minimal view that our genes give us a language-ready brain or the maximal view that we have a genetic blueprint for language. Two divergent opinions are held by those who maintain the maximal position, which we’ll call the ‘just genes’ theory. On the one hand there are those who, like Chomsky, suggest that language arose in one unique and isolated biological event, as the result of a single genetic mutation and not by the normal evolutionary process of natural selection (Chomsky 1986) – the ‘Oops!’ theory. On the other hand there are investigators like Stephen Pinker who argue that language is a biological adaptation that evolved in the human species via the normal evolutionary process of natural selection. Language is, according to Pinker’s story – the ‘chatting-up’ theory4 – an innate speciali- zation that evolved for the encoding of propositional information in a form that permits it to be conveyed from one individual to another. If the ‘Oops!’ theory is correct, a single gene ought to be responsible for language. A possible candidate for this is the FOXP2 gene, the first gene to be shown to be relevant to language. A mutation in this gene was shown by geneticists in 2001 to be associated with a type of language disorder – called Specific Language Impairment (SLI) – characterized by articulation difficulties and grammatical impairments. However, it seems increasingly unlikely that a single gene could be responsible for language.5 This counts against the single mutation scenario, and in favour of the natural selection scenario. Thus, language is not completely wiped out in those individuals showing the mutation in FOXP2, and other genes have been shown to be associated with SLI. Furthermore, an investigation by a team of geneticists into the distributions of the FOXP2 gene across a range of animal and human populations revealed that the most likely scenario is that the gene has been the target of selection during recent human evolution (Enard et al. 2002). Language and social cognition Many investigators now consider that the last and perhaps most significant steps in the evolution of language – in particular the development of complex syntax – were cultural rather than biological, and focus their attention on the social and cultural environment in which language arose. According to these researchers, there was no specific biological adaptation for human language in the shape we find it today. Rather, we reached a stage of having a brain that was ready for language, before we had language. Language evolved in a cultural, not biological, setting. The emergence of language in human beings is thus in some ways comparable with the emergence of writing, which is known to have arisen in certain cultural settings and cannot be coded in the human genome. Michael Tomasello has proposed (1999, 2003b, 2008) that a crucial aspect of this was the emergence of a type of social cognition that enabled the development of human culture, and human symbolic communication within it. Crucial in this was the evolution of the ability to recognize other individuals as intentional agents with whom one can share attention. According 270 Linguistics to this ‘looky-look’ theory, the capacity for joint attention is crucial to the development of sharing of experience – and thus information – as well as collaborative action. Fully modern human languages developed, according to ‘looky-look’, via processes of grammaticalization (roughly, the emergence of grammatical elements from lexical elements – see §15.5) operating over periods of millennia on the grammatically less complex communicative systems that arose in the biological evolution of our species. Concluding remarks on language evolution It is fair to say that the majority viewpoint is currently tending towards the notion that our genetic make-up permits us to acquire language, rather than that language is genetically encoded. To use a computer analogy, our genes gave us the necessary biological hardware, but not the software, which emerged more recently, after the biological machinery was in place, in the human cultural context. Many investigators now situate the final steps in the evolution of language in human culture, in the interpersonal context. It is also widely accepted that unanalysable and independent symbols emerged first; syntax came much later. Although investigations of the communicative systems and abilities of animals does not unassailably support the gradual evolution of language from other communication systems, it cannot be doubted that the majority of fundamental biological components and processes involved in vocal production and perception are shared with animals. They are modifications of existing features, rather than entirely novel. Given this, it is difficult to disagree with those who hold that comparative investigation of non-human communicative systems is likely to provide a fruitful perspective on the evolution of human language. Another point of widespread (though not universal) consensus is that investigation of the evolution of language is not the prerogative of linguistics, but is best approached from many different disciplinary perspectives. We have mentioned anthropology, archaeology, psychology, genetics and neurobiology. Computer and mathematical modelling have recently come to promi- nence as means of testing theories, especially where multiple factors are involved. Summing up Many animal species have natural systems of communication employing bodily gestures and vocalizations to express emotional states, to warn conspecifics of dangers, to demarcate territorial boundaries, and for mating. These systems do not satisfy all of the design features of human languages. This does not mean that other animals are incapable of producing or comprehending human language, and many attempts have been made to teach human language to other species. The most successful have focused on apes. The systems apes have learnt show some of the design features of human languages, at least to some degree; duality of patterning and reflexivity are conspicuously absent, however. Studies of natural communication systems of animals and attempts to teach animals human language do not argue strongly either for or against the evolution of language from animal  Language in its Biological Context 271 communication systems. However, some cognitive mechanisms of language appear to have been in place prior to the evolution the modern humans. Speculations on the origins and diversification of human language can be traced back to mythology. The 19th century saw the emergence of many theories, including ‘bow-wow’, ‘ding- dong’, ‘pooh-pooh’, ‘yo-heave-ho’ and ‘la-la’. Recent years have seen the emergence of more sophisticated theories. According to ‘noddy’, language has its origins in gestures; ‘yackety-yack’ suggests that language emerged to facilitate gossip and is a replacement for manual grooming. ‘Just genes’ proposes that language is genetically encoded. According to one variant, ‘chatting- up’, language evolved by the normal evolutionary processes of natural selection; an alternative variant, ‘Oops’, maintains that language emerged as an accidental genetic mutation. Specific Language Impairment (SLI) is associated with a mutation of the FOXP2 gene, which was for a time heralded as the ‘language gene’. However, recent evidence indicates that neither SLI nor the FOXP2 gene are specific to language. A clutch of recent theories consider the final steps in the emergence of human language to have been cultural: biological evolution gave us a language-ready brain, but language arose in a socio- cultural setting. One such theory is ‘looky-look’, which argues that joint attention was the critical development. Guide to further reading Animal communication systems are surveyed in Bright (1984) and Morton and Page (1992). The communicative dances of honeybees are nicely described in Karl von Frisch’s 1973 Nobel lecture (Frisch 1992/1973, available online at http:// nobelprize.org/nobel_prizes/medicine/ laureates/1973/frisch-lecture.pdf). Vocal communication of birds is described in Kroodsma et al. (1982). Cheney and Seyfarth (1990) deals with communication systems of monkeys; nice examples of vervet monkey vocalizations can be found on the internet, at http://www.arkive. org/vervet/chlorocebus-pygerythrus/video-11a.html. Goodall (1986) treats chimpanzee commu- nication. Radick (2007) is a comprehensive discussion of investigations of the communication systems of primates and their scientific relevance. Attempts to teach language to chimpanzees are described in Hayes (1951); Gardner and Gardner (1971); Premack and Premack (1993); Savage-Rumbaugh and Lewin (1994); and Terrace (1979). For a critical overview see Seboek and Umiker-Seboek (1980). On the ‘Clever Hans’ effect, see Seboek and Rosenthal (1980). Genie’s acquisition of language is described in Curtiss (1977), and Curtiss et al. (1974) (reprinted in Lust and Foley 2004); see also Rymer (1994). For a brief survey of some of the main approaches to the evolution of human language see Carstairs-McCarthy (2001). Slightly older but still good overviews of the field from the perspective of linguistics are Aitchison (1996), and Chapter 2 of Foley (1997). The classic work dealing with biological aspects of language evolution is Lenneberg (1967); this book is now dated, and many of the ideas it presents have been challenged. Fitch (2000) is a more recent overview; also interesting is Lieberman (2000). Tomasello (2008) provides a readable account of his ideas on the social