Dreams

Dreams are sequences of images, sensations, speech and movement occurring in the mind during sleep. The person dreaming typically perceives these events as real while they happen, but upon waking may remember part of them or forget them entirely. Dreaming is a common occurrence in all people, and it is believed that many mammals also pass through sleep stages similar to those in which dreams occur.

Modern sleep research focuses on the stages of sleep. Sleep has cycles, one of which is called REM (rapid eye movement). During that stage the body is largely still, but the brain is active, and the dreams that emerge are typically elaborate and narrative in structure. Simpler dreams or thought-like dreams also occur during non-REM stages.

Characteristics of Dreams

Dreams are recognized by several features: time and place shift constantly, illogical things occur without the sleeping person questioning them, and strong emotions such as fear, joy or anxiety arise. Dream memory is fleeting—most people remember only dreams from shortly after waking. Disturbing dreams that wake the person are called nightmares or night terrors; if they recur persistently they may be associated with psychological distress or prior brain injury.

Early Interpretation and Culture

Early societies saw dreams as messages or signs of the future. In Islam, dreams are categorized into types, with one category considered good dreams. In Somali poetry and oral tradition, dreams play a role in stories and proverbs, and interpretation was sometimes sought from people recognized as skilled interpreters. These interpretations differ from scientific approaches, as they do not rest on measurable evidence.

Psychological and Neurophysiological Views

In the early twentieth century, Sigmund Freud proposed that dreams are a route to unconscious desires. That theory is not now widely used in research. Other theories suggest that the brain during sleep consolidates memory and integrates new information into long-term storage, and that dreams are a byproduct of this process. Another view sees dreams as a rehearsal of emotion and threat response. No single theory commands agreement among all scholars.