Dreams are successions of images, ideas, emotions, and sensations that occur involuntarily in the mind during certain stages of sleep.[1] The content and purpose of dreams are not definitively understood, though they have been a topic of scientific speculation, as well as a subject of philosophical and religious interest, throughout recorded history. The scientific study of dreams is called oneirology.[2]
Dreams mainly occur in the rapid-eye movement (REM) stage of sleep—when brain activity is high and resembles that of being awake. REM sleep is revealed by continuous movements of the eyes during sleep. At times, dreams may occur during other stages of sleep. However, these dreams tend to be much less vivid or memorable.[3]
The length of a dream can vary; they may last for a few seconds, or approximately 20–30 minutes.[3] People are more likely to remember the dream if they are awakened during the REM phase. The average person has three to five dreams per night, but some may have up to seven dreams in one night.[4] The dreams tend to last longer as the night progresses. During a full eight-hour night sleep, most dreams occur in the typical two hours of REM.[5]
In modern times, dreams have been seen as a connection to the unconscious mind. They range from normal and ordinary to overly surreal and bizarre. Dreams can have varying natures, such as frightening, exciting, magical, melancholic, adventurous, or sexual. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming, where the dreamer is self-aware. Dreams can at times make a creative thought occur to the person or give a sense of inspiration.[6]
Opinions about the meaning of dreams have varied and shifted through time and culture. The earliest recorded dreams were acquired from materials dating back approximately 5000 years, in Mesopotamia, where they were documented on clay tablets. In the Greek and Roman periods, the people believed that dreams were direct messages from one and/or multiple deities, from deceased persons, and that they predicted the future. Some cultures practiced dream incubation with the intention of cultivating dreams that are of prophecy.[7]
Sigmund Freud, who developed the discipline of psychoanalysis, wrote extensively about dream theories and their interpretations in the early 1900s.[8] He explained dreams as manifestations of our deepest desires and anxieties, often relating to repressed childhood memories or obsessions. In The Interpretation of Dreams (1899), Freud developed a psychological technique to interpret dreams and devised a series of guidelines to understand the symbols and motifs that appear in our dreams.

Cultural meaning
Main article: Dream interpretation
Ancient history
The Dreaming is an common term within the animist creation narrative of indigenous Australians for a personal, or group, creation and for what may be understood as the "timeless time" of formative creation and perpetual creating.[9]
The Sumerians in Mesopotamia left evidence of dreams dating back to 3100 BC. According to these early recorded stories, gods and kings, like the 7th century BC scholar-king Assurbanipal, paid close attention to dreams. In his archive of clay tablets, some amounts of the story of the legendary king Gilgamesh were found.[10]
The Mesopotamians believed that the soul, or some part of it, moves out from the body of the sleeping person and actually visits the places and persons the dreamer sees in their sleep. Sometimes the god of dreams is said to carry the dreamer.[11] Babylonians and Assyrians divided dreams into "good," which were sent by the gods, and "bad," sent by demons - They also believed that their dreams were omens and prophecies.[12]
In ancient Egypt, as far back as 2000 BC, the Egyptians wrote down their dreams on papyrus. People with vivid and significant dreams were thought blessed and were considered special.[13] Ancient Egyptians believed that dreams were like oracles, bringing messages from the gods. They thought that the best way to receive divine revelation was through dreaming and thus they would induce (or "incubate") dreams. Egyptians would go to sanctuaries and sleep on special "dream beds" in hope of receiving advice, comfort, or healing from the gods.[14]

Classical history
In Chinese history, people wrote of two vital aspects of the soul of which one is freed from the body during slumber to journey a dream realm, while the other remained in the body,[15] although this belief and dream interpretation had been questioned since early times, such as by the philosopher Wang Chong (27-97).[15] The Indian text Upanishads, written between 900 and 500 BC, emphasize two meanings on dreams. The first says that dreams are merely expressions of inner desires. The second is the belief of the soul leaving the body and being guided until awakened.
The Greeks shared their beliefs with the Egyptians on how to interpret good and bad dreams, and the idea of incubating dreams. Morpheus, the Greek god of dreams also sent warnings and prophecies to those who slept at shrines and temples. The earliest Greek beliefs of dreams were that their gods physically visited the dreamers, where they entered through a keyhole, and exiting the same way after the divine message was given.
Antiphon wrote the first known Greek book on dreams in the 5th century BC. In that century, other cultures influenced Greeks to develop the belief that souls left the sleeping body.[16] Hippocrates (469-399 BC) had a simple dream theory: during the day, the soul receives images; during the night, it produces images. Greek philosopher Aristotle (384-322 BC) believed dreams caused physiological activity. He thought dreams could analyze illness and predict diseases. Marcus Tullius Cicero, for his part, believed that all dreams are produced by thoughts and conversations a dreamer had during the preceding days.[17] Cicero's Somnium Scipionis described a lengthy dream vision, which in turn was commented on by Macrobius in his Commentarii in Somnium Scipionis.
In Abrahamic religions
In Judaism, dreams are considered part of the experience of the world that can be interpreted and from which lessons can be garnered. It is discussed in the Talmud, Tractate Berachot 55-60.
The ancient Hebrews connected their dreams heavily with their religion, though the Hebrews were monotheistic and believed that dreams were the voice of one god alone. Hebrews also differentiated between good dreams (from God) and bad dreams (from evil spirits). The Hebrews, like many other ancient cultures, incubated dreams in order to receive divine revelation. For example, the Hebrew prophet Samuel, would "lie down and sleep in the temple at Shiloh before the Ark and receive the word of the Lord." Most of the dreams in the Bible are in the Book of Genesis.[18]
Christians mostly shared their beliefs with the Hebrews and thought that dreams were of the supernatural element because the Old Testament had frequent stories of dreams with divine inspiration. The most famous of these dream stories was Jacob's dream of a ladder that stretched from Earth to Heaven. Many Christians preach that God can speak to his people through their dreams.
Iain R. Edgar has researched the role of dreams in Islam.[19] He has argued that dreams play an important role in the history of Islam and the lives of Muslims. Dream interpretation, is the only way that Muslims can receive revelations from God after the death of the last Prophet Mohammed.[20]

Dreams and philosophical realism
Main article: Dream argument
Some philosophers have concluded that what we think of as the "real world" could be or is an illusion (an idea known as the skeptical hypothesis about ontology).
The first recorded mention of the idea was by Zhuangzi, and it is also discussed in Hinduism, which makes extensive use of the argument in its writings.[21] It was formally introduced to Western philosophy by Descartes in the 17th century in his Meditations on First Philosophy. Stimulus, usually an auditory one, becomes a part of a dream, eventually then awakening the dreamer.

Postclassical and medieval history
Some Indigenous American tribes and Mexican civilizations believe that dreams are a way of visiting and having contact with their ancestors.[22] Some Native American tribes used vision quests as a rite of passage, fasting and praying until an anticipated guiding dream was received, to be shared with the rest of the tribe upon their return.[23][24]
The Middle Ages brought a harsh interpretation of dreams. They were seen as evil, and the images as temptations from the devil. Many believed that during sleep, the devil could fill the human mind with corrupting and harmful thoughts. Martin Luther, founder of Protestantism, believed dreams were the work of the Devil. However, Catholics such as St. Augustine and St. Jerome claimed that the direction of their life were heavily influenced by their dreams.
In art
Dreams and dark imaginings are the theme of Goya's etching The Sleep of Reason Produces Monsters. There is a painting by Salvador Dalí that depicts this concept, titled Dream Caused by the Flight of a Bee around a Pomegranate a Second Before Awakening (1944). Henri Rousseau's last painting was The Dream. Le Rêve ("The Dream") is a 1932 painting by Pablo Picasso.
In literature
Dream frames were frequently used in medieval allegory to justify the narrative; The Book of the Duchess[25] and The Vision Concerning Piers Plowman[26] are two such dream visions. Even before them, in antiquity, the same device had been used by Cicero and Lucian of Samosata.
They have also featured in fantasy and speculative fiction since the 19th century. One of the best-known dream worlds is Wonderland from Lewis Carroll's Alice's Adventures in Wonderland, as well as Looking-Glass Land from its sequel, Through the Looking-Glass. Unlike many dream worlds, Carroll's logic is like that of actual dreams, with transitions and flexible causality.
Other fictional dream worlds include the Dreamlands of H. P. Lovecraft's Dream Cycle[27] and The Neverending Story's[28] world of Fantasia, which includes places like the Desert of Lost Dreams, the Sea of Possibilities and the Swamps of Sadness. Dreamworlds, shared hallucinations and other alternate realities feature in a number of works by Phillip K. Dick, such as The Three Stigmata of Palmer Eldritch and Ubik. Similar themes were explored by Jorge Luis Borges, for instance in The Circular Ruins.
In popular culture
Modern popular culture often conceives of dreams, like Freud, as expressions of the dreamer's deepest fears and desires.[29] In films such as Spellbound (1945), The Manchurian Candidate (1962), Field of Dreams (1989), and Inception (2010), the protagonists must extract vital clues from surreal dreams.[30]
Most dreams in popular culture are, however, not symbolic, but straightforward and realistic depictions of their dreamer's fears and desires.[30] Dream scenes may be indistinguishable from those set in the dreamer's real world, a narrative device that undermines the dreamer's and the audience's sense of security[30] and allows horror film protagonists, such as those of Carrie (1976), Friday the 13th (1980) or An American Werewolf in London (1981) to be suddenly attacked by dark forces while resting in seemingly safe places.[30]
In speculative fiction, the line between dreams and reality may be blurred even more in the service of the story.[30] Dreams may be psychically invaded or manipulated (Dreamscape, 1984; the Nightmare on Elm Street films, 1984–2010; Inception, 2010) or even come literally true (as in The Lathe of Heaven, 1971). In Ursula K. Le Guin's book, The Lathe of Heaven (1971), the protagonist finds that his "effective" dreams can retroactively change reality. Peter Weir's 1977 Australian film The Last Wave makes a simple and straightforward postulate about the premonitory nature of dreams (from one of his Aboriginal characters) that "... dreams are the shadow of something real". Such stories play to audiences' experiences with their own dreams, which feel as real to them.[30]
Dynamic psychiatry
Freudian view of dreams
In the late 19th century, psychotherapist Sigmund Freud developed a theory that the content of dreams is driven by unconscious wish fulfillment. Freud called dreams the "royal road to the unconscious."[31] He theorized that the content of dreams reflects the dreamer's unconscious mind and specifically that dream content is shaped by unconscious wish fulfillment. He argued that important unconscious desires often relate to early childhood memories and experiences. Freud's theory describes dreams as having both manifest and latent content. Latent content relates to deep unconscious wishes or fantasies while manifest content is superficial and meaningless. Manifest content often masks or obscures latent content.
In his early work, Freud argued that the vast majority of latent dream content is sexual in nature, but he later moved away from this categorical position. In Beyond the Pleasure Principle he considered how trauma or aggression could influence dream content. He also discussed supernatural origins in Dreams and Occultism, a lecture published in New Introductory Lectures on Psychoanalysis.[32]
Jungian and other views of dreams
Carl Jung rejected many of Freud's theories. Jung expanded on Freud's idea that dream content relates to the dreamer's unconscious desires. He described dreams as messages to the dreamer and argued that dreamers should pay attention for their own good. He came to believe that dreams present the dreamer with revelations that can uncover and help to resolve emotional or religious problems and fears.[33]
Jung wrote that recurring dreams show up repeatedly to demand attention, suggesting that the dreamer is neglecting an issue related to the dream. He believed that many of the symbols or images from these dreams return with each dream. Jung believed that memories formed throughout the day also play a role in dreaming. These memories leave impressions for the unconscious to deal with when the ego is at rest. The unconscious mind re-enacts these glimpses of the past in the form of a dream. Jung called this a day residue.[34] Jung also argued that dreaming is not a purely individual concern, that all dreams are part of "one great web of psychological factors."
Fritz Perls presented his theory of dreams as part of the holistic nature of Gestalt therapy. Dreams are seen as projections of parts of the self that have been ignored, rejected, or suppressed.[35] Jung argued that one could consider every person in the dream to represent an aspect of the dreamer, which he called the subjective approach to dreams. Perls expanded this point of view to say that even inanimate objects in the dream may represent aspects of the dreamer. The dreamer may, therefore, be asked to imagine being an object in the dream and to describe it, in order to bring into awareness the characteristics of the object that correspond with the dreamer's personality.
Psychological theories of dreams
Dreams for testing and selecting mental schemas
Coutts[62] describes dreams as playing a central role in a two-phase sleep process that improves the mind's ability to meet human needs during wakefulness. During the accommodation phase, mental schemas self-modify by incorporating dream themes. During the emotional selection phase, dreams test prior schema accommodations. Those that appear adaptive are retained, while those that appear maladaptive are culled. The cycle maps to the sleep cycle, repeating several times during a typical night's sleep. Alfred Adler suggested that dreams are often emotional preparations for solving problems, intoxicating an individual away from common sense toward private logic. The residual dream feelings may either reinforce or inhibit contemplated action.
Evolutionary psychology theories of dreams
Numerous theories state that dreaming is a random by-product of REM sleep physiology and that it does not serve any natural purpose.[63] Flanagan claims that "dreams are evolutionary epiphenomena" and they have no adaptive function. "Dreaming came along as a free ride on a system designed to think and to sleep.[64] " Hobson, for different reasons, also considers dreams epiphenomena. He believes that the substance of dreams have no significant influence on waking actions, and most people go about their daily lives perfectly well without remembering their dreams.[65]
Hobson proposed the activation-synthesis theory, which states that "there is a randomness of dream imagery and the randomness synthesizes dream-generated images to fit the patterns of internally generated stimulations".[66] This theory is based on the physiology of REM sleep, and Hobson believes dreams are the outcome of the forebrain reacting to random activity beginning at the brainstem. The activation-synthesis theory hypothesizes that the peculiar nature of dreams is attributed to certain parts of the brain trying to piece together a story out of what is essentially bizarre information.[67]
However, evolutionary psychologists believe dreams serve some adaptive function for survival. Deirdre Barrett describes dreaming as simply "thinking in different biochemical state" and believes people continue to work on all the same problems—personal and objective—in that state.[68] Her research finds that anything—math, musical composition, business dilemmas—may get solved during dreaming.[69][70] In a related theory, which Mark Blechner terms "Oneiric Darwinism," dreams are seen as creating new ideas through the generation of random thought mutations. Some of these may be rejected by the mind as useless, while others may be seen as valuable and retained.[71]
Finnish psychologist Antti Revonsuo posits that dreams have evolved for "threat simulation" exclusively. According to the Threat Simulation Theory he proposes, during much of human evolution physical and interpersonal threats were serious, giving reproductive advantage to those who survived them. Therefore dreaming evolved to replicate these threats and continually practice dealing with them. In support of this theory, Revonsuo shows that contemporary dreams comprise much more threatening events than people meet in daily non-dream life, and the dreamer usually engages appropriately with them.[72] It is suggested by this theory that dreams serve the purpose of allowing for the rehearsal of threatening scenarios in order to better prepare an individual for real-life threats.
According to Tsoukalas (2012) the biology of dreaming is related to the reactive patterns elicited by predatorial encounters (especially the tonic immobility reflex), a fact that lends support to evolutionary theories claiming that dreams specialize in threat avoidance and/or emotional processing.[50]
Psychosomatic theory of dreams
Y.D. Tsai developed in 1995 a 3-hypothesis theory[73] that is claimed to provide a mechanism for mind-body interaction and explain many dream-related phenomena, including hypnosis, meridians in Chinese medicine, the increase in heart rate and breathing rate during REM sleep, that babies have longer REM sleep, lucid dreams, etc.
Dreams are a product of "dissociated imagination," which is dissociated from the conscious self and draws material from sensory memory for simulation, with feedback resulting in hallucination. By simulating the sensory signals to drive the autonomous nerves, dreams can affect mind-body interaction. In the brain and spine, the autonomous "repair nerves," which can expand the blood vessels, connect with compression and pain nerves. Repair nerves are grouped into many chains called meridians in Chinese medicine. When some repair nerves are prodded by compression or pain to send out their repair signals, a chain reaction spreads out to set other repair nerves in the same meridian into action. While dreaming, the body also employs the meridians to repair the body and help it grow and develop by simulating very intensive movement-compression signals to expand the blood vessels when the level of growth enzymes increase.

Other hypotheses on dreaming
There are many other hypotheses about the function of dreams, including:[74] * Dreams allow the repressed parts of the mind to be satisfied through fantasy while keeping the conscious mind from thoughts that would suddenly cause one to awaken from shock.[75] * Ferenczi[76] proposed that the dream, when told, may communicate something that is not being said outright. * Dreams regulate mood.[77] * Hartmann[78] says dreams may function like psychotherapy, by "making connections in a safe place" and allowing the dreamer to integrate thoughts that may be dissociated during waking life. * LaBerge and DeGracia[79] have suggested that dreams may function, in part, to recombine unconscious elements within consciousness on a temporary basis by a process they termm “mental recombination”, in analogy with genetic recombination of DNA. From a bio-computational viewpoint, mental recombination may contribute to maintaining an optimal information processing flexibility in brain information networks.
Apparent precognition of real events
Main article: Precognition
According to surveys, it is common for people to feel their dreams are predicting subsequent life events.[91] Psychologists have explained these experiences in terms of memory biases, namely a selective memory for accurate predictions and distorted memory so that dreams are retrospectively fitted onto life experiences.[91] The multi-faceted nature of dreams makes it easy to find connections between dream content and real events.[92]
In one experiment, subjects were asked to write down their dreams in a diary. This prevented the selective memory effect, and the dreams no longer seemed accurate about the future.[93] Another experiment gave subjects a fake diary of a student with apparently precognitive dreams. This diary described events from the person's life, as well as some predictive dreams and some non-predictive dreams. When subjects were asked to recall the dreams they had read, they remembered more of the successful predictions than unsuccessful ones.[94]
Lucid dreaming
Main article: Lucid dreaming
Lucid dreaming is the conscious perception of one's state while dreaming. In this state the dreamer may often (but not always) have some degree of control over their own actions within the dream or even the characters and the environment of the dream. Dream control has been reported to improve with practiced deliberate lucid dreaming, but the ability to control aspects of the dream is not necessary for a dream to qualify as "lucid" — a lucid dream is any dream during which the dreamer knows they are dreaming.[95] The occurrence of lucid dreaming has been scientifically verified.[96]
Oneironaut is a term sometimes used for those who lucidly dream.
Communication through lucid dreaming
In 1975, parapsychologist Keith Hearne successfully communicated to a patient experiencing a lucid dream. On April 12, 1975, after being instructed to move the eyes left and right upon becoming lucid, the subject had a lucid dream and the first recorded signals from a lucid dream were recorded.[97]
Years later, psychophysiologist Stephen LaBerge conducted similar work including: * Using eye signals to map the subjective sense of time in dreams * Comparing the electrical activity of the brain while singing awake and while dreaming. * Studies comparing in-dream sex, arousal, and orgasm[98]
Recalling dreams
The recall of dreams is extremely unreliable, though it is a skill that can be trained. Dreams can usually be recalled if a person is awakened while dreaming.[88] Women tend to have more frequent dream recall than men.[88] Dreams that are difficult to recall may be characterized by relatively little affect, and factors such as salience, arousal, and interference play a role in dream recall. Often, a dream may be recalled upon viewing or hearing a random trigger or stimulus. The salience hypothesis proposes that dream content that is salient, that is, novel, intense, or unusual, is more easily remembered. There is considerable evidence that vivid, intense, or unusual dream content is more frequently recalled.[100] A dream journal can be used to assist dream recall, for personal interest or psychotherapy purposes.
For some people, sensations from the previous night's dreams are sometimes spontaneously experienced in falling asleep. However they are usually too slight and fleeting to allow dream recall. At least 95% of all dreams are not remembered. Certain brain chemicals necessary for converting short-term memories into long-term ones are suppressed during REM sleep. Unless a dream is particularly vivid and if one wakes during or immediately after it, the content of the dream is not remembered.[101]
Individual differences
In line with the salience hypothesis, there is considerable evidence that people who have more vivid, intense or unusual dreams show better recall. There is evidence that continuity of consciousness is related to recall. Specifically, people who have vivid and unusual experiences during the day tend to have more memorable dream content and hence better dream recall. People who score high on measures of personality traits associated with creativity, imagination, and fantasy, such as openness to experience, daydreaming, fantasy proneness, absorption, and hypnotic susceptibility, tend to show more frequent dream recall.[100] There is also evidence for continuity between the bizarre aspects of dreaming and waking experience. That is, people who report more bizarre experiences during the day, such as people high in schizotypy (psychosis proneness) have more frequent dream recall and also report more frequent nightmares.[100]
Déjà vu
Main article: Déjà vu
One theory of déjà vu attributes the feeling of having previously seen or experienced something to having dreamt about a similar situation or place, and forgetting about it until one seems to be mysteriously reminded of the situation or the place while awake.[102]
Daydreaming
A daydream is a visionary fantasy, especially one of happy, pleasant thoughts, hopes or ambitions, imagined as coming to pass, and experienced while awake.[103] There are many different types of daydreams, and there is no consistent definition amongst psychologists.[103] The general public also uses the term for a broad variety of experiences. Research by Harvard psychologist Deirdre Barrett has found that people who experience vivid dream-like mental images reserve the word for these, whereas many other people refer to milder imagery, realistic future planning, review of past memories or just "spacing out"—i.e. one's mind going relatively blank—when they talk about "daydreaming."[104]
While daydreaming has long been derided as a lazy, non-productive pastime, it is now commonly acknowledged that daydreaming can be constructive in some contexts.[105] There are numerous examples of people in creative or artistic careers, such as composers, novelists and filmmakers, developing new ideas through daydreaming. Similarly, research scientists, mathematicians and physicists have developed new ideas by daydreaming about their subject areas.
Hallucination
A hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are perceptions in a conscious and awake state, in the absence of external stimuli, and have qualities of real perception, in that they are vivid, substantial, and located in external objective space. The latter definition distinguishes hallucinations from the related phenomena of dreaming, which does not involve wakefulness.
Nightmares
A nightmare is an unpleasant dream that can cause a strong negative emotional response from the mind, typically fear and/or horror, but also despair, anxiety and great sadness. The dream may contain situations of danger, discomfort, psychological or physical terror. Sufferers usually awaken in a state of distress and may be unable to return to sleep for a prolonged period of time.[106]
Night terrors
A night terror, also known as a sleep terror or pavor nocturnus, is a parasomnia disorder that predominantly affects children, causing feelings of terror or dread. Night terrors should not be confused with nightmares, which are bad dreams that cause the feeling of horror or fear.
Possible explanations for why we dream include: * To represent unconscious desires and wishes * To interpret random signals from the brain and body during sleep * To consolidate and process information gathered during the day * To work as a form of psychotherapy
10 Facts About Dreams
What Researchers Have Discovered About Dreams
1. Everybody Dreams
Men do it. Women do it. Even babies do it. We all dream, even those of us who claim not to. In fact, researchers have found that people usually have several dreams each night, each one lasting for between 5 to 20 minutes. During a typical lifetime, people spend an average of six years dreaming!

2. But You Forget Most of Your Dreams
According to estimates by dream researcher J. Allan Hobson, as much as 95 percent of all dreams are quickly forgotten shortly after waking. Why are our dreams so difficult to remember? According to one theory, the changes in the brain that occur during sleep do not support the information processing and storage needed for memory formation to take place. Brain scans of sleeping individuals have shown that the frontal lobes, the area that plays a key role in memory formation, are inactive during REM sleep, the stage in which dreaming occurs.
3. Not All Dreams Are In Color

While approximately 80 percent of all dreams are in color, there are a small percentage of people who claim to only dream in black and white. In studies where dreamers have been awakened and asked to select colors from a chart that match those in their dreams, soft pastel colors are those most frequently chosen.

4. Men and Women Dream Differently
Researchers have found a number of differences between men and women when it comes to the content of their dreams. In one study, men reported more instances of dreaming about aggression than women did. According to dream researcher William Domhoff, women tend to have slightly longer dreams that feature more characters. When it comes to the characters that typically appear in dreams, men dream about other men twice as often as they do about women, while women tend to dream about both sexes equally.
5. Animals Probably Dream
Have you ever watched a sleeping dog wag its tail or move its legs while asleep? While it's hard to say for sure whether the animal is truly dreaming, researchers believe that it is likely that animals do indeed dream. Just like humans, animals go through sleep stages that include cycles of REM and NREM sleep. In one study, a gorilla was taught sign language as a means of communication. At one point, the gorilla signed "sleep pictures," possibly indicating the experience of dreaming.

6. You Can Control Your Dreams
A lucid dream is one in which you are aware that you are dreaming even though you are still asleep. During this type of dream, you can often "direct" or control the content of the dream. Approximately half of all people can remember experiencing at least one instance of lucid dreaming, and some individuals are able to have lucid dreams quite frequently.

7. Negative Emotions Are More Common in Dreams
Over a period of more than forty years, researcher Calvin S. Hall collected more than 50,000 dream accounts from college students. These reports were made available to the public during the 1990s by Hall's student William Domhoff. The dream accounts revealed that many emotions are experienced during dreams including joy, happiness and fear. The most common emotion experienced in dreams was anxiety, and negative emotions in general were much more common than positive ones.

8. Blind People Dream
While people who lost their eyesight prior to age five usually do not have visual dreams in adulthood, they still dream. Despite the lack of visuals, the dreams of the blind are just as complex and vivid as those of the sighted. Instead of visual sensations, blind individuals' dreams typically include information from the other senses such as sound, touch, taste, hearing and smell.

9. You Are Paralyzed During Your Dreams
REM sleep, the stage of sleep during which dreaming occurs, is characterized by paralysis of the voluntary muscles. Why? The phenomenon is known as REM atonia and prevents you from acting out your dreams while you're asleep. Basically, because motor neurons are not stimulated, your body does not move.
In some cases, this paralysis can even carry over into the waking state for as long as ten minutes, a condition known as sleep paralysis. Have you ever woken up from a terrifying dream only to find yourself unable to move? While the experience can be frightening, experts advise that it is perfectly normal and should last only a few minutes before normal muscle control returns.
10. Many Dreams Are Universal

While dreams are often heavily influenced by our personal experiences, researchers have found that certain themes are very common across different cultures. For example, people from all over the world frequently dream about being chased, being attacked or falling. Other common dream experiences include school events, feeling frozen and unable to move, arriving late, flying and being naked in public.

Dreams can be mysterious, but understanding the meaning of our dreams can be downright baffling. The content of our dreams can shift suddenly, feature bizarre elements or frighten us with terrifying imagery. The fact that dreams can be so rich and compelling is what causes many to believe that there must be some meaning to our dreams.

While many theories exist to explain why we dream, no one yet fully understands their purpose, let alone how to interpret the meaning of dreams. In fact, some prominent researchers such as G. William Domhoff suggest that dreams most likely serve no real purpose.
Despite this, dream interpretation has becoming increasingly popular. While research has not demonstrated a purpose for dreams, many experts believe that dreams do have meaning.

According to Domhoff:
"'Meaning' has to do with coherence and with systematic relations to other variables, and in that regard dreams do have meaning. Furthermore, they are very "revealing" of what is on our minds. We have shown that 75 to 100 dreams from a person give us a very good psychological portrait of that individual. Give us 1000 dreams over a couple of decades and we can give you a profile of the person's mind that is almost as individualized and accurate as her or his fingerprints."
Freud: Dreams as the Road to the Unconscious Mind:
In his book The Interpretation of Dreams, Sigmund Freud suggested that the content of dreams is related to wish fulfillment. Freud believed that the manifest content of a dream, or the actually imagery and events of the dream, served to disguise the latent content, or the unconscious wishes of the dreamer.
Freud also described four elements of this process that he referred to as 'dream work': * Condensation – Many different ideas and concepts are represented within the span of a single dream. Information is condensed into a single thought or image.

* Displacement – This element of dream work disguises the emotional meaning of the latent content by confusing the important and insignificant parts of the dream.

* Symbolization – This operation also censors the repressed ideas contained in the dream by including objects that are meant to symbolize the latent content of the dream.

* Secondary Revision – During this final stage of the dreaming process, Freud suggested that the bizarre elements of the dream are reorganized in order to make the dream comprehensible, thus generating the manifest content of the dream.
Jung: Archetypes and the Collective Unconscious:
While Carl Jung shared some commonalities with Freud, he felt that dreams were more than an expression of repressed wishes. Jung suggested that dreams revealed both the personal and collective unconscious and believed that dreams serve to compensate for parts of the psyche that are underdeveloped in waking life. In contradiction to Jung's assertions however, later research by Hall revealed that the traits people exhibit while they awake are the same as those expressed in dreams.
Jung also suggested that archetypes such as the anima, the shadow and the animus are often represented symbolic objects or figures in dreams. These symbols, he believed, represented attitudes that are repressed by the conscious mind. Unlike Freud, who often suggested that specific symbols represent specific unconscious thoughts, Jung believed that dreams can be highly personal and that interpreting these dreams involved knowing a great deal about the individual dreamer.
Hall: Dreams as a Cognitive Process:
Calvin S. Hall proposed that dreams are part of a cognitive process in which dreams serve as ‘conceptions’ of elements of our personal lives. Hall looked for themes and patterns by analyzing thousands of dream diaries from participants, eventually creating a quantitative coding system that divided the content of dreams into a number of different categories.
According to Hall’s theory, interpreting dreams requires knowing: * The actions of the dreamer within the dream * The objects and figures in the dream * The interactions between the dreamer and the characters in the dream * The dream’s setting, transitions, and outcome
The ultimate goal of this dream interpretation is not to understand the dream, however, but to understand the dreamer.
Domhoff: Dreams as a Reflection of Waking Life:
G. William Domhoff is a prominent dream researcher who studied with Calvin Hall at the University of Miami. In large-scale studies on the content of dreams, Domhoff has found that dreams reflect the thoughts and concerns of a dreamer’s waking life. Domhoff suggests a neurocognitive model of dreams in which the process of dreaming results from neurological processes and a system of schemas. Dream content, he suggests, results from these cognitive processes.
Popularizing Dream Interpretation
Since the 1970s, dream interpretation has grown increasingly popular thanks to work by authors such as Ann Faraday. In books such as The Dream Game, Faraday outlined techniques and ideas than anyone can use to interpret their own dreams. Today, consumers can purchase a wide variety of books that offer dream dictionaries, symbol guides and tips for interpreting and understanding dreams.
Dream research will undoubtedly continue to grow and generate interest from people interested in understanding the meaning of their dreams. However, dream expert G. William Domhoff recommends that "...unless you find your dreams fun, intellectually interesting, or artistically inspiring, then feel free to forget your dreams." Others such as Cartwright and Kaszniak propose that dream interpretation may actually reveal more about the interpreter than it does about the meaning of the dream itself.
"A dream is a work of art which requires of the dreamer no particular talent, special training, or technical competence. Dreaming is a creative enterprise in which all may and most do participate." – Clark S. Hall