You have definitely had dreams that were ripped straight from your real life. You probably had one in the past week. Some of them replayed events from that very day. Relationship anxiety and job stress often play out nightly when you are in the thick of turmoil. Sometimes dreams mirror waking events exactly. Other times, there is a slight twist. Other nights, the imagery is pure symbolism.
There are no constants. Dreams are highly personal. They vary from person to person. This makes them difficult to study or quantify with certainty. It is also tough because we know so little about how the brain operates. Whether it is dreaming or solving a math problem, the mechanics remain murky.
Here is what we do know. Dreams definitely play out events from our waking lives. To understand how this happens, we need to look at how the brain processes memories. We all know about long- and short-term memory. But subdivisions under those umbrellas reveal more about how the machine works.
Declarative vs. Episodic Memory
Under the long-term heading, we have episodic and declarative memory. Declarative deals with things you can state. Think of it as knowledge you can declare. The sky is blue. Two plus two is four. Your favorite food is steak.
Episodic memories exist because of an experience you had. You are afraid of seagulls because one bit your finger at the beach when you were twelve. Both of these types are stored in the hippocampus. If you damage that area, you cannot form new declarative or episodic memories. This is why permanent amnesiacs often cannot remember their dog’s name or home address.
Because dreams are often culled from real life, some researchers believed the brain pulls from recently learned declarative memories. But amnesiacs seem to disprove that theory. If you cannot remember what you ate for lunch while awake, you shouldn’t be able to recall it in a dream, right? Not necessarily. Studies with amnesiacs suggest otherwise.
Implicit Memory and Dreams
A 2001 Harvard University study offers clues. Amnesiacs reported dreaming about things that happened the previous day. Trouble was, they did not recognize the dream reflected their own experiences. In the study, patients played the block-stacking video game Tetris for several hours daily. After sleeping, they reported seeing large blocks falling and rotating when falling asleep or in dreams.
They were amnesiacs. They had no waking memory of playing the game. They could not explain why they saw these blocks. Does this mean dreaming is a cure for amnesia? Not exactly. It suggests dreams do not draw from declarative memory. Instead, they draw from implicit memories.
Implicit memory is also known as non-declarative or unconscious memory. These are memories not part of waking consciousness. They are there nonetheless. Under this umbrella are procedural and semantic memories. Procedural memories include knowing how to ride a bicycle. You do not literally think “sit on the bike and put feet on pedals.” You just hop on and ride.
Semantic memories are more abstract. They live in the neocortex region of the brain. Participants in the study saw abstract semantic memories. They remembered blocks falling. They did not see themselves in a room sitting at a computer. We know amnesiacs retain implicit memories. After an injury, an amnesiac may not know their wife’s name. They still remember how to flush a toilet.
Why Dreams Feel Abstract
This leads to the theory that while we sleep, the brain files away millions of bits of information. Dreams may be what happens during this process. Work stress might play out clearly because the brain gives it more weight than the hot dog you ate for lunch. But you might dream about the hot dog. Or the hot dog might appear in your dream about work stress.
If the hippocampus is not responsible for dreams, and the answer lies in the neocortex and implicit memories, then abstract dreams make sense. We are left with no final answer on how the brain transforms reality into dreams. It is likely tied to memory processing. As more studies of the brain, sleep, and dreams are performed, our understanding may become clearer. For now, the mystery remains.
