Every night, as we drift off to sleep, our brains begin producing one of the most fascinating experiences known to science: dreams.
Most of us spend nearly a third of our lives asleep, and much of that time is accompanied by dreams. Yet despite decades of research, scientists still do not fully understand why we dream or exactly what purpose dreams serve.
One thing is certain: virtually everyone dreams, whether they remember it or not.
What Are Dreams?
Dreams are sequences of images, thoughts, emotions, sensations, and stories that occur while we sleep. Some are realistic and mundane. Others are bizarre enough to make no sense at all.
A dream might place you back in your childhood home, reunite you with someone who died years ago, or have you taking a math test while riding a giraffe through a shopping mall. Strangely, while we’re dreaming, even the most absurd situations often seem perfectly normal.
Researchers believe dreaming occurs during several stages of sleep, but the most vivid dreams usually happen during REM sleep, short for Rapid Eye Movement. During REM sleep, brain activity becomes surprisingly similar to what occurs while we are awake.
Why Do We Dream?
Scientists have proposed several theories.
One leading idea is that dreams help process memories. Throughout the day, our brains absorb enormous amounts of information. During sleep, the brain may sort through those experiences, deciding which memories to keep and which can be discarded.
Another theory suggests dreams help us process emotions. Brain regions associated with fear, anxiety, happiness, and social interaction are highly active during dreaming. Some researchers believe dreams allow us to mentally rehearse situations and work through emotional challenges in a safe environment.
There is also evidence that dreaming may contribute to creativity and problem-solving. People sometimes report waking with solutions to problems that had stumped them the day before.
Famous Dreams That Changed History
Several notable discoveries and works of art have been linked to dreams.
Chemist August Kekulé claimed that the structure of the benzene molecule came to him after dreaming of a snake biting its own tail.
Author Mary Shelley said the idea for Frankenstein emerged from a vivid dream.
Even musician Paul McCartney has stated that the melody for the Beatles song “Yesterday” first came to him while sleeping.
Whether dreams actually create ideas or simply help us connect thoughts in new ways remains a matter of debate.
Why Are Dreams So Weird?
One reason dreams often seem illogical is that the parts of the brain responsible for critical thinking and reality-checking are less active during sleep.
Meanwhile, emotional and visual centers remain highly active.
The result is a world where impossible events feel completely believable.
Your brain may casually combine your third-grade teacher, your grandmother, your current grocery store, and a vacation you took twenty years ago into a single scene and never bother explaining why.
Why Do We Forget Most Dreams?
Many people can remember a dream vividly for a few moments after waking, only to forget it completely minutes later.
Scientists believe this occurs because the brain systems involved in storing long-term memories are less active during dreaming than during waking life.
Studies suggest most dreams are forgotten within five to ten minutes after waking unless they are deliberately recalled or written down.
Keeping a dream journal is one of the best ways to improve dream memory.
Lucid Dreaming: Knowing You’re Dreaming
One of the strangest dream experiences is lucid dreaming.
In a lucid dream, the dreamer becomes aware that they are asleep and dreaming. Some people can even influence what happens next.
Experienced lucid dreamers report being able to fly, visit imagined locations, or deliberately alter the dream’s storyline.
Researchers have confirmed that lucid dreaming is a genuine phenomenon, although it remains relatively uncommon.
Nightmares and Night Terrors
Most people occasionally experience nightmares, especially during periods of stress.
Nightmares are frightening dreams that usually occur during REM sleep and are often remembered afterward.
Night terrors are different. They usually occur in children, happen during deeper stages of sleep, and often involve screaming or intense fear. Unlike nightmares, people experiencing night terrors frequently remember little or nothing about the episode afterward.
Do Animals Dream?
Scientists believe many animals dream.
Anyone who has watched a sleeping dog twitch its legs, bark softly, or appear to chase something while asleep has probably wondered what is happening.
Studies have shown that many mammals experience REM sleep similar to humans. Researchers generally believe that dogs, cats, and numerous other animals likely dream, although we can never know exactly what those dreams contain.
The Most Common Dream Themes
People around the world report surprisingly similar dream experiences.
Among the most common are:
- Falling
- Being chased
- Losing teeth
- Arriving late
- Being unprepared for an exam
- Flying
- Finding hidden rooms in a house
- Meeting deceased relatives
Scientists believe these recurring themes may reflect common human anxieties, hopes, and experiences.
The Mystery Continues
Despite tremendous advances in sleep science, dreams remain one of the least understood aspects of human consciousness.
They may help us process memories. They may help regulate emotions. They may stimulate creativity. Most likely, they do several things at once.
What we do know is that every night billions of people enter a world created entirely by their own minds—a place where the ordinary becomes extraordinary, the impossible becomes routine, and where a talking squirrel somehow never seems out of place.
Sweet dreams.