How then did the faculty of language come to colonise the human brain? ‘There must have been a series of steps leading from no language at all to language as we now find it,’ writes the linguist Steven Pinker, ‘each step small enough to have been produced by random mutation [of genes] and with each intermediate grammar being useful to its possessor.’ It is, of course, possible to imagine how language might have evolved in this way from a simpler form of communication or ‘protolanguage’, starting perhaps with gestures, moving on to simple words or phrases with a single meaning, with the rules for linking words into sentences coming later. Pinker’s intended parallel between the means by which our species acquired language and the infant’s rapid progress from burbling through words to sentences might seem plausible, in the way of all evolutionary explanations, and would indeed be reasonable if language simply ‘facilitated the exchange of information’. But, as Chomsky pointed out so persuasively, language is also an autonomous, independent set of rules and meanings that impose order, make sense of the world ‘out there’. Rules and meanings cannot evolve from the simple to the complex, they just ‘are’. The structure of sentences is either meaningful or meaningless. The naming of an object is either ‘right’ or ‘wrong’. An elephant is an elephant, and not an anteater. Hence Chomsky insisted, against Pinker, that those seeking a scientific explanation for language could, if they so wished, describe it as having evolved ‘so long as they realise that there is no substance for this assertion, that it amounts to nothing more than a belief.’ This, of course, is no trivial controversy, for language is so intimately caught up in every aspect of ‘being human’ that to concede that it falls outside the conventional rubric of evolutionary explanation would be to concede that so does man.
The dispute over the evolutionary (or otherwise) origin of language remained irresoluble till the late 1980s, when the first PET scans revealed how the simplest of linguistic tasks involves vast tracts of the brain in a way that defies any simple scientific explanation. Here every mode of language, thinking about words, reading and speaking them, is represented in different parts. The prosaic task of associating the word ‘chair’ with ‘sit’ generates a blizzard of electrical activity across the whole surface of the brain. Further, those scanning investigations revealed how, in the twinkling of a second that it takes to speak or hear a word, the brain fragments it into its constituent parts through four distinct modules concerned with spelling, sound (phonology), meaning (semantics) and articulation. These ‘modules’ are in turn then further subdivided ad (virtually) infinitum. The perception of sound, for example discriminating between the consonants ‘P’ and ‘B’, is represented in twenty-two sites scattered throughout the brain. There is something absolutely awe-inspiring in supposing we understand a word like ‘elephant’ only after it has been parsed in this way. And then, to compound it all, the brain must simultaneously while ‘parsing’ elephant also comprehend its meaning in its entirety, for the constituent symbols can really only be understood within the context of the whole word.
It is one thing to try to work out how the brain processes a single word (and that is baffling enough), quite another to extrapolate from such findings to try to imagine the same processes as they apply to a sentence, with its structure of ‘subject-verb-object’ and numerous subsidiary clauses. Move into the real world, with its ceaseless conversation, and the problem becomes insuperable. What sort of brain processes, one might ask, must be involved when a group of football fans convening in the pub before a match discuss their team’s prospects for the coming season – drawing on a vast storehouse of knowledge and judgement of the form of previous seasons, the strengths and weaknesses of their players, and assessments of the performance of their rivals. How do they pluck from the storehouse of their memories the right words, or conjure from the rules of syntax and grammar the correct sequence with which emphatically to argue their opinion? How does the electrical firing of the neurons in their brains represent words and capture the nuance of their meanings?
And so? ‘Language flows so readily, that it is easy to assume it must be simple.’ But language only appears simple because it has to be so. There would, after all, be little point in humans acquiring this novel and powerful mode of inserting their thoughts directly into the minds of others if it took many years to get the hang of, and was difficult to use. But that apparent simplicity is, as already noted, a mark of language’s profundity, concealing the inscrutable complexities of brain function that make it appear to be so.
The major legacy of linguistics and neuroscience in the past few decades has been to reveal the complexities concealed behind that apparent simplicity while drawing attention at the same time to how the faculty of language requires major changes in every aspect of the functioning of the brain: a massive increase in its memory capacity so as to be able to store that vocabulary of forty thousand words, together with the provision for their near-instant recall; a profound deepening of the mind’s emotional repertoire with its feelings of sympathy and affection; the powers of reason; the moral distinction between right and wrong; and the imaginative intelligence with which poets and writers express themselves in unique ways.
The opportunity to reflect further on such matters will come later, but for the moment we must briefly return to contrast the conventional evolutionary portrayal of the origins of that ‘totally unprecedented entity’ Cromagnon man with how, in the light of the above, they now appear to be. To be sure, that steadily expanding brain over the preceding several million years, with its much enhanced neuronal firepower predisposed to those higher intellectual attributes, particularly language, and thus that cultural explosion of technical innovations and artistic expression. But that much-expanded brain by itself does not explain the phenomenon of language, nor why the evidence for its undoubted ‘benefit’ of being able to think, act and make sense of the world should have emerged so late and so suddenly. Why did the brain continue to expand in size for those millions of years when the ‘pay-off’ was so slight, and the attendant hazards of obstructed labour and dependent offspring so large? And this conundrum becomes yet more puzzling now we know that language is not just some bolt-on addition to the primate brain, but occupies large areas of it, and required the massive extension of those other attributes of mind, such as memory and intelligence, on which it depends.
Here neither of the two proposed evolutionary scenarios – that language evolved ‘early’ or ‘late’ – is convincing. The proponents of the ‘early’ scenario infer (quite rightly) that it must have taken millions of years for so complex a system to have evolved – all the way back to Turkana Boy’s people, Homo erectus, and beyond. Why then, one might ask, did he exhibit so little evidence of the ‘culture’ that language makes possible? The ‘late’ theorists claim language to be unique to Homo sapiens, the spark that lit the cultural explosion that separates him from his nearest relatives – but that would presuppose that it evolved over the mere 100,000 years since his emergence from Africa. This dispute cannot be resolved, but it serves the useful purpose of drawing attention to our profound ignorance: we no longer have the vaguest inkling of what caused the ‘switch to be thrown’ to inaugurate that first and most astonishing of all civilisations. Thirty-five thousand years on, we humans can draw on a vast treasure house of the cumulative knowledge and technology of the many civilisations that have had their moment in the sun, the Egyptians, Greeks, Romans, Arabs and so on. The genius of the Cromagnons, with their passion for art and wittily decorated spear-throwers, is that they had to work it all out for themselves.
This then is the riddle of the Ascent of Man: how and why twenty or more distinct species of hominid should, over a period of several million years, have undergone that wholescale anatomical