An umbrella term used to describe an extraordinary physical or mental state, not usually experienced in daily life. Such states comprise hypnagogic hallucinations (as in daydreaming), fantasizing, hallucinations, hypnosis, trances, deathbed visions, spirit possession, and out-of-body experience. Such states occur among all peoples, and are usually brought about by changes in body chemistry, which can occur naturally through disease, by taking hallucinatory drugs, through practices like fasting, drumming, twirling the body, shaking the head, or through psychological suggestion.
There are two ways of thinking about such altered states. The traditional ancient explanation proposes that the states are temporary change of location for the individual who believes he or she is actually entering into and participating in a spirit world. Modern psychological explanations recognize these states as being localized within and generated by the brain’s cognitive system.