There are what I call “hard” and “soft” interpretations of Jaynes’s thesis. The “hard” interpretation is exactly what is posited in the book: humans did not have reflexive self-awareness in the way we describe it today until roughly the Bronze Age.
The “soft” interpretation is that a shift in consciousness occurred, quite possibly in the way that Jaynes described it, but that it occurred around 40-70,000 years ago during the Ice Age, long before writing or complex civilizations, when our ancestors will still hunter-gatherers. Another “soft” interpretation is that our ancestors definitely thought differently than we do, but they were still conscious agents nonetheless, and that the gods and spirits they referred to so often and who seemed to control their lives were merely figments of their imagination.
The Great Leap Forward
The idea that humans experienced some some sort of significant cognitive transformation sometime after becoming anatomically modern is no longer controversial. This is the standard view in archaeology. Scientists call this the transition from anatomically modern humans to behaviorally modern humans. This article has a good summary:
… During the Upper Paleolithic (45,000-12,000 years ago), Homo sapiens fossils first appear in Europe together with complex stone tool technology, carved bone tools, complex projectile weapons, advanced techniques for using fire, cave art, beads and other personal adornments. Similar behaviors are either universal or very nearly so among recent humans, and thus, archaeologists cite evidence for these behaviors as proof of human behavioral modernity.
Yet, the oldest Homo sapiens fossils occur between 100,000-200,000 years ago in Africa and southern Asia and in contexts lacking clear and consistent evidence for such behavioral modernity. For decades anthropologists contrasted these earlier “archaic” African and Asian humans with their “behaviorally-modern” Upper Paleolithic counterparts, explaining the differences between them in terms of a single “Human Revolution” that fundamentally changed human biology and behavior.
Archaeologists disagree about the causes, timing, pace, and characteristics of this revolution, but there is a consensus that the behavior of the earliest Homo sapiens was significantly different than that of more-recent “modern” humans.
Earliest humans not so different from us, research suggests (Science Daily)
What no one knows, however, is what caused it, how it took place, or exactly when and where it took place. But the idea that there could be some kind of drastic cognitive shift without significant physical changes is no longer fringe. As Jared Diamond wrote:
Obviously, some momentous change took place in our ancestors’ capabilities between about 100,000 and 50,000 years ago. That Great Leap Forward poses two major unresolved questions, regarding its triggering cause and it geographic location. As for its cause, I argued in my book The Third Chimpanzee for the perfection of the voice box and hence the anatomical basis for modern language, on which the exercise of human creativity is so dependent. Others have suggested instead that a change in brain organization around that time, without a change in brain size, made modern language possible. Jared Diamond; Guns, Germs and Steel, p.40
Archaeologists tend look at all the things in the archaeological record that indicate that Paleolithic humans were like us (e.g. complex tools, art, body ornamentation, trade, burial of the dead, food storage and preservation), but for some reason they downplay or dismiss all the things that show that, in many ways, they were quite different than us. That is, in some respects, they were not nearly as “behaviorally modern” as we tend to assume.
For example, here are some other things they did during this time period: carve ivory and wooden idols. Make sacrifices to their gods (including mass child sacrifice). Cannibalism. Sleep temples. Build strange statues with eyes and no mouth (eye idols). Practiced astrology. And they regularly poked holes in their skulls for reasons we are still unsure of. In other words, for all the evidence that they thought like us, there is other evidence that suggests that their thinking was substantially different that ours in many ways! But we tend to emphasize the former only, and ignore the latter. This leads to Jaynes’s idea that there may have been more than just one Great Leap Forward, and that human consciousness has changed significantly since the establishment of architectural civilizations.
Let’s take a quick detour into how scientists think the human brain may have developed to gain some insight into whether there may be evidence for bicameralism.
A short digression into brain architecture
The idea that the brain is composed of previous adaptations which have been extended is fairly well accepted. The Triune Brain hypothesis is that we have a “lizard brain” which controls our base functions like breathing and so forth, and is highly aggressive and territorial. Then we have a rodent (paleomammalian) brain that allow us do more complex social functions such as solve basic problems. Then we have the primate (neomammalian) brain including the neocortex that allows for larger groups and advanced reasoning. This is basically seen as correct in broad strokes, although a vast oversimplification of the complexities of how the primate brain developed
The brain of an organism cannot just “go down” for maintenance while it upgrades. It has to keep the organism alive and reproducing. So new modules have to be added on the fly to what’s already there ad hoc. This leads to a brain of aggregations which have to mix with older features, much the way legacy computer code is embedded within older software. This, as you can imagine, can lead to “buggy code.”
Archaeologist Steven Mithen wrote a book about the prehistory of the mind—what we might call “cognitive archaeology.” He notes that certain processes seem to come automatically to the brain—like learning language, while others—like multiplying two large numbers together in one’s head, do not. This means that the brains is not like, say, a “general purpose” I/O microcomputer as it’s often described. He writes: “The mind doesn’t just accumulate information and regurgitate it. And nor is it indiscriminate in the knowledge it soaks up. My children—like all children—have soaked up thousands of words effortlessly, but their suction seems to lose its power when it comes to multiplication tables.”
This indicates that the human mind has some inherent, or built-in, propensities, alongside the general intelligence all animals have. That means they may be of evolutionary origin. Spoken language appears to be one of these. While we send our kids to school for years to try and pound algebra, trigonometry and the correct spelling of words into them, children soak up language from their environment shortly after birth with hardly any effort at all.
Noam Chomsky invoked something he called the “poverty of the stimulus” to make this point. He meant that given how fast and accurately children learn language by osmosis, there is no way it comes from “just” environmental inputs, like a computer. Children must be, in some sense, be pre-programmed to learn language, and thus language’s fundamental construction must be related to how the brain functions—something he called a “universal grammar.” Over time, more of these apparently “inherent” behaviors have been identified in humans:
It became increasingly unpopular to assume that a basic understanding of the world can be built entirely from experience. This was in part instigated by theorist Noam Chomsky, who argued that something as complex as the rules of grammar cannot be picked up from exposure to speech, but is supplied by an innate “language faculty.”
Others followed suit and defined further “core areas” in which knowledge allegedly cannot be pieced together from experience but must be innate. One such area is our knowledge of others’ minds. Some even argue that a basic knowledge of others’ minds is not only possessed by human infants, but must be evolutionarily old and hence shared by our nearest living relatives, the great apes.
Children understand far more about other minds than long believed (The Conversation)
This means that, rather than being like a computer or a sponge, argues Mithen, the mind is more akin to a “Swiss army knife,” with different modules for different uses, but all fundamentally a part of the same basic “object.” One study, for example, has found that the ability recognize faces is innate. This explains the human penchant for pareidolia.
Using the Swiss Army knife metaphor, Mithen argues that these various specialized cognitive modules overlap with what he calls “general intelligence.” This overlap between specialized intelligences and the general intelligence leads to a lot of unique features of human cognition such as creativity, socialization, and, perhaps, constructing things like ‘gods’ and the ‘self.’ Here’s a good summary:
Mithen…[argues]…that the mind should … be seen as a series of specialized “cognitive domains” or “intelligences,” each of which is dedicated to some specific type of behavior, such as specialized modules for acquiring language, or tool-using abilities, or engaging in social interaction…his argument will be that that modern human mind has an architecture built up by millions of years of evolution, which finally yielded a mind that creates, thinks, and imagines.
Mithen…highlights recent efforts in psychology to move beyond thinking of the mind as running a general-purpose program, or as a sponge indiscriminately soaking up whatever information is around. A new analogy for the human mind has taken its place: the Swiss army knife, a tool with specialized devices, designed for coping with very special types of problems.
This is found especially in Howard Gardener’s important book Frames of Mind: The Theory of Multiple Intelligences. In this well-known work we are presented with a Swiss-army knife architectural model for the mind, with each “blade,” or cognitive domain, described as a specialized intelligence. Gardener initially identified seven intelligences: linguistic, musical, logical-mathematical, spatial, bodily-kinesthetic, and two forms of personal intelligence (one for looking at on’es own mind, one for looking outward toward others).
Alone in the World? by Wentzel Van Huyssteen, pp. 194-195
Form this, Mithen proposes a new metaphor – that of a cathedral, with a central nave standing in for generalized intelligence, and numerous walled-off enclaves (side chapels) for the various specialized cognitive functions. In a nutshell, Mithen argues that the “walls” between these areas began to break down over time, and the services in the side chapels increasingly blended together with the “main service” taking place in the nave. The mixture gives rise to rise to the various symbolic and metaphorical aspects of human consciousness—what he terms “cognitive fluidity.”
Mithen fills out the three stages in the historical development of the human mind as follows:
In Phase One human minds were dominated by central “nave” of generalized intelligence.
Phase Two adds multiple “chapels” of specialized intelligences, including the cognitive domains of language, social intelligence, technical intelligence, and natural history intelligence.
Phase Three brings us to the modern mind in which the “chapels” or cognitive domains have been connected, resulting in what Mithen calls cognitive fluidity. This creative combination of the various cognitive domains of the mind would ultimately have profound consequences for the nature of the human mind. With this cognitive fluidity, the mind acquired not only the ability for, but also a positive passion for, metaphor and analogy. And with thoughts originating in different domains engaging one another, the result is an almost limitless capacity for imagination.
It is exactly this amazing ability that would make our species so different from early humans who shared the same basic mind – a Swiss army knife of multiple intelligences, but with very little interaction between them.
Mithen’s useful model here, again, is a cathedral with several isolated chapels, within which unique services of thought were undertaken, each barely audible elsewhere in the cathedral. In Mithen’s words: “Early humans seem to have been so much like us in some respects, because they had these socialized cognitive domains; but they seem so different because they lacked the vital ingredient of the modern mind: cognitive fluidity”
[Behavioral modernity] is when “doors and windows were inserted between chapel walls”, when thoughts and information began flowing freely among the diverse cognitive domains or intelligences. Specialized intelligences no longer had to work in isolation, but a a”mapping across knowledge systems” now became possible, and from this “transformation of conceptual spaces” creativity could now arise as never before.
Mithen thus appropriates some of the work of cognitive psychologists, to make the related point that in both development and evolution the human mind undergoes (or has undergone) a transformation from being constituted by a series of relatively independent cognitive domains to a situation in which ideas, ways of thinking, and knowledge now flow freely between such domains. This forms the basis for the highly plausible hypothesis that during this amazing emergent period of transition, the human brain was finally hardwired for cognitive fluidity, yielding imagination and creativity.
Alone in the World? by Wentzel Van Huyssteen pp. 195-197
And modern scientific investigation tends to back these ideas up:
The ability to switch between networks is a vital aspect of creativity. For instance, focusing on a creative puzzle with all of your attention might recruit the skills of the executive attention network. On the other hand, if the creative task involves producing a sonically pleasing guitar solo, focus might be switched from intense concentration to areas more involved in emotional content and auditory processing.
The neuroscience of creativity (Medical News Today)
It is this mixing of intelligences – this cognitive fluidity, that gives rise to language and symbolic thinking. Incremental at first, the increasing blending of these intelligences gives rise to language and symbolic thought over time. This leads to the “Great Leap Forward” seen in the archaeological record:
Of critical importance here is also a marked change in the nature of consciousness. Mithen has argued that reflexive consciousness evolved as a critical feature of social intelligence, as it enabled our ancestors to predict the behavior of other individuals. He then makes the point that there is now reason to expect early humans to have had an awareness about their own knowledge and thought processes concerning the nonsocial world. Via the mechanism of language, however, social intelligence began to be invaded by nonsocial information, and the nonsocial world becomes available for reflexive consciousness to explore…Consciousness then adopted the role of a comprehensive, integrating mechanism for knowledge that had previously been “trapped” in specialized intelligences.
The first step toward cognitive fluidity appears to have been integration between social and natural history intelligence in early modern humans around 100,000 years ago. The final step to full cognitive fluidity, the potential to entertain ideas that bring together elements from normally incongruous domains, occurred at different times in different populations between 60,000 and 30,000 years ago. This involved an integration of technical intelligence, and led to the cultural explosion we are now calling the appearance of the human mind.
…As soon as language started acting as a vehicle for delivering information into the mind, carrying with it snippets of nonsocial information…[it] now switched from a social to a general-purpose function, consciousness from a means to predict other individuals’ behavior to managing a mental database of information relating to all domains of behavior…Mithen’s most interesting point here is that some metaphors and analogies can be developed by drawing on knowledge within a single domain, but the most powerful ones are those that cross domain boundaries. By definition these kinds of metaphors can arise only within a cognitively fluid mind… Alone in the World, pp.197-199
Yes, but were they conscious? There’s the rub. Is artwork proof of reflective self-consciousness? Are burials proof of such? Clearly tool use alone is not, as we’ve seen. And some of the most vibrant artwork has been done by schizophrenics.
Like Mithen, Jaynes also calls attention to the vital role of language and metaphor in cognitive fluidity and reflective self-consciousness. Even ‘the self’ itself is a metaphor!
…The most fascinating property of language is its capacity to make metaphors … metaphor is not a mere extra trick of language…it is the very constitutive ground of language. I am using using metaphor here in its most general sense: the use of a term for one thing to describe another because of some kind of similarity between them of between their relations to other things.
There are thus always two terms in a metaphor, the thing to be described, which I shall call the metaphrand, and the thing or relation used to elucidate it, which I shall call the metaphier. A metaphor is always a known metaphier operating on a less known metaphrand.
It is by metaphor that language grows. The common reply to the question “what is it?” is, when the reply is difficult, or the experience unique, “well, it is like –.” In laboratory studies, both children and adults describing nonsense objects (or metaphrands) to others who cannot see them use extended metaphriers that with repetition become contracted onto labels. This is the major way in which the vocabulary of language is formed. The grand and vigorous function of metaphor is the generation of new language as it is needed, as human culture becomes more and more complex.
It is not always obvious that metaphor has played this all-important function. But this is because the concrete metaphiers become hidden in phonemic change, leaving the words to exist on their own. Even such an unmetaphorical-sounding word as the verb ‘to be’ was generated from a metaphor. it comes from the Sanskrit bhu, “to grow, or to make grow,” while the English forms ‘am’ and ‘is’ have evolved from the same root as the Sanskrit asmiy “to breathe.”
It is something of a lovely surprise that the irregular conjugation of our most nondescript verb is thus a record of a time when man had no independent word for ‘existence’ and could only say that something ‘grows” or that it ‘breathes.’ Of course we are not conscious that the concept of being is thus generated from a metaphor about growing and breathing. Abstract words are ancient coins whose concrete images in the busy give-and-take of talk have worn away with use. pp. 48-51
The ancient Greeks at the time of Homer lacked a word for blue; they referred to the Mediterranean Sea, for example, as “wine-colored” (οἶνοψ). The brilliant hues of the Mediterranean sunrise are famously described as “rosy-fingered” (ῥοδοδάκτυλος), and so forth. Wikipedia even has a list of them. A similar concept in Old Norse is called kenning (e.g blood = “battle sweat”).
In reading ancient texts, it is one of the rare opportunities we have to look upon a worldview entirely alien to us. The ancients described physical appearances in some ways that seem bizarre to the modern sensibility. Homer says the sea appears something like wine and so do sheep. Or else the sea is violet, just as are oxen and iron. Even more strangely, green is the color of honey and the color human faces turn under emotional distress. Yet no where in the ancient world is anything blue for no word for it existed. Things that seem blue to us are either green, black or simply dark in ancient texts.
Also, things like subjective perspective and experience are lacking. Even body parts are regularly described as having their own minds. And voices are supposedly heard in the external world, command voices telling people what to do, while voices aren’t described as being heard within the head. There is no ancient word or description of a fully internalized sense of self.
It’s hard to know what to make of all this. There are various theories that attempt to explain it. But the main takeaway is that our common sense assumptions are false. There is something more to human nature and human society than we at present experience and understand. As a species, we are barely getting to know ourselves.
Benjamin David Steele (Facebook post)
Note that in our discussion above, even our descriptions of the mind rely upon metaphors (“Swiss army knife,” “cathedral”) and spatialization (“leaping forward”).
Finally, there was a German theorist of religion named Max Müller who saw the origin of what we call ‘gods’ in the way that humans naturally tend to conceive of things they do not understand metaphorically. His theories have all but been forgotten, but I think they fit nicely with the idea that in order to comprehend certain natural phenomena, ancient peoples resorted to assigning them the category ‘god,’ even when they knew, for instance, that the sun was not literally the chariot of Apollo, or that lightning bolts were not literally thrown by Zeus. Keep in mind, what we think of when we hear the word ‘god’ in our rationalist, materialistic, monotheistic-influenced culture is probably so different than what the ancient people using it at the time meant, that we moderns cannot even conceive of what they had in mind. Here’s E. E. Evans-Pritchard describing Muller’s theories:
In [Müller’s] view, as I understand it, men have always had an intuition of the divine, the idea of the infinite–his word for God–deriving from sensory experience…Now, things which are intangible, like the sun and the sky, gave men the idea of the infinite and also furnished the material for deities…Müller did not wish to be understood as suggesting that religion began by men deifying natural objects, but rather that these gave him a feeling of the infinite and also served as symbols for it.
Müller was chiefly interested in the gods of India and of the classical world…His thesis was that the infinite, once the idea had arisen, could only be thought of in terms of metaphor and symbol, which could only be taken from what seemed majestic in the known world, such as the heavenly bodies, or rather their attributes. But these attributes then lost their original metaphorical sense and achieved autonomy by becoming personified as deities in their own right. The nomina became numina.
So religions, of this sort at any rate,might be described as a ‘disease of language’, a pithy but unfortunate expression which later Muller tried to explain away but never quite lived down. It follows, he held, that the only way we can discover the meaning of the religion of early man is by philological and etymological research, which restores to the names of the gods and the stories told about them their original sense.
Thus, Apollo loved Daphne; Daphne fled before him and was changed into a laurel tree. This legend makes no sense till we know that originally Apollo was a solar deity, and Daphne, the Greek name for the laurel, or rather the bay tree, was the name for the dawn. This tells us the original meaning of the myth: the sun chasing away the dawn.
E.E. Evans-Pritchard – Theories Of Primitive Religion, pp. 21-22