By: Alisha Gomes
We all know that feeling: you wake up after a restful night's sleep and only remember fragments of a dream. If an image of Ryan Gosling constantly pops into your head throughout the day or a heinous monster gobbling up the city makes you spill your cereal, your brain is reminding you of a dream you had the night before.
Why do we remember these dreams? And why don’t we other times? In truth, we only know dreams from memory after we are awake.
Throughout the day, dreams do not piece together—instead, they become more fragmented as we fill our working memory with other information. To truly understand why we remember dreams and why we don’t, we must first understand the concept of memory.
Memory is an interesting topic not just for neuroscientists but for the public alike. There are three main categories within memory itself: working memory, short term memory, and long term memory.
Working memory, a theoretical concept in cognitive psychology, is a system with finite volume responsible for temporarily holding information to get processed.
Working memory is often confused with short term memory but these two concepts are not interchangeable. Short term memory, in contrast to working memory, is a system that simply holds information, which does not require processing. Short-term memory is the process that creates patterns of activated neurons which can be combined, sequenced, and manipulated. (Think of Dory from Finding Nemo. She had an excellent capability of remembering things that happened many years ago but not things that happened seconds ago).
Long term memory, in contrast to both working memory and short term memory, holds information indefinitely. Long term memory is the process that creates a structural change in brain circuitry. Tasks like tying your shoes, riding a bike, brushing your teeth are all skills that do not involve conscious thought and therefore are a result of your long term memory of these tasks. When it comes to dreaming, short term memory must be active, while long term memory must be inactive.
All the reasons for forgetting dreams are the same reasons that you forget things while you are awake. While awake we forget constantly. Why did I walk into this room? Where are my car keys? What time do I pick up my daughter from daycare? We usually forget information because our brain necessitates stronger images for things to be remembered. Dream images are usually forgotten because the brain does not see the information as being peculiar or necessitating long-term memory. Stated simply, your brain considers these dream images as irrelevant. This is why you can easily remember the most peculiar dreams that you have and not your most “normal” dreams.
Sigmund Freud, the founder of psychoanalysis, was infatuated with the idea of dreams and particularly about forgetting them. In his book called The Interpretation of Dreams, he says “After waking... .the world of the senses presses forward and at once takes possession of the attention with a force which very few dream-images can resist; so that here too we have another factor tending in the same direction.”
Research is still being done on the mechanisms that underlie dreaming and the close relationship our dreams have with our memories. Though we have a greater idea of what dreams are since Freud’s time, dreaming is still considered a great scientific mystery today.
What Did You Learn?
1. Q: What are the different types of memory?
A: There is long term memory, short term memory, and working memory. Long term memory is for the long term storage of information whereas short term memory holds information that is in a readily available state for a short period. Working memory, in contrast to both long term and short term memory, is for the temporary storage of information that may be manipulated.
2. Q: Why do we remember some dreams but forget others?
A: Dream images are usually forgotten because the brain does not see the information as necessitating long-term memory. Also, throughout the day your brain becomes overwhelmed with other stimuli that require the use of your memory. As a result, throughout the day you begin to forget about the dream you had the night before.