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Why humans dream remains one of behavioral science's great unanswered questions. Dreams have a purpose but it may not be to send us messages about self-improvement or the future, as many believe. Instead, many researchers now believe that dreaming mediates memory consolidation and mood regulation, a process a little like overnight therapy. But it's not a benefit all share equally: People who are sleep deprived also tend to be dream deprived, spending less time dreaming and perhaps not remembering dreams as well.

What Dreams Mean

Dreams are the stories the brain tells during the REM (rapid eye movement) stage of sleep. People typically have multiple dreams each night that grow longer as sleep draws to a close. Over a lifetime, a person may dream for five or six full years. How best to examine all that content remains a source of debate.

Are all dreams based on real life?

Dreams typically involve elements from waking life, such as known people or familiar locations, but they also often have a fantastical feel. In dreams, people may live out scenarios that would never be possible in real life, although they aren’t always positive.

Can we interpret our dreams?

People have always tried to figure out the meaning of their dreams, but dream interpretation as a field of psychological study emerged in 1899, when Sigmund Freud published The Interpretation of Dreams. Today, most experts disagree with Freud’s conclusions, and some don’t believe dreams signify anything at all. But people continue to mine them for clues to their inner lives, creative insight, and even hints of the future.

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Why We Have Nightmares

Nightmares can create feelings of terror, anxiety, or despair, and lead to psychological distress or sleep problems like insomnia. Research has identified a range of causes for nightmares, including post-traumatic stress, anxiety—especially the presence of generalized anxiety disorder, dissociation, and physiological changes.

Are nightmares based on real-life experiences?

“Re-experiencing” is a common symptom of post-traumatic stress disorder, also known as flashbacks. These involuntary recollections  often manifest in the form of nightmares that can cause significant emotional distress. Even when the dreams are not exact replays of a trauma, they may have a strong symbolic or indirect connection to the event.

Do children have more nightmares than adults?

Terrifying dreams that rouse people from sleep plague children more often than adults, and nightmares can be especially vivid for young children because they may have a harder time separating fantasy from reality. But at least half of grownups also have occasional nightmares, although fewer than 10 percent report frequent or recurring episodes.

Lucid Dreams

During lucid dreaming, which most commonly occurs during late-stage REM sleep, a dreamer is aware that they’re asleep, but is able to control events within their dreams, to some extent. Lucid dreamers report willing themselves to fly, fight, or act out sexual fantasies. There are communities dedicated to learning how to lucid dream at will, although evidence that this is possible remains inconclusive.

How do lucid dreams work?

Research suggests that the brain undergoes a physiological change during lucid dreaming. In fMRI studies, the prefrontal cortex and a cortical network including the frontal, parietal, and temporal zones have been shown to activate when the brain begins lucid dreaming. This appears related to the "waking consciousness” that characterizes lucidity.

Can anyone have lucid dreams?

Most people do not typically experience lucid dreaming, or do not realize they do, and those who do tend to experience it in a limited way, without full agency. But some experts, and advocates of the potential benefits of lucid dreaming for boosting creativity and confidence, and reducing stress, believe most people can train themselves to experience lucid dreams.

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