How many brains do you think you have?
One? Are you sure?
It seems obvious: “Everyone knows you have one brain, Ruben.”
And yes, that’s true—one brain, one nervous system. But here’s the twist: your brain isn’t a single, unified command center. It’s more like a committee of three, constantly bickering over what you should do, think, and feel.
Confused? Good. That’s exactly how I felt when I first learned about the Triune Brain Theory. But what if I told you that understanding this internal tug-of-war was the biggest breakthrough I ever had in understanding myself?
These “three brains” each have their own strengths, weaknesses, and priorities—and they rarely agree. That chaos you feel when you’re torn between eating the salad or devouring the chocolate cake? Blame the squabbling trio inside your head.
So, let’s dive in and meet your inner lizard, mammal, and human—and uncover how their constant battle shapes your life.
The Lizard Brain: The Dominant Survivalist
First on the scene is the lizard brain, the oldest part of your brain from an evolutionary perspective, responsible for survival instincts and automatic behaviors like heart rate, breathing, aggression, dominance, territoriality, and basic motor functions. We share this brain with lizards and birds, hence the name.
Its characteristics are reactive and habitual, focused purely on survival. This part of the brain does its own thing and takes over whenever it deems necessary—typically in survival situations or when you’re horny. If you’ve ever spent a bit too long underwater and felt the strong urge to surface and breathe, that was your lizard brain taking over. Any emotions or thoughts you had at the time were pushed aside; they no longer mattered.
How does this relate to wisdom, you might ask? Well, the lizard brain is responsible for sending you basic ‘urges’: the urge to eat, breathe, shit, fuck, and sleep. A wise person knows when to let the lizard brain do its thing and listens to it (most of the time). Are you hungry? Eat. Are you sleepy? Sleep, for god’s sake.
Now, you might think this is obvious, but you’d be surprised how many people ignore these urges and then complain they feel like crap. “No wonder, genius—you haven’t slept in two days. Maybe stop partying so hard and recover.”
Most conflicts with the lizard brain arise because we no longer live on the savannah but in modern civilization—a world filled with drugs, fast food, alcohol, and other irresistible temptations. Your lizard brain is wired for survival and, after millions of years of evolution, it assumes food is scarce. It will send you urges constantly to eat everything in sight. The same goes for narcotics; they tamper with your lizard brain’s biochemistry and fuel addiction. Take away the sugar, alcohol, or cocaine, and your lizard brain goes into panic mode.
I consider the entire brain essential, but if I had to rank them, this part is by far the most crucial. Without it, you’d be dead. You can survive without the others in a vegetative state, but without the lizard brain, there’s no life at all.
The Mammal Brain: The Master Motivator
The mammal brain governs emotions, memories, and social behaviors. It’s linked to bonding, nurturing, and the fight-or-flight response. It developed in early mammals, enabling emotional responses and the capacity for social attachments.
Its characteristics are emotional and intuitive, driving behaviors based on feelings and memory. I call this part of the brain the motivator, because it’s emotions—not thoughts—that drive behavior. Read that again; it’s important!
This was a hard lesson for me to learn. I believed my rational brain was in charge and tried to control, suppress, and ignore my emotions. Many people do this, especially men. It’s not wise—more on this later.
The mammal brain and lizard brain are connected neurologically, but for simplicity’s sake, it’s mostly the mammal brain reacting to the lizard brain, not the other way around. The lizard brain spots a predator, initiating the raw, automatic impulse to fight or flee. The mammal brain then steps in, adding an emotional dimension like fear, anxiety, or rage.
The mammal brain ranks second in terms of importance. Without it, you’d have zero motivation to do anything. Medical science has observed cases where this part of the brain was damaged, and the results are devastating. These people’s lives fall apart—they stop caring. T
he fascinating part is that they can explain what’s happening: “I should pick up my kids from school,” “I should go to work on time,” “My wife left me because I feel no love for her anymore.” You might think, “Well, if they know what to do, why don’t they just do it?” But it’s not that simple.
As I said before, it’s the emotional brain that motivates, and without motivation, behavior doesn’t happen.
Wise people understand this and learn to work with their emotions instead of against them. I’ll dive deeper into this later—it’s exciting and powerful stuff.
The Human Brain: The Savvy Creator
And finally, my favorite part of the brain: the human brain, also known as the neocortex. It’s the most recent development in mammals and is especially prominent in humans. This is the seat of higher cognitive functions like reasoning, language, planning, and abstract thought.
Its characteristics are rational and analytical, capable of reflective thinking. It’s what allows us to solve complex problems, create culture, develop technology, and advance science. It’s the part of us that is brilliant—it’s what took us to the moon, let us observe the universe, invent the internet, and build civilizations. It’s the part of the brain that is absolutely mind-blowing; it’s the source of wisdom.
You might have noticed I’m a bit biased—why is that? Well, guess which part of my brain is writing these words? Exactly, it’s the human brain.
And as you read this, your human brain is interpreting the words, while your lizard brain is preoccupied with survival (hungry, anyone?), and your mammal brain feels an emotion but doesn’t fully understand the words or concepts. It only understands feelings, and it’s probably feeling excited because you’re learning something new. How do I know this? Because if you weren’t excited, you’d have already stopped reading.
This distinction is crucial: it implies that your human brain is not in control, even though it loves to think it is. Arrogant bastard.
Earlier, I mentioned that the lizard brain does its own thing, and the mammal brain reacts to it. The human brain, in turn, reacts to the lizard and mammal brains, but rarely the other way around. Your human brain excels at knowing what to do: quit smoking, start exercising, study for the exam, work hard for the promotion, or ask that attractive girl out on a date. But despite this clarity, it often gets overruled by the other two. This is where things get tricky
The Clever Trickster: How Your Own Mind Works Against You
The following happens to all of us; the human brain becomes the toxic enabler of the deeper brains, it turns from a brilliant thinker into a clever trickster, working overtime to justify and rationalize the impulses of the reptilian and mammal brains.
It wraps our deepest fears and insecurities in layers of logic and excuses, convincing us that our avoidance is wisdom, our procrastination is just “taking a break,” and our self-doubt is merely realism.
And it can get ugly, fast. Here’s where the rationalizations turn into poison:
-You tell yourself: “I don’t deserve love because I’m not good enough,” when really it’s your mammal brain afraid of being hurt, clinging to safety.
-You think: “The world is a mess, so why bother trying?” when it’s your lizard brain overwhelmed by fear and seeking to shut down.
-You say: “If I fail, it’s because I never really wanted it anyway,” masking your deep-seated fear of rejection with fake indifference.
-You believe: “It’s everyone else’s fault I’m unhappy,” as your human brain deflects blame to protect your fragile sense of self.
But the most dangerous lies are the silent ones, the ones you don’t even realize you’re telling yourself:
-“I’m unlovable,” you tell yourself unconsciously, masking the deep fear that you’re broken beyond repair.
-“I’m stuck; I can’t change,” because the idea of facing the unknown is more terrifying than the comfort of familiar misery.
-“Nothing will ever get better,” as the lizard brain curls into a ball, too scared to hope.
-“I’m a burden,” you say to yourself, believing that your pain isn’t worth sharing, that your very existence is an inconvenience.
I have thought these thoughts -most of us have- but not all of us dare to admit it.
They are not harmless. They become anchors that drag you down, locking you into mental habits and mindsets that keep you from developing your wisdom. The irony is that the very part of your brain capable of higher reasoning and growth is used against you, hijacked to protect the parts that want nothing more than comfort, safety, and sameness—even if it means slowly suffocating you.
I am sorry for taking you on this emotional rollercoaster but it’s for the best, because here’s the good news: awareness is the first step to breaking free. By noticing when your human brain is making excuses for your deeper fears, you can start to reclaim control. This is the path to true growth and wisdom—not silencing the lizard and mammal brains, but learning to listen to them, acknowledge their fears, feeling their pain, and gently guide them into alignment with your true self.
It’s not easy. In fact, it’s the hardest work you’ll ever do. But it’s also the most important, because true wisdom—the kind that can transform your life— is worth striving for.
Distilling Wisdom from the Chaos
The first lesson here is not to blame your human brain—it’s trying its best, and it’s not at fault. But it is responsible. The key isn’t to control or suppress the other parts of your brain; it’s to learn how to work together with them. This is where true wisdom begins: through emotional regulation, building healthy habits, self-care, therapy, stepping out of your comfort zone, confronting your fears, experimenting, and embracing failure as a tool for growth.
Qualities like self-awareness, emotional intelligence, self-reflection, discipline, willpower, resilience, persistence, adaptability, patience, mindfulness, and a growth mindset are crucial on this journey.
By integrating these qualities, we cultivate a deeper understanding of ourselves, bridging the gap between our instincts, emotions, and rational thought. This harmonious relationship between the layers of our brain is key to developing wisdom, inner peace, and the capacity to thrive despite life’s challenges.
Disclaimer
I am aware this whole post is an affront to psychology and neuroscience. The Triune brain theory is a gross oversimplification of how the brain works, neuroimaging and evolutionary studies show that emotional and cognitive functions are not strictly confined to the limbic system and neocortex, respectively.
Modern science has a solid understanding of how nerve cells interact and the chemicals involved, as well as a good grasp of the functions of different brain regions and their evolutionary development.
What we lack, however, is a robust theory explaining how these chemical interactions at the cellular level give rise to our thoughts, perceptions, and what we visualize in the “mind’s eye.” We still cannot fully explain how the brain generates the subjective experience of thought or the essence of being human.
So despite its flaws, the Triune Brain Theory provides a memorable framework for understanding the brain’s evolution and its impact on behavior, and to me it remains an useful metaphor to understand myself and therefore I wish to pass it on to you.
