Dreams are successions of images, ideas, emotions, and sensations that occur involuntarily in the mind during
certain stages of sleep. 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. The scientific study of dreams is called neurology.
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.
The
length of a dream can vary; they may last for a few seconds, or approximately
20–30 minutes. 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. 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.
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.[6] Dreams can at times make a creative thought occur to the person or give a
sense of inspiration.
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.
Sigmund
Freud, who developed the discipline of psychoanalysis,
wrote extensively about dream theories and their interpretations in the early
1900s. [9] 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.
