Dreams are images, emotions, or sensations brains produce during sleep. While dreaming can occur during any stage of the [sleep cycle](https://www.masterclass.com/articles/stages-of-sleep-explained), rapid eye movement sleep (also known as [REM sleep](https://www.masterclass.com/articles/rem-sleep-guide)) produces the most memorable and vivid dreams. There are many [types of dreams](https://www.masterclass.com/articles/types-of-dreams-explained), including healing, prophetic, recurring, lucid, and nightmares. You can have multiple dreams per sleep session, which can be as short as ten seconds and as long as forty-five minutes.

> “Dreams are visual. They're filled with motor activity. We tend to be doing things. Are they filled with past autobiographic memories? Yes, very often. Are dreams sometimes emotional? They can be, very much so. Are dreams irrational, illogical, or bizarre? Yes, very much. And so brain science has given us the first neural evidence for describing the way in which we experience this strangest of all things called the dreaming state.” — Matthew Walker
There is no clear scientific explanation for the function of dreams, but there is a range of theories. Sleep expert Matthew Walker says, “The origin of dreams or the belief of where dreams come from has a very storied history and past.” The study of dreams is a large and growing field of scientific inquiry, and theories continue to emerge from neuroscience, psychology, psychiatry, and cognitive science. Some notable examples of dream theories include:

1. __Emotional processing__: One theory is people dream to process emotions. Dreams can often be emotionally charged, and by dreaming, people might work through emotional challenges and better prepare themselves for the difficulties of everyday life.
2. __Learning assistance__: Some researchers suggest the purpose of dreams is to learn new skills and sharpen [problem-solving](https://www.masterclass.com/articles/creative-problem-solving) abilities. When a person focuses on learning a new skill or working through a challenging problem, they might dream about the activity to help them complete the task.
3. __Memory consolidations__: Another dream theory holds dreams are instrumental in forming new memories. While the precise mechanism remains mysterious, some sleep experts believe dreaming in the REM stage helps the brain consolidate short-term memories and store them as long-term memories.
4. __Mental organizing__: Some sleep experts believe dreaming is a way to organize mental space. During sleep, a person’s mind sifts through the sensory data they encountered while they were awake, making important neural connections where necessary and editing out extraneous information.
5. __Otherworldly <a href='https://masterclass.com/articles/robin-robertss-tips-for-effective-communication' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://masterclass.com/articles/robin-robertss-tips-for-effective-communication","linkCopy":"communication","category":"automated-link"}' automatic='true'>communication</a>__: Many religious traditions maintain dreams are a way to connect with other worlds or dimensions. Many believe dreamed encounters with departed loved ones contain great significance. “Back in ancient Roman and Greek times, they believed that our dreams were being gifted to us from on high, from in the heavens, from specific gods,” Matthew says. “And then other cultures, for example, Eastern Asian cultures, believed that dreams were coming from somewhere in our soul, perhaps somewhere in our body.” 
6. __Random noise__: Some researchers believe dreams don’t have any particular purpose and are a byproduct of an active brain. This random brain activity might not have any other special purpose.
7. __Unconscious desires__: Austrian psychotherapist Sigmund Freud’s theory posits dreams are expressions of the unconscious mind’s desires. If people cannot express desires in their waking life, the unconscious mind might enact them as fantasies during sleep. “[Freud] made, in some ways, the science of dreaming a brain science [or] a neuroscience,” Matthew says. “Because it was Freud who suggested that it was somewhat in the mind of each of us that our dreams were coming from. That was the repository of dreaming.”
People can have several types of dreams. While the possibilities are limitless, some common categories include:

1. __Flying dreams__: Many people dream they can fly. These dreams are often pleasant and even euphoric. Dreamers might associate these dreams with sensations of freedom, fearlessness, and empowerment.
2. __Lucid dreams__: The sleeper becomes aware they are dreaming while in a lucid dreaming state and can retain some control of their body and thoughts within the dream.
3. __Nightmares__: These are fear-inducing dreams. In this case, the dream state might be the brain’s way of processing daily stressors. Common causes of nightmares or bad dreams include poor eating habits, traumatic events, illness, [sleep deprivation](https://www.masterclass.com/articles/sleep-deprivation), [sleep disorders](https://www.masterclass.com/articles/sleep-disorders-explained), or medication.
4. __Prophetic dreams__: In prophetic dreams, people see future events occur before they happen in real life. Some believe these dreams mean a person has predicted the future, while others believe prophetic dreams are the subconscious preparing you for a likely outcome.
5. __Recurring dreams__: These are dreams a person repeatedly experiences over a sleep session or multiple sleep sessions. Recurring dreams contain the same or similar imagery and sensations in prior occurrences and can also occur as recurring nightmares. Various theories suggest that recurring dreams result from risk avoidance, internalized fears, or other unresolved issues.
6. __Stress dreams__: Another common dream phenomenon involves stress. While not outright nightmares, stress dreams are often tense and unpleasant. Many people report dream content that involves tests for which they are unprepared or other situations that are confusing or difficult.
Everyone dreams at night, but few people can remember their dreams. Consider the following tips for recalling your dreams:

- __Establish a good sleep routine__. Having a regular bedtime and waking time is a good way to practice healthy [sleep hygiene](https://www.masterclass.com/articles/sleep-hygiene-tips), which might help you recall your dreams.
- __Focus on recall right after waking__. The memory of a dream fades fast, so you are most likely to recall your dreams right after you wake up. 
- __Keep a dream journal__. By recording your sleep stories in a [dream journal](https://www.masterclass.com/articles/how-to-keep-a-dream-journal), you will [build a habit](https://www.masterclass.com/articles/how-to-build-a-habit) of recalling your dreams more often. As you write down the details of your dreams, you might strengthen your ability to remember even more.
- __Wake up gently__. If you wake up abruptly, you are likely to jolt into your waking mindset, and any fragments that might remain of your dreams will quickly disperse. Try using an alarm clock that has gentle sounds. Soft, low-volume music or voices can also assist in a smoother transition to waking life, making dream recall easier.
Saw some of the best darn logs of your life with a [MasterClass Annual Membership](https://www.masterclass.com) and exclusive instructional videos from Dr. Matthew Walker, the author of *Why We Sleep* and the founder-director of the Center for Human Sleep Science at the University of California, Berkeley. Between Matthew’s tips for optimal snoozing and info on discovering your body’s ideal rhythms, you’ll be sleeping more deeply in no time. 
There are several theories about why people dream, but there is no scientific explanation for the function of dreams. Learn about various dream theories and how to retain your dreams.

There are several theories about why people dream, but there is no scientific explanation for the function of dreams. Learn about various dream theories and how to retain your dreams.

Why Do We Dream? 7 Dream Theories

Dreams are images, emotions, or sensations brains produce during sleep. While dreaming can occur during any stage of the <a href='https://www.masterclass.com/articles/stages-of-sleep-explained' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/stages-of-sleep-explained","linkCopy":"sleep cycle","category":null}'>sleep cycle</a>, rapid eye movement sleep (also known as <a href='https://www.masterclass.com/articles/rem-sleep-guide' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/rem-sleep-guide","linkCopy":"REM sleep","category":null}'>REM sleep</a>) produces the most memorable and vivid dreams. There are many <a href='https://www.masterclass.com/articles/types-of-dreams-explained' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/types-of-dreams-explained","linkCopy":"types of dreams","category":null}'>types of dreams</a>, including healing, prophetic, recurring, lucid, and nightmares. You can have multiple dreams per sleep session, which can be as short as ten seconds and as long as forty-five minutes.<blockquote class="mc-text--italic mc-opacity--hinted mc-my-8 mc-mr-0 mc-ml-6 mc-pl-6">“Dreams are visual. They&#39;re filled with motor activity. We tend to be doing things. Are they filled with past autobiographic memories? Yes, very often. Are dreams sometimes emotional? They can be, very much so. Are dreams irrational, illogical, or bizarre? Yes, very much. And so brain science has given us the first neural evidence for describing the way in which we experience this strangest of all things called the dreaming state.” — Matthew Walker</blockquote>

What Are Dreams?

There is no clear scientific explanation for the function of dreams, but there is a range of theories. Sleep expert Matthew Walker says, “The origin of dreams or the belief of where dreams come from has a very storied history and past.” The study of dreams is a large and growing field of scientific inquiry, and theories continue to emerge from neuroscience, psychology, psychiatry, and cognitive science. Some notable examples of dream theories include:<ol class="mc-m-4"><li class="mc-my-4"> 1. Emotional processing: One theory is people dream to process emotions. Dreams can often be emotionally charged, and by dreaming, people might work through emotional challenges and better prepare themselves for the difficulties of everyday life. </li><li class="mc-my-4"> 2. Learning assistance: Some researchers suggest the purpose of dreams is to learn new skills and sharpen <a href='https://www.masterclass.com/articles/creative-problem-solving' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/creative-problem-solving","linkCopy":"problem-solving","category":null}'>problem-solving</a> abilities. When a person focuses on learning a new skill or working through a challenging problem, they might dream about the activity to help them complete the task. </li><li class="mc-my-4"> 3. Memory consolidations: Another dream theory holds dreams are instrumental in forming new memories. While the precise mechanism remains mysterious, some sleep experts believe dreaming in the REM stage helps the brain consolidate short-term memories and store them as long-term memories. </li><li class="mc-my-4"> 4. Mental organizing: Some sleep experts believe dreaming is a way to organize mental space. During sleep, a person’s mind sifts through the sensory data they encountered while they were awake, making important neural connections where necessary and editing out extraneous information. </li><li class="mc-my-4"> 5. Otherworldly <a href='https://masterclass.com/articles/robin-robertss-tips-for-effective-communication' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://masterclass.com/articles/robin-robertss-tips-for-effective-communication","linkCopy":"communication","category":"automated-link"}' automatic='true'>communication</a>: Many religious traditions maintain dreams are a way to connect with other worlds or dimensions. Many believe dreamed encounters with departed loved ones contain great significance. “Back in ancient Roman and Greek times, they believed that our dreams were being gifted to us from on high, from in the heavens, from specific gods,” Matthew says. “And then other cultures, for example, Eastern Asian cultures, believed that dreams were coming from somewhere in our soul, perhaps somewhere in our body.” </li><li class="mc-my-4"> 6. Random noise: Some researchers believe dreams don’t have any particular purpose and are a byproduct of an active brain. This random brain activity might not have any other special purpose. </li><li class="mc-my-4"> 7. Unconscious desires: Austrian psychotherapist Sigmund Freud’s theory posits dreams are expressions of the unconscious mind’s desires. If people cannot express desires in their waking life, the unconscious mind might enact them as fantasies during sleep. “[Freud] made, in some ways, the science of dreaming a brain science [or] a neuroscience,” Matthew says. “Because it was Freud who suggested that it was somewhat in the mind of each of us that our dreams were coming from. That was the repository of dreaming.” </li></ol>

7 Dream Theories

People can have several types of dreams. While the possibilities are limitless, some common categories include:<ol class="mc-m-4"><li class="mc-my-4"> 1. Flying dreams: Many people dream they can fly. These dreams are often pleasant and even euphoric. Dreamers might associate these dreams with sensations of freedom, fearlessness, and empowerment. </li><li class="mc-my-4"> 2. Lucid dreams: The sleeper becomes aware they are dreaming while in a lucid dreaming state and can retain some control of their body and thoughts within the dream. </li><li class="mc-my-4"> 3. Nightmares: These are fear-inducing dreams. In this case, the dream state might be the brain’s way of processing daily stressors. Common causes of nightmares or bad dreams include poor eating habits, traumatic events, illness, <a href='https://www.masterclass.com/articles/sleep-deprivation' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/sleep-deprivation","linkCopy":"sleep deprivation","category":null}'>sleep deprivation</a>, <a href='https://www.masterclass.com/articles/sleep-disorders-explained' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/sleep-disorders-explained","linkCopy":"sleep disorders","category":null}'>sleep disorders</a>, or medication. </li><li class="mc-my-4"> 4. Prophetic dreams: In prophetic dreams, people see future events occur before they happen in real life. Some believe these dreams mean a person has predicted the future, while others believe prophetic dreams are the subconscious preparing you for a likely outcome. </li><li class="mc-my-4"> 5. Recurring dreams: These are dreams a person repeatedly experiences over a sleep session or multiple sleep sessions. Recurring dreams contain the same or similar imagery and sensations in prior occurrences and can also occur as recurring nightmares. Various theories suggest that recurring dreams result from risk avoidance, internalized fears, or other unresolved issues. </li><li class="mc-my-4"> 6. Stress dreams: Another common dream phenomenon involves stress. While not outright nightmares, stress dreams are often tense and unpleasant. Many people report dream content that involves tests for which they are unprepared or other situations that are confusing or difficult. </li></ol>

6 Types of Dreams

Everyone dreams at night, but few people can remember their dreams. Consider the following tips for recalling your dreams:<ul class="mc-m-4 list-styled"><li class="">Establish a good sleep routine. Having a regular bedtime and waking time is a good way to practice healthy <a href='https://www.masterclass.com/articles/sleep-hygiene-tips' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/sleep-hygiene-tips","linkCopy":"sleep hygiene","category":null}'>sleep hygiene</a>, which might help you recall your dreams. </li><li class="">Focus on recall right after waking. The memory of a dream fades fast, so you are most likely to recall your dreams right after you wake up. </li><li class="">Keep a dream journal. By recording your sleep stories in a <a href='https://www.masterclass.com/articles/how-to-keep-a-dream-journal' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-keep-a-dream-journal","linkCopy":"dream journal","category":null}'>dream journal</a>, you will <a href='https://www.masterclass.com/articles/how-to-build-a-habit' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-build-a-habit","linkCopy":"build a habit","category":null}'>build a habit</a> of recalling your dreams more often. As you write down the details of your dreams, you might strengthen your ability to remember even more. </li><li class="">Wake up gently. If you wake up abruptly, you are likely to jolt into your waking mindset, and any fragments that might remain of your dreams will quickly disperse. Try using an alarm clock that has gentle sounds. Soft, low-volume music or voices can also assist in a smoother transition to waking life, making dream recall easier. </li></ul>

How to Remember Dreams

Saw some of the best darn logs of your life with a <a href='https://www.masterclass.com' target='_blank' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com","linkCopy":"MasterClass Annual Membership","category":null}'>MasterClass Annual Membership</a> and exclusive instructional videos from Dr. Matthew Walker, the author of Why We Sleep and the founder-director of the Center for Human Sleep Science at the University of California, Berkeley. Between Matthew’s tips for optimal snoozing and info on discovering your body’s ideal rhythms, you’ll be sleeping more deeply in no time.

Want to Learn More About Catching Those Elusive Zs?

There are several theories about why people dream, but there is no scientific explanation for the function of dreams. Learn about various dream theories and how to retain your dreams.

There are several theories about why people dream, but there is no scientific explanation for the function of dreams. Learn about various dream theories and how to retain your dreams.
