The sheer volume of neurons and synapses in the brain underscores its remarkable capacity for complexity and adaptability, making it one of the most sophisticated biological systems. Using an accessible approach to understanding how it works, you can harness its power to tackle long-term challenges, such as achieving personal finance success. This article begins with sensory input and explores how the brain processes information through its major systems, including memory, the limbic system, and the cerebral cortex. Generative AI (GenAI) serves as a modern example of how technology augments these processes, complementing the brain’s analytical capabilities while requiring human guidance to ensure context and prevent bias.
The article highlights the distinct yet interactive roles of the two hemispheres of the cerebral cortex, guided by emotion tags and shaped by the dynamic interplay between neurons, synapses, and neurotransmitters. You will learn how cognitive biases rooted in our neurobiology influence everyday choices, including personal finance decisions, and why our brains naturally resist long-term thinking. Drawing on insights from neuroscience and psychology pioneers like Jill Bolte Taylor and Daniel Kahneman, the article connects brain science and cutting-edge AI to practical, real-world decision-making applications. Whether you want to understand your decision-making habits, explore the potential of GenAI, or unlock neuroplasticity to change them, this journey through the brain will leave you thinking—and feeling—differently.
About the author: Jeff Hulett leads Personal Finance Reimagined, a decision-making and financial education platform. He teaches personal finance at James Madison University and provides personal finance seminars. Check out his book -- Making Choices, Making Money: Your Guide to Making Confident Financial Decisions.
Jeff is a career banker, data scientist, behavioral economist, and choice architect. Jeff has held banking and consulting leadership roles at Wells Fargo, Citibank, KPMG, and IBM.
Table of Contents:
Introduction Explore how a simplified model of the brain's 86 billion neurons and 100 trillion synapses provides insights into behavior, decision-making, and long-term thinking.
How the Emotion Tag Gets Built This section explores how neurons, synapses, and neurotransmitters dynamically adapt through neuroplasticity, enabling communication, habit formation, and learning.
Brain Pathway Examples Examine three contrasting cases of brain pathways—high emotion with low language and low emotion with high language—to understand how the brain prioritizes actions.
Cognitive Bias Discover how cognitive biases, rooted in our evolutionary shortcuts, influence decision-making and why they often lead to systematic errors in judgment.
Navigating Brain Balance with Jill Bolte Taylor Examine the vital oversight role of the right hemisphere and its growing importance in the age of advanced technology like GenAI.
Conclusion Summarize how understanding the brain’s mechanics helps us navigate biases, adopt better decision-making strategies, and unlock personal growth.
Notes Delve into the references, additional context, and resources that support and expand upon the key ideas discussed in the article.
1. Introduction
With approximately 86 billion neurons, over 100 trillion synapses, and evolutionary development spanning hundreds of millennia, this model is as simplified as it gets. [i] I condensed it onto a single slide to distill its essence. The most important takeaway from this representation is that the brain is both highly interactive and dynamic. While distinct functional centers exist, understanding any single brain function requires seeing how it connects to and interacts with the whole. [ii] The next graphic offers a simple yet powerful visualization of these complex processes.
My ability to specify this model has evolved as informed by the thinking of others. Thanks to work by Daniel Kahneman, Iain McGilchrist, Albert Einstein, Jill Bolte Taylor, George Dyson, Charles Darwin, Richard Dawkins, Robert Sapolsky, Douglas Hofstadter, Stanislas Dehaene, Chantel Prat, and others. A special mention goes to Jill Bolte Taylor. She is the only brain scientist I know who has explored her own brain firsthand. Dr. Jill did this as a result of a stroke. Her personal narrative of her journey is remarkable. Her book is called My Stroke Of Insight.
This model introduces the concept of an "emotion tag"—a layer of information that enhances "flat" sensory input with emotional weight. Jill Bolte Taylor's insight, "Most of us think of ourselves as thinking creatures that feel, but we are actually feeling creatures that think," underscores this idea. Dr. Jill, a Harvard-trained neuroscientist, offers a unique perspective on brain function based on her personal experience of a massive stroke. Her personal narrative offers remarkable insights into how the brain handles emotion, memory, and sensory input, emphasizing the significant influence of information context on our emotions and our view of the world.
Our understanding of the world is initiated through the lens of emotion-based processing, as our five senses feed data into the brain. Please see the prior "Brain Process Model" graphic. You may follow sensory information's path through the model, from left to right. The intensity of the emotion tag plays a critical role in guiding this information along different mental processing paths. High-intensity tags often activate the right hemisphere, which excels at processing multiple inputs simultaneously and operates in the present moment. In contrast, low-intensity tags favor the left hemisphere, which processes information serially, connecting past and present to make predictions about the future. Each hemisphere contributes uniquely to how we experience and interpret the world.
The tagging concept aligns with research on decision-making and demonstrates how sensory input flows through various mental pathways based on the degree of emotional tagging. [iii] While pathways differ in intensity, all are generally engaged to some extent, making behaviors influenced by these processes probabilistic rather than deterministic. In practice, emotion tags activate complex networks of neurons, synapses, and neurotransmitters that collaborate to process information and drive decisions. These intricate pathways illustrate how the brain integrates emotion and cognition, setting the stage for behaviors that range from instinctive reactions to deliberate actions. Emotion tagging thus offers a powerful framework for understanding the interplay between feeling and thinking in our daily lives.
2. How the emotion tag gets built
Before discussing the brain pathway cognitive process, it is important to explore the essential building blocks. Every cell in the human body, including neurons and other body cells, contains DNA. DNA acts as the universal blueprint, providing instructions on how each cell should function. For example, in spleen cells, DNA guides the cells to perform tasks critical to the spleen's role in filtering blood and supporting immunity. In neurons, DNA governs the formation of structures and mechanisms required for processing and transmitting signals. While neurons specialize in communication, other cells primarily build and maintain the specialized functions of their respective organs or systems.
The neuron count, a feature of the human genome, is largely fixed not long after birth. Most humans are endowed with an astounding number of neurons early in life, typically around 86 billion. Each neuron forms about 1,000 or more connections, known as synapses, with other neurons. The volume of synapses may exceed 100 trillion in a single brain. However, unlike neurons, which are more static, synaptic development is dynamic and changes throughout life in response to environmental demands—a process known as neuroplasticity. Synapses grow or are pruned depending on how often they are used, allowing the brain to adapt to new experiences or let go of unused pathways.
Think of neurons as the genetic gift passed down from our ancestors, forming the foundation of our learning. Synapses, in contrast, are the adaptive gift of our environment, enabling us to fine-tune this foundation based on our individual experiences. [iv-a]
Interestingly, a synapse is not a physical thing but a space—a tiny gap between neurons where communication occurs. When an electrical signal travels down a neuron’s axon, it cannot directly pass to the next neuron. Instead, neurotransmitters are released into the synaptic cleft—the space between neurons—where they bind to receptors on the neighboring neuron. This biochemical interaction transforms the electrical signal into a chemical message, bridging the gap and enabling communication.
The process of passing information from one neuron to another is not perfect. It is a bit like the childhood game of Telephone, where a whispered message travels around a circle and often emerges differently by the end. Similarly, the information passed through synapses can change slightly as it moves through a neural network. This variability contributes to the flexibility and adaptability of the brain but can also lead to subtle distortions in signal transmission.
The human brain, including its neurons and synapses, is one of the most complex systems known to man—and it all operates within our own heads! Each neuron has three main parts:
The nucleus: Produces the bioelectrical signal that travels to neighboring neurons.
The axon: Transmits the signal from the nucleus to the next neuron.
The dendrite: Receives signals from neighboring neurons and passes them to the nucleus.
The nucleus functions as a simple binary switch, but the true complexity arises from the immense number of neurons and their connecting synapses.
In the axon, vesicles release neurotransmitters into the synaptic cleft—or space—allowing signals to pass to the dendrite of the next neuron. This release occurs when the neuron reaches an "action potential" threshold of about -55 millivolts. Action potentials—electrical impulses that send signals through your body—represent temporary shifts in the neuron’s membrane potential, where the inside briefly becomes less negative due to ion movement. The type of neuron and its connections to others determine which neurotransmitter is released. A remarkable feature of the brain is its ability to modify these pathways through neuroplasticity, enabling the formation of new habits and the adaptation to changing environments.
Thus:
Changing habits -> changing neuron types -> changing neurotransmitter concentration
On the other side of the synapse, the neighboring neuron’s dendrite hosts receptors. These receptors act as locks, with neurotransmitters serving as keys. Only when the correct neurotransmitter binds to its receptor is the signal passed along. Neurotransmitters that fail to bind are reabsorbed, broken down, or discarded. This receptor "lock" serves as a critical control point in neural communication, ensuring that only the right signals continue through the network. Individuals vary in their receptor distribution; for example, someone with more dopamine receptors may find extroversion-based rewards more motivating, while someone with more acetylcholine receptors may favor introversion-based rewards.
Neurotransmitters can either excite (encourage action potential firing) or inhibit (discourage firing) a neuron. For instance, dopamine and acetylcholine are excitatory, promoting neural firing. Inhibitory neurotransmitters, like serotonin and GABA, work to calm the system, balancing excitatory signals. For example, serotonin’s calming effect can help counteract excitatory dopamine, aiding in sleep and relaxation.
As learning is reinforced by environmental feedback, the pre- and post-synaptic connections involved in that learning increase in size and number. This aligns with Hebbian Learning, introduced by Donald Hebb, who famously stated, "Neurons that fire together, wire together." [iv-b] This principle explains how repeated activation strengthens neural connections, making them more efficient. Conversely, unused synapses weaken and are pruned over time, creating space for new, more relevant pathways. Hebbian Learning illustrates how the brain fine-tunes its networks, supporting both the development of long-term habits and the acquisition of new skills.
Synaptic adaptability, combined with the lock-and-key mechanism of neurotransmitters, allows the brain to respond dynamically to our thoughts, experiences, and environment. The next graphic provides an example, focusing on two reward neurotransmitters—acetylcholine and dopamine—but it is important to note that many other neurotransmitters contribute to this intricate process.
For an example of neurobiology and neurotransmitters, please see: How our neurobiology impacts our life's pursuits: Are you from 'Dope-land' or 'Acetyl-ville?'
3. Brain Pathway Examples
Section 2 provided a survey of how our brain operates. It would be nice if we could actually see what is going on in our brain—but alas, we cannot. Even if we had access to the most modern fMRI, PET, or EEG equipment, these technologies do not truly see how the brain operates; they only infer brain activity by measuring proxies such as blood flow, electrical signals, or chemical tracers. [v-a] This limitation is akin to the blind men and the elephant parable, where each blind man perceives only a portion of the elephant and thus forms an incomplete understanding of the whole. However, these tools provide a solid foundation for exploring the immense complexity of our brain, offering valuable insights that, when combined, contribute significantly to our growing understanding of this remarkable organ. [v-b]
This section bridges the mechanical discussion of the brain in Section 2 with examples that illustrate how different pathways present themselves in our everyday experiences. A key structure that facilitates communication between the brain's two hemispheres is the corpus callosum, a dense band of nerve fibers connecting the left and right sides of the brain. The corpus callosum acts as a superhighway, enabling rapid information exchange between the hemispheres and coordinating their specialized functions. This integration allows us to experience a unified thought process, even as the right hemisphere excels in emotion-driven processing and the left hemisphere focuses on language and analysis. The pathways discussed here reflect this interplay, with the corpus callosum ensuring both hemispheres contribute to our responses, no matter which hemisphere dominates the situation.
To add some dynamism to the Brain Process Model, please consider three contrasting cases: first -- 'The high emotion tag & low language case,' the second -- 'The low emotion tag & high language case,' and the third -- 'The high emotion tag & low language case in Flow State.' These cases are extreme examples to demonstrate the brain's different pathways. [v-c] Remember, the brain is incredibly dynamic; even in these extreme cases, the brain is still fully engaged, just more in certain functions than others. Next, I will describe each case. Immediately following, I will show each case with a highlighted pathway overlay. These pathway examples are simplistic. The actual path exhibits more feedback loops and interaction.
1) The high emotion tag & low language case - Imagine one of those sleek, high-performance yachts with four powerful outboard engines waiting at a marina on the Atlantic or Pacific seaboard. When the captain slams all four throttles to maximum, the yacht launches forward with explosive speed, using every ounce of its power to surge ahead. This is what happens in your body when faced with extreme danger, like running from a lion—your neurotransmitters act as the engine throttles, unleashing their full force to fuel your survival.
You see the lion, and instantly, your brain recognizes the life-threatening danger. As depicted in the shaded model below, which highlights the pathways activated during such moments, sensory input from your eyes triggers your sensory memory in an instant. A high-intensity fear tag is placed on this input—much like the yacht's throttles being slammed to maximum—and routed directly to your right hemisphere [vi-a]. This rapid response illustrates the brain as a "prediction machine," instantly forecasting a catastrophic outcome—becoming a lion's next meal—and triggering swift action to avoid it. This response reflects the brain's evolutionarily older default process, which prioritizes rapid, emotion-based processing in the limbic system and right hemisphere.
The evolutionary design of the brain bypasses left hemispheric-based language processing in situations requiring immediate reactions, such as during a lion attack. This adaptation serves to:
Enhance Reaction Time: Quick, instinctive reactions are crucial for survival, allowing individuals to respond to threats without the delay that language processing would introduce.
Prioritize Survival: In life-threatening situations, the brain's focus shifts to immediate physical responses rather than verbal communication, increasing the chances of escaping danger.
Part of learning and adapting involves enhancing the availability of left-hemispheric processing, enabling the brain to interpret and respond to information beyond the instinctive, default pathways of the right hemisphere. The left hemisphere's evolutionarily younger capacity for language and analytical thought provides greater flexibility and depth in addressing complex, non-urgent situations. But certainly, as in the case of a lion attack, your slower left hemisphere is being bypassed to maximize the chance of survival.
Returning to our "run from the lion" story -- at the same time, your brain triggers the release of key neurotransmitters to amplify your physical and mental reactions. Adrenaline (epinephrine) and noradrenaline (norepinephrine) flood your synaptic clefts, heightening alertness, focus, and energy for immediate action. Glutamate, the brain's primary excitatory neurotransmitter, intensifies neural signaling to ensure rapid responses. Additionally, dopamine may play a role in enhancing goal-directed action, such as prioritizing escape. Hormones like cortisol sustain your heightened state, while endorphins may suppress pain, allowing you to maintain peak performance. These neurotransmitters and hormones work together to create a highly efficient survival response optimized for speed, power, and focus.
This cascade of neurochemical activity is the result of millennia of evolution, fine-tuning our ability to respond instantly to life-threatening situations. Running from lions was undoubtedly a priority in the natural selection process, ensuring the survival of our ancestors and the ingraining of this swift, high-emotion, low-language pathway in our genome.
Social Media and the Brain
Interestingly, this same neurochemical system is often targeted by social media. Platforms engage emotions—frequently through fear, excitement, or anxiety—while leveraging dopamine's addictive properties to elicit right-hemisphere-dominant reactions. This can prompt impulsive actions without input from the left hemisphere or related executive control functions, underscoring the need for mindfulness in navigating such stimuli.
The Importance of Emotion Tags
The nature of the emotion tag plays a critical role in shaping brain responses. Negative emotions like fear and anxiety create different neural impacts compared to positive emotions such as happiness and fulfillment. For more on how these pathways influence choices, see The Anatomy of Choice: Learning from a Brain Explorer.
Executive Control and Age
Our executive control functions, located in the prefrontal cortex and associated with the left hemisphere, are vital for regulating impulsive reactions and making complex decisions. However, these functions do not fully mature until the mid-twenties, highlighting the importance of caution in making significant life choices at a young age.
It is perplexing that in the United States, teenagers can drive at 16 and commit to potentially life-altering college debt at 17, despite their brains not being fully equipped for such decisions. Interestingly, car insurers recognize this reality, which is why premiums are significantly higher for drivers under 25!
While the high-emotion case of running from a lion demonstrates the brain’s ability to prioritize immediate survival, other scenarios reflect the opposite end of the spectrum, where calm, deliberate processing takes precedence. Consider the example of learning neuroscience—a low-emotion, high-language case that engages entirely different pathways.
2) The low emotion tag & high language case - You are reading about neuroscience, delving into how different neurotransmitters are initiated in the brain's limbic system and other regions. These neurotransmitters function like color hues, combining in various ways from a few primary types to create an almost infinite array of effects. You reflect on how these combinations have influenced your past experiences and how they might shape your future decisions. Behavioral economics connects this understanding to decision-making, illustrating how our unique neurobiology, combined with habits and environmental influences, forms the foundation for our diverse rationality. [vi-b]
This recognition empowers you to realize that, while you cannot control every aspect of your neurobiology, you can shape how it is expressed through intentional habits and thoughtful environmental design. By applying this understanding to personal finance, you can create systems and strategies that align with your neurobiology, fostering long-term habits that build a lifetime of wealth. You feel calm, engaged, and satisfied with the process of connecting this knowledge to your daily life.
See the model below, a shaded version of the earlier model, with the pathways highlighted. Your eyes provide sensory input, activating your long-term declarative memory, with a low-intensity tag placed on the sensory input. This signal is routed to your left hemisphere, where connections are made between the past and future, and cognitive-based analysis is processed. The process is slow and deliberate, involving significant language processing. The complete integration of this learning might require several days or more, with sleep being crucial in aiding your brain to consolidate and store new information, and facilitating the transfer of this information to accessible long-term, declarative memory.
Yet, learning neuroscience is not solely about reading from a book. It may involve practicing in a clinical setting or receiving expert feedback—both of which deepen understanding through connection and active engagement. As Matt Beane suggests, mentorship and interpersonal connection are critical components of learning, as they activate neurobiological pathways that reinforce and refine understanding. [vi-c] Neurotransmitters enable connection, and in this case, oxytocin takes center stage, fostering trust and openness that make feedback and learning more impactful. This interpersonal dimension transforms abstract knowledge into actionable skills, facilitating the transition of declarative memory into procedural memory over time.
At the neurotransmitter level, dopamine reinforces your curiosity and motivates your pursuit of new knowledge, rewarding the process of discovery. Acetylcholine sharpens your attention and supports memory formation, allowing you to focus on the content and encode it for later retrieval. Glutamate, the primary excitatory neurotransmitter, strengthens synaptic connections, facilitating long-term learning and neuroplasticity. Serotonin helps maintain emotional balance and a calm, focused state, creating an optimal environment for thoughtful analysis. A moderate release of cortisol, triggered by mild stress, can enhance focus and attention by increasing alertness and facilitating short-term memory retrieval—providing just enough stress to sustain your curiosity without overwhelming your cognitive capacity. Additionally, brain-derived neurotrophic factor (BDNF) supports synaptic plasticity and the growth of neural connections, enhancing your brain's ability to adapt and learn over time.
Together, these neurotransmitters, hormones, and neuromodulators create the conditions for curiosity-driven exploration and sustained learning, empowering you to connect new insights with prior knowledge and integrate them into your understanding of the world. Through connection, practice, and reinforcement, learning becomes more than a cognitive exercise; it transforms into a deeply integrated and actionable part of who you are.
In our next case, the flow state is introduced. This represents the culmination of learning, where deliberate practice and understanding are transformed into instinctive, rapid action. While the previous case emphasized the left hemisphere’s role in acquiring and refining complex skills, this case shifts those learned abilities into the high-emotion, low-language pathways of the right hemisphere. This transformation enables the brain to bypass slower analytical processes, allowing for seamless, intuitive responses to challenges that demand immediate action.
3) The high emotion tag & low language case in Flow State - Imagine a seasoned fire captain in the midst of a house fire, navigating an environment where split-second decisions mean the difference between safety and disaster. Surrounded by roaring flames, falling debris, and urgent radio calls, the captain must act instinctively, responding to the situation with precision and speed. In this moment, there is no time for deliberation; his brain engages the high-emotion, low-language pathway, enabling rapid, life-saving decisions fueled by years of training and experience.
In a flow state, sensory input—such as the crackle of flames, shifting sounds of weakened beams, or the intense heat of the fire—is tagged with high emotional intensity. This information bypasses the slower, language-based analytical processes and flows directly through the limbic system to the right hemisphere for immediate, instinctive action. As depicted in the shaded model below, the high-emotion, low-language pathway activates the brain’s evolved capacity for fast, decisive responses in high-stakes situations.
While the left-hemispheric low-emotion, high-language pathway is essential for learning and deliberate problem-solving, flow state relies on procedural memory, which is cultivated through repeated practice and experience. Years of deliberate preparation transform episodic memories of firefighting scenarios into automatic responses stored in procedural memory. These instincts are then readily available to guide action during moments of crisis.
In the fire captain’s flow state, a finely tuned cocktail of neurotransmitters orchestrates the brain’s performance. Dopamine plays a central role, delivering a sense of reward and motivation that keeps him locked into the task, celebrating each accurate decision as it happens. Norepinephrine surges through his system, heightening his alertness and energy, allowing him to track multiple sensory inputs simultaneously and respond dynamically to the evolving chaos.
At the same time, endorphins dull the physical discomfort of heat and exhaustion, ensuring he can sustain peak performance despite the taxing environment. Anandamide flows in, fostering creativity and lateral thinking, enabling the captain to adapt quickly and devise innovative solutions to unexpected challenges. Serotonin quietly stabilizes his mood, creating a calm yet alert state that balances the intensity of the moment, helping him maintain composure amidst the crisis.
Together, these neurotransmitters create a state of seamless action, where every movement and decision feels effortless and instinctive, yet precisely aligned with the demands of the situation. Please notice, that the flow state mix of neurotransmitters has some differences from the first high-emotion case. The changed mix helps to integrate intuitive procedural knowledge provided by long-term memory.
Amid the chaos of the fire, the captain calls out, “Focus on the south wall!” His team executes the order, trusting his expertise. Moments later, feeling an impending danger he cannot articulate, the captain orders an immediate evacuation. As the firefighters exit, the building collapses behind them, narrowly avoiding catastrophe. When asked afterward why he made the life-saving decision, the captain responds, “I don’t know—it just felt right.” This illustrates the essence of the flow state: years of preparation transformed into instinctive action, enabling life-saving decisions without conscious deliberation.
Memory Systems in Flow
Unlike the immediate sensory memory used in “running from the lion” or the declarative memory employed when learning neuroscience, flow state depends on procedural memory. Procedural memory, refined through repetition and practice, stores automatic responses that can be accessed rapidly without conscious thought. While episodic memory plays a critical role during the learning phase, it is procedural memory that allows the fire captain to act decisively, leveraging ingrained instincts to navigate the crisis. This distinction in memory systems is fundamental to understanding how flow state enables fast, effective action.
Flow state is not unique to emergency responders. Athletes competing in high-stakes moments, surgeons performing delicate operations, and musicians improvising on stage also access this state of heightened focus and performance. Each example highlights the brain’s remarkable capacity to align preparation and instinct, making flow a pinnacle of human achievement. [vi-d]
An important next-level question is—if we have the choice of different pathways, how does our brain decide which path it follows? This is a question of attention. As discussed in the first two examples, if you happen to be learning about neuroscience when a threatening lion approaches, it is certainly hoped that running from the lion would be the priority! While learning neuroscience may be interesting, running from the lion will keep us alive! This is likely to happen because of our evolutionary 'stayin' alive' conditioning. But you can imagine many other less obvious cases, such as deciding whether to save money today or spend it on a night out with friends. This scenario highlights the tension between immediate gratification and long-term planning—a mental tug-of-war that mirrors how we allocate our attention across competing priorities.
Your brain in this personal finance scenario is like a boat with multiple throttles. Dopamine and oxytocin push the throttle forward for the engines driving immediate gratification, increasing the emotion tag that makes spending now feel more rewarding. Acetylcholine, on the other hand, acts like the throttle for an engine steering the boat in a different direction—the rewards of curiosity and focused decision-making—helping to guide attention toward long-term goals like saving. Serotonin works like a stabilizer, gently pulling back on the throttles to moderate speed, ensuring the boat doesn’t veer off course or burn out from impulsive decisions. Commitment devices, like automated savings plans, serve as the navigation system, keeping the boat steady on its intended course, even when short-term rewards create natural attention conflicts. These conflicts lie at the heart of why saving money can feel so challenging for many people. Everyone’s attentional starting place, shaped by their unique attention-weighting factors, is different. As discussed, the brain’s default, evolutionarily older pathways emphasize quick, emotion-driven processing, making socializing with friends the more intuitive choice. Overcoming this default to prioritize saving money requires intentional effort and strategies.
As a personal finance professor, part of my goal is to influence students' attention circuitry to encourage saving money and other behaviors that drive long-term wealth. I understand the challenge, though—I am competing against short-term distractions that may feel more rewarding in the moment!
Also, there are far more things we can attend to via our senses than we could possibly attend to at once. So prioritizing our attention is a critical function of our brain.
Next are the key attention-weighting factors:
Neurotransmitter Activity: Neurotransmitters like dopamine and acetylcholine play critical roles in regulating focus and attentional control.
Dopamine: Enhances motivation and goal-directed behavior, helping maintain focus on rewarding tasks.
Acetylcholine: Supports sustained attention and the ability to filter out distractions.
Cognitive Flexibility: The brain's ability to flexibly allocate attention to relevant stimuli, while suppressing irrelevant ones, is influenced by neural wiring and efficiency. This can vary significantly between individuals based on their unique neurobiology.
Hemispheric Specialization: Attention is also driven by how the left and right hemispheres divide and coordinate tasks. For example, the right hemisphere is more involved in broad, global attention, while the left hemisphere specializes in fine-tuned, focused attention. While we all have similarities in how the left and right hemispheres operate separately, how those hemispheres operate together is intensely personal.
4. Cognitive Bias
Cognitive biases emerge as the brain navigates uncertainty, making decisions based on limited information. While decisions may seem logical given the moment, these biases reveal how incomplete information and perception influence outcomes. To understand cognitive biases, it is important to first discuss heuristics—the mental shortcuts our brains use for quick action. Behavioral psychologists often refer to high emotion tag and low language-based brain decisions as heuristics because they enable fast, instinctual responses to immediate challenges. These mental shortcuts are incredibly helpful, allowing us to react quickly in critical situations. In fact, heuristics are what helped our ancestors know when to run from the lion. Without them, you might not be here to read this today!
Think of a cognitive bias as the flip side of the heuristic coin. While heuristics prioritize speed and efficiency, cognitive biases are systematic errors in thinking that occur when we process and interpret information, often leading to flawed decisions or judgments. A high-emotion tag enables rapid action but sacrifices some accuracy to prioritize immediacy. Even in the flow state, we rely on the precision of well-trained procedural memory, but as poet Sarah Kay reminds us, 'Practice does not make perfect, practice makes permanent.' This highlights the importance of regular updates to training, as outdated or incomplete procedural memory can still lead to errors, allowing cognitive biases to persist despite expertise.
There is a rich literature on the interplay of cognitive biases and heuristics. Daniel Kahneman and Amos Tversky’s classic Judgment Under Uncertainty is an excellent source for understanding these concepts. Cognitive biases also pose challenges in everyday life. For instance, cognitive biases impacting personal finance are:
Time Discounting Bias - preferring immediate gratification over long-term financial goals
Procrastination Bias - delay in completing an important task
Confirmation Bias - retaining selective information that confirms existing beliefs
Availability Bias - over-weighting immediate, easy-to-perceive information at the expense of under-weighting longer-term, harder-to-perceive information
It is no wonder then why 1) savings must be intentional, and 2) the U.S. has a very low retirement saving rate! Our own brains are naturally NOT wired for long-term savings.
The next graphic is a cognitive bias model for decision-making.
5. Navigating Brain Balance with Jill Bolte Taylor
With insights from Jill Bolte Taylor, Albert Einstein, Douglas Hofstadter, and a comparison to Generative AI, we will explore the powerful oversight role of the right hemisphere—an influence only increasing with technologies like GenAI. These perspectives illuminate how the hemispheres interact dynamically, with the right hemisphere guiding context and meaning while the left hemisphere handles logical and analytical tasks.
The experiences of neuroscientist Jill Bolte Taylor provide a fascinating lens through which to understand the brain’s dynamic nature. During a stroke, Dr. Jill observed firsthand how her brain’s right hemisphere functioned as her left hemisphere intermittently went offline. Her account offers unique insights into the roles of the two hemispheres, particularly in how they process emotions and maintain our perception of self. Below, her descriptions are broken into subsections, with summaries linking her observations to the themes of this article.
Losing Sensory Boundaries
"Imagine, if you will, what it would feel like to have each of your natural faculties systematically peeled away from your consciousness. First, imagine you lose your ability to make sense of sound coming in through your ears. You are not deaf, you simply hear all sound as chaos and noise. Second, remove your ability to see the defined forms of any objects in your space. You are not blind, you simply cannot see three-dimensionally, or identify color. You have no ability to track an object in motion or distinguish clear boundaries between objects. In addition, common smells become so amplified that they overwhelm you, making it difficult for you to catch your breath. No longer capable of perceiving temperature, vibration, pain, or proprioception (position of your limbs), your awareness of your physical boundaries shift. The essence of your energy expands as it blends with the energy around you, and you sense that you are as big as the universe."
Summary: Dr. Jill’s loss of sensory integration highlights the vital role of the brain in organizing and filtering sensory input. Without the left hemisphere’s structured processing, the boundaries between self and the environment dissolve. This ties back to the concept of emotion tagging, as sensory input without structure can create overwhelming emotional responses or lack of coherence.
Silencing the Inner Voice
"Those little voices inside your head, reminding you of who you are and where you live, become silent. You lose memory connection to your old emotional self, and the richness of this moment, right here, right now, captivates your perception. Everything, including the life force you are, radiates pure energy. With childlike curiosity, your heart soars in peace, and your mind explores new ways of swimming in a sea of euphoria."
Summary: Here, Dr. Jill describes how the left hemisphere, responsible for maintaining identity and personal narrative, goes offline. This allows the right hemisphere, which processes emotions and experiences in the present moment, to dominate. The idea of “being present” reflects the right hemisphere’s strength in managing high emotion tags, as seen in the earlier example of the lion chase.
Questioning Routine Motivation
"Then ask yourself, how motivated would you be to come back to a highly structured routine?”
Summary: Dr. Jill’s reflection underscores the tension between the left hemisphere’s structured, future-focused orientation and the right hemisphere’s expansive, present-focused awareness. It demonstrates how shifts in brain activity can influence behavior, motivation, and decision-making—a key consideration in understanding the dynamic interplay of brain pathways.
Linking Back to the Model
Dr. Jill's observations validate the themes of this article: the brain is a highly dynamic system where hemispheres interact to process emotion, memory, and sensory input. Her experience also illustrates the profound role of emotion tags and how their intensity can shape our perception of reality.
Generative AI provides an intriguing parallel to the brain’s processing dynamics. While AI excels at rapid, detailed analysis, its outputs require human oversight to ensure they align with broader contexts and nuanced goals. Similarly, in the brain, the interplay between emotion-based processing and the rational, analytical functions of the cerebral cortex is critical for making decisions that are not only efficient but also meaningful and adaptive. Just as our brain’s systems work together to filter, prioritize, and refine sensory input, we guide and refine AI to ensure it produces results that are not only accurate but ethically sound and contextually relevant. This partnership between technology and cognition demonstrates the importance of balance between speed and accuracy, as well as logic and meaning. Please see the article:
As the model suggests, the emotion-based limbic system receives information via our nervous system (and brain stem). It is our emotions that first react to sensory information. Our cerebral cortex, in either the left or right hemisphere, regulates and processes limbic-based information. A clarifying point is necessary for the limbic system. While it is true that it processes emotion, I am also lumping the basal ganglia into the limbic system function, although it is not anatomically part of the limbic system. Like the limbic system, the basal ganglia functions in a way that provides context for guiding cerebral cortex processing. As Chantel Prat describes, this is like an "if-then" logic statement, where the cerebral cortex handles the heavy lifting after the "then" part of the statement. [vii] In contrast, the limbic system-aligned basal ganglia handle the context-setting to direct attention and provide information resources to the cerebral cortex. Thus, the basal ganglia function as the "if" part of the statement.
Author Bob Samples’ study of Albert Einstein reveals: "Albert Einstein viewed the intuitive mind as a sacred gift and the rational mind as a faithful servant." Consistent with Dr. Prat's "If-then" analogy, the limbic system is the sacred gift, and the cerebral cortex, especially the left hemisphere, is the rational mind.
In the Pulitzer Prize-winning book, Goedel, Escher, Bach, the author, Douglas Hofstadter, makes the comment:“Apparently the master wants to get across the idea that (Zen) enlightened state is one where the borderlines between self and the rest of the universe are dissolved." Jill Bolte Taylor’s experience validates the notion of enlightenment as a right hemisphere endeavor and as necessary to quiet the left hemisphere. This could represent the paradoxical "dualism" of enlightenment, that is, "learning without learning" or "thinking without thinking."
6. Conclusion
Understanding the brain’s intricate processes through a simplified model offers powerful insights into how we think, feel, and make decisions. From the emotion tags that guide our immediate responses to the cognitive biases that shape our long-term planning, this framework connects the biology of the brain to the complexities of everyday life. While the brain’s capacity for adaptation through neuroplasticity highlights its remarkable potential, it also reminds us of the challenges inherent in overcoming ingrained habits and biases. By applying this knowledge, we can make more deliberate choices, embrace lifelong learning, and unlock the tools necessary for both personal and collective growth. Whether in personal finance, relationships, or careers, understanding how our brains work helps us navigate life’s uncertainties with greater clarity and purpose.
Undoubtedly, this brain model has applications across almost all aspects of our lives. In my corner of the world, I apply it to Personal Finance. Understanding the challenges of Personal Finance as first and foremost a behavioral challenge generated from how our brain works is the foundation for a lifetime of financial success. I am the founder and president of Personal Finance Reimaged. Our mission provides a consistent, repeatable decision process for a lifetime of wealth and health. For our books, videos, classes, and technology -- please see our website:
7. Notes
[i] Literature reviews suggest the number of neurons in the human brain is reasonably well known, at approximately 86 Billion. The number of synapses is less well-known. 100 Trillion seems to be a starting number, with some estimates suggesting well into the quadrillions. Part of the challenge of measuring synapses is agreeing upon what a synapse actually is!
Herculano-Houzel, S. (2009). "The human brain in numbers: A linearly scaled-up primate brain." Frontiers in Human Neuroscience, 3(31). doi:10.3389/neuro.09.031.2009
To provide relative size context for your neurons and synapses. Let’s say you could rent the synapses found in your brain for $1 / synapse. How much would it cost to rent all the synapses found in your brain? It would cost about 1.5x the annual economic output of the entire earth (2017, nominal GDP in US$).
[ii] As Hofstadter says in his book Godel, Escher, Bach “the most naive assumption that there is a fixed group of neurons for each concept (functional center)-is almost certainly false.” Steven Rose in The Conscious Brain and in reference to neurologist Karl Lashley‘s memory experiments: “So far as memory was concerned, the cortex appeared to be equipotential, that is, with all regions of equal possible utility.”
[iii] Finucane et al., The Affect Heuristic in Judgments of Risks and Benefits, Journal of Behavioral Decision Making, 13, no. 1 (2000): 1-17.
Finucane describes tagging as:
“The basic tenet in this paper is that images, marked by positive and negative affective feelings, guide judgment and decision making. Specifically, we propose that people use an affect heuristic to make judgments. That is, representations of objects and events in people's minds are tagged to varying degrees with affect.”
[iv-a] I do want to qualify the observation that "neurons are for 'nature' as handed down by our ancestors" and "synapses are for 'nurture' as generated within our lives." As usual, when it comes to the brain, this is a practical simplification that is correct on average, but certainly has nuance and exceptions.
Neurogenesis (the creation of neurons after we are born) does happen sometimes. Also, synaptic self-assembling occurs within our brains, when we are in the womb or after our birth, are the result of our legacy genomic blueprint. Thus, the "nature vs. nurture" line is gray when it comes to neurons and synapses. However, neurons ARE certainly a powerful legacy of natural selection occurring from our ancestors. Synapses DO help us update learning within our lives.
[iv-b] Hebb, D. O. (1949). The Organization of Behavior: A Neuropsychological Theory. Wiley.
[v-a] "Exploring the Frontiers of Neuroimaging: A Review of Recent Advances." Life, vol. 13, no. 7, 2023, p. 1472. doi:10.3390/life13071472.
[v-b] Saxe, John Godfrey. The Blind Men and the Elephant. 1872.
Just as the blind men’s understanding of the elephant depends on the part they touch, modern brain imaging technologies offer glimpses into neural processes, but no single tool captures the brain’s full complexity.
[v-c] Neurotransmitter reward pathways are also associated with personality typing. In general, introverts favor the acetylcholine-based pathway associated with the "The low emotion tag & high language case." Extroverts favor the dopamine-based pathway associated with the "The high emotion tag & low language case."
Hulett, Creativity - For Both Introverts and Extroverts, The Curiosity Vine, 2022: Please see section 2 "Neurotransmitters and Personality."
[vi-a] Camina, Guell,The Neuroanatomical, Neurophysiological and Psychological Basis of Memory: Current Models and Their Origins, Frontiers in Pharmacology, 2017
Hulett, Dreams are a window to our memories and healthy thinking, The Curiosity Vine, 2022
[vi-b] Hulett, Jeff. "Becoming Behavioral Economics: The Social Science Revolutionizing Decision-Making." The Curiosity Vine, November 7, 2023.
[vi-c] Beane, Matt. The Skill Code: How to Save Human Ability in an Age of Intelligent Machines. Harper Business, 2024.
[vi-d] Hulett, J. (2020, November 10). Soccer Brain - The Making of the Beautiful Game. The Curiosity Vine.
[vii] Prat, Chantel. The Neuroscience of You: How Every Brain Is Different and How to Understand Yours. Dutton, 2022.
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