Your Brain is a Prediction Machine
- Janet Nash, MSW, LISW-S
- 1 day ago
- 8 min read
Why thoughts feel true even when they aren't
I often tell clients that the brain is like an enormous computer drive containing billions of files. Now, I know the brain does not actually contain neat little folders labeled Fell on Ice, 2019 or Awkward Conversation, 2012, but as a metaphor, it works pretty well. Our brains hold on to past experience, and they use what has happened before to help predict what might happen next.
This is enormously useful. If I once slipped on an icy sidewalk and landed hard enough to remember it vividly, my brain is going to be considerably more interested in icy sidewalks from that point forward. Before I fell, I might have looked outside, noticed the ice, put on my boots, and gone about my day. After the fall, there is another file available: ice, falling, pain, be careful.
So the next time the roads are slick, I may decide to stay home. That may be perfectly reasonable. But what if the sidewalks have been salted, the roads treated, I have good boots, I am mobile, and the conditions are actually quite manageable? My brain may still be pulling up the old file and predicting that if I go outside, I could fall again. Possible? Yes. Inevitable? No.
And therein lies the problem. We are relying on the faulty premise that because there is ice, we will fall, rather than acknowledging the more accurate possibility that we may fall.
Our brains are predicting all the time. They are analyzing, comparing, evaluating, judging, anticipating, and attempting to make meaning out of whatever is happening in front of us. Much of this occurs automatically, before we have consciously decided anything at all.
Our brains are basically running a private little Kalshi prediction market all day long, making bets about what is going to happen next. Anxiety, unfortunately, is a very overconfident prediction machine. I’ve tried giving Anxiety the number for Gamblers Anonymous, but apparently it doesn’t think it has a problem.
Then the brain presents us with its conclusion in the form of a thought, and we believe it to be true simply because we thought it. If I thought it, it must be true!
Thoughts Are Just Thoughts
One of the things I say most often in therapy is that thoughts are thoughts. They are not facts. This sounds ridiculously simple until you notice how rarely we behave as though it is true.
A thought appears: She's angry with me. Something bad is going to happen. I'm going to embarrass myself. I can't handle this. This relationship isn't going to work. Everyone else knows what they're doing except me. Almost instantly, we begin responding to the thought as though somebody has handed us notarized documented evidence.
But thoughts vary enormously in quality. Some are thoughtful, reasonable, useful, and informed by current circumstances. Others are, frankly, not worth the neurons it took to fire them! This is not because we are defective thinkers. Our thoughts are shaped by everything that came before them: experience, temperament, relationships, culture, grief, anxiety, depression, trauma, fear, and whatever happened yesterday afternoon.
If I am anxious, my brain is much more likely to overestimate danger and underestimate my ability to cope. If I am depressed, I may look at the future through a lens that makes possibility appear considerably narrower than it actually is. If I have experienced trauma, my nervous system may interpret something familiar as dangerous long before I have had time to determine whether danger is actually present.
It is a little like putting on anxiety-shaded glasses. Everything I see is filtered through them. The world has not necessarily changed, but the tint has. And because I am looking through the glasses, the view feels entirely real.
The Snake That Wasn't There
Years ago, during my yoga philosophy training, I became fascinated by the idea of superimposition.
Adi Shankara, an eighth-century Indian philosopher and one of the great teachers of Advaita Vedanta, used a wonderfully simple story to explain superimposition. The story is about a person entering a darkened room and seeing what appears to be a snake coiled in the corner. The body responds immediately with fear. The heart races, the muscles tighten, and the person may freeze or back away. Then someone turns on the light.
It is not a snake at all. It is a coil of rope.
The snake was never there, but the fear was real, and the body reacted to what it thought it saw.
I remember learning this and immediately thinking about trauma. Superimposition describes the way we can place something from our own perception, history, or expectation onto what is actually in front of us. In the dim light, the rope takes on the qualities of the snake.
We do this psychologically all the time. Something happening now resembles something painful that happened before, and our big old brain says, I know this. I have a file on this. Then it fills in the rest.
The tone of someone's voice resembles the tone an angry parent once used. A partner becomes quiet, and suddenly the silence feels like abandonment. A supervisor asks to speak with us, and before the meeting has even happened, we have mentally lost our job, disappointed everyone we know, and begun investigating whether we can live comfortably on Social Security.
The rope becomes the snake.
Trauma Has a Very Long Memory
Trauma makes this process particularly powerful because traumatic memory does not always behave like an ordinary autobiographical memory. We may intellectually know that something happened years ago, yet a smell, sound, expression, place, sensation, or interpersonal dynamic can activate the nervous system as though the old event is occurring now.
The body reacts before the thinking mind has caught up. This is why someone can say, I know I'm safe, and still feel terrified. The knowing and the feeling are not necessarily happening in the same part of the system at the same speed.
Peter Levine, PhD, psychologist and developer of Somatic Experiencing, whose work on trauma has influenced me enormously, has long been interested in what happens in animals after a life-threatening event. He has described animals in the wild escaping a predator and then trembling, shaking, or otherwise discharging some of the intense activation associated with survival. Then, assuming the danger has passed, they return to grazing, moving, resting, or whatever it is antelope do after narrowly avoiding becoming a lion's lunch.
Humans are considerably more complicated. We have these enormous frontal cortices capable of remembering, imagining, analyzing, planning, regretting, anticipating, replaying, and occasionally conducting a complete retrospective investigation of every questionable decision we have ever made at three o'clock in the morning. Our capacity for reflection is extraordinary. It can also be exhausting.
We can survive the lion and then mentally reconstruct the lion for decades.
The Brain Is Trying to Help
I think this part is important. The brain is not deliberately trying to make us miserable. It is trying to protect us.
If something hurt us before, remembering it makes sense. If someone betrayed us, becoming more cautious in relationships makes sense. If we were humiliated publicly, becoming apprehensive about speaking in front of people makes sense. If we were raised by an unpredictable parent, becoming skilled at reading tiny changes in someone's expression may have been extraordinarily useful.
The brain's job is not primarily to make us happy. Its job is to help us survive, so it uses what it knows. The problem comes when old information is treated as if it is the only information.
I slipped on ice once. That is true. The sidewalk is icy today. Also true. Therefore, if I leave the house today, I will fall. That is a prediction. It is not a fact.
There may be other information my brain has not incorporated yet. The sidewalk has been salted. I am wearing good boots. I can walk slowly. The temperature has risen. Someone can come with me. The present moment contains information that the old file does not.
What Is Actually Happening Now?
This is one of the reasons mindfulness became so important to me, both personally and clinically. Mindfulness does not ask us to stop thinking. Good luck with that. Nor does it ask us to replace every uncomfortable thought with a cheerful one.
It asks us to notice what the mind is doing. There is the prediction. There is the old memory. There is anxiety telling me what it thinks will happen.
Then we return to the present moment and ask: What is actually happening now?
Not what happened ten years ago. Not what happened in another relationship. Not what I fear might happen tomorrow. What is here? Just the facts, ma'am, only the facts!
Sometimes, of course, what is here really is dangerous or painful. Mindfulness is not denial. If there is actually a snake in the corner, I strongly recommend responding accordingly.
But sometimes there is a rope.
The challenge is giving ourselves enough light to tell the difference.
Updating the File
The brain changes through experience, and this is one of the most hopeful things about it.
If I repeatedly encounter icy sidewalks safely, my brain acquires new information. If I speak in a group and survive the experience, there is a new file. If I set a boundary and the relationship remains intact, there is another. If I disagree with someone and they do not abandon me, another. If I ask for help and am met with kindness instead of ridicule, another.
The original experience does not disappear. I do not need to erase the old file. I need more files.
New experiences teach the nervous system that the old prediction is not the only possible outcome. Even our private little Kalshi prediction market has to revise the odds eventually. This is part of what healing looks like: not convincing ourselves that nothing bad will ever happen again, because that would be another rather questionable prediction, but becoming more flexible.
This happened before. It may happen again. And it may not.
That tiny opening creates choice.
Turning on the Light
I still avoid icy sidewalks when I can. I have no particular interest in proving psychological growth by falling down again. But I also try to notice when caution has quietly turned into certainty. That is the point at which I want to take another look.
What am I predicting? What past experience is my brain using? What is anxiety adding to the picture? What information is available now that was not available then? Is there actually a snake in the corner, or am I looking at a rope in bad lighting?
Our big old brains are marvelous things. They remember, protect, anticipate, create meaning, and occasionally make mistakes. A thought can feel absolutely true and still be a prediction, an interpretation, or an old memory superimposed upon the present.
Sometimes the work is not to argue with the thought.
Sometimes we simply need to turn on the light and look again.
A Reflection
The next time you notice yourself becoming anxious about something that has not actually happened yet, pause for a moment and ask yourself what your brain is predicting and what old file it may be pulling forward. Then, perhaps most importantly, ask: What is actually true right now?
You may still decide not to go out on the ice. But at least you will know whether you are responding to today's sidewalk or yesterday's fall.
