Dreams: Types, Science, and Meanings

By Mark Thompson

Mar 22nd, 2021

Dreams are images, ideas, emotions and sensations that occur involuntarily in the mind during sleep. They can last from as little as a few seconds to as long as 20 minutes, and the average person has at least three to five, and often many more, dreams a night (dreams typically occupy a total of about two hours of a normal night’s sleep).

Unfortunately, no-one has ever been able come up with a way to record or visualize dreams (although some recent research is beginning to show promise in that area), so we must resort to the low-tech and rather unscientific solution of waking people and asking them whether they were dreaming, and what about.

What are Dreams?

A dream is a story, selection of images, or thoughts that play out in our minds while we sleep. Sometimes we remember these dreams when we wake up, but sometimes we don’t. Regardless of whether or not we remember it, it is thought that everyone dreams every night.

What Is a Standard Dream?

If we’re going to talk about different types of dreams, we should probably define a “standard” dream to compare all the different types to. A standard dream happens after you have fallen asleep, and is typically made up of images that go together to create a story. Some dreams include other sensations, like sound and textures, and the dreamer is often emotionally involved in the dream. Oftentimes this story makes very little logical sense once you wake up and think about it, but while you are dreaming you don’t question it.

What Are the Features of Dreams?

Dreams are made up of a few key components:

  • A regular dream takes place while you are fully asleep.
  • Dreams involve the recreation of certain physical stimuli, whether they are visual, auditory, tactile, etc.
  • Dreams are like a story being told to you; you do not have control over what happens.
  • You might remember your dream when you first wake up, but by the end of the day, the memory is faded, if not completely gone.
  • Emotions are a very normal feature in dreams. The most common emotions while dreaming are fear, anxiety, and surprise.
  • Even if dreams don’t make sense, you do not question their logic while you’re dreaming.

Why Do We Dream?

That’s a great question, one that people have been asking since Sigmund Freud was popular. Unfortunately, we still don’t have a straight answer, but we do have an abundance of theories. According to the activation-synthesis model developed in the 1970s by J. Allan Hobson and Robert McClarley, dreams are nothing more than our brain’s attempts to make sense of the random brain activity going on at night. Eugen Tarnow, creator of the long-term memory excitation theory would disagree, saying that dreams aren’t completely random.

Instead, they reflect randomly selected long-term memories. Another theory comes from Jie Zhang who came up with the continual-activation theory of dreams in 2004, which says that our working memory must be firing at all times, and this results in dreams at night. Zhang believes that we process procedural memories (memories on how to do things, like bake a pie or ride a bike) during rapid eye movement (REM) sleep and we process declarative memories (memories of specific people or events) during non-REM sleep.

Regardless of the science behind why we dream, studies have shown that dreaming can improve our memory, problem-solving abilities, and emotional processing skills.

Types of Dreams

Sexual fantasies can and do appear in dreams, but not to anything like the extent popularly thought (between 8%-10% according to some estimates, and more common in young to mid-teens). By some estimates, at least 40%, and perhaps as much as 75%, of normal dream content is negative in nature, although only a small minority of these would be characterized as nightmares.

Whatever the subject matter, though, dreams are always egocentric, involving ourselves as a principal character. Despite this, we have no control over the story-line of a dream, and generally we are not even aware that we are dreaming (except in the case of lucid dreams).

Most people dream in color, but some people do dream in black and white. Interestingly, much fewer people report dreaming in black and white now than did 50 years ago (when television was black and white), and most of those that do still claim to dream in black and white are of an age to remember black and white television.

This has led some to conclude that media exposure as a child influences, or perhaps in some way reconstructs, our dreams (or at least our memories of dreams). However, it is impossible to objectively verify such reports, and it is difficult to draw any firm conclusions about them.

What are Nightmares?

Nightmares are a lot like regular dreams, except their content is often disturbing or upsetting, inspiring fear, disgust, and pain in the dreaming mind. Typically, nightmares cause the dreamer to wake, and upon waking, people typically have great dream recall for nightmares. You can remember exactly how terrifying it was and what happened, and you may find it hard to go back to sleep.

Like regular dreams, researchers aren’t entirely sure what causes nightmares, although studies have found that people with mood disorders like bipolar or depression are more likely to experience nightmares. People with post-traumatic stress disorder (PTSD) are also more likely to have nightmares, except they may be less nonsensical. Instead, PTSD nightmares may involve reliving traumatic events like a terrifying car crash or childhood abuse.

Even if you don’t have a mental illness, you still might experience nightmares. Some scientists believe they can be caused by the stress of daily life, eating too many carbs before bed, or drinking caffeine or alcohol too close to bedtime.

What are Night Terrors?

Night terrors might sound a lot like nightmares, but they are very different. Night terrors often produce a very physical response in the dreamer, such as screaming or thrashing around before finally waking from the night terror. Unlike nightmares, the dreamer rarely remembers the content of dreams that involve night terrors, and rarely get stuck in a state of wakefulness afterward. You would think all that screaming would keep them awake after, but many people who experience night terrors fall asleep quickly afterward.

Night terrors are much more common in children than in adults, though that doesn’t mean adults never have them. Night terrors also tend to happen shortly after falling asleep because they take place during non-REM dreaming which takes place largely at the beginning of the sleep cycle, while nightmares are a form of REM-dreaming.

What are Lucid Dreams?

Lucid dreams are dreams in which, contrary to the normal situation, the sleeper is actually aware of dreaming, or at least that some event taking place in the dream cannot possibly be really happening. These dreams are generally extremely realistic and vivid. Usually, people automatically wake themselves up when they actually realize that they are dreaming, but it may be possible to consciously continue the dream. According to some people, it may even be possible to exert some control over the dream content, to become an active participant in the dream, making decisions and influencing outcomes.

Some go even further, claiming that it is possible to train oneself to experience lucid dreams, although these are more contentious claims. It is thought that, in the case of lucid dreams, the lateral prefrontal cortex of the brain (the part associated with logic and common sense which is normally suppressed during REM sleep) is for some reason not suppressed, so that the dreaming and logic circuits are both active at the same time.

However, there does still seem to be some interface with the rest of the waking brain during lucid dreaming. An early researcher on the subject, the 19th Century French aristocrat Marquis d’Hervey de Saint-Denys, repeatedly tried to dream his own death by directing his lucid dreams towards suicide, but found that the dreams always changed scene and avoided the death. It also appears to be impossible to tickle onself or make oneself laugh in a lucid dream, suggesting a high level of awareness of bodily actions and sensations.

What are Recurring Dreams?

Recurring dreams are dreams that repeat themselves night after night with little variation. They may be positive in nature, but more often they have a nightmare-ish quality. The recurrence is thought to be because some conflict depicted by the dream (e.g. some life situation or emotional problem) remains stubbornly unresolved.

What are Daydreams?

Daydreaming refers to a level of consciousness somewhere between sleep and wakefulness, a mild detachment from immediate surroundings often referred to in psychology as dissociation. As the mind begins to wander during lulls in concentration throughout the day, the level of conscious awareness can decrease and the imagination may create all manner of (usually pleasant and positive) imagined scenarios and fantasies, all without consciousness sinking to the level of actual sleep.

A 2009 neurological study indicates that as much as half of our day-to-day thoughts are what are generally referred to as daydreams, and that more of our supposedly focussed thinking is interrupted and unstructured than we are wont to think.

Recent research is also attaching more and more importance to daydreaming. It claims that a wandering unfocused mind is the brain’s default mode, to which it automatically tries to return given the opportunity. It even claims that some of our best thinking occurs when our minds are allowed to wander.

During these daydreaming episodes, our minds are more likely to tackle ongoing intractable life problems that we may be unwilling to work through in a more focussed way, thus providing an essential element of stress reduction. It also provides an opportunity for creativity and the incubation of new ideas without the usual inhibitory brake of our rational and prudent prefrontal cortex.

Other Types of Dreams

Nightmares, night terrors, lucid dreams, recurring dreams and daydreams are different from the standard dream, but they’re still fairly common. Now we’re going to dig into some of the more unusual dream types, like healing dreams prophetic dreams, and more.

Vivid Dreams

Vivid dreams are exactly what they sound like: dreams that are incredibly vivid and may be difficult to distinguish from real life in your memories. They might be incredibly detailed and realistic, or they might be very bizarre but nonetheless feel absurdly real. According to research by the National Sleep Foundation, vivid dreams are more common among people with narcolepsy.

Healing Dreams

Healing dreams have not been researched by the National Sleep Foundation or similar scientific organizations, but in the spiritual community, they are a very real type of dream that can bring peace to people who are struggling in a variety of ways. Healing dreams may include the presence of some kind of deity or spirit, they might bring a resolution that has been thus-far elusive, or they may be dreams of guidance. Scientific research suggests that dreams are vital for emotional processing, so healing dreams could definitely be a real, powerful type of dream.

False Awakenings

If you’ve ever woken from a dream, gone on with your day, only to suddenly wake up again, you’ve experienced a false awakening. False awakenings occur when someone believes they have woken up, but they’re really still sleeping. Sometimes people realize they’re in a false awakening because their digital devices don’t work correctly or something about their environment feels “off.” False awakenings may be related to lucid dreaming, but the research in that area is still in its preliminary stages.

Prophetic Dreams

Prophetic dreams are also sometimes called precognitive dreams, and they involve dreaming about something that hasn’t happened yet, but does happen later. If you don’t pay close attention to your dreams, you may experience a sense of deja vu when the event you dreamed about happens in real life. Like healing dreams, there is not a lot of scientific research on prophetic dreams, but that does not automatically rule out their existence.

The Science Behind Dreaming

Dreams can occur in almost all stages of sleep, but they are most common during REM sleep, particularly towards the end of the sleep period, and the dreams experienced during this sleep stage tend to be more vivid, detailed, memorable and often bizarre.

During REM sleep, there is an almost complete loss of muscle tone and skeletal muscle activity (known as atonia), and it has been speculated that this paralysis may be a built-in mechanism to protect the dreamer from any injuries that might occur if they were to physically act out the vivid, and often violent, content of REM dreams.

This may also account for the commonly-experienced dreams in which we feel unable to move or can only move sluggishly in response to a threat. Studies during the 1970s showed that, where REM sleep is denied to sleepers, dreams assert themselves anyway, either during other sleep stages or even intruding themselves into daytime wakefulness, suggesting that the urge to dream is so strong that the brain seeks to compensate for its loss.

There is also a phenomenon called dream incorporation, in which outside stimuli can be incorporated into the narrative of dream imagery. William C. Dement and others did many experiments on this subject back in the 1950s and 1960s. Examples might be a dream about braving Arctic conditions caused by the bedcovers slipping off, the incorporation of particular friends into a dream in response to the prompting of the friends’ names, the incorporation of a phone or alarm clock’s ringing into a dream, etc. Often the stimuli are changed or twisted in some way, but still recognizable. Some scientists believe that this represents the body’s way of protecting and extending REM sleep despite external interferences.

Who Dreams?

Everyone dreams every night, from early childhood until the day we die, regardless of whether or not they can remember those dreams. Memories of dreams are very unstable, and tend to disappear completely within a few minutes of waking, unless we make a deliberate attempt to remember them, or write them down.

In experiments, up to 80% of adult sleepers woken during REM sleep can remember at least some of their dreams. Light sleepers tend to be able to remember their dreams more easily than deep sleepers. Some people can never remember their dreams, regardless of when they were woken.

Although it is known that babies spend long hours of the day and night in REM sleep (and even more in utero), it is still not known exactly when they actually start to dream. Young children do definitely dream, although only about 20% of 7-year olds report dreams when woken from REM sleep, as compared to around 80% of adults, even though they spend substantially more time in REM sleep than adults.

The dreams of young children usually tend to be quite static and plain, featuring few characters and social interactions, and little in the way of strong emotions. Many childhood dreams are “primal” or atavistic in nature, similar to the kinds of dreams mankind may have experienced millennia ago.

At first, they may not even include the dreamer as a major participant, although by the age of about seven that starts to change. It is hypothesized that it is the development of mental imagery and visuo-spatial skills, rather than verbal or memory capabilities, that allows children to begin to experience complex and personalized dreams.

Blind people also dream, just like everyone else, but, if they were born blind and have therefore never seen the world around them, the visual aspect of dreams tends to be lost. Their dreams are largely made up of sounds, tactile sensations and smells, senses which are often very highly developed in blind people.

Other mammals and, to a lesser degree, birds also appear to dream, in that they go through the same physiological processes as humans (REM brain-wave patterns and eye movements, twitches, etc). It is thought, however, that reptiles, fish and insects, with their simpler brain processes, do not dream.

Dream Interpretation: What do Dreams Mean?

Do you ever have a dream that was just so weird you wondered what it could possibly mean? There are many tropes that occur in many people’s dreams like teeth falling out, flying, or standing naked in front of a large audience.

Theorists have worked to uncover the answer to the question, What do dreams mean? Like all things related to dreams, there is no one singular answer to this question. Dream interpretation theory works to relate themes of dreams to common fears and desires related to the human experience.

Remember when you would read books in high school and have to figure out what it all means? In the same way that your English teacher could find various meanings in a books themes, dream theorists find many meanings in certain dreams.

One way to start exploring your dreams and their meanings is to record your dreams in a journal. A dream journal can help you recognize patterns in your dream and see if they correlate with anything going on in your life.

If you want to take a closer look at your dreams and what they mean, you can try your hand at dream interpretation. There are many psychological, spiritual, and humorous guides out there to help you, but here are some basic guidelines for common themes in our dreams:

  • Being Chased: Dreams about being chased typically mean something is trying to catch up to you, which means you may be practicing avoidance. It might be a stressor, a past trauma, or even a part of yourself that you’re refusing to acknowledge.
  • Falling: Dreams where you’re falling may have less to do with dream interpretation and more to do with physiology. When we fall asleep and our blood pressure falls, sometimes it can make us feel like our bodies are falling too, which then jerks us awake.
  • Flying: Dreams about flying are usually seen in a very positive light. You’re independent, you’re free, you’re powerful. But you could also interpret the dream another way: as the story of Icarus. Your dreams may be warning you that you’re flying too close to the sun.
  • Death: Many people consider dreams about death to be prophetic dreams, but that may not be the case at all. Death represents an end. Try to analyze your dream to figure out what ending you might be anticipating or fearing.
  • Being Naked: If you’re having dreams where you suddenly look down and see that you’ve forgotten your pants, you might be worried about being overly vulnerable.
  • Teeth Falling Out: When our teeth fall out in our dreams, there are several possible interpretations. We may be worried about our physical appearance, or we might be facing insecurities in our communication abilities. These dreams also might just be a sign that you’re grinding your teeth at night and need a mouthguard.