On a rainy afternoon in Dublin in 2017, I was running late to see a movie. I was going to see Logan, the final chapter in Marvel’s Wolverine saga, and I arrived at the theater just as the movie was about to begin. It had been billed as a story about a reluctant hero who had nothing left to believe in. Vanity Fair had called it a “bracing, violent jolt … raw, true.” What would it look like if everything were stripped away and all you were left with was the pain of your present? I was intrigued. I sprinted to the electronic kiosk to grab a last-minute ticket. I snagged one of the few seats left, next to the aisle, and dashed toward the theater. Inside, 150 people sat in darkness watching a Star Wars trailer. My seat was on the far aisle. I didn’t want to climb over anyone, so I figured I’d run underneath the screen at the front and head up the stairs on the other side of the theater. Quick. Invisible. Easy. I adjusted my baseball cap, crouched to keep my head low, and sprinted under the screen. But there was no other aisle. Just a concrete wall, and I ran straight into it. The collision knocked me onto my arse. To make matters worse, the Smurfs trailer had exploded onto the screen at my moment of impact. A bright-blue mushroom house appeared, spotlighting me for the audience. The room erupted with waves of laughter. I picked up my displaced cap and straightened it, as if it mattered. Groggy and with my ego bruised (and possibly actually bruised), I traipsed back to the doors from which I had entered. I still had to make it to my seat. But now I had an audience. Your brain on black I like to think of myself as a relatively intelligent person. How could I have run straight into a large concrete wall? The answer lies in neuroscience. Most of us assume that our senses collect data, send it to the brain, and then we react. But a large body of research suggests that’s not how it works. Your brain is a gambling addict that bets on reality. It doesn’t wait for information. It guesses what should happen and adjusts when surprised. Most bets win. But when they don’t, you run into walls. You start with a prediction, a top-down expectation of what your brain thinks it’s about to see. Then bottom-up incoming sensory data either confirms this prediction or updates it if things don’t fit. This is known as the predictive processing theory. In 1999, Rajesh Rao and Dana Ballard built a computer model that worked the same way as the brain. They found that the higher-order areas of the brain were first making predictions about what they expected to see, and then sending them down the hierarchy. Only when something didn’t match the prediction — what they called a “prediction error” — did the lower levels sound the alarm and send information back up the hierarchy. When the brain guesses correctly, there’s no need to notice anything. When it guesses wrong, like mistaking a wall for an aisle, the system lights up. It’s not that I didn’t see the wall with my eyes. It’s that my brain never expected it to be there in the first place. This happens all the time with people when trying to solve problems, having conversations, and making decisions. The inner propagandist — the inner double agent — runs the show. The truth is whatever prediction doesn’t get proven wrong. The brain deals with a world full of data and ambiguous messages. It makes the best possible predictions in moments of uncertainty. We don’t realize we’re making guesses, of course. The brain fills in the gaps using past experiences and context to figure out what should be there. Tahts wyh yuo cna uesndratnd tihs snetecne eevn thuogh teh wrods aer jbmlued pu. Oh, nda I klei yuro silme. I could write the whole book like that, and you’d be able to understand it. But it would be painful to read, and you’d likely wish me dead afterward. But the point remains: You don’t just see, then believe. You believe, then you see. Most of the time, it works great. But now and then, there’s a glitch. Have you ever waved at someone who wasn’t there? Maybe you were walking down the street, and you saw a friend. So you smiled. Maybe you even raised your hand. And then you realized … it wasn’t them. This is an example of what feels like a positive hallucination, a moment when your brain sees something that isn’t there because it expects it to be. When you add to the scene around you. The brain deals with a world full of data and ambiguous messages. It makes the best possible predictions in moments of uncertainty. There are also negative hallucinations, when you don’t see what is there. When your brain has removed things from in front of you. “Honey, where are the keys?” “On the table.” “They’re not on the table. Where are they?” “On the table.” “They are not on the table. Why won’t you just tell me where you put … oh, never mind, found them.” “Where were they?” “On the table.” Sound familiar? Our inner propagandists work 24/7, filling in blanks, removing things, and selling us the illusion that we are, in fact, seeing the world as it is. But we are, in fact, not. Perceptions are predictions. Beliefs are predictions too. So why do we believe in the first place? The simple answer is because it’s something we need to do. The Cravings of the Brain Propaganda promises you a better future. It promises that everything will be taken care of. “Trust the leader. We’ve got this under control.” And just like that, we exhale. Inner Propaganda plays the same trick. It works behind the scenes to settle the storm inside. It is driven by your deepest needs for safety and stability. Between 2010 and 2019, Jeremy Clifton’s team at the University of Pennsylvania mapped humanity’s deepest worldviews. Mining tweets, religious texts, novels, speeches, and philosophy for phrases like, “The world is …” they distilled 26 core primal world beliefs. Our inner propagandists work 24/7, filling in blanks, removing things, and selling us the illusion that we are, in fact, seeing the world as it is. At the top of the list sits one master belief: Is the world good or bad? This lens filters everything. Beneath it are multiple dimensions including safe versus dangerous and enticing versus dull. These generalizations help us simplify the world and provide a way of interpreting ambiguous information or experiences that we encounter. Leaders who see the world as good and safe tend to be trusted more and empower others. Those seeing danger or dullness lead through control and fear. As human beings evolved over thousands of years, beliefs became the drivers for our behavior. If you do X, then Y will happen. All human progress is based on this idea. Our brains are driven by one core mission: to keep us from dying. To do that, our brains evolved to prioritize survival above all else. They crave two core needs: safety and stability. Safety is about avoiding danger. Stability is about keeping things as simple as possible. The problem is that optimizing for these two needs can lead you into mental blindspots, poor decisions, and sometimes even concrete walls. Understanding this is the first key to empowering your brain to make better choices. This article Your brain doesn’t see reality — it tries to predict it is featured on Big Think.