Dream

Lore & Background

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 brain or mind).

Reader's Guide

Dreams occur mainly in the rapid-eye movement (REM) stage of sleep—when brain activity is high and resembles that of being awake. However, humans dream during non-REM sleep, also, and not all REM awakenings elicit dream reports. To be studied, a dream must first be reduced to a verbal report, which is an account of the subject's memory of the dream, not the subject's dream experience itself. Therefore, dreaming by non-humans is currently unprovable, as is dreaming by human fetuses and pre-verbal infants.

Did You Know?

• In Old English, the word drēam was used to describe 'noise', 'joy', or 'music', but not related to sleep-induced brain activity.
• In the Hall study, the most common emotion experienced in dreams was anxiety. Negative emotions were much more common than positive ones.
• People who are blind from birth do not have visual dreams. Their dream contents are related to other senses, such as hearing, touch, smell, and taste, whichever are present since birth.