The Relationship Between Dreams And Memories

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woman dreaming

Your heart is pounding, and sweat is dripping down your face as you run up a hill that suddenly turns into an escalator — moving in reverse. In the next instance, you’re catapulted to your 10th birthday just as you blow out the candles. In a waking state, this is an impossible situation, but under the cover of night, where dreams and memories often clash, anything is possible. What does it mean exactly? We can’t say for sure, but you might need to work some things out. 

Rest assured, though, you’re not alone. Everyone dreams. And while this phenomenon is a prolific part of the human condition, it remains cloaked in mystery. The purpose of dreams has been a subject of speculation for thousands of years. And what little we know is likely just a drop of water in an ocean of possibilities. 

Do Dreams Serve A Purpose?

While there’s no clear consensus on the purpose of dreaming, theories abound. “The psychology of dreams and sleep is a topic that has been debated for centuries,” says Dr. Katherine Hall, a sleep psychologist at Somnus Therapy. She points out that Carl Jung, the founder of analytical psychology, was one of the first to suggest that dreams might serve an important function. 

“According to Jung’s theory of dream analysis, called the ‘symbolic method,’ all dreams contain hidden meanings and symbols that indicate deeper psychological processes taking place within our unconscious minds,” she says. 

Other theories on the purpose of dreams include the possibilities that dreams help us with problem-solving, memory consolidation, and emotional regulation.

Activation Synthesis Theory

First developed by J. Allan Hobson, The Activation Synthesis Theory of Dreaming suggests that dreams don’t mean anything. They’re really just a result of electrical brain impulses pulled from random thoughts and imagery from our memories. Stories that come from dreams are a result of humans waking up and attempting to fill in the blanks. 

The Threat Simulation Theory

The Threat Simulation Theory of dreams was brought to us by Finnish cognitive neuroscientist Antti Revonsuo. According to Revonsuo, dreams are akin to “an ancient biological defense mechanism” that’s deeply entwined with survival. In layman’s terms, dreams are a rehearsal of sorts that allows our brain to simulate fight-or-flight situations during sleep. 

Or, as the experts say, dreams allow us to rehearse “the cognitive mechanisms required for efficient threat perception and threat avoidance, leading to increased probability of reproductive success during human evolution.” Interestingly, the fact that dangerous situations, drowning, falling, being chased, and being late are common themes in dreams could lend some credence to the theory. 

The Contemporary Theory Of Dreaming

In his Contemporary Theory of Dreaming, Ernest Hartmann, professor of psychiatry at Tufts University School of Medicine, suggests that dreams are a way for us to process emotions. Moreover, Hartmann suggests that dreams are not random firings of neurons but instead shaped by the emotions of the dreamer. For example, if someone found themselves trapped in a fire and only rescued by firefighters at the last minute in real life, they might dream about being trapped by fire again — or being locked in a room, lost at sea, or stuck on a subway. All of these dreams play on the same fear: being trapped with no way out. 

The Expectation Fulfillment Theory

According to the expectation-fulfillment theory, dreams function as a release for emotions or feelings that the dreamer could not express in a waking state due to impropriety or safety reasons. 

If you’ve ever had a scenario play over in your head because you wish you could have reacted a different, perhaps more reactive, way — say, when dealing with an ex or working with a particularly cankerous colleague — you might find that ideal scenario creeping into your dreams. 

Overnight Therapy Theory 

According to neuroscientist, professor at the University of California at Berkeley, and author of Why We Sleep, Matthew Walker, dreaming is an “emotional convalescence” or overnight therapy, if you will. Not only does dreaming play a role in improving creativity, but it’s also associated with improved problem-solving and allows us to process painful events better. 

What Is The Difference Between Dreams And Memories?

A memory is a precise recollection of past events, and according to the Merriam-Webster Dictionary, a dream is “a series of thoughts, images, or emotions occurring during sleep.” From time to time, our dreams may include snippets from our memory bank, but the images and recollections may be confusing or dubious at best. So, while the lines may often blur between the two (which we’ll see later), dreams and memories are two distinct processes.  

The Relationship Between Dreams And Memories

While dreams may seem like a hodgepodge of images that flash through our mind’s eye with no rhyme or reason, there may be a method to the madness. 

For starters, “Dreams can also be a way for the brain to sort through information that it has taken in during the day,” says Tom Greenspan, sleep science coach and Co-Founder of Vs Mattress. “For example, if something traumatic has happened during the day, the brain may turn that experience into a dream in order to try to make sense of it (a process Sigmund Freud famously referred to as “day-residues.”) Additionally, dreams can help us remember things we have experienced and store them as memories.” 

 And in case you were wondering what science has to say about it, there’s plenty of research to support Greenspan’s point. One study conducted at Harvard Medical School beautifully illustrates the process. To assess the effect of sleep and dreaming on processing information and recall, researchers trained 99 participants to navigate a virtual maze for 45 minutes. Following the training, half of the group was allowed to nap while the other half studied and rehearsed the maze in a waking state. 

When both groups were tested on the maze later that day, researchers found that participants who dreamt about the task showed the most improvement. In fact, the group that slept (and dreamt) about the task performed six times better than the waking group.  

Can Memories Come From Dreams?

For some people, past dreams can subsequently feel like real memories — an experience commonly referred to as “dream-reality confusion.” If you’re scratching your head, wondering how the line between dreams and memories can become so blurred, consider this: Human memory is both fallible and malleable. So much so that dreams can easily distort what we believe to be the actual version of events. It’s more common than you might think and is well-documented.  

One study out of Maastricht University in the Netherlands showed that 12 percent of participants had some difficulty distinguishing dreaming and reality. In other words, their dreams led to false memories. In another study from the University of Quebec, researchers found that “between 3 percent and 7 percent of the dreams reported in long-term recall were probably naturally occurring false memories of dreams.” 

Ultimately, dreams and memories are different processes, but they share enough similarities that misattributions are common. 

Are Dreams Of Memories Normal?

“There is a lot of crossover between memories and dreams,” says Isabella Gordan, a Sleep Science coach and co-founder of Sleep Society. “Memories can oftentimes trigger dreams, and memories can also show up in our dreams. However, not all dreams are based on memories — some are simply the product of our subconscious minds working away while we sleep.” Gordon tells Sleepopolis that it’s normal for “dreams to contain snippets of our past, and it’s also normal for them to reflect our current worries or concerns.”

Research confirms as much. A 2021 study showed that as much as 53.5 percent of dreams were traced to a past memory, and nearly 50 percent were connected to multiple past experiences. 

“Our dreams are not precisely memories, but memories can sometimes inspire them,” says Hall. “In addition, some people experience dreams about memories or even future events. While this may seem strange at first, it is a relatively common occurrence and can be explained by how our brains process information. For example, research has shown that during sleep, our brain stores new information in long-term memory. And while we are dreaming, our brains continue to replay memories and events, often combining them with other memories or experiences to create something new.” 

Before we move on from the topic, it’s worth noting that the memories in most people’s dreams are often just tiny snippets of events, and whole episodes, or episodic memories in dreams, are actually quite rare. Beyond the influence of memory on our dreams, the images and snippets we experience are often tied to our waking life, interests, and lived experiences. For example, swimmers are more likely to dream about swimming, and chefs are more likely to dream about cooking and baking. 

Why Do I Remember Some Dreams Vividly And Have No Recollection Of Others? 

While dreaming is a universal experience, not everyone remembers them, and forgetting dreams is considered completely normal.

“Research shows that we are more likely to remember the dreams we had during REM (rapid eye movement) sleep, which is the final stage of the sleep cycle,” says Hall. During REM sleep, our brain is highly active, and the images in our dreams are more vivid than during other stages of sleep. And research confirms as much, with one study showing that as much as 80 percent of patients woken up during their Rapid Eye Movement (REM) sleep phase can remember their own dreams.  

While Halls says that the best chances for dream recall are with dreams that occur during REM sleep, she cautions that “it’s important to remember that not all dreams take place during REM sleep, and some people may be able to recall their dreams even if they occurred while they were sleeping lightly or even in non-REM sleep.” 

The Last Word From Sleepopolis 

With all that we know, the inner workings of dreams and their purpose are still largely a mystery. What we know is this; everyone dreams, some can recall their dreams, and some cannot. We also know that sometimes the lines between dreams and memories become blurred. Our memories can find their way into our dreams, and our dreams can distort our memories. 

Sharon Brandwein

Sharon Brandwein

Sharon Brandwein is a Certified Sleep Science Coach and a freelance writer. She specializes in health and beauty, parenting, and of course, all things sleep. Sharon’s work has also appeared on ABC News, USAToday, and Forbes. When she’s not busy writing, you might find her somewhere curating a wardrobe for her puppy.