What do you know about your dreams?

As a sleep specialist, not a day goes by that I’m not talking to someone about their dreams. My patients, my kids, the guy who sells me my morning coffee—EVERYONE wants to know, “What do my dreams mean?” We’re all fascinated by dreams, and understandably so. 

Dreaming is a strange and mysterious process—one that scientists don’t even fully understand. Let’s take a closer look at the stuff of which dreams are made. 

Why do we dream? 

The why of dreaming is one of the great mysteries of sleep. There are many different theories about why dreaming happens. There are some scientists who think that dreaming has no specific underlying purpose, that our dreams might be a by-product of other things going on in the brain during sleep. But many scientists studying sleep and dreams believe there is a primary purpose to our dreams. Different theories suggest that dreams are: 

  • A way to process memory and learning, moving memories from short-term to long-term storage and giving the brain a clean slate before the next waking day
  • A way to maintain emotional balance, by working through difficult, complicated, unsettling thoughts, emotions, and experiences
  • A different state of consciousness that unites past, present and future—to process information from the first two, and prepare for the third
  • A kind of dress rehearsal for the brain, to prepare itself to face threats, dangers and challenges in waking life
  • The brain responding to biochemical changes and electrical impulses that occur during sleep

There may not be a single answer to why we dream. Our dreams might serve several purposes at once. 

What is a dream? 

At its most basic level, a dream is a collection of images, impressions, events and emotions that we experience during sleep.

Sometimes dreams have real storylines, with plots and characters that could be plucked from a movie screen. Other times dreams are more impressionistic, filled with emotions and visual imagery.

Typically, a person will spend two hours or more a night dreaming, experiencing somewhere between 3-6 dreams over the course of a night’s rest. Most dreams appear to last from 5-20 minutes.

I often hear people say, “I don’t dream.” You may not remember your dreams, but that doesn’t mean you’re not having them. Dreaming is a universal human experience. The truth is, the vast majority of dreams we experience will—for most of us—never be remembered. Memories of dreams usually fade very quickly after we awaken.

Why can’t I remember my dreams? 

The ability to recall dreams varies a lot from one individual to another. Some people can regularly remember their dreams, while others may have only hazy recollections of themes or subjects in their dreams—or no recollection at all.

There are a number of possible explanations for this. Studies suggest dream recall may be linked to patterns of activity in the brain. Our ability to recall our dreams may be influenced by interpersonal attachment styles—the way we tend to form bonds with other people in our lives.

Changing hormone levels throughout the night might also have a role in our ability to recall our dreams. During REM sleep—a time of active dreaming—levels of the hormone cortisol are high, and may interfere with communication between areas of the brain that are involved in memory consolidation. Our most active dreaming occurs during REM sleep.

Adults spend roughly 25 percent of their sleep time in REM sleep, with longer periods of REM sleep occurring later in the night and in the early morning. REM sleep is one part of the normal sleep cycle. In addition to REM sleep, sleep cycles contain three other stages of sleep. Dreaming can occur in every stage of sleep. Dreams during REM sleep appear to be more visually vivid, bizarre, and narratively-driven than dreams during other sleep stages.

Have you ever woken and not been able to move or speak? This scary sleep phenomenon is indirectly related to dreaming. During REM sleep, the body goes into a state of temporary paralysis, a condition known as REM atonia. This appears to be the body’s way of protecting itself during dreaming. REM atonia keeps us from acting out physically in response to dreams.

Think of some of the scary or exciting dreams you’ve experienced. Maybe you’ve been flying over a mountain range, or been chased by a masked intruder. Imagine if you could respond physically to these dream experiences? You might fly yourself right out of bed onto the floor.

It’s possible to awaken and still be in a state of sleep paralysis. This can be a really scary experience, particularly the first time it happens. Waking in sleep paralysis is a sign that your body may not be making smooth transitions between the stages of sleep. This can be the result of stress, sleep deprivation, other sleep disorders including narcolepsy, as well as a side effect of medications or over-consumption of drugs or alcohol. 

Are there different kinds of dreams? 

Not all dreaming is the same. Dreaming runs the gamut of human experience. Our dreams encompass a dizzying range of emotions and events—and sometimes they’re just downright bizarre. Dreams can be funny, frightening, sad and strange. Flying dreams can be euphoric, chasing dreams can be terrifying, forgot-to-study-for-my-exam dreams can be stressful. There are several different types of dreams, including recurring dreams, wet dreams, and lucid dreams. (Nightmares are their own special kind of dream, which I’ll talk about in a separate article.) Let’s look at some distinct forms of dreaming.

Recurring dreams are dreams that re-appear over and over again. Recurring dreams may contain more threatening and disturbing content than regular dreams. Research suggests there are links between recurring dreams and psychological distress in both adults and children.

Wet dreams are also called nocturnal emissions. These dreams involve ejaculation during sleep, usually accompanied by a sexual dream. Wet dreams happen to boys during puberty, when testosterone starts to be produced in the body. Not all boys have wet dreams, but many do, and they are a normal part of healthy development.

Lucid dreams are an especially fascinating form of dream. In lucid dreams, the dreamer is aware of the fact that he or she is dreaming. Lucid dreamers often can even manipulate or control their dream as it unfolds. It seems that lucid dreaming is related to unusually elevated levels of brain activity. Lucid dreamers have shown significantly higher brain wave frequencies than non-lucid dreamers, as well as increased activity in parts of the frontal lobe of the brain. This area of the brain is deeply involved with our conscious awareness, a sense of self, as well as language and memory. Research into lucid dreams are not only shedding light on the mechanics of dreaming, but also teaching us about the brain and about consciousness itself.

What are the most common dreams? 

Examining and interpreting the content of dreams has fascinated people since ancient times. In ancient cultures, dream interpreters were sought-after and revered experts. Most of what we know today about dream content has been gathered using dream reports and questionnaires.

Dream experiences vary widely, but there are well-established themes that occur among many dreamers across ages and cultures. Some of the most common dream subjects include:

  • School dreams: studying, taking tests
  • Being chased
  • Sexual dreams
  • Falling
  • Being late
  • Flying
  • Being attacked physically
  • Dreaming of someone dead being alive, or someone alive being dead

New brain-imaging technology is allowing scientists to peek into dreaming minds like never before. Scientists are now analyzing brain activity during sleep to de-code the content of dreams. A group of scientists in Japan have been able to predict dream content using MRI imaging with 70 percent accuracy. Scientists at University of Wisconsin-Madison recently found that the areas of the brain used to perform tasks in our waking lives are also used for those tasks in dreams. One example: if a dream involves movement, the area of the brain used for movement perception becomes more active.

How much of dreaming comes from my daily life?

Our waking lives seem to have an enormous influence over our dreams. In dreams, a significant percentage of the people who appear in dreams are known to the dreamer. One study found more than 48 percent of dream characters were recognizable by name to dreamers. Another 35 percent of characters were identifiable to dreamers by their generic social role or relationship—as a friend, or a doctor or police officer, for example. Fewer than one fifth of dream characters—16 percent–were unrecognizable to dreamers.

A lot of our dreams contain content that’s related to autobiographical memories—memories about the self. Pregnant women dream more about pregnancy and childbirth. Hospice workers who act as caregivers to others dream about the experiences of care-giving and the people for whom they care. Musicians dream twice as often about music as non-musicians do.

There’s also some fascinating research that shows our capacity to dream beyond our waking experiences, in profound ways. Dream reports of people born paralyzed reveal that they walk, swim, and run in their dreams as often as people without paralysis. Dream reports of people born deaf indicate they often hear in their dreams.

Daily life experiences don’t always present themselves in dreams immediately. Sometimes an experience from life will filter through to a dream after several days, or even a week. This delay is what’s known as dream lag.

Scientists studying the relationship of memory to dreams have identified different types of memory that can be incorporated into dreams. Both very short-term memories (known as day-residue), and slightly longer-term memories (from a period of about a week), often present themselves in dreams. Dreaming of these events may actually be an important part of the memory consolidation process. The incorporation of memories into dreams isn’t necessarily seamless or even realistic. Rather, memories from waking life often appear in dreams in incomplete pieces, like shards of glass from a broken mirror. As much as dreams may contain aspects of everyday, routine life, dreaming is also a state in which we can contend with extraordinary and difficult experiences.

Another possible function of dreaming is the processing and coming to terms with traumatic events. Grief, fear, loss, abandonment, even physical pain, are all emotions and experiences that often replay themselves in dreams. Studies of people who’ve experienced loss of loved ones indicate that most of them dream about the deceased. Grieving people report several similar themes to these dreams, including:

  • Recalling past experiences when loved ones were alive
  • Seeing loved ones happy and at peace
  • Receiving messages from loved ones

The same study found that 60 percent of bereaved dreamers said their dreams exerted influence over their grieving process.

Can dreaming give me a performance boost? 

Dreams may help us solve problems and be creative. One study of musicians’ dreams found that not only did they dream frequently of music, but nearly half of the music they recalled from their dreams was unfamiliar and novel to them, suggesting that composing is possible in dreams. Paul McCartney famously credited the composition of The Beatles song “Yesterday” to a dream. Other artists, from the poet William Blake to the filmmaker Ingmar Bergman, have claimed to rely on dreams for creative inspiration and guidance. The golfer Jack Nicklaus solved a nagging problem with his golf swing after sorting out the problem in a dream.

Dreaming can help with at least some types of problem solving. Lucid dreamers can use their dreams effectively to solve creative problems, according to research. Dreams seem to be fertile territory for influencing and enhancing our waking frame of mind. Dreams can provide us with insight to what is preoccupying our minds and our hearts. Often healing, often mysterious, always fascinating, dreams can both shape us and show us who we are.