The Emergence and Nature of Human Consciousness, Part Two: The Rise and History of Consciousness
Now that we have a general understanding of consciousness, and an even clearer picture of what we do not understand and what we cannot put into words, we need to examine how humans came to possess this capacity. The prehistoric origins of consciousness can be understood approximately, but not with any certainty. As I have said before, it is probable that the expansion of consciousness from the earliest humans to present day humans followed the expansion and elaboration of the human brain, particularly the neocortex. The physical expansion of the brain, coupled with an increase in the brain’s neuronal complexity, made possible an expansion of social interaction, which established a feedback loop. Those who could interact most effectively tended to have a survival and reproductive advantage over others, reinforcing those genetic, anatomical, and physiological features that had conferred this social advantage. So we must assume that a modern Homo sapiens sapiens has a richer, more complex internal experience than any previous species within our genus. This has brought with it immense possibilities, not all of them beneficial by any means.
Working from these general ideas,
how can we be more specific about the rise of consciousness? We're going to
address this issue by focusing on the following:
2. The anatomical and genetic factors that
favored the rise of mind.
3. The way in which degrees of consciousness are shared by
certain other animals, and what this tells us about the evolution of
consciousness.
4. The
evolutionary advantages of being conscious.
5. The
attempt to trace the rise of consciousness through an examination of prehistoric
artifacts and the earliest artistic expressions.
6. The
roles of social interaction and interaction with the environment in the rise of
consciousness.
7. Those periods of prehistory in which there appear to have
been major expansions of human consciousness.
Sentience and Awareness
Researcher Nicholas Humphrey points out the significance of an animal's ability to detect the physical boundary between itself and the outside world. This ability allows the animal to differentiate between what might be called me and not me. The surface of an animal is where energy-matter exchanges occur. Natural selection therefore favored the ability to sense these exchanges, so that the animal could detect whether such exchanges were harmful or beneficial to it. This sensitivity evolved from simple reactivity to "more sophisticated types of sensitivity". As Humphrey puts it,
To begin with, sensitivity and responsivity were intimately linked. And so in some ways they always have been and still are...But as animals became increasingly sophisticated at attuning their behavior to the environmental situation, the sensory side and the response side of the process must have become partially decoupled. Before long a central site evolved, where representations—in the form of action patterns—were held in abeyance before they were put into effect. Thus action patterns had become action plans, and representations had become relatively abstract. The place where they were held in store could be said to be the place where they were held in mind.1
The rise of mind is therefore, according to Humphrey, associated with the rise of "meaningful phenomena". Events began existing for someone. Therefore, in his view, if we are searching for the deep origins of mind and consciousness, we must begin with the ability to feel, and why that was necessary.
Another researcher has postulated that consciousness came about by the evolution of the capacity for awareness. It is his hypothesis that during the Cambrian "Explosion" (see Volume One, pp. 250-251) animals evolved the ability to distinguish between more vital and less vital incoming sensory information. Given the density of such information, priority had to be given to those signals that were most crucial to the animal's survival. The capacity of animals to focus on and process such signals led, in his view, to the evolution of attention. In his words, "Attention is a data-handling method, the brain’s way of rationing its processing resources...Mammals and birds both have it, and they diverged from a common ancestor about 350 million years ago, so attention is probably at least that old." He has labeled this idea the attention schema theory. In his words,
It has a very simple idea at its heart: that consciousness is a schematic model of one’s state of attention. Early in evolution, perhaps hundreds of millions of years ago, brains evolved a specific set of computations to construct that model. At that point, ‘I am aware of X’ entered their repertoire of possible computations.
From this basic capacity, he says, awareness in the animal brain evolved new forms, gaining new abilities and evolving the capacity to integrate elements of information in increasingly sophisticated ways. Such a capacity would make it possible to construct models of phenomena detected by an animal's sensory apparatus. It would also help an evolutionarily advanced animal detect patterns and assess the relationship of the external world to the self. In humans, this capacity would make it possible to judge (or make a guess about) the internal thoughts and feelings of other humans. The ability to see others as possessors of awareness is crucial to such a judgment. It is, in this perspective, the foundation of social interaction.
In short, therefore, a sense of their own awareness allowed animals, at some as yet undetermined point in prehistory, to attribute awareness to other animals. We perceive others of our kind as consciously aware, and this helps govern the nature of our interaction. We even sometimes attribute awareness to animals or objects that don't possess it.2
Two researchers examining the origins of consciousness have looked into the rise of vertebrates, which they date to some time before 520 million ybp. They hypothesize that the first sense of which animals were aware was vision. Brains, they believe, arose as vision was connected to other forms of sensory input that were made possible by the evolution of specialized embryonic structures. In their words, "primitive reflexive systems [became] image forming brains that map and perceive the external world and the body's interior." From an anatomical standpoint they hypothesize that a forebrain, midbrain, and hindbrain were necessary, but not necessarily a fully developed cerebral cortex. They believe that the first true brains also required a network of hierarchically organized nuclei that were of similar shape, nuclei which intercommunicated to help integrate sensory input into representations. They also contend that a reticular formation was required that also helped integrate sensory input and helped create "attention, awareness, and neural synchronization".3
These researchers believe that the optic tectum was the original point of conscious perception. This is the case with fish and amphibians. They also believe the center of conscious perception then shifted, in birds, reptiles, and mammals, to the dorsal pallium or, eventually, the cerebral cortex of it. The genes associated with the structures that make consciousness possible are, apparently, universal in all vertebrates.4 (It should be noted that these researchers use the term consciousness very broadly, hypothesizing that it may be many millions of years older than is commonly assumed.)
Genetic Duplications and Anatomical Development
Delving further into the genetic underpinnings of consciousness, we can broaden the examination we made in the chapters on the brain's evolution (pp. 498-535). We should recall the phenomenon of duplication, in which, in its most extreme form, a complete copy of a genome can be passed down to an offspring by each parent instead of one half from each parent. Individual chromosomes or genes can be duplicated as well. And while these duplications are usually a disaster or at the least a disadvantage, occasionally duplications are fortuitous. A duplication [perhaps partial] around 400 million years ago appears to have been involved in the rise of color perception in the vertebrates. A second duplication, around 35 million ybp, facilitated the rise of true trichromatic vision in the primate line.5 We should also recall the evolution of Hox genes, to which we referred in Volume One. As we saw, early in the vertebrate line there was an animal that possessed four copies of the Hox gene instead of just one, and this had enormous consequences. The evolution of the head and the rudiments of what ultimately became the mammalian brain were two of these consequences. From the basic template of the vertebrate brain, as we saw, more specialized structures arose and a "division of labor" in the brain came about. The balance between the frontal cortex and the hippocampus is governed by the gene Emx2, for example.6 All of this came about by evolutionary processes, which repurposed existing structures for new uses relentlessly. As one specialist expresses it,
The ingredients—and genes—that make up our brains are, like the ingredients that make up the rest of our bodies, the product of evolution. New cognitive systems are patchworks and modifications of old. Specialized biological structures need not be, and perhaps never are, made up entirely, or even in large part, of wholly novel materials.7
If this is the case, if consciousness began to emerge out of the animal kingdom many millions of years ago, if genetic, anatomical, and physiological factors helped give rise to it, we could expect to see evidence of it in other highly evolved species, and in fact we do. Bearing this in mind, what other species have manifested behaviors that may be conscious in nature?
Intelligence and Possible Consciousness in Other Animals
As we examine the different
levels of intelligence among the various members of the animal kingdom, we
immediately note that greater intelligence allows an animal to possess a more
diverse behavioral repertoire. In recent decades, many researchers have come to
realize that there are non-human animals that display such high levels of
behavioral sophistication that we may infer they possess some sort of
rudimentary consciousness.
So, with this in mind, let's examine those animals that may possess such consciousness. We'll start with the non-primates, to provide ourselves with a broader perspective, and then examine our closest relatives, the chimpanzees, look briefly at the gorillas, and then make some general observations
Cetaceans
The members of the mammalian
order Cetacea—the whales, dolphins, and porpoises—have been studied by
specialists for many years. The first members of Cetacea evolved over 50
million ybp. These animals are intriguing to consciousness researchers for
several reasons. The ratio of brain size to body weight of some Cetacean
species, particularly certain dolphins, is intriguingly high, although not in
the range of members of the genus Homo.8
The behaviors exhibited by cetaceans are sometimes extraordinary, and hint at conscious awareness. A team of researchers studying dolphins in the wild (and summarizing a broad range of research) finds that dolphins live in social groups, groups characterized by complex relationships and alliances. Their behavior within groups indicates significant capacities for learning and memory. Dolphins have exhibited social cooperation and role taking as well. Dolphins have also demonstrated cultural learning. They can teach other dolphins distinct dialects and methods of foraging. Several species of whale have also demonstrated cultural abilities, and have even exhibited social hierarchies. These capacities appear to be the product of the expansion of the neocortex in the cetacean line. Although the evolutionary path of this neocortical expansion differed from that of the primates, the researchers examining their intelligence found
...many cetaceans evince some of the most sophisticated cognitive abilities among all mammals and exhibit striking cognitive convergences with primates, including humans. In many ways, it is because of the evolution of similar levels of cognitive complexity via an alternative neuroanatomical path that comparative studies of cetacean brains and primate brains are so interesting. They are examples of convergent evolution of function largely in response, it appears, to similar societal demands.9
Other researchers have detected evidence of cultural learning in cetaceans, with the bottlenose dolphin being particularly noteworthy in that regard. They also note teaching and imitation among orcas (killer whales). As they express it, "[t]he complex and stable vocal and behavioural cultures of sympatric groups of killer whales (Orcinus orca) appear to have no parallel outside humans, and represent an independent evolution of cultural faculties."10 Research also reveals that several regions of the cetacean prefrontal cortex are similar to those associated with certain advanced cognitive functions in primates. Such functions include, according to this research, "attention, judgment, intuition, and social awareness". In laboratory settings bottlenose dolphins have shown the ability to understand symbols, manipulate objects, understand the behavior of other animals, and understand their own image. They have also shown the ability to mimic both sounds and actions. Bottlenose dolphins can even grasp certain aspects of syntax in communication. Their overall ability to imitate what they perceive is nothing short of remarkable. These abilities rest on their excellent capacities for remembering, learning, and innovating.11
Cephalopods
The class of mollusks known as Cephalopoda includes the octopuses, squid, cuttlefish, the chambered nautilus, and related species. Its first members evolved about 488 million ybp.12 Within this class the octopuses are of particular interest. Research conducted both in the wild and in controlled settings shows that octopuses display extensive exploratory behaviors, the ability to recognize objects in a variety of viewing conditions such as changes in light (perceptual constancies), and skill at navigation. The arms of octopuses have a great many neurons, and are capable of independent action (to a degree). The central brain of the octopus plays the largest part in directing its behavior, but sometimes the central brain acts more as an observer of action than an initiator of it.13 Octopuses typically have about 500 million neurons, as opposed to 100 billion for a human. They are not quick learners, but given time they are capable of learning some surprising tricks, including figuring out mazes, unscrewing jars from the inside (!), and escaping from aquariums. They also seem to have the ability to tell one human from another. They have even exhibited play activity.14
The evolution of the cephalopod nervous system proceeded down a path different from that of the vertebrates, but cephalopods still have some notable similarities to them. Their eyes have a similar ability to focus images on the retina. They can learn through reward and punishment, and by testing whether something works or not. Octopuses seem to have both short and long-term memory. They also appear to sleep. Cuttlefish, from the same class, even exhibit REM sleep, which may indicate the ability to dream.15
Some researchers looking into why octopuses evolved their surprising level of intelligence have concluded that cephalopods, who tend to live short life spans and reach sexual maturity quickly, lost their external shells during their evolutionary development. This loss increased the predatory pressure they were under, but it also allowed them to explore environmental niches they never would have been able to otherwise. It was this combination of factors, they believe, which led to the evolution of cephalopod intelligence. They concluded that "the evolution of intelligence might not be constrained to a single evolutionary route".16
Corvids
The members of the bird family Corvidae—the ravens, crows, jays, and other, similar birds—demonstrate mental acuity of an extraordinary variety. Their apparent intellectual prowess is surprising, given their size, but there is significant evidence documenting their abilities. Magpies appear to recognize themselves in mirrors.17 (Self-recognition in mirrors is considered a crucial test of mental awareness by most researchers.) Rooks have figured out how to make water in a pitcher rise by putting stones in the jar until the water is within reach.18 New Caledonian crows have shown remarkable tool-making ability, demonstrating the ability to fashion hooks out of wire in order to reach food, and to repeat this behavior.19 Scrub jays have the ability to remember not just where they have stored food but when they have done so.20 Scrub jays may even have imagination. These and other abilities have led some researchers to declare that certain corvids are not only intellectually superior to other birds (with the possible exception of parrots), but they are the equals to some of the non-human primates.21
What could account for these abilities? Corvid encephalization is one possible factor. Crows, for example, have an encephalization quotient of around 4.1, just about equal to chimpanzees and approximately half that of humans (if we use an EQ for humans on the high side of the estimate). Birds in general have high neuronal density, fitting many more neurons into a given space than primates. Researchers have also noted that corvids lack the frontal cortex characteristic of primates. They have therefore concluded that corvids followed a different evolutionary path toward acquiring brains capable of problem-solving. Birds have a brain region known as the nidopallium caudolaterale, which appears to carry out the kind of goal-directed tasks that in primates are carried out by the prefrontal cortex.22
The Great Apes and Other Non-human Primates
So now we turn to the issue of consciousness in our closest biological relatives. Studies of non-human primate intelligence have been conducted for many decades, and the results of these studies have often stirred controversy, especially when they involve such issues as whether the great apes possess a genuine capacity for language. From an evolutionary standpoint our closest relative is the chimpanzee, which, as we saw in Volume One, diverged from our line somewhere between 5 million and 7 million years ago, although this divergence may not have been fully completed until about 4 million years ago. The gorillas are our next closest relatives. It has been postulated that their line diverged from ours about 8 million ybp, but recent evidence shows that such divergence may have happened 10 million or 11 million ybp (although this has not yet been confirmed).23
What do we know about the intelligence of chimpanzees and gorillas? No researcher has ever surpassed Jane Goodall in first-hand observation of and research on chimpanzees. During her observations of chimpanzees in Tanzania she witnessed many examples of learned, repeated behavior, problem-solving, hierarchy formation, tool-using, and tool making. She also observed chimps using stones and small branches as weapons during fights. Her conclusion about this is striking:
The chimpanzee, with his capacity for primitive reasoning, exhibits a type of intelligence more like that of man than does any other mammal living today. The brain of the modern chimpanzee is probably not too dissimilar to the brain that so many millions of years ago directed the behavior of the first ape men.24
Research on the nature of chimpanzee intelligence indicates that it may be largely genetic in its basis. The biologists examining this issue found that many chimpanzee cognitive traits are heritable, while environmental factors seem to play less of a role in them.25 Further, chimpanzees have shown the ability to delay gratification, and the ability to do so is closely correlated with intelligence.26 Other indications of chimpanzee intelligence are such measures as the ability of chimpanzees to recognize themselves in mirrors (in one study, up to 75% of subjects aged 8-15, although this ability appears to decline with age)27, the apparent ability of chimpanzees to use sign language (see below), and the surprising ability of young chimpanzees to recall numerals from their working memory.28
The most controversial investigations of chimpanzee intelligence involve experiments to see if chimpanzees possess linguistic abilities. Arguments about this issue very often center around the definition of language itself, and no universally accepted definition exists as yet. Since most (but not all) researchers agree that the structure of the chimpanzee larynx and tongue are not well-suited for producing speech, experiments with chimpanzees (and gorillas) have concentrated on the ability of chimpanzees to use the hand symbols of sign language. The criteria for language (discussed briefly in Volume One) include, but are not necessarily limited to, the use of symbols to consciously communicate information from one user to another (or several others), the arrangement of symbols in a particular order, an order that is critical to the actual communication itself, and the use of symbols which stand for or describe aspects of the real or imagined world. (The word information here is used in the broadest sense.) Does the communication taught to chimpanzees meet these criteria? Are the chimpanzees employing syntax in the manipulation of symbols? More crucially, are the chimpanzees communicating meaning or are they engaged in simple imitation? The results of experiments are mixed. While there was one research project that taught a chimpanzee (Washoe) about 250 signs, with which the chimpanzee was able to make very simple sentences, a prolonged experiment with another chimpanzee (Nim) failed to prove genuine linguistic ability. Kanzi, a bonobo [close relative of the chimpanzee], uses lexigrams and knows about 400 symbols, which he is reportedly able to use in a grammatical way.29
Gorillas, as we noted above, are our closest genetic relatives after chimpanzees. There has been notable research done on their language capabilities. The most well-known research involved a gorilla named Koko, who died in 2018. Koko indeed did learn many signing symbols, but her facility in them has been questioned by many observers, who point out that her keepers often prompted her. The consensus on the question of chimpanzee and gorilla speech seems to be moving toward the opinion that our primate relatives are not engaging in true linguistic activity but rather are demonstrating behavior based on receiving rewards and affection. And there is scant evidence that the simians involved in this research are attempting to teach such signs to others of their species.
But does all this mean that apes (and other non-human animals) lack the ability to engage in cultural teaching and learning? Not at all. Key studies released in 2013 indicate the ability of both whales and monkeys to learn from the experience of others, and even acquire skills from them.30 And in 2014, evidence that suggests chimpanzees may engage in the transmission of culture was revealed:
For decades, scientists have known that chimpanzee troops are often distinct from one another in the wild, possessing collections of behaviors that seem to form unique cultures. Researchers suggest that nearly 40 chimp behaviors are socially acquired, most of which involve various forms of tool use, such as wielding hammers and pestles. But the learned behaviors also include courtship rituals such as leaf-clipping, where leaves are clipped noisily with the teeth; social behaviors such as overhead hand-clasping during mutual grooming; and methods for eradicating parasites by either stabbing or squashing them.31
The larger question that arises from these experiments and those on primate cognition in general is, do chimpanzees and gorillas possess consciousness in some form? Once again turning to the question of language use, a group of researchers that has been deeply involved in non-human primate language experiments is adamant on this point. Arguing that language facility such as that exhibited by Kanzi can create conscious awareness, they state:
Our experience with great apes convinces us that they in fact possess consciousness, for they have first “person” accounts to offer of their lives…We emphasize the power of cultural forces upon the neural substrate of biology and the significant role of culture as a force in evolution.32
But as we have already noted, there are researchers who dispute the contention that any non-human animal possesses the ability to communicate in language. Two researchers who have studied communication in depth describe language as a combinatorial system, one in which signals are combinations of other signals. Such systems, they contend, naturally arise out of non-communicative behaviors, and can only develop into complex systems in animals with sufficiently advanced cognitive abilities. Humans, they say, have outstripped the limits on combinatorial communication that constrain other animals because they are capable of ostensive communication, meaning they can demonstrate things in a distinct manner.33
Two philosophers concerned with the concept of the theory of mind−the ability to make reasonable guesses about the mental state of another animal−contend that while certain non-human animals do indeed possess significant problem-solving skills and demonstrable intelligence, they do not have the capacity to make inferences about the internal state of others.
The available evidence suggests that chimpanzees, corvids and all other non-human animals only form representations and reason about observable features, relations and states of affairs from their own cognitive perspective. We know of no evidence that non-human animals are capable of representing or reasoning about unobservable features, relations, causes or states of affairs or of construing information from the cognitive perspective of another agent.34
However, other researchers point to the anatomical similarities between the brains of humans and non-human primates, and they point out that similarities in the processing of visual images in humans and non-human primates may be part of the substrate of conscious awareness. They argue that the question of whether non-human primates possess what we would call genuine consciousness is one that needs much more research before a definitive answer can be given.35
In my view, it could be argued that the human possession of language is unique in the animal kingdom and that therefore humans are uniquely conscious. And yet, consciousness may not necessarily require language. Do chimpanzees and gorillas possess a sense of self? Mirror recognition experiments hint that they might. Do they possess a skill set of a kind associated with conscious beings? The ability to fashion tools, teach skills to others, and to use a wide variety of signals to not only communicate but form social hierarchies suggest they might. This consciousness is certainly not of the depth and fullness of human consciousness, but perhaps it is real nonetheless.
So, what can we conclude from this brief examination of intelligence and (possible) consciousness in non-human animals?
First, there are multiple routes to intelligence, self-awareness, and at least some level of conscious functioning. Cetaceans, cephalopods, and corvids all show surprising abilities, even cultural learning, and yet none of them reached these points in the same way primates did. This reinforces the notion that consciousness is an emergent feature of life itself. It is something of which living energy-matter is capable. It arises out of explicable, flesh and blood phenomena. Evolution's mindless processes are capable of tremendous innovation, as natural selection, faced with a variety of environmental challenges, can blindly "manufacture" the mental ability of an animal to meet these challenges.
Psychologist Merlin Donald has put it this way:
There is no doubt that the context in which consciousness came into existence is an overwhelmingly material one. If we know little else about its origins with certainty, we must concede that consciousness is an aspect of complex life...Since we already know that complex life evolved from inert matter, it follows that consciousness also evolved from inert matter. This is Emergentism, an approach that is inherently credible because consciousness is, in every known instance, both alive and embodied and therefore an aspect of the natural world.36
We can even say that since consciousness has a physical origin, there is no reason to believe that beings on other planets, to whom we refer as aliens, cannot possess consciousness if they have some sort of sufficiently evolved and complex brain. If they possess consciousness, there is every reason to believe they are capable of possessing culture, and if they are very highly evolved, it is entirely possible that their culture can bring forth what we call civilization. Therefore, enormous possibilities, ones we may not have fully considered, arise out of the fact that consciousness has a physical basis.
Second, the split between human ancestors and the animals that led to chimpanzees, the last great bifurcation of the African ape lineage, was of crucial significance. The human line acquired, as we saw in the chapters on the human brain’s evolution, all of the biological capacities that made our consciousness possible. The chimpanzees, with a much more restricted area of radiation and apparently lacking the fortuitous genetic inheritances that allowed the human brain to excel, offer a faint but still discernible echo of our earliest ancestors’ capacities. They have primate vision, primate hands, primate agility, and a brain structured along primate lines. They are able to communicate a great many things to each other, and to form social groups. They have very low but still real technical skills. They can learn many things, and teach these things to each other. They exhibit friendship, kinship ties, love, rage, curiosity, and violence. They have survived in a world that has driven many other species into extinction.
Yet, their ability to control the environment in which they live is severely restricted. They have been vastly outstripped in intellectual power and ability by their closest cousins. And the gifted cetacean line, lacking the prehensile hands humans possess, never built a technical society and all that such a society is capable of creating−including superior minds. Humans possessed an unbeatable combination of physical features that ultimately made the genus Homo what it is today. The advanced consciousness that evolved in our line was a naturally occurring phenomenon of the highest order. Other animals may be self-aware and may have an interior world. But humans don’t just have an interior world. As one writer put it, they have an interior universe.
Is Consciousness an Evolutionary Advantage?
Since the “objectives” of a species are its own survival and perpetuation, can it be argued that consciousness is an evolutionary advantage? It can, of course, be pointed out that many non-conscious animals have enjoyed tremendous reproductive success. Strictly speaking, therefore, consciousness is not a requirement for survival in the animal kingdom. But this doesn’t mean that the possession of consciousness provides no reproductive benefit. For example, no species within the primate order is as numerous as we are. Humans, in fact, are thought to outnumber all other primate populations in the world combined, and by orders of magnitude. If we were to look at another metric, geographical distribution, no species of primate comes anywhere near the range of human habitation. For that matter, no large animal of any kind approaches the human range of settlement. So it would seem as if human intelligence and human consciousness confer an advantage. What is the exact nature of this advantage?
In the previous chapter we saw that a nervous system’s ability to assess, at a high level, the signals coming into it is a fundamental aspect of consciousness. The human ability to assess a situation and, if necessary, adjust one’s behavior accordingly, has been crucial to our survival. Many other animals can assess a situation. But none of them can do so at the human level. Consciousness provides this edge. One researcher characterizes this ability as the flexible response mechanism, the human ability to gather information and concentrate on the information most relevant to the task at hand.37 It can also be said that the human ability to innovate, imagine, and to organize human efforts are crucial elements of human success. These abilities rest on conscious thought.
Further, I would contend that the use of language by humans, and the human capacity to describe perceived aspects of the exterior world, or the human’s interior world, to other humans, argues persuasively in favor of the adaptational benefit of consciousness. The ability to communicate in language is a powerful advantage, and it is this ability that is the foundation of our advanced culture. All of these elements−situation assessment, inventiveness, imagination, organization, advanced modes of communication−are the product of the highly evolved human brain, and are coincident with the possession of mind.
Some neurologists emphasize the fact that the mind is a biological “accident”, unplanned, non-designed, the product of a brain that was haphazardly constructed, a phenomenon that was, basically, a side effect of the brain’s anatomy and physiology. But in my view, this wouldn’t negate its efficacy in its role of promoting reproductive success. It may have been an accident, but from our standpoint, it was a fortuitous one, at least in part.
But consciousness, and the larger mind of which it is a part, are also the basis of much of human suffering, irrationality, violence, and cruelty. As we have seen before, many researchers hypothesize that the psychological torments to which humans are subject are the product of the mind’s complexity and the incomplete (or even totally absent) understanding of one’s self. Further, fear, hatred, and tribalism paired with linguistic and organizational abilities can have horrifying consequences. Human consciousness can conceive of both heaven and hell. Bringing the latter of those two to life has been an all too common aspect of human society. And if humans dominate the surface of this planet now, it is our inability to control the unforeseen consequences that emanate from our consciousness that is most likely to be our downfall.
Cognitive Archaeology
An intriguing approach to the study of consciousness and its emergence in our genus, albeit one open to various interpretations, involves what is called cognitive archaeology. This an attempt to infer the level of our ancestors' mental abilities and learning capacities through an analysis of the cultural artifacts they left behind. The earliest such artifacts were, of course, the first human-made tools (or tools produced by hominids in the transitional era from australopithecines to recognizably human specimens).
A tool may be understood simply, and most broadly, as an object external to the human body that can be used to help perform a task of some sort. We must imagine that the very earliest tool use simply involved grabbing something from the immediate environment such as a branch or a rock and using it to augment an animal’s efforts. But even as simple of an act as that was significant. It implied that the animal saw a connection between the rock or branch and the accomplishment of the task at hand. The animal perceived that the task couldn’t be done only through the use of its own body. The use of an object grabbed from nature to modify another object also implies that the animal understood something about the object it wished to modify. The animal evaluated the object it wished to modify. The rock or branch seemed suitable to the task of modifying it. None of this was verbalized, but it was understood nonetheless.
The thought process at work here can be expressed simply: this object can do that thing. In the first understanding of this lay a revolution. Doubtless there was a great deal of trial and error in the first use of stones and pieces of wood to do work. There must have been a great deal of experimenting. But through this process, a relationship was being established among hand, eye, and brain. The truly great breakthrough came when animals began modifying objects to do work. The modifying of tools involves capacities and skills such as imagination, foresight, dexterity, the evaluation of materials, and an even deeper understanding of the job to be done. Tools helped train the mind, and, as we saw in Volume One, a synergy was established within the best tool makers: better brains made better tools. Better tools helped guarantee the survival of the brains that had created them.
The evolution of the prefrontal cortex may have been the key development driving tool manufacture and elaboration among primates. Research indicates that both the prefrontal and parietal cortices are implicated in human tool manufacture, and that even the oldest tool tradition, the Oldowan, dating back to the early Paleolithic era, indicated tool-making abilities that are uniquely human in nature.38
The first modified tools were,
naturally, very crude. There were significant improvements made in the
manufacture of stone tools, of course, but technological progress in the
prehistoric world was often excruciatingly slow. An example of this is the Acheulean
(or Acheulian) tradition. (See Volume One, pp. 343-346, for a fuller discussion
of this tool-making tradition.) It was named for the town of Saint-Acheul,
France, near which the first examples were discovered. As we have seen
previously, Acheulean tools were essentially bi-facial stone hand axes and
closely related tools. Carved from rock cores, the earliest known example of
this type of tool dates back to 1.7 million ybp.39 Acheulean tools
have been found not only in Africa, their place of origin, but in Europe and
Asia as well. (They appear to exhibit regional variations.) And variations on
this tradition were still being used as recently as 200,000 ybp. So an entire
class of tools existed for 1,500,000 years. This is three hundred times
longer than the period from the first true cities in Mesopotamia to the present
day. (And there are some sources which say Acheulean tools were being used as
recently as 100,000 ybp.) What accounts for this extraordinarily long period of
use? And did this represent technical stagnation? One expert responds in this
way:
The Acheulean technocomplex, though expansive in both time and space, represents a dynamic period in human evolutionary history. In this time period, australopithecines went extinct, genus Homo flourished, hominins reached the edges of the world (but hadn't quite made it to the Americas), cognitive capacity increased, meat-eating and cooking behavior picked up, and the handaxe tradition traveled from East Africa to Europe and India. There remain important questions regarding the possible cognitive or cultural underpinnings to the morphology of Acheulean tools, or absence thereof, as well as questions of their distribution and use. Whether or not the Acheulean technologies were static, the time period in which they were made and used was assuredly eventful. As a result, the better we understand the Acheulean, the better resolution we'll have for understanding a critical period in our evolution.40
There were, of course, other types of tools, such as hunting weapons, that were devised during this period, but the persistence of the Acheulean was remarkable. As we will see in one of the next sections of this chapter, there was a tremendous technological acceleration (at least relative to earlier periods) once Homo sapiens had become firmly established.
Another way of trying to infer our ancestors’ mentalities is through an examination of impressions in rock walls, cave paintings, and three-dimensional art objects. We will examine the development of human art more fully later, but we can say here that the earliest pieces of human art so far discovered are cupules (cup-shaped impressions pounded into a rock surface). Those located in Auditorium Cave, which is part of the Bhimbetka complex, in the central Indian state of Madhya Pradesh, are perhaps the oldest ones. Such cupules have been found on several continents, but those in India are perhaps more than 200,000 years old.41
Figurines discovered in Europe date back as far as 35,000 ybp (the one discovered in the Hohle Fels Cave in Germany) while a variety of “Venus figurines” have been dated between 23,000 and 25,000 years. These figurines are fascinating in themselves, and there is debate about their meaning and significance.42 Even older examples of three-dimensional art have been discovered in the Blombos Cave in South Africa. (See Volume One, p. 355.) They are sea shells that have been perforated, and which were apparently used as beads. Recent research indicates that these artifacts may be 75,000 years old. (We will discuss their significance in the study of human cognition below.)43
But for many people the most spectacular prehistoric art consists of the cave paintings found in various locations in the world. In 2018 research revealed that cave paintings discovered in Spain were more than 64,000 years old, and that they were created by Neanderthals. (See Volume One, pp. 376-378 for a discussion of the Neanderthals.) Remarkably, researchers working in a cave in southeastern Spain, Cueva de los Aviones, discovered perforated shell beads and pigments estimated to be 115,000 years old, also Neanderthal in origin.
The authors [of the study describing Neanderthal art] argue that, despite their oafish reputations in pop culture, Neanderthals were the cognitive equals of [modern] Homo sapiens. If their results hold, the finds imply that the smarts underpinning symbolic art may date back to the common ancestor of Homo sapiens and Neanderthals, some 500,000 years ago.
“Neanderthals appear to have had a cultural competence that was shared by modern humans,” says John Hawks, a paleoanthropologist at the University of Wisconsin-Madison who wasn't involved with the study. “They were not dumb brutes, they were recognizably human.”44
Research on the age of Neanderthal artistic expression reveals that it predated that of modern humans in Europe by more than 20,000 years. It also reveals other remarkable finds, such as a hand stencil dated at 66.7 thousand years minimum. The scientists conducting this research conclude that the images they have examined are part of a longer tradition, one perhaps lasting more than 25,000 years. Moreover, it suggests that other cave art discovered in Europe may be of Neanderthal origin, and that we may discover Neanderthal art in Africa and Asia as well.45
Many other important examples of cave art, both in the form of paintings and sculptures, have been found. Notable locations are Lascaux, Chauvet, and Niaux in France46; Altamira, El Castillo, and Tito Bustillo in Spain47; and Lubang Jeriji Saléh cave in Borneo, Indonesia48, among others. All of these sites are associated with anatomically modern humans
The earliest known pigment used by prehistoric artists was ochre, which is derived from iron-rich clay. Archaeological research indicates that this substance, which is primarily either yellowish or reddish, was used perhaps as long ago as 250,000 ybp.49 Other research, less firmly established, reveals that possible grinding tools, marked by ochre stains, have been found at a site called GnJh-15, in Kenya. These possible tools have been found in layers dated from 284,000 to 500,000 years in age.50 Ochre has been found in many other sites as well, most notably Blombos Cave. Researchers believe it was used not just in cave paintings but for bodily decoration. It should be noted that many researchers believe the very oldest forms of artistic expression are body painting and adornment. So it is possible−possible−that humans living in east Africa were doing this as early as a half million years ago.
So what does all this tell us about the emergence of modern consciousness? First, it can be said that in creating art (or tools for that matter) humans were displaying imagination, the ability to see things in the mind’s eye, however imperfectly, that do not exist. Artistic expression and tool making both center around the desire to give imagined ideas some sort of concrete form. We must suppose that talented individuals were inspired to copy or elaborate upon such expressions.
Second, both artistic expression and tool-making taught humans (if only unconsciously) that all tasks are divided into sub-tasks, the number of such sub-tasks rising as the complexity of the overall task increases. In performing such tasks, humans were learning to behave in more systematic ways. (We must imagine that hunting may have taught humans similar systematic thinking.)
Third, tool making (and in my view, the creation of aesthetically satisfying art) relies on what has been called deliberate practice. This deliberate practice is made possible by conscious awareness. While there are skills that can be acquired unconsciously, research demonstrates that when motor and mental skills have to be combined, this can only be done effectively by conscious beings. Deliberate practice involves concentration. It requires an evaluation of one’s skills in comparison to an ideal level, consistent effort to improve, and being flexible enough to master new skills. A researcher in the field of prehistoric technology points out that Acheulean hand axes are not easy tools to make, requiring an extensive set of very specific skills and, in his words, “physical strength, fine motor control, and sheer bravery.” Injuries, often very serious, must have been common. And yet, the genus Homo, the only genus capable of deliberate practice, mastered the hand axe. With deliberate practice came skill-based hierarchies, and perhaps even a rise in social status for the most capable tool makers.51
Fourth, artistic expression indicates the development of an aesthetic sense, and such an aesthetic sense would eventually be expressed in tool making as well. Although different cultures were ultimately to produce vastly different styles of art, there were certain consistencies in all of them, elements that appealed to the sapiens brain. We will examine such elements closely in the next section of this volume.
Perhaps most significantly, the creation of such objects as beads or other forms of adornment represented the ability to think symbolically. (See Volume One, pp. 383-387 for a discussion of symbolism and language.) Two researchers have characterized the significance of such adornment in this way:
Examples of symbol use by early Homo sapiens include the use of syntactic (complex) language and the production of material culture that carried symbolic meaning. The production of things that carry meaning is frequently referred to as “symbolic material culture”. Examples include the first jewellery and abstract engravings.
A symbolically mediated culture is one in which individuals understand that artefacts are imbued with meaning and that these meanings are construed by and dependent on collectively shared beliefs. This criterion is crucial. It explains how human norms and conventions differ from the ritualised behaviours found in nonhuman primates.
In simple terms this means that people were able to use the artefacts that they made to organise (mediate) their social world in much the same way as we do today. Within each group of people artefacts may have had meanings that were understood only within that group. An example is the design of a bead necklace which may have carried a specific meaning that was not understood by people who were not a part of that group.52
While tool making preceded the evolution of Homo sapiens by many millennia, it was the evolution of the sapiens brain, encountering and building on older traditions, that drove technology into unimaginable places, as we will see. And while art probably has its origins in the human desire to self-decorate, it truly arose (as far as we know) when Homo sapiens neanderthalensis evolved. When Homo sapiens sapiens came to dominate the human genome, artistic expression began to expand both in diversity and geographic extent. The rise of technology and art were two of the most momentous events in human history, and these responses to the world—and expressions of the self—were to have vast and unforeseen consequences.
In short, the development of tools and art both reflected and encouraged the brain’s development. All of this took place in an environmental and social context. It is to this context that we turn next.
The Natural Environment and Social Interaction as Factors in the Rise of Consciousness
Evolution, as we have seen, is driven by the interaction of genetics and environmental change. In considering the evolution of human consciousness, we need to consider what factors in the natural environment encouraged the intelligence which, as we have noted above, was an evolutionary advantage for humans. The natural environment has always imposed a variety of selection pressures on the upright primates that evolved in the great arc between eastern and southern Africa. Climate is one of the most important of those pressures. In Volume One, (pp. 315-316) you may recall we noted the change in the world’s climate in the late Miocene Epoch, about 8 million years ago, and the concomitant possible reduction of forested areas in Africa. I hypothesized that this change may have influenced the evolution of animals capable of bipedal movement, animals who would now be placed in a position where its use would be much more necessary than in the arboreal settings that were home to their ancestors.
Other evidence indicates that beginning around 525,000 ybp there was a major aridification in east Africa, one that appears to have had a strong impact on the hominin population of the region. This dry period, which is thought to have lasted some 125,000 years, may have driven the humans of east Africa to travel more widely in search of resources. This travel in turn may have led to increased interaction with other hominin groups, perhaps resulting in exchanges of information. I find this to be crucially important because, historically, interactions between and among humans have tended to generate new ideas and important technological changes. The arid period was part of a larger era of climate variability, one in which the human toolkit was becoming more diversified and post-Acheulean traditions were emerging. There is evidence that these new tools were becoming more geographically widespread as well.53
One group of researchers has zeroed in on the influence of pathogens as a key element in human evolution, and they believe climate had only a relatively minor role to play. Using genetic analysis, these investigators have concluded that it was adaptation to the selection pressures imposed by local pathogens that may have had an effect on human genetic variability.54
And Steven Pinker, who has
written extensively about the human mind, argues persuasively that humans came
to occupy what other researchers have designated as a cognitive niche. This
concept is so important that I would like to quote Pinker at some length:
In biology, a “niche” is sometimes defined as “the role an organism occupies in an ecosystem.” The cognitive niche is a loose extension of this concept, based on the idea that in any ecosystem, the possibility exists for an organism to overtake other organisms’ fixed defenses by cause-and-effect reasoning and cooperative action—to deploy information and inference, rather than particular features of physics and chemistry, to extract resources from other organisms in opposition to their adaptations to protect those resources. These inferences are played out internally in mental models of the world, governed by intuitive conceptions of physics, biology, and psychology, including the psychology of animals. It allows humans to invent tools, traps, and weapons, to extract poisons and drugs from other animals and plants, and to engage in coordinated action, for example, fanning out over a landscape to drive and concentrate game, in effect functioning like a huge superorganism. These cognitive stratagems are devised on the fly in endless combination suitable to the local ecology. They arise by mental design and are deployed, tested, and fine-tuned by feedback in the lifetimes of individuals, rather than arising by random mutation and being tuned over generations by the slow feedback of differential survival and reproduction. Because humans develop offenses in real time that other organisms can defend themselves against only in evolutionary time, humans have a tremendous advantage in evolutionary arms races.55
The three human traits that, according to Pinker, truly stand out in comparison to the rest of the animal kingdom are technological know-how, cooperation among non-related individuals, and the development of grammatical language. Language’s power is demonstrated by a startling fact Pinker cites: according to an estimate devised in 1950, the typical English speaker can readily produce or understand 1020 unique sentences. This in turn makes possible a virtually infinite number of possible sentences about specific events. It was the combination of know-how, cooperation, and cognition, Pinker believes, that was selected for in the evolution of modern humans, and there is genetic evidence to support this contention. 56
So it would appear, in my view, that much of the evolution of consciousness in anatomically modern humans was driven by environmental change, change that required mental flexibility. It seems that those humans who combined certain talents in the right way or who possessed genes that conferred resistance to disease or facility in survival skills were the most successful at adapting to shifting, dynamic conditions. These survival skills were mutually reinforcing. Survival depended on the possession of fluid intelligence, the mental ability to deal with new or unexpected situations. Those who were most agile in mind had a crucial advantage over those who were less agile.
In the second chapter of this volume we examined the social brain hypothesis. Now we will look at this idea more closely. In an important article from 1998, a prominent researcher in the field of evolutionary psychology, Robin Dunbar, weighed the various hypotheses thought to account for the evolution of an advanced brain. Focusing on the development of the neocortex, this scientist carefully weighed the external variables thought to influence such growth (such as the growth of overall body size, maternal diet, foraging activity, the creation of mental maps, and so on). The conclusion he came to was striking: Neocortical size correlates with social group size. Human interaction is essentially information processing. The limits of human information processing constrain the size of social groups. Group size appears to rest on the following variables: restrictions on group size based on the ability to recognize other group members and their behavior, which rests on visual cues; the ability to memorize faces; the ability to keep track of which members have relationships with others; the ability to manipulate information about these relationships; and “the capacity to process emotional information”, through the processing of information about the emotional state of others in the group.
Dunbar points out that humans can usually associate about 2,000 names with faces, but the circle of people they identify with most closely is generally around 150. Various groups within human society “seem to cluster rather tightly around a series of values (5, 12, 35, 150, 500, and 2,000) with virtually no overlap in the variance around these characteristic values. They seem to represent points of stability or clustering in the degrees of familiarity within the broad range of human relationships, from the most intimate to the most tenuous.”
What struck me most in this research, however, was the role in social interaction of “mind reading”, the attempt to ascertain the meaning of what other people are saying, and the frequency of deception and manipulation in human social relationships. (Even non-human primates appear to use deceptive tactics at times.) I was particularly interested in this passage:
For humans, one important aspect of [Theory of Mind] concerns its relevance to language, a communication medium that crucially depends on understanding interlocutors’ mental states or intentions. The kinds of metaphorical uses of language that characterize not only our rather telegraphic everyday exchanges (in which ‘‘you know what I mean?’’ is a common terminal clause) but also lies at the very heart of the metaphorical features of language. As studies of pragmatics have amply demonstrated, a great deal of linguistic communication is based on metaphor: Understanding the intentions behind a metaphor is crucial to successful communication. Failure to understand these intentions commonly results in confusion or inappropriate responses. Indeed, without these abilities it is doubtful whether literature, notably poetry, would be possible. Our conversations would be confined to the banally factual; those fine nuances of meaning that create both the ambiguities of politeness and the subtleties of public relations would not be possible.57
So human social interaction, resting as it does on the imprecise medium of language, whether spoken, written, or gesture-based, is fraught with misunderstanding, confusion, misinterpretation, and miscommunication. And yet, it was through such interaction that much of the development of the neocortex was effected, the neocortex which makes communication possible.
The Expansion of Human Consciousness in Prehistory
In Volume One we examined a
number of breakthroughs that humans made during the Paleolithic era. Among such
breakthroughs was the ability to use, and then generate, fire. We noted, too,
that tool manufacture became more organized, and among such tools were hunting
weapons, by which we can infer the rise of cooperative human effort. All of
these developments are significant. Yet, it was not until the first genuine art
that we see any true hint of symbolic thinking, and only when we see smaller,
more sophisticated tools appear in the archaeological record that we see
evidence of advanced human innovation.
Much of the evidence seems to indicate that the critical period was between 400,000 and 50,000 ybp, during which the evolution of Homo sapiens took place. There are differences of opinion about what to label this era. Some have called it “the human revolution” while others prefer “the cognitive revolution”. Still others reject the whole concept of “revolution”, seeing it as misleading. What occurred during this time was the emergence of advanced art forms, syntactical language, refined tool making, and true social organization. There can be no doubt that during it humans crossed a critical threshold. But what precipitated this emergence, when were its most significant milestones reached, and what changes in human life (and in humans themselves) caused it?
Merlin Donald argues that what occurred through the evolutionary process was what might be called “the Great Hominid Escape from the Nervous System”. By this he means that the rise of complex human culture gave humans critical abilities that they could not have acquired in isolation. As he puts it,
…humans link with a vast and diverse cultural matrix in early infancy and profit from the rich storehouses of knowledge and skill that have accumulated in our cultural memory over many millennia. Since cultural knowledge accumulates rapidly, there can be dramatic differences between human cultures. Our dependency on culture is very deep and extends to the very existence of certain kinds of symbolic representation and thought. Socially isolated humans do not develop language or any form of symbolic thought and have no true symbols of any kind.58
Since language is the essential foundation upon which advanced human culture rests, the approximate date by which spoken language emerged is a significant issue. One researcher hypothesizes that language changed from gestures and verbal clicks to sound-based language before humans began to leave Africa.59 Some research centers on the FOXP2 gene, which we have encountered before, a gene which may be implicated in the acquisition by humans of speech. FOXP2 may have appeared in the human genome anywhere from 45,000 years ago to more than 100,000 years ago.60
So, it would seem that we need to look for the point where human culture and human social interaction reached a sort of critical mass, a synergy that allowed for the emergence of the full potential of the sapiens brain. Once this potential was unlocked, human ingenuity skyrocketed. A date of 30,000 BCE has been proposed as the point where we can see this ingenuity manifesting itself unmistakably, but there is no universal agreement on this point. And the true breakthrough may have come earlier. A prominent neuroscientist put forth an intriguing hypothesis in 2019: a genetic change about 70,000 ybp altered the prefrontal cortex and made possible the development of recursive language. Recursive language allows humans to form grammatically complex sentences, ones in which phrases can be inserted within other phrases or added to existing phrases. Such phrases can be re-worded, moved around, or refer to themselves. This capacity allows humans to form the enormous number of possible sentences that we noted above. This researcher notes that while hominins had the necessary speech apparatus by 600,000 ybp, such things as the fashioning of art that reflected actual objects, the creation of small tools such as bone needles, the building of shelters, and burials of the dead that show signs of ritual, don’t appear in the archaeological record earlier than around 70,000 ybp. As he puts it,
It is this synthesis that is crucial to advanced human communication and hence social interaction. There is no consensus as yet in support of this 70,000 ybp date, but the evidence bears further examination.
In the 1990s a new and highly controversial concept emerged in the field of neuroscience, the purported significance of mirror neurons. This idea is most closely associated with neuroscientist V.S. Ramachandran. Mirror neurons were first noted in macaque monkeys. Research discovered that certain neurons “lit up” when these monkeys observed other monkeys performing the same behaviors as they. In other words, these monkeys were recognizing behavioral similarities in others. A great deal has been written on this subject, since the existence and role of such neurons would seem to be the foundation of much of social interaction. But we must be cautious in regard to mirror neurons, since a great deal remains to be learned about them. It appears that mirror neurons are present in all the regions of the brain involved in motor functions, but key questions about their role in learning remain unanswered.62
Conclusions
It should be noted immediately that there is no general agreement about which combination of factors brought about the rise of human consciousness, an emergence that took place within the context of the development of the broader human mind. The rise of sentience, coupled with fortuitous genetic changes, laid the foundations of consciousness. The routes by which intelligence emerged in animals were diverse, and demonstrate that consciousness has a physical basis and is invariably embodied. The primate path proved to be the most cognitively useful, and the branching off of the hominids from the line that led to the chimpanzees was decisive. The mental abilities that emerged in the hominid line proved to be evolutionarily useful, even though these abilities were a biological “accident”, unplanned, and not foreordained. The dynamic, challenging external physical environment rewarded those who were smart enough and skilled enough (or simply lucky enough) to survive it.
Through an analysis of the earliest tools and works of art, we can trace, albeit incompletely, the growth of human cognitive abilities. Such growth did not proceed at an even pace, nor was it identical in every region. But somewhere between 70,000 and 30,000 years ago the sapiens brain began to demonstrate its full potential, well after the evolution of the sapiens line itself. Aided, perhaps, by genetic changes and spurred on by human social interaction, human abilities facilitated the construction of genuinely complex cultures, which in turn encouraged more interaction and stimulated greater cultural achievements. The end result of this process was ultimately the human world in which we live today.
In the next section of this work we will examine various aspects of the human mind and human consciousness in particular. Again, we must approach these subjects as distinct entities for the sake of clarity, but we must remind ourselves that they operate in very complex and intricate interaction with each other. In conducting this examination, we will perhaps gain a deeper understanding of the interior universe that has been our home our entire lives. But we can never hope to know that universe in its fullness. Such knowledge will probably be forever beyond us.
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