Now, it is important to avoid giving the wrong impression. Erectus was not the equal of Homo sapiens. In fact, compared to sapiens they had many, many shortcomings. It is important to discuss a few of the ways erectus, for all their relative brilliance, were inferior to sapiens.
First, their speech may not have carried over long distances. This is a result of their inability to form the same range of vowels that sapiens can produce, in all likelihood their vowels would have been hard to pick up across distances. On the other hand, like the Pirahãs and other groups, it is possible that erectus was able to overcome this shortcoming by simple yelling combined with distinctive pitch patterns. In either case, the fact that their speech would have not carried far doesn’t mean that they did not have language.
Erectus speech perhaps sounded more garbled relative to that of sapiens, making it harder to hear the differences between words. This could have entailed less efficient communication than modern humans enjoy, but it would not mean that they lacked language. The existence of ambiguity, homonyms, confusion and the importance of context to interpret what someone has said to someone else continues to be crucial to modern speech. Part of the reason for erectus’s probably mushy speech is that they lacked a modern hyoid (Greek for ‘U-shaped’) bone, the small bone in the pharynx that anchors the larynx. The muscles that connect the hyoid to the larynx use their hyoid anchor to raise and lower the larynx and produce a wider variety of speech sounds. The hyoid bone of erectus was shaped more like the hyoid bones of the other great apes and had not yet taken on the shape of sapiens’ and neanderthalensis’ hyoids (these two being virtually identical). The non-modern erectus hyoid bone has profound implications for the evolution of speech and language, as will be seen.
These were not the only differences between erectus and other Homo species. Erectus faces were more distinguished by prognathism than modern humans’, which would have impeded speech as we know it (though prognathism would not have blocked their speech).
Behind these physical differences were genetic differences between erectus and sapiens. The FOXP2 gene, though it is not a gene for language, has important consequences for human cognition and control of the muscles used in speech. This gene seems to have evolved in humans since the time of erectus. FOXP2 gives greater speech control. Possessing a more primitive FOXP2 gene, erectus would have had less laryngeal and therefore less emotional control in their speech. FOXP2 also elongates neurons and makes cognition faster and more effective. Without this erectus would certainly have been ‘duller’ than modern humans. But this is not a surprise.
Such a FOXP2 difference could have resulted in a lack of parallel processing of language by erectus, another reason they would have thought more slowly. FOXP2 in modern humans also increases length and synaptic plasticity of the basal ganglia, aiding motor learning and performance of complex tasks.
It is also unclear therefore whether erectus enjoyed the same degree of cognitive plasticity as we do. It is probable that erectus was a dull, non-inventive creature compared to modern humans. That doesn’t mean that it was a languageless creature. As we have already seen, erectus was at the time the smartest entity ever to have lived. Just not as smart as sapiens turned out to be. The difference in intelligence might have been great or it might have been less than their brain size would indicate. There is much here that we do not know.
Supporting the idea of a less well-developed intellect for erectus, its most common tools were more similar in some respects to the tools of earlier, non-Homo primates. Erectus’s simplest tools may have been more homogeneous and non-combinatory (not built from multiple parts – handless axes vs axes with handles, for example). On the other hand, the earliest evidence for complex tools predates sapiens. These were hafted spears and were created by Homo erectus (or one of its descendants if a finer splitting of Homo species is preferred). And, of course, there are also the water craft that erectus used to cross significant distances in the ocean, which can only be classified as complex tools. Thus the archaeological record, while showing no complex stone tools, provides indirect evidence that erectus did in fact make complex tools of other materials.
To repeat, theories based on stone tools often omit evidence from non-stone tools. Palaeoanthropologist John Shea argues for a tight connection between technology and language, explaining that they are structured similarly in certain ways, though basing his work nearly exclusively on stone tools. This is understandable to a degree, of course, because stone tools are the only tools still available for direct study. And it may very well be true that if erectus had simpler technology then they would also have had a simpler language. This is not at all clear, however. Looking exclusively at stone tools is insufficient. It does not follow that simpler tools imply a lack of language or even a qualitatively different kind of language. Some palaeoanthropologists appear to conflate complex toolmaking with complex syntax, by not being fully aware of the enormous variation among modern languages in this regard – some with complex etymological tools but syntax that is less complex perhaps than those tools would suggest.
Culture and biology together explain the apparent absence of ongoing extensive brain evolution among Homo sapiens. Sapiens seem to have passed a threshold of complexity that allows them to take care of themselves so well that they simply no longer have the same need for evolutionary assistance as they once did. As already discussed, this could come from different life histories in sapiens, cumulative cultural knowledge, language developed over time and differently powered brains. Modern humans live, survive and produce viable offspring because of culture.
This is not to say that there is no microevolution going on in modern humans. There could be humans with brains that are different from those of other humans in ways that produce greater numbers of viable offspring. But there is no evidence that brains are becoming larger or more specialised across sapiens either currently or since the beginning of this species. Neither is there a claim that sapiens brains could not evolve to someday make humans incomparably smarter than humans are today. One can imagine creatures with much higher intelligence on average than Homo sapiens. But evolution is not trying to build a brainiac. It is concerned merely with building a creature that is just good enough to have viable offspring.
And there is another thing. The only way natural selection can make people smarter is if more intelligent people have more offspring that live. But culture changes everything. Across the globe, cultures care for their members more effectively than at any time in human history. Cultural welfare has come to vie with physical evolutionary pressures in the definition of humans’ evolutionary niche. Culture has also created a niche that is no longer purely biological, altering the course of evolution, as new cultural pressures arise and traditional biological pressures become comparatively less significant. Individuals who would have perhaps failed to survive without the level of cultural support available to modern humans are now able to transmit their genes to viable offspring. It may be that physically weaker or congenitally infirm individuals have no evolutionary disadvantage in the environment of a nurturing culture. This is good for humans, because cultural niches change, which favours increased diversity in the species, spawning ever more nurturing cultures, accelerating the change and survivability of those who at one time may not have survived. Eugenics advocated the improvement of human genetic heritage, but by failing to recognise the power of culture in shaping our evolution, eugenics had it wrong. Culture not only is the key to improving the species and the survivability of all, but also has liberated us from the strictly biological.
Humans arrived at this place of cortical stability through changes that might surprise some. They responded creatively and culturally to challenges of safety, travel, climate, shelter and food. As we learned earlier, they learned to cook food, which in turn helped them to eat more meat, which helped to shrink their guts. Repeating, then, calories that were once used for digestion were then freed up for Homo’s brains.
The result
is modern brains and bodies, improved human thinking, morality and emotional control. This evolutionary progression reveals as clearly as anything the interrelatedness of organs and the embodiment of the brain in the body as a holistic apparatus. Human brains are smarter when our intestines are smaller. From erectus to sapiens, humans are in a sense self-made, pulling themselves along both the evolutionary and linguistic trails by their bootstraps. Erectus began the long process for humans of thinking their way to the modern world.
Looking back on the course of human brain and cultural evolution there are major discoveries, accelerated cultural evolution and long periods of stagnation among early humans.
Following the rise of Homo sapiens, profound innovations appear, along with a much faster rate of cultural change. This is why it is appropriate to refer to the Homo sapiens era, relative to that of other Homo species, as the ‘Age of Innovation’. The innovation of Homo sapiens, greater than that of any other species, increased exponentially with the beginning of agricultural economies around 10,000 years ago on (arguably) opposite sides of the globe, in both Sumeria and Guatemala. Even before the rise of agriculture, however, innovations seemed to occur after species reached both cerebral and cultural thresholds. But an ‘Age’, whether of invention, imitation, or iron tools, does not characterise its entire population. In the Iron Age, people still used wooden tools, and in our present Age of Innovation, most Homo sapiens do not innovate in any significant way.
To learn about the brains of humans and how they underwrite language from several sources, one must turn to neurology, palaeoneurology, archaeology, linguistics and anthropology. One must learn through clinical and neuroscientific studies of neurodiversity, from people with disorders such as specific language impairment (SLI), aphasia, or autistic spectrum disorder (ASD). And humans need to compare their brains with those of earlier great apes.
As erectus learned first, no brain is an island. Human brains are networked. First, their brains are networked in their bodies, connected evolutionarily and physiologically to other organs. But, equally importantly, their brains are networked to other brains. As philosopher Andy Clark has claimed for years, culture ‘supersizes’ our brains. A brain is an organ connected to other brain organs in the sea of culture. This is a point worth emphasising. In fact, one cannot understand the role of the brain in language and evolution without this conception. It is why caution must be exercised before accepting the popular but very misleading idea that the brain is a computer, an artefact very unlike an organ. Indeed, computers lack culture.
The question to ask rather is how do the anatomy, functioning and overall architecture of the brain help us to understand the role of the brain in the body, one organ among many? And how does culture help us to understand the brain as part of a social network of brains? And finally, the $64,000 question for our purposes: what does a brain have to be like for its owner to have language? The best conclusion is that the brain is a general-purpose organ evolved for fast and flexible thinking. It has to be prepared for anything. And for that very reason it is freer of instincts or any other form of prespecified knowledge than other species’.
Humans are fortunate that natural selection widened rather than narrowed their cognitive options. This freedom illumines our use and possession of natural language and other advanced cognitive abilities. However, when we lose any of that freedom, through different cognitive or speech disorders, the nature of our brains is revealed more clearly. This is why it is necessary to examine carefully breakdowns of the ability to engage in normal linguistic activity. Language deficits such as these might interfere with normal participation in a conversation, composing or understanding sentences, or being able to use the right words in the right context. Surprisingly, what emerges from such study is that there is little evidence that human brains have genetically specialised tissue for language. This perhaps startling assertion is supported by the fact that there is no convincing evidence to date that there are specifically heritable linguistic deficits. Language deficits are rooted in other physical or mental problems.
This may come as a surprise, although it would be perhaps more unexpected to learn that there was tissue or neuronal networks specialised for language, since language results from human neuroplasticity, which is in part the ability of neurons to change to better fit the needs of their containing organism. And there is, of course, also synaptic plasticity – the ability of connections (synapses) between neurons to alter as humans learn, grow, or suffer brain damage.
And not just humans. It has been discovered that if the third digit of an owl monkey is amputated (a gruesome experimentation that I hope will be halted), then changes happen in the brain of the monkey. The brain of the owl monkey has distinct areas for each digit. Following amputation, the area associated with the amputated digit will be overrun by other brain functions. In other words, the owl monkey’s brain is flexible. Human brains are even more so. Brains don’t let perfectly good neurons stand idle if they are needed for something else. Like Arnold Schwarzenegger in The Terminator, human brains rewire around damaged areas and repurpose undamaged areas that are no longer needed for their original functions.
Human brains also undergo a tremendous amount of synaptic change during a lifetime. Brains literally change – adding more connections, thus more white matter,† in response to learning – to adapt to new cultural environments or pathology, such as brain damage. Synaptic pruning and the establishment of novel synaptic connections in the brain are particularly robust features of human brain development before puberty, leading to the naming of this period of human development and learning as the ‘critical period’. It isn’t clear whether this stage is as crucial in theories of cognition (such as language learning) as is sometimes claimed, but it is certainly an important segment of human cognitive development and neural plasticity.
As mentioned earlier, the brain is not a computer. It is important to underscore this again in the present context because it is a core belief for many linguists, cognitive scientists and computer scientists. The desire to see the brain as a machine goes all the way back to Galileo’s analogy of the universe as a clock.
The appeal of this analogy is obvious, since both a computer and a brain handle information. But conceiving of a biological organ, whether a brain or a heart, as a computer, is an impediment to understanding either. To take one example, the brain does not appear to be organised into separate modules (or working units) for different functions in the way computers are. Additionally, the brain evolved without intervention. It is biological. A common reply to this is that it doesn’t matter what the computer is made of, only what it does and how it does it. And yet the biological stuff from which the brain is made cannot live apart from its interaction with biological tissue and liquids that link it as part of a system with its vital non-computational functions (such as love). One could build a computer from human neurons but it still would not be a brain. Unlike a computer it does matter what a brain is built of and where it is housed. Now one might reply that a computer is also part of a network, plugged into a power grid and connected to other computers and so on. But neurology is ultimately not the same kind of thing as electronics. Computers lack biological functions, emotions and culture.
Another difference is that computers do nothing unless they are running a program. While brains do not literally have software, there are those who attribute something like software, a ‘bioprogram’, to account for language learning. But that metaphor has failed to produce answers to the kinds of questions and facts encountered in the story of human evolution. There is just no source of conceptual content inborn in all humans. Concepts are never inborn, they are learned.‡ As Aristotle put it, paraphrased by Aquinas, ‘Nihil est in intellectu quod non sit prius in sensu’ – nothing is in the intellect that was not first in the senses.
On the other hand, perceptual abilities (seeing, hearing, feeling, tasting and certain emotions such as fear) do seem to be inborn. This kind of innate physica
l predisposition is drawn upon in language acquisition and cultural evolution. Some people use vision more than hearing when gathering data. Humans’ emotional need for one another and desire for social interaction favour the development of language. So the brain definitely has specific, individual properties. But it is still important to avoid conceiving of the brain as a blastula of specific conceptual regions or a computer or pre-programmed with actual knowledge about anything.
One of the reasons that some creatures skipped the handout of brains from the evolutionary deity is energy consumption. Brains are calorifically expensive. The average human brain burns around 325–350 calories per day. That is about one-fourth of the average human’s daily calorie consumption at rest (1,300) and about one-eighth of the average active person’s requirement of around 2,400 calories per day. In other words, the brain is a high-maintenance piece of equipment. As specialists on the evolution of human fat consumption have observed:
Compared to other primates and mammals of our size, humans allocate a much larger share of their daily energy budget to ‘feed their brains’. The disproportionately large allocation of our energy budget to brain metabolism has important implications for our dietary needs. To accommodate the high energy demands of our large brains, humans consume diets that are of much higher quality (i.e., more dense in energy and fat) than those of our primate kin … On average, we consume higher levels of dietary fat than other primates, and much higher levels of key long-chain polyunsaturated fatty acids (LC-PUFAs) that are critical to brain development.2
Beyond calorie consumption, another reason to lack a brain is redundancy. Parasites can live in human guts without needing to think, ingesting whatever comes their way because of the brain-guided decisions of their hosts. They don’t need brains because they use ours. Why waste resources? A final reason for lacking a brain is the absence of the correct evolutionary history. For humans this history was more complicated than for any other animal. Human brains, bodies and cultures have all evolved over the past 2 million years in a grand symbiosis. The body (including the brain) is connected to culture as hummingbirds are to flower pollination. Human bodies and brains are enhanced by culture, just as culture itself is enhanced by our thinking and language. Ever since Franz Boas, one of the founding figures of North American anthropology, it has been known that culture can affect body size, the use of language, what we recognise as ‘talent’, along with other aspects of human phenotypes. As noted in chapter 1, dual inheritance theory, also known as the Baldwin effect, refers to the discovery that culture indirectly affects the genotype itself. Natural selection favours changes in our alleles that produce culturally desirable components of our phenotypes.
How Language Began Page 14