Michelle: You know that idea of a 'normal' brain? The one we all secretly compare ourselves to? Mark: Oh, I know that feeling. The one that’s perfectly focused, always optimistic, never forgets a name… Michelle: That one. Well, it's a myth. According to neuroscientists, there is no such thing. The average brain is a statistical fiction, and trying to be 'normal' might be the most abnormal thing you can do. Mark: Whoa. Okay, that's a bold start. So all my anxieties about not being 'normal' are… pointless? Michelle: Beautifully pointless. And that's the radical idea at the heart of The Neuroscience of You by Chantel Prat. Mark: Chantel Prat... she's a pretty big deal in the neuroscience world, right? A professor who's known for challenging these one-size-fits-all ideas about the brain. Michelle: Exactly. She's a cognitive neuroscientist at the University of Washington, and her whole career is built on studying individual differences. She wrote this book, which has been widely acclaimed, not as a dense textbook, but as a guide for the rest of us to understand our own, unique brain wiring. She wants to make neuroscience personal. Mark: I like that. Taking it out of the lab and putting it into our lives. So where does she even begin with an idea that big? Michelle: Her starting point is this incredibly profound, almost philosophical realization she had in a very ordinary place.

Mark: I’m intrigued. Don't leave me hanging. Michelle: She was on a bus, on her daily commute to work. And her mind was a million miles away. She was a professor, and she was mentally rehearsing this difficult conversation she needed to have with a student who was falling behind. She was running through different scripts in her head, trying to find the kindest, most effective way to say what she needed to say. Mark: I can definitely relate. I’ve had entire arguments in my head while staring blankly at a spreadsheet. Michelle: We all do it. But then, in the middle of this internal drama, she looks up and notices a woman sitting across from her. The woman has this soft, distant look on her face, and Prat, being a neuroscientist studying mind-wandering, immediately recognizes it. That woman was also a million miles away. Mark: Lost in her own world. Michelle: Precisely. And in that instant, it hits Prat with the force of a revelation. She's on this bus, physically sharing a space with dozens of other people. But mentally? She’s in a professor’s office, having a tense conversation. The woman across from her could be reliving a first kiss, or planning a vacation, or grieving a loss. Every single person on that bus was the star of their own, completely separate movie. Mark: Wow. So we're all just sitting in our own little private movie theaters, and the movie is being projected inside our skulls. Michelle: That’s exactly the metaphor. Prat says we think we’re just watching the movie of our life, but we’re not. Her central quote is, "You are neither an actor in nor the passive observer of your reality. You are the creator of it." Your brain is the director, the scriptwriter, the special effects team, and the audience, all at once. Mark: Okay, but hold on. I get the internal monologue part. But surely we're experiencing the same bus, right? The seat is real, the window is real. Where does objective reality end and the brain's story begin? Michelle: That is the million-dollar question, and it’s what makes her work so fascinating. The physical world provides the raw data—the light, the sounds, the sensations. But how that data is interpreted, what gets focused on, what gets ignored, what it means… that is 100% up to the individual brain. Michelle: Think about that famous internet phenomenon, "The Dress." Mark: Oh man, the blue-and-black versus white-and-gold war of 2015. It tore families apart! Michelle: It did! But it was a perfect, large-scale demonstration of this principle. The raw data—the pixels on the screen—was identical for everyone. Yet, millions of brains interpreted that exact same data in two completely different ways. Your brain made an unconscious call about the lighting in the photo, and that decision completely changed the reality of the colors you saw. Mark: So my brain is basically running Photoshop filters on reality without even asking me? Michelle: Constantly. And the filters it uses are unique to you. Which brings us to the next logical question: why are our internal movies so different? What makes one brain see blue and black, and another see white and gold? Mark: Yeah, what’s in the director’s toolkit? What makes my movie a quirky indie comedy while someone else’s is a serious historical drama? Michelle: That's the perfect question, because the reason our internal movies are so different comes down to the unique blueprint of our brains. Prat argues that our brains are not just designed differently from birth, but they are physically changed by what we do.

Mark: Okay, so this is where we get into the hardware. I always assumed my brain was pretty much the same as anyone else's, just with different software loaded on it. Michelle: That’s a common way to think about it, but Prat shows us the hardware itself is custom-built and constantly being renovated. She talks about the "mixology" of our brain chemistry, the balance of chemicals like dopamine and serotonin. She talks about brain asymmetry—how the two hemispheres of our brain are specialized for different tasks, and the balance is different for everyone. But the most powerful illustration of this is the concept of neuroplasticity. Mark: The idea that the brain can change itself. I’ve heard the term, but it always feels a bit abstract. Michelle: Well, let me make it concrete for you with one of the most famous studies in modern neuroscience, which Prat discusses. It’s about London taxi drivers. Mark: The ones in the classic black cabs? What about them? Michelle: To get a license to drive a black cab in London, you have to pass an insanely difficult test called "The Knowledge." It involves memorizing, without any notes or GPS, the entire layout of London. We’re talking 25,000 streets, thousands of landmarks, and the most efficient routes between any two points. It can take years to master. Mark: That sounds like an impossible task. My brain hurts just thinking about it. Michelle: It’s a monumental feat of spatial memory. So a team of neuroscientists, led by Eleanor Maguire, had a brilliant question: does forcing your brain to build this massive mental map of London physically change it? They used MRI scanners to look at the brains of these taxi drivers and compared them to a control group—in this case, London bus drivers, who follow fixed routes and don't need the same kind of mental map. Mark: And? What did they find? Michelle: They found a stunning difference. The taxi drivers had a significantly larger posterior hippocampus. The hippocampus is a part of the brain that’s crucial for spatial memory and navigation. Mark: So their brains literally grew a bigger, more detailed GPS module because they used it so much? That's incredible. Michelle: Exactly. And here's the kicker: the longer they had been a taxi driver, the larger that part of their hippocampus was. It wasn't that people with big hippocampi became taxi drivers; it was that the act of becoming a taxi driver grew that part of their brain. Their experience was physically sculpting their neural hardware. Mark: That’s wild. It’s like going to the gym, but for a very specific part of your brain. You do the reps—driving the streets—and that brain muscle gets bigger. Michelle: It’s a perfect analogy. And it’s not just about size. Prat tells another story from her own childhood that shows how even a single, dramatic experience can rewire us. When she was two and a half, she decided to ride her tricycle down a flight of stairs. Mark: Oh no. I can see where this is going. Michelle: It ended exactly as you'd expect: with a crash into the wall and a brief loss of consciousness. She calls it her first "Oh Shit" moment. But her brain didn't just register pain. It recorded that event as a profound, high-stakes learning experience. That one event created a powerful neural pathway about risk, consequences, and the physics of tricycles on stairs. Mark: A lesson you don't forget. So it’s not just long-term training like the taxi drivers, but also those big, emotional moments that leave a mark on our brain's blueprint. Michelle: Yes. Every lived experience, big or small, physically changes your brain. The language you speak, the hobbies you pursue, the people you love, the traumas you endure—they all leave their signature on your neural architecture. This is why no two brains are alike. Even identical twins with the same DNA will have different brains because they have had different experiences.

Mark: Okay, my mind is officially blown. So, let me see if I've got this straight. We start with the idea that we're all living in our own subjective reality, a movie created by our brain. And the reason those movies are so different is because the directors—our brains—are all unique. They have a different starting blueprint, and they are constantly being renovated by our life experiences. Michelle: You've nailed it. That's the whole arc of the book in a nutshell. Mark: So what's the big takeaway here? If my brain is unique and it's constantly changing, what am I supposed to do with that information? It feels a little overwhelming. Michelle: I think Prat’s message is ultimately one of profound empowerment and empathy. It’s a two-part takeaway. The first part is about self-compassion. Understanding your brain's unique design—your strengths, your quirks, the things you're naturally good at, the things you struggle with—allows you to stop fighting against your nature and start working with it. If you're not a 'normal' brain, and nobody is, then the pressure to be normal vanishes. Mark: That’s a relief. It’s permission to be yourself, but backed by neuroscience. Michelle: Exactly. And the second part, which is maybe even more important, is about empathy. Once you truly accept that every single person you meet is operating with a completely different brain, experiencing a completely different reality, it changes how you see them. The person who cut you off in traffic, the colleague who communicates in a way that drives you crazy, the partner who sees the world so differently—they aren't being difficult on purpose. Their brain is just running a different movie. Mark: It makes it harder to judge them. You don't know what's playing on their screen. Michelle: You don't. And that's the ultimate power of this idea. As Prat says, "You are the creator of it." And so is everyone else. Recognizing that shared creativity, even in its infinite diversity, is a powerful foundation for connection. Mark: It really makes you wonder... what story is my brain telling me right now? And what story is the person next to me living in? Michelle: A great question to carry with you. We'd love to hear what you think. What's one unique 'quirk' of your brain you've come to appreciate? Let us know on our socials. It’s a conversation worth having. Mark: This is Aibrary, signing off.