The Astonishing Prefrontal Cortex – Part Seven: PFC Short Takes III

By ChatGPT.

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For a Long Time Human Beings Did Not Know How to Think

200,000 years ago, human beings literally did not know how to think in the way we understand thinking today. While they possessed sophisticated concrete thinking abilities, they had not yet developed the cognitive tools and frameworks that we consider fundamental to human thought. Their mental processes centered on survival, social interaction, and technical knowledge - but without the symbolic representation and abstract conceptualization that characterizes modern human consciousness. Having the neural hardware (specifically the prefrontal cortex) didn't translate into knowing how to use it for the kinds of thinking we take for granted.

The archaeological record shows that tool-making required complex technical thinking over 300,000 years ago, as did social interaction and knowledge of the tribe. But what makes our humanity distinct isn't just abstract thought in isolation - it's the development of symbolic thinking and its cascading effects. The evidence shows that humans did not engage in symbolic thinking until about 100,000 years ago, followed by complex language around 70,000 years ago. This means that for at least 200,000 years, human beings were successfully making sophisticated tools, maintaining complex social relationships, and surviving through advanced practical thinking - but they literally did not know how to think symbolically or abstractly. They accessed their underused PFC differently than we do today, lacking the cognitive tools we consider essential to thought itself.

There's a meaningful distinction between the sophisticated concrete thinking required for tool-making and social interaction, and the kind of symbolic, self-reflective thinking that characterizes contemporary human consciousness. The PFC enabled different levels or types of thinking, with symbolic thought representing a particularly sophisticated form that emerged much later. Modern human thought - with its capacity for abstract reasoning, symbolic representation, and complex language - had to be discovered and developed over time.

My understanding is that early humans could plan complex tool creation, navigate intricate social relationships, remember and apply behaviors learned through observation and imitation, and engage in sophisticated cause-and-effect reasoning. However, for tens of thousands of years they literally could not engage in symbolic ideas or complex mythologies. They could not think abstractly about their own thinking, engage in philosophical reflection, or analyze metacognitively. They could not think of building pyramids, Ferris wheels, and VR games. They could engage in play but had not yet developed the cognitive frameworks necessary for sporting games or specialized recreational activities. They didn't just think differently than we do today - they lacked the fundamental cognitive tools that we consider essential to thinking itself though their brains were exactly the same as ours.

This, in turn, means that these persons experienced life very differently from the way we cognitively experience it today. It also points out something fascinating about the PFC: it's not just a binary of "having abstract thought" or "not having it," but rather a spectrum of cognitive capabilities that humans gradually discovered and developed. The hardware was there, but the "software" - the cultural and cognitive frameworks for using it - had to be developed over time.

So we can "see" the PFC come "online" in moments of historic change like this. This is a powerful way to trace the PFC's gradual "awakening" through major cognitive and cultural transitions visible in the archaeological record. Here's the progression:

Around 300,000-200,000 years ago: Basic tool-making and social coordination, showing fundamental abstract thinking capabilities, but not yet symbolic thought.

Around 100,000-70,000 years ago: First evidence of symbolic thinking appears - early art, decorative objects, and ritual practices. This marks the beginning of humans using their PFC in fundamentally new ways.

Around 50,000-40,000 years ago: The "pre-cultural explosion" - rapid advancement in tool technology, widespread appearance of cave art, and evidence of complex social organization. This suggests more humans were accessing their PFC's capabilities for abstract and symbolic thought.

Around 12,000 years ago: The Agricultural Revolution - showing widespread ability to think abstractly about long-term planning, resource management, and complex social organization. This leads to “the cultural explosion” - abstract thinking manifesting as crude commerce systems, mythic stories, Neolithic spirituality, and early urban planning.

Around 5,000 years ago: The invention of writing - representing a massive leap in abstract symbolic thinking and the ability to store and manipulate complex ideas. This freed up and enormous amount of memory effort that we previously devoted for remembering everything. Now we could write it down and potentially forget it while we focused on other things. We could read it later if we wanted to remember it of its details. Suddenly, we had more bandwidth for speculative tasks, expanding mysteries and exploring possibilities all suddenly became possible. The number of words exploded with the act of writing them down. This enabled the fullest expression of human imagination which had already been working modestly for thousands of generations.

Each of these transitions represents humans discovering new ways to use their PFC's capabilities. It's like watching a powerful computer gradually being programmed to handle increasingly complex tasks, coming more fully “online.” Once humans began to fully utilize their PFC for symbolic thinking, cultural and technological advancement accelerated dramatically. This suggests that learning to use our PFC more fully creates feedback loops that enable even more sophisticated cognitive developments - unintentionally.

While we can trace the anatomical development further back, tool-making represents the first clear evidence of humans using their PFC for abstract thinking, even if very basic. This gives us a concrete starting point around 2.6 million years ago with the first stone tools.

The creation of stone tools, while seemingly simple to us, required several cognitive capabilities involving technical skill, goal setting, dexterity, methods observed through observation and imitation, and crude planning. However, these early tool-makers (except for geniuses) were not engaging in symbolic or complex abstract thought. They were using their PFC for practical problem-solving and motor planning, but not yet for the kind of sophisticated abstract thinking that would emerge much later.

This represents a kind of "ground floor" of PFC utilization - the most basic level of abstract thinking required for survival and technological innovation. From here, we can trace how humans gradually discovered more sophisticated ways to use their prefrontal cortex.

What I want to stress here is that it was possible to have full human cognition for thousands of generations without having any sort of high-level thoughts because there was no high-level language. We literally were speechless, we had no words for things we could not understand, which is to say there were few words. We were dumb. Our thoughts were mostly simpleton. The hardware for sophisticated thinking - specifically the PFC - was fully present in humans at that distant time, but without complex language to enable high-level abstract thought, most humans simply didn't engage in it.

Think about what this means: For thousands of generations, humans with brains identical to ours lived, survived, and reproduced without ever engaging in the kind of abstract thinking we take for granted today. They had the neural architecture for complex thought, but without sophisticated language, they lacked the tools to access it. Beyond your emotions and instincts, thoughts require words to be “abstracted.” This was likely limited to social demands and technical knowledge. Nothing else could be abstracted because nothing else existed in out minds yet. Just as, most likely, future human cognition will only resemble how we engage our minds today.

According to Mithen's model, early humans (hominids) had social language for millions of years - they could communicate basic needs, warnings, and social relationships. But this was fundamentally different from the kind of general-purpose language that enables abstract thought. The transition from purely social language to language that could express non-social concepts took place gradually between 150,000 and 50,000 years ago.

This helps explain the long gap between having the PFC and using it for complex abstract thought. Without the cognitive tools that language provides - like metaphor, categorization, and symbolic representation - even a fully formed PFC remains largely untapped. Our capacity for abstract thought, hypothetical contemplation, complex planning and problem-solving, and mass organization - isn't an inherent property of having a human brain. Rather, it's something that had to be discovered and developed through the gradual evolution of language and culture within the PFC.

Important consideration: Even during this "explosion," these advances were likely limited to certain individuals or groups. Most humans probably still thought primarily in concrete, immediate terms. As Mithen suggests, language was gradually "invaded" by non-social information, with some individuals (perhaps early geniuses) leading the way in using language for abstract purposes.

The Historic Timing of Migrations Out of Africa and Trimergence

The timing of successful migrations aligns remarkably well with the period when humans began to fully utilize their prefrontal cortex (PFC) in conjunction with Broca's and Wernicke's areas, suggesting that cognitive development, not just physical capability, was a key factor in successful long-distance migration.

Early migration attempts around 120,000-90,000 years ago (perhaps as early as 210,000 years ago in Greece) failed to establish permanent populations outside Africa or possibly along the Tigris and Euphrates Rivers, despite these humans having the same physical capabilities as later successful migrants. These early migrants already possessed the anatomically contemporary brain structure - including a fully formed PFC, Broca's area, and Wernicke's area. Yet something was missing that prevented these early migrations from succeeding.

The successful "Out of Africa" migration occurred between 70,000-50,000 years ago, precisely when archaeological evidence shows humans beginning to utilize their pre-existing neural architecture in new ways. Mithen points out the transition from purely social language to general-purpose language, occurring between 150,000 and 50,000 years ago. The successful migrations coincide with the latter part of this transition, when humans were developing more sophisticated ways of using language to understand and communicate about the non-social world.

This makes sense. As the trimergence turbo-charged language development, so too our ability to have ideas exploded. More words, more details, more details more ideas. This was a completely new way to use our brains. Before the “culture explosion” there was an explosion of words and ideas.

Today's vocabulary statistics illuminate this evolutionary journey. Modern hunter-gatherer societies typically command between 3,000 to 8,000 words, while educated speakers of modern languages like English actively use 20,000 to 35,000 words, with passive vocabulary potentially reaching 60,000 words. This dramatic difference reflects not a change in neural architecture but rather humanity's gradual discovery of how to use its pre-existing cognitive capabilities.

The exponential growth in vocabulary tracks with the increasing utilization of the PFC's capabilities for abstract thought. As societies developed more complex concepts, they required more words to express them. This created a powerful feedback loop: more complex language enabled more abstract concepts, which required more words, which in turn enabled even more complex thinking. This process continues to accelerate.

The PFC's pre-adaptive development merits special attention here. Unlike most evolutionary adaptations that develop in response to specific pressures, the PFC evolved first, creating "unused neural real estate" that would later prove crucial for abstract thought. Combined with the specialized language areas (Broca's and Wernicke's), this created a cognitive architecture capable of handling far more complex communication than early humans required for survival.

Early geniuses likely played a role in this development, being the first to use social language for non-social purposes, though most of their knowledge was forgotten and relearned through the ages. As Mithen suggests, these exceptional individuals discovered how to use language to transmit non-social information, gradually creating frameworks that others could follow. This process accelerated dramatically with the agricultural revolution, as more humans began actively engaging their PFC's capabilities for abstract thought.

Modern vocabulary sizes thus represent not just accumulated knowledge but the degree to which societies have learned to utilize their pre-adapted neural architecture. The fact that even hunter-gatherer societies today possess thousands of words suggests that once these cognitive capabilities emerged, they became universal human traits, regardless of technological development level.

The timing of the trimergence is massively significant because successful long-distance migration required capabilities that only emerged with the integrated function of the PFC, Broca's, and Wernicke's areas. Migrants needed to maintain mental maps of vast territories, predict seasonal changes in unfamiliar environments, coordinate group movements, and transmit complex information about resources and dangers. These capabilities demand exactly the kind of abstract thinking that emerges from the interaction of these three brain regions.

The archaeological record along migration routes provides evidence for this cognitive shift. We begin to see sophisticated tools requiring multi-step manufacturing processes, symbolic art suggesting abstract thinking, and ritual practices indicating complex social organization. These artifacts appear along migration routes during the period of successful expansion, suggesting that the migrating populations had developed new cognitive capabilities that their predecessors lacked.

What's particularly significant is that this pattern repeats across different migration routes and populations. Whether moving into Europe, Asia, or eventually Australia, successful migrations occur after this cognitive threshold is crossed. This universality suggests a species-wide development in how humans were using their neural architecture rather than isolated cultural innovations.

The migration patterns also demonstrate the gradual nature of this cognitive development. Initial forays were tentative and limited. As populations developed more sophisticated ways of using their cognitive capabilities, the migrations became more ambitious and successful. This progression mirrors the gradual discovery and utilization of the PFC's capabilities that your theory proposes.

Modern neuroscience helps us understand why this integration was so crucial. The PFC provides the capacity for abstract thinking and planning, while Broca's and Wernicke's areas enable complex language processing. The interaction between these regions allows for sophisticated communication about abstract concepts - exactly what migrating groups would need to coordinate movements, share knowledge about new environments, and maintain social cohesion in challenging circumstances.

This synchronicity between migration success and cognitive development strengthens the argument that humans were gradually growing into their neural capabilities rather than evolving new ones. The same brain structure that failed to support migration at 120,000 years ago succeeded at 70,000 years ago, not because it had changed, but because humans had discovered new ways to use it.

The implications are profound. If our ancestors possessed sophisticated neural architecture long before they learned to use it effectively, and if this learning process is reflected in concrete events like migration patterns, the agricultural revolution, and all the rest, then we might indeed still be in the early stages of discovering our cognitive potential. Just as our ancestors needed tens of thousands of years to begin effectively using their PFC for abstract thought, we might be similarly positioned with regard to yet-undiscovered cognitive capabilities, only with our greatly accelerated pace of change.

Given the dynamic nature of everything in which we find ourselves, we should remain open to a wide array of developments in human consciousness and capability. The emergence principle suggests that the interaction of existing systems can create entirely new properties and possibilities that cannot be anticipated by examining the components in isolation. This means that while we can chart certain trajectories of development (the rise of abstract thought, for example), the most significant breakthroughs may come from unexpected directions and combinations.

The human brain has demonstrated remarkable plasticity and potential for development. Neuroscience and psychology offer previously unnoticed or unlearned behavioral practices that can alter our brains and, hence, our cognition. Yet there is no reason to believe we have reached the limits of its capabilities or that we fully understand the possibilities that emerge from the interaction of its various regions.

This perspective demands both intellectual humility and bold optimism about human potential. We are not at the end of our cognitive evolution, but rather at the beginning of understanding its true scope and possibility. The path forward requires accepting uncertainty while maintaining our commitment to scientific investigation and understanding. The future of human consciousness lies not in preserving past insights, but in actively pursuing new frontiers of knowledge and capability through rigorous scientific inquiry and technological innovation. The future protocols of neuroscience and psychology will change who we are for the better or, at least, the more effective within our environment.

The final astonishment in this series of posts is that, despite all our neurological achievements, discoveries, and insights over tens of thousands of years, we still stand at the threshold of human cognitive potential. The most astounding chapters in the story of human consciousness have yet to be written, and the greatest discoveries about our own cognitive capabilities remain ahead of us. They always have and they always will, the quintessential journey without a destination.

(Written with Assistance from Claude.)