An out-of-body experience (OBE or sometimes OOBE), is an experience that typically involves a sensation of floating outside of one's body and, in some cases, perceiving one's physical body from a place outside one's body (autoscopy). The term out of body experience was introduced by Robert Monroe in 1971 as a bias-free alternative to belief-centric labels such as "astral projection" or "spirit walking". Though the term usefully distances researchers from scientifically problematic concepts such as the soul, scientists still know little about the phenomenon. One in ten people has an out-of-body experience at some time in their lives. OBEs are often part of the near-death experience, and reportedly may also lead to astral projection. Those who have experienced OBEs sometimes claim to have observed details which were unknown to them beforehand.
In some cases the phenomenon appears to occur spontaneously; in others it is associated with a physical or mental trauma, use of psychedelic drugs, dissociative drugs, or a dream-like state. Many techniques aiming to induce the experience deliberately have been developed, for example visualization while in a relaxed, meditative state. Recent (2007) studies have shown that experiences somewhat similar to OBEs can be induced by direct brain stimulation. Some of those who experience OBEs claimed to have willed themselves out of their bodies, while others report having found themselves being pulled from their bodies (usually preceded by a feeling of paralysis). In other accounts, the feeling of being outside the body was suddenly realized after the fact, and the experiencers saw their own bodies almost by accident. OBEs often occur during the borderline stage between REM sleep and arousal when sleep paralysis may persist and dream imagery may mingle with sensory input.
Some neurologists have suspected that the event is triggered by a mismatch between visual and tactile signals. They used a virtual reality setup to recreate an OBE. The subject looked through goggles and saw his own body as it would appear to an outside observer standing behind him. The experimenter then touched the subject at the same time as a rod appeared to touch the virtual image. The experiment created an illusion of being behind and outside one's body.
A lucid dream is a dream in which the person is aware that they are dreaming while the dream is in progress, also known as a conscious dream. When the dreamer is lucid, they can actively participate in and often manipulate the imaginary experiences in the dream environment. Lucid dreams can be extremely real and vivid depending on a person's level of self-awareness during the lucid dream.
A lucid dream can begin in one of two ways. A dream-initiated lucid dream (DILD) starts as a normal dream, and the dreamer eventually concludes that they are dreaming, while a wake-initiated lucid dream (WILD) occurs when the dreamer goes from a normal waking state directly into a dream state with no apparent lapse in consciousness. Lucid dreaming has been researched scientifically, and its existence is well established. Scientists such as Allan Hobson, with his neurophysiological approach to dream research, have helped to push the understanding of lucid dreaming into a less speculative realm.