In the terminology of ghost hunting, residual hauntings, also known as restligeists (German loan word from restlich meaning "residual" and geist meaning "ghost"), are repeated playbacks of auditory, visual, olfactory, and other sensory phenomena that are attributed to a traumatic event, life-altering event, or a routine event of a person or place, like an echo or a replay of a videotape of past events. Ghost hunters and related paranormal television programs say that a residual haunting, unlike an intelligent haunting, does not directly involve a spiritual entity aware of the living world and interacting with or responding to it.
One of the first to promulgate the hypothesis of residual haunting was Thomas Charles Lethbridge in books such as Ghost and Ghoul, written in 1961. The subject was explored in Peter Sasdy's 1972 television play The Stone Tape, written by Nigel Kneale. The explanation offered in the play is that light waves are recorded in the walls of a building when they interact with brain waves associated with fear, and the recorded images are reproduced when triggered by brain waves from a fearful observer. The popularity of the programme has led to residual haunting becoming known colloquially as the "Stone Tape theory."
- ↑ Green, Nigel Kneale/Peter Sasdy: The Stone Tape.