The human brain is a marvel of evolutionary engineering, layering sophisticated cognitive abilities atop ancient survival systems that some scientists say have kept our species alive for millions of years.
Three leading thinkers offer complementary perspectives on this relationship. Jeff Hawkins explores the structural interdependence of old and new brain systems, Ray Kurzweil examines how ancient drives shape modern behavior, and Robin Sharma provides strategies for transcending primitive limitations. Keep reading to see how these viewpoints come together to explain the ancient brain.
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The Architecture: Old Brain and Neocortex Working Together
In his book A Thousand Brains, neuroscientist Jeff Hawkins writes that, although the thousands of mini-brains that comprise your neocortex get all the credit for intelligent behavior, they’re far from the only important part of your brain. Instead, the neocortex is entirely dependent on the older, more primitive parts of your brain to interact with the outside environment at all.
(Shortform note: Modern neuroscience emphasizes that the brain works as an integrated network rather than as discrete “old” and “new” parts with a simple evolutionary hierarchy. All brain regions, regardless of their evolutionary age, collaborate to produce behavior and cognition.)
Hawkins explains that the human brain is divided into two main parts—the neocortex and what he calls “the Old Brain.” From an evolutionary perspective, the Old Brain is ancient and is similar to that in many animal species. It’s responsible for maintaining your basic biological functions and reflexes. In contrast, the neocortex is a more recent evolutionary development. It’s much larger in humans than in other species, accounting for 70% of your brain and acting as the source of your intelligence. The neocortex processes sensory information and, in humans, is capable of complex cognitive functions such as language and mathematics.
(Shortform note: Hawkins uses the term neocortex to refer to the entirety of what’s also known as the “cerebral cortex,” the brain’s large outer layer. However, that usage is only mostly correct. In humans, the neocortex makes up 90% of the cerebral cortex, though this ratio is lower in other animal species. The remaining portion of the cerebral cortex is the limbic lobe, a region between the neocortex and the Old Brain that governs emotional reactions, memory creation, and interpreting social cues in interactions. Meanwhile, the neocortex has its own divisions, including the frontal and parietal lobes involved in goal-setting and decision-making, the occipital lobe that handles visual processing, and the temporal lobe that lets us process language.)
Although your neocortex is where your higher thought processes reside, Hawkins writes that it doesn’t operate in isolation from your Old Brain. All sensory signals and motor commands must pass through the Old Brain before reaching the neocortex or being enacted by the body. Though the neocortex is divided into different regions that process specific types of information, such as vision, hearing, and language, these regions are highly interconnected. Every part of the neocortex is also connected to both the sensory inputs and the motor control areas of the Old Brain, indicating the close relationship between your senses, your thoughts, and your actions.
(Shortform note: By referring to the brain’s core as the Old Brain, Hawkins borrows language from the long-held and highly popularized Triune Brain Theory, which held that the parts of the brain near its base are “older” in the evolutionary sense. Today, this model has been largely abandoned. In Seven and a Half Lessons About the Brain, Barrett explains that the “old and new brain” theory relied on what brains look like to deduce what their regions can do. Instead, many parts of the brain collaborate to perform all its functions, even those previously subscribed to the so-called “Old Brain.” Hawkins’s theory accounts for this interdependence, even though he uses terms originating from the older model.)
Building on this structural understanding, computer scientist and inventor Ray Kurzweil provides a more detailed look at the specific ancient brain regions that shape our motivations and behaviors in his book How to Create a Mind.
Kurzweil explains that, while the neocortex handles sophisticated pattern recognition, it doesn’t operate in isolation. Instead, it works with much older brain structures that generate our basic drives and emotions. These ancient brain regions—including the amygdala (which triggers fear responses), the nucleus accumbens (which creates pleasure sensations), and other parts of the limbic system—create the motivations that kept our ancestors alive: seeking food, avoiding predators, finding mates, and protecting territory. But, according to Kurzweil, the neocortex doesn’t replace the drives generated by older brain regions; it simply redirects them.
(Shortform note: The brain reflects millions of years of evolutionary history, with newer cortical structures built on top of older, subcortical ones. Because the neocortex has to work through ancient brain regions that long predate it, this creates a bottleneck where even our most sophisticated cognitive processes have to work with the same basic motivational systems—like hunger, fear, and reward-seeking—that drove our ancestors. Researchers think our attention system may have evolved to manage this bottleneck: While the neocortex’s pattern recognition abilities are incredibly sophisticated, they’re constrained by having to utilize ancient neural architecture that only responds to basic motivational signals.)
Ancient Brain Functions in Modern Life
The partnership between ancient and modern brain structures manifests in concrete ways throughout our daily lives. Kurzweil notes that the old brain generates basic motivations through pleasure and fear responses, while the neocortex develops strategies to fulfill those drives. For instance, your drive to avoid danger might manifest as working diligently to impress your boss (keeping your job safe). The hunting instinct could be redirected into writing a book or competing in sports (channeling the drive to pursue and capture into achievement). The partnership between the neocortex and older parts of the brain explains why our behavior has both rational and emotional components.
(Shortform note: Neuroscientists agree with Kurzweil that we’re using ancient instincts to navigate our modern world. The emotional systems in the old brain are the first to screen incoming information, and they do so using biases that evolution hardwired into the brain. These biases helped our ancestors avoid the most costly errors, like mistaking a snake for a stick, at the expense of making lots of smaller, less costly mistakes. This creates a three-step process: First, the old brain screens the situation, treating things like career stress as survival threats. Second, it generates emotions and motivations based on those assessments. Third, the neocortex works with those biased emotional inputs to decide how to move forward.)
While Kurzweil focuses on how ancient drives are redirected into modern pursuits, leadership expert Robin Sharma addresses a more challenging aspect of this relationship: how the ancient brain can actively resist our efforts to grow and change.
In his book The 5 AM Club, Sharma writes that the ancient brain triggers chemical processes that ramp up your fear and activates your fight or flight reflex. You feel stressed or anxious, even when there is no immediate threat in your environment.
When you start the process of growth, the ancient brain kicks in. It recognizes that your comfort zone is being challenged and warns you against the invading dangers. This sensation creates self-sabotage, where you actively destroy the work and processes of growth and achievement. You might turn to distractions or allow negative thoughts to take over and keep you from attempting to become more.
Harnessing Higher Brain Functions
Despite these challenges, all three authors agree that understanding the ancient brain’s influence enables us to work more effectively with our complete neural system. Hawkins emphasizes that learning itself depends on the collaboration between old and new brain structures.
Hawkins is clear that the brain doesn’t process information in a linear, input-output fashion like a computer. Instead, the neocortex constantly makes predictions based on past experience and the Old Brain’s current sensory input. When predictions and inputs match, your neocortex strengthens its existing neural connections—such as when you judge how hard to toss a ball and it lands exactly on your target. When your neurons’ predictions are wrong, like when you miss when throwing a ball, your brain will form new neural connections to update its mental models of the world. This process of prediction and error correction is a fundamental aspect of how brains learn, and since all the neocortex’s information comes from the Old Brain, they have to work together to enable intelligent thought and decision-making.
(Shortform note: By showing that we learn new skills and information by engaging different regions of the brain at once, Hawkins backs up the arguments of educators who tout the value of teaching techniques that exercise multiple sensory pathways. In Learning How to Learn, Barbara Oakley and Terrence Sejnowski explain that, if you see and hear new information, your brain will create more neural connections. Likewise, in Limitless Mind, Jo Boaler writes that, when multiple parts of your brain interact [such as those that manage memory, language, and vision], you amplify your ability to incorporate new information. Since the Old Brain is the nexus for all these processes, our most primitive mental functions are crucial for higher learning.)
Sharma takes this understanding further by offering practical strategies for accessing higher cognitive functions despite ancient brain resistance.
Your task, Sharma contends, is to become aware of the tactics of the ancient brain so you can acknowledge them for what they are and ignore them. The only way to tap into your unique genius is by venturing into the unknown parts of yourself where strength, courage, and creativity reside. You must turn to what Sharma calls the Mastery Brain. Some scientists refer to this part of the brain as “the high mind” because it’s responsible for cognitive reasoning and analysis. Your creativity, productivity, and foresight live within this part of the brain.
Sharma cautions that you have a finite capacity for thought each day that gets used with each new activity you give your attention to. The more things you turn your attention to, the more diminished your capacity for thought becomes. And, when you start your day without intention, you’re essentially walking into the world like a magnet, ready to attract whatever distraction comes your way. You’ll have no mental capacity left by the end of it to give to internal reflection and growth.
The solitude and peacefulness of what Sharma calls the Victory Hour provide the space for you to sit with your fears and confront them, rather than let them run your life. When the world is quiet and devoid of distractions, you’re able to hear your inner voice and open yourself up to your strength and talent. Silence and tranquility activate your brain to produce the neurotransmitter dopamine (which sends pleasure signals to your nervous system) and serotonin (which improves mood). These chemical processes create the flow state.
Explore Further
Together, these perspectives reveal that the ancient brain isn’t an obstacle to overcome but an integral part of our neural architecture that requires understanding and skillful navigation. To learn more, read Shortform’s guides to the three books that these ideas come from:
- A Thousand Brains by Jeff Hawkins
- How to Create a Mind by Ray Kurzweil
- The 5 AM Club by Robin Sharma
