Why do we dream?
Dreams are stories and images that our minds create while we sleep. They can be entertaining, fun, romantic, disturbing, frightening, and sometimes bizarre.
Why do dreams occur? What causes them? Can we control them? What do they mean?
facts on dreams
Though a few people may not remember dreaming, it is thought that everyone dreams between 3 to 6 times per night.
It is thought that each dream lasts between 5 to 20 minutes.
Around 95% of dreams are forgotten by the time a person gets out of bed.
Dreaming can help you learn and develop long-term memories.
Women dream more about family, children and indoor settings when compared with men.
Recalling something from last week that has appeared in your dream is called the "dream-lag effect."
There is a difference in the quality and quantity of dreams experienced in rapid eye movement and non-rapid eye movement sleep.
48% of people that feature in a dream are recognized by the person dreaming.
Blind people dream more with other sensory components compared with sighted people.
Both sleep and dream quality are affected by alcohol.
Why do we dream?
There are several hypotheses and concepts as to why we dream. Are dreams merely part of the sleep cycle or do they serve some other purpose?
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.
From converging evidence and new research methodologies, researchers have speculated that dreaming:
Is offline memory reprocessing - consolidates learning and memory tasks.
Is a subsystem of the waking default network, which is active during mind wandering and daydreaming. Dreaming could be seen as cognitive simulation of real life experiences.
Participates in the development of cognitive capabilities.
Is psychoanalytic; dreams are highly meaningful reflections of unconscious mental functioning.
Is a unique state of consciousness that incorporates three temporal dimensions: experience of the present, processing of the past, and preparation for the future.
Provides a psychological space where overwhelming, contradictory, or highly complex notions can be brought together by the dreaming ego that would be unsettling while awake. This process serves the need for psychological balance and equilibrium.
As with many things concerning the brain and unconscious thought, there is so much that remains unknown about dreaming. Dreams are difficult to study in a laboratory. As technology and new research techniques are developed, the understanding of dreams will continue to grow.
Phases of sleep
There are five phases of sleep in a sleep cycle:
Stage 1 - light sleep, eyes move slowly, and muscle activity slows. This stage forms 4-5% of total sleep
Stage 2 - eye movement stops and brain waves (fluctuations of electrical activity that can be measured by electrodes) become slower, with occasional bursts of rapid waves called sleep spindles. This stage forms 45-55% of total sleep
Stage 3 - extremely slow brain waves called delta waves begin to appear, interspersed with smaller, faster waves. 4-6% of total sleep
Stage 4 - the brain produces delta waves almost exclusively. It is very difficult to wake someone during stages 3 and 4, which together are called "deep sleep." There is no eye movement or muscle activity. People awakened while in deep sleep do not adjust immediately and often feel groggy and disoriented for several minutes after they wake up. This forms 12-15% of total sleep
Stage 5 - REM - breathing becomes more rapid, irregular and shallow, eyes jerk rapidly in various directions, and limb muscles become temporarily paralyzed. Heart rate increases, blood pressure rises, and males develop penile erections. When people awaken during REM sleep, they often describe bizarre and illogical tales - dreams. Forms 20-25% of total sleep time.
Slow-wave sleep refers to stages 3 and 4 of non-rapid eye movement (NREM) sleep.
What are dreams?
Dreams are a universal human experience that can be described as a state of consciousness characterized by sensory, cognitive and emotional occurrences during sleep. The dreamer has reduced control over the content, visual images and activation of the memory.
There is no cognitive state that has been as extensively studied and yet as misunderstood as much as dreaming.
There are significant differences between the neuroscientific and psychoanalytic approaches to dream analysis. A neuroscientist is interested in the structures involved in dream production and dream organization and narratability. However, psychoanalysis concentrates on the meaning of dreams and on placing them in the context of relationships in the history of the dreamer.
Reports of dreams tend to be full of emotional and vivid experiences that contain themes, concerns, dream figures, objects, etc. that correspond closely to waking life. These elements create a novel "reality" out of seemingly nothing, producing an experience with a lifelike timeframe and lifelike connections.
Neuroscience offers explanations linked to the rapid eye movement (REM) phase of sleep as a pinpoint for where dreaming occurs.
Nightmares are distressing dreams that cause the dreamer to feel a number of disturbing emotions. Common feelings include fear and anxiety.
Nightmares or bad dreams occur in both adults and children and can be caused by:
Use of certain medications or drugs
Lucid dreaming is a state of sleep where the dreamer knows they are dreaming. As a result, the dreamer may have some measure of control over their dream.
The measure of control a dreamer has can vary from lucid dream to lucid dream. They often occur in the middle of a regular dream when the sleeping person realizes suddenly that they are dreaming.
Some people experience lucid dreaming at random while other people are able to increase their capacity to affect how their dreams unfold.
What do dreams mean?
What goes through our minds just before we fall asleep could affect the content of our dreams. For example, during exam time, students may dream about course content; those in relationships may dream of their partner; web developers may see programming code. These circumstantial observations suggest that during the transition from wakefulness to sleep, elements from the everyday re-emerge in dream-like imagery.
Studies have examined the "characters" that appear in dream reports and how they are identified by the dreamer.
A study of 320 adult dream reports found:1
48% of characters represented a named person known to the dreamer
35% of characters were identified by their social role (e.g., policeman) or relationship to dreamer (e.g., a friend)
16% were not recognized.
Among named characters:
32% were identified by appearance
21% identified by behavior
45% by face
44% by "just knowing."
Elements of bizarreness were reported in 14% of named and generic characters.
Another study investigated the relationship between dream emotion and dream character identification. Affection and joy were commonly associated with known characters and were used to identify them even when these emotional attributes were inconsistent with those of the waking state.
The findings suggest that the dorsolateral prefrontal cortex, associated with short-term memory, is less active in the dreaming brain compared to the awake brain, while the paleocortical and subcortical limbic areas are more active. Also proposed was that limbic areas have minimal input from the dorsolateral prefrontal cortex in the dreaming brain.
The concept of 'repression' dates back to Freud, whereby undesirable memories can become suppressed in the mind. Dreams ease repression by permitting these memories to be reinstated.
A study showed that sleep does not benefit the forgetting of unwanted memories. Instead, REM sleep might even counteract the voluntary suppression of memories, making them more accessible for retrieval.
Two types of temporal effects characterize the incorporation of memories into dreams:
The day-residue effect, involving immediate incorporations of events from the preceding day
The dream-lag effect, involving incorporations delayed by about a week.
The findings of one study are consistent with the possibility that processing memories into dream incorporation takes a cycle of around 7 days, and that these processes help to further the functions of socio-emotional adaptation and memory consolidation.
A recent study aiming to explore autobiographical memories (long-lasting memories about the self) and episodic memories (memories about discrete episodes or events) within dream content amongst 32 participants found that:
One dream (0.5%) contained an episodic memory
The majority (80%) was found to contain low to moderate incorporations of autobiographical memory features.
Researchers suggest that memories for personal experiences are experienced fragmentarily and selectively during dreaming, perhaps in order to integrate these memories into the long-lasting autobiographical memory.
A hypothesis stating that dreams reflect waking-life experiences is supported by studies investigating the dreams of psychiatric patients and patients with sleep disorders, i.e., their daytime symptoms and problems are reflected in their dreams.
In 1900, Freud described a category of dreams - "biographical dreams" - that reflect historical infantile experience without the typical defensive function. Many authors agree that some traumatic dreams perform a function of recovery.
One paper hypothesizes that the predominant aspect of such traumatic dreams is the communication of an experience that the dreamer has in the dream, but does not understand.
The themes of dreams can be linked to the suppression of unwanted thoughts and, as a result, an increased occurrence of the suppressed thought in dreams.
Fifteen good sleepers were asked to suppress an unwanted thought 5 minutes prior to sleep. The results demonstrated increased dreams about the unwanted thought and a tendency to have more distressing dreams. Moreover, the data imply that thought suppression may lead to significantly increased mental disorder symptoms.
Research has indicated that external stimuli presented during sleep can affect the emotional content of dreams. For example, the positively-toned stimulus of roses in one study yielded more positively themed dreams, whereas the negative stimulus of rotten eggs was followed by more negatively themed dreams.
Typical dreams are defined as dreams with similar contents reported by a high percentage of dreamers. Up to now, the frequencies of typical dream themes have been studied with questionnaires and these have indicated that a rank order of 55 typical dream themes has been stable over different sample populations. The 55 dreams themes are:
School, teachers, studying
Being chased or pursued
Arriving too late
A person now alive being dead
Flying or soaring through the air
Failing an examination
Being on the verge of falling
Being frozen with fright
A person now dead being alive
Being physically attacked
Eating delicious food
Being locked up
Insects or spiders
Your teeth falling out/losing your teeth
Being tied, unable to move
Being inappropriately dressed
Being a child again
Trying again and again to do something
Being unable to find, or embarrassed about using a toilet
Discovering a new room at home
Having superior knowledge or mental ability
Losing control of a vehicle
Wild, violent beasts
Seeing a face very close to you
Having magical powers
Vividly sensing, but not necessarily seeing or hearing, a presence in the room
Floods or tidal waves
Seeing yourself as dead
Being half awake and paralyzed in bed
Lunatics or insane people
Seeing yourself in a mirror
Being a member of the opposite sex
Being smothered, unable to breathe
Encountering god in some form
Seeing a flying object crash
Seeing an angel
Creatures: part animal, part human
Tornadoes or strong winds
Being at a movie
Traveling to another planet
Being an animal
Seeing a UFO
Someone having an abortion
Being an object.
Authors have hypothesized that one cluster of typical dreams (object endangered, falling, being chased or pursued) is related to interpersonal conflicts; another cluster (flying, sexual experiences, finding money, eating delicious food) is associated with libidinal motivations; and a third group (being nude, failing an examination, arriving too late, losing teeth, being inappropriately dressed) is associated with superego concerns.
Dreams were evaluated in people suffering different types of headache.Results showed people with migraine had
increased frequency of taste and smell dreams.
This may suggest that the role of some cerebral structures,such as amygdala and hypothalamus,are involved in
migraine mechanisms as well as in the biology of sleep and dreaming.
Music in dreams is rarely reported in scientific literature.However,in a study of 35 professional musicians and
30 non-musicians,the musicians experienced twice as many dreams featuring music compared with non-musicians.
Musical dream frequency was related to the age of commencement of musical instruction but not to the daily load
of musical activity.Nearly half of the recalled music was non-standard,suggesting that original music can be
created in dreams.
Although it has been shown that realistic, localized painful sensations can be experienced in dreams - either through direct incorporation or from memories of pain - the frequency of pain dreams in healthy subjects is low.
Twenty-eight non-ventilated burn victims were interviewed for five consecutive mornings during their first week of hospitalization. Results found:
39% of patients reported pain dreams.
Of those experiencing pain dreams, 30% of their total dreams were pain related.
Patients with pain dreams showed evidence of worse sleep, more nightmares, higher intake of anxiolytic medication, and higher scores on the Impact of Event Scale.
Patients with pain dreams also had a tendency to report more intense pain during therapeutic procedures.
More than half of the sample did not report pain dreams, but these results could suggest that pain dreams occur at a greater frequency in suffering populations than in normal volunteers.
Recent findings link frontotemporal gamma EEG activity to conscious awareness in dreams. The study found that current stimulation in the lower gamma band during REM sleep influences ongoing brain activity and induces self-reflective awareness in dreams. Researchers concluded that higher order consciousness is related to synchronous oscillations around 25 and 40 Hz.
Recent research has demonstrated parallels between romantic attachment styles and general dream content.
Assessment results from 61 student participants in committed dating relationships of six months duration or longer revealed a significant association between relationship-specific attachment security and the degree to which dreams about romantic partners followed. The findings illuminate our understanding of mental representations with regards to specific attachment figures.
There has been an increase in the percentage of people who report flying in dreams from 1956 to 2000; investigators have proposed this increase may reflect the increasing amount of air travel
The dream content of psychiatric inpatients who had been admitted because of suicidal attempts was compared with three inpatient control groups who had been admitted for:
Depression and suicidal ideation without attempt
Depression with no suicidal ideation
Commission of a violent act without suicide.
Results confirmed that both suicidal and violent patients have more death content and destructive violence in their dreams, but also that this was a function of the severity of depression and certain character traits such as impulsivity, rather than being specific to the behavior itself.
A study investigating anxiety dreams in 103 children aged 9-11 years observed:
Girls reported a higher frequency of anxiety dreams than boys, although they could not remember their dreams more often.
Girls dreamt more often than boys about the loss of another person, of falling, of socially disturbing situations and small animals, of animals as aggressors, of family members (mainly siblings) and other female persons of known identity.
A study of older children and adolescents aged 10-17 years, comparing those with neurotic disorders with healthy subjects, found in left-handers:
Subjects expressed less novelty factor and frequent appearance of rare phenomena, such as "déjà vu in wakefulness," reality, "mixed" (overlapped) dreams, prolonged dreams in repeat sleep, frequent changes of personages and scenes of action.
Dream peculiarities detected only in neurotic patients but not in healthy subjects emerged as lucid phenomena deficit, "dream in dreams" and "dream reminiscence in dream" syndrome, only found in left-handers.
Right and left hemispheres seem to contribute in different ways to a dream formation. Authors from the study believe that the left hemisphere seems to provide dream origin while the right hemisphere provides dream vividness, figurativeness and affective activation level.
During studies comparing the dreams of pregnant and non-pregnant women:
Baby and child representations were less specific in the late third trimester than in the early third trimester and than in non-pregnant women.
Pregnant groups also had more pregnancy, childbirth and fetus themes.
Childbirth content was higher in late than in early third trimester.
Pregnant groups had more morbid elements than the non-pregnant group.
Those that give care to family or patients often have dreams related to the person or care given. A study following the dreams of adults that worked for at least a year with patients at US hospice centers noted:
Patients were generally manifestly present in participants' dreams, and dreams were typically realistic.
In the dream, the dreamer typically interacted with the patient as a caretaker but was also typically frustrated by the inability to help as fully as desired.
It is widely believed that oppressive dreams are frequent in bereavement. A study analyzing dream quality, as well as the linking of oppressive dreams in bereavement, discovered:
Oppressive dreams occurred at a significantly higher frequency in the first year of bereavement
Oppressive dreams were significantly associated with anxiety and depressive symptoms.
In another study of 278 bereaved persons:
58% of respondents reported dreams of their deceased loved ones, with varying levels of frequency
Most participants reported that their dreams were either pleasant or both pleasant and disturbing, and few reported purely disturbing dreams
Prevalent dream themes included pleasant past memories or experiences, the deceased free of illness, memories of the deceased's illness or time of death, the deceased in the afterlife appearing comfortable and at peace, and the deceased communicating a message
60% of participants felt that their dreams impacted upon their bereavement process.
Can dreams predict the future?