Nick has other evidence of the earliest tool-makers that, he ventures, might again point to linguistic abilities. Specifically, he discovered that in the earliest archeological sites in Kenya, the tools were all made by right-handed individuals. This fact was revealed by the position of pebble cortex on the flakes. Because right-handers hold the core in their left hand and rotate it clockwise, the cortex, when present, will mostly be on the right edge of the flake. The opposite is true for left-handers. Although individual apes and other primates often have a handedness preference for manipulative tasks, as a species they are equally divided between right-handers and left-handers. Humans are unusual in having a population preference for one hand—90 percent of humans are right-handed. Handedness is associated with localization of function to the opposite brain hemisphere. The location of manipulative skills in the left hemispheres of (most) right-handers is accompanied by the location there of language skills, too. The right hemisphere has become specialized for spatial skills.
If it is true that language and manipulative skills evolved together, it seems likely that brain lateralization was part of that process. In that case, perhaps the Oldowan tool-makers, being preferentially right-handed, could have increased linguistic skills after all? The asymmetry of brain function is accompanied in modern humans by an asymmetry of shape: The left hemisphere is emphasized. This same asymmetry is seen in the earliest known crania of Homo habilis, the putative first tool-maker, but not in any austraiopithecine species. Nick sees this as further evidence of linguistic abilities in the Oldowan tool-makers.
Despite their differences of interpretation over the Oldowan evidence, Nick and Tom agree over the general significance of the next stage, the Acheulian. Unlike the simple core tools of the Oldowan, which may be formed by the removal of a very few flakes, the Acheulian handaxe involves extensive flaking and about fifteen minutes of effort. “Besides manifesting a clearer sense of spatial geometry [than in Oldowan tools], the technical sophistication of [handaxes] is such that even modern humans learning to make stone tools often require many months of apprenticeship to reach the requisite level of finesse,” observes Nick.8 This is evidence for cultural norms, he suggests, and a greater language ability than in the Oldowan tool-makers.
Tom sees “something humanlike in this product of Homo erectus minds,”9 referring to the handaxe. “Artifacts such as these indicate that the shape of the final product was a concern of the knapper and that we can use this intention as a tiny window into the mind of Homo erectus”10
These three lines of anatomical evidence—of the brain, the vocal apparatus, and the capacity for tool-use—provide the principal support for the notion of long, gradual changes on the road to language. Along with these changes in the brain and the vocal apparatus, there occurred concomitant gradual changes in the hand, changes that made it an increasingly suitable instrument for tool construction and use. As we saw in Chapter 8, Kanzi has difficulty flaking and using stone tools because of his elongated fingers, which cannot be fully straightened, his inflexible wrist, and his short and highly positioned thumb. While he can see how we hold the cobble and the hammerstone, and he can attempt to imitate our grip, he can never position the stones as effectively as we can for flaking.
Nonetheless, the coincident changes in the anatomy of the hand and wrist, and the increasing signs of tool construction and use in the fossil record have led many scholars to conclude that a common neurological structure undergirds both skills and that this structure is to be found only in Homo. To say that a common neurological substrate may exist still does not explain the nature of the driving force that was pressing brain expansion at such an unprecedented rate in all of mammalian development. Yes, Homo habilis was making simple tools and Australopithecus probably was not, but did Homo habilis require a brain that was 50 percent again larger than that of Australopithecus? Given Kanzi’s ability to flake stone, the answer obviously seems to be no. What then was pushing the brain to become larger?
It may be that actually making a tool is far simpler than having the foresight to know that a tool would be necessary in the future. Making a tool entails a great deal more than simply bashing stone together. In order to make a tool, one must have the right sort of stone at hand and one must not be engaged in another activity. In Kanzi’s case, these conditions are provided; we bring the rock and we focus his attention on the need for a tool by baiting the tool site. However, we were not around to help out Homo habilis. He had to plan ahead. He had to know that at some future time he would need a tool, even though he did not need it for a specific task at the time he found the proper stone or at the time he actually constructed the tool. Thus, the real cognitive demands placed on any tool-user entail finding the proper material, making the tool, and keeping the tool with him or her until it is needed. And all of this must happen without a stimulus, that is, without some immediately present set of circumstances that make the need for a tool manifest. If a tool-maker recognized that he needed a tool only when the occasion actually arose, it is likely that (1) there would be no appropriate stone around, and (2) by the time he made the tool, the situation leading to its need would have changed.
Consequently, it is not simply an understanding of geometry that a tool-maker must have; first and foremost the tool-maker must have the ability and the intelligence to plan ahead, to disjoin present behavior from future need. For this, the tool-maker must construct an elaborate mental model of the anticipated future. This model must include the tool and its purpose as well as the tool’s shape and the actions required to produce that shape. Once the tool is made, the maker must keep the tool in his or her possession until it is needed. This may seem simple, but when there are streams to be crossed, berries to be picked, predators to avoid, children to watch, and when the tool must be on hand at night as well, keeping this tool at ready access is not a trivial task. Only to the extent of anticipating future need, in the absence of any current reminder, will a hominid go to the trouble of carrying and keeping a single tool. Keeping a kit of such stone implements becomes even more difficult. Indeed, once the stone tool kit becomes larger than two or three implements, it is easy to see why temporary home bases, scattered throughout a range, would become necessary and convenient for storage.
Many animals, including apes, sea otters, and birds, use tools—but only apes and man make tools, and only man makes tools that he is not going to use in the immediate future. In addition, man carries tools long distances for days or weeks anticipating their future use. Man keeps tools with him, through daylight and darkness, through bad weather and good. Unlike other animals, man searches far and wide for good raw material from which to make his tools and then transports that material to other locations. All of these skills require considerable foresight and planning, skills attributed to the frontal lobes. They require constant orientation to the future and a clear understanding that present and future needs may not be the same. The greater the ability to plan ahead, anticipate future needs, and prepare for them, the greater the chance of survival for a creature who has small teeth and minimal means of natural defense.
One day Nick showed me a tape of some of the last surviving stone tool manufacturers, who live in a remote section of the New Guinea highlands. These men learned their skills as youths, before their people had experienced any contact with the outside world. It was clearly an activity they enjoyed and were quite proficient at. They talked and sang as they worked, sometimes hardly even watching their own handiwork, it was so second nature to them. The knowledge of how to construct the tools seemed to reside in their hands rather than in their head. Their heads were busy spinning tales of past and future occasions where tools had been and would be needed.
The 50 percent jump in brain size between Australopithecus and Homo habilis seems to reflect the increased need to plan ahead that makes stone tool production possible. As man began to plan further and further ahead, he surely constructed increasingly elaborate mental models of what might happen in the
future. At some point, he inevitably began to construct multiple models, each with different plausible scenarios and each requiring a different sort of preparation. At that point, man could no longer coordinate his behavior effectively with glances, gestures, emotions, and common knowledge of the situation. To coordinate and select between different mental models of the future, man needed language. With language he could describe his model of the anticipated future to others. This holding in mind, and contrasting of multiple models, must have required an increase in cortical capacity. However, the actual making of the tools and even the syntactical and phonemic skills used to describe the various mental models are, and probably were, rather automatized and once acquired, needed little additional cranial space. Potential mental models of the future are not the kinds of ideas that readily become automatized. They tend to remain in conscious awareness and to be constantly updated by the events at hand.
Somewhere between five hundred thousand and fifty thousand years ago, a hominid species became human, as Homo erectus gave way to Homo sapiens. At first these Homo sapiens were archaic in form, but by one hundred thousand years ago, they began to merge into the form we know today. During the same time, technology progressed from the simplest manufacture and use of stone flakes and cores to the production of elaborate implements that required a clear mental concept, or template, and considerable manual dexterity. Ultimately, some tools took on an aesthetic appearance, too, in the form of beautifully fashioned and decorated implements made of stone, bone, and antler. About thirty thousand years ago, during the period archeologists call the Upper Paleolithic, artistic expression became manifested, in the form of body ornamentation, images painted and engraved on walls, and the carving of bone and ivory figures. Compared with archeological evidence of human behavior earlier than thirty thousand years ago, the advent of the Upper Paleolithic was a dramatic and explosive event, and it included the practice of elaborate rituals, the establishment of larger communities, and the development of long-range contacts, possibly involving trade. Methods of hunting became much more efficient, and people began to settle in the far reaches of the world, including Australia and the Americas. Revolution is not too strong a word to describe the magnitude and rate of change that took place.
There is no doubt that the nature of human behavior we see in the Upper Paleolithic was an expression of the modern human mind. However, there is currently little agreement as to degree to whether these behavioral changes were biologically or culturally driven. The puzzle archeologists face is this: If anatomically modern humans evolved a hundred thousand years ago, why did modern human behavior not appear until some seventy thousand years later? The fact that no obvious anatomical change corresponded to what can only be called the dawn of cultural life has led many to ponder the place of language in this set of events.
Was it language that made all of this possible? Iain Davidson certainly thought so, and he was the first to have had the patience to explain the cultural explosion in such detail to me that I began to grasp the full weight of its importance.
To Iain, Homo erectus had barely even taken the first step on the journey toward modern human behavior, let alone progressed some distance on it. “We propose that all human ancestors without language should be considered as closer to chimpanzees than to modern humans in their behavior,” Iain wrote in a paper he co-authored with William Noble for the Cascais conference volume. “Two events in the record of prehistoric evolution of human behavior can be said to be the first that unambiguously entail the existence of language: the colonization of Australia, before 40,000 years ago, by people crossing the sea to an unknown shore; and the appearance of sculptures and bas reliefs with coded symbols in different parts of Europe before 32,000 years ago.”11
Iain and his colleague have developed a hypothesis that argues that before our ancestors created images, not only did they not have language, but they could not have had language. They acknowledge that the art of Upper Paleolithic Europe betrays the existence of full-blown symbolic language, and suggest that earlier, more primitive image-making activities must have preceded it. These earlier stages would have marked the emergence of the referential abilities that characterize image making and symbolic language. True language evolved sixty thousand years ago, or perhaps a little earlier, suggests Iain. Prior to that, our ancestors’ vocal skills were mere “context specific communications.”12
Iain and Bill’s argument is twofold. First, it dismisses the suggestion that the Acheulian handaxe implies intentionality on the part of the tool-maker and therefore the inferences of cognitive and linguistic skills that go with it. They claim, instead, that the characteristic shape of the handaxe is the incidental outcome of removing many flakes from a particularly large core, not the deliberate fashioning of a shape according to a mental template. And the consistency of shape through space and time is the result of “a small number of learned motor actions,”13 not the systematic imposition of arbitrary form. They point out that the sticks made by chimpanzees to catch termites conform to local regularity, and that this conformity should be interpreted as a consequence of the chimps having a small repertoire of actions for preparing the tool.
“If handaxes were produced according to a mental template, that would indeed imply considerable intentionality,” Iain observes. “The hominid would be sitting there for fully ten or fifteen minutes, working steadily toward a planned goal, and that is not a trivial intellectual exercise. But the paradox of the archeological record is that there is absolutely no other evidence of this putative level of intentionality. If that competence were present, you would see evidence of it,” concludes Iain.14
Although Nick Toth concedes that Iain has a good point, he rejects the notion that Acheulian handaxes are the byproducts of repetitive flaking. “It makes no sense to me,” he says. “If you do what he says, you finish up with a discoidal core, not a tear-drop shaped handaxe.”15
When Iain was visiting the Language Research Center early in 1993, I thought I would perform a small test of his hypothesis, and so challenged him to produce a handaxe by knocking flakes off a large core. He had to be guided only by the need to remove flakes efficiently, I charged, and must not intentionally produce the characteristic shape of the Acheulian axe. He failed. Perhaps the test was unfair, because flaking is a considerable skill in itself, and Iain was not fully adept at it. My view is that Iain is probably wrong on this point, and that Homo erectus stone knappers knew what they were aiming for when they made handaxes.
The second line of argument in Iain and Bill’s hypothesis relates to the nature of language itself. The essence of symbolic language is its referential nature, the act of invoking through the use of symbols an event or object in its absence. Words come to replace, or refer to, those actions or objects in the minds of speaker and listener. The ability to displace reference to an object from the presence of the object itself was engendered by the act of using images, Iain and Bill argue. The scenario is something like the following.
An individual points to a bison and perhaps vocalizes but, critically, makes a simple iconic image in the soil or on a wall, perhaps reflecting the curve of the head and back. Later, that same image invokes the notion of bison, but in the absence of the animal; and so might the associated vocalization. The crucial mediator in the process, insist Iain and Bill, is the production of the visual image that separates the object from a reference to it. “Depiction … provokes the reflectivity that in turn permits referential utterance,” they wrote in a scientific paper.16 “Communication is common to many creatures, but only humans have the capacity to communicate their meanings independent of context.”17
If Iain is correct and language as we know it appeared on the scene only forty thousand years ago, this means that large-brained Homo sapiens existed on this planet for nearly sixty thousand years without language. It means that in the forty thousand years since we invented language we have come to depend on it so completely that we now believe it to be innate. It also me
ans that Homo erectus, Homo habilis, and Australopithecus could not have had anything like language. I finally began to see why it was that Iain was wary of the data I had assembled on Kanzi. I also began to wonder what it could have been like to be a member of a human group in which people communicated by nonverbal expressions and gestures, but did not use language. If Iain is correct, what were we like before we invented language? I thought of those vague references to “dreamtime” people in aboriginal cultures, and the references in our own culture to the absence of “knowledge of good and evil” before Eve consumed the proverbial apple. I also recalled those references to some African and Indian cultures in which it is said that older brother and younger brother decided upon different paths long ago when they first became aware that it was possible to control fire. It is said that the older brother elected to remain in the forest, following the old ways and eschewing fire and language. The apes of today are descended from older brother. Younger brother went out from the forest and kept fire with him, becoming the progenitor of all humans today. Could cultural myths such as these hark back to a murky time in our distant past when we possessed human minds but no language?
Though I greatly admired Iain’s work, it was difficult to accept his view that language was a recent visitor on the evolutionary playing field. If this were true, how could Kanzi understand complex, novel sentences like, “Can you go scare Matata with the snake?” I knew my data were sound. Iain had a similar confidence in his data. Moreover, we each respected the care and critical eye that the other brought to the process of reconstructing the roots that undergird human existence. Could such diverse perspectives meet?
Kanzi: The Ape at the Brink of the Human Mind Page 28