The multi-faceted nature of dreams makes it easy to find connections between dream content and real events. The term "veridical dream" has been used to indicate dreams that reveal or contain truths not yet known to the dreamer, whether future events or secrets.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. Another experiment gave subjects a fake diary of a student with apparently precognitive dreams. This diary described events from the persons 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. Images and literature
Graphic artists, writers and filmmakers all have found dreams to offer a rich vein for creative expression. In the West, artists depictions of dreams in Renaissance and Baroque art often were related to Biblical narrative. Especially preferred by visual artists were the Jacobs Ladder dream in Genesis and St. Josephs dreams in the Gospel according to Matthew. Many later graphic artists have depicted dreams, including Japanese woodblock artist Hokusai (1760–1849) and Western European painters Rousseau (1844–1910), Picasso (1881–1973), and Dali (1904–1989). In literature, dream frames were frequently used in medieval allegory to justify the narrative; The Book of the Duchess and The Vision Concerning Piers Plowman are two such dream visions. Even before them, in antiquity, the same device had been used by Cicero and Lucian of Samosata.
A dream is a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. Humans spend about two hours dreaming per night, and each dream lasts around 5 to 20 minutes, although the dreamer may perceive the dream as being much longer than this.The content and function of dreams have been topics of scientific, philosophical and religious interest throughout recorded history. Dream interpretation, practiced by the Babylonians in the third millennium BCE and even earlier by the ancient Sumerians, figures prominently in religious texts in several traditions, and has played a lead role in psychotherapy. The scientific study of dreams is called oneirology. Most modern dream study focuses on the neurophysiology of dreams and on proposing and testing hypotheses regarding dream function. It is not known where in the brain dreams originate, if there is a single origin for dreams or if multiple regions of the brain are involved, or what the purpose of dreaming is for the body or mind. The human dream experience and what to make of it has undergone sizable shifts over the course of history. Long ago, according to writings from Mesopotamia and Ancient Egypt, dreams dictated post-dream behaviors to an extent sharply reduced in later millennia. These ancient writings about dreams highlight visitation dreams, where a dream figure, usually a deity or a prominent forebear, commands the dreamer to take specific actions and may predict future events.