Imagine that every night your brain shoots a movie. It writes the script itself, uses your acquaintances as actors, combines completely unconnected memories, and doesn’t care much about the laws of physics.
You might be in your childhood home, but meet someone there whom you had never even seen back then. Then you walk out of the room and find yourself in a completely different city. The person you’re talking to suddenly turns into someone else, and you don’t see anything unusual about it.
For me, this has always been the most bizarre aspect of dreams. Not that impossible things happen, but that at the moment, we almost never question this impossibility.
While we sleep, the absurd is reality. Why does the brain do this?
When Dreams Were Messages from the Gods
People tried to answer the question posed above thousands of years before the emergence of science.
In ancient Egypt, dreams were perceived as divine messages and signs of the future. An ancient Egyptian text, now called the “Dream Book,” has survived to this day. It describes various dreams and indicates what is a good or bad sign.
Dreams also held an important place in ancient Greece. In Homer’s texts—which have once again come into the wider spotlight in anticipation of Christopher Nolan’s The Odyssey—a dream could be a message sent to a human by the gods.
As time passed, attempts to explain dreams more naturally began to appear.
Aristotle linked dreams to human sensations and processes occurring in the body, and no longer considered divine intervention a necessary condition to explain them. This was a significant shift. The search for the cause of dreams moved from the supernatural world to humans themselves.
There’s one thing I particularly like about this history. The ancient Egyptian, the Greek from Homer’s era, and the person lying today in a sleep lab with EEG electrodes attached to them are separated by thousands of years. Yet, upon waking, all three might have the exact same question: What was that?
Only where we look for the answer has changed. Once, the explanation for dreams was sought in the gods; today, we trace it in the sleeping brain.
And yet, thousands of years later, we still don’t have a final answer to the main question. Why do we dream?
Instead of a single answer, I will try to explore a few interesting hypotheses.
Memories That Blend Together
Throughout the day, the brain takes in a massive amount of information. We see people, read, work, learn, feel joy, get irritated, and notice countless details that we won’t even be able to recall a few minutes later.
By falling asleep, the processing of this information doesn’t stop. Accordingly, sleep is crucial for memory. During this time, processes occur in the brain that help consolidate memories, process experiences, and connect new information with existing knowledge.
Perhaps this is why fragments of our real life often end up in our dreams. Except, the brain doesn’t replay memories like a video recording.
When observing my own dreams, I’ve often thought that their strangeness lies not in individual details, but in how these details are connected. The people and places are familiar, sometimes I even know exactly where an emotion comes from, but ultimately, it forms a story that never actually happened.
It’s as if the brain takes the material accumulated during the day, dismantles it into pieces, and reassembles it in a completely different sequence at night.
This might be why we encounter such a bizarre mix of the familiar and the entirely alien in dreams.
Why Does Nothing Surprise Us?
And here arises what is, for me, the most interesting question. Why do we believe all of this?!
In a dream, boundaries barely exist. You might suddenly find yourself in another city, a person might turn into someone else, or something completely impossible might happen, and yet everything seems perfectly normal to you.
We started flying? No problem! The room suddenly turned into a street? Let’s keep going, it’s a lovely street! The person we were talking to is now someone else? That’s not a particular issue either, talking to them is interesting too!
In a waking state, such things would immediately make us suspicious. But in a dream, we no longer check the logical sequence of events and reality with the same strictness.
During REM sleep, different systems in the brain work differently. Regions associated with emotions and memory can be quite active, while some areas involved in planning, self-control, and critical evaluation during wakefulness are in a different mode of activity.
As a result, we get a highly vivid experience in a world whose rules can change at any second.
This might partially explain why we accept the absurd events of a dream so easily. The brain creates an emotionally convincing world, but the systems that help us reality-test and detect contradictions while awake are no longer operating in the same mode.
In other words, the dream is real enough for us to believe it, while our inner skeptic isn’t fully awake.
Emotions Follow Us Into Sleep
If you were deeply anxious about something during the day, that feeling can carry over into your dream.
The interesting part is that the dream doesn’t necessarily have to replicate the real event. You might have had a tough day at work, but in your dream, you’re running late for an exam. The events are different, but the emotional backdrop remains the same. Anxiety, tension, embarrassment, or the feeling of losing control can manifest in a completely new scenario.
That’s why scientists are studying the possibility that dreams are also connected to the processing of emotional experiences. On the other hand, this doesn’t mean we should definitely look for hidden messages in every dream.
The Dream as a Simulator
There is another, particularly interesting idea, and I must admit, it’s my favorite!
Have you ever been chased in a dream? Lost your way? Been late for an important meeting? Or found yourself in a situation with no way out?
According to one hypothesis, a dream might be a kind of simulator. The so-called threat simulation hypothesis suggests that the brain plays out threatening situations in a safe environment. It’s as if it’s rehearsing for real life.
Broader versions of this idea also include social situations. In modern life, a threat isn’t always escaping a predator. Conflict, rejection, embarrassment, missing an important meeting, or being judged by others can also be powerful emotional experiences.
It is possible that the sleeping brain models similar scenarios as well.
The idea is certainly appealing. We lie safely in bed while the brain throws us into all sorts of disasters so we can practice dealing with them.
We Don’t Just Dream During REM Sleep
You might have heard that we most often associate dreams with REM sleep, a phase whose most obvious sign is rapid eye movement.
There is a reason for this. During REM, dreams are, on average, longer, more vivid, more emotional, and more bizarre.
On the other hand, despite popular belief, dreams don’t only occur during REM.
In a laboratory setting, when people are woken up during different sleep phases and immediately asked what was happening in their minds, they describe dream-like or other sleep-related experiences from other phases as well.
Therefore, it’s highly possible that a person who says “I don’t dream at all” is simply failing to remember their dreams.
Where Do Dreams Go After Waking Up?
Many of you have probably experienced this. You wake up, and for a few seconds, you remember the entire dream. You know where you were, who was with you, and what was happening.
Then some part of it fades… In another few minutes, you might only be left with a single scene. And a bit later, sometimes all you remember is that you dreamed about something.
This is another characteristic of dreams that I’ve hated since childhood. Sometimes, right upon waking, I try to recall the dream from beginning to end, and I can almost feel it slipping away.
You’ll probably agree, it’s definitely not a good feeling… It’s as if a few minutes ago you were truly somewhere, and now that place is drifting away from you forever. First, the conversations disappear, then the people, and finally, only a single frame or emotion remains.
Dream recall is also influenced by when and how we wake up. If we wake up during a dream or shortly after, the chances of remembering it are higher.
So let’s agree: “I don’t remember” and “I didn’t dream” are not the same thing.
And Yet, Why Do We Need Dreams?
Thousands of years ago, a person might have had a quite “precise” answer to this question. A dream heralded something, warned of something, or hinted at the future.
Today, we know much more about the brain, and paradoxically, the answer has become more complicated.
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Perhaps dreams are linked to memory;
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Perhaps they participate in emotional processing;
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Perhaps they serve to simulate various situations;
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Or maybe dreams don’t have one specific function at all, and are simply the byproduct of the processes already happening in the sleeping brain.
Personally, this very uncertainty is what I like most. Dreaming is such a universal experience that almost everyone can talk about it. At the same time, science still cannot tell us exactly why it exists.
Let us remember: every night, when we temporarily disconnect from the outside world, the brain continues to work. It creates spaces, people, and stories. It mixes memories, emotions, and completely imagined events. And for a few minutes, we might perceive all of this as just as real as the world we return to after waking up.
In the morning, this world disappears, and often only a few frames remain of it.
This is how countless brilliant stories and scenes are lost. Who knows how many magnificent scripts our brain has directed, which we forgot forever just minutes after waking up.
Perhaps, inside each of us lives a screenwriter and director who doesn’t even remember most of their own best work.
