Why do we dream? How do dreams provide insight into the mind? Are dreams relevant to waking life? From ancient times when dreams were considered to hold prophetic powers to the neurological phenomena studied today, dreams remain one of psychology’s most enduring mysteries. Although scientists continue to research the answers to these questions, they build their work on some commonly accepted dream theories.
The Nature of Dreams
Defined as a series of thoughts, visions or feelings, dreams arise several times per night during sleep.
As a process, sleep is cyclical. It occurs in five stages, each helping to further the body’s goal of bolstering and regenerating itself. While stages 1-4 are simply named as such, the fifth stage is called Rapid Eye Movement, or REM. It makes up about 20 to 25 percent of adult sleep.
The REM stage is the most common time of dreaming, explains the National Sleep Foundation. Dreams themselves usually last between a few seconds to 30 minutes in length. On average, people dream about four to six times per night, with adults dreaming about two hours for every eight hours of sleep.
In addition to its association with dreams, the REM stage is a time when the body processes information, creates memories and increases depleted chemicals, such as serotonin. Although the necessity of sleep has long been observed, only in recent history did people consider that dreams may also serve a utilitarian function.
Four Theories of Dreams
The past two centuries have given rise to four of the most commonly accepted dream theories.
Sigmund Freud and Wish-Fulfillment
The famous psychoanalyst Sigmund Freud was the first to suggest that dreams may serve a particular scientific purpose. He came to believe that dreams were often a form of wish-fulfillment, the American Psychoanalytic Association says. In a dream, a subject could act out desires he or she could not fulfill in waking life. Some types of dreams, however, proved problematic within this model, such as dreams involving punishment or traumatic events. These led Freud to believe that dreams sometimes served as a way for patients to express guilt or conquer trauma. All these conjectures played into Freud’s overall (and revolutionary) theory of dreams: that they were manifestations of unconscious workings of the brain.
Carl Jung: Dreams as Direct Mental Expressions
Although Freud and Carl Jung were contemporaries, they disagreed strongly (and famously) about the nature of dreams. Freud believed that dreams, by nature, disguised their meaning. In contrast, Jung believed that dreams were actually direct expressions of the mind itself. Dreams, he thought, expressed an individual’s unconscious state through a language of symbols and metaphors. This “language” was natural to the unconscious state, but difficult to understand because it varied so much from waking language. Notably, Jung also believed that universal archetypes (or images) intrinsic to all human consciousness existed within this language. He believed that dreams served two functions: to compensate for imbalances in the dreamers’ psyche, and to provide prospective images of the future, which allowed the dreamer to anticipate future events.
REM and Activation-Synthesis
Yet another theory arose with the discovery of REM. The Activation-Synthesis theory was conceived by Harvard professors Allan Hobson and Robert McCarley in the 1970s, explains Joe Griffin of the Human Givens Institute. Hobson and McCarley discovered that during REM sleep, electrical signals called electroencephalogram recordings, or EEGs, pass through the brain. They theorized that the brain naturally reacted by attempting to make sense of the random stimulus. Thus, dreams had no intrinsic meaning; they were just a side effect of the brain’s normal activity. While this theory was revolutionary at the time, the continual advancement of technology has led to tremendous revision of this theory.
Threat Simulation Theory
Finnish psychologist Antti Revonsuo is one of the latest researchers to suggest a convincing theory about the function of dreams. Revonsuo found that during REM sleep, the amygdala (the fight-or-flight section of the brain) actually fires in similar ways as it does during a survival threat. “The primary function of negative dreams,” he explains, “is rehearsal for similar real events, so that threat recognition and avoidance happens faster and more automatically in comparable real situations.” In other words, dreams are an evolutionary trait designed to help us practice being safe.
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There is no doubt that sleep is vital to living a healthy life. Not only is it key in maintaining a healthy lifestyle (in fact, those of us who are good about our sleep often have a healthier weight than those of us who struggle to sleep regularly), but it works wonders for your mental processes as well. Although most scientists still debate the specific reason for why sleep is so important, there are many theories that explain why we do it. During sleep, the brain is shown to actually restore and replenish energy stores for the next day, in addition to strengthening your immune system.
Sleep is also believed to be adaptive, having evolved to tune out the external world when the threat of danger is at a minimum. This explains why some animals sleep at night, others sleep during the day, and others sleep according to their own peculiar cycles. Only a few animals, such as frogs, exhibit states that cannot technically be considered sleep. Fun fact: Dolphins have uni-hemispherical sleep patterns, meaning that their individual cerebral hemispheres take turns sleeping!
Sleep is also extremely important for facilitating learning. Sleep strengthens neural connections, which are at the basis of learning. Studies have shown that in memory testing, participants perform better having slept in between tests than those who did not. Other studies have shown that during exam weeks, students experience an increased amount of REM sleep, supporting the idea that when a greater amount of mental consolidation is necessary, sleep, especially REM sleep, is vital to the brain and body.
So what exactly happens when we sleep? Most people can answer this pretty easily: Dreams happen when we sleep! However, many people don’t know that there are in fact two different types of dreams, REM dreams and non-REM dreams. The defining difference is that while REM dreams are often characterized by very bizarre and surreal events, non-REM dreams generally involve dull and mundane events. So, next time you wake up from a dream about folding your socks, you can be sure your were in the middle of non-REM sleep!
But what exactly are dreams? The theories to explain dreaming have many similarities to the theories that explain sleep. The first theory is called the activation-synthesis theory. This theory states that during sleep, random brain activity occurs. These random neural firings then activate parts of the brain that would normally be interpreting sensory input. As a result, your brain must find a way to make sense of this random brain activity by synthesizing it with previously stored memories. Evidence against this theory states that if this were true, our dreams would actually be much more bizarre than they already are and share even less similarities with waking life.
The second theory results from the work in the field of psychoanalysis done by Sigmund Freud. Freud presented the theories of manifest content and latent content. According to his research, dreams actually contain messages that are generally hidden from the conscious awareness but represent unconscious conflicts within the mind of the dreamer. This theory can be broken down into two parts: manifest content, which is how the dream actually manifests itself within the dreamer and how it is remembered once the dreamer wakes up, and latent content, which is what the dream symbolizes to the dreamer. Although there is no real support for Freud’s theory, it does offer an interesting insight into the endless ways the brain may be working and also how it could be interpreted.
And finally, the evolved threat-rehearsal theory contests that similar to how we have adapted to sleep at night, we have also evolved to experience dreams that simulate life-threatening situations thereby allowing people to rehearse, and also learn from, the particular situation. According to this theory, dreaming may in fact be a direct result of evolution. Several facts support this theory, specifically that dreaming is associated with the amygdala which is activated by real dangers.
While sleeping and dreaming have yet to be definitively defined, they are indicative of the endless possibilities behind the mystery of the human brain, which is pretty cool!
Cheers and sleep well.
Despite scientific inquiry, we still don’t have a solid answer for why people dream. Some of the most notable theories are that dreaming helps us process memories and better understand our emotions, also providing a way to express what we want or to practice facing our challenges.
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7 Theories on Why We Dream
What Is a Dream?
A dream includes the images, thoughts, and emotions that are experienced during sleep. Dreams can range from extraordinarily intense or emotional to very vague, fleeting, confusing, or even boring. Some dreams are joyful, while others are frightening or sad. Sometimes dreams seem to have a clear narrative, while many others appear to make no sense at all.
There are many unknowns about dreaming and sleep, but what scientists do know is that just about everyone dreams every time they sleep, for a total of around two hours per night, whether they remember it upon waking or not.
Beyond what’s in a particular dream, there is the question of why we dream at all. Below, we detail the most prominent theories on the purpose of dreaming and how these explanations can be applied to specific dreams.
How Do Scientists Study Dreams?
The question of why we dream has fascinated philosophers and scientists for thousands of years. Traditionally, dream content is measured by the subjective recollections of the dreamer upon waking. However, observation is also accomplished through objective evaluation in a lab.
In one study, researchers even created a rudimentary dream content map that was able to track what people dreamed about in real time using magnetic resonance imaging (MRI) patterns. The map was then backed up by the dreamers’ reports upon waking.
The Role of Dreams
Some of the more prominent dream theories contend that the function of dreaming is to:
- Consolidate memories
- Process emotions
- Express our deepest desires
- Gain practice confronting potential dangers
Many experts believe that we dream due to a combination of these reasons rather than any one particular theory. Additionally, while many researchers believe that dreaming is essential to mental, emotional, and physical well-being, some scientists suggest that dreams serve no real purpose at all.
The bottom line is, while many theories have been proposed, no single consensus has emerged on why we dream.
Dreaming during different phases of sleep may also serve unique purposes. The most vivid dreams happen during rapid eye movement (REM) sleep, and these are the dreams that we’re most likely to recall. We also dream during non-rapid eye movement (non-REM) sleep, but those dreams are known to be remembered less often and have more mundane content.
Dreams May Reflect the Unconscious
Sigmund Freud’s theory of dreams suggests that dreams represent unconscious desires, thoughts, wish fulfillment, and motivations. According to Freud, people are driven by repressed and unconscious longings, such as aggressive and sexual instincts.
While many of Freud’s assertions have been debunked, research suggests there is a dream rebound effect, also known as dream rebound theory, in which suppression of a thought tends to result in dreaming about it.
What Causes Dreams to Happen?
In “The Interpretation of Dreams,” Freud wrote that dreams are “disguised fulfillments of repressed wishes.” He also described two different components of dreams: manifest content (actual images) and latent content (hidden meaning).
Freud’s theory contributed to the rise and popularity of dream interpretation. While research has failed to demonstrate that the manifest content disguises the psychological significance of a dream, some experts believe that dreams play an important role in processing emotions and stressful experiences.
Dreams Process Information
According to the activation-synthesis model of dreaming, which was first proposed by J. Allan Hobson and Robert McCarley, circuits in the brain become activated during REM sleep, which triggers the amygdala and hippocampus to create an array of electrical impulses. This results in a compilation of random thoughts, images, and memories that appear while dreaming.
When we wake, our active minds pull together the various images and memory fragments of the dream to create a cohesive narrative.
In the activation-synthesis hypothesis, dreams are a compilation of randomness that appear to the sleeping mind and are brought together in a meaningful way when we wake. In this sense, dreams may provoke the dreamer to make new connections, inspire useful ideas, or have creative epiphanies in their waking lives.
Dreams Aid In Memory
According to the information-processing theory, sleep allows us to consolidate and process all of the information and memories that we have collected during the previous day. Some dream experts suggest that dreaming is a byproduct, or even an active part, of this experience processing.
This model, known as the self-organization theory of dreaming, explains that dreaming is a side effect of brain neural activity as memories are consolidated during sleep. During this process of unconscious information redistribution, it is suggested that memories are either strengthened or weakened. According to the self-organization theory of dreaming, while we dream, helpful memories are made stronger, while less useful ones fade away.
Research supports this theory, finding improvement in complex tasks when a person dreams about doing them. Studies also show that during REM sleep, low-frequency theta waves were more active in the frontal lobe, just like they are when people are learning, storing, and remembering information when awake.
Dreams Spur Creativity
Another theory about dreams says that their purpose is to help us solve problems. In this creativity theory of dreaming, the unconstrained, unconscious mind is free to wander its limitless potential while unburdened by the often stifling realities of the conscious world. In fact, research has shown dreaming to be an effective promoter of creative thinking.
Scientific research and anecdotal evidence back up the fact that many people do successfully mine their dreams for inspiration and credit their dreams for their big “aha” moments.
The ability to make unexpected connections between memories and ideas that appear in your dreams often proves to be an especially fertile ground for creativity.
Dreams Reflect Your Life
Under the continuity hypothesis, dreams function as a reflection of a person’s real life, incorporating conscious experiences into their dreams. Rather than a straightforward replay of waking life, dreams show up as a patchwork of memory fragments.
Still, studies show that non-REM sleep may be more involved with declarative memory (the more routine stuff), while REM dreams include more emotional and instructive memories. In general, REM dreams tend to be easier to recall compared to non-REM dreams.
Under the continuity hypothesis, memories may be fragmented purposefully in our dreams as part of incorporating new learning and experiences into long-term memory. Still, there are many unanswered questions as to why some aspects of memories are featured more or less prominently in our dreams.
Dreams Prepare and Protect
The primitive instinct rehearsal and adaptive strategy theories of dreaming propose that we dream to better prepare ourselves to confront dangers in the real world. The dream as a social simulation function or threat simulation provides the dreamer a safe environment to practice important survival skills.
While dreaming, we hone our fight-or-flight instincts and build mental capability for handling threatening scenarios. Under the threat simulation theory, our sleeping brains focus on the fight-or-flight mechanism to prep us for life-threatening and/or emotionally intense scenarios including:
- Running away from a pursuer
- Falling over a cliff
- Showing up somewhere naked
- Going to the bathroom in public
- Forgetting to study for a final exam
This theory suggests that practicing or rehearsing these skills in our dreams gives us an evolutionary advantage in that we can better cope with or avoid threatening scenarios in the real world. This helps explain why so many dreams contain scary, dramatic, or intense content.
Dreams Help Process Emotions
The emotional regulation dream theory says that the function of dreams is to help us process and cope with our emotions or trauma in the safe space of slumber.
Research shows that the amygdala, which is involved in processing emotions, and the hippocampus, which plays a vital role in condensing information and moving it from short-term to long-term memory storage, are active during vivid, intense dreaming. This illustrates a strong link between dreaming, memory storage, and emotional processing.
This theory suggests that REM sleep plays a vital role in emotional brain regulation. It also helps explain why so many dreams are emotionally vivid and why emotional or traumatic experiences tend to show up on repeat. Research has shown a connection between the ability to process emotions and the amount of REM sleep a person gets.
Content similarities and common dreams shared among dreamers may help promote connection. Research also notes heightened empathy among people who share their dreams with others, pointing to another way dreams can help us cope by promoting community and interpersonal support.
Other Theories About Why We Dream
Many other theories have been suggested to account for why we dream.
- One theory contends that dreams are the result of our brains trying to interpret external stimuli (such as a dog’s bark, music, or a baby’s cry) during sleep.
- Another theory uses a computer metaphor to account for dreams, noting that dreams serve to “clean up” clutter from the mind, refreshing the brain for the next day.
- The reverse-learning theory suggests that we dream to forget. Our brains have thousands of neural connections between memories—too many to remember them all—and that dreaming is part of “pruning” those connections.
- In the continual-activation theory, we dream to keep the brain active while we sleep, in order to keep it functioning properly.
Lucid Dreaming
Lucid dreams are relatively rare dreams where the dreamer has awareness of being in their dream and often has some control over the dream content. Research indicates that around 50% of people recall having had at least one lucid dream in their lifetime and just over 10% report having them two or more times per month.
It is unknown why certain people experience lucid dreams more frequently than others. While experts are unclear as to why or how lucid dreaming occurs, preliminary research signals that the prefrontal and parietal regions of the brain play a significant role.
How to Lucid Dream
Many people covet lucid dreaming and seek to experience it more often. Lucid dreaming has been compared to virtual reality and hyper-realistic video games, giving lucid dreamers the ultimate self-directed dreamscape experience.
Potential training methods for inducing lucid dreaming include cognitive training, external stimulation during sleep, and medications. While these methods may show some promise, none have been rigorously tested or shown to be effective.
A strong link has been found between lucid dreaming and highly imaginative thinking and creative output. Research has shown that lucid dreamers perform better on creative tasks than those who do not experience lucid dreaming.
Stress Dreams
Stressful experiences tend to show up with great frequency in our dreams. Stress dreams may be described as sad, scary, and nightmarish.
Experts do not fully understand how or why specific stressful content ends up in our dreams, but many point to a variety of theories, including the continuity hypothesis, adaptive strategy, and emotional regulation dream theories to explain these occurrences. Stress dreams and mental health seem to go hand-in-hand.
- Daily stress shows up in dreams: Research has shown that those who experience greater levels of worry in their waking lives and people diagnosed with post-traumatic stress disorder (PTSD) report higher frequency and intensity of nightmares.
- Mental health disorders may contribute to stress dreams: Those with mental health disorders such as anxiety, bipolar disorder, and depression tend to have more distressing dreams, as well as more difficulty sleeping in general.
- Anxiety is linked to stress dreams: Research indicates a strong connection between anxiety and stressful dream content. These dreams may be the brain’s attempt to help us cope with and make sense of these stressful experiences.
A Word From Verywell
While there are many theories for why we dream, more research is needed to fully understand their purpose. Rather than assuming only one hypothesis is correct, dreams likely serve a variety of purposes.
Knowing that so much is left uncertain about why we dream, we can feel free to view our own dreams in the light that resonates best with us.
If you are concerned about your dreams and/or are having frequent nightmares, consider speaking to your doctor or consulting a sleep specialist.
