The Purpose of Dreams

The purpose of dreams has been a subject of speculation for thousands of years. Greek philosopher Aristotle believed that dreams occurred because of residual movements of sensory organs, while psychiatrist Sigmund Freud considered dreams the “royal road to the unconscious,” theorizing that dreams were a manifestation of repressed desires. (1) (2) (3) No doubt, the science of sleep and dreams has come a long way since Freud and Aristotle, but the question: “Why do we dream?” remains. Theories about the purpose of dreams abound and continue to evolve — here’s what we know. 

Long Story Short

• While we still can’t pinpoint the exact purpose of dreams, there are plenty of theories to go around.
• Theories on the purpose of dreams range broadly, with some experts believing they’re simply a random firing of neurons, others thinking of them as a dress rehearsal for stressful situations, and more.
• Dreams can be beneficial for emotional and cognitive functioning, but not all dreams have meaning.

When Do We Dream? 

Dreams are a collection of visual images and involuntary thoughts that occur during sleep. Dream content can stir up a range of emotions, and while some dreams can have a narrative, others make no sense to the dreamer upon waking. (4) (5) While some people may not remember these experiences, everyone dreams. Although the duration varies from person to person, people typically spend around two hours out of each night in the dream world. (6)

Early research suggested that dreams were limited to REM sleep; however, new research suggests they can and do occur in all stages of non-REM sleep. (7) Moreover, dreaming and recall rates may differ depending on which stage of sleep they occur in. REM dreams tend to be longer, more hallucinatory, and have higher recall rates, while dreams outside of REM tend to be less vivid and poorly recalled. (8)

Why Do We Dream? 

According to Dr. Jade Wu, a board-certified behavioral sleep medicine psychologist and researcher at Duke University School of Medicine, there isn’t a full scientific consensus on why we dream. However, research suggests the purpose of dreams may be: (9) (10) (11)

• Emotion regulation
• Memory consolidation 
• Information processing 
• Problem-solving 
• Reverse-learning unimportant information 

Benefits of Dreaming 

Laura Purdy, M.D., MBA, and board-certified family medicine physician, says, “We all know the great benefits of good sleep for the body, but it is harder to dive into the role of dreams.” She goes on to say that “If we look at the many theories on the purpose of dreams, it stands to reason that the benefits of dreaming lie in their ability to help us process emotions, thoughts, and feelings and build and consolidate memories.” (9)

More specifically, Purdy adds that we consider “dreams as a means of expressing feelings and emotions that our conscious selves aren’t expressing; the benefit lies in their ability to help us sort through some more painful or complicated feelings.

Wu notes, “When dreams are pleasant, people tend to feel good after dreaming because it presents possibilities for imagination and wish fulfillment.” She also highlights the fact that “some types of dreams, such as lucid dreaming, have also been used as therapy to improve mood and decrease symptoms of PTSD.” (12) 

Do Dreams Have Meaning? 

According to psychotherapist Noah Kass, “The answer depends on whom you ask. Historically, cultures have assigned significance to dreams, seeing them as omens, divine messages, or expressions of inner desires.” Kass notes, “Ancient Egyptian priests viewed dreams as messages from the gods, while Greek philosophers and oracles saw them as insights into the subconscious and prophetic messages.” 

He adds, “Sigmund Freud believed dreams reveal hidden desires and unresolved conflicts, while Carl Jung proposed that dreams facilitate communication between the conscious and unconscious minds, helping to balance our psyche.” (3) (13) Bringing the timeline to modern day, Kass says, “Some see dreams as reflections of inner thoughts and emotions, while others consider them spontaneous neural activity without meaning.”  

Similarly, Wu tells us that dreams can incorporate physical sensations when you’re sleeping, the emotions you experience during the day, or the worries on your mind. (14) They may help you understand your emotions, but they don’t necessarily have meaning in the sense that they predict events that will happen, reveal secrets, or reflect deep desires that we’re not aware of. (15)

What Do Frequent Nightmares Mean? 

According to Kass, frequent nightmares may be the result of past trauma. “People with frequent nightmares may often experience constant daily stress or have a history of significant trauma. (16) It is as if those historical, traumatic experiences that have left an imprint, and recurring nightmares are attempts to manage the unresolved daily emotions that build up in them.” 

Frequent nightmares can also fall under the threat simulation theory of dreams, in which the dreamer essentially experiences recurring scenarios as a means of rehearsing their response to real-life situations (more on that below). (17)

Nightmares may also be caused by medications and other mental health disorders, such as depression or schizophrenia. (18)

Theories of Dreams

“The original psychological theory on the purpose of dreams is from Freud, who believed that dreaming was a way to express unconscious desires,” says Wu. “Since then, there have been updated theories that take our new knowledge of neuroscience into account, and the full truth may be a combination of the following: 

The AIM Theory of Dreaming

J. Allan Hobson developed the AIM Theory of Dreaming (also known as the Activation synthesizer theory), which he first presented in 1978. (19) Wu says, “This theory proffers that dreaming is just the by-product of random firings in the brain during REM when it’s trying to organize and prune emotions and memories.” Any stories that sleepers come away with are just a result of them waking up and constructing a narrative to make it make sense. 

The Threat Simulation Theory of Dreaming

Finnish cognitive neuroscientist Antti Revonsuo developed the Threat Simulation Theory of dreaming, which suggests that dreams serve an evolutionary purpose and are directly related to human survival. According to Wu, this theory posits that “The brain simulates possible scenarios, including threats, problems, and fight-or-flight situations during the sleep state, so as to rehearse possible solutions and responses.” (20)

Experts suggest that Revonsuo’s theory may hold water, considering that threatening themes are common in dreams across cultures and include: (21)

• Drowning
• Being chased
• Being trapped
• Being naked
• Falling
• Being late
• Poor performance

The Contemporary Theory of Dreaming 

Developed by Ernest Hartmann, professor of psychiatry at Tufts University School of Medicine, The Contemporary Theory of Dreaming suggests that dreams are not random firings of neurons but are instead shaped by the emotions of the dreamer. In support of this idea, some studies have shown that dream imagery is more focused, and the intensity of dreams is greater after trauma events. (22) (23)

The Expectation Fulfillment Theory of Dreaming

Contemporary researcher and psychologist Joe Griffin believes that dreams are metaphors that represent emotional “arousals,” instincts, or feelings that may not be appropriate or safe to act on during the day. His expectation fulfillment theory suggests that dreaming helps resolve emotions and human drives not adequately expressed during waking hours. (24)

The Overnight Therapy Theory of Dreaming

With a more novel theory on the purpose of dreams, neuroscientist, professor at the University of California at Berkeley, and author of Why We Sleep, Matthew Walker, believes that sleep is essential not just for the healing of physical wounds but also of psychic ones. (25) 

Existing research reveals that noradrenaline, a molecule associated with anxiety, is absent from the brain during REM sleep when dreams are most likely to occur. (26) At the same time, centers of memory and emotion are activated. (27) This may mean that memories and emotions are being processed in an environment free from stress and anxiety. Furthermore, Walker theorizes that diminishing emotional reactivity in waking hours may be one of the primary functions of dreaming. (18)

FAQs

The Last Word From Sleepopolis 

There is a wide range of theories regarding the purpose of dreams and research into the question, “Why do we dream? seems to be ongoing. While we may not have a one-and-done answer, we can say this: dreaming may serve more than one purpose. Ultimately, these nightly story snippets and flashes of imagery may be beneficial to our emotional health and well-being. If you’re concerned about the nature of your dreams or the frequency of nightmares, you might consider speaking with a qualified professional to help sort things out so you can get back to sleep. 

Sources

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Kass, Noah. Personal Interview. June 10, 2024

Purdy, Laura. Personal Interview. June 12, 2024

Wu, Jade. Personal Interview. June 11, 2024