Why do we dream?

When we fall asleep, it can feel as though we are entering an entirely different world.

The strangest things happen there.

Suddenly, your whole room is full of monkeys. Or perhaps a large bear is chasing you, but no matter how hard you try, your legs cannot run fast enough.

Everything can feel incredibly real.

Until you wake up and realise it was just a dream. 

But why do our brains create these move-like experiences while we sleep? 

Very mysterious and strange 

To understand a little more, we spoke with Professor Johan Frederik Storm. He studies the brain.

"People have wondered about this for centuries," he says.

Storm is an expert on the brain, sleep, and wakefulness.

"No one knows for certain why we dream. The fact that we dream is both mysterious and strange," says the professor.

Even so, he has some ideas about what happens when we close our eyes for the night. 

The brain creates experiences of its own

Perhaps unsurprisingly, it all happens in the brain.

When we are awake, we experience the world through our senses. Everything we smell, taste, see, hear, and touch sends information to our brain, which processes all this information.

When we are in deep sleep, sensory input from the outside world is reduced, but the brain doesn't completely switch off.

“What we believe is that the brain creates experiences on its own, and at that moment, they seem just as if they were real,” says Storm.  

But why does the brain do this every single night? And is it useful to us in any way?

To survive? 

One possible explanation is that dreams help us survive and that this is why we have developed the ability to dream.

After all, there are certain situations that our brains could benefit from practising in advance so that we can handle them well.

“For instance, we might dream about escaping from a dangerous predator,” says Storm. 

But human survival also involves being well liked by others. 

“It's also common to dream about an embarrassing situation in which we say or do something foolish,” says the professor.

Dreams may therefore allow us to rehearse difficult, uncomfortable, or dangerous experiences while remaining completely safe in our beds.

To learn better? 

Another theory is that dreaming improves our ability to learn.

“Our dreams often contain elements that resemble things we have experiences in real life. But at the same time, they're often more jumbled and don't quite match the real world around us,” says Storm. 

According to this theory, the brain mixes together old memories to create new situations that we have never encountered before.

"This is to help us learn better. The brain creates new examples based on the old examples we have encountered, so that we develop a more complete understanding of what might be possible," Storm explains. 

According to the professor, this makes it easier for us to understand new situations. 

"It might also make us more create, allowing us to imagine possibilities we have never considered before," he says. 

In other words, dreams could help prepare us for new experiences, deepen our understanding of the world, and strengthen our ability to learn.

To learn less? 

An older and somewhat less popular theory is that we dream in order to forget.

According to this explanation, we take in so much information while we are awake that we need to get rid of the useless information while we sleep. The brain's response is to dream. 

"This is important for creating balance in the brain's network," says Storm.

To illustrate the idea, the professor describes what might happen if the brain did not properly process information during dream sleep.

"Imagine seeing a snake in the forest just once. Without this process, your brain might begin interpreting every stick or twig you encounter as a snake," he explains.

However, he is not entirely convinced that this theory is correct because the explanation assumes that the content of dreams is so disconnected that it makes no sense to us. 

"Dreams can be coherent stories. They are often absurd and strange, but they are not necessarily pure chaos," he says. 

We still don't know for sure

These three theories offer different possible explanations for why we dream. But experts do not know for certain which one is correct. 

Professor Storm believes that the first two explanations, concerning survival and learning, could both be true.

"It's not necessarily the case that one of the theories has to be wrong," he says.

And perhaps the real explanation is something entirely different, something researchers have not even considered yet.

———

Translated by Alette Bjordal Gjellesvik

Read the Norwegian version of this article on ung.forskning.no

Source:

Dream (sleep phenomenon), Britannica.

Related content

Why do we become overtired?

How can it be normal to sleep anywhere from six to ten hours?

Subscribe to our newsletter

The latest news from Science Norway, sent twice a week and completely free.

Sign up