How the Brain’s Predictions Work

For a long time, I believed that when I had a headache after a hard day at work, the reason was simply tiredness. The pattern was almost always the same. I would come home. The day would slowly come to an end, and somewhere in the background there would appear a compulsion to pay attention to my head. Very subtle, but enough for my head to move from the background into the centre of attention — and become a problem.

And then, almost automatically, the thought would appear: “Oh… a headache is starting.”

After that thought, the pain would indeed develop. Sometimes I would take a painkiller, sometimes I would wait for it to pass, but in my mind the mechanism was already obvious: a long day at work ends with a headache.

Only after some time did I begin to wonder about something else. Did the pain really begin in the body… or did a thought appear first, announcing that it was coming?

I began to look more carefully at that moment. At the first signal from the body.

At the moment when an interpretation appears in the mind: “this is already the beginning of pain.”

And slowly I began to change something very simple. Instead of waiting for the pain, I focused my attention on calm, regular breathing, as if I were sitting peacefully on the sofa and watching an interesting film. After coming home, I ate calmly, rested, and allowed my body to slow down after the whole day of work.

Only later did I understand that in such moments something like a self-fulfilling prophecy may be at work. If the brain treats the thought “pain is about to start” as very likely, it begins to look more carefully for bodily signals that confirm it. Subtle sensations that would normally fade into the background suddenly become clear.

At first, not much changed. Sometimes it ended the same way as before — with a painkiller. But after some time I noticed something interesting. The headaches began to appear less often.

Then even less often. Until eventually they almost disappeared.

I do not know exactly when I stopped treating that tension in my head as a sign that pain was coming. But that was when I began to suspect that something more interesting was happening here.

Maybe I am not only reacting to reality. Maybe in many situations I am reacting to what my brain predicts is about to happen.

The Brain Does Not Only React — It Predicts

When I began reading about how the brain works, I came across a very interesting idea. Perhaps the brain does not work in the way I had usually imagined. It is not only an organ that records reality — like a camera filming the world.

More and more research suggests something different. The brain is constantly trying to predict what is going to happen next.

It predicts what I will see, what I will hear, how another person will behave, and even what my body is about to feel.

Based on previous experience, it builds a working model of the world. Then it compares that prediction with what actually happens. If everything matches, I barely notice it. But when a difference appears, the brain registers it immediately. This is the moment when tension, surprise, or the need to understand what is happening begins to appear.

Three Questions That Began to Change the Way I Look at Things

When I began to look at everyday situations in this way, a few simple questions appeared.

The first was very basic: am I reacting to what happened… or to what I expected to happen?

The second question concerned the body. Before an emotion or a reaction appears, there is often a very subtle signal in the body. Tension. Pressure. A change in breathing.

And then I began to ask myself: is this only a signal from the body… or is my brain already trying to build a story from it?

And finally, the most important question appeared. If the brain is constantly trying to predict the world… can I learn to notice these predictions at the moment when they arise?

Not afterwards. While they are happening.

The Most Surprising Discovery

When I began to look back at many situations from my life, what struck me most was not the mistakes themselves.

Not the fact that I was wrong. That happens to everyone. What moved me more was something subtler: how often I was absolutely certain that I knew. In many situations I had ready-made ways of thinking and reacting. At the moment when I used them, they seemed obvious and reasonable to me. There was not even a brief pause in which I could ask myself: how do I actually know that this is true?

Looking back, something else strikes me even more. In relationships with people close to me, that certainty was often strongest. The closer someone was — family, friends — the more convinced I was that I knew what I was saying and why I was right.

I also began to suspect something else. Perhaps that certainty does not come from the fact that I truly see the other person better. Maybe it is the opposite. The better I know someone, the less I actually see them… and the more I predict who they are and what they will do.

And I began to wonder how many of my reactions were truly responses to the situation… and how many were only my brain’s prediction of what that situation should be.

A Starting Point for the Road Ahead

Over time, I began to understand something else. Perhaps, to a large extent, I live in the world of my brain’s predictions. And freedom begins when I start to see them.

Not in order to control every thought. But in order to see how my interpretations, emotions, and reactions arise. Because I realise that, in relation to myself, I am not responsible for every thought that appears in my mind. But I am responsible for what I do with those thoughts. After all, to a large extent, the result of this process is my life.

In this sense, I am not only a passive receiver of what happens in my body. The way I interpret signals from the body, and what I direct my attention toward, can strengthen certain sensations… or allow them to disappear quietly.

In the next texts, I will try to look at this more closely. First, at how the brain’s predictions work in the body and in everyday situations. Then, in relationships with other people. And finally, in something even deeper — in how predictions build my sense of who I am.

This text was originally written in Polish (“Jak działa przewidywanie mózgu”) and translated into English with AI assistance. The ideas, reflections, and personal experiences presented here remain my own.