Masters of the Planet

by Ian Tattersall

  Understandably, after 27 years without language, without symbols, this realization was also hugely traumatic. Schaller writes movingly of Ildefonso’s sense of grief as he perceived “the prison where he had existed alone, shut out of the human race.” Still, despite the fact that he subsequently had all of the language-learning difficulties and discouragements that every adult experiences, and much more to boot, he eventually learned to converse in ASL.

  Schaller’s experience with Ildefonso is as close as anyone in our time will ever come to witnessing what the birth of symbolic humanity must have been like, as an adventitiously prepared brain suddenly discovered what it was capable of. Schaller even believes that Ildefonso’s condition is more common than one might imagine, and that many people’s “intelligent, sane, yet languageless” state may be routinely mistaken by hearing or signing people for simple deafness with failure to sign. If this is indeed the case, maybe we have in Ildefonso at least a sideways glimpse into the prelinguistic human condition—albeit greatly modified by the loss of earlier systems of communication, and of the cognitive sequelae that went along with them.

  Unfortunately, Ildefonso was not of much help in determining what would it be like to be a normal Homo sapiens with everything except linguistic function. It eventually came to light that he had belonged to a small community of deaf and languageless individuals who communicated by miming, rather than by signing. Instead of describing their experiences concisely by stringing words together according to rules, they acted those experiences out, rather like guests at a dinner party playing charades. This was a hugely cumbersome way of communicating, so much so that once he had grasped the idea of language and had begun to compile an extensive vocabulary of signs, Ildefonso no longer had the patience to use it, and stopped spending time with his former associates. What’s more, he proved extremely reluctant to describe his inner life before he acquired language. There was perhaps no way in which he could have explained the difference; and in any event, he just didn’t want to publicly relive it. How and to what extent language is separate or different from what we experience as thought thus remains imponderable on the basis of this particular individual’s experience.

  This is a pity, because knowing the exact difference between mental processes with and without words is critical to understanding the cognitive difference between nonsymbolic and symbolic Homo sapiens. Those early nonsymbolic Levantine Homo sapiens got along perfectly well, living lifestyles that were much like those of the crafty and accomplished Neanderthals. And while their nonlinguistic state was limiting compared to our own, presumably they and their predecessors were not living in the oppressive cognitive darkness from which Ildefonso was so relieved to have escaped. They were perfectly fine, with lifestyles of a complexity that no organism before them had ever contrived to achieve.

  Perhaps we can catch an indirect glimpse of what being a prelinguistic Homo sapiens might have been like in the experience of Jill Bolte Taylor, a neuroanatomist who suffered a massive stroke that deprived her for several years of her linguistic capacity. At the age of 37 she lost her command of language, and as a consequence all her memories disappeared and she found herself able to live only in the present. On the other hand, she also felt a sense of peace, and of unaccustomed connectedness to the world around her. Her previous command of language had, it seemed, not only allowed her but compelled her to distance herself from her surroundings; and this, of course, is the essence of the human symbolic facility, which confers the capacity to objectify oneself and remain apart from one’s universe.

  Taylor’s experience, recounted after a full recovery, is a fascinating one. It’s nonetheless obvious that a cerebral accident in a speaking adult cannot precisely recreate the functioning of a normal prelinguistic human brain. But there may be another avenue by which we can envisage the nonlinguistic human state. Some psychologists have argued persuasively that young children who have not yet mastered their parents’ language do not think, at least in the way that adults do. And it’s possible that their mental manipulations of information may resemble those of prelinguistic Homo sapiens in some respects. Still, while it’s clear that children who aren’t yet talking don’t think like linguistic adults, their brains are of course immature (especially in the all-important prefrontal cortex, which matures notably late), and they can’t make all the connections between different kinds of information that adults do. What’s more, they cannot tell us articulately about their mental states, which they can only express through emotional acting out. And this brings us right back to the dilemma of understanding the chimpanzee that we encountered in the first paragraphs of this book.

  It is evident from the archaeological record that complex lifestyles, intuitive understanding, and mental clarity are all possible in hominids lacking language in its modern form. In the appropriate context, to be wordless is not to be dysfunctional. Nonetheless, words are a crucial enabling factor in complex cognition. The ability to manipulate words clearly expands and liberates the mind. The more words you have, the more complex a world you are able to visualize; and, on the other side of the coin, when you run out of words you run out of explicit concepts. Nevertheless, given that our language abilities seem to have been somehow grafted on to the earlier cognitive substrate possessed by the first anatomical Homo sapiens, our mental lives today are a constant tightrope-walk between the symbolic and the intuitive. Our symbolic abilities explain our possession of reason, while intuition, which is itself probably a curious amalgam of the rational and the emotional, accounts for our creativity. It is the fortuitous combination of the two that makes us the unstoppable if imperfect force in Nature that we are.

  The changeover of Homo sapiens from a nonsymbolic, nonlinguistic species to a symbolic, linguistic one is the most mind-boggling cognitive transformation that has ever happened to any organism. The details of this transition will probably forever evade us, and almost any scenario we might dream up risks trivializing it. But, with the examples of the Nicaraguan schoolchildren and Ildefonso in mind, perhaps it is not too hard to envision, at least in principle, how language might have emerged in a small community of biologically prepared early Homo sapiens somewhere in Africa. Indeed, I am greatly entertained by the notion that the first language was the invention of children, who are typically much more receptive to new ideas than adults are. They always have their own methods of doing things, and they communicate in ways that sometimes deliberately mystify their parents. For reasons that had nothing to do with language, the children concerned already had all of the peripheral anatomical equipment necessary to produce the full range of sounds demanded by modern languages. They must also have possessed both the biological substrate necessary to make the intellectual abstractions involved, and the innate urge to communicate in a complex manner. And almost certainly, they belonged to a society that already possessed an elaborate system of interindividual communication: one that employed vocalization as well as gesture and body language. After all, as in the case of every behavioral innovation, the necessary physical springboard had to have been there. And with the Nicaraguan example to hand it is easy to envision—at least in principle—how, once a vocabulary had been created, feedback among the various brain centers involved would have allowed the children to structure their language and thought processes simultaneously. For them, what psychologists have taken to calling “private speech” would have been a conduit to the conversion of intuitions into articulated notions that could then be manipulated symbolically.

  An additional attractive feature of language as the stimulus for abstract thought is that, unlike theory of mind, it is a communal possession. For the same reason that a poker player keeps his cards to himself, it would on the face of it seem to be actively disadvantageous for an individual to reveal to others his or her ability to read or accurately guess their minds. And while this reality would not obviate the spread of that ability within the population if it were merely one more expression of a generalized intelligence, in this
light it is hard to see theory of mind as in itself a driver of change. Of course, we are in total terra incognita here; and it may even be sheer speculation that language originated as a means of communication. (After all, in a typical human paradox, it is perhaps the greatest barrier to communication that there is in the world today.) It is conceivable that the functionally important role of language as an interior conduit to thought was paramount from the beginning. But language as a means of communication would most easily and rapidly have spread through a population that possessed the necessary biology—and ultimately beyond that small original population, throughout a biologically predisposed species whose newfound intellect soon allowed it to take over the world.

  LANGUAGE, SYMBOLS, AND BRAINS

  It would be much easier to speculate about what happened in that leap from nonsymbolic to symbolic if we had a better idea of how the human brain works: how it turns a mass of structured electrochemical signals into what we experience as our consciousnesses. Recently developed real-time techniques of imaging what happens in the brain (i.e., where it’s using energy) while it undertakes different cognitive tasks have taught us a great deal. But just how our controlling organ puts everything together into what we subjectively think and feel is still largely unknown. And this renders problematic the task of identifying those specific brain areas whose modification at the origin of our species laid the groundwork for our new cognitive performance. Nonetheless, any differences we might be able to detect between human brains and those of our close relatives would certainly give us somewhere to begin. And since paleoneurologists are still hazy about what differences in external brain shape between fossil hominids and humans mean, the natural place to start this endeavor is with the brains of living apes. After all, we have a broad idea about what we can do that the apes can’t—though it turns out that there are severe practical difficulties in getting an ape to do what you want inside a functional MRI machine. Which only serves to emphasize—yet again—the vastness of the cognitive gulf that separates us from them.

  We are, then, confined for the moment to static aspects of the brain in our search for the biological underpinnings of what makes us unique. And although it’s long been known that there are few if any gross aspects of the human brain without their counterparts in apes, significant differences in tissue architecture are beginning to emerge as neurobiologists look at ape and human brain materials in finer and finer resolution. One recent discovery is that, while apes and humans as a group are unique in having “spindle” neurons in parts of the brain that in humans are involved in complex emotions such as trust, empathy, and guilt, we have many more of them. Scientists aren’t yet sure exactly why this is, but one possible function for spindle neurons is in aiding high-speed conduction of impulses from these regions to an area at the front of the brain concerned with advance planning. It may be that the abundance of spindle neurons helps humans make swift responses to complex and changing social situations. As more and more findings such as this come to light, we will certainly be able to put together a more complete picture of what happens in human brains that doesn’t in others. But for the moment, while we can be confident that the behavioral advantage humans enjoy does not simply emanate from a greater mass of brain tissue, the best we can do is make educated guesses.

  My personal favorite conjecture is still the one made by the great Columbia neurobiologist Norman Geschwind back in the 1960s. Geschwind’s notion was that the discrete identification of objects—naming them—was the foundation of language. Using the connection I’m making here, it would also be the foundation of symbolic cognition. In Geschwind’s view, language was made possible by a physical ability to make direct associations between different areas of the brain’s cortex, without passing through the older emotional centers below. The cortex is the thin sheet of neural cells that covers the outside of the brain, and it has so greatly expanded during mammal evolution (and especially in us) that, as we’ve seen, it has become creased and folded to fit inside the confines of the cranial vault. The largest of the folds have been used to demarcate various major functional areas of the cortex, notably its frontal, parietal (upper side), temporal (lower side), and occipital (back) “lobes.” Within each lobe, other wrinkles demarcate major functional areas. Thus Broca’s area, that brain region which plays a key role in motor functions including control of the speech apparatus, lies within the left frontal lobe. Modern imaging techniques have shown that many motor and other functions are in fact widely distributed through the brain; but nonetheless the major control areas identified by the great nineteenth-century neurologists are still recognized today. And most modern neuroscientists are comfortable with the idea that the prefrontal cortex, right at the forward tip of the brain, is particularly crucial in the integration of information coming in from all over this hugely complex organ. It is clearly the seat of the higher “executive” functions, coordinating and regulating the activities of the phylogenetically older parts of the brain.

  But Geschwind’s particular candidate for the structure permitting the associations crucial in object-naming was the “angular gyrus,” a part of the parietal lobe that lies adjacent to both the temporal and the occipital areas, and is ideally positioned to mediate among all of these lobes. In humans the angular gyrus is large, whereas in all other primates it is small or missing altogether. What’s more, recent imaging studies have demonstrated that it is active in the comprehension of metaphors, which are emblematic of the kind of abstract connections that are basic to language. Whether Geschwind was right or wrong, it is thus frustrating that it is next to impossible to delineate the angular gyrus in endocasts of fossil hominid brains, so we simply don’t know at what point in our history it started to expand.

  In figuring out just what it is that makes our brains special, we always have to keep in mind that our controlling organ is a rather untidy structure that, from very simple beginnings, has accreted rather opportunistically over an enormous period of time. So perhaps we shouldn’t be looking for one single major “keystone” acquisition. Instead, the extraordinary properties of the human brain are likely emergent, resulting from a relatively tiny—and altogether accidental—addition or modification to a complex structure that was already, and exaptively, almost prepared for symbolic thought. A small tweak to an existing—and independently viable—structure gave rise to a new form of interaction among the brain’s constituents that gave it an entirely unprecedented level of complexity in function.

  If we can’t pinpoint any specific brain component as the basis for our modern human consciousness, we might ask about which cognitive systems might have been involved. One favorite system that has been getting a lot of play recently has been our working memory, the term used by psychologists to denote our ability to hold information in the conscious mind while undertaking practical tasks. Without substantial working memory it would be impossible for us to carry out any kind of operation that involved associating several different bits of information. Proponents of the idea that working memory most crucially underwrites our complex activities do not deny that ancient hominids also needed a certain amount of such memory; but they suggest that the difference between us and them, though substantial, is one of degree, related to increasing refinement of those executive functions of the prefrontal cortex that govern decision-making, goal forming, planning, and so on. As we’ve seen, the various technologies that hominids developed since the inventors of stone tool making first bashed one stone with another became more complex in a highly sporadic manner. And this has been taken as evidence that working memory increased in stepwise fashion, the last major step being taken somewhere between 90 and 50 thousand years ago.

  This scenario certainly fits with what the archaeological record seems to be telling us. But it still leaves the question open as to whether working memory is merely a necessary condition of our modern consciousness, rather than an altogether sufficient one. When we are pondering how we acquired our odd way of doing mental business,
we might do well to consider that identifying working memory as the key ingredient to our uniqueness may in fact be analogous to selecting thermoregulation, or distance vision, or object-carrying, as the key factor that caused the earliest hominid bipeds to stand upright. The reality is that once you have the capacity concerned you have bought an entire package of advantages, plus any disadvantages that might come along with it. In the case of bipedality, standing upright was almost certainly just what came naturally to the creatures involved. In the case of symbolic consciousness, it seems likely that a random modification of the already exapted brain, plus some children at play, led to the literal emergence of a phenomenon that changed the world.