By Anju Miura

I was gripping a shotgun, while being chased by a grizzly bear, running in the dark woods. After screaming, waking myself up and falling out of a bed, I realized it was a dream. I wondered, if we sleep to relax our bodies, why do we dream and why do we have nightmares that scare and awake us?

Humans have been fascinated by the mystery of dreams since the dawn of time as Mesopotamian kings recorded and interpreted their dreams. In spite of all of the scientific research following technological advancement and persistence, we still don’t have definite answers to why we dream.

However, scientists developed some intriguing theories to understand why we dream. We dream to fight our anxiety, to fulfill our wishes, to memorize and to forget.


Anxiety Dreams

Sleep is not simply a break time that our brain and body go dormant. Sleep is another state of consciousness. According to the threat simulation theory, we dream to rehearse.

Dangerous and threatening dreams are very common, and many of us often realize our anxiety through our nightmares. An anxiety-filled night of escaping from a shark in a swimming pool or running into a classroom five minutes before the exam allows us to practice our fight or flight instincts.

Our nightmares prepare us and keep our instincts sharp in case we will face these situations in real life.


Wish Fulfillment

Sigmund Freud said that we dream to fulfill our wishes. He suggested that all of our dreams including our nightmares are a collection of images from our daily conscious life events.

For example, if you have a dream of eating ramen noodles in your statistics class because you had a class on that day and craved ramen before you went to bed. Objects in our dreams have symbolic meanings that relate to the fulfillment of our subconscious wishes.

Everything we remember from our dreams is a symbolic representation of our unconscious urges and desires. A snake may indicate your sexual desire, a spider may represent your fear and a wallet may symbolize your status.

Freud also believed, by analyzing those remembered elements of our dreams, the unconscious content would be revealed to our consciousness, and psychological issues stemming from repressed unconscious feelings could be addressed and resolved.



Sleep is necessary to increase our performance on certain mental tasks, and dreaming helps us improve our memory.

A 2010 study indicated that certain memory processes can happen only when we are asleep, and dreams are a signal that this memorization is taking place. Research participants were better at getting through a complex maze if they have napped and dreamed of the maze prior to their second attempt as compared to those who didn’t take a nap and those who napped but didn’t dreamed about the maze.

Spending a night cramming before the exam, you may fall asleep and have a nightmare studying forever. However, that nightmare is actually helpful for you to memorize what you were studying.


Reverse Learning

We also dream to forget. Forgetting is one of the most complex human capabilities. Unlike computers that store billions of information and eventually reach their limits, human brains automatically interpret what we need to remember or not and store information accordingly.

A theory of dreaming suggests that while sleeping, mainly during the Rapid Eye Movement sleep cycles, human brain reviews its neural connections created by our thoughts and actions and eliminates unnecessary information.

Without this “unlearning” process which happens while we dream, our brain can be overrun by useless connections and parasitic thoughts could disrupt our necessary thought process we have to do while we are awake.